Control a contact sensing finger for surface haptic exploration

To efficiently explore a surface using the sense of touch, a novel contact sensing finger was created and a surface following control algorithm for the finger was devised. Based on the accurate estimation of contact locations, and the direction and magnitude of the normal and tangential forces, the finger can robustly and rapidly follow surfaces with large change in curvature while maintaining a desired constant normal force. In this paper, the design and testing of the contact sensing finger are presented and the control algorithm for surface contour following is proposed and validated using objects with different shapes and surface materials. The results demonstrate that using the developed finger and the control algorithm, a surface can be efficiently explored with rapid sliding speed. To demonstrate the potential applications of the proposed approach, the friction properties of an explored object surface are computed and, for a known object, its pose is estimated.