UNIT ONE：
The automobile speech sound system of the computer control
1.Forewords
In the last few years, the highway traffic caused development of our country very rapidly, has raised the vehicle traversal speed and circulation density greatly ,especially the appearance of highway has followed to come to traffic accident ,and also occurred again and again, at the same time ,caused personal casualties and economic property loss. How to reduce traffic accident have become urgent matters. Driver of carefullessness is the one of important reason that traffic accident occurs , therefore developing a set of simple reliable, can each partial conditions of automatic detection vehicle, discover unusual condition the safe system that can send the hint of speech sound in time to driver have great actual meaning.
Driver of carefullessness is the one of important reason that traffic accident occurs , therefore develop a set of simple reliable, can each partial conditions of automatic detection vehicle, discover unusual condition the safe system that can send the hint of speech sound in time to driver have great actual meaning.
2.Systems design ideological
basised to initiate the common factor of accident, this set of system will realize following detection function:
ａ. closing door , detecting whether the gate lock has beenn deducted;
ｂ. detecting the cooling water of engine warm up;
ｃ. detecting the oil quantity of engine machine;
ｄ. detecting the braking oil quantity;
ｅ. when automobile backs a car , detecting the barrier condition after the automobile;
ｆ. the wear out condition of detection automobile brake friction flat;
ｇ. Detecting the condition of road surface;
ｈ. Detecting whether driver is excessive drinking.
After automobile engine starts , system begins detecting, when discovering unusual condition, such as door do not close , the warm error of cooling water is the hint of speech sound high , oil quantity is below and backing a car ,the barrier is near next to the automobile , friction flat excessively wear and the coefficient of friction of road surface .the alcohol content in the little air of driver's cab error higher and so on, starting system send the hint of speech sound.
In the system of speech sound adopting the Ｔ6668 chip record systems of speech synthesis and the regenerative signal of speech sound. According to needs ,in the control of ＣＰＵ, ask to be able to export the following hint speech sounds:
ａ. noticing door do not close;
ｂ. Noticing the temperature exceed;
ｃ. the oil quantity of machine oil is below;
ｄ. brake oil quantity is below;
ｅ. care left rear obstacle;
ｆ. care right rear obstacle;
ｇ. Braking ineffectiveness is danger;
ｈ. noticing the road surface than slippery;
ｊ. wine rear driving danger.
In the entire design, being economy , simple, reliable to popularize.
3.Systematic hardwares
To complete the above-mentioned every detection and the export requirement of speech sound, this system adopts the hardware structure that shows as Fig.1.
图1 硬件结构图
Electronic controlling machine adopts the 8031 single chip machine and the corresponding digital circuit, by it, gather the signal of each sensor , decide and control the synthetic output of speech sound as a result according to handling and calculation. Because of the 8031 single chip machine without ＲＯＭ, expand a slice of ＥＰＲＯＭ2764 is as the program memory.
The system of speech sound with Japanese Dong Zhi company's production Ｔ6668 chips of speech synthesis is core, additionally adopting again a slice of ＥＰＲＯＭ27,256 stock record the data of speech sound of good system in advance, managing the data in which is using 8031 , according to the various faults to take the adjust, make up , from the Ｔ6668 output. In this design the Ｔ6668 adopts the ＣＰＵoperating pattern and the 8031 connections ,which instruction is written in by the Ｔ6668 ＣＰＵinterface. The Ｔ6668 ＣＡＳ1 end and data input end 、ＤＩend difference and 74 ＬＳ165 ( 8 and/string shift register ) ＣＫend 、ＱＨend are linked , so ＣＰＵwith only ＥＰＲＯＭof the data of 27,256 by the data bus line send into 74 ＬＳ165 the output of speech sound that gets composition.
In this design, it is for door , backing a car detection adopted the ＯＲＤ226 dry spring flat switch sensors. The spring flat switch sensor is a kind of magnetic drive type switch, which sport partial qualities are little ,and rapid that natural frequency respond speed high and service life grows , even if in the place in which automobile and trolleybus often have vibration , using fully , especially be used in being the sensor with the monitor of relevant automobile extensively part.
For the engine machine oil the detection of oil quantity and braking oil quantity adopt ＣＥ4-1 - 5 type floats - spring flat liquid position sensor.
Measuring the temperature of cooling fluid to use thermistor type liquid use temperature sensor.
With the negative thermistor NTC of temperature coefficient, its temperature value and simulated voltage signal become inverse ratio. Imitate voltage signal to go through condenser strain the INO simulated signal passageway that sent into ADC0 809 after wave.
When engine preheats , engine water is warm to be 70 to take to show degree, in the data memory in single flat machine, stocking data is compared , after contrast report to alarm the circuit silent light report to the police. Along with the work of unceasing engine, the water warm beginning of engine goes up gradually, when water is warm to exceed 95 to take to show degree only flat microcomputer drive report to alarm circuit report to alarm. Reminding the cooling system of driver notice engine the
change of temperature.
The weared out condition of the detection automobile braking friction flat uses the wear detection sensor. When installing maked friction flat sensor Ｕthe top of word shape the wear limit location that locates in brake brake pad on, when friction flat wear goes to assigned limit Ｕword shape part have been ground to break, circuit break open. At the same time, this unusual signal will be sent into the single flat microcomputer.
For the detection driver, whether drink choose the
semiconductor gas sensor that applies to ethanol gas
detection , when the alcohol content in the air of
driver's cab reaches certain density, sends a alarm
signal to the single chip microcomputer.
When automobile back a car , system uses the
barrier of supersonic detection vehicle rear. The rear
bumper two ends of automobile pack to set up
supersonic project/receiver, two project/receiver
with the way of equal time, project/in proper order
to take over supersonic , is circulating to go on
again and again. Because of this cycle time is from
ＣＰＵcontrol, therefore this system will not get the
wrong signal influence from external sound wave.
Automobile distance the distance of barrier is pass
through sonar send reflection return the time that this
route spends come to survey and calculate , calculation
has following type.
