起重机中英文对照外文翻译文献

Digital Drive Crane Hoist ConversionWhile working on the bridge of a crane, I remember feeling the intense heat of the speed reduction Resistors. I looked over the prints and tried to figure out how to reduce this energy loss. As I understood, heat is the product of energy lost (R I 2). I was new to crane maintenance in 1990 and, having an electrical/electronic background,Crane panel manufacturers desired a novel method of crane control that combines new technology with some of the oldest. The new crane panel resulted in lower costs, increased productivity and reduced wear on components, as well as energy savings.I believed new technology existed. Several of the newer devices needed alternating current input. SCRs, VFDs and PMWs were becoming common acronyms in newer plants. The possibility of upgrading our pre-existing 250 VDC distribution was cost-prohibitive, Various transistors could run DC, but not at the ampere demands we needed. With crane panel replacement under consideration, we challenged our panel suppliers to develop new crane control technologyDigital Hoist ConversionSeverstal North America Inc. is an integrated steel mill dating back to 1917, when Henry Ford built it to supply his Ford Motor Co. auto manufacturing enterprise. It was operated as Ford Steel Division ur~ti11982, when it became Rouge Steel Co. In 2004, OAt Severstal Steel purchased the assets of Rouge Industries and Rouge Steel.Figure1.A digital drive controller was installed Figure2. Preliminary setup of DDC hoist panel on this 135-ton-capacity slab-handling craneThe market price for steel was flat in the early part of the new millennium, forcingdepartmental groups to look for cost-saving improvements. One improvement was the installation of a new type of digital electronic control panel in 2003. This panel represented the introduction of DC electronic crane control to Rouge Steel and the largest duplex crane hoist controller (dual 200-hp) of its type in North America.The original panels were built on a P&H 135-ton slab-handling crane having standard DC hoisting contactor controls. They were industrial and functional, designed to handle the loads of this crane in 1972. The loads are greater now with heavier slabs, runing the crane at maximum limits and higher production rates. This caused premature equipment failures and production down-time. With three aging cranes in this bay, maintenance costs were rising to new highs. Those involved in maintenance were finding that distributors and manufactures were downsizing or had gone out of business, making replacement parts costly or obsolete. The market drivers of today are forcing the change to newer technologiesFigure3. Digital panel installed on crane trolley deck Figure4.Prewired resistors reduced start-uptimeA novel design approach was asked of the crane panel manufactures. They replied with a proposed partnership and an effort to add some of the newest technology to the oldest methods of crane controls. The result was high-current transistor switching with a 250 VDC input. The design was well-thought-out and included integrating the original motors, limits, switches and wiring. Now speeds are controlled by sending the motors only enough current to safely lift and lower the load. The motors are soft stopped (reverse plugged) before the brakesclose. This saves wear on components, reduces costs and increases productivity. Without the need for reduction resistors, there is no energy wasted, maximizing the energy savings. The panel installation of the SY-4 crane was completed in 2003 and is still running. The results are smoother movements with little energy loss (heat).The new panels were designed for installation on the trolley deck, as opposed to the bridge deck.. This aids in troubleshooting and reduces excessive wiring mainly at the weak point of the cable powertrack.. This allowed the time and ability to perform all setup work during mini-downturns without disabling the original hoist. The original panel was left in place as a backup, as failures could not be predicted. To date, the fail-safe panel has not been required.The panels were pre-wired and pre-tested prior to crane installation, further reducing crane downtime. When the transfer day came, only the master switch, motors and limit leads needed to be rerouted to the new system. On-the-job tuning and monitoring were vital for the first couple of days. It was important to have crane operators involved for that “personal feel”and to obtain their buy-in to the project, to increase awareness and productivity. No-load and full-load current tests were run with great results.An aded benefit to this control is the electrical current savings. Without reductin resistors for speed points, and with the added benefit of power produced when regenerative lowering, this single crane installation saves more than ＄25000 in electricity annually. This can be a very important consideration if substation power is near critical usage levels. The demand this system imposes is much less than a similar contactor system. With energy costs on the rise, this is a concern for every project considered. Figure 5 indicates an example of electrical current savings potential by comparing contactor panel loads(top) to digital drive loads(bottom).How it works in the circuit is not unique. The insulated gate bipolar transistor(IGBT) takes the place of the contactors and acceleration resistors. As the master switch is selected for greater speed, the circuitry triggers the transistor at a frequency(pulse width modulated) that allows current to flow through the IGBT. The current circulates in the standard series armature and series field along with the series brake. The longer the input is turned on, thehigher the output average voltage (Figure 6). The higher the voltage, the higher the horsepower produced. This system can provide high torque with low currents(heat) as the result of motor regenerative properties. High speed with no load can also be accomplished. Much of this could not be achieved with the original panels.Figure5.Example of energy saved during lowering sequence.The difference is noticed when the IGBT is in its off cycle(Figure 7). In this instance, the motor acts as a generator, producing circulating currents through the flyback diode and maintaining self-induced motor currents. This effect reduces ripple and provides current that was not provided by the original power source. The reduction of current loads on system feeders and hardware further adds to the total savings package.The following items are important considerations when determining if this system will work with an application.IGBTs are the newest part of the design that makes this panel work with 250 volts DC. They combine the advantages of the bipolar transistor(high voltage and current) with the advantages of the metal oxide semiconductor field effect transistor(MOSFET)(low power consumtion and high switching). IGBTs are semiconductors that combine a high voltage and high current bipolar junction transistor(BJT) with a low-power and fast-switching MOSFET. Consequently, IGBTs provide faster speeds and better drive and output characteristics than power transistors and offer higher current capabilities than equivalent high-powered transistors.Figure6.Hoist current flow when the IGBT is onFigure7.Hoist continuing motor current flow when the IGBT is off.Heat sinking, including consideration of air temperature and air flow, is essential to the proper operation of any solid-state reply. It is necessary to rovide an effective means of removing heat from the IGBT. The importance of using a proper heat sink cannot be overstressed, since it directly affects the maximum usable load current and maximum allowable ambient temperature. Up to 90 percent of the problems with transistors are directly related to heat. Lack of attention to this detail can result in improper switching(lockup) or even total destruction of the IGBT. If the device ever reaches an internal temperature of 105℃, it will be permanently destroyed. One of the problems encountered at Severstal NA was program temperature cutbacks due to excessive heating. When electrical current cutback does not control the drive, it will stop on software limits. Transistors develop heat as a result of a forward voltage drop through the junction of the IGBT. Beyond this point, heat will cause a reduction(software cutback) of the load current that can be handled. If the demand is too great,the program is designed to shut down.Care must be taken when mounting solid-state relays(SSRs) in a confined area. SSRs should be mounted on individual heat sinks whenever possible. SSRs should never be operated without proper heat sinking or in free air, as they will thermally self-destruct under load. A simple way to monitor temperature is to slip a thermocouple under a mounting screw. If the base temperature does not exceed 45℃, the SSR is operating at its optimal level. Remember that the heatsink removes the heat from the SSR and transfers that heat to the air in the electrical enclosure. In turn, this air must circulate and transfer its heat to the outside ambient. Vents and forced ventilation are good ways to accomplish this. Semiconductor fuses are the only reliable way to protect SSRs. They are also referred to as current-limiting fuses, providing extremely fast opening while restricting let-through current far below the fault current that could destroy the semiconductor. This type of fuse tends to be expensive, but cheap by comparison to the damage that could occur, providing a means of fully protecting SSRs against high current overloads. An RI2fuse rating is useful in aiding in the proper design of SSR fusing. This rating is the benchmark for an SSR's ability to handle a shorted output condition. Devices such as circuit breakers and slow blowfuses cannot react quickly enough to protect the SSR in a shorted condition and are not recommended. Every SSR has an I2rating. The idea is to select a fuse matching the capability of the solid-state relay for the Tsame duration.Figure8.IGBT and components mounted on heat Figure9.External mounted fans removed IGBT heatFigure10. Panel fans removed internal heat buildup Figure11. Semiconductor fuses provide the bestprotection for solid-state relays Motor switching and dynamic loads, such as motors and solenoids, can create special problems for SSPs. High initial surge current is drawn because its star t-up impedance is usually very low. As a motor rotates, it develops a counter electromotive force (CEMF) that resists the flow of currenL This CEMF can also add to the applied line voltage and create over-voltage conditions during turn-off and regenerative times. It should be noted that over-voltage caused by inductive voltage doubling or CEMF from the motor cannot be effectively dealt with by adding voltage-transient suppressors. Suppressors such as metal oxide varistors (MOVs) are typically designed for brief high-voltage spikes and may be destroyed by sustained hlgh-energy conduction. V oltage dump resistors may be needed in extreme cases and should be engineered to meet a system's demand, It is therefore important that SSRa are chosen to withstand the highest expected sustained voltage.Problems encountered while running the200-hp dual drive were few hut worth mentioning. The program allows for setdng many variables (i.e., speed, currents, brake-open voltage). Most of these are detrimental to the drive or motor if set incorrectly. Although staying within the drive specifications is safe, this may not produce the desired actions. Ambient temperatures must also be considered, since most useful application are near higher-temperature areas. Following are several problems(and solutions) observed during installation and trials:Problem 1:The first problem presented itself when applying excessive brake-open curent.The direction contactors were flashed and pitted. Also, the emergency brake contactor appears bluish from high heat. Reducing brake-open current and power-on time to a shorter duration solved the problem.●Problem 2:Hall effect transistors and IGBT were thought to be faulty parts and/or wiring, but this could not be duplicated. Many suspect parts were replaced, but it was determined that internal panel ambient temperature was the problem. This was solved with cooling fans on the doors and on the IGBT cooling fins.●Problem 3:Temperature cutbacks usually led to errors. It was found that a new crane operator did not like operating the hoist at full speed. Longer run time and higher IGBT cycles caused unnecessary heating in panels. Reducing field current settings eased this problem. This increased the lowering speeds but greatly reduced the IGBT voltage drop, in turn reducing its heat dissipation. Cooling fans eliminated the problem.●Problem 4:All power must be disconnected from the line because all lines feed from a common bus capacitive filtering system. This means that the typical way of “pulling motor disconnect and running the controls only”to troubleshoot does not work. The panel diagnostics and troubleshooting information provided is very helpful.●Problem 5:Lack of electronic knowledge by the electricians is a concern. When production downtime is critical, the time to troubleshoot is a high-priced commodity. This ultimately puts pressure on the electricians, causing frustration. The solutions was to ensure that the crew is involved Mth project design and installation. Training is vital. If the maintenance team is nat up to speed with the technology, failure is probable. Two training classes were held for all electrical team members.After one year, the actual materials maintenance and labor savings were calculated, with a payback of 6.2 months. Cost savings and efficiency gains were greater than expected. This led the way to the next drive conversion, which was scheduled for 2006. With a cooperative effort by salespersons, manufacturers, engineers and end-users, Severstal NA vastly improved its ability to compete successfully.AcknowledgmentsThe author would like to acknowledge the efforts of former general supervisor FredSchwartz and the crew at Severstal North America. Without their help, the project may never have gotten this far.References1. Creech, R., 'Energy Savings -- DC Digital and DC Contactor Hoist Control System," Iron ~ Steel Technotogg, May 2005, pp. 225-228.2. /modval/database/contents/reports/igbt.html3. /computing/unix/software/matlab/toolbox/powersys/igbt.html4. /old_pdf/app_ notes/r_ipm.pdf5. /access/helpdesk_r13/help/toolbox/physmod/powersys/igbt.html数字机起重机提升转换虽然工作在桥上的吊车，我记得感觉酷热的速度减少电阻.我看着图纸，并试图弄清楚如何减少这种能源损失.正如我的理解一样，热是产品的能源损失（RI2）。

