摘要
以双相机引导机械手贴合系统为研究背景,研究了EtherCAT实时性对SCARA机器人运动轨迹精度的影响。对SCARA机器人的运动学进行建模,采用标准的D-H建模法,确定机器人的连杆参数,分析机器人的正运动学和逆运动学,并采用解析法求解运动学逆解。利用MATLAB中的机器人工具箱Robotics Toolbox,对机器人的运动学进行仿真分析,验证了运动学模型建立的正确性。分析了EtherCAT的实时性,通过EtherCAT的分布时钟同步机制,由抓包工具为以太网报文打上时间戳;采用wireshark抓包软件,分析数据传输过程中的抖动延时;采用示波器,测出同步误差,验证了EtherCAT的高同步性。采用七次多项式轨迹规划算法,在试验平台进行了轨迹精度的验证。验证结果表明:EtherCAT同步时,其速度给定与反馈的偏差小、波动小。EtherCAT实时性的研究为EtherCAT在机器人领域的应用提供了理论基础,为EtherCAT在数控加工领域的应用提供参考。
The influence of EtherCAT real-time performance on the accuracy of SCARA robot motion trajectory is researched with the dual-camera guided manipulator bonding system as the background.The kinematics of SCARA robot is modeled,by using the standard D-H method,the parameters of the connecting rod of the robot are determined,the positive kinematics and inverse kinematics of the robot are analyzed,and the inverse kinematics solution is solved by analytic method.The kinematics of the robot is simulated by using the Robotics Toolbox of MATLAB,and the correctness of the kinematics model is verified.The real-time performance of EtherCAT is analyzed,and through the distribution clock synchronization mechanism of EtherCAT.Ethernet packets are time-stamped with the packet capture tool,wireshark packet capture software are used to analyze the dithering delay in the data transmission process,and the oscilloscope is used to measure the synchronization error,and verify the high synchronization of EtherCAT.The accuracy of the trajectory is verified on the experimental platform by using the algorithm of seven polynomial trajectory planning.The results show that the EtherCAT synchronization has small deviation and small fluctuation in speed reference and feedback.The research of the real-time performance of EtherCAT provides a theoretical basis for the application of EtherCAT in the field of robot,and has a certain reference significance for the application of EtherCAT in the field of NC machining.
作者
孙琳
张爱军
SUN Lin;ZHANG Aijun(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《自动化仪表》
CAS
2018年第11期37-41,共5页
Process Automation Instrumentation
