The kinematic decoupling of parallel manipulators using joint-sensor data

In this paper we decouple the translational and rotational degrees of freed om of the end-effector of parallel manipulators, and hence, decompose the d irect kinematics problem into two simpler subproblems. Most of the redundan t joint-sensor layouts produce a linear decoupling equation expressing the least-square solution of position for a given orientation of the end-effect or. The resulting orientation problem can be cast as a linear algebraic sys tem constrained by the proper orthogonality of the rotation matrix. Althoug h this problem is nonlinear, we propose a procedure that provides what me t erm a decoupled polar least-square estimate. The resulting procedure is fas t, robust to measurement noise, and produces estimates with about the same accuracy as a Procedure for nonlinear systems if sufficient redundancy is u sed.