Design And Research Of Hydraulic Synchronous Control System Based On High Speed On-off Valve

The traditional hydraulic synchronous system, either the open-loop system or the close-loop system, there are some obvious disadvantages. The cost of the open-loop is low, but its control precision is also not high; the structure of the close-loop is based on servo valve or proportional valve, so not only the cost is high but also the digital control is hard to realize. The digital valve represented by high speed on-off valve, is very significant to the development of the electro-hydraulic control technology, because it possesses lots of prominent advantages such as interacting with computer conveniently and high reliability.Firstly, the thesis analyses the advantages and disadvantage of different types hydraulic synchronous control systems, then discusses the necessity and feasibility of designing the hydraulic synchronous control system based on high speed on-off valve. Secondly, the thesis puts forward five schemes of the synchronous control system, which is based on the characteristics of the high speed on-off valve. The advantages and disadvantages of different schemes are compared and illuminated. The most feasible two schemes are chosen to be studied at last. One of them is the high speed on-off valve works directly, and the other is that the high speed on-off valve works as a pilot valve. The corresponding mathematical models are established after researching on them. And the dynamic simulation of the scheme is chosen to be studied. It can prove the feasibility of this scheme is better. Lastly, in order to overcoming the problems of the system, the compound control strategy based on fuzzy self-adaptive PID is introduced. The synchronous controller is designed. It can improve the controllability of the system and offers the theoretical aegis and technological guarantee to the realization of high precision in the hydraulic synchronous control.