毕业设计中英文翻译Crane history, classification and prospects起重机发展史、分类及前景Concept Crane (Crane) is a kind of lifting, Is a for loop Intermittent motion machinery. A work cycle, including: Extract plant extract to the items from the institute, Then move to the designated location lowered the level of items Then, the reverse movement, Back to extract device in situ for the next cycle.Usually by the crane hoisting mechanism (the items up and down movement), Operating agencies (the lifting movement), Luffing and slewing mechanism (the articles for the horizontal movement), Coupled with the metal body Power plant, Control and manipulation of a combination of the necessary auxiliary equipment. Type In the bridge used in the construction crane, According to its structure and properties of different Can be divided into light and small lifting equipment, Bridge type crane and jib type crane three categories. Small-sized lifting equipment such as: Jack, Gourd, Winch and so on. Such as the type of crane girder bridge cranes, Gantry cranes.Type of crane boom, such as fixed slewing cranes, Towercrane, Crane, Tires, Crawler cranes.Within a certain range to enhance the vertical and horizontal multi-action heavy lifting crane. Also known as the crane. Are material handlingmachinery. Crane's work is characterized by intermittent exercise to do, That is expected to take a work cycle, Migration, Unloading the corresponding body is alternately moves the work. Prototype crane Ancient Chinese irrigation of farmland is used orange prototype type cranes. The 14th century, Western Europe, human and animal-driven emergence of the rotation type cranes. Early 19th century, There bridge crane; Important wear parts such as crane shaft Spreader and other gear and began to use metal materials, and introducing the hydraulic drive. The late 19th century, Gradually replaced steam-driven crane crane with hydraulic drive. 20th century, 20's, the electrical industry and the rapid industrial development of internal combustion engines, To motor or internal combustion power plant basically formed of various cranes.Cranes include hoisting mechanism, Run institutions, Luffing, Slewing mechanism and metal structure. Crane hoisting mechanism is the basic working body Mostly formed by the hanging system and winch, Also lift heavy objects through the hydraulic system. Operating agencies to adjust the vertical or horizontal transport heavy cranes working position, Generally by the motor, Reducer, Brake and wheel components. Luffing jib crane in only with, the When looked up and boom amplitude and Bent over when the rate increases, Points amplitude balance both amplitude and non-equilibrium. Slewing mechanism for rotating the arm, By the drive and the rotary bearing device composition. Crane metal structure is the skeleton, Main bearing parts such as bridge, Arm and the door frame structure or for the box truss structure, but also for web structure, Some are available as supporting steel beams. Crane according to the structure of the different classification:Crane beam 1 Beam crane. Over a rectangular space in its operations, Used for workshops, Warehouse, Open yard loading and unloading of goods, etc., A beam crane, Crane, Gantrycranes, Crane, Carrying bridges.① beam crane: Beam cranes including single girder overhead crane and double girder overhead craneSingle girder overhead crane girder bridge of the word to use more steel or steel type and steel composite section. Crab often hand chain hoist, Hoist electric hoist or lifting mechanism as assembled parts.Supported by bridge type and the hanging of two. The former bridge crane beam along the orbit vehicles; The latter suspension bridge along the roof of the plant under the crane track. Single girder overhead crane points manually, Electric two. Manual single girder overhead crane operating speed of the lower body, Starting weight is also smaller, But their quality is small, Facilitate the organization of production, Low cost, When the power handling capacity fornon-small, Speed and productivity for less demanding applications.Manual Single-girder overhead crane with manual monorail car as a running car, Hand pull hoist as the lifting body Bridge from the main beam and side beams formed. Generally use the single main beam I-beam, End beam is bent shape with a steel or welded steel plate.Electric single girder overhead crane speed, Higher productivity than manual, From the weight as well. Electric single girder overhead crane by the bridge, Traveling mechanism, Electric hoist and electrical equipment components.② bridge crane:Overhead bridge crane is a bridge in the orbit of a bridge crane, Also known as the crane. The bridge crane lay along the elevated track in the vertical sides of runs Lifting trolley along the track laid on the bridge on the horizontal run The scope of work constitutes a rectangular, Can take full advantage of the space under the lifting bridge materials Ground equipment is not hindered.Bridge crane is widely used in indoor and outdoor storage, Plant, Pier and open storage yard, etc.. Overhead crane bridge crane can be divided into ordinary, simple beam bridge crane and metallurgical three special crane.General bridge crane lifting trolley generally, Bridge run institutions, Bridge the metal structures. Crab and the hoisting mechanism, Car run institutions and small frame of three parts.Lifting mechanism including motors, Brakes, Reducer, Reels and pulleys. Motor through reducer, Driven drum rotation, The rope around the drum or from the reel down, To lift heavy objects. Is supporting for small frame and installation of lifting the car to run institutions, agencies and chassis components, Usually welded structure.2 Cantilever crane (jib crane)Cantilever crane with high column, Wall, Three forms of balance crane.① is a cantilever crane cantilever column can be fixed around the column base fixed on the rotary, Column with the transfer or rigid cantilever, Together within the base support in the vertical center line of rotation relative to the columns and cantilever formed by the cantilever crane. It applies from the weight of small, Operating range of services to round or fan of the occasion. Generally used for machine tools and handling the workpiece chucking.Pillar jib cranes to use more electric chain hoist for lifting mechanism and operation of institutions, Less use of wire rope hoist and chain hoists. Rotation and horizontal movement to use more manual work, Only from the weight of the larger When using electric.② wall crane is secured to the wall on the cantilever crane, Or you can along the wall or other support structure on an elevated track running on the cantilever crane.Line where the wall using a crane to span a larger Large workshop building height or warehouse, Close to the wall near the lifting operation at the more frequent the most suitable. Multi-wall line and the top of the crane or bridge crane beam with the use of Near the wall at the service in a rectangular space, Responsible for the lifting of light and small objects, Large bridge crane from the beam or commitment.③ balance crane balance known as hoists, It is the principle of the use offour-bar linkage to balance the weight load and form a balanced system, Spreader using a variety of flexible and can easily load being lifted in the three-dimensional space. Balance crane lightweight and flexible, Is an ideal lifting small items of lifting equipment, Is widely used in factory floor machine loading and unloading, Process between Automatic line Production line of the workpiece, Sand box lifting, Parts assembly, And thestation, Terminals, Warehouse various occasions Crane organizationsdrive Can be divided into two main categories: One for focus driver That is driven by an electric motor on both sides of the active long-wheel shaft drive; The other for each driver, That is active on both sides of each wheel driven by an electric motor. In More frequent use of small crane brake, Gear and motor combined into one of the "triple play" Drive, From the weight of a large bridge crane for the general ease of installation and adjustment, Universal coupling drive is often used. Structure crane (crane) run institutions generally take the initiative and driven by four wheels, If the effect is very heavy, Commonly used methods to increase the wheel to reduce wheel pressure. When more than four wheels when Must be balanced with articulated frame device The crane's load evenly distributed throughout the wheel.Bridge's metal structure from the main beam and side beams composedof Divided into single-and dual-beam bridge girder bridge types. Single-girder bridge by a single span both sides of the main beam and in the end beam composition Double-beam bridge consists of two main beams and side beams formed.The main beam and side beams rigidly connected End beam at both ends with wheels, To support the elevated bridge in the running. The main beam welded track, For lifting the car running. Bridge girder type of structure more typical of a box structure, Four truss truss structure and fasting.Box structure can be divided into two-track box beams, Partial double-rail box beam, Partial rail box, such as several single main beam. Double-track box beam is widely used as a basic form From the main beam on Under both sides of the vertical flange and web components, Car rail arranged in the center of the flange on the line Its structure is simple, The convenience, Suitable for mass production, However, larger self.Partial double-rail box rail box beam and partial cross section of a single main beam are made on the Ranging from under the flange and web thickness of the main and auxiliary components, Arranged in the main web of rail carabove Cabinets can save short-stiffeners, One side rail box is a single main beam box girder flange width instead of two main beams, Weightless However, more complex manufacturing. Four from the four truss structure to form closed space plane truss structure Truss in the horizontal surface is paved walkway panels, light weight, Stiffness, But compared with other structures, Size large, Create more complex Lower fatigue strength, Have less production.Partial fasting truss structure similar to the rail box girder, Plate by the four form a closed structure, In addition to the main web is a real belly-section beams,the The remaining three pieces of steel plate cut into many windows in accordance with design requirements, The formation of a non-fasting truss diagonals, In the last, The surface of a horizontal truss walkway lined with boards, Crane agencies and electrical equipment installed in the bridge house, Lighter weight, Overall stiffness, This is a more widely used in China as a type.General bridge crane mainly electrically driven, Control room is usually the driver, There are remote control. From the weight of up to five hundred tons, Span of up to 60 meters.Simple beam bridge crane, also known as beam cranes, The structure and composition similar to ordinary bridge crane, Starting weight, Span and the pace of work are small.Bridge girder or other beam by beam and plate steel, consisting of a simple beam, Hand pull or electric hoist as the lifting hoist coupled with easy trolley car, the car is generally I-beam's bottom flange on the run. Bridge can be run along the elevated track, Can also be elevated along the suspension in the followingorbit This is called hanging beam crane cranes.Metallurgy crane in the steel production process to participate in a particular process operation, The basic structure and general overhead crane similar tothe However, lifting a small car is also equipped with a special working body or device. The cranes feature is the use of frequent Bad conditions High-level work. There are five types.Simple beam bridge crane type Casting crane Casting crane: For lifting hot metal into the mixer, Steel-making furnaces and the molten steel into a continuous ingot lifting equipment or ingot molds used. Master Sheng car lifting barrels, Sheng, deputy car to flip bucket and other auxiliary work.Tongs crane: Use tongs to heat ingot vertically lifted onto a soaking pit furnace, Or put it out into the car shipped spindles.Off ingot crane: Ingot from the ingot mold used in the extrusionforce. Small car off the tablets have a special device, Way off the ingot ingot mold according to the shape of the set: Some off the tablet press and hold the ingot rod Crane Yongxiang, Ingot mold with tongs lift; Some press and hold the ingot mold with tongs, Ingot with a small clamp lift.Charging crane: Added to the charge in the open hearth. Column with the bottom of the main car pick rod, And to stir it into the furnace hopper. The main column can turn around the vertical axis, Pick the rod can swing up and down and rotating. Vice-car heaters and other auxiliary operations for the repair.Forged Crane: Cooperation with the hydraulic press for forging a large workpiece. Special hook to hang the main car turned feeder, To support and flip the workpiece; Vice-car to lift the workpiece.Gantry cranes: bridge set the level of support legs form two gantry crane shape of a bridge. The crane on the ground orbit Mainly used in open storageyard, Dock, Power plants, Ports and railway stations and other places cargo handling and installation. Gantry crane hoisting mechanism, Car run institutions and bridge structures Basically the same with the bridge crane. The span, Crane bodies were driven mostly by way of To prevent the crane have skewing increased running resistance Even accidents. Gantry crane lifting trolley running on the bridge, Some crab is a type cranes. Bridge on both sides of the legs are generally rigid legs; Span of more than 30 meters, Side of the rigid legs often, While the other side of the bridge connection through the ball joints and flexible legs, The door frame to become statically determinate system, This prevents the outer lateral thrust loads caused by the additional stress Can also compensate for temperature deformation of vertical bridge gantry cranes wind area, to prevent thedecline in the strong wind lines or overturned, With wind instrument and with the operating agencies of the crane rail clamp interlock. Both ends of bridge can be no cantilever; Can also be one end or both ends of the cantilever cantilever, To extend the operating range. One end of a half bridge leg gantry crane, The other end without legs, Run directly on the high bench. Gantry cranes are divided into 4 types.① General gantry crane: The most versatile cranes, Can move into a variety of items and bulk materials, From the weight of 100 tons, a span of 4 to 35 meters. Common with the gantry crane grab a high-level work.② Hydropower Station Gantry Crane: mainly used for lifting and opening and closing gates, but also for the installation. 80 to 500 tons lifting capacity, small span, 8 to 16 meters; Lower lifting speed for 1 to 5 m / min. The lifting cranes, though not always, But once the work is very heavy use, So to improve the appropriate level.③ shipbuilding gantry crane: Berth assembly for the hull, Standing with two crab: There are two main hook one, Flange of the bridge on theorbit; Another has a main hook and a Vice-hook, In the bottom flange of the rail bridge run To flip and hoisting a large hull blocks. Weight is generally from 100 to 1500 tons; Span of 185 meters; Lifting speed of 2 to 15 m /min, There are 0.1 ~ 0.5 m / min micro speed.④ container gantry crane: For the container terminal. Trailer Bridge to Quay container carrying containers unloaded from the ship transported to the yard or the rear, by the stacking container gantry crane loading up or directly away, you can speed up the bridge or other crane container carrying turnover. Can be stacked high 3 to 4 layers 6 row wide container yard, General tire type, it also uses rail style. Container gantry cranes and container cross-car comparison The span and height of door frame on both sides of the larger. To meet the transportationneeds of the port, The higher level work crane. Lifting speed of 8 to 10 m / min; Across the span of the container needed to determine the number of rows, maximum of 60 meters corresponding to 20 feet, 30 feet, 40 feet long container from the weight of approximately 20 tons, 25 tons and 30 tons.④ carrying bridgeIncrease the span of the development by the gantry crane from a bridgecrane, Also known as the loading bridge. For open storage yard, Port and railway cargo terminals and other places. General delivery of large gantry crane bridge and a similar structure. Features are: ① mainly for handling large quantities of bulk materials; ② span, Generally more than 30meters, Some 170 meters; ③ jobs frequently, Highproductivity, Generally 500 to 1,500 tons / When Working speed is high, Lifting speed of 60 to 70 m / Points, Car speed is 100 ~ 350 m / Points, High-level work; ④ run institutions only carry the bridge to adjust the working position, Non-work institutions. When the span is large, The bridge of the bridge carrying on a rigid support legs and a flexible support legs. Bridge with two legs can be bolted connection; Connection with the flexible legs can also be ball joints or column joints, Relative to the flexible legs can have a range of skew bridge.Formed by the truss girder bridge, Crab in its winding rod or bottom chord of the track. Some cars with rotary boom, The equivalent of a run on the bridge type cranes.Container wharf in the port carrying the bridge is running, Is a special structure of large cranes, Dedicated to the ship's container handling work. Both sides of the generally rigid legs, The formation of a solid door frame, Bridge bearing fused with the door frame on the upper frame. With a container spreader (see cross-car) the car to run on the bridge. Long cantilever extending toward thesea is usually to pitch in. Non-operational state, Cantilever can be lifted at 80 °~ 85 °Elevation Department To carry over the bridge to the highest point on the ship. Operations cantilever flat. Also some cantilever is fixed.2. Double girder bridge craneDouble girder bridge crane from the straight track, Cranegirder, Crab, Power transmission systems and electrical controlsystem, Particularly suited to large hanging from the weight of the plane and large range of material handling.3 Type cranes. And over in the round ground operations, Used foropen-air loading and unloading and installation, etc., A crane, Floating cranes, Mast crane Wall line of cranes and deck cranes.4 Tower crane. Generally used in the site, Lifting supplies.5 Portal crane. Oh, generally used for the port. In addition, Cranes can also drive, Type of work, Mobility and use of such classification.Crane according to the different installation methods can be divided into:1 Truck Crane Truck CraneWill be installed in the general or special crane chassis of low disk performance is equivalent to the total weight of the truck the same vehicle, Meet the technical requirements for road vehicles, Thus the various types of road passage. Such cranes typically available on Off the two control rooms, Operations must be extended leg stable.Weight range from large, From 8 tons to 1,000 tons, Axle chassis number From 2 to 10. Is the largest output, The most widely used type of crane.2 Tire CraneLifting part of the pneumatic tire installed on a special cranechassis. Combined with an engine on and off, Speed is generally not more than 30KM / H, Vehicle width is wider, It is not appropriate long-distance driving on the highway. With no legs and hoists, traveling hoists features For the freight yard, Terminals, Move away from the site and other places with limited lifting operation.3 Off-road tire cranes are 70 developed a crane, Its function and tire hoist crane similar to Can also be carried out without legs and hoists, traveling hoists.The difference is the chassis structure and chassis by the unique structure brings improved driving performance. The engines are mounted on the crane chassis, the chassis has two axles and four large diameter off-road tire pattern. Four wheels are driving wheels and steering wheel, When the muddy uneven transfer station site, the Four wheels is transmitted power, The four-wheel drive, To improve through the muddy ground and uneven road ability. When the flat surface moving at a rapid pace, Front axle or rear axle with only two wheels driven To reduce energy consumption. Random file at the crane, Expressed by 4 × 4 wheel drive, 4 × 2, said four axles with two wheels in the wheel. The model for small venue work. Can achieve a continuous stepless variable speed, Resistance mutations in the case of the road will not turn off the engine, Thus a great convenience to the driver's operation. The off-road tires can be a performance extension of the crane, and Powerful and flexible tire crane.4 All Terrain CraneIs an off-road crane truck crane and both the characteristics of high performance products. It can not only transfer as fast as cranes, Long-distance travel, but also to meet in the narrow and bumpy or muddy field on the work request, The driving speed, Multi-bridge driver All-wheel steering, Three turnaround mode,ground clearance large High-climbing ability, No need for features such as lifting legs, Is a very promising product. But the price is higher, On the use and maintenance require a higher level.5 CraneA specific task to complete the development of special crane. For example: The implementation of tactical and technical safeguards to mechanized use, Off-road vehicles or armored personnel carriers mounted on the crane wheel rescue vehicle; To deal with road traffic accidents Wrecker, etc. Fall into this category.Crane Job Type: Refers to how busy the crane and load the parameters of degree of change.Busy work degree Crane for Means the total time in a year, The actual number of hours of crane operation and the ratio of total number of hours; Of institutions, Refers to an institution operating hours within a year and the ratio of total number of hours. In a working cycle of the crane, Agencies operating time percentage of Called the agency's duty cycle, By JC said.Degree of load changes, Designed by a crane rated capacity in actual operation, The load of the lifting crane is often less than the ratedcapacity. The degree of this change in load from the weight of the utilization factor k said. k = crane weight from the average of the actual year / crane's rated capacity.According cranes busy loading level and degree of change, Usually the type of cranes are: Light level, Intermediate, Heavy and Extra Heavy Grade 4 level.Cranes and lifting the types of work are two different concepts, Lifting capacity, May not be re-grade, From the weight of small, Not necessarilylight level. Such as hydropower capacity by the crane's lifting hundreds oftons, But the opportunity is rarely used, Only in the installation ofunits, When using the repair crew, Rest of the time stop there, So, although from very heavy, But still is light level. Another example is the use of the station yard gantry cranes, Although not from the weight, But the work is very busy Are heavy duty type of work.Crane safety performance of the types of work and has a very close relationship. Starting weight, Span The same crane lifting height, If the work of different types, In the design manufacture, Safety factor is not taken by the same That is, parts and components model, Size, Specifications vary. Such as wire rope, brake as a result of different types, Different safety factor (light-level security coefficient is small, Heavy duty safety factor) , The selected model is not the same. Then, as is the 10t bridge crane, For the intermediate type of work (JC = 25%) The lifting motor power N = 16KW, As for the heavy duty type of work (JC = 40%) Lifting motor power compared to N = 23. 5KW.From the above we can see that If the light level work crane type used in heavy duty type of work place Cranes will often faulty, Of safe production. Therefore, security checks, Crane should pay attention to the type of work and working conditions must be consistent.Crane characteristic curve: the carrying capacity of the crane structure, Boom lifting capacity and stability against overturning three whole envelope curve.Practice double girder bridge crane2.33. 1 Work agoa. On the brakes, Hook, Steel wire rope and safety devices and other components required by point inspection card check Abnormalphenomena Should be excluded.b. The operator must be sure to go when no one Taiwan, or track, Can close the main power supply. When the power circuit breaker or a sign on the lock when The people concerned should be removed before the original closing the main power supply. Crane safety devices which In order to ensure safe and reliable lifting operation, Crane with a better safety devices To accidental circumstances, Protects the device or to remind the operator attention To play a security role.1. Hydraulic system, the relief valve: Inhibit the abnormal high pressureloop, To prevent damage to hydraulic pumps and motors, And to prevent overload in the state.2. Luffing crane safety devices: When the unexpected incident occurs, Boom luffing cylinder high-pressure hose or loop or cut off when the pipeburst, Balancing valve in the hydraulic circuit to work, Lock chamber from the fuel tank of the work under the oil The boom will not fall To ensure job security.3. Telescopic crane safety devices: When the unexpected incidentoccurs, Telescopic boom cylinder high-pressure hose or loop or cut off when the pipe burst, Balancing valve in the hydraulic circuit to work, Lock chamber from the fuel tank of the work under the oil Retracted to hang on their own, To ensure job security.4. Height limit device: Rose from under hook height, Touch the limit hammer, Open limit switch, "over around" indicator light is bright, At the same time cut off the hook lifting, Boom out, V to the other movements the crane operation and ensure safety. Then as long as the manipulation of hookdrop Boom boom retracted or looked up (ie safe side operation) so thehandle, Lift the constraints that limit a heavy hammer, Returned to normal operation. For special occasions, If still needs to be over around the operation ofmicro, Press the release button on the meter box, The role of time limit will be lifted, But this time the operation must be very careful, In case something happensSo.5. Outrigger locking device: When the unexpected incident occurs, Leading to the leg vertical cylinder high-pressure hose or pipe rupture or cutting, Two-way hydraulic system hydraulic lock cylinder block to block the two legs of the pressureoil chamber, Indented or throw the legs, To ensure the safety of lifting operations.6. From the weight indicator: From the weight indicator set in the basic arm of the co-lateral side (right side of the control room), Control room operator can sit clearly observed, Can accurately indicate the condition of the crane, and the corresponding elevation to allow the rated capacity crane.7. Lifting characteristics table: In the control room set up under the siding on the front side, The table lists the various working range of arm length and rated under the weight and lifting height To operation inspection. Liftingoperations, Must not exceed the values specified in the table. In order to ensure safe and reliable lifting operation, Crane with a better safety devices To accidental circumstances, Protect or warn the operating personnel in mechanical, To play a security role.Lifting according to their functions and structural features of Can be divided into the following four categories.I. Small-sized lifting equipmentLight lifting equipment is characterized by a smalllight, Compact Movements are simple, Operating range projection of a point, Line-based. Light, Small lifting equipment, generally only one elevator, It only。

