基于闭环控制的压力控制系统研究

利用S7-200PLC和拉力传感器等检测反馈元件,应用PID技术调节比例溢流阀,建立了闭环控制的轨枕预应力张拉压力控制系统,实现了对轨枕预应力张拉工序的自动控制及对持荷期间张拉力值的精确、稳定性控制.     

双工位燃油总管试验器喷嘴入口压力控制系统动态特性分析

给出了由液压泵、比例溢流阀、蓄能器、压力传感器以及节流口组成的双工位燃油总管试验器工件入口处闭环压力控制系统的原理图,建立了该系统的数学模型及Simulink仿真模型,提供了与试验器真实相符的控制参数,分析了其压力动态响应特性,并绘制了相应的响应曲线。     

比例溢流阀复合控制压力流量原理及实现

提出一种新的闭环流量控制原理和压力流量复合控制策略，适用传统控制压力的比例溢流阀既可闭环控制流量，又可取代比例溢流与比例三通调速两个阀的组合复合控制压力流量，构成的系统也最节能。研究结果表明，新原理阀的动静态性能亦非常优良。     

电液比例压力控制系统参数辨识与智能PID仿真

电液比例控制系统由于控制模型的参数无法准确获取,存在难以实现高精度、响应速度快和抗干扰能力强的控制系统的问题,本次研究采用最小二乘系统辨识法与智能PID控制相结合,有效地解决电液比例压力控制系统的难题。首先建立电液比例压力控制系统的理论模型;其次,在理论模型的基础上,根据系统单输入和单输出的实验数据,采用最小二乘系统辨识法,获得电液比例压力控制系统的传递函数;然后,根据传递函数模型,采用MATLAB软件求解非线性方程组得到系统模型参数;最后,采用智能PID控制方法,对控制系统进行仿真。仿真数据表明,本次研究成果对于工业中电液比例压力控制系统具有较好的指导作用。     

材料试验机伺服压力控制系统的模型辨识研究

介绍了材料试验机伺服压力控制系统的结构，依据面向对象的建模方法，结合材料试验机的实际结构和现场的诸多影响因素，建立了相应的数学模型。分别采用ARX和BJ两种模型结构形式，采用阶跃信号和M序列作为输入信号来进行系统辨识，获得了系统的结构参数和模型参数，分析了两种输入在两种模型结构形式时辨识的差异，从而确定适合材料试验机伺服压力控制系统的辨识方式，得到了系统的数学模型，并对所得数学模型的正确性进行了验证。     

一种深海液压系统压力补偿装置的建模与应用

设计了一种应用于深海环境的液压系统的压力补偿装置,在分析其工作原理的基础上,对压力补偿过程进行了建模与分析。结果表明,硅油补偿体积与水压成单调递增的函数关系,从而为压力补偿装置的设计提供了定量的依据。根据此设计依据研制的压力补偿装置在深海热液pH值原位探测器上得到了成功的应用,从而证明了该压力补偿装置设计方法的正确性和有效性。     

基于比例阀和伺服阀的恒减速液压站的研究

本文分介绍了液压制动系统在煤矿上的应用情况,对二级制动时减速度进行了简单的分析,并介绍了二级制动和恒减速制动的工作原理和它们的区别。简要介绍了电液比例阀和伺服阀各自的原理和区别。针对E141A液压站介绍了恒减速液压站的基本组成和主要作用,然后简要介绍了该液压站在工作制动时的电气控制原理和液压原理。最后主要介绍了安全制动的工作过程,并介绍了他的电气和液压系统的控制原理。     

基于灰色辨识的光刻机恒温控制系统建模

针对光刻机媒质远传温控系统的大惯性、多重时滞和多重扰动特点,采用理论建模与系统辨识相结合的建模方法,运用大系统解耦理论实现高阶模型的降阶分解,设计多态抗失真试验采集输出数据序列,采用系统辨识方法估计数学模型参数,建立分散时滞、扰动的温控系统动态数学模型.此模型已被成功运用于光刻机投影物镜高精度恒温控制系统中,达到了0.006℃的温度稳定度,并表现出较强的鲁棒性和自适应性.     

基于LabVIEW的气动比例阀控系统辨识

介绍了气动系统模型的辨识过程以及LabVIEW在系统辨识上的应用,并利用其辨识工具箱对气动比例阀控系统进行辨识。仿真和实验结果表明,建立的数学模型能够反映实际系统的动态特征,所提出的建模方法是可行的。     

溢流阀常见压力故障的原因及处理办法

分析了溢流阀常见压力故障的原因,并指出了各种故障的一些消除措施。     

基于电液比例溢流阀的模拟加载系统研究

针对某液压起竖设备模拟加载实验的需要,设计了基于电液比例溢流阀的模拟加载系统。介绍了系统的组成和工作原理,分析了液压缸的载荷特性。通过AMEsim软件和Matlab／Simulink软件,对模拟加载系统进行了机电液协同仿真研究。仿真结果表明,反腔压力能够较好地跟踪理论值。     

