Kinematics Analysis And Motion Control Research Of Tripod Parallel Robot

With the decrease of the population bonus and the increase of labor cost, the industrial robot has been widely used in order to improve the product quality and production efficiency. The parallel robot with the advantages of high dynamic response, high stiffness and high accuracy, is widely used in food industry, light industry, electronic products and other industries, to realize the automatic sorting, grab, packaging and other repetitive operations. In this paper, the Tripod parallel robot is studied in the aspects of kinematics analysis, trajectory planning, electronic control system design and control strategy.Firstly, based on the analysis of mechanism and the solution of the degree of freedom, the coordinate system is established, and the inverse kinematics also the forward kinematics are solved by using the algebraic vector method and the numerical method; Based on the kinematics equation, the calculation of Jacobian matrix is realized by using the differential transformation method; The limit boundary searching method based on the inverse kinematics is used to analyze the workspace of the robot.Secondly, the theory of robot trajectory planning is studied deeply, the modified trapezoidal acceleration is used to realize the trajectory planning of the typical grab operation of the Tripod robot in Cartesian space and joint axis space respectively, this provides trajectory basis for motion control.Thirdly, the electronic control system of the physical prototype is designed to build a performance test platform with the use of KeMotion professional controller; The design scheme of open electronic control system based on PC is put forward, the hardware architecture is completed by using the PC controller and the servo system of EtherCAT bus, and the whole control framework of software is constructed based on the TwinCAT3 software and the kinematics model.Fourthly, the control system of the Tripod parallel robot is simplified as the single input and single output subsystem of the three motion branch chains by using the control strategy based on the kinematics model, also the design and simulation analysis of fuzzy PI controller are carried out on the basis of the traditional PID controller.Lastly, ADAMS software is used to carry out the kinematics simulation of the virtual prototype which can verify the kinematics performance and the kinematics model; The feasibility of the trajectory planning based on the modified trapezoidal acceleration, the correctness of the inverse kinematics and the superiority of the fuzzy PI control algorithm are verified by the simulation combined with the MATLAB software; The test of motion performance and repeated positioning accuracy is carried out on the physical prototype based on KeMotion controller, and the results show that the Tripod parallel robot has good motion performance, and the repeated positioning accuracy of y、z direction meets the requirement of ±0.1mm, x direction exceeds slightly when at high speed.