附录
Control of a Non-Orthogonal Reconfigurable Machine Tool
Reuven KatzJohn YookYoram Koren
Received: January 3, 2003; revised: September 16, 2003
Abstract
Computerized control systems for machine tools must generate coordinated movements of the separately driven axes of motion in order to trace accurately a predetermined path of the cutting tool relative to the workpiece. However, since the dynamic properties of the individual machine axes are not exactly equal, undesired contour errors are generated. The contour error is defined as the distance between the predetermined and actual path of the cutting tool. The cross-coupling controller (CCC) strategy was introduced to effectively decrease the contour errors in conventional, orthogonal machine tools. This paper, however,deals with a new class of machines that have non-orthogonal axes of motion and called reconfigurable machine tools (RMTs). These machines may be included in large-scale reconfigurable machining systems (RMSs).When the axes of the machine are non-orthogonal, the movement between the axes is tightly coupled and the importance of coordinated movement among the axes becomes even greater. In the case of a non-orthogonal RMT, in addition to the contour error, another machining error called in-depth error is also generated due to the non-orthogonal nature of the machine. The focus of this study is on the conceptual design of a new type of cross-coupling controller for a non-orthogonal machine tool that decreases both the contour and the in-depth machining errors.Various types of cross-coupling controllers, symmetric and non-symmetric, with and without feedforward, are suggested and studied. The stability of the control system is investigated, and simulation is used to compare the different types of controllers. We show that by using cross-coupling controllers the reduction of machining errors are significantly reduced in comparison with the conventional de-coupled controller. Furthermore, it is shown that the non-symmetric cross-coupling feedforward (NS-CC-FF) controller demonstrates the best results and is the leading concept for non-orthogonal machine tools. ?2004 ASME
Contributed by the Dynamic Systems, Measurement, and Control Division of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT, AND
CONTROL. Manuscript received by the ASME Dynamic Systems and Control Division January3, 2003; final revision September 16, 2003. Associate Editor: J.Tu.
Keywords:machine tool, cross-coupling controller, non-orthogonal, RMT
1 Introduction
Currently manufacturing industries have two primary methods for producing medium and high volume machined parts: dedicated machining systems (DMSs) and flexible manufacturing systems (FMSs) that include CNC machines. The DMS is an ideal solution when the part design is fixed and mass production is required to reduce cost. On the other hand, the FMS is ideal when the required quantities are not so high and many modifications in the part design are foreseen. In contrast to these two extremes, Koren describes an innovative approach of customized manufacturing called reconfigurable manufacturing systems (RMS). The main advantage of this new approach is the customized flexibility in the system to produce a "part family" with lower investment cost than FMS. A typical RMS includes both conventional CNC machines and a new type of machine called the Reconfigurable Machine Tool . The Engineering Research Center (ERC) for Reconfigurable Machining Systems (RMS) at the University of Michigan with its industrial partners has designed an experimental Reconfigurable Machine Tool (RMT) 。This machine allows ERC researchers to validate many of the new concepts and machine tool design methodologies that have been already developed in the center. There are many types of RMTs. This paper describes an arch-type non-orthogonal multi-axis RMT machine 。The economic justification of RMTs is given in section 2 of this paper.
A contouring motion requires that the cutting tool moves along a desired trajectory. Typically, computerized control systems for machine tools generate coordinated movements of the separately driven axes of motion in order to trace a predetermined path of the cutting tool relative to the workpiece. To reduce the contouring error, which is defined as the distance between the predetermined and the actual path, there have been two main control strategies. The first approach is to use feedforward control in order to reduce axial tracking errors .however, they are limited when non-linear cuts are required. The other approach is to use cross-coupling control in which axial-feedback information is shared between the moving axes. The cross-coupling controller is used in addition to the conventional axial servo controller. At each sampling time, the cross-coupling controller calculates the current contour error and generates a command that moves the tool toward the closest point on the desired tool path. This control strategy of the cross-coupling controller (CCC) effectively decreases the contour error. Advanced control methods have been applied to further improve the control properties of the original cross-coupling controller (CCC). An optimal CCC is suggested in , to improve the controller performance when high contouring speeds were required. Another method to overcome the same problem for higher contour feedrates is addressed in , which uses adaptive feederate control strategy to improve the controller performance. The latest trend of cross-coupling controller improvement is the application of fuzzy logic . All these
methods, however, do not work for machines with non-orthogonal axes.Surface cut (e.g., a circular cut in the X-Y plane) on a 3-axis orthogonal milling machine requires a motion of two axes (e.g., X and Y). However, surface cuts in the non-orthogonal RMT require simultaneous motion of all three axes. Therefore, in addition to the contour error, this motion creates another error, called the in-depth error, which is in the Z direction. This error affects the surface finish quality of the workpiece. While contouring, the tool tip of the RMT has not only to follow the predetermined path, but also to control continuously the depth of cut. The simultaneous control of both errors, the conventional contour error and the in-depth error, requires a new control strategy since the standard CCC algorithms cannot be directly applied. In other words, the RMT control design problem requires a new control approach that is able to correct simultaneously two types of cutting errors. This problem has not been addressed in the literature.
In this paper, we describe three types of controllers aimed at reducing the contour and in-depth error simultaneously. First we investigate a symmetrical cross-coupling (S-CC) controller, which unfortunately does not show good performance in reducing both errors. The poor performance is due to the conflicting demands in reducing the two errors and the lack of information sharing between the two pairs of axes (X-Y and Y-Z), which are responsible for error compensation. To overcome this problem, the required motion information of one pair of axes is fed forward to the other. This idea results in two new controller types, symmetrical cross-coupling feedforward (S-CC-FF) controller and non-symmetrical cross-coupling feedforward (NS-CC-FF) controller. Finally, the influence of the reconfigurable angular position of the cutting tool on system stability is investigated.
2 Machine Characteristics and the Control Problem
In this section we explain the economic advantage of the RMT, and develop the mathematical representation of the contour error and the in-depth error.
a Machine Characteristics
Typical CNC machine tools are built as general-purpose machines. The part to be machined has to be adapted to a given machine by utilizing process planning methodologies. This design process may create a capital waste: Since the CNC machine is designed at the outset to machine any part (within a given envelope), it must be built with general flexibility, but not all this flexibility is utilized for machining a specific part. The concept of RMTs reverses this design order: The machine is designed around a known part family. This design process creates a less complex, although less flexible machine, but a machine that contains all the functionality and flexibility needed to produce a certain part family. The RMT may contain, for example, a smaller number of axes, which reduces cost and enhances the machine reliability. Therefore, in principle, a RMT with customized flexibility would be less expensive than a comparable CNC that has general flexibility.
