An efficient method for system reliability analysis of planar mechanisms

Abstract

This article presents an efficient method for system reliability analysis of planar mechanisms with random dimensions and joint clearances. The reliability of the mechanism is defined as the probability that the output error remains within a specified limit in the entire target trajectory of the mechanism. Since the currently used methods for system reliability analysis are approximate in nature, this article presents a more efficient and innovative method based on the minimum cross-entropy principle for probabilistic analysis used in the information theory. The mechanism reliability problem is formulated as a series system reliability analysis that can be solved using the distribution of maximum output error. To derive this distribution, fractional moments of the output error are estimated from a small simulated sample of trajectories of mechanism motion which serve as constraints in the minimization of cross entropy. The proposed method is illustrated by analyzing the reliability slider–crank and a four-bar function generator. The comparison of the results with those obtained from the Monte Carlo simulations confirms the high accuracy of the proposed method.