温度影响下的电液伺服阀故障机理分析

通过分析双喷嘴挡板式电液伺服阀的结构及工作原理,从力矩马达、前置级喷嘴挡板阀、功率级滑阀、液压油及密封件入手,深入研究各组成部分在温度影响下的特性变化及故障发生机理,为电液伺服阀的温度特性研究奠定了一定的基础。     

伺服力矩马达输出转矩影响因素分析

电液伺服阀作为液压伺服控制元件中的核心元件,能将微弱信号转换为大功率信号,力矩马达作为电液伺服阀的核心元件,其性能直接影响电液伺服阀的性能。为了分析力矩马达输出转矩的影响因素,基于AMESim搭建仿真平台对各个因素进行分析,结果表明,永磁体剩余磁化强度、衔铁中心到衔铁末段距离、气隙处磁极面积和线圈匝数对力矩马达输出转矩影响较大,永磁体的长度以及横截面积和衔铁处于中位时气隙长度对力矩马达输出转矩影响较小,并通过试验验证了其正确性。     

电液伺服阀力矩马达的综合刚度

电液伺服阀力矩马达的综合刚度直接影响电液伺服系统的动态性能。提出了利用相对频率幅值比和相对频宽的电液伺服阀力矩马达的设计概念。分析了相对频率幅值比与相对频宽、幅值裕度和相位裕度之间的关系,得出了相应关系的曲线族,并给出了基于曲线族的力矩马达优化参数设计实例,为电液伺服阀力矩马达综合刚度的优化设计提供了理论依据。     

磁流体对伺服阀力矩马达动态特性的影响

利用磁流体在外加磁场作用下具有较高饱和磁化强度和较大粘度的特点,提出了采用磁流体改善伺服阀力矩马达动态特性的方法。通过把磁流体添加到伺服阀力矩马达的工作气隙,来增加力矩马达的阻尼,改变力矩马达的动态响应特性,提高力矩马达及伺服阀的稳定性,从而有助于抑制和消除伺服阀自激振荡及噪声。通过对磁流体作用机理及力矩马达磁回路的分析,给出了磁流体作用力数学模型,以及添加磁流体和不添加磁流体的力矩马达动态数学模型,采用MATLAB/Simulink对添加磁流体和不添加磁流体的伺服阀力矩马达动态响应特性进行了分析,给出了分析结果,并通过激光位移传感器对伺服阀力矩马达动态响应特性进行了试验研究。仿真及试验结果表明,磁流体可增加伺服阀力矩马达的阻尼比,从而提高伺服阀力矩马达的稳定性和抗干扰能力。     

基于幅值裕度的电液伺服阀优化设计

分析了力反馈电液伺服阀的频宽和相位裕度与幅值裕度之间的关系,得出了电液伺服阀在不同阻尼比时的频宽比和幅值裕度关系的曲线族,相位裕度和幅值裕度关系的曲线族.给出了在电液伺服阀设计和稳定性分析时如何运用所得出的2个典型曲线族图进行力矩马达综合刚度和结构参数优化设计的方法和步骤,还进行了理论结果和仿真结果的对比分析.     

正开口阀在电液负载模拟器中的应用

从正开口阀的阀系数入手，分析其抑制电液负载模拟器多余力矩的机理。给出流量伺服阀、压力伺服阀、流量一压力伺服阀控制电液负载模拟器时阀正开口量的确定办法，并对和正开口阀有相似加载特性的加载马达两腔开连通孔进行了多余力矩抑制实验，为正开口阀用于电液负载模拟器提供了依据。     

无力矩马达电液伺服阀

本文介绍用PZT压电元件和PMN电致伸缩元件制作的无力矩马达电液伺服阀。用PMN制做的无力矩马达伺服阀可大大提高动态响应特性。     

浅析液压锁电磁场对电液伺服阀组件的影响

首先对电液伺服阀组件工作原理进行了介绍,然后在对电液伺服阀和液压锁的电磁场进行分析的基础上,探索了组合条件下液压锁的电磁场对电液伺服阀输出性能的影响。分析表明,液压锁电磁场产生磁通的大小和方向与液压锁的实际工作电压及供电极性相关,电液伺服阀力矩马达工作气隙处的原有磁通叠加后会改变衔铁的偏转力矩,最终导致伺服阀组件的输出压力变化。最后,通过改变液压锁供电电压和供电极性,进行了试验验证。     