A conceptual example of a RMT designed to machine a part with inclined surfaces of 45 deg is shown in Fig. 1. If a conventional CNC is used to machine this inclined surface, a 4- or 5-axis machine is needed. In this example, however, only three axes are needed on a new type of 3-axis non-orthogonal machine tool. Nevertheless, one may argue that it's not economical to build as product non-orthogonal machine tools for 45 deg. Therefore, we developed a 3-axis non-orthogonal machine in which the angle of the Z-axis is adjustable during reconfiguration periods, as shown in Fig. 2. The simple adjusting mechanism is not servo-controlled and does not have the requirements of a regular moving axis of motion.
The designed RMT may be reconfigured into six angular positions of the spindle axis, between –15 and 60 deg with steps of 15 deg. The main axes of the machine are X-axis (table drive horizontal motion), Y-axis (column drive vertical motion) and
Z-axis (spindle drive inclined motion) . The two extreme positions of the machine spindle axis (–15 and 60 deg) . The XYZ machine axes comprise a non-orthogonal system of coordinates, except for the case when the spindle is in a horizontal position. Two orthogonal auxiliary systems of coordinates are used to describe the machine, XSZ and XYZ, where S is an axis parallel to the part surface and Z is an axis perpendicular to both X and Y-axis.
The machine is designed to drill and mill on an inclined surface in such a way that the tool is perpendicular to the surface. In milling at least two axes of motion participate in the cut. For example, the upward motion on the inclined surface in the S-axis direction requires that the machine drive move in the positive Y direction (upward) and in the positive Z direction (downward). When milling a nonlinear contour (e.g., a circle) on the inclined surface of the RMT, we may expect to get the traditional contour error. This error is measured on the workpiece surface (X-S plane) relative to the predetermined required path of the tool. However, in our machine, we get additional cutting error at the same time. This error is created due to the fluctuations in the depth of cut as result of the combined motion in the Y and Z-axis and therefore we call it "in-depth error." This combined motion is required in order to move the tool up and down along the inclined surface. Figure 4 describes three systems of coordinates. XYZ is the machine tool non-orthogonal system of coordinates where the table moves in X direction, Y is the motion along the column and Z is in the direction of the spindle and the cutting tool. XSZ is an auxiliary orthogonal system of coordinates where S is the direction of the inclined surface of the workpiece, which is perpendicular to the tool axis. XYZ is another auxiliary orthogonal system of coordinates where Z is horizontal.
b Contouring and In-Depth Errors
To overcome the combined error, we designed a special cross-coupling controller. In the present paper, we would like to explain some aspects of the controller design. This design of a new cross-coupling controller for the 3-axes of motion gives insight to the system behavior under external disturbances.
In-depth Error
The in-depth error is typical to the characteristics of our non-orthogonal machine. In order to cut the workpiece at a predetermined depth,the combined motion of both Y and Z-axis must be controlled. As a result of the position errors of the servomotor drives due to the external disturbances on each axis the in-depth error is generated. This error may affect significantly the quality of the surface finish. The in-depth error is described in describes the linear relation between the error components in the Y and Z directions.It is important to understand that this error is not only time dependent but also depends on the machine reconfiguration angular position. For each angle of spindle axis positioning, the controller will apply different value of C zy in equation
3 Controllers Design
In traditional orthogonal CNC machines, the cross-coupling control strategy effectively reduces the error between the predetermined tool path and the actual tool path. In a two-axis contouring system, the X-axis servodrive receives two inputs: one a traditional input from an X-axis servo controller that reduces Ex (the axial position error along the X direction) and another input from the cross-coupling controller to reduce rx (the X component of the contour error). Similarly, the Y-axis plant receives two inputs. The additional inputs to each axis are used to decrease the contour error in the normal direction represented by r
The objective of this paper is to suggest a suitable cross-coupling control strategy for both the contour and in-depth errors. Three controllers are examined: a symmetric cross-coupling (S-CC) controller, the symmetric cross-coupling controller with additional feedforward (S-CC-FF), and a non-symmetric cross-coupling controller with feedforward (NS-CC-FF).
a Controllers Structures.
The detailed structure of the three controllers is illustrated The basic structure is to have two standard cross-coupling (CC) controllers, one for the contour error in the XY-subsystem with a gain Gr and the other for the in-depth error in the YZ-subsystem with a gain Gz. Section 4b includes a discussion on the values of Gr and Gz. The in-depth cross-coupling controller has the same basic control structure as the contour cross-coupling controller. In addition, a feedforward term may be used to inform the Z-axis about the additional Y-axis input caused by the contour cross-coupling controller. "Knowing" this information in advance, the Z-axis can compensate for the movement of the Y-axis in order to reduce the in-depth error. The differences among the three proposed controllers are: (a) the presence or absence of a
feedforward term (In the S-CC controller, the Kff block does not exist), and (b) a difference in the direction of the controlling error (in the NS-CC-FF controller, Czy is zero). If the feedforward term exists, Kff in Figure 6 can be expressed as follows
The tracing error estimation gains, Crx, Cry, Czy, Czz are given in Equations (1) and (2). The symmetric cross-coupling (S-CC) controller uses the contour cross-coupling controller between the X and Y-axis and the in-depth cross-coupling controller between the Y and Z-axis. The contour cross-coupling controller decreases the contour error by coupling the X and Y-axis movements while the in-depth cross-coupling controller compensates the in-depth error by coupling the Y and Z-axis movements. The Y-axis receives one output from each cross-coupling controller; Ury and Uzy. As briefly explained in the previous section, Ury and Uzy may be in conflict with each other and the resulting control action does not necessarily decrease both the contour and the in-depth error. This is the main drawback of the SCC controller and it will be further investigated in the stability section.
The symmetric cross-coupling feedforward (S-CC-FF) controller has the same structure as the S-CC controller, but includes an additional feedforward term. This feedforward term gives the Z-axis information about the movement of the Y-axis. In other words, when an output from the contour cross-coupling controller is applied to the Y-axis, this additional input is fed to the Z-axis in order to reduce the in-depth error from that additional input to Y-axis. Even though the S-CC-FF controller improves the performance of the system by adding a feedforward term, the conflict between the cross-coupling controllers still exists. Again, this characteristic will be discussed in more detail in the stability section. This is the motivation for introducing the next controller.
