Applied Research On The Electro Hydraulic Redundancy Digital Valve In Marine Hydraulic Steering Gear

Ships, including merchant ships, warships and yachts, play a prominent role in the development of our economy and society. This research, in view of existing problems in marine hydraulic steering gear systems, deals with the application of electro hydraulic redundancy digital valve in marine hydraulic steering gear system. The electro hydraulic redundancy digital valve designed in this research can function as a slide valve when the rotary valve breaks down, so as to simplify the hydraulic system and improve the reliability and security of steering gear. Besides, the development and application of electro hydraulic redundancy digital valve is of same significance to the improvement of reliability of rudders in aerospace.Chapter one expounds the great significance of simplifying hydraulic system to ensure the navigation safety of ships with limited steering gear room, such as submarines and yachts.Chapter two surveys the latest development of redundancy technology and its application situation, by referring to foreign and domestic documents and investigation, which affords the base for the improved design from electromagnetic reversing valve to hardware redundancy-based reversing valve.Chapter three offers a comprehensive study of marine hydraulic steering gear by analyzing the characteristics of steering system, rudder control system and the working condition of main hydraulic system of steering gear, and surveying the requirements of steering gear by International Convention for the Safety of Life at Sea and Rules and Regulations for the Construction and Classification of Sea-going Steel Ships.Chapter four focus on the structure improvement of traditional reversing valve. With the help of Solidworks and AutoCAD, and by using hardware redundancy-based fault-tolerant control method, a dual-redundancy reversing valve is designed and its preliminary design drawing is obtained. Also the working principle of rotary valve and slide valve, the driving characteristics of hydraulic steering gear is illustrated and analyzed in this chapter.Chapter five establishes a mathematical model for hydraulic steering gear on the basis of related parameters from real ships. Through dynamic simulation of hydraulic system realized by Simulink software package from Matlab, a dynamic model of ship steering gear system is established, which verifies the validity and effectiveness of the established mathematical model of steering gear. The step characteristics of the system, which is obtained by establishing step simulation model of redundancy valve controlled cylinder system, verifies that the redundancy valve controlled steering gear meets the speed need of rudder propeller.Chapter six offers a summary of this research, and points out contents for further research in this field and its prospect.