Contact States Estimation Algorithm Using Fuzzy Logic in Peg-in-hole Assembly*

Abstract

Peg-in-hole assembly is regarded as one of the essential tasks in the robotic assembly. To complete the task, it is required to estimate the Contact State(CS) of a peg relative to a hole and control motions of the peg in the assembly environment. In this paper, we propose the estimation algorithm using fuzzy logic for the satisfaction of these requirements. Firstly, we describe a peg-in-hole environment, which has holes with several sizes on the surface with a fine area. Afterward, we classify the CS of the peg in the environment. Secondly, we explain and analyze the proposed algorithm and a motion control method. Using the proposed algorithm, we can estimate all the CS. After estimating the current CS, proper actions are commanded for the peg-in-hole assembly. To validate the proposed algorithm, we conducted an experiment using a 7 DOF torque-controlled manipulator and prefabricated furniture.