附录外文文献原文：The Introduction of cranesA crane is defined as a mechanism for lifting and lowering loads with a hoisting mechanism Shapiro, 1991. Cranes are the most useful and versatile piece of equipment on a vast majority of construction projects. They vary widely in configuration, capacity, mode of operation, intensity of utilization and cost. On a large project, a contractor may have an assortment of cranes for different purposes. Small mobile hydraulic cranes may be used for unloading materials from trucks and for small concrete placement operations, while larger crawler and tower cranes may be used for the erection and removal of forms, the installation of steel reinforcement, the placement of concrete, and the erection of structural steel and precast concrete beams.On many construction sites a crane is needed to lift loads such as concrete skips, reinforcement, and formwork. As the lifting needs of the construction industry have increased and diversified, a large number of general and special purpose cranes have been designed and manufactured. These cranes fall into two categories, those employed in industry and those employed in construction. The most common types of cranes used in construction are mobile, tower, and derrick cranes.1.Mobile cranesA mobile crane is a crane capable of moving under its own power without being restricted to predetermined travel. Mobility is provided by mounting or integrating the crane with trucks or all terrain carriers or rough terrain carriers or by providing crawlers. Truck-mounted cranes have the advantage of being able to move under their own power to the construction site. Additionally, mobile cranes can move about the site, and are often able to do the work of several stationary units.Mobile cranes are used for loading, mounting, carrying large loads and for work performed in the presence of obstacles of various kinds such as power lines and similar technological installations. The essential difficulty is here the swinging of the payload which occurs during working motion and also after the work is completed. This applies particularly to the slewing motion of the crane chassis, for which relatively large angular accelerations and negative accelerations of the chassis are characteristic. Inertia forces together with the centrifugal force and the Carioles force cause the payload to swing as a spherical pendulum. Proper control of the slewing motion of the crane serving to transport a payload to the defined point with simultaneous minimization of the swings when theworking motion is finished plays an important role in the model.Modern mobile cranes include the drive and the control systems. Control systems send the feedback signals from the mechanical structure to the drive systems. In general, they are closed chain mechanisms with flexible members [1].Rotation, load and boom hoisting are fundamental motions the mobile crane. During transfer of the load as well as at the end of the motion process, the motor drive forces, the structure inertia forces, the wind forces and the load inertia forces can result in substantial, undesired oscillations in crane. The structure inertia forces and the load inertia forces can be evaluated with numerical methods, such as the finite element method. However, the drive forces are difficult to describe. During start-up and breaking the output forces of the drive system significantly fluctuate. To reduce the speed variations during start-up and braking the controlled motor must produce torque other than constant [2,3], which in turn affects the performance of the crane.Modern mobile cranes that have been built till today have oft a maximal lifting capacity of 3000 tons and incorporate long booms. Crane structure and drive system must be safe, functionary and as light as possible. For economic and time reasons it is impossible to build prototypes for great cranes. Therefore, it is desirable to determinate the crane dynamic responses with the theoretical calculation.Several published articles on the dynamic responses of mobile crane are available in the open literature. In the mid-seventies Peeken et al. [4] have studied the dynamic forces of a mobile crane during rotation of the boom, using very few degrees of freedom for the dynamic equations and very simply spring-mass system for the crane structure. Later Maczynski et al. [5] studied the load swing of a mobile crane with a four mass-model for the crane structure. Posiadala et al. [6] have researched the lifted load motion with consideration for the change of rotating, booming and load hoisting. However, only the kinematics were studied. Later the influence of the flexibility of the support system on the load motion was investigated by the same author [7]. Recently, Kilicaslan et al. [1] have studied the characteristics of a mobile crane using a flexible multibody dynamics approach. Towarek [16] has concentrated the influence of flexible soil foundation on the dynamic stability of the boom crane. The drive forces, however, in all of those studies were presented by using so called the metho d of ……kinematics forcing‟‟ [6] with assumed velocities or accelerations. In practice this assumption could not comply with the motion during start-up and braking.A detailed and accurate model of a mobile crane can be achieved with the finite element method. Using non-linear finite element theory Gunthner and Kleeberger [9] studied the dynamic responses of lattice mobile cranes. About 2754 beam elements and 80 truss elements were used for modeling of the lattice-boom structure. On this basis a efficient software for mobile crane calculation––NODYA has been developed. However, the influences of the drive systems must be determined by measuring on hoisting of the load[10], or rotating of the crane [11]. This is neither efficient nor convenient for computer simulation of arbitrary crane motions.Studies on the problem of control for the dynamic response of rotary crane are also available. Sato et al. [14], derived a control law so that the transfer a load to a desired position will take place that at the end of the transfer of the swing of the load decays as soon as possible. Gustafsson [15] described a feedback control system for a rotary crane to move a cargo without oscillations and correctly align the cargo at the final position. However, only rigid bodies and elastic joint between the boom and the jib in those studies were considered. The dynamic response of the crane, for this reason, will be global.To improve this situation, a new method for dynamic calculation of mobile cranes will be presented in this paper. In this method, the flexible multibody model of the steel structure will be coupled with the model of the drive systems. In that way the elastic deformation, the rigid body motion of the structure and the dynamic behavior of the drive system can be determined with one integrated model. In this paper this method will be called ……complete dynamic calculation for driven “mechanism”.On the basis of flexible multibody theory and the Lagrangian equations, the system equations for complete dynamic calculation will be established. The drive- and control system will be described as differential equations. The complete system leads to a non-linear system of differential equations. The calculation method has been realized for a hydraulic mobile crane. In addition to the structural elements, the mathematical modeling of hydraulic drive- and control systems is decried. The simulations of crane rotations for arbitrary working conditions will be carried out. As result, a more exact representation of dynamic behavior not only for the crane structure, but also for the drive system will be achieved. Based on the results of these simulations the influences of the accelerations, velocities during start-up and braking of crane motions will be discussed.2.Tower cranesThe tower crane is a crane with a fixed vertical mast that is topped by a rotating boom and equipped with a winch for hoisting and lowering loads (Dickie, 990). Tower cranes are designed for situations which require operation in congested areas. Congestion may arise from the nature of the site or from the nature of the construction project. There is no limitation to the height of a high-rise building that can be constructed with a tower crane. The very high line speeds, up to 304.8 mrmin, available with some models yield good production rates at any height. They provide a considerable horizontal working radius, yet require a small work space on the ground (Chalabi, 1989). Some machines can also operate in winds of up to 72.4 km/h, which is far above mobile crane wind limits.The tower cranes are more economical only for longer term construction operations and higher lifting frequencies. This is because of the fairly extensive planning needed for installation, together with the transportation, erection and dismantling costs.3. Derrick cranesA derrick is a device for raising, lowering, and/or moving loads laterally. The simplest form of the derrick is called a Chicago boom and is usually installed by being mounted to building columns or frames during or after construction (Shapiro and Shapiro, 1991).This derrick arrangement. (i.e., Chicago boom) becomes a guy derrick when it is mounted to a mast and a stiff leg derrick when it is fixed to a frame.The selection of cranes is a central element of the life cycle of the project. Cranes must be selected to satisfy the requirements of the job. An appropriately selected crane contributes to the efficiency, timeliness, and profitability of the project. If the correct crane selection and configuration is not made, cost and safety implications might be created (Hanna, 1994). Decision to select a particular crane depends on many input parameters such as site conditions, cost, safety, and their variability. Many of these parameters are qualitative, and subjective judgments implicit in these terms cannot be directly incorporated into the classical decision making process. One way of selecting crane is achieved using fuzzy logic approach.Cranes are not merely the largest, the most conspicuous, and the most representative equipment of construction sites but also, at various stages of the project, a real “bottleneck” that slows the pace of the construction process. Although the crane can be found standing idle in many instances, yet once it is involved in a particular task ,it becomes an indispensable link in the activity chain, forcing at least two crews(in the loading and the unloading zones) to wait for the service. As analyzed in previous publications [6-8] it is feasible to automate (or, rather, semi-automate) crane navigation in order to achieve higher productivity, better economy, and safe operation. It is necessary to focus on the technical aspects of the conversion of existing crane into large semi-automatic manipulators. By mainly external devices mounted on the crane, it becomes capable of learning, memorizing, and autonomously navigation to reprogrammed targets or through prêt aught paths.The following sections describe various facets of crane automation:First, the necessary components and their technical characteristics are reviewed, along with some selection criteria. These are followed by installation and integration of the new components into an existing crane. Next, the Man –Machine –Interface (MMI) is presented with the different modes of operation it provides. Finally, the highlights of a set of controlled tests are reported followed by conclusions and recommendations.Manual versus automatic operation: The three major degrees of freedom of common tower cranes are illustrated in the picture. In some cases , the crane is mounted on tracks , which provide a fourth degree of freedom , while in other cases the tower is “telescope” or extendable , and /or the “jib” can be raised to a diagonal position. Since these additional degrees of freedom are not used routinely during normal operation but rather are fixed in a certain position for long periods (days or weeks), they are not included in the routineautomatic mode of operation, although their position must be “known” to the control system.外文文献中文翻译：起重机介绍起重机是用来举升机构、抬起或放下货物的器械。

