视觉定位装配机器人的运动控制系统设计

发布时间：2018-05-07 12:47

本文选题：可编程逻辑控制器 + 运动控制系统　；参考：《陕西科技大学》2017年硕士论文

【摘要】：在人工成本不断攀升的背景下,企业对自动化以及智能化产品的需求不断扩大,不同功能类型的机器人在企业中逐渐普及。作为工业领域最重要机种之一的装配机器人在企业生产过程中的运用越来越广泛,设计与开发也日趋成熟。然而,受到装配精度、价格以及智能化程度的影响,装配机器人很难被大众化中小型企业所接受,在很多装配车间,依然依靠大量的人工对产品进行装配。运动控制系统是装配机器人实现复杂装配技术的关键系统。本文以视觉定位装配机器人为研究对象,实用性为理念,控制精度为核心,实现精密装配为最终目标,开发一款经济、实用、智能的运动控制系统,实现在工件和装配点位姿随机的情况下,高精度、高效率地完成自动化装配的目的。(1)通过详细地分析装配工艺过程,明确装配机器人运动控制系统所要实现的功能。并以此为依据,完成各主要硬件的选型,并结合所选硬件和实际控制要求,完成运动控制系统的总体方案设计。上位机选用电脑,下位机选用PLC,上位机与PLC之间通过RS485串口通信;同时,PLC通过另一组485端口,以RS485总线的形式实现对四组伺服电机的控制。(2)根据视觉定位装配机器人的实际结构,利用第一杆件坐标系,建立运动学方程,求出关节变量表达式,并对逆解存在多解的情况进行分析,利用“最接近解”原则删选出最优解。利用带抛物线过渡的线性规划完成路径规划,并得到最终的速度和加速度表达式。(3)采用PR模式控制伺服驱动器,结合外围硬件特点和实际功能需求,分析PLC所需要的I/O点数和应具备的功能,完成PLC的选型及其I/O地址的分配,完成电气系统和气动系统的设计,组装好控制柜。并采用模块化的编程思想,利用梯形图完成PLC控制系统程序的设计,实现了PLC通过RS485总线、Modbus协议对四组伺服电机的精确控制。(4)在Visual Studio 2012开发环境下,利用MFC开发上位机系统和人机交互界面。采用C/C++高级语言,完成通信程序的编写,实现了电脑与PLC之间通过RS485串口的通信。同时,上位机对视觉系统提取到的位姿信息进行处理,软件实现对关节变量、速度和加速度的求解,统一单位后,通过RS485发送给PLC。PLC对接收到的数据进行解析处理,提取各轴运动的实际位移量和速度值。运动控制系统最终实现手动和自动两种控制模式。实际测试表明,PLC通过RS485总线能够实现对4组伺服电机的独立协调控制,并且该运动控制系统性能稳定,执行效率高,能满足工业现场高精度装配的要求,具有很强的实用性。
[Abstract]:Under the background of rising labor cost, the demand for automation and intelligent products is expanding, and robots of different functional types are becoming more and more popular in enterprises. As one of the most important kinds of machinery in industrial field, assembly robot is used more and more widely in the process of enterprise production, and the design and development are becoming more and more mature. However, due to the influence of assembly precision, price and intelligence, the assembly robot is difficult to be accepted by the popular small and medium-sized enterprises. In many assembly workshops, it still relies on a large number of manual assembly products. Motion control system is the key system for assembly robot to realize complex assembly technology. In this paper, an economical, practical and intelligent motion control system is developed, which takes the visual positioning assembly robot as the research object, the practicability as the concept, the control precision as the core, and the precision assembly as the final goal. The purpose of automatic assembly with high precision and high efficiency is realized under the condition of random position and pose of workpiece and assembly point. Through detailed analysis of assembly process, the function of motion control system of assembly robot is clarified. On the basis of this, the selection of main hardware is completed, and the overall scheme design of motion control system is completed by combining the selected hardware and actual control requirements. PC is used as host computer, PLC is used as lower computer, communication between host computer and PLC is via RS485 serial port, In the form of RS485 bus, the control of four groups of servomotors is realized. According to the actual structure of the visual positioning assembly robot, the kinematics equation is established by using the first bar coordinate system, and the expression of the joint variable is obtained. By analyzing the existence of multiple solutions in inverse solutions, the optimal solution is selected by using the principle of "nearest solution". The path planning is accomplished by linear programming with parabola transition, and the final expression of velocity and acceleration is obtained. The servo driver is controlled by PR mode, combined with the characteristics of peripheral hardware and the actual functional requirements. This paper analyzes the I / O points and functions required by PLC, completes the selection of PLC and the allocation of I / O address, completes the design of electrical and pneumatic systems, and assembles the control cabinets. The program of PLC control system is designed by using trapezoid diagram and modular programming idea. The precise control of four groups of servomotors by RS485 bus is realized by PLC in Visual Studio 2012 development environment. Using MFC to develop upper computer system and man-machine interface. Using C / C language, the communication program is written, and the communication between computer and PLC is realized through RS485 serial port. At the same time, the upper computer processes the position and pose information extracted from the visual system, and the software realizes the solution of the joint variables, velocity and acceleration. After unifying the unit, it sends the received data to PLC.PLC through RS485 to analyze and process the received data. The actual displacement and velocity of each axis are extracted. The motion control system finally realizes two control modes, manual and automatic. The actual test shows that the RS485 bus can realize the independent coordinated control of the four groups of servo motors, and the motion control system is stable in performance, high in execution efficiency, and can meet the requirements of high precision assembly in the industrial field. It has strong practicability.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TP242

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