Feature Detection for Haptic Exploration with Robotic Fingers

The authors consider the detection of small surface features, such as cracks, bumps, and ridges, on the surface of an object during haptic exploration and dexterous manipulation. Surface feature definition and detection are essential for intelligent haptic exploration and modeling of unknown objects. First, the authors review the representation of object surface geometry and present definitions of features based on local surface curvature. These definitions depend on both the geometry of the robot fingertips and the object being explored. It is also shown that the trajectory traced by a round fingertip rolling or sliding over the object surface has some intrinsic properties that facilitate feature detection. Several algorithms for feature detection based on feature definitions are described and compared, and simulated and experimental results are presented for feature detection using a hemispherical fingertip equipped with a tactile sensor.