Robust fuzzy controller design for dynamic positioning system of ships

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.

Dynamic positioning of ships based on robust fuzzy observer

“…Then, (13) is approximated via three T–S fuzzy model rules [46]. This article assumes that the environmental disturbance is unknown but with known upper‐bounded such that , of which represents a vector of unknown environmental disturbances [20].…”

“…Application of HGO in [18] offers a high capability to disturbance rejection. Many studies concerning control design for the DP system of ships have been done and presented [2–23]. Consequently, it is clear that DP systems have constantly been advancing through decades in the effort of lessening DP control snags.…”

Integrated Fault Estimation and Fault‐Tolerant Control for Dynamic Positioning of Ships

“…e dynamics of dynamic positioning ships described in (2a)-(2c) is considered, and Assumptions 1 and 2 are supposed. If the fault-tolerant controller is designed as 3 , P are the solutions of the following LMIs:…”

“…Dynamic positioning systems (DPS) can only rely on their own propulsion to counteract the interference of the external environment and maintain the ship's position and heading at the fixed location or along the predetermined track [1]. With the increasing focus on the ocean exploitation, dynamic positioning system has become an attractive research topic and has drawn great attention from control communities during the past two decades, with many results reported in the literature, such as hybrid control [2], fuzzy control [3,4], backstepping [5,6], and model predictive control [7]. e highly disturbed marine environment will lead to aging of the components of ships, which causes inevitable malfunction in actuators.…”

A Nonlinear Robust Controller Design for Ship Dynamic Positioning Based on L2-Gain Disturbance Rejection

“…But in ship motion control process, it is difficult to design ship controller due to effects of environmental disturbances such as wind, waves, current, and unmodelled dynamics. And among control methods of DP system, fuzzy control, backstepping control, neural network control, and hybrid control (see, e.g., [3][4][5][6][7][8][9][10]) are commonly used. Not depending on ship's accurate model, robust fuzzy control by using optimal ∞ control technique on DP ships was designed and had good performance in disturbance rejection and fast response and had good robustness [4].…”