Yang Yan-sheng

Adaptive robust dissipative designs on straight path control for underactuated ships

Abstract An adaptive robust control algorithm for ship straight path control system in the presence of both modeling uncertainties and the bounded disturbances is proposed. Motivated by the backstepping approach, the algorithm is developed by using the dissipation theory, such that the resulting closed-loop system is both strictly dissipative and asymptotically adaptively stable for all admissible uncertainties. Also, it is able to steer an underactuated ship along a prescribed straight path with ultimate bounds under external disturbances induced by wave, wind and ocean current. When there are no disturbances, the straight path control can be implemented in a locally asymptotically stable manner. Simulation results on an ocean-going training ship ‘YULONG’ are presented to validate the effectiveness of the algorithm.

An H/sub /spl infin// fuzzy controller design via T-S fuzzy model and its application to hydrofoil catamaran

A less conservative LMI-based fuzzy H/sub /spl infin// controller via T-S (Tagaki-Sugeno) fuzzy model is proposed, and applied to attitude control for hydrofoil catamaran throughout its entire operating range. Firstly, a nonlinear system is represented by a T-S fuzzy model. Fuzzy robust control strategy is secondly presented with guaranteed H/sub /spl infin// control performance, which takes into consideration a much closer relationship between subsystems. In this method, the so-called PDC (parallel-distributed compensation) scheme is used to construct the H/sub /spl infin// fuzzy controller. Finally, based on hydrofoil catamaran, HB200B-A1, simulation researches demonstrate that the effectiveness of the H/sub /spl infin// fuzzy controller for attitude control of hydrofoil catamaran is used to attenuate external disturbances, such as waves and winds. It is shown that the drawback of conventional controller for hydrofoil catamaran can be overcome successfully, which is only efficient near the operating point.

Output feedback adaptive robust control algorithm applied to ship steering autopilot with uncertain nonlinear system

A state feedback adaptive robust control algorithm is first presented for a ship steering autopilot with uncertain nonlinear system based on known parameter bound of the system and known bound of input disturbance by use of the theory of Lyapunov stability. Owing to not all states of ship motion being achieved and only ship course able to be measured on board, a high-gain observer is proposed to estimate the states of ship motion and then an output feedback adaptive robust control algorithm is developed. An example illustrating the method described is included for an ocean going training ship which belongs to our university. It is shown that the controller can make the designed system guarantee the satisfied performance by simulation based on the Matlab Simulink package.

Variable structure adaptive robust fuzzy control for a class of uncertain. nonlinear systems

The stabilization of a class of uncertain nonlinear systems within the system complication formulation function and unknown control gain parameters is investigated. A fuzzy system is employed to approximate the system complication formulation function, then the fuzzy system is used as the upper bound of uncertainty, and a variable structure fuzzy adaptive robust control that can evaluate the bound parameter of uncertainty and input control gain online is presented. An example demonstrating the method described is included for ship roll stabilization using fin control system. It is shown that the designed system guarantees the performance of robustness with respect to the perturbations and uncertainties.