Decoupling Design Of 2T1R Parallel Mechanism And Its Kinematics,Stiffness And Dynamic Analysis And Optimization

According to the topology design theory and method of parallel mechanism based on orientation feature set,an asymmetric three degree of freedom parallel mechanism with two translation and one rotation is designed,and its coupling reduction design is carried out.The kinematic performance,stiffness performance and dynamic performance of the two mechanisms are analyzed and optimized.Firstly,the topological characteristics such as degree of freedom,POC set and coupling degree of the mechanism are analyzed.It is found that the coupling degree of the mechanism is κ=1,and the symbolic position positive solution can not be obtained,which is not conducive to the subsequent kinematic synthesis and dynamic analysis.Therefore,the topological decoupling design of the mechanism is carried out,and a basic method is obtained.This function(DOF,POC)remains the same zero coupling degree 2T1 R mechanism,and has symbolic position forward and inverse solution and input-output(I-O)motion decoupling.Establish the topological characteristic kinematics model of the two mechanisms before and after decoupling,and obtain the position forward solution of the mechanism.Derive the Jacobian matrix of the mechanism,obtain the singular configuration of the mechanism,calculate the workspace,and compare the two mechanisms before and after decoupling.Furthermore,taking the scale parameters as the design variables and the maximum workspace as the objective function,the workspace of the two mechanisms before and after decoupling reduction is optimized by using DE algorithm,and the workspace of the two mechanisms is compared and analyzed.Secondly,based on the virtual spring method(VSM),the stiffness models of the above two mechanisms are established,the change trend of torsional stiffness and linear stiffness is calculated and analyzed,and the stiffness of the mechanism after decoupling reduction is verified by ANSYS.Furthermore,taking the section parameters as the design variables and the maximum torsional and linear stiffness of the mechanism as the objective function,the DE algorithm is used to analyze the two mechanisms before and after decoupling reduction Stiffness optimization is used to improve the stiffness performance,and the stiffness performance of the two mechanisms is compared and analyzed.Finally,the velocity and acceleration of each member of the mechanism are obtained through the inverse position solution.The reverse dynamic modeling and analysis of the two mechanisms are carried out by using the sequential single open chain method based on the principle of virtual work.The dynamic models of the two mechanisms before and after decoupling are established.The driving torque of the mechanism and the reaction of the two kinematic pairs of the sub kinematic chain are solved,and the dynamic simulation is carried out by Adams Furthermore,taking the mass parameters of the bar as the design variables and the maximum energy transfer efficiency as the objective function,the dynamic performance of the mechanism is optimized,and the dynamic performance of the two mechanisms is compared and analyzed.