Research And Development Of Cutting Robot Control System Based On EtherCAT

With the rapid development of industrial robot technology,industrial robot has been widely used in water cutting,laser cutting and other cutting processing fields.The development of special cutting robot control system meets the market demand.With the rapid development of the field bus technology,the real-time and openness of the traditional robot control system can not meet the requirements of high-precision and intelligent robot,so the development of robot control system using PC and EtherCAT field bus technology has become a trend in the field of industrial control.Based on EtherCAT real-time Ethernet bus technology,a set of special six axis serial robot control system is developed in PC and Beckhoff embedded PC hardware platform,which can directly cut according to five axis cutting NC code.The system has high real-time performance,strong stability and good openness.According to Craig's principle,the D-H model of Qianjiang RH6 six axis series robot is established,and the forward and inverse kinematics algorithm of cutting robot is obtained.The forward and inverse kinematics algorithm of cutting robot is simulated and verified by MATLAB Robotic Toolbox library in MATLAB.A direct robot inverse solution selection algorithm with minimum angle change rate optimization is proposed,which can directly determine the only optimal solution among 8 groups of theoretical robot inverse solutions without cycle iteration.The algorithm has high efficiency and good real-time performance.The control system development solution of EtherCAT bus cutting robot,which is separated from the upper computer and the lower computer,is proposed.The upper computer is based on Windows 7/10 operating system.On the common PC,the non real-time function modules such as robot human-computer interface design,NC file analysis,status monitoring,OpenGL dynamic simulation,ADS communication are completed through MFC development.Based on TwinCAT3 PLC software development platform,ST programming language,COE protocol,PP and CSP position control mode,the lower computer independently developed and completed real-time functional modules such as robot forward and inverse solution algorithm module,robot five axis interpolation algorithm module,automatic cutting and processing algorithm module,avoiding TwinCAT3 The high software license cost brought by the standard motion control libraries such as NC and CNC.The hardware platform of the control system of the EtherCAT field bus cutting robot is built.The linear topology structure is adopted.The main station is BECKHOFF embedded PC,and six groups of Panasonic MINAS-A6 B series AC servo drivers are slave stations.The ADS synchronous communication is realized by establishing the Self ads communication class between the upper computer and the lower computer;the EtherCAT bus communication with a communication period of 1ms is realized between the embedded PC and the servo driver by self configuring the PDO process data object mapping.The experiment of robot cutting is designed and realized.The experiment results meet the expected motion control requirements.It lays a foundation for the design and development of trajectory planning algorithm,speed forward-looking algorithm and dynamic control algorithm of the subsequent cutting robot control system.