| With the upgrading of traditional manufacturing industry and the rapid development of intelligent manufacturing technology,industrial robots are more and more widely used in automatic production.As the basis of robot motion control,trajectory planning is also a subject of much attention and research.However,the actual robot system is expensive,long development cycle and low efficiency,which can not meet the rapid development needs of robots.Compared with pure physical simulation,hardware in the loop simulation platform can shorten the development cycle,reduce the cost and risk,and is more authentic and credible than pure mathematical simulation.Therefore,based on the research and analysis of joint space trajectory planning algorithms of industrial robots at home and abroad,in order to solve the problem of residual vibration of joint axis in the process of trajectory planning of common interpolation algorithms,a third-order continuous improved multi node spline trajectory planning method is proposed,and a set of hardware in the loop simulation platform based on EtherCAT communication is built to verify the algorithm.Firstly,this paper takes the 4-DOF SCARA robot as the research object.Based on d-H method,the kinematics model is built according to its mechanical structure,and the forward and inverse kinematics analysis is carried out to deduce the singularity position.In the Matlab environment,the robot tool library was used to build the connecting rod model,verify the correctness of the forward and inverse kinematics solving equations,analyze and compare the advantages and disadvantages of common interpolation algorithms such as polynomial interpolation and spline interpolation in detail,and carry out trajectory planning simulation in the joint space to obtain the trajectory of each joint.Secondly,aiming at the requirements of rapid robot development and cost saving,this paper carried out research on master station of motion control and slave station of drive based on EtherCAT communication,designed and built master station hardware platform based on STM32F407 master chip and interface chip DP83848,and analyzed the design of main circuit interface.The huichuan servo driver was selected as the slave station,data communication was realized through IOmap mapping,and the control program was written into the master station to realize real-time motion control of the slave station.Thus,a servo control platform with one master and two slaves based on EtherCAT communication was built.The 3D model of the robot was built in Solidworks,and the SCARA simulation model was built by importing it into Matlab/Simulink.The h WIL simulation platform was built by connecting EtherCAT master-slave system and simulation model.After that,the multi-node spline interpolation algorithm is introduced and derived.Compared with spline interpolation,the algorithm has local support and will not affect the whole curve due to the change of individual points.Compared with B-spline,the algorithm can accurately pass through the type value points without solving equations.Based on multiple nodes increase extension point,make the velocity and acceleration of the path to zero in order to satisfy the demands of trajectory planning,at the same time,by introducing additional function to improve the algorithm to solve the traditional three times more nodes third-order spline interpolation jump discontinuity cause joints to produce residual vibration problems,and the correctness of the theoretical deduction is verified by the simulation analysis.Finally,EtherCAT communication system and simulation model were connected to build a hardware-in-the-loop simulation platform to test the feasibility of the platform and realize the control of the master station on the robot model.The improved multi-node interpolation algorithm was written into the control program of the master station,and the feasibility of the algorithm was verified through the hardware-in-the-loop simulation platform by comparing the experimental results,and the expected goal was achieved. |
