气缸压力的时频分析及其在内燃机故障诊断中的应用

对气缸压力进行时-频分析,探讨了气缸压力信号与气阀机构状态之间的关系.对气缸压力信号进行二进小波分解,计算分解后尺度1上信号各频带的能量比,从中提取诊断特征量,从而对气阀机构进行故障诊断.结果表明此方法是可行、有效的.     

掩模光刻机中找平控制研究

基片与掩模版(或找平版)找平技术是掩模光刻机中的一个关键技术,找平的结果直接决定了光刻机的分辨率精度。找平的目的就是要实现掩模版平面和基片平面的平行,实现基片与掩模版在移动到设定的一个微小间隙后,基片上的各点到掩模版的距离相同,从而保证基片上图形的一致性,提高设备的分辨率。找平过程的控制主要在对找平的判断、压力采集反馈、找平压力的控制等方面。     

300mm硅片化学机械抛光压力控制技术研究

介绍了一种应用于硅片化学机械抛光(CMP)设备的压力控制技术,综合利用在线检测方法和离线检测方法,借助于Matlab数值分析软件分析抛光主轴压力设定值、气缸气压值、传感器示值以及检测仪器测试值之间的关系,并建立了主轴压力闭环控制系统,达到精确控制主轴压力的目的。工艺实验证明,主轴压力闭环控制系统稳定、可靠、精确。     

基于LM331和单片机的压力数据采集

介绍一种基于单片机AT89C51和V/F转换器LM331的压力数据采集系统.该系统以AT89C51单片机为核心.实时测量由压力传感器MPXV5004G检测的压力.与传统电路设计相比较,其外部硬件电路少,结构简单,无较大的时延.只要对其功能进行扩展,能够实现相应控制.     

气动机械手控制技术的研究

气动机械手的全部动作由气动元件驱动,电磁阀控制,在本设计方案中使用气动伺服控制技术和计算机控制技术进行分级调速回路的控制,实现气缸不同的运动速度,从而使气缸在起动或停止时能够减少冲击,平缓地起动或停止。     

基于Labview的压力控制脉搏采集系统

为了提取更多的脉搏信息,设计出一种可控制压力大小的脉搏采集系统。该系统的设计不仅实现了对脉搏压力自动的选择,它还通过压力信号反馈于控制信号,控制信号决定加压还是减压．这样就保证了压力的稳定以及采集的脉搏信号的稳定。这克服了以往压力脉搏采集系统的压力不稳定的弊端,可以采集到稳定的脉搏信息。该系统还可以模拟脉诊系统中的浮、中、沉3种指力,这样就可以获取不同压力下的脉搏信号．可以方便对不同状态下的脉搏信号进行提取分析。     

一种基于MS5803的高精度超小型数字压力采编系统设计

传统压力采编系统存在节点数目较少、体积冗余以及重量较重等问题,无法满足监测者挖掘更充分信息并对飞行器做出调整的需求.对此,设计一种基于MS5803的高精度压力采编系统.系统选择高精度数字压力传感器MS5803作为系统传感单元,通过I2C驱动芯片与采编器连接实现传感阵列的远距离控制和数据传输,采编器连接监控台可以将采集编帧的数据上传至上位机,上位机可以对采集始止进行操作,并通过计算实现环境的实时监测.实验证明,系统整体具有超小型、高精度及灵活自检的特点,可以实现长距离下的多路并行采集和稳定通信,数据连贯稳定.系统连线简单,操作性极强,可根据需求进行分布式拓展,完成大规模测量阵列的压力采集任务.     

热水器容器脉冲压力试验要求分析及仪器设计

为满足GB/T20289-2006标准热水器容器压力试验要求,设计了相应试验装置,以PLC为核心控制水泵以调节容器试验所需压力,控制气动球阀来调节试验保压、卸压功能,实现自动测试达到标准所需的要求.     

基于可编程控制器的稳压器压力水位控制研究

本文研究了可编程控制器构建稳压器压力水位控制系统。通过对可编程控制器的软件控制技术、配置的灵活性、模块化结构以及功能模块的运用,能够保证稳压器压力水位控制系统自身的功能的实现。通过分析相关的实验结果,我们发现在控制水位以及稳压器压力的时候利用可编程控制器是完全可行的。     

一种新型的压力自动调节系统

汽轮机冷凝水回路中的压力受循环水泵出口水压和水阀开度共同影响,为确保冷凝水回路的正常运转,对冷凝水阀准确控制、保证水回路中的压力数值恒定就具有极其重要的作用.本文基于阀开度与压力之间的关系进行建模,进行阀开度的控制,从而实现了一种新型的压 力自动调节系统,以保障水回路中水流量的稳定性.     