起重机中英⽂对照外⽂翻译⽂献中英⽂对照外⽂翻译(⽂档含英⽂原⽂和中⽂翻译)Control of Tower Cranes WithDouble-Pendulum Payload DynamicsAbstract：The usefulness of cranes is limited because the payload is supported by an overhead suspension cable that allows oscilation to occur during crane motion. Under certain conditions, the payload dynamics may introduce an additional oscillatory mode that creates a double pendulum. This paper presents an analysis of this effect on tower cranes. This paper also reviews a command generation technique to suppress the oscillatory dynamics with robustness to frequency changes. Experimental results are presented to verify that the proposed method can improve the ability of crane operators to drive a double-pendulum tower crane. The performance improvements occurred during both local and teleoperated control.Key words：Crane , input shaping , tower crane oscillation , vibrationI. INTRODUCTIONThe study of crane dynamics and advanced control methods has received significant attention. Cranes can roughly be divided into three categories based upontheir primary dynamic properties and the coordinate system that most naturally describes the location of the suspension cable connection point. The first category, bridge cranes, operate in Cartesian space, as shown in Fig. 1(a). The trolley moves along a bridge, whose motion is perpendicular to that of the trolley. Bridge cranes that can travel on a mobile base are often called gantry cranes. Bridge cranes are common in factories, warehouses, and shipyards.The second major category of cranes is boom cranes, such as the one sketched in Fig. 1(b). Boom cranes are best described in spherical coordinates, where a boom rotates aboutaxes both perpendicular and parallel to the ground. In Fig. 1(b), ψis the rotation aboutthe vertical, Z-axis, and θis the rotation about the horizontal, Y -axis. The payload is supported from a suspension cable at the end of the boom. Boom cranes are often placed on a mobile base that allows them to change their workspace.The third major category of cranes is tower cranes, like the one sketched in Fig. 1(c). These are most naturally described by cylindrical coordinates. A horizontal jib arm rotates around a vertical tower. The payload is supported by a cable from the trolley, which moves radially along the jib arm. Tower cranes are commonly used in the construction of multistory buildings and have the advantage of having a small footprint-to-workspace ratio. Primary disadvantages of tower and boom cranes, from a control design viewpoint, are the nonlinear dynamics due to the rotational nature of the cranes, in addition to the less intuitive natural coordinate systems.A common characteristic among all cranes is that the pay- load is supported via an overhead suspension cable. While this provides the hoisting functionality of the crane, it also presents several challenges, the primary of which is payload oscillation. Motion of the crane will often lead to large payload oscillations. These payload oscillations have many detrimental effects including degrading payload positioning accuracy, increasing task completion time, and decreasing safety. A large research effort has been directed at reducing oscillations. An overview of these efforts in crane control, concentrating mainly on feedback methods, is provided in [1]. Some researchers have proposed smooth commands to reduce excitation of system flexible modes [2]–[5]. Crane control methods based on command shaping are reviewed in [6]. Many researchers have focused on feedback methods, which necessitate the addition necessitate the addition of sensors to the crane and can prove difficult to use in conjunction with human operators. For example, some quayside cranes have been equipped with sophisticated feedback control systems to dampen payload sway. However, the motions induced by the computer control annoyed some of the human operators. As a result, the human operators disabled the feedback controllers. Given that the vast majority of cranes are driven by human operators and will never be equipped with computer-based feedback, feedback methods are not considered in this paper.Input shaping [7], [8] is one control method that dramatically reduces payload oscillation by intelligently shaping the commands generated by human operators [9], [10]. Using rough estimates of system natural frequencies and damping ratios, a series of impulses, called the input shaper, is designed. The convolution of the input shaper and the original command is then used to drive the system. This process is demonstrated with atwo-impulse input shaper and a step command in Fig. 2. Note that the rise time of the command is increased by the duration of the input shaper. This small increase in the rise time isnormally on the order of 0.5–1 periods of the dominant vibration mode.Fig. 1. Sketches of (a) bridge crane, (b) boom crane, (c) and tower crane.Fig. 2. Input-shaping process.Input shaping has been successfully implemented on many vibratory systems including bridge [11]–[13], tower [14]–[16], and boom [17], [18] cranes, coordinate measurement machines[19]–[21], robotic arms [8], [22], [23], demining robots [24], and micro-milling machines [25].Most input-shaping techniques are based upon linear system theory. However, some research efforts have examined the extension of input shaping to nonlinear systems [26], [14]. Input shapers that are effective despite system nonlinearities have been developed. These include input shapers for nonlinear actuator dynamics, friction, and dynamic nonlinearities [14], [27]–[31]. One method of dealing with nonlinearities is the use of adaptive or learning input shapers [32]–[34].Despite these efforts, the simplest and most common way to address system nonlinearities is to utilize a robust input shaper [35]. An input shaper that is more robust to changes in system parameters will generally be more robust to system nonlinearities that manifest themselves as changes in the linearized frequencies. In addition to designing robust shapers, input shapers can also be designed to suppress multiple modes of vibration [36]–[38].In Section II, the mobile tower crane used during experimental tests for this paper is presented. In Section III, planar and 3-D models of a tower crane are examined to highlight important dynamic effects. Section IV presents a method to design multimode input shapers with specified levels of robustness. InSection V, these methods are implemented on a tower crane with double-pendulum payload dynamics. Finally, in Section VI, the effect of the robust shapers on human operator performance is presented for both local and teleoperated control.II. MOBILE TOWER CRANEThe mobile tower crane, shown in Fig. 3, has teleoperation capabilities that allow it to be operated in real-time from anywhere in the world via the Internet [15]. The tower portion of the crane, shown in Fig. 3(a), is approximately 2 m tall with a 1 m jib arm. It is actuated by Siemens synchronous, AC servomotors. The jib is capable of 340°rotation about the tower. The trolley moves radially along the jib via a lead screw, and a hoisting motor controls the suspension cable length. Motor encoders are used for PD feedback control of trolley motion in the slewing and radial directions. A Siemens digital camera is mounted to the trolley and records the swing deflection of the hook at a sampling rate of 50 Hz [15].The measurement resolution of the camera depends on the suspension cable length. For the cable lengths used in this research, the resolution is approximately 0.08°. This is equivalent to a 1.4 mm hook displacement at a cable length of 1 m. In this work, the camera is not used for feedback control of the payload oscillation. The experimental results presented in this paper utilize encoder data to describe jib and trolley position and camera data to measure the deflection angles of the hook. Base mobility is provided by DC motors with omnidirectional wheels attached to each support leg, as shown in Fig. 3(b). The base is under PD control using two HiBot SH2-based microcontrollers, with feedback from motor-shaft-mounted encoders. The mobile base was kept stationary during all experiments presented in this paper. Therefore, the mobile tower crane operated as a standard tower crane.Table I summarizes the performance characteristics of the tower crane. It should be noted that most of these limits areenforced via software and are not the physical limitations of the system. These limitations are enforced to more closely match theoperational parameters of full-sized tower cranes.Fig. 3. Mobile, portable tower crane, (a) mobile tower crane, (b) mobile crane base.TABLE I MOBILE TOWER CRANE PERFORMANCE LIMITSFig. 4 Sketch of tower crane with a double-pendulum dynamics.III. TOWER CRANE MODELFig.4 shows a sketch of a tower crane with a double-pendulum payload configuration. The jib rotates by an angle around the vertical axis Z parallelto the tower column. The trolley moves radially along the jib; its position along the jib is described by r . The suspension cable length from the trolley to the hook is represented by an inflexible, massless cable of variable length 1l . The payload is connected to the hook via an inflexible, massless cable of length 2l . Both the hook and the payload are represented as point masses having masses h m and p m , respectively.The angles describing the position of the hook are shown in Fig. 5(a). The angle φrepresents a deflection in the radial direction, along the jib. The angle χ represents a tangential deflection, perpendicular to the jib. In Fig. 5(a), φ is in the plane of the page, and χ lies in a plane out of the page. The angles describing the payload position are shown in Fig. 5(b). Notice that these angles are defined relative to a line from the trolley to the hook. If there is no deflection of the hook, then the angleγ describes radial deflections, along the jib, and the angle α represents deflections perpendicular to the jib, in the tangential direction. The equations of motion for this model were derived using a commercial dynamics package, but they are too complex to show in their entirety here, as they are each over a page in length.To give some insight into the double-pendulum model, the position of the hook and payload within the Newtonian frame XYZ are written as —h q and —p q , respectivelyWhere -I , -J and -K are unit vectors in the X , Y , and Z directions. The Lagrangian may then be written asFig. 5. (a) Angles describing hook motion. (b) Angles describing payload motion.Fig. 6. Experimental and simulated responses of radial motion.(a) Hook responses (φ) for m 48.01=l ，(b) Hook responses for m 28.11=lThe motion of the trolley can be represented in terms of the system inputs. The position of the trolley —tr q in the Newtonian frame is described byThis position, or its derivatives, can be used as the input to any number of models of a spherical double-pendulum. More detailed discussion of the dynamics of spherical double pendulums can be found in [39]–[42].The addition of the second mass and resulting double-pendulum dramatically increases the complexity of the equations of motion beyond the more commonly used single-pendulum tower model [1], [16], [43]–[46]. This fact can been seen in the Lagrangian. In (3), the terms in the square brackets represent those that remain for the single-pendulum model; no —p q terms appear. This significantly reduces the complexity of the equations because —p q is a function of the inputs and all four angles shown in Fig. 5.It should be reiterated that such a complex dynamic model is not used to design the input-shaping controllers presented in later sections. The model was developed as a vehicle to evaluate the proposed control method over a variety of operating conditions and demonstrate its effectiveness. The controller is designed using a much simpler, planar model.A. Experimental V erification of the ModelThe full, nonlinear equations of motion were experimentally verified using several test cases. Fig.6 shows two cases involving only radial motion. The trolley was driven at maximum velocity for a distance of 0.30 m, with 2l =0.45m .The payload mass p m for both cases was 0.15 kg and the hook mass h m was approximately 0.105 kg. The two cases shown in Fig. 6 present extremes of suspension cable lengths 1l . In Fig. 6(a), 1l is 0.48 m , close to the minimum length that can be measured by the overhead camera. At this length, the double-pendulum effect is immediately noticeable. One can see that the experimental and simulated responses closely match. In Fig. 6(b), 1l is 1.28 m, the maximum length possible while keeping the payload from hitting the ground. At this length, the second mode of oscillation has much less effect on the response. The model closely matches the experimental response for this case as well. The responses for a linearized, planar model, which will be developed in Section III-B, are also shown in Fig. 6. The responses from this planar model closely match both the experimental results and the responses of the full, nonlinear model for both suspension cable lengths.Fig. 7. Hook responses to 20°jib rotation:(a) φ (radial) response;(b) χ (tangential) response.Fig. 8. Hook responses to 90°jib rotation:φ(radial) response;(b) χ(tangential) response.(a)If the trolley position is held constant and the jib is rotated, then the rotational and centripetal accelerations cause oscillation in both the radial and tangential directions. This can be seen in the simulation responses from the full nonlinear model in Figs. 7 and 8. In Fig. 7, the trolley is held at a fixed position of r = 0.75 m, while the jib is rotated 20°. This relatively small rotation only slightly excites oscillation in the radial direction, as shown in Fig. 7(a). The vibratory dynamics are dominated byoscillations in the tangential direction, χ, as shown in Fig. 7(b). If, however, a large angular displacement of the jib occurs, then significant oscillation will occur in both the radial and tangential directions, as shown in Fig. 8. In this case, the trolley was fixed at r = 0.75 m and the jib was rotated 90°. Figs. 7 and 8 show that the experimental responses closely match those predicted by the model for these rotational motions. Part of the deviation in Fig. 8(b) can be attributed to the unevenness of the floor on which the crane sits. After the 90°jib rotation the hook and payload oscillate about a slightly different equilibrium point, as measured by the overhead camera.Fig.9.Planardouble-pendulummodel.B.Dynamic AnalysisIf the motion of the tower crane is limited to trolley motion, like the responses shown in Fig. 6, then the model may be simplified to that shown in Fig. 9. This model simplifies the analysis of the system dynamics and provides simple estimates of the two natural frequencies of the double pendulum. These estimates will be used to develop input shapers for the double-pendulum tower crane.The crane is moved by applying a force )(t u to the trolley. A cable of length 1l hangs below the trolley and supports a hook, of mass h m , to which the payload is attached using rigging cables. The rigging and payload are modeled as a second cable, of length 2l and point mass p m . Assuming that the cable and rigging lengths do not change during the motion, the linearized equations of motion, assuming zero initial conditions, arewhere φ and γ describe the angles of the two pendulums, R is the ratio of the payload mass to the hook mass, and g is the acceleration due to gravity.The linearized frequencies of the double-pendulum dynamics modeled in (5) are [47]Where Note that the frequencies depend on the two cable lengths and the mass ratio.Fig. 10. Variation of first and second mode frequencies when m l l 8.121=+.。

