Fault Detection and Diagnosis of Pneumatic Control Valve Based on a Hybrid Deep Learning Model

As the growing requirements for the stability and safety of process industries,the fault detection and diagnosis of pneumatic control valves have crucial practical significance.Many of the approaches were presented in the literature to diagnose faults through the comparison of residual sequences with thresholds.In this study,a novel hybrid neural network model has been developed to address the issue of pneumatic control valve fault diagnosis.First,the feature extractor automatically extracts in-depth features of the signals through multi-scale convolutional neural networks with different kernel sizes,which not only adequately explores the local distinguishable features,but also takes into account the global features.The extracted features are then fused by the feature fusion layer to reduce redundant features.Finally,the long short-term memory for fault identification and the dense layer for fault classification.Experimental results demonstrate that the average test accuracy is above 94%and 16 out of the 19 conditions can be successfully detected in the simulated actual industrial environment.The effectiveness and practicability of the proposed method have been verified through a comparative analysis with existing intelligent fault diagnosis methods,and the results suggest that the developed model has better robustness.

Flow Control for a Two-Stage Proportional Valve with Hydraulic Position Feedback

The current research mainly focuses on the flow control for the two-stage proportional valve with hydraulic position feedback which is named as Valvistor valve.Essentially,the Valvistor valve is a proportional throttle valve and the flow fluctuates with the change of load pressure.The flow fluctuation severely restricts the application of the Valvistor valve.In this paper,a novel flow control method the Valvistor valve is provided to suppress the flow fluctuation and develop a high performance proportional flow valve.The mathematical model of this valve is established and linearized.Fuzzy proportional-integral-derivative(PID)controller is adopted in the closed-loop flow control system.The feedback is obtained by the flow inference with back-propagation neural network(BPNN)based on the spool displacement in the pilot stage and the pressure differential across the main orifice.The results show that inference with BPNN can obtain the flow data fast and accurately.With the flow control method,the flow can keep at the set point when the pressure differential across the main orifice changes.The flow control method is effective and the Valvistor valve changes from proportional throttle valve to proportional flow valve.For the developed proportional flow valve,the settling time of the flow is very short when the load pressure changes abruptly.The performances of hysteresis,linearity and bandwidth are in a high range.The linear mathematical model can be verified and the assumptions in the system modeling is reasonable.

Investigation of Semi-Active Hydro-Pneumatic Suspension for a Heavy Vehicle Based on Electro-Hydraulic Proportional Valve

Hydro-pneumatic suspension is widely used in heavy vehicles due to its nonlinear characteristics of stiffness and damping. However, the conventional passive hydro-pneumatic suspension can’t adjust parameters according to the complicated road environment of heavy vehicles to fulfill the requirements of the vehicle ride comfort. In this paper, a semi-active hydro-pneumatic suspension system based on the electro-hydraulic proportional valve control is proposed, and fuzzy control is used as the control strategy to adjust the?damping force of the semi-active hydro-pneumatic suspension. A 1/4?semi-active hydro-pneumatic suspension model is established, which is co-simulated with AMESim and MATLAB/Simulink. The co-simulation results show that the semi-active hydro-pneumatic suspension system can significantly reduce vibration of the vehicle body, and improve the suspension performance comparing with passive hydro-pneumatic suspension.

Study on Outboard Inductive Damping Valve in Hydro-pneumatic Suspension

A new outboard inductive damping valve without any electronic control system is developed. Its working principle,structure and external characteristic are studied. Its mathematical model is presented and its damping characteristic is investigated on the basis of fluid continuity equation,differential equations of motion and Bernoulli equation. The influence of the valve parameters on the damping characteristic is studied numerically. The effects of outboard inductive damping valve and common damping valve on ride and tire load are compared also. The external characteristic of the valve is verified in bench test. The results show that the valve’s mathematical model is quite accurate and the developed valve can be adjust in two stages,which can also meet the requirements of the dynamic characteristic of the vehicle suspension system.

A Kind of PWM Pneumatic Servo Control System——Modulation Methods and Dynamic Responses

Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.

