Research On Structural Parameters Optimization And Control System Of Parallel Platform

Six degrees of freedom parallel platform is an important branch of the field of research,with strong load capacity,small cumulative error,structural rigidity,high control accuracy,widely used in machine tools,antenna positioning,motion simulation,spacecraft docking and other fields.In this paper,the six-degree-of-freedom parallel platform is mainly applied to antenna positioning,and its pose error directly affects the accuracy of antenna positioning.Therefore,the design control of high precision,good dynamic performance of the parallel platform has a very important significance.In order to improve the performance of the parallel platform,this paper mainly focuses on the structural optimization of the parallel platform and the design of the controller.For the optimization of the structural parameters of the parallel platform,a structural parameter optimization algorithm based on the multi-objective and multi-constraint method is proposed.The optimal structural parameters of the parallel platform are obtained.For the controller design of the parallel platform,this paper presents two control methods,position control method based on speed feedforward and force control method based on virtual model.Design simulation experiments to verify the effectiveness of the method.The main contents of this paper are presented as follows:(1)Firstly,the paper shows the research background,as well as the the research process of parallel platform,and then the main research content and the organization of this paper is introduced.(2)The kinematics model of parallel platform.In this paper,the simplified structure of the 6-DOF parallel platform is given and the degree of freedom is calculated.The inverse kinematics,Jacobi and positive kinematics of the parallel platform are obtained.(3)Structural Parameters Optimization of Parallel Platform.In this paper,the workspace and dexterity of the parallel platform are analyzed.A method of optimizing the structural parameters of the parallel platform based on multi-objective and multi-constraint is designed.According to the working space and the dexterity index of the parallel platform,the objective function is established and the constraint condition is defined.The Monte Carlo method is used to implement the parameter optimization process.(4)Design of controller for parallel platform.In this paper,the trajectory planning method of parallel platform is introduced,and the position control method based on velocity feedforward and the force control method based on virtual model are proposed.The controller of parallel platform is designed according to these two control methods.(5)Simulation Design and Analysis of Parallel Platform.Using the Webots simulation software to build a parallel platform simulation model.Design the relevant experiment to verify the two control methods,position control parallel platform controller and the parallel platform controller based on virtual model.The experimental results show that the parallel platform controller designed in this paper can obtain better performance,and the control method is feasible.(6)The paper summarize the work done and innovations of this research,and looking forward to the future work.