外文资料翻译译文塔式起重机动臂装在高耸塔身上部的旋转起重机。

作业空间大，主要用于房屋建筑施工中物料的垂直和水平输送及建筑构件的安装。

由金属结构、工作机构和电气系统三部分组成。

金属结构包括塔身、动臂和底座等。

工作机构有起升、变幅、回转和行走四部分。

电气系统包括电动机、控制器、配电柜、连接线路、信号及照明装置等。

塔式起重机简称塔机，亦称塔吊，起源于西欧。

据记载，第一项有关建筑用塔机专利颁发于1900 年。

1905 年出现了塔身固定的装有臂架的起重机，1923 年制成了近代塔机的原型样机，同年出现第一台比较完整的近代塔机。

1930 年当时德国已开始批量生产塔机，并用于建筑施工。

1941 年，有关塔机的德国工业标准DIN8770 公布。

该标准规定以吊载(t)和幅度(m)的乘积(tm)一起以重力矩表示塔机的起重能力。

我国的塔机行业于20 世纪50 年代开始起步,相对于中西欧国家由于建筑业疲软造成的塔机业的不景气, 上海波赫驱动系统有限公司我国的塔机业正处于一个迅速的发展时期。

从塔机的技术发展方面来看，虽然新的产品层出不穷，新产品在生产效能、操作简便、保养容易和运行可靠方面均有提高，但是塔机的技术并无根本性的改变。

塔机的研究正向着组合式发展。

所谓的组合式，就是以塔身结构为核心，按结构和功能特点，将塔身分解成若干部分，并依据系列化和通用化要求，遵循模数制原理再将各部分划分成若干模块。

根据参数要求，选用适当模块分别组成具有不同技术性能特征的塔机，以满足施工的具体需求。

推行组合式的塔机有助于加快塔机产吕开发进度，节省产品开发费用，并能更好的为客户服务。

塔机分为上回转塔机和下回转塔机两大类。

其中前者的承载力要高于后者，在许多的施工现场我们所见到的就是上回转式上顶升加节接高的塔机。

按能否移动又分为：走行式和固定式。

固定式塔机塔身固定不转，安装在整块混凝土基础上，或装设在条形式X 形混凝土基础上。

在房屋的施工中一般采用的是固定式的。

附录外文文献原文：The Introduction of cranesA crane is defined as a mechanism for lifting and lowering loads with a hoisting mechanism Shapiro, 1991. Cranes are the most useful and versatile piece of equipment on a vast majority of construction projects. They vary widely in configuration, capacity, mode of operation, intensity of utilization and cost. On a large project, a contractor may have an assortment of cranes for different purposes. Small mobile hydraulic cranes may be used for unloading materials from trucks and for small concrete placement operations, while larger crawler and tower cranes may be used for the erection and removal of forms, the installation of steel reinforcement, the placement of concrete, and the erection of structural steel and precast concrete beams.On many construction sites a crane is needed to lift loads such as concrete skips, reinforcement, and formwork. As the lifting needs of the construction industry have increased and diversified, a large number of general and special purpose cranes have been designed and manufactured. These cranes fall into two categories, those employed in industry and those employed in construction. The most common types of cranes used in construction are mobile, tower, and derrick cranes.1.Mobile cranesA mobile crane is a crane capable of moving under its own power without being restricted to predetermined travel. Mobility is provided by mounting or integrating the crane with trucks or all terrain carriers or rough terrain carriers or by providing crawlers. Truck-mounted cranes have the advantage of being able to move under their own power to the construction site. Additionally, mobile cranes can move about the site, and are often able to do the work of several stationary units.Mobile cranes are used for loading, mounting, carrying large loads and for work performed in the presence of obstacles of various kinds such as power lines and similar technological installations. The essential difficulty is here the swinging of the payload which occurs during working motion and also after the work is completed. This applies particularly to the slewing motion of the crane chassis, for which relatively large angular accelerations and negative accelerations of the chassis are characteristic. Inertia forces together with the centrifugal force and the Carioles force cause the payload to swing as a spherical pendulum. Proper control of the slewing motion of the crane serving to transport a payload to the defined point with simultaneous minimization of the swings when theworking motion is finished plays an important role in the model.Modern mobile cranes include the drive and the control systems. Control systems send the feedback signals from the mechanical structure to the drive systems. In general, they are closed chain mechanisms with flexible members [1].Rotation, load and boom hoisting are fundamental motions the mobile crane. During transfer of the load as well as at the end of the motion process, the motor drive forces, the structure inertia forces, the wind forces and the load inertia forces can result in substantial, undesired oscillations in crane. The structure inertia forces and the load inertia forces can be evaluated with numerical methods, such as the finite element method. However, the drive forces are difficult to describe. During start-up and breaking the output forces of the drive system significantly fluctuate. To reduce the speed variations during start-up and braking the controlled motor must produce torque other than constant [2,3], which in turn affects the performance of the crane.Modern mobile cranes that have been built till today have oft a maximal lifting capacity of 3000 tons and incorporate long booms. Crane structure and drive system must be safe, functionary and as light as possible. For economic and time reasons it is impossible to build prototypes for great cranes. Therefore, it is desirable to determinate the crane dynamic responses with the theoretical calculation.Several published articles on the dynamic responses of mobile crane are available in the open literature. In the mid-seventies Peeken et al. [4] have studied the dynamic forces of a mobile crane during rotation of the boom, using very few degrees of freedom for the dynamic equations and very simply spring-mass system for the crane structure. Later Maczynski et al. [5] studied the load swing of a mobile crane with a four mass-model for the crane structure. Posiadala et al. [6] have researched the lifted load motion with consideration for the change of rotating, booming and load hoisting. However, only the kinematics were studied. Later the influence of the flexibility of the support system on the load motion was investigated by the same author [7]. Recently, Kilicaslan et al. [1] have studied the characteristics of a mobile crane using a flexible multibody dynamics approach. Towarek [16] has concentrated the influence of flexible soil foundation on the dynamic stability of the boom crane. The drive forces, however, in all of those studies were presented by using so called the metho d of ……kinematics forcing‟‟ [6] with assumed velocities or accelerations. In practice this assumption could not comply with the motion during start-up and braking.A detailed and accurate model of a mobile crane can be achieved with the finite element method. Using non-linear finite element theory Gunthner and Kleeberger [9] studied the dynamic responses of lattice mobile cranes. About 2754 beam elements and 80 truss elements were used for modeling of the lattice-boom structure. On this basis a efficient software for mobile crane calculation––NODYA has been developed. However, the influences of the drive systems must be determined by measuring on hoisting of the load[10], or rotating of the crane [11]. This is neither efficient nor convenient for computer simulation of arbitrary crane motions.Studies on the problem of control for the dynamic response of rotary crane are also available. Sato et al. [14], derived a control law so that the transfer a load to a desired position will take place that at the end of the transfer of the swing of the load decays as soon as possible. Gustafsson [15] described a feedback control system for a rotary crane to move a cargo without oscillations and correctly align the cargo at the final position. However, only rigid bodies and elastic joint between the boom and the jib in those studies were considered. The dynamic response of the crane, for this reason, will be global.To improve this situation, a new method for dynamic calculation of mobile cranes will be presented in this paper. In this method, the flexible multibody model of the steel structure will be coupled with the model of the drive systems. In that way the elastic deformation, the rigid body motion of the structure and the dynamic behavior of the drive system can be determined with one integrated model. In this paper this method will be called ……complete dynamic calculation for driven “mechanism”.On the basis of flexible multibody theory and the Lagrangian equations, the system equations for complete dynamic calculation will be established. The drive- and control system will be described as differential equations. The complete system leads to a non-linear system of differential equations. The calculation method has been realized for a hydraulic mobile crane. In addition to the structural elements, the mathematical modeling of hydraulic drive- and control systems is decried. The simulations of crane rotations for arbitrary working conditions will be carried out. As result, a more exact representation of dynamic behavior not only for the crane structure, but also for the drive system will be achieved. Based on the results of these simulations the influences of the accelerations, velocities during start-up and braking of crane motions will be discussed.2.Tower cranesThe tower crane is a crane with a fixed vertical mast that is topped by a rotating boom and equipped with a winch for hoisting and lowering loads (Dickie, 990). Tower cranes are designed for situations which require operation in congested areas. Congestion may arise from the nature of the site or from the nature of the construction project. There is no limitation to the height of a high-rise building that can be constructed with a tower crane. The very high line speeds, up to 304.8 mrmin, available with some models yield good production rates at any height. They provide a considerable horizontal working radius, yet require a small work space on the ground (Chalabi, 1989). Some machines can also operate in winds of up to 72.4 km/h, which is far above mobile crane wind limits.The tower cranes are more economical only for longer term construction operations and higher lifting frequencies. This is because of the fairly extensive planning needed for installation, together with the transportation, erection and dismantling costs.3. Derrick cranesA derrick is a device for raising, lowering, and/or moving loads laterally. The simplest form of the derrick is called a Chicago boom and is usually installed by being mounted to building columns or frames during or after construction (Shapiro and Shapiro, 1991).This derrick arrangement. (i.e., Chicago boom) becomes a guy derrick when it is mounted to a mast and a stiff leg derrick when it is fixed to a frame.The selection of cranes is a central element of the life cycle of the project. Cranes must be selected to satisfy the requirements of the job. An appropriately selected crane contributes to the efficiency, timeliness, and profitability of the project. If the correct crane selection and configuration is not made, cost and safety implications might be created (Hanna, 1994). Decision to select a particular crane depends on many input parameters such as site conditions, cost, safety, and their variability. Many of these parameters are qualitative, and subjective judgments implicit in these terms cannot be directly incorporated into the classical decision making process. One way of selecting crane is achieved using fuzzy logic approach.Cranes are not merely the largest, the most conspicuous, and the most representative equipment of construction sites but also, at various stages of the project, a real “bottleneck” that slows the pace of the construction process. Although the crane can be found standing idle in many instances, yet once it is involved in a particular task ,it becomes an indispensable link in the activity chain, forcing at least two crews(in the loading and the unloading zones) to wait for the service. As analyzed in previous publications [6-8] it is feasible to automate (or, rather, semi-automate) crane navigation in order to achieve higher productivity, better economy, and safe operation. It is necessary to focus on the technical aspects of the conversion of existing crane into large semi-automatic manipulators. By mainly external devices mounted on the crane, it becomes capable of learning, memorizing, and autonomously navigation to reprogrammed targets or through prêt aught paths.The following sections describe various facets of crane automation:First, the necessary components and their technical characteristics are reviewed, along with some selection criteria. These are followed by installation and integration of the new components into an existing crane. Next, the Man –Machine –Interface (MMI) is presented with the different modes of operation it provides. Finally, the highlights of a set of controlled tests are reported followed by conclusions and recommendations.Manual versus automatic operation: The three major degrees of freedom of common tower cranes are illustrated in the picture. In some cases , the crane is mounted on tracks , which provide a fourth degree of freedom , while in other cases the tower is “telescope” or extendable , and /or the “jib” can be raised to a diagonal position. Since these additional degrees of freedom are not used routinely during normal operation but rather are fixed in a certain position for long periods (days or weeks), they are not included in the routineautomatic mode of operation, although their position must be “known” to the control system.外文文献中文翻译：起重机介绍起重机是用来举升机构、抬起或放下货物的器械。

