Control of whole finger manipulation utilizing frictionless sliding contact—theory and experiment

Abstract

We propose a whole finger manipulation (WFM) to improve the robustness of manipulation by a multifingered robot hand. The WFM is characterized by enveloping an object by finger links of the multifingered robot hand, and utilizing the frictionless sliding contacts between the surfaces of finger links and the grasped object. Therefore, the WFM can achieve a large manipulation without regrasping the object and can be highly robust in nature because of form-closure due to multiple contact points on the grasped object. This paper discusses the property and control of the WFM. The WFM with frictionless contact is shown to be a manipulable and force closure grasp using kinematics and statics with frictionless sliding contact. We discuss that the force closure for the WFM with frictionless contact can be viewed as form closure. An internal force-based impedance control is proposed for the stable manipulation in consideration of sliding contacts between the object and the finger links. A prototype hand and sensing systems are presented. The validity of the proposed control law is verified through the experiments.