Assembly of randomly placed parts realized by using only one robot arm with a general parallel-jaw gripper

TL;DR

This paper presents a novel method for integrating parts feeding and assembly using a single robot arm equipped with a specially designed gripper, enabling in-hand manipulation to improve assembly flexibility and reduce costs.

Contribution

It introduces a new gripper design and in-hand manipulation technique that allows a single robot arm to perform both part feeding and assembly tasks.

Findings

Successful simulation of peg-in-hole assembly using the proposed method.

Enhanced flexibility in assembly process with reduced need for multiple devices.

Potential cost savings by combining feeding and assembly in one robot system.

Abstract

In industry assembly lines, parts feeding machines are widely employed as the prologue of the whole procedure. They play the role of sorting the parts randomly placed in bins to the state with specified pose. With the help of the parts feeding machines, the subsequent assembly processes by robot arm can always start from the same condition. Thus it is expected that function of parting feeding machine and the robotic assembly can be integrated with one robot arm. This scheme can provide great flexibility and can also contribute to reduce the cost. The difficulties involved in this scheme lie in the fact that in the part feeding phase, the pose of the part after grasping may be not proper for the subsequent assembly. Sometimes it can not even guarantee a stable grasp. In this paper, we proposed a method to integrate parts feeding and assembly within one robot arm. This proposal utilizes a specially designed gripper tip mounted on the jaws of a two-fingered gripper. With the modified gripper, in-hand manipulation of the grasped object is realized, which can ensure the control of the orientation and offset position of the grasped object. The proposal in this paper is verified by a simulated assembly in which a robot arm completed the assembly process including parts picking from bin and a subsequent peg-in-hole assembly.