Positioning accuracy reliability analysis of industrial robots based on differential kinematics and saddlepoint approximation

Abstract

This paper proposes a new positioning accuracy reliability analysis method based on the differential kinematics and saddlepoint approximation to evaluate the influence of kinematic parameter uncertainties on the robotic motion. Firstly, considering the reliability analysis instability caused by complex nonlinear limit state function, the reliability model of positioning accuracy is established based on the differential kinematics and error propagation. Subsequently, the parameters of the position error distribution are deduced analytically to combine with the eigen-decomposition to complete the modeling of the cumulant generating function, thereby the kinematic reliability is yielded according to the saddlepoint approximation method. Finally, the comparative analysis of a six degrees of freedom serial industrial robot is conducted and the results of which demonstrate that the proposed method provides a better performance than the existing methods in terms of accuracy and efficiency for kinematic reliability analysis.