Compliance analysis of a horizontal arrangement parallel mechanism considering gravitational effect

Abstract

A novel polishing machine with serial-parallel mechanism is presented. Since the machine make use of horizontal layout, the gravity of the moving part causes deformation of the end-eff·ector and affects the machining accuracy. As a result, it is essential to analyze the deformation due to gravitational effect. Firstly, the structure and working principle of the serial-parallel polishing machine is introduced. Secondly, the compliance model of the parallel mechanism is formulated based upon the virtual work principle and the deformation superposition principle. The compliance model is established by taking both the deformations of leg system and drive system into account. Hence, the gravity of all moving components and the corresponding deformations are calculated. The results show that gravity has a greater effect on the positional accuracy of the machine. This investigation will provide informative guidelines for optimal stiffness design and gravity compensation of the polishing machine.