Research On Pose Tracking Control Of Six Degree Of Freedom Parallel Platform

The main research content of the six-degrees-of-freedom(6-DOF)parallel platform is pose tracking control in component assembly and actual motion simulation of military vehicles.However,due to the strong coupling and nonlinearity of the 6-DOF parallel platform motion,it is also affected by deterministic and uncertainty interference,this requires that the control system can suppress the disturbances to realize fast and stable pose tracking of the platform.The pose tracking control of 6-DOF parallel platform is studied according to this control requirement.Firstly,using the rigid body's position and pose transformation in space,the inverse kinematics model of the 6-DOF parallel platform is established.The forward kinematics model of the platform is obtained by back propagation(BP)neural network model and Newton-Raphson iterative algorithm.Secondly,a control strategy is adopted based on articulated space,each branch of the 6-DOF parallel platform is regarded as a controlled object,and a mathematical model is established for the hydraulic branch of the parallel platform,a controller is designed for each hydraulic branch.In order to realize the stability and robustness of hydraulic branch position control,when there is known interference in the parallel platform system,a backstepping sliding mode controller based on improved reaching law is designed.Thirdly,for the unknown external disturbance to the 6-DOF parallel platform and the “differential explosion” problem in backstepping control,a based on extended observer dynamic surface backstepping sliding mode controller is designed base on improved reaching law backstepping sliding mode algorithm.And since the traditional extended observer has a peak phenomenon,the traditional extended observer is improved,so that the improved extended observer can suppress the peak phenomenon,and has better observation accuracy and convergence speed.Finally,through the 6-DOF parallel platform branch displacement tracking control and the overall pose tracking control simulation experiment,the validity of the kinematics forward and inverse solution model and control method of the 6-DOF parallel platform will be verified.