ｄ=1/2*ct
ｃ=331+0.6θ
In type ｄ——— automobile far from the
distance of barrier
ｃ——— supersonic the speed that
propagated in air
ｔ——— the time of mensuration
θ ——— vehicle outside air
temperature
Angle sonar the barrier that can be measured
approximate in 50ｃｍscope within, pawn barrier
distance automobile do not go to 50ｃｍ, send
speech sound to report to alarm.
On the road surface that the moist of rainy day or
ice snow covers , between road surface and wheel tyre, coefficient of friction is little , vehicle is all right with high speed or sudden braking makes automobile overturn easily, which knows vehicle course Central Africa, is frequently dangerous. Therefore in this system spoil frequently some point using driver in the course of traveling to move brake movement, detection tyre and the slip rate of road surface ( racial of drive wheel and the bad speed of rotational speed of undrive wheel of drive wheel), and the accordingly estimation condition of road surface. And beg the specific practice of slip rate is the sensor of rotational speed of edd current installation in drive with undrive wheel on, measure the difference of rotational speed , so making slip rate finally in order to remind that driver
reduces speed.
4.Systematic softwares
The main program block diagram shows as Fig.2. The subprogram
of speech sound shows as Fig.3.
After system starts eclectricity , main program first complete
initialization work includes setting up storehouse indicator , sets initial
value and the working way of timer/counter, put relevant storage
element initial value, start timer/counter open suspend and so on. Then
shiping inquire each state input line, looking over whether needs report
to alarm. For instance, when sensor detection going to automobile is
backing a car,ＣＰＵchoose want trigger project address, then,
starting to project circuit and begin to reckon by time , in the given time
if taking over signal from postpone time can calculate barrier arrive to
project a little distance. If taking over signal in the given time do not
think that barrier far from projects a little distance have exceeded the
distance taken over, then project/again to take over next project a little signal. According to the signal taking over and calculating the result, after judging vehicle left or right whether have barrier.
In design using the timer of 8031 Ｔ0 reckon by time , in week 0.5ｓ, with the counter of 8031 Ｔthe pulse that 1 sends for the wheel sensor of rotational speed count. Setting timer Ｔ0 is 250μｓ, therefore in timer Ｔ0 spill over to suspend service program in, basis whether spill over 2000 times come to judge whether arrival 0.5ｓ, at the same time for the calculation of wheel rotational speed and slip rate, is also completed in suspend service program.
When reporting to alarm, the subprogram of speech sound used ( Fig.3 ) are the important link of regenerative speech sound, major function is will control order write in Ｔ6668 come to realize speech sound revive.
5.Summarize
Using various sensors, this system can detect various dangerous condition and send the speech sound in time report to alarm , being against contracting in unran, avoiding to occurs the accident and becomes the good assistant of driver safely trip vehicle. This technology is willing to seek investor and cooperative partner.
UNIT TWO：
The 8051-single chip microcomputer
8051 is the representative product in the MCS-51 series single flat mictocomputer, it has integrated inside the center with the powerful function processor, and have contained hardware to multiply the 8 parallel mouthes of divider, the 21 control registers for special purpose, the program memory of 4 kB, the data memory of 128 bytes and 4 groups , two 16 but editing processor as well as the serial mouth of programming timer / counter and a whole duplex operation.
MCS-51 have comparison big seek address space, address line width reaches the piece of 16, external data memory and program memory seek the address scope reaching to 216 = 64 kB, which
has been larger as only the flat microcomputer control, at the same time which have for the mouth of I/O visit ability. Besides, MCS-51 adopts modular structure, but a convenient emendation modular can draw the compatible new product of foot and instruction. So, make product form seriation easily.
The working frequency of MCS-51 single flat microcomputer is 2-12 MHz, when vibration frequency is 12 MHz, a machine period is 1 us, the speed should be said that it is more rapid.
8051 in integrated perfect various suspend source, user can very much control and use its function conveniently , makers that it's application scope increase , can say that it can satisfy the most of application occasions absolutely.
MCS-51 that is the major parts of personal computer integrated in a heart flat on, make data deliver distance shorten greatly, reliability is higher , traversal speed more piece. Since belonging to chip the personal computer that melts , each function parts structure and the layout in chip reach optimization, the ability of interference rejection strengthens , working is also stabilized relatively. Therefore in industry measure the controlling system, using the only flat microcomputer is the most ideal option. The single flat microcomputer belongs to the typical embedded system, so it is low end control systematic best device.
8051 is the typical product of MCS-51 series single flat mictocomputer, we go on with the type of this representative, which is systematic to explain.
8051 single slices microcomputer contains the central processing unit and program memory ( ROM ) , data memory ( RAM ) , timer / counter, parallel inputs or outputs(I/O) and serial interface with suspend few big units such as system and the 3 big bus lines such as data bus line, address bus line and control bus line.Now, we differentiate explanation:
1、Central processing unit:
Central processing unit( CPU ) is the key parts of the entire single flat microcomputer, which is the processor of 8 data widthes , can handle the 8 data or code of binary system, the complete operation and control input export function etc. And working CPU takes the responsibility for controling, commanding and managing entire unit system to coordinate operating.
2、Random access memory ( RAM):
8051 insides the 128 bytes of 8 user data storage elements and the 128 register units for special purpose, which is unified editing addtess, using privately register can only instruct datas used in stocking control, user can only visit , and can not be used to keep the user’s data, so user can RAM of using the only 128, can keep the intermediate result of reading the operation and data that written or the word type table of user definition.
3、Read only memory ( ROM ):
8051 possess 4096 of 8 covered membrane ROM, used in stocking user program original data or form.
4、Timer / counter ( ROM ):
8051 has the two-16 and programming timer / counter,which realization is timing or counting to produce suspend used in control program change direction.
5、Parallel inputs or outputs( I/O)：
8051 possess the 4 groups of 8 doors of I/O ( P0, P1, P2 or P3 ), which is used in the transmission for external data.
6、The serial mouth of duplex operation
The 8051 built in serial the communication mouthes of duplex operation, deliver used in the serial data between other equipment. This serial mouth can use to make asynchronous communication dispatcher ware, and also pawn at the same time shift ware use.
