Comprehensive underwater vehicle-manipulator system teleoperation

In this work, a novel comprehensive scheme for the coordinated control of remotely operated vehicle-manipulator systems (ROVMs) is proposed. In the proposed scheme, instead of commanding the motion of the vehicle and the manipulator separately, a human pilot commands only the manipulator´s end-effector motion using a parallel- architectured six-degree-of-freedom (6-DOF) joystick. The generated reference motion is then converted into a set of desired ROV and manipulator joint motion by means of using a redundancy resolution scheme that provides the means to utilize redundant degrees of freedom to accomplish secondary objectives. The redundancy resolver uses the Gradient Projection Method combined with a Mamdani-based fuzzy determination of the hierarchy of the secondary objectives. The controller relies on a unified dynamic model of the system. The quasi-Lagrange method is used to derive the equations of motion in terms of the ROV body-fixed frame. For the control problem, a sliding-mode based controller is used that contains an adaptive term for the estimation of the upper bound on the lumped uncertainty vector. The hardware-in-the-loop simulation studies illustrate that detailed subsea tasks can be completed with a small, low-cost ROVM system using the proposed ROVM operation scheme.