A two-DOF manipulator with adjustable compliance capabilities and comparison with the human finger

This article addresses compliance control issues and develops an actuator that modulates the stiffness and independently sets the angular positioning of a revolute joint. The capability to decouple the position from the compliance modulations is instrumental in a wide range of robotic contact operations. It is shown that a five input control scheme fully characterizes the position and compliance of a two-DOF manipulator. In an effort to characterize the control capabilities of a human finger, the compliance values of the proximal and middle joints are assessed experimentally. The results of the experiment show that a five input control is evidently within the human finger capabilities. In an effort to enhance the compliance capabilities of robotic systems, the authors believe that the newly developed actuation scheme will impact the automation of manufacturing tasks in which contact operations are inevitable.