Decoupling and Variable Stiffness Design of Redundant Parallel Mechanism Robots in Multi Joint Training Mode

The relatively small workspace and limited range of motion of parallel mechanisms result in high coupling degree and poor output stiffness stability of robots. A decoupling variable stiffness design for redundant parallel mechanism robots based on flexible cable mechanism joint drive in multi joint training mode is proposed. Constructing a kinematic model of a redundant parallel mechanism robot under multi space trajectory planning, using a flexible cable driven method to adjust the lower limb pose of the parallel mechanism user, dynamically distributing the stress attitude adjustment of the variable stiffness joints, using a method of fitting the cam profile curve to achieve decoupling unit combination control and multi-dimensional motion space simulation of the redundant parallel mechanism robot in multi joint training mode, setting the parameters of the flexible cable mechanism joint drive model in the pivot position adjustment mechanism, and adopting a self disturbance rejection control scheme with nested inner and outer rings to achieve decoupling variable stiffness adaptive adjustment of the robot. The simulation test results show that using this method for decoupling and variable stiffness design of redundant parallel mechanism robots in multi joint training mode reduces the limited range of motion of the parallel mechanism, improves the decoupling ability of stiffness, and enhances the stability of the robot’s position and attitude control.