A compliance control strategy for robot manipulators using a self-controlled stiffness function

A compliance control strategy is proposed by using a new type of self-controlled stiffness function, where no explicit wrist force/torque sensor is employed. Specifically, the stiffness gain is given as the exponential function of the error between virtually given desired trajectory and actual trajectory, where virtual desired trajectory is designed to be inside the surface of the object to be compliance-controlled. And, a motion speed scheduling technique is also proposed to avoid serious damages due to lack of environmental knowledge and to minimally maintain the task performances. It is experimentally shown that the proposed control method is useful for various manipulator motion types such as path following, initial contact with soft impact and force regulation during contact.