7、Suspend system:
8051 has more than perfect suspend function, and has two Outside suspend, two timing / counters suspend and one serial suspend , the prior rank that can satisfy different control requirement and has 2 levels is selected.
8、Clock circuit
The clock circuit with the 8051 built-in highest frequencies reaches to 12 MHz, which is used in the pulse sequential that produces entire only flat microcomputer operation . But 8051 single slices microcomputer needs the vibration capacity to put outside.
译文
第一篇：
计算机控制汽车安全语音提示系统
1、引言
近几年来,我国公路交通事业发展很快,尤其是高速公路的出现,大大提高了车辆运行速度及流
通密度,但随之而来的交通事故也频频发生,造成人员伤亡及经济财产损失。如何减少交通事故的发生已成为当务之急。驾驶员的疏忽大意是交通事故发生的重要原因之一,因此研制一套简单可靠,能自动检测车辆各部分状况,发现异常情况能及时向驾驶员发出语音提示的安全系统就有很大实际意义。
2、系统设计思想
根据引发事故的常见因素,这套系统将实现下列检测功能:
ａ关车门时,检测门锁是否扣紧;
ｂ检测发动机的冷却水温;
ｃ检测发动机机油油量;
ｄ检测制动油油量;
ｅ汽车倒车时,检测车后障碍物情况;
ｆ检测汽车制动器摩擦片的磨损情况;
ｇ检测路面状况;
ｈ检测驾驶员是否酗酒。
汽车发动机起动后系统开始检测,当发现异常情况时,如车门未关紧、冷却水温过高、油量不足、倒车时车后障碍物过近、摩擦片过度磨损、路面摩擦系数过小、驾驶室的空气中酒精含量过高等,
便启动安全语音提示系统发出语音提示。
在语音系统中采用Ｔ6668语音合成芯片录制并再生语音信号。根据需要,在ＣＰＵ的控制下,要求能输出以下的提示语音:
ａ注意车门未关;
ｂ注意温度超限;
ｃ机油油量不足;
ｄ制动油量不足;
ｅ小心左后障碍;
ｆ小心右后障碍;
ｇ制动失灵危险;
ｈ注意路面较滑;
ｊ酒后驾驶危险。
在整个设计中,要求经济、简单、可靠,便于推广。
3、系统硬件
为完成上述的各项检测及语音输出要求,本系统采用如图1所示的硬件结构。
电子控制器采用8031单片机和相应的数字电路,由它采集各传感器的信号,根据处理、计算结果决定并控制语音的合成输出。由于8031不含ＲＯＭ,因此扩展一片ＥＰＲＯＭ2764作为程序存储器。
语音系统以日本东芝公司生产的Ｔ6668语音合成芯片为核心,另外再采用一片ＥＰＲＯＭ27256存储事先录制好的语音数据,利用8031管理其中的数据,根据各种故障进行调取、组合,由Ｔ6668输出。在本设计中Ｔ6668采用ＣＰＵ操作模式与8031连接,其指令通过Ｔ6668的ＣＰＵ接口写入。Ｔ6668的ＣＡＳ1端和数据输入端ＤＩ端分别与74ＬＳ165(8位并/串移位寄存器)的ＣＫ端和ＱＨ端相连,这样,ＣＰＵ只要将ＥＰＲＯＭ27256的数据经数据总线送入74ＬＳ165便得到合成的语音输出。
在本设计中对车门、倒车检测均采用ＯＲＤ226干簧片开关传感器。干簧片开关传感器是一种磁驱动型开关,其运动部分质量小,固有频率高,响应速度很快,而且使用寿命长,即使是在汽车、电车等经常有振动的场所都可以充分使用,特别是可广泛用于与汽车有关的监控器的传感器部分。
对发动机机油油量和制动油油量的检测均采用ＣＥ4-1-5型浮子-簧片液位传感器。
测量冷却液温度使用热敏电阻式液用温度传感器。
检测汽车制动器摩擦片的磨损情况使用磨损检测传感器。在安装时,使摩擦片传感器Ｕ字形的顶端位于制动器摩擦块的磨损限度位置上,当摩擦片磨损到规定限度时,Ｕ字形部分被磨断,电路断开,同时这一异常信号将被送到单片机中。
为了检测驾驶员是否饮酒,选用适用于乙醇气体检测的半导体气敏元件,当驾驶室空气中的酒精含量达到一定浓度时,向单片机发出报警信号。
在汽车倒车时,系统利用超声波检测车辆后方的障碍物。在汽车的后保险杠两端装设超声波发射/接收器,两个发射/接收器以均等时间的方式,依次发射/接收超声波,循环反复进行。由于这一循环时间是由ＣＰＵ控制,因此该系统不会受到来自外部声波的错误信号影响。汽车距障碍物的距离是通过声纳发出到反射回来这段行程所花费的时间来测定并进行计算的,计算式如下: ｄ=12ｃｔｃ=331+0 6θ
式中ｄ———汽车距障碍物的距离
ｃ———超声波在空气中传播的速度
ｔ———测定的时间
θ———车外空气温度角
声纳可测得的障碍物大约在50ｃｍ范围以内,当障碍物距汽车不到50ｃｍ时,发出语音报警。
在雨天潮湿或冰雪覆盖的路面上,路面和车轮轮胎之间摩擦系数小,高速行车或突然制动容易使汽车颠覆,这在行车过程中非常危险。因此在该系统中,利用驾驶员在行驶过程中惯常有的点动制动动作,检测轮胎与路面滑移率(驱动轮和非驱动轮的转速差与驱动轮速度之比),并据此估算路面的状
况。而求滑移率的具体做法是将转速涡流传感器安装在驱动与非驱动轮上,测出转速差,从而算出滑移率,以提醒驾驶员降低车速。
4、系统软件
主程序框图如图2所示。语音子程序如图3所示。
系统通电后,主程序先完成初始化工作,包括设堆栈指针,设定定时器/计数器的工作方式及初值,将有关存储单元置初值,启动定时器/计数器,开中断等等。然后轮询各状态输入口线,查看是否需要报警。例如,当传感器检测到汽车正在倒车时,ＣＰＵ选定要触发的发射点地址,然后启动发射电路并开始计时,在给定时间内如接收到信号则由延迟时间可以计算出障碍物到发射点的距离。如在给定时间内接收不到信号,则认为障碍物距发射点的距离已超过可接收距离,然后再发射/接收下一个发射
点的信号。根据信号接收和计算的结果,可以判断车辆后左方和后右方是否有障碍物。
在设计中利用8031的定时器Ｔ0计时,周期为0 5ｓ,采用8031的计数器Ｔ1对车轮转速传感器发
出的脉冲计数。设定定时器Ｔ0为250μｓ,因此,在定时器Ｔ0的溢出中断服务程序中,根据是否溢出2000次来判断是否到达0 5ｓ,同时对车轮转速和滑移率的计算也在该中断服务程序中完成。
报警时调用的语音子程序(图3)是语音再生的重要环节,主要功能是将控制命令写入Ｔ6668来实现语音的再生。
5、总结
利用各种传感器,该系统可以检测出多种危险情况并及时发出语音报警,防患于未然,避免事故
的发生,成为驾驶员安全行车的好帮手。本技术愿寻求投资者和合作伙伴。
第二篇：
MCS-51单片机特性和结构
8051是MCS-51系列单片机中的代表产品，它内部集成了功能强大的中央处理器，包含了硬件乘除法器、21个专用控制寄存器、4kB的程序存储器、128字节的数据存储器、4组8位的并行口、两个16位的可编程定时/计数器、一个全双工的串行口以及布尔处理器。
MCS-51具有比较大的寻址空间，地址线宽达16条，即外部数据存储器和程序存储器的寻址范围达216=64kB，这作为单片机控制来说已是比较大的，这同时具备对I/O口的访问能力。此外，MCS-51采用模块化结构，可方便地增删一个模块就可引脚和指令兼容的新产品。从而容易使产品形成系列化。
MCS-51单片机的工作频率为2-12MHz，当振荡频率为12MHz时，一个机器周期为1us,这个速度应该说是比较快的。
