Adaptive Terminal-sliding-mode Combination Control for Heading and Rolling of Marine Robot Based on Energy Optimization

Near-surface motion is an important moving posture of marine robot. Because of the disturbance from wave, the robot cannot keep a certain posture and course by itself, especially under the action of high-frequency and periodic first-order wave force, the robot will inevitably make swing motions such as roll, yaw and heave. Therefore an effective controller must be applied for ensuring the normal operation and safety of marine robot. By using the decoupling method and linearization technique, the nonlinear equation of marine robot in horizontal plane can be obtained. Based on the theory of terminal sliding mode control and the principle of zero speed fin stabilizer, an adaptive controller for course keeping and roll damping is designed, which can make the system state tracking errors converge to zero in finite time. Genetic algorithm is used to optimize the controller parameters from the viewpoint of energy optimization. The simulation results show that the controller is effective and the energy consumption is reduced, thereby the control performance is enhanced when the marine robot advances near the water surface. copyright 2011 Journal of Mechanical Engineering.