Identification and control of haptic systems : a computational theory

摘要

This thesis provides a theoretical framework for haptics, the study of exploration and manipulation using hands. Be it human or robotic research, an understanding of the nature of contact, grasp, exploration, and manipulation is of singular importance. In human haptics the objective is to understand the mechanics of hand actions, sensory information processing, and motor control. While robots have lagged behind their human counterparts in dexterity, recent developments in tactile sensing technology have made it possible to build sensor arrays that in some way mimic human performance. We believe that a computational theory of haptics, that investigates what kind of sensory information is necessary and how it has to be processed is beneficial to both human and robotic research. Human and robot tactile sensing can be accomplished by arrays of mechanosensors embedded in a deformable medium. When an object comes in contact with the surface of the medium, information about the shape of the surface of the medium and the force distribution on the surface is encoded in the sensor signals. The problem for the central processor is to reliably and efficiently infer the object properties and the contact state from these signals. In the first part of the thesis w e discuss the surface signal identification problem: the processing of sensor signals resulting in algorithms and guidelines for sensor design that give optimal estimates of the loading and displacement distributions on the surface of the fingerpad. In the second part of the thesis we focus on how the information obtained from such optimal sensing can be used for exploration of objects. We argue that an accurate reconstruction of object properties can occur using two basic building blocks of Exploration Strategy and Finger Control.