附录英文原文Crane Scheduling with Spatial ConstraintsAndrew Lim, Brian Rodrigues, Fei Xiao, and Yi ZhuAbstractIn this work, we examine port crane scheduling with spatial and separation constraints. Although common to most port operations, these constraints have not been previously studied. We assume that cranes cannot cross, there is a minimum distance between cranes and jobs cannot be done simultaneously. Theobjective is to find a crane-to-job matching which maximizes throughput under these constraints. We provide dynamic programming algorithms, a probabilistic tabu search and a squeaky wheel optimization heuristic for solution. Experiments show the heuristics perform well compared with optimal solutions obtained by CPLEX for small scale instances where a squeaky wheel optimization with local search approach gives good results within short times.1 IntroductionThe Port of Singapore Authority (PSA) is a large port operator located in Singapore, one of the busiest ports in the world. PSA handles 17.04 millio n TEU’s annually or nine percent of global container traffic in Singapore, the world’s largest transshipment hub. PSA is concerned with maximizing throughput at its port due to limited port size, high cargo transshipment volumes and limited physical facilities and equipment . Crane scheduling and work schedules are critical in port management since cranes are at the interface between land and water sections of any port, each with its own traffic lanes, intersections, and vehicle flow control systems. In this mul ti-channel interface we are likely to find bottlenecks where cranes and other cargo-handling equipment (forklifts, conveyors etc.) converge.Sabria and Daganzo studied port operations which focused on berthing and cargo-handling systems. In berthing, which is a widely-analyzed port activity, queuing theory has been used widely. Traffic and vehicle-flow scheduling on land in ports has also been well studied. Danganzo studied a static crane scheduling case where cranes could move freely from hold to hold and only one crane is allowed to work on one hold at any one time.The objective was to minimize the aggregate cost of delay. In [13], container handling is modelled as ―work‖ which cranes perform at constant rates and cranes can interrupt work without loss of effici ency. This constituted an ―open shop‖ parallel and identical machines problem, where jobs consist of independent,single-stage and pre-emptable tasks. A branch- and-bound method was used to minimize delay costs for this problem. Crane scheduling has also been studied in the manufacturing environment context .Commonly-found constraints affecting crane operations are absent in studies available on the subject. Such constraints affect crane work scheduling and need to be factored into operational models. These include the basic requirement that operating cranes do not cross over each other. Also, a minimum separating distance between cranes is necessary since cranes require some spatial flexibility in performing jobs. Finally, there is a need for jobs arriving for stacking at yards to be separated in arrival time to avoid congestion.We found that operational decision-making at PSA was based largely on experience and simulation techniques. While the latter is of value, analytic models are an advantage and are not limited by experience-generated rules-of-thumbs or simulation. The object of this work is to address the need for such models which take into account common spatial and separation requirements in the scheduling cranes. This work augments Peterkofsky and Daganzo study .2 Problem DescriptionDuring the time ships are berthed, various cargo-handling equipment is used to unload cargo, mostly in the form of containers. Different types of cargo require different handling and many ports have bulk, container, dry and liquid-bulk terminals. Cargo that is containerized can be loaded and unloaded in a fewer number of moves by cranes operating directly over ship holds or by crane arms moving over holds or deck areas.Cargo stacked in yards is moved by cranes onto movers and transported for loading onto ships. ‖Cargo‖ here comprises containers of different capacities, which, whether in ships or in yards, are parcelled into fixed areas for access to cranes. For example, cargo placed in specific holds or deck sections on ships, or in sections within yards.Containers are unloaded from ships by quay cranes onto movers or trailers which carry them to assigned yard locations where they are loaded onto stacks by yard cranes. Containers destined for import are set aside, and restacking, if required, is carried out. In the movement of containers, sequencing is crucial because containers are stored in stacks in the ship and on the yard and lanes may be designated to specific trailers at certain times. In addition, the movement of containers involves routing and crane operations where timings may be uncertain. In fact, crane scheduling is one activity among many that determine the movement of containers. Other such activities includeberthing, yard storage, ship stowage and vehicle allocation and routing, all of which can be uncertain. Because of the uncertainty present over all activities, it is almost impossible to implement a plan over any length of time. This difficulty is present in scheduling cranes. For example, although a set of jobs may be assigned to a certain crane, it may not be possible for the crane to complete processing a job in this set onto movers once it was known that the route these movers are to take was congested. As another example, although we can specify that jobs bound for the same yard space are not unloaded from ships simultaneously, we cannot expect such containers to be unloaded at a time other than the allotted time interval, since a required resource to complete the job may become unavailable after this time, as for example, if the yard crane becomes unavailable. In view of the dynamically changing environment, a central control devises and maintains a job assignment plan that is periodically updated in order to coordinate operations, including crane scheduling. The system will allocate all jobs and resources periodically.In the port we studied, a job parcel can include a number of ships and a number of cranes together with jobs. Typically, there c an be up to five ships with four to seven cranes per ship and a number of jobs depending on the size and configuration of ships. Jobs have a profit value assigned to them and resources, e.g., cranes, movers, lanes etc., are assigned to each of the jobs depending on their value to the overall operations plan which aims to optimize total throughput. When an assignment plan is updated, the central system reassesses the current state of operations to regroup and reassign job parcels. Because of this, time is accommodated by constant adjustments of job parcels and assignments based on the current state of all operations. Hence, once jobs and resources are assigned for the time period no update is necessary.Jobs come in different sizes, and cranes have different handling capacities. Since we make the assumption that any crane assigned to a job completes it, the throughput or profit, for a given crane-to-job assignment, is a fixed value independent of other crane-to-job assignments.The problem is naturally represented by a bipartite graph matching problem when we take cranes and jobs to be the vertices and define the weights of connecting edges to be crane-to-job throughput. This representation is shown in Figure 1.Figure 1This matching problem is interesting because, in practice, a number of spatial constraints arise for cranes and jobs. We first introduce qualitative notions of three particularly common constraints which we call ―spatial‖ constraints since they are related to the relative posi tions of cranes and jobs. Our objective is to find a crane-to-job assignment scheme which maximizes throughput under these constraints. For reasons given above, we assume that crane-to-job assignments are performed in a given time interval, i.e., there is no temporal component in the problem. Detailed definitions will be given in the relevant sections of this paper.1. Non-crossing constraint: Cranes cannot cross over each other. This is a structural constraint on cranes and crane tracks.2. Neighborhood constraint: There is a minimum distance between cranes. This arises, for example, since cranes require flexibility in space to perform jobs and/or for safety reasons. The effect of this constraint is that neighboring jobs may be affected and may not be assignable to other cranes.3. Job-separation constraint: Certain jobs cannot be done simultaneously. For example, jobs bound for the same yard may require separation in time to avoid trailer congestion in lanes.In the following sections, we first consider these constraints separately and then simultaneously. In section 3, an O(mn) dynamic programming (DP) algorithm is given to solve the problem with only the Non-crossing constraint where m is the number of cranes and n is the number of jobs. In section 4, we use an O(m2n) dynamic programming algorithm to achieve an optimal solution for the problem with both the Non-crossing and Neighborhood constraints. In section 5, assuming all three spatial constraints, we show the problem to be NP-complete and give two heuristic approaches to solve the problem —a probabilistic tabu search and a squeaky wheel optimizationwith local search method. In section 6, we provide experimental results and compare the different approaches.3 Scheduling with the Non-Crossing Constraint3.1 The ProblemThroughout this work, C= {c1, c2, . . . , c m} is a set of cranes and J= {j1, j2, . . . , j n} a set of jobs. The order of subscripts assigned to the cranes and jobs represents their spatial (assumed linear) distribution, i.e., the neighbor of j1is j2, the neighbors of j2are j1and j3,. . . , and the neighbor of j n is j n−1, The same holds for the cranes.An m × n adjacency matrix, W , is used to represent the relationships between jobs and cranes. For each W x,y∈W , the value W x,y represents the throughput when job j y is assigned to crane c x where W x,y= 0 if job j y cannot be assigned to crane c x. The W x,y values arise from the different job sizes and crane capacities.We seek a solution set,R={(p, q )|1 ≤p≤ m, 1≤q≤n, W p,q> 0}, such that the following constraint is satisfied: For all (p1, q1), (p2, q2)∈R, p1< p2if and only if q1< q2. Viewing p’s and q’s, as subscripts in C and J respectively, we see that any crane-job assignment in R satisfies the Non-crossing Constraint.The objective is then to find a set R which maximizes ∑(p,q)∈rWp,q subject to the constraints that each job is assigned to at most one crane and each crane is assigned to at most one job.3.2 Algorithm DescriptionWe now provide a dynamic programming (DP) approach and describe how to characterize an optimal solution. DP procedures for computing values of solutions in a bottom-up way and for constructing solutions from computed information are omitted since they follow directly and are required only in implementation.3.2.1 The Structure and Value of an Optimal SolutionWe consider the cranes one by one. For each crane c x, we assign every job j y(1 ≤ y ≤ n) to it and compute the total throughput to derive a partial optimal solution P x,y which denotes the optimal value up to the step we assign job j y to crane c x. Here, it is not necessary that job j y is actually assigned to crane c x, i.e., (x, y) ∈R x,y may not hold, where R x,y is the partial solution set corresponding to the partial optimal solution P x,y.The following computes the partial optimal solution, P x,y, recursively, for the different cases:1. If x = 1 and y = 1, P1，1:= W1，12. If x = 1 and y > 1, P1,y:= max{W1，y’, P1,y-1}3. If x > 1 and y = 1, P x，1:= max{W x,1, P x-1,1 }4. If x > 1 and y > 1, P x,y:= max{P x,y-1,P x-1,y’ ,P x-1,y-1+W x,y}(1) is the basic case: If we only consider the first crane and the first job,we will assign this job to the crane if the job can be done by the crane. (2) and (3) are both special cases, i.e., when there is only one node in each part of the bipartite graph. As these are symmetrical, we need consider only (2). For crane c1and job j y, we have two choices: either, assign j y to c1, or, assign a job from {j1, . . . , j y−1}to c1. This is because at most one job can be assigned to this first crane. The throughput for the first choice is W1,y while the throughput for the second choice is P1,y−1 , which represents the maximum throughput if we assign a job among j1, j2, . . . , j y-1to crane c1. To achieve the cumulative optimal, we choose the larger of these. (4) is the general case in the DP algorithm. For c x and job j y(x > 1, y > 1), we have three choices:•Leave job j y unassigned . We are reduced to assigning cranes c1, c2, . . . , c x to jobs j1, j2, . . . , j y-1. By induction, the optimal value is then P x,y-1;•Leave crane c x unassigned . We are reduced to assigning cranes c1, c2, . . . , c x-1 to jobs j1, j2, . . . , j y. By induction, the optimal value is then P x-1,y;•Assign crane c x to job j y(or, leave both unassigned if they are not assignable to each other). In this case, the total throughput is the throughput from this assignment plus the throughput from assigning cranes c1, c2, . . . , c x-1 to jobs j1, j2, . . . , j y-1. Hence, the value is P x-1,y-1+W x,y.Taking the maximum of these throughput values, the optimal solution is then the final partial optimal solution P m,n obtained.3.2.2 A Proof of Optimal SubstructureWe provide an outline a proof that the problem defined in this section possesses optimal substructures necessary in using DP. An important property for P x,y is: P x,y≥P x’,y’,if x ≥ x’and y ≥ y’(*), which is easily verified since P x,y≥ P x,y-1 and P x,y≥ P x-1,y. We can now verify the four cases given above by induction:1. If x = 1 and y = 1, clearly P1,y = W x,1 is the only solution and must be optimal2. If (x, y)∈R’x,y, then P x,y’≤P ak-1,bk-1+W x,y. By (*), we know P x-1,y−1≥P ak-1,b-1since x − 1 ≥ ak-1, y-1 ≥ bk-1. So P x,y’≤ P x-1,y-1+W x,y. Because P x,y≥P x-1,y-1+ W x,y, we get P x,y≥ P x,y’ , which contradicts our assumption P x,y’> P x,y. Hence, P x,y is the optimal solution.We can conclude that P x,y is the optimal solution for all (x, y), 1 ≤ x ≤ m, 1 ≤ y ≤ n,3.3 The Time Complexity of the AlgorithmThe computation for every partial solution P x,y is in constant time, so the time complexity for this algorithm is O(mn).4 Scheduling with the Neighborhood Constraint4.1 The ProblemIn this problem, both the Non-crossing constraint and the Neighborhood constraint are considered. In addition to the Non-crossing constraint, we use the set S= {s1, s2, . . . , s m} to represent the Neighborhood constraint associated with the cranes. Here s x= k if crane c x performs job j y and job j z(a ≤ z ≤ b, z= y) cannot be worked on by any other crane, where a = max{1, y − k}and b = min{y + k, m}. In other words, if crane c x performs job j y, the job ―interval‖ centered at y with length 2k + 1 is affected by crane c x when s x= k.We seek a solution set R = {(p, q)|1 ≤ p ≤ m, 1 ≤ q ≤ n, W p,q> 0} satisfying:1. For all (p1, q1), (p2, q2) ∈ R, p1< p2if and only if q1< q2(Non-crossing constraint)2. For all (p, q) ∈R, if 1 ≤ p’≤ m and p’= p, and a ≤ q’≤ b, where a = max{1, q − s p} and b = min{q + s p, n}, then (p’, q’) ∈R (Neighborhood constraint)Our objective is to find R that maximizes the total weight ∑(p,q)∈rWp,q where each job is assigned to at most one crane and each crane is assigned to at most one job.4.2 Algorithm DescriptionWe follow the approach in section 3.2 here.4.2.1 The Structure and Value of an Optimal SolutionWe continue to consider the cranes one by one. For each crane c x, we attempt to assign every job j y(1 ≤ y ≤ n) to it and compute the total throughput up to this step to give a partial optimal solution P x,y.Here, the partial optimal solution P x,y is cumulative and the edge inclusion (x, y) ∈R x,y may not hold. However, different from the definition used in the previous section, crane x must be assigned some job j (1 ≤ j ≤ y) for P x,y, i.e., there must be an edge (x, j) ∈R x,y, where (1 ≤ j≤ y); if there is no job in the interval [1, y] that can be assigned to crane x, then P x,y= 0. Now, we define the value of the partial optimal solution P x,y for the different cases:1. If x = 1 and y = 1, P1,1＝W1,12. If x = 1 and y > 1, P1,y:= max{W1,y,P1,y-1}3. If x > 1 and y = 1, P x,1=W x,14. If x > 1 and y > 1, P x,y:= max{P x,y-1,P i,c+W x,y}, 1 ≤ i < x, c = y− max{s x, s i} − 1.(1) is the basic case and (2) and (3) are the special cases. (2) has been explained in the previous section. (3) is different. Since we require for P x,y that crane c x must be assigned job j y, we have no choice but to assign this job to the current crane when there is only job available. The induction step in (4) is somewhat comple x. In the first case, we keep job j y unassigned, so we are reduced to assigning cranes c1, c2, . . . , c x to jobs j1, j2, . . . , j y; hence, we obtain P x,y-1. In the second case, since we assigned job j y to crane c x, the Neighborhood constraint for c x must be considered. Also, we must consider the Neighborhood constraint for the cranes c1, c2, . . . , c x which are assigned to jobs. The Non-crossing constraint simplifies the computation leaving us only to check the neighborhood constraint for the ―largest label‖crane assigned and is the reason the c value is needed in the formula.The final optimal is the maximum value of all partial optimal solutions obtained,i.e., it is max{P x,y} over all (x, y), 1 ≤ x ≤ m, 1 ≤ y ≤ n.4.2.2 A Proof of Optimal SubstructureSimilar to the earlier problem, we show that this problem has an optimal substructure. As before, we use the fact that P x,y≥ P x,y’ if y ≥ y’(**). This is easy to verify since a partial optimal solution is cumulative for each crane x. As before, we have the following cases:1. If x = 1 and y = 1, clearly P1,1= W1,1is the optimal solution2. If x = 1 and y > 1, only one crane is involved, so the Neighborhood constraint does not take the effect. The proof is then as given in the previous section3. If x > 1 and y = 1, since crane c x has to be assigned a job, and there is only one job, clearly P x,1 = W x,14. If x > 1 and y > 1, P x,y= max{P x,y-1, P i,c+ W x,y}, 1 ≤ i < x, c = y−max{s x, s i} − 1. We assume there is an optimal solution P x,y0> P x,y and the solution set corresponding to P x,y’is R’x,y={(c a1, j b1), (c a2,j b2), . . . , (c ak,j bk)}. Here, we can take this set to be ordered, i.e., a1≤ a2≤ . . . ≤ a k and b1≤ b2≤ . . . ≤ b k, by virtue of the Non-crossing constraint. Noting a k= x from the definition above, there are now two possibilities for P x,y’:(a) If (x, y) ∈R’x,y, then P x,y’≤ P ak,bk, since P ak,bk is the partial optimal solution. Hence, P x,y’≤ P x,bk, since a k= x. From property (**), we know P x,y-1≥ P x,bk since y − 1 ≥ b k(job j y is unassigned). So P x,y−1 ≥ P x,y’. By the recursive definition, P x,y≥ P x,y-1. Hence, we get P x,y≥ P x,y’, which contradicts the assumption P x,y’ > P x,y. So P x,y is the optimal solution in this case(b) If (x, y ) ∈ R’x,y, then P x,y’≤ P ak-1,bk-1+W x,y, since P ak-1,bk-1is the partial optimalsolution. Obviously 1 ≤ a k-1<x, so we let i = a k-1and c = y−max{s x, s i} − 1. We know bk−1≤c since the cranes c x andc i are both assigned jobs and their Neighborhood constraints are in effect. From (**), we get P i,c≥ P i,bk-1because of c ≥ b k−1, i.e., P ak-1,c + W x,y≥ P ak-1,bk-1,+W x,y, and so P ak-1,c+W x,y≥P x,y’. From the defini tion P x,y= max{P x,y-1,Pi,c+W x,y}, we know P x,y≥ P x,y’ , which contradicts the assumption P x,y’> Px,y. Hence, P x,y must be the optimal solution in this caseWe conclude that P x,y is the optimal solution for all (x, y), 1 ≤ x ≤ m, 1 ≤ y ≤ n.4.3 The Time Complexity of the AlgorithmSince, for each partial solution P x,y, we take the maximum value of the partial solutions P i,c, 1 ≤ i < x, the time complexity is O.5 Scheduling with the Job Separation Constraint5.1 The ProblemWe can now study the third and most general spatial constraint —the Job-separation constraint. An n × n matrix D represents this constraint: D p,q= 1(1 ≤ i ≤ n, 1 ≤ j≤ n), when job j p and j q cannot be done simultaneously. Otherwise, the elements of D are 0. Note that D is symmetric. We s eek a solution set R = {(p, q)|1 ≤ p ≤ m, 1 ≤ q ≤ n, W p,q> 0}, for which the following three conditions are satisfied:1. For all (p1, q1), (p2, q2) ∈ R, p1< p2 if and only if q1< q2(Non-crossing constraint)2. For all (p, q) ∈R, if 1 ≤ p’≤ m and p’= p, an d a ≤ q’≤ b, where a = max{1, q − s p} and b = max{q + s p, n}, then (p’, q’) ∈R (Neighborhood constraint)3. For all (p, q) ∈R, if 1≤p’≤ m, and D q,q’= 1, then (p’, q’)∈R(Job-separation constraint)The objective is to find a set R which maximizes total weigh t ∑(p,q)∈rWp,q where each job is assigned to at most one crane and each crane is assigned to at most one job.5.2 Proof of NP-completenessTo show that this problem is NP-complete, we use the Independent Set problem which is defined as follows: Given a gra ph G= (V, E) and a positive integer k≤ |V |, is there a V’⊆ V such that for all u, v ∈V’, the edge (u, v) is not in E and |V’| ≥ k?In order to prove that this problem is NP-hard, we transform an arbitrary instance of the Independent Set problem to the problem in polynomial time. Assuming there are n nodes in the graph G = (V, E) of the Independent Set problem, we construct the model with n cranes and n jobs where the only edges are (1, 1), (2, 2),..., (n, n), all with weight equal to 1. The Job-separation constraint matrix D is defined as follows: For all(x, y) ∈ E, D x,y= 1, otherwise D x,y= 0, 1 ≤ x, y ≤ n. The transformation is illustrated in Figure 5 and can be achieved in polynomial time.Now we show that the Independent Set problem has a solution of size k if and only if the problem has a solution with total profit k. First, if there are k independent nodes in graph G, there must be k jobs that do not, pairwise, conflict. Since we constructed n parallel edges with weight 1, the Non-crossing constraint and Neighborhood constraint do not have any effect here. Hence, we can use k cranes to do the k jobs without violating the Job-separation constraint with total profit k. If we now assume that there is a solution in this problem with profit k, there must be k jobs selected without violating the Job-separation constraint. There must be k nodes that are not connected by any edges and therefore a set of nodes of size k.We can verify solutions by checking crane-job assignments one by one for violation of the three constraints. Clearly, this can be done in polynomial time, so the problem is in the class NP. Since the problem has been shown to be NP-hard, it is NP-complete and, unless P = NP, there are no polynomial algorithms to solve it optimally. It would be useful therefore to develop heuristic solutions for the problem, which we do in the following sections.5.3 A Probabilistic Tabu Search ApproachTabu Search (TS) is a search procedure that iterates from one solution to another by moves in a neighborhood space with the help of an adaptive memory. Probabilistic Tabu Search (PTS) is a variant of TS, which places emphasis on randomization when compared with basic TS . The basic approach is to create move evaluations that include references to the tabu status and other relevant biases from TS strategies using penalties, modifying underlying decision criterion and selecting the next move among those neighborhood moves with different probabilities which are based on different evaluation values . In this section, we describe how it can be employed for the crane scheduling problem.5.3.1 Neighborhood StructureFrom an initial feasible solution obtained by a greedy method or a random crane-job assign－ment, the graph representation becomes almost edge ―saturated‖, i.e. we can hardly add an edge without violating the Non-crossing, Neighborhood and Job-separation constraints. We can however delete an edge from the current solution and try to add other edges until it is ―saturated‖ again. Deleting the edge which connects crane c and job j allows some cranes and jobs to become assignable. Obviously, thesecan only come from cranes and jobs which are neighbors to c and j, respectively, which do not violate the Non-crossing constraint w.r.t. all current assignments (discounting the c to j assignment). Jobs selected must also satisfy the Neighborhood and Job-separation constraints. After deleting the edge connecting c to j, we consider each neighbor of c from these feasible neighbors together with c, one by one. For each crane, we assign a probability p1for it to be selected for a job. For each selected crane, we have two types of assignments: one is a greedy assignment which selects a compatible job with the largest weight; the other is a random assignment which randomly picks one job from all the compatible jobs. Which scheme is chosen depends on yet another probability, p2.5.3.2 Tabu Search MemoryTS memory structures guide the search process. There are two kinds of memory structures. One is ―short-term memory‖, which can prevent the search from being trapped in a local optimum and the other is ―long-term memory‖, which provides diversification and inten－sification.Short-term memory restricts the composition of new solutions generated. If an edge is deleted in a move, we forbid its addition in the next few moves; similarly, if an edge is added in a move, we forbid its deletion in the next few moves. Such a mechanism prevents the search from revisiting local optima in the short term and reduces the chance of cycling in the long term.How long a restriction is in effect depends on a tabu tenure parameter, which identifies the number of iterations a particular restriction remains in force . We implemented short- term memory using a recency-based memory structure as follows.future iteration values that forbid a reversal of the moves on adding edge (x, y) or deleting edge (x, y). Furthermore, let tabu add tenure and tabu delete tenure be the values of tabu tenure for these two moves. When the TS restriction is imposed, we update the recency memory by:tabu add(x, y) = iter + tabu add tenuretabu delete(x, y) = iter + tabu delete tenureWe assign positive penalties to edges in tabu status, which means they are forbidden by the recency memory.A TS restriction is overridden by aspiration if the outcome of the move under consideration is sufficiently desirable. This can be achieved by deducting a large numberfrom the total penalty.5.3.3 Move EvaluationAfter finding all neighborhood candida te moves, we evaluate these moves so that they are ready for selection. The resulting evaluation value is in two parts: the total profit and the penalties. For our crane scheduling problem, the penalties comprise: (1) Short-term memory penalties which include tabu status penalties as well as aspiration satisfaction ―penalties‖ (2) Long-term memory penalties which include transition measure and residence measure penalties and (3) Penalties for other biases.5.3.4 Probabilistic Move SelectionAfter evaluating all candidate moves, we select one move to proceed. The fundamental idea of move selection is to choose the best move, i.e., choose the move with the highest evaluation. However, we found that this greedy selection strategy is strongly biased. We therefore made adjustments using probabilities. The strategy for a probabilistic move selection is given as follows:1. Generate the candidate list and evaluate candidate moves which have described above2. Select the move from the candidate list with the highest evaluation value3. Accept the move with probability p and exit; otherwise, go to (4). Here, p is a param-eter and is set to 0.3 in the algorithm4. Remove the move from the candidate list. If the list is empty, accept the first move ofthe original candidate list and exit. Otherwise, go to (2).It is easily shown that the probability of choosing one of the best k moves is 1 − (1 − p)k, which is large even if p is not large. For example, if p is 0.25, the probability of choosing the best 5 moves is 0.763, the best 10 moves is 0.944. We can therefore choose relatively high evaluation moves while avoiding favoring those with highest evaluations always.5.4 SWO with Local Search Approach―Squeaky Wheel‖ Optimization (SWO) is a general approach to optimization and consists of a Construct-Analyze-Prioritize cycle at its core. The Analyzer will assign a numerical ‖blame‖ value to the problem elements that c ontribute to shortcomings in the current solution. The Prioritizer will modify sequences of problem elements and。

