Dynamic simulation of multi-fingered robot hands based on a unified model

In dextrous manipulation of multi-fingered robot hands, the contact motions between the fingers and the grasped object may frequently change between sticking, rolling, and sliding. Furthermore, when a robot hand is to re-grasp an object, the number of fingers in contact with the grasped object will change and impulsive collisions will occur. In order to cope with these different cases, this paper proposes a unified framework to model the dynamics of a multi-fingered hand in free motion, collision, and different contact motions including sticking, rolling, sliding, and their combinations. The introduction of a contact motion selection matrix enables us to unify dynamic equations for different motions into a single model. To calculate the collision response, we adopt the impulse-based method proposed by Mirtich. A new contact transition model is also developed to identify the type of contact motion between a finger and the grasped object. Based on the unified dynamic model, we have developed a 3D dynamic simulator to simulate dextrous manipulation of a five-fingered robot hand. The validity of the dynamic simulator is verified by examples. (C) 2000 Elsevier Science B.V. All rights reserved.