The non-symmetric cross-coupling feedforward (NS-CC-FF) controller is suggested in order to remove the coupling between the cross-coupling controllers. Even though the in-depth error depends on the performance of the Y and Z-axis, this error is always parallel to the Z-axis movement. Using this characteristic we convert the controller to a master (Y)-slave (Z) operation in which the controller moves only the Z-axis to decrease the in-depth error. Namely, the coupling between the contour cross-coupling controller and the in-depth cross-coupling controller is removed in the NS-CC-FF controller. Therefore, Y-axis servo drive receives only one output from the cross-coupling controllers. As will be shown later this controller has the best performance.
4 Controllers Stability Analysis
The RMT system has tightly coupled axes and contains time-varying sinusoidal parameters. In order to simplify the stability analysis, the following assumption was
made: E, where , E, are contour error, axial error, and radius of curvature, respectively [15]. With this assumption, for the stability analysis, we can approximate the sinusoidal gains by linear terms. Furthermore, in order to eliminate the complexity with time-varying parameters in the stability analysis, we analyze the linearized contouring system since the cross-controller gains, Crx, Cry, Czy and Czz are constants in this case. The analysis below shows that there are bounded stability regions, and the controller parameters must be selected to satisfy certain constraints in order for the system to be stable.
a. Characteristic Equations of S-CC, S-CC-FF, and NS-CC-FF Controllers
For the linear system, = A·X + B·U, Y = C·X + D·U, the transfer function from U to Y, which is C(sI-A)–1B + D, should be examined for the stability of the system. However, if C and D are BIBO matrix, then (sI-A)–1B can be used for the stability analysis. Since the C and D matrices for the contour and in-depth error of the RMT are bounded time varying gain matrices, the stability of each axis can be used for the stability analysis of the entire system. For S-CC controller the positions of each axis are given as follows
The notations Px, Py, Pz indicate the positions of the X, Y, Z-axis, respectively. Xr, Yr, Zr are the reference signals for each axis, and Ex, Ey, Ez are the errors (Ex = Xr–Px). For the S-CC-FF controller the positions are
Namely, the characteristic equation of the X-axis, is the same in all three controllers. However, the characteristic equations of the Y and Z-axis depend on the type of controller used. In order to simplify the analysis the stability analysis is done for a given stable servo controllers for each axis and we investigate the stability of the system due to the cross-coupling controllers, Gr and Gz, only.
b Stable Region of the Cross-Coupling Controllers
The characteristic equations obtained in the previous section depend not only on the variable gain, C's, but also on the RMT configuration angle, . Furthermore, the
characteristic equation for Y with the S-CC and S-CC-FF controllers exhibit coupling between the contour and in-depth cross-coupling controllers. In order to simplify the analysis, PI controller for Gr and P controller for Gz are used
Numeric values of the parameters used in this study to describe the servo controllers and the plants are presented in appendix A. Utilizing these values, the characteristic equation can be expressed in terms of WP, WI, WZ, C's, and . First,
the configuration of the RMT system is fixed at = 60°, and the characteristic
equation is calculated as function of WP, WI, WZ, and C's. Using the Routh-Jury criteria, the stable regions of WP, WI, and WZ are obtained as a function of C's, and the smallest intersection of the stable regions with respect to C's values was obtained. In addition, two sampling periods were considered, Ts = 10 msec and Ts = 1 msec. One typical stability plot for Wz = 10 and = 60°, is shown in Fig. 7. The stability
analysis results may be summarized as follows:
1 The stable region for S-CC and S-CC-FF controllers is an area bounded by three lines (as shown in Fig. 7): Line 1, Line 2, and Line 3 while the stable region for NS-CC-FF controller is the area bounded by Line 1 and Line 3.
2 For higher values of the gain Wz, Line 2 moved to the left while Line 1 and Line
3 were not affected by varying Wz. It means that a higher value of the proportional controller gain Wz, will reduce the stability region.
3 For higher values, Line 2 moves to the right while Line 1 and Line 3 are not
affected. However, Line 2 can never cross Line 3 by only varying . The meaning of
this observation is that horizontal spindle position represents better stability of the system.
4 The stability region becomes smaller with increasing sampling period.
The system with the NS-CC-FF controller has the largest stable region for WP, WI, and WZ. This is due to the fact that the conflict between the cross-coupling controllers has been removed by decreasing the in-depth error by Z-axis movement only. The conflict between the cross-coupling controller in S-CC and S-CC-FF controller can be seen in the transfer function shown in Eqs. (4) and (5). The subsystem for the contour error, which consists of X and Y-axis only, should contain only variables related to the X and Y-axis such as Ex, Ey, Xr, and Yr. However, this subsystem contains also an Ez term. This Ez term will act as a disturbance to the contour subsystem.
Similarly, the subsystem for the in-depth error, which consists of Y and Z-axis only, should be composed of terms related to the Y and Z-axis. Again, the in-depth subsystem contains an Ex term which will act as a disturbance to this subsystem. Unlike the transfer function of the Z-axis in Eq. (4), the one in Eq. (5) contains a feedforward term Kff. This Kff reduces the disturbance to the system resulting in a better performance for the S-CC-FF than the S-CC controller. Considering the transfer functions for the NS-CC-FF controller shown in Eq. (6), the subsystem for the contour error contains only terms related to the X and Y-axis and the subsystem for the in-depth error contains a feedforward term Kff that compensates the disturbance term. In other words, the disturbance term from the contour cross-coupling controller to the in-depth cross-coupling controller was removed using the feedforward term. Also the disturbance term from the in-depth cross-coupling controller to the contour cross-coupling controller was removed by correcting the in-depth error by only moving the Z-axis. Overall, the performance of the system using NS-CC-FF controller is expected to be the best among the proposed controllers, and the simulation results support this analysis.
5 Simulation Results
The simplified RMT axial model that was used in the simulation (the parameters for each axis can be found in appendix A). The cross-coupling controller parameters were chosen such that the system will operate within the stable region defined in the previous section. These parameters are not the optimal since optimization of the controller, was not a goal of this paper. For comparison purposes, all cross-coupling controller parameters are kept the same throughout the simulation. The desired tool path is a circular motion on the inclined X-S plane, and the response of each controller to a disturbance is compared.
6 Conclusions
The conceptual design process of crossed-coupling controllers that was described in the paper allows insight and better understanding of the RMT controller problem. Some machining processes that traditionally require four or 5 degrees-of-freedom using an orthogonal CNC machine, may be performed by a new machine-type—the reconfigurable machine tool (RMT) that has just three-degrees of freedom. The disadvantage of the RMT configuration is that when contour cuts are needed in the X-S plane, a new type of error—the in-depth error—may occur. This error, if not controlled properly, may severely affect the surface finish of the machined surfaces. To reduce the effect of the in-depth error, we introduced three types of cross-coupling controllers and found that all three are stable for a reasonable range of parameters. An
increase of the reconfiguration angle (or tool-positioning angle) increases the contour and in-depth errors and decreases the region of stability.
