Research On Posture Tracking Control Of Parallel Four Degree Of Freedom Movement Platform

The parallel four-degree-of-freedom motion platform is mainly used to simulate the actual posture of the vehicle.During the simulation experiment,the tracking effect of the platform on a given target pose directly determines the degree of goodness of the simulation experiment.Therefore,the tracking of pose has strict accuracy requirement.Due to the influence of external disturbance forces and joint coupling forces during platform motion,the traditional control method can no longer meet the control accuracy requirements.Therefore,it is necessary to design a motion controller with high control accuracy and strong anti-interference ability.This paper based on the actual engineering project,the parallel four freedom motion platform is used as the research object,and aims to improve the control precision of the platform,and makes the following research:First,the platform was kinematically modeled.Combining space description and coordinate transformation,the inverse solution equation and positive solution equation of the parallel four-degree-of-freedom motion platform are given,which lays the foundation for the tracking control of the platform.Secondly,according to the overall control strategy based on the joint space,a mathematical model was established for a single servo joint branch,and then an autodisturbance disturbance was designed based on the uncertainty of the internal parameter setting of the system and the coupling forces between the joints.The controller performs simulations on the pose of the single-joint servo branch and the entire platform.Thirdly,in order to further improve the response speed of the system,a study was conducted.A sliding mode controller based on an extended state observer was designed.Combined with platform kinematics analysis,the simulation of the pose of the single joint servo branch and the entire platform was performed.The effectiveness of sliding mode controller based on extended state observer is provedFinally,according to the platform's control requirements and algorithm implementation requirements,the control system of the parallel four-degree-of-freedom motion platform was designed,the hardware selection and construction were completed,and the upper computer program and the lower computer program were designed,and the upper computer was implemented.The communication between the lower computers lays the foundation for the realization of the algorithm in the actual system and the debugging of the later platform.