Structure Optimization Design of 3-UPU Parallel Mechanism Based on the Comprehensive Dexterity

Abstract

There are different kinematics and static stiffness characteristics for different structure parameters of the same type Parallel mechanism. So the reasonable design of the structure parameters becomes a key problem of parallel mechanism structure design. In this paper, the structure parameter optimization design method of 3-UPU parallel mechanism is proposed based on the comprehensive dexterity. First, the position mathematical model of Parallel mechanism is derived and the Jacobi matrix is established. By two methods (the condition number evaluation and the comprehensive dexterity evaluation), the structure parameters optimization design of 3-UPU parallel mechanism is proposed. Through analysis, the latter is superior to the former. The parallel mechanism structure parameters are optimized by the latter. The results show: In the known workspace and the considered mechanism structure, when the comprehensive dexterity is 1.26≤e𕟩.28 , the optimized parameters meet the design requirements. And the data is beneficial for the error analysis of parallel mechanism. Keywords: 3-UPU parallel mechanism, the condition number, the structure optimization, Jacobi matrix, the comprehensive dexterity.