Meng Lingwei

Research on a fuzzy immune PID controller to reduce roll of near-water-surface vehicle with active bionic fin stabilizer

Near-surface vehicel will invectively roll, pitch and heave heavily when they close to surface where there are waves, sea wind and ocean current. These disturbances influenced the normal working and safety of the autonomous underwater vehicles a lot. As anti-roll technology develops, a kind of active bionic fin stabilizer which can reduce roll effectively comes out. Hence this kind of active stabilization system has a lot of uncertainties, A fuzzy-immune PID controller is proposed to optimize parameters of PID controller under different wave disturbance. From simulation results, it can be seen that this kind of PID controller can optimize system effectively.

Trajectory tracking for underactuated UUV using terminal sliding mode control

The trajectory tracking problem of an underactuated unmanned underwater vehicle (UUV) is addressed. A robust nonlinear controller is developed by using terminal sliding mode control (TSMC), which can exponentially drive an UUV onto a predefined trajectory at a constant forward speed. The kinematic controller is expanded to cope with vehicle dynamics by resorting to introduce two terminal sliding surfaces. Robustness to parameter perturbation is addressed by incorporating the reaching laws associated with the upper bound of the parameter perturbation. The proposed control law can guarantee that all error signals globally exponentially converge to the origin. Finally, a series of numerical simulation results are added to illustrate the robustness and effectiveness of the proposed control scheme.

Adaptive sliding mode control of AUV to optimize the voyage

Energy is usually the most limiting resource on activity of AUVs. It is urgent to minimize the resistance caused by the AUV motion so as to diminish the propulsion energy consumption, when AUV sails near the water surface. In this paper, to optimize the energy consumption, the dynamic resistance mathematical model of AUV, which states the relationship between the resistance and the motion/velocity of AUV, is built. An adaptive sliding mode controller with PID tuning method is presented for above problem. Moreover, in order to achieve system robustness against parameter variations and external disturbances, suitable PID control gain parameters can be systematically on-line computed based on the proposed adaptive law. The asymptotic stability property can be guaranteed according to the Lyapunov stability theorem. As a result, not only the pitch angle of the AUV is decreased by the adaptive sliding mode control method efficiently, but also the resistance caused by the pitch motion. Simulation analysis verifies the correctness of the dynamic resistance model and proposed control method.

Investigation of thrust and load characteristics of AUV propeller under the condition of different angle incoming flow

Under the influence of the sea current, the hydrodynamic performance of the propeller varies with the changing of the incoming flow direction. Aiming to obtain the hydrodynamic performance accurately, the thrust and load characteristic of AUV propeller is investigated under the conditions that different angles incoming flow go through the plane of propeller. First, the visual-physical model is built and gridded in the CFD software. The open water hydrodynamic performance of propeller is calculated in the CFD software, based on the standard turbulent model. The consistency between the calculated results and the experimental/theoretical results shows the practicability and validity of the CFD method. Then, the incoming flow angle range is set from 0° to 25°. The thrust force and load torque of propeller is calculated in the CFD software under the condition of steady incoming flow velocity but different incoming flow angle. Lastly, we can see that the propulsion force and torque of propeller will increase with the increasing of the incoming flow angle, where the maximum value would increase 75% compared with the initial case based on the analysis of the calculated results. This hydrodynamic performance is proposed for the design of the AUV propulsion control strategy. And this computed results could be the reference index when choose the rated power of the propulsion motor.