Furthermore, we also found that all three types of cross-coupling (CC) controllers reduce significantly the contour and in-depth errors. It was shown that for the control of the nonorthogonal arch-type RMT, the nonsymmetric cross-coupling feed-forward (NS-CC-FF) controller has the best performance of the three CC controllers. The symmetric cross-coupling (S-CC) controller does not adequately solve the in-depth error problem-an error that is typical to non-orthogonal RMTs. The S-CC-FF controller is marginally acceptable, but has problems when a disturbance (such as a cutting force) is applied to the Z-axis. Only the NS-CC-FF controller reduces significantly both the contour and the in-depth errors. Furthermore, the stability analysis shows that the NS-CC-FF controller is stable for a wider range of parameters than the other controllers are. Our main conclusion is, therefore, that the NS-CC-FF controller best fits the arch-type RMT. Nevertheless, we cannot state that it is a general conclusion for all types of RMTs.
References
[1] Coker SA, Shin YC. In-process control of surface roughness with tool
wear via ultrasonic sensing. In: Proceedings of American control
conference, Seattle; 1995.
[2] Lauderbaugh LK, Ulsoy AG. Model reference adaptive force control
in milling. ASME J Eng Ind 1989.
[3] Kim TY, Kim J. Adaptivecutting force controlfor a machining center byusingindirectcuttingforcemeasurements.IntJ MachToolsManuf
1996
[4] Masory O, Koren Y. Variable-gain adaptive control systems for
machine tools. J Manuf Syst 1983.
[5] Elbestawi MA, Mohamed Y, Liu L. Application of some parameter
adaptive control algorithms in machining. ASME J Dyn Syst Meas
Control 1990;
[6] Ulsoy AG, Koren Y. Control of machining processes. ASME J Dyn
Syst Meas Control 1993
[8] Park J, Ulsoy A. On-line tool wear estimation using force measure-
ment and a nonlinear observer. ASME J Dyn Sys Meas Control
1992
[9] Glass K, Colbaugh R. Real-time tool wear estimation using cutting
force measurements. In: Proceedings of the 1996 IEEE international
conference on robotics and automation; 1996
[10] Li X, Li HX, Guan XP, Du R. Fuzzy estimation of feed-cutting force
from current measurement–A case study on intelligent tool wear
condition monitoring. IEEE Trans Syst Man Cybernet – Part
2004;
非正交可重组机床的控制
摘要
为了准确预定刀具相对于工件的轨迹，机床计算机控制系统必须协调各运动机构运转轴的动作。不过,由于各机械轴的运动轨迹不尽相同的情况下,产生了偶然的误差。误差的范围是指与刀具实际预定轨迹的距离。交叉耦合控制(CCC)战略的实施,有效地减少了正交机床常规误差范围。这篇文章,涉及一类新的非正交可
重组机床(RMTs)。这种机床可列入大规模可重组加工系统(RMSS)。当机械轴非正交时，轴线之间的运动必须是紧密结合，各运动轴协调的重要性变得更大。在非正交可重组机床加工中,除了形状误差之外,加工误差也是非正交机床引起的。这项研究的重点是减少新型交叉耦合控制的非正交机床形状和加工误差的概念设计。各种交叉耦合控制,对称和非对称,有没有前馈,是需要研究的。控制系统的稳定性调查,使用模拟比较不同类型控制。我们证明与传统的去耦控制相比用交叉耦合控制时，机械误差大为减少。此外,它显示了非对称交叉耦合前馈(NS-CC-FF)控制显示最好成绩是主要的概念和非正交机床。
关键词：机床刀具，交叉耦合控制，非正交，可重组加工系统
1.概述
目前制造行业中主要有两种进行批量生产的方法:加工专用系统(DMSS)和数控柔性制造系统。DMS是一个理想的在设计、量产定需降低成本时的解决方法。另一方面,FMS是在零件设计要求不是很高,数量很多时的理想方法。与这两个极端相比,Koren描述了一种要求可重组设计制造制造系统(RMS)的新办法。这
一新方法的主要优点是灵活性系统设计制作了比FMS投资成本低的"零件库"。典型的RMS一般包括传统的和可重组的新型数控机床。美国密西根大学可重组加工系统(RMS)工程研究中心(ERC)与产业合作伙伴设计了实验用可重组机床(RMT)。这种机床使ERC研究中心的研究人员机床设计和验证方法得到了发展。有许多种RMTs。这篇文章主要是描述原型非正交多轴RMT机床。RMTs的经济因素在本文的第二部分给出。
做等直线运动的要求规定刀具要沿着理想的轨迹运动。通常,机床的计算机控制系统各轴的协调运动议案是为了追踪相对于刀具的预定的轨迹。为了减少造型错误,即指在预定的和实际的轨迹。有两个主要的控制策略。第一种方式是使用前馈控制,以减少实验跟踪误差。然而，当需要非线性切削时他们是有限的。其他方法是使用交叉耦合控制实验中移动轴共享的反馈信息。除了使用在传统伺服控制轴之外，交叉耦合控制还被使用着。每次采样时，交叉耦合控制计算当前形状误差,并产生指导刀具沿着预定轨迹运动的指令。这种交叉耦合控制（CCC）的控制策略有效地减少了误差范围。先进的控制方法已应用于使原有交叉耦合控制(CCC)的控制性能更进一步提高。当要求高速度时，最佳的（CCC）建议改善控制性能。另一种克服形状高馈送率这个问题的方法,是用适应的馈送率控制策略,以提高控制性能。最新趋势交叉耦合控制改善即为应用模糊逻辑。但是，所有这些方法都不用于非正交轴线机床。在三轴正交铣床上的表面切削(如，在X-Y 坐标面的循环切削)需要两个坐标轴的坐标运动(如X和Y)。然而,在非正交RMT 内的表面切削同时要求三轴坐标。因此,除了形状误差之外,这造成了另一种在Z 方向的叫作深度误差的误差。这个误差影响工件表面的完成质量。而RMT的刀具尖端造型,不仅遵循预定的轨迹,而且也控制着不断降低的切削深度。要同时控制误差,常规误差范围和深度误差,就需要有新的策略,这是因为控制中心的标准算法不能直接使用。换言之,RMT控制设计的问题,需要有新的能正确同时降低两种误差的管理控制方法。在文献中这个问题没有得到解决。
在这篇文章中,描述了三种量的控制,以同时减少外形和深度误差。首先调查对称交叉耦合(S-CC)控制,不幸的是它不能良好的同时减少误差。表现不佳的原因是同时减少两个误差的矛盾需求和缺乏信息交流的两个坐标面(X-Y和Y-Z),其中的误差相互补偿了。为解决这个问题,就要求各坐标轴间相互传送信息。这种观念导致两个新的控制类型：对称交叉耦合前馈(S-CC-FF)控制和非对称交叉耦合前馈(NS-CC-FF)控制。后,对系统稳定刃具可重组性的影响需要调查。
2机床特性和控制问题
在本节里我们说明的是RMT的经济优势,并制定了精确的代表性误差范围和深度误差。
A 机床特点
