Fine motion control based on constant criteria under pre-loading configurations

This article discusses the fine motion control and extreme bounds on the ma ximum displacements allowed under pre-loading configurations in a robotic g rasp. Fine motion is achieved by applying a preload at a contact to gain th e desirable motion in a desirable direction under required sufficient contr aints proposed in this paper. A particular one is the constraint of a resto ring torque resulting at each contact due to the fine motion caused by the application of suitable forces through the contact. These forces are provid ed as preloads or the effect of preloads which can be applied through two t ypes of pre-loading configurations, one of which is to apply a preload para llel to a contact normal and the other is through the contact normal. The a rticle proposes mathematical models for both types of pre-loading configura tions and introduces optimal preload for fine motion control in a grasped o bject. Examples are given in the article to support the theoretical base. ( C) 2000 John Wiley & Sons, Inc.