自动化专业本科生毕业设计 外文翻译-数控钻床控制系统设计

1、 密 级分类号编 号成 绩本科生毕业设计 (论文)外 文 翻 译原 文 标 题CNC DRILLING MACHINE CONTROL SYSTEM DESIGN译 文 标 题数控钻床控制系统设计作者所在系别电子工程系作者所在专业自动化作者所在班级作 者 姓 名作 者 学 号指导教师姓名指导教师职称完 成 时 间2021年12月07日北华航天工业学院教务处制译文标题伺服系统的设计3-Axis数控钻床基于xPC目标原文标题Design of Servo System for 3-Axis CNC Drilling Machine Based on xPC Target作 者Butler Jero

2、me译 名杰罗姆巴特勒等国 籍美国原文出处Atomation Professional English CauseAbstract As special equipments, the CNC drilling machines require servo systems specially designed. So there is a substantial waste of time and energy. In order to solve this problem, a design proposal for the servo system of 3-axis CNC drilli

3、ng machine based on xPC Target is presented in this paper. Taking a CNC drilling machine model as the experiment platform, the block diagram of the servo system was designed using SIMULNK tools, and compiled into a real time system by VC complier, which could run on X86 computer. Rapid developing of

4、 a servo system for 3-axis CNC drilling machine is easily implemented by this proposal. The experimental results demonstrate that the feed system of the drilling machine model could carry out a quick precisionpositioning. Key words-servo systems; drilling machines; xPC Target;I. INTRODUCTIONThe CNC

5、drilling machine is mainly for drilling holes with numerical control. The most products are special Figure 1. The control system structure of 3-axis CNC drilling machineequipments, which are widely used in hole processing technology for the PCB and large porous tube sheet parts.1 And, these products

6、 most are special equipments, can be classified as CNC vertical drill, drilling center, CNC PCB drill, CNC deep-hole drill and other large CNC drilling machine.2 It is applicable to machining the parts with lots of precise holes in procedures of drilling, spreading, weaning and threading. Especially

7、, its important to improve the machining accuracy and efficiency that choose a special CNC drilling machine to work the PCB and large porous tube sheet. While, the design of servo system is the most complex in the process of designing a special CNC drilling, and require plenty of time to program and

8、 debug. So, it not only consumes the valuable intellectual resources, but constrains to market the product timely. XPC Target is a tool set based on Matlab/SIMULINK that is provided by MathsWorks. It has a wealth of I/O device modules which support the majority of integrated circuit boards.3 And, xP

9、C Target introduced a host-target technical means, one PC as host computer, and another industrial computer as target computer, two computers connected with network cards and communicate through TCP/IP protocol. The systems by xPC Target can run onX86 computer real-time. It achieves simulation on bo

10、ard and rapid prototyping of control systems. The CNC technology lab for scientific research in Guangdong province developed a 3-axis CNC drilling machine model which is based on the product manufactured by Shenzhen Open Technology Corporation. Using the drilling machine model as test platform, desi

11、gned the special servo system based on XPC Target. II. SERVO CONTROL SYSTEM STRUCTURE OF THE 3-AXIS CNC DRILLING MACHINE The control system of the 3-axis CNC drilling machineis a two-level computer control structure: the host computeris a personal computer, and carries out drawings,commands, communi

12、cations etc. the lower computer is anembedded computer of PC/104, as the core unit of servocontrol system in the drilling machine.The host computer communicates the data of commands and motion states with the embedded computer of PC/104 by RS232, As shown in Fig.1. And, apply the Modbus communicatio

13、n protocol to keep the data mutually transmitted exactly. In this system, ADT652 expansion card according with PC/104 bus is used as the I/O interface of the system. Using the software of SIMULINK, designed servo control system of 3-axis CNC drilling machine based on XPC Target. And, the software of

14、 the system was downloaded to the PC/104 and real-time operated ascompiled and debugged successfully. After complicated computing, the PC/104 modulates the results into a corresponding PWM signal that is exported to the motor drive circuit through ADT652 board. Then, the motor driving the correspond

