benefit to the development of the high pressure pneumatic system．The research work is
，the history and current researches on hilgh-pressure valve ofnationally and
internationally are summarized．The origination and significance of this project are
introduced．The main research objects are proposed in this chapter,ang the major
difficulties ofthis project are summarized．
In chapter 2
，a new type pneumatic proportional high-pressure valve is introduced．
Details of its structure characteristics and mechanics are described．In the pilot valve，a
proportional electro—magnet is used as pilot control component
，and the control strategy of
electric closed—loop feedback is adopted． Such a structure as pilot valve’S series
air—resistances jS a special character of this valve． We analyze the factors that affect the
valve’s performances and point out that performances ofproportional electro-magnet，volume
of control chamber,area of pilot through-flow and diameter of pneumatic plunger’S orifice
are the major factors which determine 0n the valve’3 performances．
In chapter 3
，a nonlinear mathematical model of the valve is built up to analyze the
influence of the structural parameters and controller parameters Oil the valvelS dynamic
characteristics．Based on the mathematical model
，the state equations of this valve are got．
And get an open—loop transfer function by liberalized．As a result，system’S dynamical
performances are related to the valve’S structural parameters
，the performance ofproportional
electro—magnet
，the input pressure，the ouWut pressure
，working temperature and the main
valve’S spool’S velocity．
In chapter 4
，Matlab’S tools box Simulink is used tO analyze the valve’S performances．
According tO practical experimental conditions
，input pressure is set at t5MPa，As a result
，
volume of control chamber and diameter of pneumatic plunger’S orifice have great effec!on
折江大學(xué)壩士學(xué)位論文
system’S dynamical performances．And the influence of the pilot valve’S leakage On the
performance of pneumatic pressure proportional valve is analyzed under the condition of the
input pressure 3 1．5MPa
，A method of using different widths of two throale windows is
proposed，which improves the working condition of pilot valve and reduces the influence of
pilot’S leakage
In chapter 5
，the experimental system of high—pressure proportional valve is introduced．
’Fhe dynamical characteristic
，discharge characteristic and pressure characteristic ofthis valve
are tested under the input pressure of 14MPa condition．As a result．this valve’S output
pressure ranges from 1MPa to 12MPa，when input pressure is 14MPa．And the control
performance is robust when the loads changed from 49／s to 1 209／s．The results．justify the
simulation about valve’S performances．Fixed parameters of PI controller can’t meet the
needs of control both in high output pressure and low output pressure．Volume of control
chamber and diameter of pneumatic plunger’S orifice have a great effect on system’S
dynamical performances．
In chapter 6
，the research work is summarized and perspectives on the future are
presented．
Key words：High-pressure，Pneumatic
，Proportional valve
，Mathematic model，Simulation
，
Series air-resistances
，Experimental research
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