典型数控机床被建成通用机械。机械部分必须符合规划的利用特定机器方法的过程。这个设计过程中可能造成资金浪费: 由于数控机床首先设计的是机床的一部分，它必须建立在一般的灵活性,但这种灵活性不是全部用于加工特定部分。RMTS概念颠倒了设计的顺序：机床设计围绕着已知的部分零件库. 这造成了较复杂的设计过程中,虽然是柔性机床,但是一种机床包含了所有必要的功能性和柔性，这就需要一定的零件库。例如，RMT可能要包括减少轴的数量,降低成本和提高机器可靠性。因此,原则上,一个专用的RMT与一台类似的柔性数控机床价格差不多。RMT设计了一个概念性的例子,即一个与零件表面成45度的机床。如果用传统的数控机床加工倾斜表面的零件就需要4或5根轴。但是，这个例子在新型三轴非正交机床上只需要三根轴。然而,人们可能会认为自己的产品非正交45度机床是不经济的。因此,我们制定了三轴非正交角度机床,在重组期间机床Z 轴是可调节的。简单的调整机制不影响伺服控制,而且也没有经常移动轴的要求。在步骤15中在60-15度之间，RMT设计可重新设计成六个方向轴角位置。机床的主轴是X-轴()、Y-轴(驱动垂直方向的运动)和Z-轴(驱动倾斜方向的运动)。机床的二个极端位置成两根轴(-15 和60 度)。XYZ 机床轴包括一个非正交系统座标, 除了当轴是在一个水平位置的时候。二个正交辅助系统座标被使用描述机床，XSZ 和XYZ, S 是与零件表面平行的轴并且Z 是对X 和Ｙ轴垂直的轴。当刀具对表面是垂直的时候，机床被设计成在倾斜的表面加工。铣削时至少有二个轴参加切削运动。例如, 在倾斜的表面上加工时在S 轴方向要求机器驱动移动在正面Y 方向(向上) 并且在正面Z 方向(向下) 。当在RMT 的倾斜的表面上铣削非线性等高(如, 环行面)面时 , 我们也可能得到传统的误差。这是错误的工件表面测量(X- S平面 )与预定道路所需的工具。这误差在与工具的预定的需要的路径有关的工作件表面( X- S平面)上被测量。然而，在我们的机器中，我们同时得到附加的切削的误差。这误差在作为Y和Z路线中的结合的运动的结果削减的深度中被建立因为波动和因此我们把它称为“深度误差”。这所结合的运动被要求沿着倾斜的表面为了移动工具。数字4描述坐标的三个系统。 XYZ是桌子朝着X方向移动的坐标的机床非直角的系统，Y是沿着列运动，而Z朝着主轴和切削的工具的方向。XSZ是S是工作件的倾斜的表面的方向的坐标的一个辅助的直角的系统，这对工具路线是垂直的。 XYZ是另一个Z水平的坐标的辅助的直角的系统。
B 形状和深度误差
为了克服结合的误差，我们设计一个特殊的交叉耦合的控制。在现在的论文中，
我们愿意解释一些控制设计的方面。这运动的3轴的一个新的交叉耦合的控制的设计把洞察力给外部干扰下的系统行为。
形状误差：形状误差在许多报文中被描述了。被一个形状误差被定义为的一个即时的圆接近的一条一般的非线性曲线由Lo [ 15 ]给。数字5a显示形状和“彻底”误差。数字5b显示一个弯曲的形状误差。在RMT机器中的形状误差方程由于在30°和105°,之间变化Cry的特异性不需要考虑。
深度误差：误差对深度是典型的是我们的非直角的机器所特有的。为了切削一个预定的深度的工作件，必须被控制Y和Z路线的结合的运动。由于伺服机构驱动因为关于每一路线的外部干扰的位置误差误差深度被产生。我这误差可能在相当大的程度上影响表面结束的质量。误差在数字5c中深度被描述了。方程( 2 )描述Y和Z方向中的误差组成部分之间的线性的关系。理解这误差是重要，不仅记时依赖也依赖于机器再可重组角度的位置。对于每一主轴路线定位的角度，控制将在方程( 2 )中应用Czy的不同的价值。注意到Y路线Ey的位置误差在两Eqs上出现是重要(1)和( 2 )。这深度意味着严紧连接形状误差和误差。RMT控制应该有效地减少两个误差。
3控制设计
在传统的直角的CNC机器中，交叉耦合的控制策略有效地减少预定的工具路径和实际的工具路径之间的误差。在两路线形状系统中，X路线伺服传动装置收到两种输入：从从交叉耦合的控制减少减少rx (形状误差)的X组成部分的一X路线伺服机构控制的一传统的输入前(沿着X方向)的轴的位置误差和另一个输入。同样地，Y路线植物收到两种输入。每一路线的附加的输入用来朝着被代表的正常的方向减少形状误差图5b中的r。
本文的目标是为了形状和深度误差建议一个适合的交叉耦合的控制策略。三个控制被检查：一个对称的交叉耦合( S-CC )的控制，的对称的交叉耦合的控制附加向前馈 ( S-CC-FF )，和带有( NS-CC-FF )的一个非对称的交叉耦合的控制。
a 控制构造
三个控制的详尽的结构在基本的结构是有两个标准的交叉耦合( CC )的控制图6.中被说明了，一个个由于XY-辅助系统中的形状误差获得Gr和其它深度YZ-辅助系统的误差获得Gz。段4b包括关于Gr和Gz的价值的一次讨论。深度交叉耦合控制作为形状交叉耦合的控制有同样基本的控制结构。此外，一个前馈的期间可能被用来告知Z路线关于关于被输入的附加的Y路线之事宜由形状造成交叉耦合的控制。知道这信息提前，为了减少误差Z路线能弥补Y路线的运动深度。三个所提出的控制中的区别是： (a)一个前馈的期间( S -CC控制，Kff 块不存在)存在或者缺乏， ( b )朝着控制的误差( NS-CC-FF控制，Czy是零)的方向的一种区别。如果前馈的期间存在，数字6的Kff能被表达如下追踪误差评价获得，Crx，Cry，Czy，Czz被提交方程( 1 )和( 2 )。对称的交叉耦合( S-CC )的控制使用X和Y路线之间的形状交叉耦合的控制和在Y 和Z路线之间深度交叉耦合控制。当深度交叉耦合时，形状交叉耦合的控制通过连接X和Y路线运动减少形状误差控制通过连接Y和Z路线运动深度补偿误差。Y路线从每一个交叉耦合的控制收到一种输出； Ury和Uzy。当可能与彼此有矛盾时在以前的段，Ury和Uzy中简要地解释，而导致的控制行动不深度一定减少两形状和误差。这是S-CC控制的主要的弊端和它将在稳定段中更进一步被调查。
对称的交叉耦合的前馈 ( S -CC-FF )的控制有与S-CC控制同样的结构，但是包括一个附加的前馈的期间。这前馈的期间给关于关于Y路线的运动的Z路线信息。换句话说，当从形状交叉耦合的控制的一种输出被运用于Y路线时，这附加的输入被输送到Z路线从那附加的输入到Y路线深度为了减少误差。即使S-CC-FF控制通过增加一个前馈的期间改进系统的性能，交叉耦合的控制之间
的冲突仍然存在。再一次，这特色将在稳定段中更详细地被讨论。
这是介绍下一个控制的动机。非对称的交叉耦合的前馈 ( NS-CC-FF )的控制被建议在交叉耦合的控制之间连接。即使误差深度依赖于Y和Z路线的性能，这误差是与Z路线运动总平行的。使用这特色在其中来深度减少我们把控制改变成为控制移动仅仅Z路线的一个主动( Y ) 从动( Z )操作误差。即，连接交叉耦合控制深度交叉耦合的形状和控制在NS-CC-FF控制中被移去。因此，Y路线伺服机构驱动从交叉耦合的控制收到仅仅一种输出。然后这控制将被显示时有最好的性能。
附录A Lathe fixture design and analysis Ma Feiyue (School of Mechanical Engineering, Hefei, Anhui Hefei 230022, China) Abstract: From the start the main types of lathe fixture, fixture on the flower disc and angle iron clamp lathe was introduced, and on the basis of analysis of a lathe fixture design points. Keywords: lathe fixture; design; points Lathe for machining parts on the rotating surface, such as the outer cylinder, inner cylinder and so on. Parts in the processing, the fixture can be installed in the lathe with rotary machine with main primary uranium movement. However, in order to expand the use of lathe, the work piece can also be installed in the lathe of the pallet, tool mounted on the spindle. THE MAIN TYPES OF LATHE FIXTURE Installed on the lathe spindle on the lathe fixture
外文资料 The aggregate machine-tool CAD system development and research Abstract aggregate machine-tool CAD is in Window 95/98, Wndows under the NT4.0 environment, designs personnel's special-purpose CAD system with VC5.0 and the AutoCAD R14 ADS/ARX technology development face the aggregate machine-tool.This software technological advance, performance reliable, function strong, convenient practical, has provided the modernized design tool for our country aggregate machine-tool profession. Key word: Aggregate machine-tool CAD jig CAD multi-axle-box CAD 1 uses the aggregate machine-tool CAD technology imperative The aggregate machine-tool is with according to serialized, the standardized design general part and the special purpose machine which composes according to the work piece shape and the processing technological requirement design special-purpose part, belongs to the disposable design, the disposable manufacture piecework product.Therefore, the design quantity is big, the design work is complex.In the
