Kinesthetic Sensing for Peg-In-Hole Assembly Based on In-Hand Manipulation

Abstract

This study proposes a new way of estimating the hole direction to reduce the search time deviation in peg-in-hole assembly. To perform a peg-in-hole assembly, the hole position has to be found. In our previous studies, we found the hole using a blind search method. The blind search method moves the peg in a predefined path until it finds the hole. However, using blind search, it is difficult to predict the peg-in-hole assembly completion time because hole position search time is different each time. This is because the peg moves along the same predefined path without considering the hole direction. Furthermore, if the direction of the hole is known, the hole search time deviation can be reduced compared to when the direction of the hole is not known at all. Therefore, we propose a new way of finding the hole direction using in-hand manipulation based on ‘kinesthetic sensing’. Additionally, we introduce the concept of ‘Free-Finger’ for in-hand manipulation. The proposed method uses fingers to find the hole direction and perform the peg-in-hole assembly. Hence, we can implement peg-in-hole assembly regardless of the performance of the manipulator. The feasibility of the proposed method was verified through experiments using a three-fingered gripper.