Closed form inverse kinematics solution for 6-DOF underwater manipulator

This paper describes modeling of the inverse kinematics of a 6-DOF underwater manipulator using closed form solution approach. The manipulator structure is based on puma560 robot with some modification. The manipulator is aimed for underwater operation in water pool. Robotic manipulator is positioning device and its end-effector is required to move in a particular way to accomplish a specific task. The major problem with manipulator is of motion or trajectory planning and its control because execution of any task needs the manipulator to follow a preplanned path. Purpose of trajectory planning is to describe the required motion of the manipulator as a time sequence of locations of joints, links and end-effector and derivatives of their locations. Inverse kinematics solutions can be divided as analytical and numerical. Analytical solutions are preferred because these yield complete computationally fast and reliable solutions. We developed a fast inverse kinematics algorithm with a closed-form solution for a 6-DOF underwater manipulator. The developed algorithm is validated using simulation in Robotic toolbox. Inverse kinematics is calculated and simulation of end effector is done for given joint and link parameters. Finally graphs for motion of manipulator as a time sequence of joints and links are obtained.