Lathes Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up
毕业论文（设计） 外文翻译 题目：机械加工介绍
机械加工介绍 1.车床 车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。车削很少在其他种类的机床上进行，而且任何一种其他机床都不能像车床那样方便地进行车削加工。由于车床还可以用来钻孔和铰孔，车床的多功能性可以使工件在一次安装中完成几种加工。因此，在生产中使用的各种车床比任何其他种类的机床都多。 车床的基本部件有：床身、主轴箱组件、尾座组件、溜板组件、丝杠和光杠。 床身是车床的基础件。它能常是由经过充分正火或时效处理的灰铸铁或者球墨铁制成。它是一个坚固的刚性框架，所有其他基本部件都安装在床身上。通常在床身上有内外两组平行的导轨。有些制造厂对全部四条导轨都采用导轨尖朝上的三角形导轨（即山形导轨），而有的制造厂则在一组中或者两组中都采用一个三角形导轨和一个矩形导轨。导轨要经过精密加工以保证其直线度精度。为了抵抗磨损和擦伤，大多数现代机床的导轨是经过表面淬硬的，但是在操作时还应该小心，以避免损伤导轨。导轨上的任何误差，常常意味着整个机床的精度遭到破坏。 主轴箱安装在内侧导轨的固定位置上，一般在床身的左端。它提供动力，并可使工件在各种速度下回转。它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮(类似于卡车变速箱)所组成。通过变速齿轮，主轴可以在许多种转速下旋转。大多数车床有8~12种转速，一般按等比级数排列。而且在现代机床上只需扳动2~4个手柄，就能得到全部转速。一种正在不断增长的趋势是通过电气的或者机械的装置进行无级变速。 由于机床的精度在很大程度上取决于主轴，因此，主轴的结构尺寸较大，通常安装在预紧后的重型圆锥滚子轴承或球轴承中。主轴中有一个贯穿全长的通孔，长棒料可以通过该孔送料。主轴孔的大小是车床的一个重要尺寸，因此当工件必须通过主轴孔供料时，它确定了能够加工的棒料毛坯的最大尺寸。 尾座组件主要由三部分组成。底板与床身的内侧导轨配合，并可以在导轨上作纵向移动。底板上有一个可以使整个尾座组件夹紧在任意位置上的装置。尾座体安装在底板上，可以沿某种类型的键槽在底板上横向移动，使尾座能与主轴箱中的主轴对正。尾座的第三个组成部分是尾座套筒。它是一个直径通常大约在51~76mm之间的钢制空心圆柱体。
The Aggregate Machine-tool The Aggregate Machine-tool is based on the workpiece needs, based on a large number of common components, combined with a semi-automatic or automatic machine with a small number of dedicated special components and process according to the workpiece shape and design of special parts and fixtures, composed. Combination machine is generally a combination of the base, slide, fixture, power boxes, multi-axle, tools, etc. From. Combination machine has the following advantages: (1) is mainly used for prism parts and other miscellaneous pieces of perforated surface processing. (2) high productivity. Because the process of concentration, can be multi-faceted, multi-site, multi-axis, multi-tool simultaneous machining. (3) precision and stability. Because the process is fixed, the choice of a mature generic parts, precision fixtures and automatic working cycle to ensure consistent processing accuracy. (4) the development cycle is short, easy to design, manufacture and maintenance, and low cost. Because GM, serialization, high degree of standardization, common parts can be pre-manufactured or mass organizations outsourcing. (5) a high degree of automation, low labor intensity. (6) flexible configuration. Because the structure is a cross-piece, combination. In accordance with the workpiece or process requirements, with plenty of common parts and a few special components consisting of various types of flexible combination of machine tools and automatic lines; tools to facilitate modification: the product or process changes, the general also common components can be reused. Combination of box-type drilling generally used for processing or special shape parts. During machining, the workpiece is generally not rotate, the rotational motion of the tool relative to the workpiece and tool feed movement to achieve drilling, reaming, countersinking, reaming, boring and other processing. Some combination of turning head clamp the workpiece using the machine to make the rotation, the tool for the feed motion, but also on some of the rotating parts (such as the flywheel, the automobile axle shaft, etc.) of cylindrical and face processing. Generally use a combination of multi-axis machine tools, multi-tool, multi-process, multi-faceted or multi-station machining methods simultaneously, productivity increased many times more than generic tools. Since the common components have been standardized and serialized, so can be flexibly configured according to need, you can shorten the design and manufacturing cycle. Multi-axle combination is the core components of general machine tools. It is the choice of generic parts, is designed according to special requirements, in combination machine design process, is one component of a larger workload. It is based on the number and location of the machining process diagram and schematic design combination machine workpiece determined by the hole, cutting the amount of power transmission components and the design of each spindle spindle type movement. Multi-axle power from a common power box, together with the power box installed on the feed slide, to be completed by drilling, reaming and other machining processes. The parts to be processed according to the size of multi-axle box combination machine tool design, based on an original drawing multi-axle diagram, determine the range of design data,