8051中集成了完善的各种中断源，用户可十分方便地控制和使用其功能，使得它的应用范围加大，可以说它可以满足绝大部分的应用场合。
MCS-51把微型计算机的主要部件都集成在一块心片上，使得数据传送距离大大缩短，可靠性更高，运行速度更块。由于属于芯片化的微型计算机，各功能部件在芯片中的布局和结构达最优化，抗干扰能力加强，工作亦相对稳定。因此，在工业测控系统中，使用单片机是最理想的选择。单片机属于典型的嵌入式系统，所以它是低端控制系统最佳器件。
8051是MCS-51系列单片机的典型产品，我们以这一代表性的机型进行系统的讲解。
8051单片机包含中央处理器、程序存储器(ROM)、数据存储器(RAM)、定时/计数器、并行接口、串行接口和中断系统等几大单元及数据总线、地址总线和控制总线等三大总线，现在我们分别加以说明：
1、中央处理器：
中央处理器(CPU)是整个单片机的核心部件，是8位数据宽度的处理器，能处理8位二进制数据或代码，CPU负责控制、指挥和调度整个单元系统协调的工作，完成运算和控制输入输出功能等操作。
2、数据存储器(RAM)：
8051内部有128个8位用户数据存储单元和128个专用寄存器单元，它们是统一编址的，专用寄存器只能用于存放控制指令数据，用户只能访问，而不能用于存放用户数据，所以，用户能使用的的RAM只有128个，可存放读写的数据，运算的中间结果或用户定义的字型表。
3、程序存储器(ROM)：
8051共有4096个8位掩膜ROM，用于存放用户程序，原始数据或表格
4、定时/计数器(ROM)：
8051有两个16位的可编程定时/计数器，以实现定时或计数产生中断用于控制程序转向。
5、并行输入输出(I/O)口：
8051共有4组8位I/O口(P0、P1、P2或P3)，用于对外部数据的传输。
6、全双工串行口：
8051内置一个全双工串行通信口，用于与其它设备间的串行数据传送，该串行口既可以用作异步通信收发器，也可以当同步移位器使用。
7、中断系统：
8051具备较完善的中断功能，有两个外中断、两个定时/计数器中断和一个串行中断，可满足不同的控制要求，并具有2级的优先级别选择。
8、时钟电路：
8051内置最高频率达12MHz的时钟电路，用于产生整个单片机运行的脉冲时序，但8051单片机需外置振荡电容。
前言 在目前激烈的市场竞争中，产品投入市场的迟早往往是成败的关键。模具是高质量、高效率的产品生产工具，模具开发周期占整个产品开发周期的主要部分。因此客户对模具开发周期要求越来越短，不少客户把模具的交货期放在第一位置，然后才是质量和价格。因此，如何在保证质量、控制成本的前提下加工模具是值得认真考虑的问题。模具加工工艺是一项先进的制造工艺，已成为重要发展方向，在航空航天、汽车、机械等各行业得到越来越广泛的应用。模具加工技术，可以提高制造业的综合效益和竞争力。研究和建立模具工艺数据库，为生产企业提供迫切需要的高速切削加工数据，对推广高速切削加工技术具有非常重要的意义。本文的主要目标就是构建一个冲压模具工艺过程，将模具制造企业在实际生产中结合刀具、工件、机床与企业自身的实际情况积累得高速切削加工实例、工艺参数和经验等数据有选择地存储到高速切削数据库中，不但可以节省大量的人力、物力、财力，而且可以指导高速加工生产实践，达到提高加工效率，降低刀具费用，获得更高的经济效益。 1.冲压的概念、特点及应用 冲压是利用安装在冲压设备（主要是压力机）上的模具对材料施加压力，使其产生分离或塑性变形，从而获得所需零件（俗称冲压或冲压件）的一种压力加工方法。冲压通常是在常温下对材料进行冷变形加工，且主要采用板料来加工成所需零件，所以也叫冷冲压或板料冲压。冲压是材料压力加工或塑性加工的主要方法之一，隶属于材料成型工程术。 冲压所使用的模具称为冲压模具，简称冲模。冲模是将材料（金属或非金属）批量加工成所需冲件的专用工具。冲模在冲压中至关重要，没有符合要求的冲模，批量冲压生产就难以进行；没有先进的冲模，先进的冲压工艺就无法实现。冲压工艺与模具、冲压设备和冲压材料构成冲压加工的三要素，只有它们相互结合才能得出冲压件。 与机械加工及塑性加工的其它方法相比，冲压加工无论在技术方面还是经济方面都具有许多独特的优点，主要表现如下； (1) 冲压加工的生产效率高，且操作方便，易于实现机械化与自动化。这是
附录A 英文文献 Drive axle/differential All vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road. Powerflow The drive axle must transmit power through a 90°angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels. This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels. Fig 1 Drive axle
控制系统基础论文中英文资料外文翻译文献 文献翻译 原文： Numerical Control One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC).Prior to the advent of NC, all machine tools were manual operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator . Numerical control represents the first major step away from human control of machine tools. Numerical control means the control of machine tools and other manufacturing systems though the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool, For a machine tool to be numerically controlled , it must be interfaced with a device for accepting and decoding the p2ogrammed instructions, known as a reader. Numerical control was developed to overcome the limitation of human operator , and it has done so . Numerical control machines are more accurate than manually operated machines , they can produce parts more uniformly , they are faster, and the long-run tooling costs are lower . The development of NC led to the development of several other innovations in manufacturing technology: 1.Electrical discharge machining. https://www.doczj.com/doc/a74567329.html,ser cutting. 3.Electron beam welding.