To gain a certificate of competency for a cabin controlled bridge or gantry crane you must pass anassessment for a Bridge and gantry crane certificate conducted by an assessor registered by the WorkcoverAuthority.Before taking the assessment you must obtain a log book and learn the competencies required to pass theassessment. Applicants must be at least 18 years old to gain a certificate.It is illegal to operate a cabin controlled bridge or gantry crane without a Bridge and gantry cranecertificate or a log book (under the supervision of a certificated driver).A cabin controlled bridge or gantry crane driver must know:●how to safely operate a bridge or gantry crane●how to detect any mechanical faults●about slinging loads,sheaves and drums,rope terminations,anchors andattachmentsIt is the responsibility of the applicant to make sure that a bridge or gantry crane of the correct class isavailable for the assessment at their workplace or has permission to use a crane at another location.If you operate this type of crane and sling loads in connection with the operation of this type of crane youwill require a Dogging certificate in addition to being competent in its operation. See A guide for doggingavailable from the WorkCover Authority.桥梁合格证书起重机和龙门起重机为了获得一个龙门式起重机的合格证书，你必须通过操作龙门起重机进行评估，然后由劳保局注册管理局评估而得到的证书。

Portal crane structure and working principle Portal crane is a metal structure, the four major agencies and the three major components of the overall system. Figure 1-1 for the M10-25 portal crane, its metal structure: a boom system, Renzi Jia 4, Room 6, dial 7, 8, in turn, door-9, 10 ladder platform, cab 14. Four bodies have: Change bodies 2, operating 12 agencies, or organisations from 15, 16 and the rotary mechanism for the completion of cross pieces of action which the hydraulic system 3.Three systems: the power supply to the control panel 21, Resistance Box 22; manipulation used to manipulate the drivers seat 20; used for security and anti-overload limiter 5 to 19 devices. In addition, for ease of manipulation and grab 18 set grab stabilizer 17, and cable volumes SR ll, 13, and other support under. These components to work together to complete the lifting of goods and transport operations.1. Lifting bodies图：1—1In order to facilitate the transition to double-rope grab bulk cargo handling, general portal cranes from the double-reel or body, the two motors were driven by their respective reducer, a slowdown after three output and promote their respective volumes of wire rope SR. Or from one end of rope to a fixed volume in Brief, Renzi Jia on the other end through the pulley and compensation as the two ends of the bridge of the nose of the pulley, and then fixed on the hook or grab.2. Change agenciesThe portal crane Change often there are several forms of transmission, the transmission line as:(1) fan-shaped gear drive a motor reducer a Change Change gear ofa small fan-shaped gear of a tension bar, so that the main par Movement (Change);(2) Change screw and nut drive a motor reducer a Change Change Change screw a nut, so that the main par Movement (Change)图：1—2(3) gear, rack Change Change Change rack ofa small gear, the main leader movement (Change);(4) Change hydraulic transmission of a hydraulic pump motor fuel tank of a variation of a connecting rod. At the main Movement (Change).In order to improve the efficiency of cranes and better meet operational requirements, using a portal crane working Change body, the band set range. Change the characteristics of this work is the number of frequent, varying resistance larger and higher speed range. And then, if only a simple swing crane boom Change the way, it will cause the focus of Boom, by the admission of devices and mobile hanging in the level of the sport at the same time have a take-off and landing, in Figure 1-2. When the boom of a change in perspective α, by the hanging of a certain distance from Mobile, but also improve the hanging of a certain height h.This makes drive in the Change process, in addition to general must overcome the resistance, it is also necessary to overcome because of boom and hanging themselves lifting heavy objects caused by resistance, not only to increase power-driven, but also an increase of drivers operating location Difficulties. To this end, it was designed Boom lifting weights and balance system of compensation device. Boom balance system is the role of the boom system in the center of Change does not occur in the course of movements; lifting weights compensation device that is the role of weight in the process of variation along the track of moving closer to level.In the portal crane, the compensation devices are generally twomethods: the compensation law and the composition of the rope Boom Compensation Act.(1) the rope's Compensation ActIn lifting the rope pulley system to introduce compensation group, in Figure 1-3. - Oriented arm of a crane and pulley A rotation of the stent on the pulley B, composed of compensation-pulley blocks. When set up or arm, the arm-pulley A 0 A along with a radius of the arc for the movement to A ', at this time, rehabilitation pulley group the distance between the two pulley around. By choosing the appropriate size and pulley group rate, we can release to the pulley group of the rope, to compensate for the higher end of the crane, so that heavy objects along the approximate level of mobile line.(2) portfolio Boom Compensation Act① This is a special type of split-hinged combination to achieve compensation purposes, figure 1-4 is one of the form. 2 as the bridge of the nose with a hinged Boom, Lasheng 3 fixed to the trunk beam, the other end connected to the crane rotating platform on the framework. Change, as the bridge of the nose due to swing, Lasheng point of contact with their position that is changing, which is equivalent to the diagram of a quadrilateral hinged side in the event of a change. If appropriate choice quadrilateral side of the ratio, you can achieve when heavy objects can range along the approximate level of mobile line.At present, China's production of the portal cranes are even Qian compensation to the four institutions.图：1—3 图：1—4 图1—5② plans for the 1-5 combination Boom Compensation Act of another form, it is also unchanged from a number length of the rigid bar. The system is also a feature of the campaign plane with four Qian agencies. It is also the split-swing, as a bridge of the nose to the endpoint in a certain range of movement for close to the horizon, such reached weights in the range of movement when the purpose.3. Rotating bodiesFrom one or two rotating torque motor output of the worm reducer or gearreducer slowdown, driven rotary small gear, the gear to promote small fixed on the rotating column to the ring gear, so that the upper portal crane Rotation, to complete their tasks.4. Run institutionsBy two or four walking by their respective torque motor output slowdown after the reducer, transmission gear to open group, and then drive round the door Walking along the track of movement to achieve the door for the purpose of changing jobs. It can also be used for loading and unloading of cargoes walk. The portal crane lifting, rotating, varying the three institutions can work alone or joint operations, to complete the necessary work content.门座式起重机构造与工作原理门座式起重机是由金属结构、四大机构和三大系统组成的整体。

