TEST METHOD OF HIGH-SPEED ON-OFF VALVE DYNAMIC CHARACTERISTICS

According to the valve port features of high speed on-off valve and its actions, the valve port can be simplified into an a-type half bridge construction. A method that tests the dynamic characteristics of the high speed on-off valve by the output pressure signal of the a-type half bridge is proposed. Having analyzed the factors related to the dynamic characteristics of an a-type half bridge, a rule for designing the outlet chamber＇s volume is worked out. According to the rule, a test stand is built to test the self-developed high-speed on-off valve. From the test results, it can be seen that with the outlet chamber＇s volume controlled by the rule the rise time of the pressure signals driven by signals with different frequencies changes very little. The test results conform to the simulation results, which nroves the correctness of the method.

Dynamic Performance of High Speed Solenoid Valve with Parallel Coils

The methods of improving the dynamic performance of high speed on/off solenoid valve include increasing the magnetic force of armature and the slew rate of coil current, decreasing the mass and stroke of moving parts. The increase of magnetic force usually leads to the decrease of current slew rate, which could increase the delay time of the dynamic response of solenoid valve. Using a high voltage to drive coil can solve this contradiction, but a high driving voltage can also lead to more cost and a decrease of safety and reliability. In this paper, a new scheme of parallel coils is investigated, in which the single coil of solenoid is replaced by parallel coils with same ampere turns. Based on the mathematic model of high speed solenoid valve, the theoretical formula for the delay time of solenoid valve is deduced. Both the theoretical analysis and the dynamic simulation show that the effect of dividing a single coil into N parallel sub-coils is close to that of driving the single coil with N times of the original driving voltage as far as the delay time of solenoid valve is concerned. A specific test bench is designed to measure the dynamic performance of high speed on/off solenoid valve. The experimental results also prove that both the delay time and switching time of the solenoid valves can be decreased greatly by adopting the parallel coil scheme. This research presents a simple and practical method to improve the dynamic performance of high speed on/off solenoid valve.

High Speed On/Off Valve Control Hydraulic Propeller

The work-class remotely-operated-underwater-vehicles（ROVs） are mainly driven by hydraulic propulsion system,and the effeciency of hydraulic propulsion system is an important performance index of ROVs.However,the efficiency of traditional hydraulic propulsion system controlled by throttle valves is too low.Therefore,in this paper,for small and medium ROVs,a novel propulsion system with higher efficiency based on high speed on/off valve control hydraulic propeller is proposed.To solve the conflict between large flow rate and high frequency response performance,a two-stage high speed on/off valve-motor unit with large flow rate and high response speed simultaneously is developed.Through theoretical analysis,an effective fluctuation control method and a novel pulse-width-pulse-frequency-modulation（PWPFM） are introduced to solve the conflict among inherently fluctuation,valve dynamic performance and system efficiency.A simulation model is established to evaluate the system performance.To prove the advantage of system in energy saving,and test the dynamic control performance of high speed on/off valve control propeller,a test setup is developed and a series of comparative experiments is completed.The smimulation and experiment results show that the two-stage high speed on/off valve has an excellent dynamic response performance,and can be used to realize high accuracy speed control.The experiment results prove that the new propulsion system has much more advantages than the traditional throttle speed regulation system in energy saving.The lowest efficiency is more than 40%.The application results on a ROV indicate that the high speed on/off valve control propeller system has good dynamic and steady-state control performances.Its transient time is only about 1 s-1.5 s,and steady-state error is less than 5%.Meanwhile,the speed fluctuation is small,and the smooth propeller speed control effect is obtained.On the premise of good propeller speed control performance,the proposed high speed on/off valve control propeller can improve the effeciency of ROV propulsion system significantly,and provides another attractive ROV propulsion system choice for engineers.

OPTIMAL CONTROL OF AN ACTIVE SUSPENSION SYSTEMEMPLOYING HIGH SPEED ON/OFF SOLENOID VALVE

Previous studies have confirmed that an active suspension system with high speed ON/OFF solenoid valves could provide the same vibration isolation efficiency as that of system with pressure proportional valve. In this study, by using Linear-quadratic optimization technique and Kalman filter method, an optimal regulator controller with a state observer was designed for the proposed system. Simulation and experimental research was conducted on a quarter car model. The simulation analysis of the system frequency characteristic suggested that the peak value of magnitude response curve in the case of system with an optimal controller would be lowered significantly, and the experiment results also showed that an improvement in the vibration isolation effect was obtained in using the designed optimal controller over the sky hook damper controller.