Concentric Annular Clearance-Controllable Pressure Characteristics Research of a High Pressure Pneumatic Pressure Assembly

High pressure is an important development orientation in pneumatic field,since it can not only improve dynamic characteristics of pneumatic system but also decrease the size of components and mounting space.Due to the advantages of high energy density and high instant expansibility,high pressure gas has been widely used in many applications.However,systematic researches are lacked especially in pressure characteristics which are very important in pneumatic system at present.In a high pressure pneumatic system,the pressure of a fixed cavity with annular clearance needs to be controlled within a wide range,so a single stage proportional slide valve is proposed to satisfy the requirements of high pressure and low flow rate.First,working principle and structure of the pressure assembly and the slide valve are introduced.Then mathematical model of the high pressure pneumatic system is built up;controllable pressure range is simulated,and influence of uncertain factors,such as fit clearance of the pressure valve and the cavity on controllable pressure,is discussed.Finally,a test bench of the pressure assembly is built up,and the controllable pressure and step response experiments are carried out.Both simulation and experimental results show that the designed slide valve can satisfy the requirements well.The proposed clearance presumption method based on simulation and experimental results is valuable for indirect measurement of processing tolerance.

全自动气控座椅加载试验机的设计

根据目前中小企业对座椅载荷进行疲劳试验与检测的实际需求以及目前试验机的发展情况,发现了市面常见的座椅载荷试验机存在前期投资大、机构复杂及维护保养需求高等问题,在中小型座椅生产企业中推广和使用受限。基于此,从中小企业实际需求出发,本着结构简单、投资经济、便于使用的原则,提出一种全自动气控座椅载荷疲劳试验机,设计控制机构完全采用压缩空气作为驱动源,其来源方便、环保节能。在对当前座椅加载试验机特点及需求研读与分析的基础上,提出了全自动气控加载试验机的总体设计思路;根据对座椅加载控制的要求与结构模式,形成气动控制系统的总体架构及控制原理与控制方法设计;对座椅加载疲劳试验机进行了实验室模拟实验测试。结果表明,此控制系统设计方案能够实现座椅载荷负载大小变化模拟,可以实现座椅加载模拟工作节拍控制以及座椅加载时长控制调节,且完全脱离供电需求,经济环保,为生产企业后期使用维护提供了极大的方便。

基于BP神经网络的Smith-Fuzzy-PID算法在阀门定位中的应用研究

为解决气动调节阀控制过程中出现的超调大、精度低等问题,本文采用BP神经网络整定出较优的PID(Proportional Integral Derivative)控制参数,对Smith预估控制器以及模糊控制器进行设计,实现了基于BP神经网络的Smith-Fuzzy-PID控制方法。搭建了实验平台,通过阶跃响应实验来对控制方法进行验证,验证结果表明,提出的方法调节过程无超调,调节时间仅为1.9 s,定位精度在±0.5%以内,有效提高了系统的稳定性,实现了气动调节阀的快速精准定位。

气动调节阀粘滞故障检测与参数辨识方法研究

为了研究气动调节阀的粘滞特性问题,以CHEN粘滞模型作为阀门粘滞特性问题的基础模型,提出一种阀门粘滞故障的检测与改进的参数辨识方法。通过搭建粘滞故障试验台,模拟实际情况中发生不同程度粘滞时的阀杆运动状态,揭示阀门粘滞发生的机理。使用随机森林算法对振荡源进行分类,实现对粘滞故障的检测。使用基于Hammerstein模型的粒子群优化算法求解粘滞参数最优解,提出粘滞双参数取值范围的确定方法,实现欠补偿、无补偿和过补偿3种状态下的粘滞参数辨识。结果表明:阀门粘滞程度与阀杆所受动静摩擦力有关;在不考虑外界因素的影响下,提出的粘滞检测方法对4种振荡源的分类准确率达到99.0268%;提出的改进的粘滞参数辨识方法对不同大小粘滞参数的辨识结果误差达到7%以内。研究成果为阀门粘滞故障的检测和参数辨识提供了理论方法,对粘滞模型的改进具有实际参考价值。

