Variable impact dynamics of a finger mechanism

When a robot system collides with its environment, various impacts occur under the same robot and environmental condition. In order to apprehend this phenomenon, the analysis of impact dynamics is performed using a 3DOF finger mechanism. The external impulse exerted on a wall by a finger mechanism is a function of the robot´s geometry and dynamic parameters. Here, coefficient of restitution (COR) is an important parameter to calculate the impulse. Generally, COR has been assumed a constant value. However, COR varies according to the colliding condition. In this paper, we derive an analytical model of COR for the 3DOF finger model colliding with a wall, and show that COR varies according to the colliding velocity and its contact area through experiment.