15、ing axis rotates at a definite speed under control. At the other side, a incremental rotational photoelectric encoder was fixed on the servo motor of the relevant feeding mechanism to obtain its position，which is fed back to the PC/104 by the I/O port of ADT652. While, the motional speed of the spin

16、dle servo motor is obtained by speed senor, and is fed back to the PC/104 by the ADC channel of ADT652.III. ESTABLISH THE SERVO CONTROL SYSTEMIn general, the servo control of CNC drilling machines feeding mechanism is point-to-point control. And, thefeeding rate of X, Y-axis could obviously affects

17、promoting the production efficiency, but the Z-axis feeding rate would not archive the effect for the factors of the drill and the processing materials. On this platform, a DC motor is used as the power set of the feeding mechanism. Compared with AC motor control, DC motors drive circuit is more sim

18、ple and reliable. Moreover, the speed adjusting accuracy and dynamic response characteristics of the DC motor are more ideal with a greater speed range and higher speed adjusting accuracy.4 So, it can be satisfied with the experiment requirement better. As the value of inductance (L) in the armature

19、 circuit of DC motor is very low, it can be ignored in the mathematical model of the servo systems. Then, taking the armature voltage (Ua(s) as the input value and the motor speed (s) as the output value, the mathematical model of armature-control DC motor is established, and the model can be regard

20、ed as a 1st-order system. The transfer functionof the model is: Taking the angle of the motor (s) as the input valueand the linear displacement of the workbench (Xo(s) as the output value, the mathematical model of the working platform can be also simplified as a 2nd-order system. Its transfer funct

21、ion is:With comprehensive consideration on the mathematical model of the DC motor and the working platform, the servo system can be simplified as a 2nd-order system model. Its transfer function is:The servo control system of the X-axis feeding system for the CNC Drilling Machine is presented in this

22、 paper.And the other feeding systems are not described in detail for being similar with the X-axis.A. Mathematics modelingOn the 3-axis CNC drilling machine model, a Maxon motor F2260 is fixed as the power set of the X-axis feedingmechanism. And the rotation of motor can be converted into the linear

23、 motion of the workbench through the mechanism of lead screw. We can create the transfer function with the characters about the motor and workbench which is shown in the table I. The transfer function of X-axis servo system is obtained by the above parameters of Motor and workbench: B. PID controlle

24、r designIn this paper, a PID compensator is designed to adjust the motion of the servo system according to themathematical model above. And its parameters are set withthe experiential formula of Ziegler-Nichols5 by MATLAB software. The formula is: In the formula, the Km is the value of proportional

25、gain as the time systems begin to shock, and the m is theoscillation frequency at this point. Firstly, the mathematical model of the controlled object is converted into a discrete model using zero-order holder. Then, use the commands of rlocus and rlocfind to obtain the oscillation gain Km and the o

26、scillation frequencym at the critical point . Finally, the parameters of the PIDcompensator can be obtained by the formula (5):The step responding curves about the pre-tuning and after-tuning are shown in Fig.2. We can find that theoscillation and overshoot of the systems step responding was elimina

27、ted for the adjustment of the PID compensator, and the system can get to a steady-state in 1.5 seconds. In addition, an integral weakening technique is introduced in the PID compensator to enhance the stability of the servo systems. the technique is that when thedeviation value (ei) between the feed

28、back value and the aim parameter of servo system is greater than a stipulated threshold, the section of integral doesnt work. So the integral value will not be too large. Only when the deviation value is small, It works to eliminate the static error of system. Its PID algorithm is presented as posit

29、ion type: The outcome of simulation indicates vividly that the PID compensator fulfills the requirements very much of quick precision positioning in the point-to-point control of CNC drilling machine.C. Design servo system base on xPC targetThere are a set of xPC target tools in the SIMULINK softwar

