Safe grasping in presence of multi phase friction

Robotic systems which are supposed to handle delicate objects should grasp them with minimum possible force. This causes the system to practice slip mode, incipient slip mode and non-slip mode between object and gripper during the course of motion. It is a common practice among researchers to simplify this multi-phase friction to a single mode motion. This paper investigates the effect of such simplifications made in the dynamic model of Columb friction. Both on the predicted motion of the object and on the grasping force applied to hold the object in non-slip mode. A simple and yet sophisticated control law is also presented which shows good capability of tracking and force control at the same time.