Tactile Measurement of Local Contact Geometry Using Soft Fingertip with Force/Torque Sensor

We propose a new method of tactile sensing for a fingertip of robotic hand based on the analysis of the mechanical constraints imposed to the contact between the fingertip and the contacting object. Using a simple fingertip with soft surface cover and a six-axis force/torque sensor, a new function is developed to measure direction of local geometry of a class of objects when the fingertip contacts with them. The developed function is useful not only to plan strategies for stable grasp and dexterous manipulation but also to recognize a geometrical shape of an object. Two necessary components, a six-axis force/torque sensor and a soft skin, are commercially available. They neither restrict design of a robotic fingertip nor badly affect essential functions of stable grasping and manipulation