Fuzzy Logic Approach for Hybrid Position/Force Control on Underwater Manipulator

A fuzzy logic control method for hybrid position/force control of underwater manipulator is proposed in this paper. Hybrid means both position and force control is used to regulate the motion of an underwater manipulator. The main objective of this paper is to achieve a good end-effector trajectory tracking in an underwater environment. The other goal of this paper is to control the contact force whenever the end-effector comes in contact with a compliant object. Two different values of environment stiffness are applied in this case study. The experiment was conducted via MATLAB™ simulation whereby the controller was tested using underwater environment. This includes the added mass, buoyancy and drag force. The experiment includes the performance of the manipulator tracking its trajectory when there is no object, dual object and different stiffness in the object. The result indicates that the force/position controller is able to minimize the amount of error by following the desired trajectory. The system switches into the force controller once it comes in contact with a compliant object inside its working space. 1