Global Stiffness and Well-Conditioned Workspace Optimization Analysis of 3UPU-UPU Robot Based on Pareto Front Theory

摘要

In this paper, an approach based on the Pareto front theory is employed to conduct the multi-objective optimization of the global stiffness and well-conditioned workspace of 3UPU-UPU parallel mechanism. The inverse kinematic and Jacobian matrix of the 3UPU-UPU mechanism are first calculated. Then the stiffness model of the mechanism is derived and the sum of the diagonal elements of the stiffness matrix is used as a criterion to evaluate the global stiffness. Secondly, the Monte Carlo method is used to derive the global condition index of the mechanism which later is used as a criterion to evaluate the well-conditioned workspace of the mechanism. Normally, increasing the workspace of the mechanism will deteriorate the stiffness, here the global stiffness and well-conditioned workspace of the mechanism are optimized simultaneously based on the Pareto front theory, and the optimized results are displayed and compared.