附录 附录A Braking system function is to make the car driving in accordance with the requirements of the pilot required even slow down park; They offend car has in various road conditions (including in the slope stability) in car; Make the downhill cars speed to be stable. For car up the role of brake is only in the car and role with the direction of the car driving direction opposite forces, and the size of these forces are random, do not control, so cars must be installed on a series of special equipment to achieve the function. Automobile brake system is to point to to ensure that the car in technology, improve the safe driving car average speed, etc., and the admiration installed in the car brake special brake institutions. In general automobile brake system including crane brake system and parking brake two sets of independent device. One crane brake device is a driver with feet to manipulate, and it said the foot brake. Parking brake device is a pilot with the hand, so it says of the manipulation of the hand brake. The function of the crane brake system is to make the car slow down or running in the shortest distance parking within. And parking brake function is to make had stopped the car on the road all keep still. But, sometimes, in an emergency, two braking device can be used at the same time and increase the effect of auto brake. Some special purpose of cars and often in the mountains cars, long and frequently brake will lead to crane brake system overheating, so in these cars often add all sorts of different types of auxiliary braking equipment, so as to speed up the hill stability. According to the braking energy situation, brake system can also be divided into human brake system, power brake system, and servo brake system, three. Human brake system to the driver's physical strength as braking energy; Power brake system engine power to the transformation of the air pressure or hydraulic braking energy as; And servo brake system is the most human and engine power as a brake energy. In addition, according to the braking energy transfer mode, brake system and can be divided into mechanical and hydraulic, pneumatic type and assolenoid style wait until a few kinds.
机械设计理论 机械设计是一门通过设计新产品或者改进老产品来满足人类需求的应用技术科学。它涉及工程技术的各个领域，主要研究产品的尺寸、形状和详细结构的基本构思，还要研究产品在制造、销售和使用等方面的问题。 进行各种机械设计工作的人员通常被称为设计人员或者机械设计工程师。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的基础知识。如前所诉，机械设计的目的是生产能够满足人类需求的产品。发明、发现和科技知识本身并不一定能给人类带来好处，只有当它们被应用在产品上才能产生效益。因而，应该认识到在一个特定的产品进行设计之前，必须先确定人们是否需要这种产品。 应当把机械设计看成是机械设计人员运用创造性的才能进行产品设计、系统分析和制定产品的制造工艺学的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以在一个好的设计中做出所需的全部决定的。另一方面，应该认真精确的进行所有运算。例如，即使将一个小数点的位置放错，也会使正确的设计变成错误的。 一个好的设计人员应该勇于提出新的想法，而且愿意承担一定的风险，当新的方法不适用时，就使用原来的方法。因此，设计人员必须要有耐心，因为所花费的时间和努力并不能保证带来成功。一个全新的设计，要求屏弃许多陈旧的，为人们所熟知的方法。由于许多人墨守成规，这样做并不是一件容易的事。一位机械设计师应该不断地探索改进现有的产品的方法，在此过程中应该认真选择原有的、经过验证的设计原理，将其与未经过验证的新观念结合起来。 新设计本身会有许多缺陷和未能预料的问题发生，只有当这些缺陷和问题被解决之后，才能体现出新产品的优越性。因此，一个性能优越的产品诞生的同时，也伴随着较高的风险。应该强调的是，如果设计本身不要求采用全新的方法，就没有必要仅仅为了变革的目的而采用新方法。 在设计的初始阶段，应该允许设计人员充分发挥创造性，不受各种约束。即使产生了许多不切实际的想法，也会在设计的早期，即绘制图纸之前被改正掉。只有这样，才不致于堵塞创新的思路。通常，要提出几套设计方案，然后加以比较。很有可能在最后选定的方案中，采用了某些未被接受的方案中的一些想法。