射流管伺服阀AMESim建模与仿真

对二级力反馈射流管电液流量伺服阀的结构及工作原理进行了分析研究,利用AMESim中的基本库及元件库进行力矩马达磁路、滑阀组件的建模,利用AMESet工具进行衔铁组件及射流放大器的建模,建立射流管流量伺服阀的整阀AMESim模型,仿真结果与实际情况吻合。     

基于CNN+LSTM神经网络的电液伺服阀故障预测

针对电液伺服阀故障预测中故障类型复杂多变、早期故障较弱、时间序列难以处理等问题,构建了卷积神经网络(CNN)和长短期记忆神经网络(LSTM)相结合的电液伺服阀故障预测模型,取代人工特征选择和提取,解决故障预测的时序问题。以G761型电液伺服阀为例,利用AMESim软件对伺服阀阀芯磨损和孔板堵塞故障数据集进行了仿真,并用仿真故障数据验证了模型的预测精度。同时将LSTM,CNN,CNN+LSTM 3种模型针对电液伺服阀故障预测诊断的精度进行对比,CNN+LSTM故障预测模型训练时间更快,得到更高的预测精度,具有更好的适应性。     

基于小波故障提取的电液伺服阀故障诊断

分析了电液伺服阀故障诊断的特点,对比了几种现行的故障诊断方法,提出用小 波分析方法来构造奇异信号提取器。文中对小波在故障诊断中的重要作用进行了描 述,给出了小波提取器的结构形式,并就输入电流信号进行了仿真,与ＦＦＴ结果的 对比,显出其明显的优越性。     

Influence of magnetic reluctances of magnetic elements on servo valve torque motors

The current research of electro-hydraulic servo valves mainly focuses on the vibration, pressure oscillating and source of noise. Unfortunately, literatures relating to the study of the influence of the magnetic reluctances of the magnetic elements are rarely available. This paper aims to analyze the influence of the magnetic reluctances of the magnetic elements on torque motor. Considering these magnetic reluctances ignored in previous literatures, a new mathematical model of servo valve torque motor is developed and proposed based on the fundamental laws of electromagnetism. By using this new mathematical model and the previous models, electromagnetic torque constant and magnetic spring stiffness are evaluated for a given set of torque motor parameters. A computer simulation by using AMESim software is also performed for the same set of torque motor parameters to verify the proposed model. The theoretical results of electromagnetic torque constant and magnetic spring stiffness evaluated by the proposed model render closer agreement with the simulation results than those evaluated by the previous models. In addition, an experimental measurement of the magnetic flux densities in the air-gaps is carried out by using SFL218 servo valve torque motor. Compared with the theoretical results of the magnetic flux densities in the air-gaps evaluated by the previous models, the theoretical results evaluated by the proposed model also show better agreement with the experimental data. The proposed model shows the influence of the magnetic reluctances of the magnetic elements on the servo valve torque motor, and offers modified and analytical expressions to electromagnetic torque constant and magnetic spring stiffness. These modified and analytical expressions could provide guidance more accurately for a linear control design approach and sensitivity analysis on electro-hydraulic servo valves than the previous expressions.     

旋转直接驱动电液压力伺服阀的设计研究

旋转直接驱动电液压力伺服阀的显著特点是阀芯由有限转角力矩电机直接驱动,滑阀级输出负载压力。对该阀进行了原理分析、数学建模,并且根据数学模型进行了仿真分析,设计了控制器结构,分析了控制器中各参数对该阀性能的影响,对该阀的静态特性和动态特性进行了试验研究,试验结果与仿真结果基本一致,性能达到了目前国内其他形式压力伺服阀的水平,推动了国内力控制系统的发展。     

一种基于虚拟仪器的电液伺服阀故障诊断方法

本文提出了一种基于虚拟仪器技术和互相关原理的电液伺服阀故障诊断方法。利用在LabVIEW6.1环境下开发的软件可以对电液伺服阀的输入和输出信号进行相关分析,进而可判断出电液伺服阀是否存在故障。试验结果表明,该方法简单易行,可有效的提高电液伺服阀的故障确诊率。     

大流量2D伺服阀的研究与设计

为实现伺服阀的大流量,采用了2D阀的结构方案.2D阀利用伺服螺旋机构将阀芯的旋转运动转化为阀芯的直线运动,从而实现伺服阀的液压功率放大.采用步进电机作为电-机械转换器来驱动阀芯转动,为使阀芯获得较大的扭矩,采用了较大的传动比.设计了零位保持机构保证了伺服阀工作的稳定性和零位调节的精确性.对伺服阀的阀芯进行了力学分析,并建立了数学模型.最后利用MATLAB进行了仿真研究,仿真结果理想,符合设计要求.     

