Tactile Sensing for Shape Interpretation

Dextrous robot hands require intelligent sensing systems to manipulate unknown objects reliably in a complex environment. Tactile sensing and perception are needed to provide information on contact forces and local shape properties to ensure robust manipulation. This chapter considers the problem of inferring global object properties such as size, location and orientation from only sparse local geometric information at three fingers. Tactile sensors can provide local shape information, including surface normals, contact location on the finger, and principal curvatures and their directions. This chapter assumes that an object is a cone (not necessarily circular) but is otherwise unknown. Three contacts can in some cases determine the pose of an unknown cone, but in general, more are required. A grasping system could command finger forces to control an object’s position in a hand using this tactile information. The advantage of not using specific object models is that a system will be flexible enough to handle a wide range of parts without reprogramming, and will be robust to gross and small differences among objects.