Reconstruction of the inverse kinematic solution subject to joint kinematic limits using kinematic redundancy

Abstract

Various physical limitations which intrinsically exist in the manipulator inverse kinematic system, e.g. joint travel and velocity limits, induce inevitable motion errors. This paper is concerned with how to reconstruct such an inverse kinematic solution using redundancy, in order not to produce any task motion error. By analyzing the error due to hardware limitations with respect to the kinematically decoupled coordinates, we are able to show that the recoverability of limitation reduces to the solvability of a reconstruction equation under the feasibility condition. It will be next shown that the reconstruction equation is solvable if the configuration is not a joint-limit singularity. The reconstruction method will be proposed based on the geometrical analysis of recoverability of hardware limitations. The method has the feature that no task motion error is induced by the hardware limitations while minimizing a possible null motion error under the recoverability assumed.