IEEE ICMA 2007 Conference
Plenary Talk 5

Design Practice of Ship Fin Stabilizers and Applying Techniques of Ship Motion Control

Hongzhang Jin
Chair Professor
Harbin Engineering University
Harbin, China 150001
Tel:86-451-82519954, Fax:86-451-82519954, E-mail:jinhz@hrbeu.edu.cn

Nowadays more and more ship motion control systems are applied in various ships. Among ship motions, roll motion causes serious damages to the equipments of ship and its performance, many efforts have been made to invent or create some equipment to weaken these bad effects. However, few types of equipment have had the same impact on roll stabilization as the active fin stabilizers.

In recent years much research has been conducted to improve the fin stabilization systems. Some results on fin stabilizers have been obtained by analyzing the classical roll motion model. In particular, based on this classic motion model, recently we have investigated issues of dynamics lift of ship fin stabilizers by using towing tank test results of fin model.

As ship roll parameters have heavy uncertainties, we must deal with them in fin stabilizer designs. In fact the biggest difficulty in the design is how to deal with the uncertainties. Some control theories, such as adaptive control and robust control, are used to solve the problem and achieved success in some control systems. But they can not deal with uncertainties of ship stabilizer control well. The difficulty of uncertainties existed in fin stabilizer design also happed in other ship motion control system designs. Some new opinions about design methods of fin stabilizer and ship motion control are proposed.

To improve the performance of the fin stabilizers, lift feedback fin stabilizers are then designed. In this talk, we analyze defects of angle feedback fin stabilizer caused by the hydrodynamic coefficient and show the control principle of the lift feedback fin stabilizer system. Because the lift is measured directly for the lift feedback fin stabilizer, the error caused by the hydrodynamic coefficient in calculating the lift can be avoided. The error found in the former research is amended and a new structure of the system is presented that can be applied in engineering. The main technical difficulties, such as lift sensor and signal processing, have been studied.

It is well known that fin motions are essentially nonlinear with many nonlinear uncertain factors. The classical linear model is only an approximate model which omits some nonlinear uncertain factors to easily calculate lift coefficients of the fins. In fact, since the linear relationship between lift of the fin and the fin angle is obtained by the static hydrodynamic experiment, some redundant errors are inevitable compared with the dynamic hydrodynamic experiments. We give restoring roll moment for the ship obtained by hydrodynamic experiment and control compensation control of two pair of fins.

To overcome the uncertainties in the system an intelligent PID controller is investigated. The application of the controller in fin stabilizer is effective to stabilize the ship because the ship model uncertainties are taken into consideration. All the results and data obtained in this talk are experimented in the towing tank and fin stabilizer test tables, therefore there have actual significance.

Hongzhang Jin is the chair professor of Control Theory and Control Engineering, in the Automation College, Harbin Engineering University. He also holds the Guest Professorship Chair in the Dalian Maritime University. He graduated from Navy Engineering Department, Harbin Engineering Institute then joined the faculty of the Department of Automation at Harbin Shipbuilding Engineering Institute in 1970. He was a visiting scholar at University of Strathclyde, UK in 1986-1987. He served as a professor, then the chair professor of Control Theory and Control Engineering in the Automation College, Harbin Engineering University from 1994 and from 2000. He also served as the Academic Committee Director of Ship Control Engineering Laboratory from 2003. At Harbin Engineering University, he teaches courses in ship control engineering, computer control and robust control. He has being engaged in ship motion control research for 40 years and designed 20 types fin stabilizers which were equipped in more than 200 different ships home and abroad. His current research interests are ship control theory and engineering, complex control system theory, and industry control systems. He has published more than 120 papers in archival journals and refereed conference proceedings, also published 5 books on ship control theory and engineering. He received the Award of Expert of Chinese Government Special Allowance(1994), the CSSC Outstanding Expert Award(1996), the National Sci-Tech Conference Award(1978), the National Sci-Tech Progress Award(II)(1985), the National Sci-Tech Progress Award(III)(1991), and other 5 Sci-Tech Awards from Commission of Science Technology and Industry for National Defense, and Heilongjiang Province. He served as Technical Editors of the Navy Electronic Technology Journal, Navy Science and Technology Journal, and Applied Technology Journal. He is a Senior Member, and the vice director of Reliability Engineering of Chinese Society of Marine Engineering and Navy Architect.