30、e, such as RS232 communication tool, timing tool,I/O interface tool etc. these can be used in to establish control block diagram of the servo system.6According to the servo system models which be described as the formula (4), using MATLAB/SIMULINKwe can easily establish the simulation models for the

31、 3-axis CNC drilling machine. The control block diagram of the X-axis servo system is shown in fig.3. This is only a non-real-time, off-line simulation studies.7 But, when the system is running on the actual hardware in which integration of in-the-loop testing and debugging can beachieved.On the har

32、dware, an ADT652 based on the PC/104 bus is used as the data acquisition card. And, the PORTA ofADT652 reads pulses of the incremental rotational photoelectric encoder in real-time, and sends it to PC/104which would converts it into a angle value as feedback of the system.8 Here, the PORTAs address

33、is 0 x308, andthe base address of ADT652 is set as 0 x300 through jumper. Then, the deviation value (ei) between the feedback value and the aim parameter of servo system is involved in the operation of the PID compensator designed well. The skill of limiting integration is use in the PID compensator

34、. At last, a regulating variable comes to output. the regulating variable is converted to a PWM signal which is sent to the motor drive circuit through the PORTB of ADT652, which address is 0 x309. So, the speed control loop for the servo motor of X-axis is created. With MATLAB/ SIMULINK running on

35、the host computer, and the development environment9 of Real-TimeWorkshop, xPC Target and VC6.0 compiler set well, the block diagram of the servo system designed well could be converted into an application which would be download to the target computer (PC/104) through TCP/IP protocol. Then, the CNC

36、system is created and could run on the 3-axis CNC drilling machine model in real-time.The servo control block diagrams of the other feeding systems for the three-axis CNC drilling machine modelare similar with the X axis, so they are no longer detaileddescribed hereThe three-axis CNC drilling machin

37、e model was used as the experimental platform which dimension is 200mm150mm50mm corresponding to its XYZ axis. And the servo system is established and regulated according to the Fig.1. Then, the servo control system block diagram was complied into an application by the VC compiler in a MatlabRTW env

38、ironment properly set up. At last, an experiment was carried out to detect the performance of the system designed here on the drilling machine model, taking a personal computer as the host computer and the PC/104 as the target computer in which the application generated is running in real-time.the c

39、oordinate point of the target is situated at 100000 m,70000m,30000m. And the host computer sent the coordinates and control commands to the lower computer. The workbench ran to the target point with the control of the CNC system. The actual position of the workbench was measured exactly by the grati

40、ng rules which were installed on the lathe guide rails. The measurement accuracy of the grating rule is 1(m).10 In each experiment, the workbench ran from the zero position to the same target described above. And, the experimental data on position by grating rules is shown in the table below. The ov

41、erall precision parameters of the drilling machine system can be drawn after analysis of the data in the table II: the positioning accuracy : 0.02(mm) the reorientation accuracy: 0.01(mm).Theoretically, the control accuracy could be achieved to 3(m), because an optical encoder with 500 lines isused

42、on the servo motor.But the actual error is greater than that. There are some reasons.1) The elastic deformation of workbench impacts.2) There is a measurement error on the grating rule.3) The error of screw assembly impacts4) The error of zero point impacts.V. CONCLUSIONThis paper presents a design

43、proposal for the servo control system of three-axis CNC drilling machine based onXPC Target. The development of the whole control system could be completed in a short time by this method. And, the experimental results demonstrate that the feeding system can run to the target position quickly and pre

44、cisely. This design scheme could be widely applied to develop the intelligent control systems for various special CNC drilling machines, and also be used to develop the control system for the equipment of automatic production line.REFERENCES1 YUEKANG Shan, CHANG Xu, QING Jiang, “Based-on computer vi

45、sion auto-aligning drilling machine for PCB, Proceedings of SPIE - The International Society for Optical Engineering, vol. 3558, 1998, pp. 74-80.2 Bateman, Andy, “Drilling machine project cuts through traditional design principles, Engineering Technology, vol. 8, no.9, November 2005, pp. 38-41.3 A.

