INVERSE KINEMATICS OF THE UNDERWATER VEHICLE-MANIPULATOR SYSTEMS USING KINEMATIC CONSTRAINS.

This paper addresses the Underwater Vehicle-Manipulator Systems Kinematics (UVMS). Due to the vehicle degrees of freedom such systems are kinematically redundant and need to be solved using some redundancy technique. We present an approach based on introducing kinematically constraints. The approach uses the screw representation of motions and is based on the so-called Davies method to solve the kinematics of closed kinematic chains. The UVMS is described as an open-loop chain and present a virtual kinematic chain concept. This concept allows to close this chain and so, to apply the Davies method to solve the direct kinematics. The paper outlines that the Davies method constitutes a systematic way to express the joint rates of passive joints as functions of the joint rates of the actuated joints in closed kinematic chains and that, combined with the virtual chain concept, it constitutes an useful approach to solve the direct and the inverse kinematics of the UVMS. The proposed approach is compared to other redundancy resolution methods by simulations that confirm its efficienty.