Stiffness control of the coupled tendon-driven robot hand

This paper presents the methods of design and control for a coupled tendon-driven robot hand with stiffness control capability. By using the tendon as a force transmission mechanism, we can achieve the compact design of the robot hand. Because of the tendon characteristics, we consider the tendon slacking problem when the joint is unexpectedly disturbed and the tendon elongation problem when the collocated position sensing method is used for compact design. To cope with these problems, two fundamental algorithms are developed. First, the position estimation algorithm is developed to evaluate the accurate position of the hand, and an antagonistic tendon controller is introduced. Secondly, the active stiffness control algorithm is developed to control the fingertip force