Research On The Control Strategy Of 3-dof Translational Parallel Tele-manipulator

The bidirectional servo control system based on force tele-presence is the critical section of master-slave robots. How to calculate the correct and actual force feedback according to the slave arm’s position and force information and how to design a reasonable controller to improve the stability of servo system dynamic and static performance is an important topic of tele-operation system.This M.E. dissertation developed under the project named “Tele-operation multi-DOF electro-hydraulic servo parallel manipulator with accurate force feedback”(No. 50975118).According to 3-dof translational parallel manipulator, one new control strategies based on position constraint space is proposed.3-DOF parallel mechanism is designed in this paper according to the 6-DOF parallel mechanism’s disadvantages such as small movement space, calibration difficult and movable platform position and direction of the strong coupling faults. The kinematic positive solution and inverse solution equations and Lagrange dynamics equation of the workspace and singularity problems were deduced.According to the question that traditional bilateral servo control strategy cannot accurately reflect the feedback in the direction and size of the force from the end, one new control strategy based on position constraint space was proposed, the feedback force information is optimized from the point of view of the constraint of motion space. The methods of establishing the constraint equations of two kinds of constraints which are formed by the restriction of the structure and the constraint of the environmental obstacles are discussed. The general method of constraint space equations is derived.Controller is designed for the driver PMSM of the manipulator. In this paper, a PID controller based on fuzzy logic parameter tuning is used. On the basis of traditional PID control, the parameters of the fuzzy control rules are determined by using the fuzzy control rules; it improves the dynamic and static characteristics of the system greatly.Through Simulink modeling of the translational parallel mechanism with three degrees of freedom, and build a master slave servo system. The control effect of traditional control strategy and the new control strategy based on comparison was compared.Simulation results show that, In the system using servo control strategy based on position space, the size and direction of the interference force from the end of the reaction can be more accurate from the hand,it will make the system more realistic.