Efficient Coordinated Control Strategy to Handle Randomized Inclination in Precision Assembly

Dengpeng Xing, Fangfang Liu, De Xu

Abstract: This article proposes an efficient insertion strategy for inclined precision assembly. According to the characteristics of the inclined insertion, the radial force between objects is separated into three parts: the force due to insertion, the force retained from previous compensation, and the force caused by estimation error of object inclination. We employ Gaussian distribution to model the probability of the radial force in insertion and predict the future contact based on the current force and the compensation movement. Object inclination is online estimated by peeling off the forces not related with inclination and investigating the relationship between inclination difference and radial force error. The insertion of the lower object is originated from the parameter iteratively updated by past performance, the current assessment depicting the current state, the confidence on future execution, and the coordinated motion of the upper object is then planned based on the inclined insertion, the estimated inclination, and the force to be compensated. Experiments are carried out to demonstrate the validation of the proposed method.