浅谈差速器 普通行星齿轮差速器由行星架（差速器壳），半轴齿轮等零件组成。它将发动机的动力，直接驱动差速器壳体内的轴，再由行星齿轮驱动左、右两半轴，并分别驱动左、右车轮。差速器的设计应满足：左半轴转速与右半轴转速之和等于两倍的行星架转速。当两侧车轮以纯滚动的形式做等距行驶时，会减少轮胎和路面的摩擦.差速器的这种调整是自动的，这里涉及到“最小能耗原理”，即地球上所有物体都倾向于耗能最小的状态。例如把一粒豆子放入一个碗内，豆子会自动停留在碗底，而不会留在碗壁，因为碗底是能量消耗最低的位置（位能），它会自动选择静止（动能最小）而不会不断地运动。同样的道理，汽车转弯时所有的驱动轮，左、右车轮与行星架的速度是相等的，而在汽车转弯时的三个平衡状态被破坏，导致内侧轮转速减小，横向轮RPM增加。 汽车差速器是驱动桥的主要部件。其功能是传递两侧半轴的动力，同时允许两半轴以不同的速度旋转，同时能够满足按照国家标准的自动的最低能量消耗的趋势，在转弯时自动接受转向半径来调整右轮转速，由于横向摩擦轮拖动现象，内侧车轮有滑动现象，现在两个驱动轮可以产生两个相反方向的附加力，因此符合最小的能源消耗原理, 这不可避免地导致了两侧车轮的速度差，从而摧毁了三个平衡关系，并通过半轴齿轮体现出来。迫使行星齿轮产生自转，使外侧半轴转速更快，内侧半轴减速，从而实现两侧车轮转速的差异。 如果任意一侧驱动轴上的驱动轮都使用一个整体的刚性连接，那么这两个轮子只能以相同的角度旋转。所以，当车辆的转向轮驱动时，由于外侧车轮比内侧车轮横过的距离大，将使外侧车轮在滚动的同时产生延迟，内侧车轮在滚动的同时产生滑动。即使车轮在凹凸不平的道路上跑直线，因为虽然道路是直，但轮胎滚动半径范围（轮胎制造误差，磨损不同，通过不均或气压不等所造成的车轮滑动）轮毂时，不仅会加剧轮胎的磨损滑动，增加动力性和燃油消耗，还能使车辆的转向困难，制动性能变得差.为了使车轮尽可能不会发生滑动的结构，必须保证车轮可以以不同的角度旋转。 轴间差速器：通常驾驶的轿车轮毂轴承支撑在主轴上，能够以任何角度旋转，驱动车轮分别与两根半轴刚性连接，在两根半轴之间有一个差速器，这种差速器称为轴间差速器。 如果使后轮轴成为一个整体，他将无法使两侧的车轮转速有差异，即不能做自动调整。为了解决这个问题，早在一百年前，法国雷诺汽车公司创始人路易斯·雷诺设计了一个差速器。 现代汽车上的差速器通常是根据其工作特性分为齿轮式差速器和限滑差速器两大类。 1.开模差速器 诺基开模差速器的结构是典型的行星齿轮组的结构，只有太阳轮和小齿轮环外
毕业设计(论文)外文资料翻译 学院：机械工程学院 专业：机械设计制造及其自动化 姓名： 学号：XXXXXXXXXX 外文出处：《Computational Intelligence and (用外文写)Design》 附件： 1.外文资料翻译译文；2.外文原文。 注：请将该封面与附件装订成册。
附件1：外文资料翻译译文 基于微型计算机的步进电机控制系统设计 孟天星余兰兰 山东理工大学电子与电气工程学院 山东省淄博市 摘要 本文详细地介绍了一种以AT89C51为核心的步进电机控制系统。该系统设计包括硬件设计、软件设计和电路设计。电路设计模块包括键盘输入模块、LED显示模块、发光二极管状态显示和报警模块。按键可以输入设定步进电机的启停、转速、转向,改变转速、转向等的状态参数。通过键盘输入的状态参数来控制步进电机的步进位置和步进速度进而驱动负载执行预订的工作。运用显示电路来显示步进电机的输入数据和运行状态。AT89C51单片机通过指令系统和编译程序来执行软件部分。通过反馈检测模块，该系统可以很好地完成上述功能。 关键词：步进电机，AT89C51单片机，驱动器，速度控制 1概述 步进电机因为具有较高的精度而被广泛地应用于运动控制系统，例如机器人、打印机、软盘驱动机、绘图仪、机械式阀体等等。过去传统的步进电机控制电路和驱动电路设计方法通常都极为复杂，由成本很高而且实用性很差的电器元件组成。结合微型计算机技术和软件编程技术的设计方法成功地避免了设计大量复杂的电路，降低了使用元件的成本，使步进电机的应用更广泛更灵活。本文步进电机控制系统是基于AT89C51单片机进行设计的，它具有电路简单、结构紧凑的特点，能进行加减速，转向和角度控制。它仅仅需要修改控制程序就可以对各种不同型号的步进电机进行控制而不需要改变硬件电路，所以它具有很广泛的应用领域。 2设计方案 该系统以AT89C51单片机为核心来控制步进电机。电路设计包括键盘输入电路、LED显示电路、发光二极管显示电路和报警电路，系统原理框图如图1所示。 At89c51单片机的P2口输出控制步进电机速度的时钟脉冲信号和控制步进电机运转方向的高低电平。通过定时程序和延时程序可以控制步进电机的速度和在某一
Automobile Brake System The braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When stepping on the brakes, the driver commands a stopping force ten times as powerful as the force that puts the car in motion. The braking system can exert thousands of pounds of pressure on each of the four brakes. Two complete independent braking systems are used on the car. They are the service brake and the parking brake. The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the parking brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set. The brake system is composed of the following basic c omponents: the “master cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses” connect the master cylinder to the cylinders” located at each wheel. Brake fluid, specially designed to work in extreme conditions, fills the system. “Shoes” and “pads” are pushed by cylinders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car. The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder (Figure).
