AN OPTIMIZED ENERGY-EFFICIENT PATH FOLLOWING ALGORITHM FOR UNDERACTUATED MARINE SURFACE SHIP MODEL

An optimized path following guidance law is proposed for path-following of an underactuated surface ship. The main purpose of the proposed guidance law is to make a marine vessel travel with more energy efficiency. A combined feedback and feedforward controller is used for the heading control. The feedforward term is designed based on the well-known Nomoto model, whose parameters are estimated using least-square support vector regression. In order to achieve optimal operation of a marine vessel, a global optimization algorithm is employed to search the regularization factors, which are the trade-off between the total cross-track errors and total control energy. The simulation studies are carried out to demonstrate the performance of the proposed guidance law. The proposed method is an effective and practical guidance law and provide an optimal option for marine navigator.

DETERMINING ROBUST PARAMETERS IN STABILIZING SET OF BACKSTEPPING BASED NONLINEAR CONTROLLER FOR SHIP COURSE KEEPING

The authors have addressed an important topic that is needed for backstepping algorithm to guarantee the robust performance of the closed-loop system. A novel method of determining parameters was presented based on ship maneuvering empirical knowledge and closed-loop shaping theory, and theoretical proof had shown the uniformly asymptotic stability of an established nonlinear Nomoto model. However, the following important points are suggested for the improvement of this paper.

Concise Robust Control of the Nonlinear Ship in Course-Keeping Control

Most of the existing nonlinear ship course-keeping control systems are designed with the Nomoto model, which solely considers the yawing of the ship with only one Degree of Freedom (DOF), and it does not consider the coupling between the longitudinal and the lateral velocity of the ship. In this paper, a nonlinear ship course controller design method that can be used in a nonlinear coupled model was proposed. A stable nonlinear ship course controller with anti-wind and anti-wave interference was constructed based on the Lyapunov stability principle and robust control theory, which can be used in the course control of autopilot in the case of wind and waves. In this method, the coupling among the longitudinal and lateral velocity as well as yawing of the ship was considered. The simulation results showed that the method can not only effectively control the ship’s course but also can track the dynamic course effectively. At the same time, compared with the PID control method based on backstepping, the steering angle of the rudder angle of our method is smaller and the wear and tear of steering gear will be smaller.

DESIGNING SHIP COURSE MOVEMENT USING PSEUDOINVERSE MATRICES FOR MEASURING STATE VECTOR OF CONTROLLED OBJECT

To configure the control systems of the ship movement along the trajectory, it is necessary to be concerned with the parameters of its controllability. There has been proposed building a matrix model based on measurements of the state vector of a controlled object. The construction of the model is considered on the example of the problem of ship course control. An algorithm for determining the matrix coefficients of the selected model is proposed. The operation of the considered algorithm has been checked for square matrices by finding their inverse matrices, as well as for rectangular matrices for which the pseudo inverse matrix was found. The illustration of the proposed approach is carried out using the example of a simple 1-order linear Nomoto model. The considered approach is quite universal and can be applied to higher order models, including nonlinear ones.

MODEL REFERENCE ADAPTIVE CONTROL-BASED GENETIC ALGORITHM DESIGN FOR HEADING SHIP MOTION

In this paper, the heading control of a large ship is enhanced with a specific end goal, to check the unwanted impact of the waves on the actuator framework. The Nomoto model is investigated to describe the ship’s guiding progression. First and second order models are considered here. The viability of the models is examined based on the principal properties of the Nomoto model. Different controllers are proposed, these are Proportional Integral Derivative (PID), Linear Quadratic Regulator (LQR) and Model Reference Adaptive Control Genetic optimization Algorithm (MRAC-GA) for a ship heading control. The results show that the MRAC-GA controller provides the best results to satisfy the design requirements. The Matlab/Simulink tool is utilized to demonstrate the proposed arrangement in the control loop.

Ship Manoeuvring Model Parameter Identification Using Intelligent Machine Learning Method and the Beetle Antennae Search Algorithm

In order to identify more accurately and efficiently the unknown parameters of a ship motions model, a novel Nonlinear Least Squares Support Vector Machine (NLSSVM) algorithm, whose penalty factor and Radial Basis Function (RBF) kernel parameters are optimised by the Beetle Antennae Search algorithm (BAS), is proposed and investigated. Aiming at validating the accuracy and applicability of the proposed method, the method is employed to identify the linear and nonlinear parameters of the first-order nonlinear Nomoto model with training samples from numerical simulation and experimental data. Subsequently, the identified parameters are applied in predicting the ship motion. The predicted results illustrate that the new NLSSVM-BAS algorithm can be applied in identifying ship motion’s model, and the effectiveness is verified. Compared among traditional identification approaches with the proposed method, the results display that the accuracy is improved. Moreover, the robust and stability of the NLSSVM-BAS are verified by adding noise in the training sample data.

An Optimized Energy-Efficient Path Following Algorithm for Underactuated Marine Surface Ship Model

An optimized path following guidance law is proposed for path-following of an underactuated surface ship. The main purpose of the proposed guidance law is to make a marine vessel travel with more energy efficiency. A combined feedback and feedforward controller is used for the heading control. The feedforward term is designed based on the well-known Nomoto model, whose parameters are estimated using least-square support vector regression. In order to achieve optimal operation of a marine vessel, a global optimization algorithm is employed to search the regularization factors, which are the trade-off between the total cross-track errors and total control energy. The simulation studies are carried out to demonstrate the performance of the proposed guidance law. The proposed method is an effective and practical guidance law and provide an optimal option for marine navigator.

Conversion of A Second- To First-Order Linear Nomoto Model in the Light of Zigzag Manoeuvre Performance

The problem of considerable difference between the first- and second-order linear Nomoto models is undertaken, not well covered in literature so far. If the former approximates the latter (better one, of a sound hydrodynamic interpretation) for some reasons, its parameters can not be easily derived from the other one, except for some specific rare cases. For such an identification purpose, we can use a simulated zigzag response and the classic procedure proposed by Nomoto in 1960. However, the first-order model thus developed yields somehow redefined constants against the original model, which lose their normal hydrodynamic (or kinematic) sense. In other words, it is very sensitive to the manoeuvre type on input, being therein the zigzag test. Therefore, the model is allowed to be only used for simulating motions essentially similar to the input zigzag. In other words, the identification procedure works like a blind curve-fitting and the first-order model (in contrast to second-order one) is inadequate for reflecting arbitrary manoeuvres, even for mild rudder as to be within ‘linear’ assumptions.This study examines systematically and in detail such an incompatibility of the first order model in that it presents the conversion charts from the standpoint of 10°/10° zigzag test matching. One can receive higher or lower values for the parameters of first-order model, versus the second-order one, depending on the T3/T2 ratio of the latter model.

Obtaining First and Second Order Nomoto Models of a Fluvial Support Patrol using Identification Techniques

In this paper we present a method for obtaining a second order Nomoto model that describes the yaw dynamic of a Patrol River Boat. This model is obtained from experimental input and output data gathered from the turning circle maneuver. System identifications techniques and a gray box model are employed to find the coefficients of the Nomoto model. The results of the identification process as well as the results of validation process are presented