RECONSTRUCTION OF THE INVERSE KINEMATIC SOLUTION SUBJECT TO JOINT KINEMATIC LIMITS USING KINEMATIC REDUNDANCY

Various physical limitations which intrinsically exist in the manipula tor inverse kinematic system, e.g. joint travel and velocity limits, i nduce inevitable motion errors. This paper is concerned with how to re construct such an inverse kinematic solution using redundancy, in orde r not to produce any task motion error. By analyzing the error due to hardware limitations with respect to the kinematically decoupled coord inates, we are able to show that the recoverability of limitation redu ces to the solvability of a reconstruction equation under the feasibil ity 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 analy sis of recoverability of hardware limitations. The method has the feat ure that no task motion error is induced by the hardware limitations w hile minimizing a possible null motion error under the recoverability assumed.