Research On Design And Control Of 2D Digital Buffering Valve

Hydraulic valve is widely used in hydraulic system for aerospace,shipping and vehicle.Along with the rapid growth of hydraulic technique,electronic technique and control technique,electro-hydraulic valve,such as electro-hydraulic proportional valve,digital valve and electro-hydraulic servo valve,are widely used in shipping deck machinery and hydraulic steering engine.The excellent performance of electro-hydraulic valve improved the stability of shipping hydraulic system and the operation performance of the ship.In particular,its application in oil pressure control of clutches in ship propulsion unit or in vehicle transmissions also has excellent performance.With the development of the clutch towards high-power,high stability,intelligent,the traditional hydraulic buffering valve,which control the oil pressure of clutches,has poor adaptability and stability.It’s difficult to meet the requirements.Therefor this paper presents a new structure of the buffering valve.This paper uses the current mature 2D digital technique in oil pressure control of clutches,and 2D digital buffering valve is designed.The primary contents for this paper are as follows.(1)Under the application background of the hydraulic buffering valve,the oil pressure control index of clutch is summarized.The structure of the traditional buffering valve which used in an existing transmission is introduced,and the work principle of the buffering valve is analysed.And its simulation model is established based on AMESim.The buffering pressure characteristics of the traditional buffering valve is tested,and the results show that the traditional buffering valve ’s overshoot reach 117.4%at the start of buffering,and the final output pressure is oscillating.(2)For the existing buffering valves’ weakness,like extra large overshoot,poor stability,weak adaptability,2D digital buffering valve is designed by using 2D digital technology,the main structure of which is designed and calculated.And the optimum design is carried out by design of experiments(DOE).After optimization,compared with the existing traditional buffering valve,2D digital buffering valve reduces the volume of 69.77%,the power weight ratio increased by 54.6%(3)In order to enhance the controlling precision and stability of 2D digital buffering valve,control algorithm of valve output pressure characteristics is researched.Based on the mathematical model of 2D digital buffering valve,adopted PID controlling algorithm carry on the theory analysis.The simulation results show that the response time of 2D digital buffer valve is about 52 ms,and the valve overshoot is only 20.6%under the PID algorithm,but 3.5 oscillations are required,while the overshoot is only 10%through the BP algorithm,and the oscillation is only 1.5.(4)The controller of 2D digital buffering valve is developed and an experimental platform is set up for experimental study.The effects of PID algorithm on the valve output pressure characteristics are studied.The results show that the valve output overshoot under the BP algorithm is only 8%and the number of oscillations is reduced to only 1 times.Compared with the existing proportional buffering valve,the 2D digital buffering valve reduces the output overshoot from 105%to 31.2%.Finally,the buffering pressure characteristics of 2D digital buffering valve in a loaded hydraulic system are studied.