土壤检测领域压力控制器的设计与开发

设计实现了一个应用于土壤力学试验中三轴仪测试系统的压力控制器,选用瑞萨M16C62P系列单片机作为控制器,步进电机与螺杆驱动活塞从而改变压力缸中的压力,压力值调节通过闭环控制实现,体积变化量由步进电机步进计数计算得到,特别是串行通讯的设计使用户可以通过上位机的友好界面对压力控制器进行控制和数据记录。     

A method for combustion phasing control using cylinder pressure measurement in a CRDI diesel engine

The start of combustion (SOC) in the combustion chamber has a considerable influence upon all performances of the engine. In this paper, cylinder pressure was investigated as a means for the closed-loop SOC control of a common-rail direct injection (CRDI) diesel engine. In order to detect the SOC, the crank angle position where the difference pressure became 10 bar was selected as the pressure variable. Using this pressure variable as a feedback variable, an adaptive feedforward control was proposed. The feedforward controller consisted of the radial basis function network (RBFN) and the feedback error learning method, which was used for the training of the network. The proposed SOC control strategy showed a far better regulation performance than that of the linear feedback controller. A further extension of the strategy based on the individual cylinder pressure feedback, the individual cylinder SOC control strategy, effectively reduced cylinder-by-cylinder SOC variation in steady and transient engine operations.     

基于PLC控制的变频调速恒压供水系统的探讨

为达到供水质量和供水系统可靠性的要求,再加上目前能源紧缺,利用先进的自动化技术、控制技术以及通讯技术,设计高性能、高节能、高适用性的恒压供水系统成为必然趋势。本文着重研究并提出了基于PLC和变频器的恒压供水系统的方案,并给出了硬件设计和PLC控制程序设计。采用PLC控制的变频调速供水系统,由PLC进行逻辑控制,由变频器进行压力凋节,再经过PID运算,通过PLC控制变频与工频切换,实现闭环自动调节恒压变量供水,通过压力传感器对水压的反馈构成闭环控制系统以及PID模块根据用水量的变化调节水泵的输出流量。运行结果表明,该系统具有压力稳定,结构简单,工作可靠等特点,并能达到有效节能的目的。     

Fractional order control to the electro-hydraulic system in insulator fatigue test device

In this paper, a special composite hydraulic cylinder, which includes two pistons and three working chambers, is proposed for driving the insulator fatigue test device. In this force loading system, a servo valve and a proportional pressure valve are used to control the composite hydraulic cylinder to generate alternating force and fixed force respectively. Furthermore, the models of the electro-hydraulic system are built and its dynamic characteristic is analyzed based on the models. Considering the uncertainty of the model parameters, the fractional order proportional-integral-derivative controller is adopted to control the two valves. The Oustaloup method is used to discrete the fractional order controller and the iteration feedback tuning method is presented to tune the controller parameters. The tuning process which is independent on the system model can be done on the close loop system. Simulation and experimental results have shown that the fractional order controller is effective.     

变频调速在恒压供水系统中的应用

针对在用水过程中缺水或水压不够及在用水量少时,水压过大产生爆管的问题,在供水系统中采用变频器,根据给定压力信号和反馈压力信号调节水泵转速,使管网中水压恒定的同时,实现了用水量与给水量的最佳匹配,达到了节能、节水的目的。     

基于CCD圆柱体压力非接触测量系统的研究

介绍了一种基于CCD圆柱体压力非接触测量系统的工作原理及总体构成，给出线阵CCD驱动电路的设计，并对测量误差进行了详细分析。实验结果表明该系统提供了一种传感器完全不受力、稳定可靠、适应各种测量环境、准确度高、结构简单、携带式的各种圆柱体构件非接触力测量。     

Methods for engine supervision and control based on cylinderpressure information

The increasing demands for low emissions and low fuel consumption in modern combustion engines require improved methods for online diagnosis and best possible control of the combustion process. It is demonstrated that the cylinder pressure signal can successfully be used for this task. After introduction of some theoretical background, several application examples are presented: an online supervision of fuel injection, some results on feedforward emission control, and a concept for feedback control of spark timing. Experimental results obtained from stock car diesel and spark ignition engines are included to support the automation concepts     

Pressure observer-controller design for pneumatic cylinder actuators

Recent research has shown that robust and precise high-speed control of pneumatic actuators is practicable, by application of advanced control techniques such as model-based adaptive and sliding-mode control. However, the resulting need for full state-based feedback and feedforward control-in particular, the measurement of air pressures-increases both the cost and complexity of the overall system. In this paper, we consider the problem of design of observers to estimate the chamber pressure variables in a cylinder actuator. Since the cylinder pressures are not simultaneously observable because of the nature of cylinder dynamics, we first propose a continuous gain observer in which the pressure on one side of the cylinder is measured and the pressure on the other side is estimated. Next, we propose a sliding-mode observer where numerically estimated acceleration is used in order to observe both pressures, with ultimate bounded stability. A sliding-mode controller is proposed, whose sensitivity to errors under the sliding-mode observer is studied. The proposed observers are simple, effective and easy to implement. Results of experimental implementation illustrate the practical effectiveness of the new observers.     

汽车驾驶模拟器二自由度运动系统

为汽车驾驶模拟器设计了一种二自由度运动系统。该系统采用电动驱动方式,提供仰俯、侧倾两个自由度运动。介绍了该系统软、硬件结构和相关控制算法。其中硬件系统由运动平台和电控系统构成,执行机构采用伺服电机及电动缸。软件系统将汽车运行参数解算成电动缸的控制参数,控制电动缸完成运动控制。平台可以实现汽车运行过程中的大部分体感模拟。