The History of Crane1.OverviewThe first construction cranes were invented by the Ancient Greeks and were powered by men or beasts of burden, such as donkeys. These cranes were used for the construction of tall buildings. Larger cranes were later developed, employing the use of human treadwheels, permitting the lifting of heavier weights. In the High Middle Ages, harbor cranes were introduced to load and unload ships and assist with their construction – some were built into stone towers for extra strength and stability. The earliest cranes were constructed from wood, but cast iron and steel took over with the coming of the Industrial Revolution.For many centuries, power was supplied by the physical exertion of men or animals, although hoists in watermills and windmills could be driven by the harnessed natural power. The first 'mechanical' power was provided by steam engines, the earliest steam crane being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century. Modern cranes usually use internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capability than was previously possible, although manual cranes are still utilized where the provision of power would be uneconomic.Cranes exist in an enormous variety of forms – each tailored to a specific use. Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. For a while, mini - cranes are also used for constructing high buildings, in order to facilitate constructions by reaching tight spaces. Finally, we can find larger floating cranes, generally used to build oil rigs and salvage sunken ships. This article also covers lifting machines that do not strictly fit the above definition of a crane, but are generally known as cranes, such as stacker cranes and loader cranes.2. History（1）Ancient GreeceThe crane for lifting heavy loads was invented by the Ancient Greeks in the late 6th century BC. The archaeological record shows that no later than c.515 BC distinctive cuttings for both lifting tongs and lewis irons begin to appear on stone blocks of Greek temples. Since these holes point at the use of a lifting device, and since they are to be found either above the center of gravity of the block, or in pairs equidistant from a point over the center of gravity, they are regarded by archaeologists as the positive evidence required for the existence of the crane.The introduction of the winch and pulley hoist soon lead to a widespread replacement of ramps as the main means of vertical motion. For the next two hundred years, Greek building sites witnessed a sharp drop in the weights handled, as the new lifting technique made the use of several smaller stones more practical than of fewer larger ones. In contrast to the archaic period with its tendency to ever-increasing block sizes, Greek temples of the classical age like the Parthenon invariably featured stone blocks weighing less than 15-20 tons. Also, the practice of erecting large monolithic columns was practically abandoned in favor of using several column drums.Although the exact circumstances of the shift from the ramp to the crane technology remain unclear, it has been argued that the volatile social and political conditions of Greece were moresuitable to the employment of small, professional construction teams than of large bodies of unskilled labor, making the crane more preferable to the Greek polis than the more labor-intensive ramp which had been the norm in the autocratic societies of Egypt or Assyria.The first unequivocal literary evidence for the existence of the compound pulley system appears in the Mechanical Problems (Mech. 18, 853a32-853b13) attributed to Aristotle (384-322 BC), but perhaps composed at a slightly later date. Around the same time, block sizes at Greek temples began to match their archaic predecessors again, indicating that the more sophisticated compound pulley must have found its way to Greek construction sites by then.Ancient RomeThe heyday of the crane in ancient times came during the Roman Empire, when construction activity soared and buildings reached enormous dimensions. The Romans adopted the Greek crane and developed it further. We are relatively well informed about their lifting techniques, thanks to rather lengthy accounts by the engineers Vitruvius (De Architectura 10.2, 1-10) and Heron of Alexandria (Mechanica 3.2-5). There are also two surviving reliefs of Roman treadwheel cranes, with the Haterii tombstone from the late first century AD being particularly detailed.The simplest Roman crane, the Trispastos, consisted of a single-beam jib, a winch, a rope, and a block containing three pulleys. Having thus a mechanical advantage of 3:1, it has been calculated that a single man working the winch could raise 150 kg (3 pulleys x 50 kg = 150), assuming that 50 kg represent the maximum effort a man can exert over a longer time period. Heavier crane types featured five pulleys (Pentaspastos) or, in case of the largest one, a set of three by five pulleys (Polyspastos) and came with two, three or four masts, depending on the maximum load. The Polyspastos, when worked by four men at both sides of the winch, could already lift 3000 kg (3 ropes x 5 pulleys x 4 men x 50 kg = 3000 kg). In case the winch was replaced by a treadwheel, the maximum load even doubled to 6000 kg at only half the crew, since the treadwheel possesses a much bigger mechanical advantage due to its larger diameter. This meant that, in comparison to the construction of the Egyptian Pyramids, where about 50 men were needed to move a 2.5 ton stone block up the ramp (50 kg per person), the lifting capability of the Roman Polyspastos proved to be 60 times higher (3000 kg per person).However, numerous extant Roman buildings which feature much heavier stone blocks than those handled by the Polyspastos indicate that the overall lifting capability of the Romans went far beyond that of any single crane. At the temple of Jupiter at Baalbek, for instance, the architrave blocks weigh up to 60 tons each, and one corner cornice block even over 100 tons, all of them raised to a height of about 19 m. In Rome, the capital block of Trajan's Column weighs 53.3 tons, which had to be lifted to a height of about 34 m (see construction of Trajan's Column).It is assumed that Roman engineers lifted these extraordinary weights by two measures (see picture below for comparable Renaissance technique): First, as suggested by Heron, a lifting tower was set up, whose four masts were arranged in the shape of a quadrangle with parallel sides, not unlike a siege tower, but with the column in the middle of the structure (Mechanica 3.5). Second, a multitude of capstans were placed on the ground around the tower, for, although having a lower leverage ratio than treadwheels, capstans could be set up in higher numbers and run by more men (and, moreover, by draught animals). This use of multiple capstans is also described by AmmianusMarcellinus (17.4.15) in connection with the lifting of the Lateranense obelisk in the Circus Maximus (ca. 357 AD). The maximum lifting capability of a single capstan can be established by the number of lewis iron holes bored into the monolith. In case of the Baalbek architrave blocks, which weigh between 55 and 60 tons, eight extant holes suggest an allowance of 7.5 ton per lewis iron, that is per capstan. Lifting such heavy weights in a concerted action required a great amount of coordination between the work groups applying the force to the capstans.Middle AgesDuring the High Middle Ages, the treadwheel crane was reintroduced on a large scale after the technology had fallen into disuse in western Europe with the demise of the Western Roman Empire. The earliest reference to a treadwheel (magna rota) reappears in archival literature in France about 1225, followed by an illuminated depiction in a manuscript of probably also French origin dating to 1240. In navigation, the earliest uses of harbor cranes are documented for Utrecht in 1244, Antwerp in 1263, Brugge in 1288 and Hamburg in 1291, while in England the treadwheel is not recorded before 1331.Generally, vertical transport could be done more safely and inexpensively by cranes than by customary methods. Typical areas of application were harbors, mines, and, in particular, building sites where the treadwheel crane played a pivotal role in the construction of the lofty Gothic cathedrals. Nevertheless, both archival and pictorial sources of the time suggest that newly introduced machines like treadwheels or wheelbarrows did not completely replace more labor-intensive methods like ladders, hods and handbarrows. Rather, old and new machinery continued to coexist on medieval construction sites and harbors.Apart from treadwheels, medieval depictions also show cranes to be powered manually by windlasses with radiating spokes, cranks and by the 15th century also by windlasses shaped like a ship's wheel. To smooth out irregularities of impulse and get over 'dead-spots' in the lifting process flywheels are known to be in use as early as 1123.The exact process by which the treadwheel crane was reintroduced is not recorded, although its return to construction sites has undoubtedly to be viewed in close connection with the simultaneous rise of Gothic architecture. The reappearance of the treadwheel crane may have resulted from a technological development of the windlass from which the treadwheel structurally and mechanically evolved. Alternatively, the medieval treadwheel may represent a deliberate reinvention of its Roman counterpart drawn from Vitruvius' De architectura which was available in many monastic libraries. Its reintroduction may have been inspired, as well, by the observation of the labor-saving qualities of the waterwheel with which early treadwheels shared many structural similarities.Structure and placementThe medieval treadwheel was a large wooden wheel turning around a central shaft with a treadway wide enough for two workers walking side by side. While the earlier 'compass-arm' wheel had spokes directly driven into the central shaft, the more advanced 'clasp-arm' type featured arms arranged as chords to the wheel rim, giving the possibility of using a thinner shaft and providing thus a greater mechanical advantage.Contrary to a popularly held belief, cranes on medieval building sites were neither placed on the extremely lightweight scaffolding used at the time nor on the thin walls of the Gothic churches which were incapable of supporting the weight of both hoisting machine and load. Rather, cranes were placed in the initial stages of construction on the ground, often within the building. When a new floor was completed, and massive tie beams of the roof connected the walls, the crane was dismantled and reassembled on the roof beams from where it was moved from bay to bay during construction of the vaults. Thus, the crane ‘grew’ and ‘wandered’ with the building with the result that today all extant construction cranes in England are found in church towers above the vaulting and below the roof, where they remained after building construction for bringing material for repairs aloft.Less frequently, medieval illuminations also show cranes mounted on the outside of walls with the stand of the machine secured to putlogs.Mechanics and operationIn contrast to modern cranes, medieval cranes and hoists - much like their counterparts in Greece and Rome - were primarily capable of a vertical lift, and not used to move loads for a considerable distance horizontally as well. Accordingly, lifting work was organized at the workplace in a different way than today. In building construction, for example, it is assumed that the crane lifted the stone blocks either from the bottom directly into place, or from a place opposite the centre of the wall from where it could deliver the blocks for two teams working at each end of the wall. Additionally, the crane master who usually gave orders at the treadwheel workers from outside the crane was able to manipulate the movement laterally by a small rope attached to the load. Slewing cranes which allowed a rotation of the load and were thus particularly suited for dockside work appeared as early as 1340. While ashlar blocks were directly lifted by sling, lewis or devil's clamp (German Teufelskralle), other objects were placed before in containers like pallets, baskets, wooden boxes or barrels.It is noteworthy that medieval cranes rarely featured ratchets or brakes to forestall the load from running backward. This curious absence is explained by the high friction force exercised by medieval treadwheels which normally prevented the wheel from accelerating beyond control. Harbor usageAccording to the "present state of knowledge" unknown in antiquity, stationary harbor cranes are considered a new development of the Middle Ages. The typical harbor crane was a pivoting structure equipped with double treadwheels. These cranes were placed docksides for the loading and unloading of cargo where they replaced or complemented older lifting methods like see-saws, winches and yards.Two different types of harbor cranes can be identified with a varying geographical distribution: While gantry cranes which pivoted on a central vertical axle were commonly found at the Flemish and Dutch coastside, German sea and inland harbors typically featured tower cranes where the windlass and treadwheels were situated in a solid tower with only jib arm and roof rotating. Interestingly, dockside cranes were not adopted in the Mediterranean region and the highly developed Italian ports where authorities continued to rely on the more labor-intensive method ofunloading goods by ramps beyond the Middle Ages.Unlike construction cranes where the work speed was determined by the relatively slow progress of the masons, harbor cranes usually featured double treadwheels to speed up loading. The two treadwheels whose diameter is estimated to be 4 m or larger were attached to each side of the axle and rotated together. Today, according to one survey, fifteen treadwheel harbor cranes from pre-industrial times are still extant throughout Europe.[28] Beside these stationary cranes, floating cranes which could be flexibly deployed in the whole port basin came into use by the 14th century.RenaissanceA lifting tower similar to that of the ancient Romans was used to great effect by the Renaissance architect Domenico Fontana in 1586 to relocate the 361 t heavy Vatican obelisk in Rome. From his report, it becomes obvious that the coordination of the lift between the various pulling teams required a considerable amount of concentration and discipline, since, if the force was not applied evenly, the excessive stress on the ropes would make them rupture.Early modern ageCranes were used domestically in the 17th and 18th century. The chimney or fireplace crane was used to swing pots and kettles over the fire and the height was adjusted by a trammel.4. Types of the cranesMobileMain article: Mobile craneThe most basic type of mobile crane consists of a truss or telescopic boom mounted on a mobile platform - be it on road, rail or water.FixedExchanging mobility for the ability to carry greater loads and reach greater heights due to increased stability, these types of cranes are characterized that they, or at least their main structure does not move during the period of use. However, many can still be assembled and disassembled.外文翻译起重机的历史1. 概况第一台具有机械结构的起重机是由古希腊人发明的，并且由人或者是牲畜比如驴，作为动力源。