Development of a Novel Parallel-spool Pilot Operated High-pressure Solenoid Valve with High Flow Rate and High Speed

High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously.A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system.A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design.Mathematical models of the opening process and flow rate of the valve are established.Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response.Corresponding formulas to solve 4 parts of the response time are derived.Key factors that influence the opening response time are analyzed.According to the mathematical model of the valve,a simulation of the opening process is carried out by MATLAB.Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve.Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool.The experimental results are in agreement with the simulated results,therefore the validity of the theoretical analysis is verified.Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa.The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s.According to the result of the load driving test,the valve can meet the demands of the driving system.The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

Optimal Control of Hydraulic Position System Employing High Speed On/Off Solenoid Valve

A hydraulic position system was designed employing two high speed On/Off solenoid valves with PWM(Pulse width modulation) technique and using LQ(Linear Quadratic) optimization principle. Based on the system, the parts of system can be formulated with equations. According to equations, the mathematical model of the system was established. By simulation, the corresponding LQ optimal controller was designed and the PWM signals were generated. The comparison of the simulation and experiment results show that LQ optimal control method with PWM technique employing high speed On/Off solenoid valve can provide better system performance and a high position precision is obtained.

Development of an ε-type actuator for enhancing high-speed electro-pneumatic ejector valve performance

A novel ε-type solenoid actuator is proposed to improve the dynamic response of electro-pneumatic ejector valves by reducing moving mass weight. A finite element analysis (FEA) model has been developed to describe the static and dynamic operations of the valves. Compared with a conventional E-type actuator, the proposed ε-type actuator reduced the moving mass weight by almost 65% without significant loss of solenoid force, and reduced the response time (RT) typically by 20%. Prototype valves were designed and fabricated based on the proposed ε-type actuator model. An experimental setup was also established to investigate the dynamic characteristics of valves. The experimental results of the dynamics of valves agreed well with simulations, indicating the validity of the FEA model.

Investigation into the Independent Metering Control Performance of a Twin Spools Valve with Switching Technology-controlled Pilot Stage

In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonable method to optimize system dynamic performance.Integrating these two technologies into one component can combine their advantages together.However,few works focused on it.In this paper,a twin spools valve with switching technologycontrolled pilot stage(TSVSP)is presented,which applied DHT into its pilot stage while appending IMC into its main stage.Based on this prototype valve,a series of numerical and experiment analysis of its IMC performance with both simulated load and excavator boom cylinder are carried out.Results showed fast and robust performance of pressure and flow compound control with acceptable fluctuation phenomenon caused by switching technology.Rising time of flow response in excavator cylinder can be controlled within 200 ms,meanwhile,the recovery time of rod chamber pressure under suddenly changed condition is optimized within 250 ms.IMC system based on TSVSP can improve both dynamic performance and robust characteristics of the target actuator so it is practical in valve-cylinder system and can be applied in mobile machineries.

MAGNETIC FIELD ANALYSIS OF ELECTROMAGNETIC VALVE TAKING HYSTERESIS INTO ACCOUNT

Predicting and optimizing of the high-speed solenoid on/off valve behaviorrequires an accurate model of the hysteresis loop of the magnetic material used A ferromagnetichysteresis model and a novel algorithm based on fixed-point technique to optimize theelectromagnetic model are introduced By utilizing a modified vector Preisach model of magnetichysteresis and the global genetic optimization algorithm based on partial mapping cross method, theB-H relation loops are identified accurately.

Dynamic performance and temperature rising characteristic of a high-speed on/off valve based on pre-excitation control algorithm

High speed on/off valve(HSV)is an essential component in aerospace digital hydraulic systems(ADHS).Dynamic performance and temperature rising characteristic are two important features,which determine the performance of HSV,and affect the response speed and reliability of ADHS.Increasing the driving voltage is an effective method for improving the dynamic performance of HSV.However,continuous high voltage excitation will lead to more wasted energy,higher temperature rising and lower reliability.To solve this problem,a pre-excitation control algorithm(PECA)is proposed in this paper based on the theoretical model of the influence of electrical parameters on dynamic performance and temperature rising characteristics.In PECA,an appropriate initial coil current is generated by pre-excitation instead of increasing driving voltage,which significantly shortens the switching delay time.Then,based on real-time current online calculation and feedback mechanism,the adaptive switching of five equivalent voltages is realized.Consequently,the coil current can be rapidly kept at the expected state without consuming more energy and generating more heat.Results indicate that compared with conventional PWM control algorithm,the PECA can improve dynamic performance of HSV,shorten the total switching time by 71.5%,and increase the maximum operation frequency.Therefore,the linear area of flow characteristic is expended by 80.0%,the adjusting time of HSV-controlled system is reduced by 23%,while shortening steady error by 46.7%.Moreover,the temperature rising characteristics of HSV are better,the maximum operation temperature is reduced by 68.6%,and the time to reach the steady state temperature is shortened by 20%.From the results,it can be concluded that the PECA is not only an effective and practical control algorithm for improving the performance of HSVs and HSV-controlled systems while reducing the heat generation and decreasing the temperature rising of HSV,but also can be a potential solution in ADHS.

