Dynamic Control of Internal Force for Visco-Elastic Contact Grasps

This paper deals with robotic grasps exhibiting viscoelastic contact interactions with the manipulated object. Such interactions are frequent in advanced robotic applications since in many cases, i.e. when a great precision is needed, elasticity cannot be neglected. This is particularly true in medical applications, as in tele-surgery or in laparoscopy, where precision is obviously basic. The control of internal forces f o r visco-elastic grasps is explored in this work. This i s a n important issue in tele-operated robotics (tele-surgery and so forth). The presence of non-negligible compliance at the contacts, implies that the object dynamics cannot be neglected when attempting to control internal forces without affecting the object position. A geometric approach to derive a control law dynamically decoupling the internal force control action f rom the object dynamics is proposed. Figure 1: Micromanipulation of internal tissues in surgery or laparmcopy.