Pulling motion based tactile sensing for concave surface

An algorithm for detecting the shape of a 2D concave surface by utilizing a tactile probe is proposed. Pulling a tactile probe whose tip lies on an object's surface can be easily achieved, while pushing it is more difficult due to stick-slip or blocking up with an irregular surface. To cope with the difficulty of pushing motion on a frictional surface, the proposed sensing algorithm makes use of the pulling motion of a tactile probe from a local concave point to an outer direction. The algorithm is composed of three phases, local concave point search, tracing motion planning, and infinite loop escape. The proposed algorithm runs until the tactile probe detects every surface which it can reach and touch. We show some computer simulations and experimental results obtained with the proposed algorithm.