Research On The Pressure Compensation For External Hydraulic Systems Of Submersible Vehicles

Submersible vehicles play an important role in ocean exploitation, state security system and so on. Hydraulic technique is widely used to control most actuating mechanism of submersible vehicles. Some of them including hydraulic actuators have to be installed on the exterior due to their special purpose. But hydraulic power source and control components of the hydraulic system, which controls their movement, are generally put inside. This layout is different from another form that the entire hydraulic system, which includes hydraulic power source, actuators and control units, of underwater vehicles and underwater construction machinery in the seawater environment. Pressure compensation for the external hydraulic system of submersible vehicles cannot adopt a traditional bladder-type pressure compensator. So it is urgent to find other solutions. Otherwise, according to the conventional handling measure, if the external hydraulic components and actuators are located into a pressure container subject to underwater pressure, it causes a series problems containing the equipment's structure more complicated, the weight heavier, a reliable dynamic & static seal, etc.Target of the project is the underwater ambient pressure compensation for the external hydraulic system of submersible vehicles. Based on analysis on a great deal of domestic-abroad materials and all kinds of pressure compensation methods of underwater hydraulic systems, a pressure compensation method of following underwater ambient pressure with a pressure compensation valve for underwater hydraulic return lines, whose hydraulic power unit is in the atmospheric circumstance, is proposed. Employing some methods combining the theoretical analysis with the computer simulation and the experimental research, the key components containing underwater ambient pressure sensing units, directly operated pressure compensation valves and pilot operated pressure compensation valve, a saving energy and anti-interference design method of the external hydraulic system of submersible vehicles based on pressure compensation valves, a redundant design and fault-tolerant control strategy assuring a high reliability of pressure compensation system are studied more systemically and profoundly. Not only there is a higher scientific value, but also there exists a certain novelty. It gives some design and experimental ideas to the further research on pressure compensation for underwater hydraulic systems with the underwater ambient pressure compensation valve.The main content of each chapter is summarized as following:In chapter 1, based on the summary of the-state-of-the-art of underwater hydraulicsystems, underwater ambient pressure compensation and the key component------pressurecompensator related to underwater hydraulic system. The meaning and feasibility of research and development of pressure compensation for the external hydraulic circuits of submersible vehicles are discussed in terms of influence that the underwater ambient pressure imposes on underwater hydraulic circuits. The research content and work of the project that will be done in the dissertation are brought forward.In chapter 2, a new pressure compensation method for the external hydraulic system of submersible vehicles, whose hydraulic power unit is in the atmospheric circumstance, is put forward, which is a pressure compensation method of following underwater ambient pressure with a pressure compensation valve for underwater hydraulic return lines. The underwater ambient pressure compensation methods for the open and closed circuits in the underwater environment are developed. Based the above mentioned, the performance requirements of underwater ambient pressure compensation units used in underwater...