高压气动压力伺服系统的鲁棒控制

高压气动压力伺服系统的参数不确定性和未建模动态制约了其控制精度的提高,针对此提出了基于RISE的自适应鲁棒控制算法用于高压气动压力伺服系统的控制。考虑到核心元件高压电气伺服阀的控制性能对高压气动压力伺服系统高精度控制的影响,设计了交叉对比实验,实验结果表明,伺服阀位置控制算法有助于避免正弦信号失真、减小稳态压力抖动,系统压力控制算法能提高系统的响应速度和动态跟踪能力。

比例阀控气缸系统确定性鲁棒反步运动跟踪控制器

为实现气缸运动轨迹的高精度鲁棒控制,建立了比例阀控缸系统的数学模型,并基于反步法设计了一种能够有效抑制系统模型参数不确定性、未建模动态和外界扰动等因素影响的非线性确定性鲁棒控制器。利用MATLAB中的Simulink模块构建气缸运动轨迹跟踪控制系统仿真模型。采用MATLAB/Simulink中的xPC-Target开发了基于非线性确定性鲁棒控制器的气缸运动轨迹实时控制系统。仿真结果表明所设计控制器是可行的。试验结果表明该控制器能够有效地跟踪参考轨迹,跟踪0.3 Hz正弦轨迹时的最大跟踪误差为0.89 mm,约为幅值的2.97%;跟踪0.4 Hz正弦轨迹时的最大跟踪误差为1.02 mm,为幅值的3.4%。

气动调节阀定位控制算法的研究进展

气动调节阀作为工业自动化系统中的关键执行元件,其定位控制精度对于生产效率和系统安全具有重要意义。在气动调节阀定位控制领域,已有多种控制算法被提出并应用,如PID控制、模糊控制、神经网络控制等,这些算法在特定条件下取得了一定的控制效果,但仍存在一些不足,如气动系统的非线性、不确定性以及外部干扰等因素给定位控制带来了挑战。因此,本文过深入分析近年来国内外高校和研究机构在气动阀门定位控制算法方面的研究,对PID算法、预测控制算法、模糊控制算法等控制算法进行分析和总结,并在此基础上进行展望。

基于干扰观测的气动调节阀定位系统设计

阀门定位控制器作为调节阀的控制核心,决定着气动调节阀的调节精度和响应速度,在调节阀的运行中发挥着不可替代的作用。针对气动阀门定位系统的非线性、易受气源质量影响和模型不准确等问题,设计了一种基于干扰观测的气动调节阀定位系统。首先,建立气动调节阀定位系统的数学模型。然后,利用非线性干扰观测器估计模型不确定性和外部环境干扰,将干扰观测信息应用于反步控制器设计,以较好地处理气动调节阀系统在工业过程中受到的集总扰动(包括外界干扰、未建模动态和模型参数摄动等)影响。最后,使用Matlab对气动调节阀定位系统进行仿真,并对仿真结果进行了相应的数据分析。仿真结果和数据分析结果表明,非线性扰动观测器能够准确估计系统集总扰动。同时,与积分反步法的比较结果表明,所用控制方法的轨迹跟踪误差的均方根值更小、跟踪效果更好。在所设计控制器作用下,气动阀的实际阀位能够准确跟踪期望阀位轨迹。

船舶压载水处理系统中的遥控蝶阀概述

船舶压载水处理系统的遥控蝶阀,需要具有调节或开关功能;通过总结电动、气动、液压和电液式等遥控蝶阀的各自特点,如工作原理、优缺点等,为压载水处理系统遥控蝶阀选择提供建议。基于蝶阀频繁动作、高调节精度、低故障率、低成本、安装简便等方面考虑,建议选用气动调节蝶阀;若只要求具备开关功能,可根据船舶实际情况选择气动开关阀门或液压开关阀门。

具有故障诊断功能的智能电气阀门定位器设计

阐述智能电气阀门定位器中的气动调节阀控制特点,它具备故障诊断功能。为此,研制的智能电气阀门定位器,通过增加微低功耗压力传感器、自诊断电路,以及多变量的融合算法,使其不但具有故障自诊断功能,而且具有阀门故障的诊断与预警功能。

