摘要
高压气动系统因其*的功率密度高、瞬间膨胀性大、爆发力强、温度适应范围广等特性而在、、武器装备和气动汽车等领域中得到应用。高压气动减压阀是高压气动系统的关键元件，在中的超高压自动化配气和控制中有许多需求，但目前对高压气动系统的元件和控制系统进行系统、深入研究的却很少。针对这一领域的空白和实际需求，本文对高压气动比例减压阀进行了探索性研究。研制出一种超高压气动比例减压阀，并系统分析了高压气动比例减压阀的工作机理和控制方法。论文的主要内容如下：
*章概述了国内外高压气动技术的发展状况，阐述了课题的研究意义。提出了本论文所要进行的主要工作及难点和创新之处。
第二章阐述了本课题研制的超高压气动比例减压阀的原理和结构特点。提出主阀阀芯力反馈带自密封特性的非*平衡方式和先导级采用串联气阻的滑阀式结构。对影响减压阀特性的几个关键因素进行了定性分析，指出比例电磁铁的频率响应特性、调压腔的体积、先导阀阀口通流面积和气动活塞的节流孔通径是影响减压阀特性的主要因素。
第三章深入研究减压阀的工作机理及控制性能。建立了系统的数学模型，得出系统从输入先导阀阀芯位移到系统输出压力的子系统的状态方程：并对模型进行了线性化，得出了求系统传递函数的矩阵表达式。分析表明，阀的主体结构子系统是一个极复杂的非线性系统，其性能不仅与比例电磁铁的性能和阀的结构参数有关，还与阀的输入输出压力、工作温度及主阀芯位移速度等工作状态有关。
第四章在数学模型的基础上运用Matlab的Simulink仿真工具对减压阀这一高度非线性的系统进行了仿真分析。仿真分析了在输入压力为1 5 MPa的条件下，减压阀的控制特性和主要结构参数对减压阀性能的影响。仿真分析了减压阀在高设计工作压力31．5 MPa下，先导级泄漏对于减压阀性能的影响。提出在先导级两级节流[J采用不同的节流口宽度结构的方法，大大改善先导阀的工作状况，降低先导泄漏对阀性能的影响。
第五章研制成功工作压力在10MPa以上的气动比例减压阀，并建立了超高压气动比例减压阀的实验系统。在输入压力为14 MPs．条件下对减压阀的动态性能、流量特性、压力特性及控制性能进行了实验研究。实验证明，该减压阀的设计在原理上是可行的，达到了一定的性能要求。在14 MPa的输入压力下，对于输出压力在1～12 MPa范围内具有控制能力，压力控制精度达3％以上，并且具有较好的流量特性。在6MPa下，负载流量从4 g／s变化到120 g／s，系统的控制性能稳定。实验证明了仿真对于减压阀控制性能分析的正确性，即高输出压力和低输出压力条件下的控制性能有较大差异，需要采用变增益的比例积分控制策略，也验证了仿真中对调压腔体积等参数对于减压阎性能的影响的分析。
第六章对全文进行了总结，并对后续工作进行了展望。
关键词：高压，气动，比例减压阀，数学模型，仿真，串联气阻，实验研究 ABSTRACT
High—pressure compressed air as work media that has some special advantages of
pollution free，high power density,large dispensability,strong burst force，large temperature
adaptability,and SO orl，has been applied to the aeronautics and astronautics domains，the
armament scopes and the compressed air powered vehicles aspects．However,up to no、u few
systematic and detailed researches On parts and control systems of high pressure pneumatic
have been done．
Aimed at application of the high pressure pneumatic system in the aerospace auto
distribution，principle and control methods of high pressure proportional valve are
systematically investigated，all of which have significant theoretical and practical values，
benefit to the development of the high pressure pneumatic system．The research work is
divided into the following chapters：
In chapter l，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
折江大学坝士学位论文
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
Tl |
客服1号