Fuzzy Logic Controller for Dynamic Positioning of an Offshore Supply Vessel

2017 ◽  
Author(s):  
Kunal N. Tiwari ◽  
Parameswaran Krishnankutty
Keyword(s):  
Fuzzy Logic Controller ◽  
Fuzzy Controller ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Dynamic Positioning System ◽  
Wave Disturbances ◽  
Control Scheme ◽  
Low Pass

The purpose of this paper is to examine the performance of fuzzy controller applied to a dynamic positioning system of ship by numerical simulation. By definition, dynamic positioning system is computer controlled system which uses the active thrusters to automatically maintain the position and heading of the ship. The proposed control scheme consist of low pass filter in cascade with three proportional derivative type fuzzy controller with Mamdani type inference scheme. Feed-forward compensation decoupling scheme is employed to reduce coupling between sway and yaw. Robustness of control scheme is assessed for Cybership II in presence of wave disturbances.

Band-Stop Filter Algorithm Research Based on Nano-Displacement Positioning System

2013 ◽  
Vol 380-384 ◽  
pp. 697-700 ◽  
Author(s):  
Yue Zhou ◽  
Xiao Xiao Yao ◽  
Jin Xiang Pian ◽  
Yan Qiang Su
Keyword(s):  
Transfer Functions ◽  
Experimental Simulation ◽  
Infinite Impulse Response ◽  
Positioning System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Precision ◽  
Band Stop Filter ◽  
Low Pass ◽  
Inherent Frequency

This paper proposed the algorithms of infinite impulse response (IIR) band-stop filter and all-pass filter to eliminate the inherent frequency for piezoelectric ceramics and improve the control precision for nanodisplacement positioning system. The IIR algorithm was composed of five steps (such as the determination of normalized frequency, filter orders and transfer functions of analog low-pass filter, analog band-stop filter and digital band-stop filter). Based on the experimental simulation results on the nanodisplacement positioning platform, the butterworth band-stop filter algorithm can achieve the requested filtering effects within 10 orders .

scholarly journals Adaptive anti-disturbance control for a class of unknown pure feedback switched nonlinear systems

2021 ◽  
Author(s):  
Longsheng Chen
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Tracking Error ◽  
Average Dwell Time ◽  
Switched Nonlinear Systems ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Scheme ◽  
Low Pass ◽  
Set Up

Abstract In this study, an adaptive anti-disturbance control scheme is investigated for a class of unknown pure feedback switched nonlinear systems subjected to immeasurable states and external disturbances. Radial basis function neural networks (RBFNNs) are employed to identify the switched unknown nonlinearities, and a Butterworth low-pass filter is adopted to remove the algebraic loop problem. Subsequently, a novel switched neural state observer and a novel switched disturbance are presented via the coupled design method to estimate the immeasurable states and compounded disturbances. Then, an improved adaptive control strategy for the studied problem is designed with the help of a filtering method to eliminate the “explosion of complexity” problem, and certain compensating signals are set up to compensate for the filter errors, where switched updated laws are constructed to lessen the conservativeness caused by adoption of a common updated law for all subsystems. By utilizing the Lyapunov stability theorem, the developed control scheme can guarantee that all signals in the closed-loop system are bounded under a class of switching signals with the average dwell time (ADT), while the tracking error can converge to a small neighbourhood of origin. Finally, simulation results are provided to demonstrate the effectiveness of the presented approach.

Adaptive Fuzzy Controller Design for Dynamic Positioning System

2014 ◽  
Vol 541-542 ◽  
pp. 1256-1259
Author(s):  
Yong Sheng Zhao ◽  
Yi Ming Bai ◽  
Wen Hui Wu
Keyword(s):  
Fuzzy Controller ◽  
Controller Design ◽  
Parametric Uncertainty ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Adaptive Fuzzy Controller ◽  
Dynamic Positioning System ◽  
Adaptive Fuzzy ◽  
Adaptive Law ◽  
Backstepping Algorithm

An adaptive fuzzy controller for dynamic positioning (DP) system is designed. The controller utilizes Backstepping algorithm as the adaptive law and uses a fuzzy system for approximating the disturbances and uncertainties. The proposed adaptive fuzzy controller is proven to be uniform bounded in the sense of Lyapunov. Simulation results show that DP vessel with the adaptive fuzzy controller would be more adaptive with environmental interference and ship parametric uncertainty.

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