控制阀智能定位器控制算法及PID参数整定方法研究

智能阀门定位器作为气动控制阀系统的核心部件,其控制性能直接影响气动控制阀门的响应速度、调节精度、稳定性等,从而影响整个工业回路的控制效果。为提高气动控制阀的响应速度、调节精度和稳定性,减小控制阀性能不佳对工业管路系统的影响,设计了一种基于自私群体优化(SHO)算法的控制器。基于直行程的单作用膜片式气动控制阀的物理特性,对智能阀门定位器的PID控制器参数进行自动整定,测试优化后的控制效果,控制过程不出现超调和振荡现象。本方法为后续优化智能阀门定位器控制算法提供一定的参考价值。

GB/T 4213标准新旧对比及解析

随着控制阀新工艺、新结构、新技术等问题的日益更替,以及使用工况不断向各种高温高压、有毒有害等复杂工况转变,现有的GB/T 4213-2008《气动调节阀》标准已经满足不了市场的需求,因此更新标准刻不容缓。更新标准的目的是为了适应控制阀新技术进步和市场发展的需要,提高产品质量的同时也保障了产品使用的安全性能,促进资源的有效利用和循环使用,有效加强国内外贸易的同时促进国内外竞争力的提升,最终实现经济和社会的可持续发展战略。本文介绍了GB/T 4213-2024在GB/T 4213-2008基础上部分内容及章节的更新,气动控制阀在设计、制造和试验适用范围及在实际生产中可行性操作,阐述和解析了新版标准的主要修订条款和技术意义,为控制阀企业在制造产品时提供相应的依据和指导。

某核电厂汽轮机旁路排放系统调节阀无法正常开启问题探究

某核电厂1号机组蒸汽发生器(SG)二次侧水质恶化,机组后撤至蒸汽发生器冷却正常停堆模式(NS/SG),现场检查发现汽轮机旁路排放系统(GCT)调节阀GCT131VV无法正常开启。为探究该问题的原因,对调节阀仪控部件、气动执行机构、阀门本体等故障情况进行排查,并对阀门受热膨胀量、阀门本体阻力影响等因素进行分析。本文分析认为该问题的根本原因是阀杆的弯曲度偏大,叠加系统回路中存在异物夹在主阀芯和阀笼之间,导致阀杆开启阻力超限而无法正常开启,并提出了相应的改进建议。

气动控制阀流量特性检测系统的研究与设计

气动控制阀的流量特性是阀门设计和使用中的重要参数。传统的气动控制阀流量特性检测方法存在精度低、效率低、可操作性差等缺点。为提高气动控制阀流量特性检测系统的精度、效率和可操作性,采用虚拟仪器技术设计了一套气动控制阀流量特性检测系统。该系统以LabVIEW为软件开发平台,使用Ansys-fluent软件对气动控制阀的流场进行仿真模拟,根据仿真结果实时调整优化试验条件,使流量特性检测结果更加准确、可靠。通过对比实验验证了该检测系统的可靠性和精度,并对该检测系统的可行性进行了分析,为气动控制阀流量特性检测提供了一种新方法。

连铸动态二冷水控制系统设计

当前,在连铸板坯越来越厚,后续生产工艺对铸坯质量要求越来越高的情况下,在提高铸机产量的同时,保证铸坯质量满足工艺要求,是众多钢厂连铸生产的首要任务。而对二次冷却技术的深入细致研究,更有助于各钢厂提高铸坯质量和生产效率。文章基于西门子S7-1500完成对连铸二冷水系统的设计,并且在湖南华菱涟源钢铁有限公司3#连铸进行了调试、运行。系统由主控制器S7-1500、ET-200MP从站1、ET-200MP从站2、ET-200MP从站3、环网的交换机XC208组成。主控制器S7-1500对3个从站采集的信号进行分析处理,并输出控制信号。主控制器与从站之间利用PROFINET通讯,并利用XC208交换机组成环网。整个系统实现了二冷水根据拉速、铸坯模式、温度等自动调节水量、空气等功能。本设计在博途软件中进行硬件的组态,程序的编写,在WINCC上完成了画面的监控。