毕业设计(论文)外文资料翻译 系部： 专业： 姓名： 学号： 外文出处：English For Electromechanical (用外文写) Engineering 附件：1.外文资料翻译译文；2.外文原文。 指导教师评语： 此翻译文章简单介绍了各机床的加工原理，并详细介绍了各机床的构造，并对方各机床的加工方法法进行了详细的描述， 翻译用词比较准确，文笔也较为通顺，为在以后工作中接触英 文资料打下了基础。 签名： 年月日注：请将该封面与附件装订成册。
附件1：外文资料翻译译文 机床 机床是用于切削金属的机器。工业上使用的机床要数车床、钻床和铣床最为重要。其它类型的金属切削机床在金属切削加工方面不及这三种机床应用广泛。 车床通常被称为所有类型机床的始祖。为了进行车削，当工件旋转经过刀具时，车床用一把单刃刀具切除金属。用车削可以加工各种圆柱型的工件，如：轴、齿轮坯、皮带轮和丝杠轴。镗削加工可以用来扩大和精加工定位精度很高的孔。 钻削是由旋转的钻头完成的。大多数金属的钻削由麻花钻来完成。用来进行钻削加工的机床称为钻床。铰孔和攻螺纹也归类为钻削过程。铰孔是从已经钻好的孔上再切除少量的金属。 攻螺纹是在内孔上加工出螺纹，以使螺钉或螺栓旋进孔内。 铣削由旋转的、多切削刃的铣刀来完成。铣刀有多种类型和尺寸。有些铣刀只有两个切削刃，而有些则有多达三十或更多的切削刃。铣刀根据使用的刀具不同能加工平面、斜面、沟槽、齿轮轮齿和其它外形轮廓。 牛头刨床和龙门刨床用单刃刀具来加工平面。用牛头刨床进行加工时，刀具在机床上往复运动，而工件朝向刀具自动进给。在用龙门刨床进行加工时，工件安装在工作台上，工作台往复经过刀具而切除金属。工作台每完成一个行程刀具自动向工件进给一个小的进给量。 磨削利用磨粒来完成切削工作。根据加工要求，磨削可分为精密磨削和非精密磨削。精密磨削用于公差小和非常光洁的表面，非精密磨削用于在精度要求不高的地方切除多余的金属。 车床 车床是用来从圆形工件表面切除金属的机床，工件安装在车床的两个顶尖之间，并绕顶尖轴线旋转。车削工件时，车刀沿着工件的旋转轴线平行移动或与工件的旋转轴线成一斜角移动，将工件表面的金属切除。车刀的这种位移称为进给。车
Int J Adv Manuf Technol (2006) 29: 178–183 DOI 10.1007/s00170-004-2493-9
ORIGINAL ARTICLE
Ferda C. C ? etinkaya
Unit sized transfer batch scheduling in an automated two-machine ?ow-line cell with one transport agent
Received: 26 July 2004 / Accepted: 22 November 2004 / Published online: 16 November 2005 ? Springer-Verlag London Limited 2005 Abstract The process of splitting a job lot comprised of several identical units into transfer batches (some portion of the lot), and permitting the transfer of processed transfer batches to downstream machines, allows the operations of a job lot to be overlapped. The essence of this idea is to increase the movement of work in the manufacturing environment. In this paper, the scheduling of multiple job lots with unit sized transfer batches is studied for a two-machine ?ow-line cell in which a single transport agent picks a completed unit from the ?rst machine, delivers it to the second machine, and returns to the ?rst machine. A completed unit on the ?rst machine blocks the machine if the transport agent is in transit. We examine this problem for both unit dependent and independent setups on each machine, and propose an optimal solution procedure similar to Johnson’s rule for solving the basic two-machine ?owshop scheduling problem. Keywords Automated guided vehicle · Lot streaming · Scheduling · Sequencing · Transfer batches entire lot to ?nish its processing on the current machine, while downstream machines may be idle. It should be obvious that processing the entire lot as a single object can lead to large workin-process inventories between the machines, and to an increase in the maximum completion time (makespan), which is the total elapsed time to complete the processing of all job lots. However, the splitting of an entire lot into transfer batches to be moved to downstream machines permits the overlapping of different operations on the same product while work proceeds, to complete the lot on the upstream machine. There are many ways to split a lot: transfer batches may be equal or unequal, with the number of splits ranging from one to the number of units in the job lot. For instance, consider a job lot consisting of 100 identical items to be processed in a three-stage manufacturing environment in which the ?ow of its operations is unidirectional from stage 1 through stage 3. Assume that the unit processing time at stages 1, 2, and 3 are 1, 3, 2 min, respectively. If we do not allow transfer batches, the throughput time is (100)(1+3+2) = 600 min (see Fig. 1a). However, if we create two equal sized transfer batches through all stages, the throughput time decreases to 450 min, a reduction of 25% (see Fig. 1b). It is clear that the throughput time decreases as the number of transfer batches increases. Flowshop problems have been studied extensively and reported in the literature without explicitly considering transfer batches. Johnson [1], in his pioneering work, proposed a polynomial time algorithm for determining the optimal makespan when several jobs are processed on a two-machine (two-stage) ?owshop with unlimited buffer. With three or more machines, the problem has been proven to be NP-hard (Garey et al. [2]). Besides the extension of this problem to the m -stage ?owshop problem, optimal solutions to some variations of the basic two-stage problem have been suggested. Mitten [3] considered arbitrary time lags, and optimal scheduling with setup times separated from processing was developed by Yoshida and Hitomi [4]. Separation of the setup, processing and removal times for each job on each machine was considered by Sule and Huang [5]. On the other hand, ?owshop scheduling problems with transfer batches have been examined by various researchers. Vickson
