Controlling force variations during soft-tissue grasping
This paper develops a mechatronic grasper that can be used to investigate a preliminary experiment of a simple model-independent approach to control soft-tissue grasping based on, first, measurement of the total tangential grasp force and, second, discrimination of relaxation and frictional forces by imposing a limited basis set of grasper motions. The main motivation for this work is that tissue grasping is an important component of surgical procedures. However, there is a major criterion which should be achieved: maintaining grasp stability while avoiding damage due to excessive grip force. Thus, the automation of grasping force control requires a controller to apply grasping forces just sufficient to maintain grasp stability. This task is complicated by the serially connected dynamics of grasp friction and tissue relaxation.