Multi-robot control for flexible fixtureless assembly of flexible sheet metal auto body parts

摘要

This paper addresses methods of control of a multi-robot system designed for the assembly of flexible sheet metal parts. The work begins with the dynamic modeling of two robots and their sheet metal payloads. Recognizing that the flexible sheet metal states are practically unobservable, since none of the sheet metal parts will be instrumented, a practical control algorithm is proposed based on the rigid body dynamics of the robot and payloads. Stability analysis is carried out using the theory of singularly perturbed dynamic systems to determine the effect of the "rigid" feedback on the flexible system. Experimental results are given to illustrate the dynamic response of the two robot system, while carrying out the assembly operation with the two robots under force control. The experiments are performed with two 6-DOF commercial industrial robots.