Development of a novel rotary flow control valve with an electronic actuator and a pressure compensator valve for a gas turbine engine fuel control system

This paper presents a new rotary proportional flow control valve with Cam-Nozzle configuration. The rotating cam against the fixed nozzle changes the flow area and then can meter the fuel flow. This valve equipped with a pressure compensator plunger type valve to retaining constant pressure difference across the flow control or metering valve. The cam shaft directly coupled to an electronic servomotor type rotary actuator and then it is possible to apply digital control techniques such as pulse width modulation (PWM) in this control system. This new valve configuration is developed for an electro hydro mechanical fuel control system in a gas turbine engine. In addition to aero engine application, this type of flow metering valve can widely be used in industrial hydraulic systems. In this unit, the output flow is proportional to the cam's angular position (or throttle command) and it is not sensitive to pressure fluctuations at nozzle inlet and outlet. The aim of this new design is to modify a manual single adjusted hydro-pneumatic fuel control unit to obtain a new electro-hydraulic fuel control system for a gas turbine engine. The main innovations in the presented fuel metering unit include new design of the rotary valve opening shape (Cam-Nozzle) without metal to metal contact, use of a rotary electronic actuating mechanism and also direct coupling between the actuator and the rotating cam. The increased fuel metering precision in the new flow control valve has improved the ultimate control accuracy of system. A computer simulation software based on the proposed model, is performed to predict the steady state and transient performance and to analyze effect of important design parameters on valve outlet fuel flow and obtain the final design parameters. The validity of the proposed valve configuration is assessed experimentally in the steady state and transient modes of operation. The results show good agreement between simulation and experimental in both modes (max. 4% deviation).     

A study on the improvement of the load pressure feedback mechanism of the proportional pressure control valve

The proportional pressure control valve having versatile functions and higher performance is an essential component in the open loop controlled rear wheel steering gear of the four wheel steering system on a passenger car. In this study, the authors suggest a new type of load pressure feedback mechanism which can make it easy to change the control range of load pressure without changing the capacity of solenoid. The concept of the suggested mechanism, composed of the pressure chamber with throttles in series, was described. The mathematical model was derived from the rear wheel steering gear system consisting of a valve and a cylinder for the purpose of analyzing the valve characteristics. And the programme for computing the characteristic of the valve was developed. Experiments were carried out to confirm the performance of the valve and computations were performed to ascertain the usefulness of the developed programme. The results from the computations fairly coincide with those from the experiments. The results from the experiments and computations show that the performance of new valve is as good as that of the already developed one and the new valve has an advantage in the easiness in varying the control range of load pressure.     

比例阀控气动伺服系统的建模与仿真研究

介绍了比例阀控气动伺服系统的工作机理;通过对该系统元件特性的分析,推导并建立了该系统的数学模型.采用比例控制的方法,对系统进行了仿真,得到了模型在低频工作频段内的动态响应.     

电液一体化的比例伺服系统及其在密炼机上的应用

针对密炼机上顶栓运行速度慢、输出力小且精度差的问题,选用了可以使用两个输入变量的比例伺服阀系统,进行开环速度控制和闭环压力跟踪控制,而且是在主油路上直接调压。研究结果表明,电液比例伺服阀系统使得密炼机上顶栓实现了高强度、高速度、高精度以及无级调压等功能要求。     

长输管道泄压阀水力瞬变分析及瞬变工况测试

介绍了长输管道泄压阀的结构及工作原理,分析了水击产生的原因,进行了水力瞬变分析编程计算,设计了泄压阀水力瞬变测试流程。通过试验验证泄压阀对管路水力状态的影响,为泄压阀控制水击提供了理论和试验依据。     

Experimental validation of the lifetime performance of a proportional 4/3 hydraulic valve operating in water

One of the alternative hydraulic fluid is water, which is environmentally acceptable, low-cost and non-flammable. We have designed a new hydraulic test rig and a new water proportional control valve to investigate the tribological and hydraulic behaviour of such water-based systems under pressures of up to 16 MPa and flows of up to 30 lpm. In this work, we present the lifetime performance of all-stainless-steel valve with distilled water being used as the hydraulic fluid. The results show that the water-based valve can operate for more than 10 million cycles under industrial relevant conditions if the water cleanness is appropriately maintained.     

Pressure control of hydraulic servo system using proportional control valve

The purpose of this study is to develope a control scheme for the hydraulic servo system which can rapidly control the pressure in a hydraulic cylinder with very short stroke. Compared with the negligible stroke of the cylinder in the system, the flow gain of the proportional pressure control valve constituting the hydraulic servo system is relatively large and the time delay on the response of the valve is quite long. Therefore, the pressure control system, in this study tends to get unstable during operations. Considering the above mentioned characteristics of the system, a two-degree-of-freedom control scheme, composed of the I-PDD²… feedback compensator and the feedforward controller, is proposed. The reference model scheme is used in deciding the parameters of the controllers. The validity of the proposed control scheme is confirmed through the experiments.     

智能化薄膜减压阀的研究

介绍了智能化薄膜减压阀的结构、工作原理及控制程序。