Dynimics Analysis And Control Strategy Research Of Redundantly Actuated Parallel Manipulator

As one kind of over-constraint parallel manipulators,redundantly actuated parallel manipulator possesses number of linearly independent actuation exceeding its degrees of freedom.As the actuation input takes high coupling,actuation coordination becomes one of the most important issues of redundantly actuated parallel manipulator.This paper takes a parallel manipulator 6PUS+UPU as the main object and operates the study about the dynamic model,performance analysis and optimization of driving force distribution about redundantly actuated parallel manipulator.Driving force coordination mechanism with actuation redundancy is analyzed and relative control strategy is studied.(1)Based on principle of virtual work,uniformed dynamic model of redundantly actuated parallel manipulator 6PUS+UPU is established.Comparison of dynamic performance of manipulators 6PUS+UPU and 6PUS is made,and influence of constraint limb UPU to the dynamic performance of manipulator is studied with numerical examples.(2)Combining screw theory and branch dynamic model,driving force distribution of manipulator 6PUS+UPU with considerating elastic deformation is derived.Rigid-flexible dynamic simulation is carried out,and influence of branch stiffness to the driving force distribution is analyzed.(3)Influence of actuation error to motion accuracy and driving force distribution is analyzed.Driving force coordination mechanism of general redundantly actuated parallel manipulator is studied and two new indexes to evaluate driving force coordination performance are proposed.Application of new proposed indexes in optimizing control strategy of redundantly actuated parallel manipulator is analyzed.(4)With branch dynamic model,active internal force control strategy of redundantly actuated parallel manipulator is proposed,and with driving force coordination performance index,driving force synchronous control strategy is proposed.Neural network is involved to potimize the intelligent control algorithm.Mechatronic simulation validates the effectiveness of proposed strategies.(5)Active internal force control strategy and driving force synchronous control strategy are operated on the prototype of manipulator 6PUS+UPU,and comparison with traditional force-position hybrid actuation model is carried out.Experimental result validates the effectiveness of proposed strategies on the control of manipulator's force states.The content of this paper takes referential significance to the research of structure optimization,driving force distribution optimization,performance analysis and evaluation,control strategy improvement and practical application of redundantly actuated parallel manipulator.