Haptic exploration of fine surface features

We consider the detection of small surface features, such as ridges and bumps, on the surface of an object during dextrous manipulation. First, we review the representation of object surface geometry and present definitions of surface features based on local curvature. These definitions depend on the geometries of both the robot fingertips and the object being explored. We also show that the trajectory traced by a round fingertip rolling or sliding over the object surface has some intrinsic properties that facilitate feature detection. Next, several algorithms based on the feature definitions are presented and compared. Finally, we present simulated and experimental results for feature detection using a hemispherical fingertip equipped with an optical tactile sensor.