1 Introduction
Most classical shop scheduling models disregard the fact that products are often produced in lots, each lot (process batch) consisting of identical parts (items) to be produced. The size of a job lot (i.e., the number of items it consists of) typically ranges from a few items to several hundred. In any case, job lots are assumed to be indivisible single entities, although an entire job lot consists of many identical items. That is, partial transfer of completed items in a lot between machines on the processing routing of the job lot is impossible. But it is quite unreasonable to wait for the
F.C. ?etinkaya (u) Department of Industrial Engineering, Eastern Mediterranean University, Gazimagusa-T.R.N.C., Mersin Turkey E-mail: ferda.cetinkaya@https://www.doczj.com/doc/e04691070.html,.tr Tel.: +90-392-6301052 Fax: +90-392-3654029
机床加工外文翻译参考文献(文档含中英文对照即英文原文和中文翻译) 基本加工工序和切削技术 基本加工的操作 机床是从早期的埃及人的脚踏动力车和约翰·威尔金森的镗床发展而来的。它们为工件和刀具提供刚性支撑并可以精确控制它们的相对位置和相对速度。基本上讲，金属切削是指一个磨尖的锲形工具从有韧性的工件表面上去除一条很窄的金属。切屑是被废弃的产品，与其它工件相比切屑较短，但对于未切削部分的厚度有一定的增加。工件表面的几何形状取决于刀具的形状以及加工操作过程中刀具的路径。 大多数加工工序产生不同几何形状的零件。如果一个粗糙的工件在中心轴上转动并且刀具平行于旋转中心切入工件表面，一个旋转表面就产生了，这种操作称为车削。如果一个空心的管子以同样的方式在内表面加工，这种操作称为镗孔。当均匀地改变直径时便产生了一个圆锥形的外表面，这称为锥度车削。如果刀具接触点以改变半径的方式运动，那么一个外轮廓像球的工件便产生了；或者如果工件足够的短并且支撑是十分刚硬的，那么成型刀具相对于旋转轴正常进给的一个外表面便可产生，短锥形或圆柱形的表面也可形成。
平坦的表面是经常需要的，它们可以由刀具接触点相对于旋转轴的径向车削产生。在刨削时对于较大的工件更容易将刀具固定并将工件置于刀具下面。刀具可以往复地进给。成形面可以通过成型刀具加工产生。 多刃刀具也能使用。使用双刃槽钻钻深度是钻孔直径5-10倍的孔。不管是钻头旋转还是工件旋转，切削刃与工件之间的相对运动是一个重要因数。在铣削时一个带有许多切削刃的旋转刀具与工件接触，工件相对刀具慢慢运动。平的或成形面根据刀具的几何形状和进给方式可能产生。可以产生横向或纵向轴旋转并且可以在任何三个坐标方向上进给。 基本机床 机床通过从塑性材料上去除屑片来产生出具有特别几何形状和精确尺寸的零件。后者是废弃物，是由塑性材料如钢的长而不断的带状物变化而来，从处理的角度来看，那是没有用处的。很容易处理不好由铸铁产生的破裂的屑片。机床执行五种基本的去除金属的过程：车削，刨削，钻孔，铣削。所有其他的去除金属的过程都是由这五个基本程序修改而来的，举例来说，镗孔是内部车削；铰孔，攻丝和扩孔是进一步加工钻过的孔；齿轮加工是基于铣削操作的。抛光和打磨是磨削和去除磨料工序的变形。因此，只有四种基本类型的机床，使用特别可控制几何形状的切削工具1.车床，2.钻床，3.铣床，4.磨床。磨削过程形成了屑片，但磨粒的几何形状是不可控制的。 通过各种加工工序去除材料的数量和速度是巨大的，正如在大型车削加工，或者是极小的如研磨和超精密加工中只有面的高点被除掉。一台机床履行三大职能：1.它支撑工件或夹具和刀具2.它为工件和刀具提供相对运动3.在每一种情况下提供一系列的进给量和一般可达4-32种的速度选择。 加工速度和进给 速度，进给量和切削深度是经济加工的三大变量。其他的量数是攻丝和刀具材料，冷却剂和刀具的几何形状，去除金属的速度和所需要的功率依赖于这些变量。 切削深度，进给量和切削速度是任何一个金属加工工序中必须建立的机械参量。它们都影响去除金属的力，功率和速度。切削速度可以定义为在旋转一周时
TRANSFER AND UNIT MACHINE While the specific intention and application for transfer and unit machine vary from one machine type to another, all forms of transfer and unit machine have common benefits. Here are but a few of the more important benefits offered by TRANSFER AND UNIT MACHINE equipment. The first benefit offered by all forms of transfer and unit machine is improved automation. The operator intervention related to producing workpieces can be reduced or eliminated. Many transfer and unit machine can run unattended during their entire machining cycle, freeing the operator to do other tasks. This gives the transfer and unit machine user several side benefits including reduced operator fatigue, fewer mistakes caused by human error, and consistent and predictable machining time for each workpiece. Since the machine will be running under program control, the skill level required of the transfer and unit machine operator (related to basic machining practice) is also reduced as compared to a machinist producing workpieces with conventional machine tools. The second major benefit of transfer and unit machine technology is consistent and accurate workpieces. Today's transfer and unit machines boast almost unbelievable accuracy and repeatability specifications. This means that once a program is verified, two, ten, or one thousand identical workpieces can be easily produced with precision and consistency. rd benefit offered by most forms of transfer and unit machine tools is flexibility. Since these machines are run from programs, running a different workpiece is almost as easy as loading a different program. Once a program has been verified and executed for one production run, it can be easily recalled the next time the workpiece is to be run. This leads to yet another benefit, fast change over. Since these machines are very easy to set up and run, and since programs can be easily loaded, they allow very short setup time. This is imperative with today's just-in-time (JIT) product requirements.