The constant-Jacobian method for kinematics of a three-DOF planar micro-motion stage

This paper concerns the development of a class of devices that generate end-effector motion in the range of less than 100 gm and with sub-nanometer resolution; in particular, a parallel manipulator configuration that generates a planar x-y-gamma motion is considered. The parallel manipulator is implemented as a compliant mechanism. A problem with parallel manipulators is that the forward kinematics is usually too complex, which can hinder the implementation of advanced control algorithms. The contribution of this paper is that a simple method, called the constant-Jacobian (Q) method, is developed based on the pseudo-rigid body (PRB) approach to compliant mechanisms. The experiment validates the CJ method. (C) 2002 John Wiley Sons, Inc.