Title: Linear fuzzy controller design for dynamic positioning system of surface ships

Authors: Werneld Ngongi; Jialu Du

Addresses: School of Information Science and Technology, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, Liaoning Province, China ' School of Information Science and Technology, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, Liaoning Province, China

Abstract: This paper presents a linear fuzzy controller design for dynamic positioning (DP) system of surface ships using optimal H^∞ control techniques. The control technique is used to exterminate the effects of environmental disturbances. First, a Takagi-Sugeno (TS) fuzzy model is used to approximate the nonlinear DP system. Then, linear matrix inequality (LMI) and eigenvalue problem (EVP) methods are employed to solve the robust fuzzy control problem. We use the Lyapunov stability theory to prove the stability of the controller. 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 fuzzy controller is stable. Finally, a uniformly ultimately bound (UUB) and control performance is guaranteed. Simulation is carried out, and results are presented to validate the effectiveness and performance of the proposed control system.

Keywords: linear control; fuzzy control; controller design; dynamic positioning systems; H-infinity control; Takagi-Sugeno model; T-S model; fuzzy modelling; LMI; linear matrix inequalities; eigenvalue problem; Lyapunov stability theorems; UUB; uniformly ultimately bound; simulation.

DOI: 10.1504/IJISTA.2015.072215

International Journal of Intelligent Systems Technologies and Applications, 2015 Vol.14 No.1, pp.1 - 26

Received: 12 Jun 2014
Accepted: 20 Apr 2015
Published online: 05 Oct 2015 *

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