On estimating local shape using contact sensing

In this paper we investigate an exploratory procedure (EP) for determining the local shape or curvature of objects with curved surfaces, using contact sensing by a dexterous robotic agent. The EP is based on rolling a probe ( a finger) on the surface of an unknown object. Using the known geometry of the probe tip (fingertip) and the sensed displacement of contact point, we use kinematic equations for two rigid bodies in contact to estimate the cur vature of the unknown object at a point. We demonstrate this approach with simulations and analyze its sensitivity to noise caused by sensing and meas urement errors. This local information can then be used in the global objec t shape reconstruction algorithms. (C) 2000 John Wiley & Sons, Inc.