The technology of hydrodynamic modeling and marine craft motion control systems has progressed greatly in recent years. This timely survey includes the latest tools for analysis and design of advanced guidance, navigation and control systems and presents new material on underwater vehicles and surface vessels. Each section presents numerous case studies and applications, providing a practical understanding of how model-based motion control systems are designed.

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Handbook of Marine Craft Hydrodynamics and Motion Control: Fossen/Handbook of Marine Craft Hydrodynamics and Motion Control

SUMMARY An adaptive control scheme for a two-degree-of-freedom vehicle model with active suspension is proposed. The performance goal is to minimize the variance of vehicle body acceleration under inequality constraints imposed on the variance of either tire or suspension deflection. An active suspension is adapted to the changes in vehicle velocity and the type of road (or terrain) surface which is assumed to be reconstructable from the accelerometer measurements. The control gain factors are obtained by the iterative method taking advantage of stochastic linear control theory. The performance of the system is evaluated and compared to that of an active system with constant gain factors and a passive system with adjustable parameters.

Adaptive Control of Vehicle Suspension

This paper deals with tanker steering control based on a novel multiple-input multiple-output generalized ellipsoidal-basis-function-based fuzzy neural network (GEBF-FNN) with online updating of system structure and parameters. The main contributions of this paper are as follows. 1) A GEBF-FNN-based nonlinear steering model incorporating the nonlinearity underlying tanker dynamics is proposed. 2) The static local controller (SLC), whose controller gains are locally fixed with the initial forward speed and the desired heading for individual steering commands, is implemented. 3) The dynamic local controller (DLC) is further realized by employing adaptive controller gains pertaining to time-varying forward speed and heading dynamics. 4) The GEBF-FNN-based steering controller is developed by identifying a nonlinear mapping from the heading error, acceleration and forward speed to dynamic controller gains, and thereby contributing to a model-free adaptive control scheme. Simulation results and comprehensive studies on benchmark problems demonstrate that the GEBF-FNN-based model can capture the essential tanker dynamics, and the proposed SLC, DLC, and GEBF-FNN-based schemes achieve superior performance in terms of heading regulation and forward speed loss. In comparison with the SLC and traditional fuzzy controllers, the DLC and GEBF-FNN-based controllers achieve higher accuracy of heading regulation with less rudder efforts and minimal forward speed losses.

Dynamic Tanker Steering Control Using Generalized Ellipsoidal-Basis-Function-Based Fuzzy Neural Networks

This paper investigates a scheme to reject the unknown bounded time varying external disturbance for a ship course keeping control system. A mathematical model of a steering system is derived considering nonlinear features that could affect the control design process. The feedback linearization approach is adopted to simplify the nonlinear system. The adaptive sliding mode control algorithm and nonlinear disturbance observer method are developed for course keeping maneuvers in vessel steering and for providing robust performance for the environment disturbance and rudder dynamics. Furthermore, the overall stability conditions of the presented controllers are analyzed by Lyapunov’s direct method. Finally, the effectiveness of the controllers is illustrated by the simulation results on a navy vessel with twin rudders.

Ship Adaptive Course Keeping Control With Nonlinear Disturbance Observer

This note states necessary, and sufficient conditions for the existence of a linear state feedback controller such that a second-order bilinear system has a globally asymptotically stable closed loop. A suitable controller is constructed for each system which satisfies the conditions.

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Stabilizability of second-order bilinear systems

The problem of automatic steering control of a large tanker in a seaway is formulated within the framework of linear quadratic Gaussian (LQG) control theory. Wave disturbances are characterized by shaping filters, and Kalman filters are designed using these disturbance noise models. LQG controllers are designed to minimize a performance criterion commonly thought to be representative of propulsion losses due to steering. Performance of the controllers is determined by simulation results, which apply for deep water and are based on data from scale model tests.

The use of wave filter design in Kalman filter state estimation of the automatic steering problem of a tanker in a seaway

Linear quadratic (LQ) optimal control theory is applied to the design of the steering controller of a supertanker. A form of performance criterion commonly thought to be representative of propulsion losses related to steering is used as a basis for the design of controllers for course-keeping in the open-seas, for the ship in the full-load and ballast conditions at normal operating speed. The dynamics of the system are based on the use of locally linear models of the ship/steering system around an operating condition, deriving from hydrodynamic data from scale model tests. The effect of variation of the relative weightings in the performance criterion on controller performance when subjected to the seaway environment is examined using sensitivity analyses and simulation studies. The results suggest that it is possible to effect substantial propulsion savings without sacrifice in controllability using LQ techniques. It appears that linear regulator design offers a strong option to existing autopilots and more recently proposed adaptive control systems for ships of this type.

Design of the steering controller of a supertanker using linear quadratic control theory: A feasibility study

The problem of minimizing energy loss in automatic steering of ships is considered. Two ship types are analyzed-a high-speed containership and a large oil tanker. Making use of the sufficiency conditions for existence of a stable closed-loop system, it is shown that there is no theoretical difficulty in using an exact performance criterion for energy losses due to steering with an indefinite form, rather than an approximate criterion which fits the positive semidefiniteness condition of standard linear regulator (LR) theory.

An optimal controller arising from minimization of a quadratic performance criterion of indefinite form

The problem of minimizing energy loss in automatic steering of ships is considered. Two ship types are analyzed--a high speed containership, and a large oil tanker. Making use of the sufficiency conditions for existence of a stable closed-loop system it is shown that there is no theoretical difficulty in using an exact performance criterion for energy losses due to steering with an indefinite form, rather than an approximate criterion which fits the positive semidefiniteness condition of standard regulator theory.

Linear quadratic (LQ) optimal control theory is applied to the design of the steering controller of a supertanker. A form of performance criterion Commonly thought to be representative of propulsion losses related to steering is used as a basis for the design of controllers for course-keeping in the open-seas, for the ship in the full-load and ballast conditions at normal operating speed. The dynamics of system are based on the use of locally linear models of the shi p/steering system around an operating condition, deriving from hydrodynamic data from scale model tests. The effect of variation of the relative weightings in the performance criterion on controller performance when subjected to the seaway environment is examined using sensitivity analyses and simulation studies. The results suggest that

B. C. Mears

Papers

The use of wave filter design in Kalman filter state estimation of the automatic steering problem of a tanker in a seaway

Design of the steering controller of a supertanker using linear quadratic control theory: A feasibility study

An optimal controller arising from minimization of a quadratic performance criterion of indefinite form

An optimal controller arising from minimization of a quadratic performance criterion of indefinite form

Linear quadratic control theory: a feasibility study