Error Sensitivity Analysis of a Six-DOF Stewart Platform

Abstract:
Position errors of joints and actuators errors exists in the transmission link of the parallel mechanism, which has a great impact on the accuracy of the target platform. In order to improve the compensation accuracy, an error function model is established in this paper. The error model of the Stewart platform is established based on the modeling method of spatial error-vector chains. And then the mapping function between the geometric error parameters and the output error parameters are generated. On the basis of the error model, the global sensitivity index and the local sensitivity index of each geometric error parameter are derived and presented in histograms and graph. Based on the histograms and graph, the geometric error parameters’ influence on the output accuracy of Stewart platform is identified numerically. The results contribute a lot to the determination of the parts’ tolerance and the output error of the control system.