机械类外文翻译 塑料注塑模具浇口优化 摘要:用单注塑模具浇口位置的优化方法，本文论述。该闸门优化设计的目的是最大限度地减少注塑件翘曲变形，翘曲，是因为对大多数注塑成型质量问题的关键，而这是受了很大的部分浇口位置。特征翘曲定义为最大位移的功能表面到表面的特征描述零件翘曲预测长度比。结合的优化与数值模拟技术，以找出最佳浇口位置，其中模拟armealing算法用于搜索最优。最后，通过实例讨论的文件，它可以得出结论，该方法是有效的。 注塑模具、浇口位臵、优化、特征翘曲变形关键词: 简介 塑料注射成型是一种广泛使用的，但非常复杂的生产的塑料产品，尤其是具有高生产的要求，严密性，以及大量的各种复杂形状的有效方法。质量ofinjection 成型零件是塑料材料，零件几何形状，模具结构和工艺条件的函数。注塑模具的一个最重要的部分主要是以下三个组件集:蛀牙，盖茨和亚军，和冷却系统。拉米夫定、Seow(2000)、金和拉米夫定(2002) 通过改变部分的尼斯达到平衡的腔壁厚度。在平衡型腔充填过程提供了一种均匀分布压力和透射电镜,可以极大地减少高温的翘曲变形的部分～但仅仅是腔平衡的一个重要影响因素的一部分。cially Espe,部分有其功能上的要求,其厚度通常不应该变化。 pointview注塑模具设计的重点是一门的大小和位臵,以及流道系统的大小和布局。大门的大小和转轮布局通常被认定为常量。相对而言,浇口位臵与水口大小布局也更加灵活,可以根据不同的零件的质量。 李和吉姆(姚开屏,1996a)称利用优化流道和尺寸来平衡多流道系统为multiple 注射系统。转轮平衡被形容为入口压力的差异为一多型腔模具用相同的蛀牙,也存
驱动桥设计 随着汽车对安全、节能、环保的不断重视，汽车后桥作为整车的一个关键部件，其产品的质量对整车的安全使用及整车性能的影响是非常大的，因而对汽车后桥进行有效的优化设计计算是非常必要的。 驱动桥处于动力传动系的末端，其基本功能是增大由传动轴或变速器传来的转矩,并将动力合理地分配给左、右驱动轮，另外还承受作用于路面和车架或车身之间的垂直力力和横向力。驱动桥一般由主减速器、差速器、车轮传动装置和驱动桥壳等组成。 驱动桥作为汽车四大总成之一，它的性能的好坏直接影响整车性能，而对于载重汽车显得尤为重要。驱动桥设计应当满足如下基本要求： 1、符合现代汽车设计的一般理论。 2、外形尺寸要小，保证有必要的离地间隙。 3、合适的主减速比，以保证汽车的动力性和燃料经济性。 4、在各种转速和载荷下具有高的传动效率。 5、在保证足够的强度、刚度条件下，力求质量小，结构简单，加工工艺性 好，制造容易，拆装，调整方便。 6、与悬架导向机构运动协调，对于转向驱动桥，还应与转向机构运动协调。智能电子技术在汽车上得以推广使得汽车在安全行驶和其它功能更上一层楼。通过各种传感器实现自动驾驶。除些之外智能汽车装备有多种传感器能充分感知交通设施及环境的信息并能随时判断车辆及驾驶员是否处于危险之中，具备自主寻路、导航、避撞、不停车收费等功能。有效提高运输过程中的安全，减少驾驶员的操纵疲劳度，提高乘客的舒适度。当然蓄电池是电动汽车的关键，电动汽车用的蓄电池主要有：铅酸蓄电池、镍镉蓄电池、钠硫蓄电池、钠硫蓄电池、锂电池、锌—空气电池、飞轮电池、燃料电池和太阳能电池等。在诸多种电池中，燃料电池是迄今为止最有希望解决汽车能源短缺问题的动力源。燃料电池具有高效无污染的特性，不同于其他蓄电池，其不需要充电，只要外部不断地供给燃料，就能连续稳定地发电。燃料电池汽车(FCEV)具有可与内燃机汽车媲美的动力性能，在排放、燃油经济性方面明显优于内燃机车辆。
译文 流体传动及控制技术已经成为工业自动化的重要技术，是机电一体化技术的核心组成之一。而电液比例控制是该门技术中最具生命力的一个分支。比例元件对介质清洁度要求不高，价廉，所提供的静、动态响应能够满足大部分工业领域的使用要求，在某些方面已经毫不逊色于伺服阀。比例控制技术具有广阔的工业应用前景。但目前在实际工程应用中使用电液比例阀构建闭环控制系统的还不多，其设计理论不够完善，有待进一步的探索，因此，对这种比例闭环控制系统的研究有重要的理论价值和实践意义。本论文以铜电解自动生产线中的主要设备——铣耳机作为研究对象，在分析铣耳机组各构成部件的基础上，首先重点分析了铣耳机的关键零件——铣刀的几何参数、结构及切削性能，并进行了实验。用电液比例方向节流阀、减压阀、直流直线测速传感器等元件设计了电液比例闭环速度控制系统，对铣耳机纵向进给装置的速度进行控制。论文对多个液压阀的复合作用作了理论上的深入分析，着重建立了带压差补偿型的电液比例闭环速度控制系统的数学模型，利用计算机工程软件，研究分析了系统及各个组成环节的静、动态性能，设计了合理的校正器，使设计系统性能更好地满足实际生产需要 水池拖车是做船舶性能试验的基本设备,其作用是拖曳船模或其他模型在试验水池中作匀速运动,以测量速度稳定后的船舶性能相关参数,达到预报和验证船型设计优劣的目的。由于拖车稳速精度直接影响到模型运动速度和试验结果的精度,因而必须配有高精度和抗扰性能良好的车速控制系统,以保证拖车运动的稳速精度。本文完成了对试验水池拖车全数字直流调速控制系统的设计和实现。本文对试验水池拖车工作原理进行了详细的介绍和分析,结合该控制系统性能指标要求,确定采用四台直流电机作为四台车轮的驱动电机。设计了电流环、转速环双闭环的直流调速控制方案,并且采用转矩主从控制模式有效的解决了拖车上四台直流驱动电机理论上的速度同步和负载平衡等问题。由于拖车要经常在轨道上做反复运动,拖动系统必须要采用可逆调速系统,论文中重点研究了逻辑无环流可逆调速系统。大型直流电机调速系统一般采用晶闸管整流技术来实现,本文给出了晶闸管整流装置和直流电机的数学模型,根据此模型分别完成了电流坏和转速环的设计和分析验证。针对该系统中的非线性、时变性和外界扰动等因素,本文将模糊控制和PI控制相结合,设计了模糊自整定PI控制器,并给出了模糊控制的查询表。本文在系统基本构成及工程实现中,介绍了西门子公司生产的SIMOREGDC Master 6RA70全数字直流调速装置,并设计了该调速装置的启动操作步骤及参数设置。完成了该系统的远程监控功能设计,大大方便和简化了对试验水池拖车的控制。对全数字直流调速控制系统进行了EMC设计,提高了系统的抗干扰能力。本文最后通过数字仿真得到了该系统在常规PI控制器和模糊自整定PI控制器下的控制效果,并给出了系统在现场调试运行时的试验结果波形。经过一段时间的试运行工作证明该系统工作良好,达到了预期的设计目的。 提升装置在工业中应用极为普遍,其动力机构多采用电液比例阀或电液伺服阀控制液压马达或液压缸,以阀控马达或阀控缸来实现上升、下降以及速度控制。电液比例控制和电液伺服控制投资成本较高,维护要求高,且提升过程中存在速度误差及抖动现象,影响了正常生产。为满足生产要求,提高生产效率,需要研究一种新的控制方法来解决这些不足。随着科学技术的飞速发展,计算机技术在液压领域中的应用促进了电液数字控制技术的产生和发展,也使液压元件的数字化成为液压技术发展的必然趋势。本文以铅电解残阳极洗涤生产线中的提升装置为研究
毕业设计（论文）外文文献翻译 文献、资料中文题目：汽车制动系统 文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业：汽车检测与维修 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14