46、Tahboub Karim, I. Albakri Mohammad, M. Arafeh Aziz, “Development of a flexible educational mechatronic system based on xPC target, DETC2007, vol. 4, 2021, pp. 209-217.4 H.P. Huang, Z.L. Wang, J.M. Zheng, “Development of a CNC system for multi-axis EDM and its realization, Key Engineering Materials,v

47、ol. 392-394, 2021, pp. 50-54.5 L.Z. Jiang, J. Yang, Z. Yang, “Design proposal for robot servo system based on MatlabRTW, Huanan Ligong Daxue Xuebao/Journal of South China University of Technology (Natural Science), vol. 36, no. 9, September 2021, pp. 136-139.6 M. Wang, C.L. Xiang, Y. Ma. “The data a

48、cquisition system based on xPC target environment, Journal of Test and Measurement Technology, vol. 18, 2004, no. 3, pp. 228-231.7 J.B. Chen, Z.J. Zhang, Y.J. Gao, L.H. Li, D.L. Xi, “The computer control experiment system for biological sewage treatment teaching based on xPC-target, 2006 Chinese Con

49、trol Conference Proceedings, 2007, pp. 1496-1499.8 Mraz Stephen, “Digital drive acts as an extension of the controller, Machine Design, vol. 77, no. 15, Aug 4, 2005, pp. 42-44.9 P.S. Shiakolas, S.R. Van Schenck, I. Frangeskou, “A real-time digital control environment based on MATLAB, xPC-target alon

50、g with amagnetic levitation device for neural network control law implementation and verification, American Society of Mechanical Engineers, Dynamic Systems and Control Division (Publication) DSC, vol. 72, no. 2, 2003, pp. 1293-1301.10 J. Liu, K. Butler Jerome, A. Evans Gary, K. DeFreez Richard, “Gr

51、ating theory for feedback and outcoupling of quantum well laser structures, Proceedings of SPIE - The International Society for Optical Engineering, vol. 2399, 1995, pp. 84-94. 介绍数控钻床主要为通过数字控制进行钻孔。很多产品都是特殊的工件,它们被广泛应用于PCB孔加工和大型多孔不见的加工。1这些产品大局部是特殊的设备,它们可分为数控立式钻、钻孔中心、数控PCB钻、数控深孔钻和其他大型数控钻床。2它适用于加工钻井、传播、

52、脱机和穿线等有很多精密孔的工件。特别是,要提高加工精度和效率,选择一个特别的数控钻床加工PCB及大型多孔管很重要。同时, 设计一个特殊的数控钻是设计的伺服系统中最复杂的设计过程,它需要足够的时间来方案和调试。因此,它不仅需要有丰富的知识资源,而且制约了市场的产品及时性。XPC目标是以Matlab / SIMULINK根底的一个工具, Matlab / SIMULINK是由MathsWorks提供的。它具有丰富的I / O设备模块支持大多数集成电路板。3一台计算机作为上位机(主机),另一种工业计算机作为目标电脑,两台计算机通过网卡连接，通过TCP / IP协议交流。这个系统能在X86 计算机的实

53、时系统中运行。它能对成型的控制系统进行快速仿真。数控技术实验室进行科学研究，开发了一种3-axis数控钻床模型,该模型是基于开放的高新技术公司制造的产品。利用钻孔机的测试平台模型,设计了基于XPC目标的特殊伺服系统。II。3-AXIS数控钻床的伺服控制系统结构3-axis数控钻床的图1。控制系统的体系结构3-axis数控钻床 人伺服系统设计方案的根底le control system控制系统包括两级计算机控制结构:主机一台，并落实图纸、指挥、通讯等，一个以PC / 104做为为核心的嵌入式计算机的钻孔机伺服控制系统。通过RS232,主机的命令与机器运动状态数据与PC / 104嵌入式进行沟通。