正负脉冲电压驱动的电磁螺纹插装阀动态特性分析

提出了一种基于PWM技术的正负脉冲电压控制策略,用于提高锥阀式电磁螺纹插装阀启闭动态响应速度,使其满足数字液压技术的要求。在分析电磁螺纹插装阀结构和工作原理基础上,建立了电磁螺纹插装阀的数学模型,并在AMESim软件中搭建电磁螺纹插装阀及其测试系统的多物理场耦合建模,研究不同正负脉冲电压持续时间条件下电磁螺纹插装阀线圈电流、阀芯位移、电磁力的变化规律,确定了电磁螺纹插装阀响应速度最快时正负脉冲电压控制策略的最优控制参数。利用半实物仿真系统搭建SCV硬件在环测试实验台,对所提正负脉冲控制策略进行验证。实验表明,与常规电压控制策略相比,当正负脉冲电压控制策略中正负脉冲电压持续时间都为10 ms时,电磁螺纹插装阀的开启时间由30 ms缩短到13.5 ms,其关闭时间由139 ms缩短到14 ms。研究结果为电磁螺纹插装阀的高响应化和数字液压技术的发展提供参考。

两种直动式高速电磁阀数值模拟与动态响应对比分析

针对直动式高速电磁阀动铁芯与阀芯加工、装配工艺要求高,一致性较差的问题,提出了一种动铁芯与阀芯可分离的结构,基于AMESim平台建立此款电磁阀电–磁–机–气多物理场耦合模型,考虑了动铁芯与阀芯撞击与分离的情况,并在试验台上进行了验证。然后与另一种动铁芯与阀芯“绑定”的结构形式进行比较分析。结果表明:两种电磁阀在动态响应与影响动态响应的关键参数存在差别。在同等条件下,第一种结构形式的电磁阀动态响应整体略差,但是其对动铁芯–阀芯加工、装配工艺的要求较低。

一种比例换向阀先导级用高速开关阀运动特性分析

为研究一种用于比例换向阀先导级的高速开关阀运动特性,通过编写UDF程序控制流体力、弹簧力和电磁力共同作用下的阀芯运动;通过动网格技术实现阀的流固耦合仿真,并获取阀芯精确的运动情况以及瞬态流场的变化。结果表明:编写的UDF程序能够精确地模拟实际工作时的阀芯运动状态,获得阀的开启时间为1.8 ms。该研究方法能够获得高速开关阀精确的运动特性,为高速开关阀产品的优化提供指导。

考虑电磁铁线圈构型的高速开关阀动态特性分析

为改善高速开关阀的响应特性,以电磁铁线圈构型为切入点,对比研究了线圈构型对高速开关阀动态特性的影响规律。在建立高速开关阀数学模型以及理论分析线圈构型变化对响应时间影响的基础上,采用电磁仿真软件ANSYS Electronics,构建了高速开关阀二维瞬态仿真模型,分析了单一、叠加式、嵌套式3种线圈构型对电磁铁吸合以及高速开关阀启、闭两个动态过程的影响。仿真结果表明:在不改变其他结构参数与电气参数的情况下,与单一线圈构型相比,叠加与嵌套两种并联线圈构型能够有效缩短电磁铁空载吸合时间,减幅分别为35.1%、34.7%;叠加式线圈构型下高速开关阀的开启延迟时间缩减了4.79 ms,减幅达55.4%;嵌套式线圈构型下高速开关阀的开启延迟时间缩减了4.77 ms,减幅达55.2%。综合响应特性与能耗特性参数来看,采用叠加式线圈构型的高速开关阀具有相对更优的动态特性。该研究可为高速开关阀电磁铁的设计提供参考。

高压气动装置弹射性能分析及优化

根据高压气动弹射装置的工作原理和特点,结合实际应用给出了无缓冲腔、采用缓冲腔、采用多组高速开关阀等3种弹射装置方案,基于气体动力学理论,采用分段建模的方式,构建了内弹道方程组,计算分析了弹射装置主要参数对弹射体出筒速度、弹射过程最大瞬时过载等的影响。仿真结果表明,采用缓冲腔、采用多组高速开关阀2种方案的弹射装置均可有效降低弹射体的最大瞬时过载、提高出筒速度,且采用多组高速开关阀的效果最好。研究结果可为高压气动弹射装置的优化设计、制造与试验,提供借签。