Automobile Brake System The braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When stepping on the brakes, the driver commands a stopping force ten times as powerful as the force that puts the car in motion. The braking system can exert thousands of pounds of pressure on each of the four brakes. Two complete independent braking systems are used on the car. They are the service brake and the parking brake. The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set. The brake system is composed of the following basic components: the “master cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses” connect the master cylinder to the “slave cylinders” located at each wheel. Brake fluid, specially designed to work in extreme conditions, fills the system. “Shoes” and “pads” are pushed by the slave cy linders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car. The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder (Figure). Basically, all car brakes are friction brakes. When the driver applies the
近几年，我厂和英国、西班牙的几个公司有业务往来，外商传真发来的图纸都是英文标注，平时阅看有一定的困难。下面把我们积累的几点看英文图纸的经验与同行们交流。 1标题栏 英文工程图纸的右下边是标题栏（相当于我们的标题栏和部分技术要求），其中有图纸名称（TILE）、设计者（DRAWN）、审查者（CHECKED）、材料（MATERIAL）、日期（DATE）、比例（SCALE）、热处理（HEAT TREATMENT）和其它一些要求，如： 1)TOLERANCES UNLESS OTHERWISE SPECIFIAL 未注公差。 2)DIMS IN mm UNLESS STATED 如不做特殊要求以毫米为单位。 3)ANGULAR TOLERANCE±1°角度公差±1°。 4)DIMS TOLERANCE±0.1未注尺寸公差±0.1。 5)SURFACE FINISH 3.2 UNLESS STATED未注粗糙度3.2。 2常见尺寸的标注及要求 2.1孔（HOLE）如： （1）毛坯孔：3"DIAO+1CORE 芯子3"0+1; （2）加工孔：1"DIA1"; （3）锪孔：锪孔(注C＇BORE=COUNTER BORE锪底面孔); （4）铰孔：1"/4 DIA REAM铰孔1"/4; （5）螺纹孔的标注一般要表示出螺纹的直径，每英寸牙数（螺矩）、螺纹种类、精度等级、钻深、攻深，方向等。如： 例1.6 HOLES EQUI-SPACED ON 5"DIA (6孔均布在5圆周上（EQUI-SPACED=EQUALLY SPACED均布） DRILL 1"DIATHRO＇ 钻1"通孔（THRO＇=THROUGH通） C/SINK22×6DEEP 沉孔22×6 例2.TAP7"/8-14UNF-3BTHRO＇ 攻统一标准细牙螺纹，每英寸14牙，精度等级3B级 （注UNF=UNIFIED FINE THREAD美国标准细牙螺纹） 1"DRILL 1"/4-20 UNC-3 THD7"/8 DEEP 4HOLES NOT BREAK THRO钻 1"孔，攻1"/4美国粗牙螺纹，每英寸20牙，攻深7"/8,4孔不准钻通（UNC=UCIFIED COARSE THREAD 美国标准粗牙螺纹）
英文原文 Introductions to Control Systems Automatic control has played a vital role in the advancement of engineering and science. In addition to its extreme importance in space-vehicle, missile-guidance, and aircraft-piloting systems, etc, automatic control has become an important and integral part of modern manufacturing and industrial processes. For example, automatic control is essential in such industrial operations as controlling pressure, temperature, humidity, viscosity, and flow in the process industries; tooling, handling, and assembling mechanical parts in the manufacturing industries, among many others. Since advances in the theory and practice of automatic control provide means for attaining optimal performance of dynamic systems, improve the quality and lower the cost of production, expand the production rate, relieve the drudgery of many routine, repetitive manual operations etc, most engineers and scientists must now have a good understanding of this field. The first significant work in automatic control was James Watt’s centrifugal governor for the speed control of a steam engine in the eighteenth century. Other significant works in the early stages of development of control theory were due to Minorsky, Hazen, and Nyquist, among many others. In 1922 Minorsky worked on automatic controllers for steering ships and showed how stability could be determined by the differential equations describing the system. In 1934 Hazen, who introduced the term “ervomechanisms”for position control systems, discussed design of relay servomechanisms capable of closely following a changing input. During the decade of the 1940’s, frequency-response methods made it possible for engineers to design linear feedback control systems that satisfied performance requirements. From the end of the 1940’s to early 1950’s, the root-locus method in control system design was fully developed. The frequency-response and the root-locus methods, which are the