Novel torque motor model for performance design and analysis of a servo valve with permanent magnets

Servo valves are widely used for modern hydraulic actuator control. This valve consists of a torque motor with permanent magnets. In present study, a novel torque motor model is derived by considering magnetic flux leakage and demagnetization effect of the permanent magnets involved in the servo valve. The derived model was validated by comparing experimental data with the model calculation represented with physical parameters. Since these two important physical phenomena, missing in the previously well-known model, are considered in the newly derived torque motor model, it can be used for the physical parameter design of a torque motor and the analysis of a servo valve controlling electro-hydraulic servo systems.

     

基于内置传感器的大型数控机床状态监测技术

提出一种基于光栅尺、编码器、伺服进给电机电流(转矩)等内置传感器的机床状态监测系统,深入研究转矩、位置、润滑特性等内置传感器测试原理,就开放式和商业数控系统给出不同采集机床状态信息的策略;并进行多种工况下的恒速、润滑特性测试,试验分析表明电机输出转矩(电流)、位置、瞬时速度、瞬时加速度等内置传感器信息被用于机械传动部件故障诊断和伺服控制特性评估的可行性和有效性,从而为大型数控机床状态在线监测和故障快速溯源,提供技术支撑.     

基于AMESim的电液伺服系统故障仿真研究

针对液压伺服系统的机、电、液藕合特征,应用仿真软件AMESim对差动液压伺服缸系统进行建模。并对仿真模型植入故障参数,利用仿真软件计算出系统的响应,获得系统异常表现与系统元件故障之间的联系。为仿真结果能作为实际系统的故障诊断样本。实际证明该类仿真完全能够模拟实际系统的各类故障响应。     

Development of a novel two-dimensional(2D) three-way(3W) fuel flow control servo valve with constant pressure difference

To solve the problems of large volume, and low integration of traditional electro-hydraulic servo valve with constant pressure differential fuel metering device, a new two-dimensional three-way constant pressure differential fuel flow control servo valve (2D3WFFCSV) is developed. It innovatively adopts the advantages of lightweight of “two-dimensional hydraulic technology”, The constant differential pressure function and flow regulation function are integrated into a two-dimensional (2D) main spool with two degrees of freedom (rotational and axial degrees of freedom). The flow control process of 2D3WFFCSV is as follows: firstly, the armature of the torque motor and the two-dimensional piston are coaxially installed at the end of the two-dimensional piston, so the torque motor can directly drive the two-dimensional piston to rotate; secondly the “hydraulic servo screw mechanism”, which can amplify the power, is used to drive the two-dimensional piston to move in line; Finally, a pair of conversion mechanisms (roller group and spiral track conversion mechanism) are converted into the angular displacement of 2D main spool to control the area of flow valve port. The axial degree of freedom of 2D main spool realizes the function of constant differential pressure. To improve the flow control accuracy of the servo valve, the axial position of the 2D piston is detected by the linear displacement sensor (LVDT), and the signal is transmitted to the controller to realize the closed-loop control. To explore its open-loop characteristics, the mathematical models of torque motor, two-dimensional piston and main spool are established to obtain its open-loop transfer function. Then the AMESIM simulation model is built. To optimize the design of the system, through the dynamic simulation of the system, the influence of key parameters on the dynamic response of the system can be studied. An experimental study is carried out to verify the design feasibility of the servo valve. The experimental results show that under the condition of no-load and full-scale input, the closed-loop delay of the servo valve is 1.84%, the linearity is 2.14%, the step response time is 43 ms, and the dynamic frequency response is 38 Hz. The newly developed 2D3WFFCSV has the advantages of high integration, small size, light weight (801.5 g) and high response and control accuracy. It can replace the constant differential pressure, metering valve and hydraulic servo valve in the aeroengine fuel regulator.