双向复位高速开关电磁阀动态响应特性仿真研究

高速开关电磁阀作为典型的伺服液压系统执行元件,逐渐成为高精密液压系统的核心部件之一。针对双复位弹簧式高速开关电磁阀的动态响应特性开展研究,建立高速开关电磁阀的多场耦合动力学模型,系统研究了高速开关电磁阀阀芯内径、弹簧刚度、线圈线径、工作温度、控制频率及占空比等对高速开关电磁阀阀芯所受到的电磁力和阀芯运动位移的影响,得到了高速开关电磁阀的优化设计参数,为进一步研制响应速度快、性能稳定、流量及承压范围大、环境适应性强的高速开关电磁阀奠定了一定的理论基础。

高速铁路动车组主断路器转换阀射流噪声模拟分析及其降噪措施

[目的]高速铁路动车组主断路器转换阀的射流噪声非常高,严重影响了旅客的乘坐舒适性,因此有必要研究有效的降噪措施。[方法]进行了转换阀射流噪声的现场试验,测得其噪声高达96 dB,且呈现明显的间歇性与脉冲性。采用大涡模拟方法建立了转换阀射流噪声仿真数学模型,选取四种不同形状的喷口,计算得到了这四种喷口的流场速度云图。将射流流场计算结果导入LMS.Virtual.Lab软件,采用声学边界元方法模拟计算这四种喷口的射流声场,并将计算得到的四种喷口1/3倍频程频谱的模拟值与试验实测值进行对比。选取了既有的四种工业消声器,以及研发的新型结构复合材料消声器,对转换阀的降噪效果进行测试。[结果及结论]转换阀因断开主断路器而产生射流噪声。转换阀射流噪声与排气口形状密切相关,射流噪声为中高频噪声。五种消声器均能显著降低转换阀射流噪声,新型结构复合材料消声器的降噪效果最好,其降噪量可达20 dB。

高速开关阀先导驱动高水基大流量比例调速阀的设计与仿真

在智能综采工作面生产工程中,液压支架在移架和推溜的过程中经常会遭遇不稳定负载,传统开关式的电液控制元件无法对推溜油缸进行速度调控,导致推溜油缸位置控制困难,影响了刮板机的调直度,从而制约了智能综采装备的应用效率。针对这一问题,考虑到煤矿乳化液介质低黏度、润滑性差等特征,设计了一种高速开关阀作为先导阀的高水基高压大流量比例调速阀,建立了阀的数学模型,根据调速阀的内部结构及工作原理建立其AMESim仿真模型,对影响节流阀阀芯位置闭环控制特性、调速阀压差-流量特性进行仿真分析。仿真表明,A型先导液桥对主阀芯的响应具有更好的性能,主阀下控制腔容积、复位弹簧刚度对阀芯的响应速度、稳定性有一定影响。总体而言,调速阀具有较好的流量调节刚度,功能和性能达到了预期设计要求。

衔铁偏心对高速电磁阀全工况电磁力的影响

高速电磁阀(HSV)是电控燃油喷射系统的关键部件,其衔铁偏心作用是影响高速电磁阀静、动态特性的重要因素.为了揭示高速电磁阀衔铁偏心作用对其全工况电磁力的影响规律,结合试验和数值模拟方法,建立了高速电磁阀有限元仿真模型,并通过与试验电磁力对比验证了其精度,最大误差为4.8%;分析了衔铁中心偏移和偏转及其交互作用对高速电磁阀电磁力的影响.结果表明:随着衔铁中心偏移率增大,轴向电磁力逐渐变小,而径向电磁力逐渐增大,但总体对电磁力的影响不显著;随着衔铁中心偏转角增大,轴向电磁力近似呈线性下降,轴向电磁力最大降低率为59.5%,而径向电磁力虽然逐渐增大,但增幅不明显;衔铁中心偏移与绕偏移方向偏转交互作用对轴向电磁力的影响最显著,全工况下该交互因子与轴向电磁力的相关系数绝对值最小为0.471,最大为0.624.

模式切换结合模糊PWM的气动容腔压力控制方法

容腔压力是管路系统的主要控制对象,用高速开关阀代替普遍使用的比例阀进行压力调控,可大幅降低系统成本。针对单腔双阀压力跟踪系统,提出了一种模式切换结合模糊PWM的气动容腔压力控制方法。该方法的目的是减小超调,降低调节时间,提高压力跟踪性能。首先由模糊控制器根据偏差给出占空比指令,然后通过引入PWM将开关量转换为连续量调节,进而通过快速切换开关阀的工作模式实现容腔内压力的精细化调节。仿真结果表明:阶跃响应的超调量小于0.6%,峰值时间0.15 s,调节时间0.16 s,同时能够很好的跟踪上0.5 Hz的谐波信号,与当前控制策略相比,超调量和调节时间均有明显的降低。