This paper presents an improved method based on the jacobian matrix and the error feedback. By using this method, the accuracy of the solution of inverse kinematics for the vehicle-manipulator system is improved. In addition, one of the advantages of a redundant system is exploited to avoid impact on joint limitations. Numerical simulations in software Matlab are carried out to verify the efficiencies of the proposed method. | Vietnam Journal of Mechanics, VAST, Vol. 34, No. 2 (2012), pp. 79 – 90 ON THE INVERSE KINEMATICS OF AN UNDERWATER VEHICLE - MANIPULATOR SYSTEM Nguyen Quang Hoang Hanoi University of Science and Technology, Vietnam Abstract. The inverse kinematics plays an important role in the trajectory planning and the control of underwater vehicle-manipulator system. The solutions of this problem have an important influence on the motion quality of end-effectors. This paper presents an improved method based on the jacobian matrix and the error feedback. By using this method, the accuracy of the solution of inverse kinematics for the vehicle-manipulator system is improved. In addition, one of the advantages of a redundant system is exploited to avoid impact on joint limitations. Numerical simulations in software Matlab are carried out to verify the efficiencies of the proposed method. Key words: Vehicle-manipulator system, inverse kinematics, numerical simulation. 1. INTRODUCTION Nowadays, underwater remotely operated vehicles (ROV) equipped with manipulators have been applied in many areas, such as ocean research and monitoring, checking and maintaining underwater structure in offshore industries [15]. The usefullnes of an on - board manipulalaror in applications of underwater vehicle has made the vehiclemanipulator mechanism very popular in recent years and attracted several researchers [2, 12]. Normally, the vehicle - manipulator system is redundant, because it has a number degree of freedom (DOF) being relatively larger than the DOF of the end - effector. The number DOFs are the same as those of the manipulator. If the motion of the vehicle and the manipulator are controlled independently, so the advantage of the redundancy of the system is not be exploited. The motion of the end - effector depends on those of the vehicle and the manipulator, or system configurations changed to time. In order to keep the end-effector along a desired trajectory, the problem of kinematics is