54、如图1。运用网络通信协议确保数据相互传播的正确性。在这个系统中, 根据PC / 104总线的ADT652扩充卡用来作为系统的I / O接口。利用SIMULINK仿真软件,设计以XPC目标为根底的3-axis数控钻床伺服控制系统。系统的软件被成功下载到PC / 104和实时操作编译和调试。在复杂的计算后,PC / 104调整输出为一个相应的PWM脉宽调制信号, 通过ADT652板被输出到电机驱动电路。然后, 控制电机驱动相应的轴在一定的旋转速度之下。在另一边,一个增量旋转光电编码器固定在伺服马达相关的进料机构以获得其位置,反应到PC / 104的ADT652 I / O端口。同时,通过测速器得到

55、伺服电机主轴的运动速度, 通过ADT652 的ADC通道反应到PC / 104。三。建立了伺服控制系统一般来说,伺服控制数控钻床的进料机构是点对点控制。而且X、Y轴进给率能明显影响生产效率,但z轴进给率不会因为钻头和加工材料因素而受影响。在该平台上,一个直流电机作为进料机构的动力装置。和交流电机控制相比，直流电机的驱动电路简单、可靠。此外,调速精度和动态响应特性的较为理想的直流电机速度调整的调速范围大,精度更高。4因此,它可以更能满足实验要求。电感(L)的值在直流电机电枢电路很低,它在伺服系统的数学模型可以被忽略。然后,以电枢电压(Ua(s)为输入值和电机转速(s)作为输出值的电枢控制直流电机

56、的数学模型就建立了,该模型可以被看作是一种1阶系统。所建立模型的传递函数是:以电机的角度(s)作为输入值，工作台线性位移 (Xo(s)作为输出值,工作平台的数学模型,也可以简化为2阶系统。其传递函数是：综合考虑直流电机的数学模型和工作平台、伺服系统可以简化为2阶系统模型。其传递函数是:x轴进料系统的数控钻床伺服控制系统已在本文提出。其他轴的给料系统类似于x轴这里就不再不详细描述。数学建模在3-axis数控钻床模型中,F2260电机是固定作为x轴动力的装置。旋转电机可以将工作台通过导螺杆转换成的直线运动。我们能通过显示在表中电机和工作台的参数写出传递函数。通过上述对运动的描述及工作台的参数得到伺

57、服系统x轴的传递函数:PID控制器设计b .本文设计了PID补偿调节伺服系统的运动,根据上述数学模型和它与公式的参数设定用MATLAB软件画出Ziegler-Nichols5。采用该公式:该公式中的Km值是系统伴随时间的比例增益,m是在这一点的振荡频率。首先,被控对象的数学模型转化为离散模型，然后,用rlocus 和 rlocfind命令在临界点获得震荡增益Km和震荡频率Wm。最后,PID补偿器参数通过求解公式(5)得到:这一步的校正后和校正前的响应曲线显示在图2。我们可以发现: 调整的PID补偿器可以消除系统阶跃响应的振动和超调,该系统可以到达一个稳态。此外,还介绍了整体弱化技术PID补偿器

58、来提高伺服系统的稳定性。这个技术是当偏差值(ei)之间的反应值和伺服系统的目的参数比规定阈值大、积分局部不起作用了。所以积分值不应太大。只有当偏差值小,它的作用是消除系统的稳态误差。它的PID算法如下:仿真结果明确说明,PID补偿器非常满足在点对点控制的数控钻床需求的快速精确定位。C设计基于c xPC目标的伺服系统的在SIMULINK仿真软件有一组xPC目标的工具 ,如RS232通讯工具,计时工具,I / O接口工具等等,这些可以用于建立伺服系统的控制框图。6根据公式(4)描述伺服系统模型,利用MATLAB / SIMULINK仿真我们可以很容易的建立3-axis数控钻床仿真模型。X轴伺服系统的控制框图显示在图3。这只是一