|Robust Fuzzy Controller Design for Dynamic Positioning System of Ships
Werneld Egno Ngongi*, Jialu Du, and Rui Wang
International Journal of Control, Automation, and Systems, vol. 13, no. 5, pp.1294-1305, 2015
Abstract : This paper presents a robust fuzzy controller design approach for dynamic positioning (DP) system of ships using optimal H∞ control techniques. The H∞ control technique is used to exterminate the effects of environmental disturbances. Firstly, a Takagi-Sugeno (TS) fuzzy model is applied to approximate the nonlinear DP system. Next, linear matrix inequality (LMI) and general eigenvalue problem (GEVP) methods are employed to find a positive definite matrix and controller gains. The stability of the controller is proven by using Lyapunov stability theorems. A positive definite matrix is determined by solving LMI equations using robust control toolbox available in MATLAB. The obtained positive definite matrix proves that the designed fuzzy controller is stable. Finally, a uniformly ultimately bound (UUB) and control performance for the dynamic position system is guaranteed. Simulation is carried out, and results are presented to validate the effectiveness and performance of the proposed control system.
Keyword : Dynamic positioning, eigenvalue problem, linear matrix inequality, robust fuzzy controller, Takagi-Sugeno fuzzy model, uniformly ultimately bound