第六讲航空发动机试验中电子扫描压力测量不确定度评定——测量方法和电子扫描压力测量系统的测量不确定度评定

1 概述 电子扫描压力测量系统是精度较高的多点压力测量设备.在这样的系统中,每一个测压通道都配有一只压力传感器(通常是硅压阻式压力传感器),这些压力传感器本身的准确度等级不是很高,特别是受温度变化的影响比较大.为了获得高准确度的压力测量数据,目前,有以下两种方法减小这些压力传感器的压力测量误差.     

用硅压阻式压力传感器解算高度速度的方法

简要阐述了解算气压高度速度的原理，对使用硅压阻式压力传感器来解算高度速度的误差和传感器选择作了详细分析，结果表明，用硅压阻式压力传感器来作简易的高度速度测量，可达到中等测量精度的水平。     

一种扩散硅压力式密度静态测量系统

全面实现轻化工过程的自动控制,溶液的密度（或浓度）等成分的测量是一个关键问题。通过多个扩散硅压力式传感器,结合单片机系统,实现了溶液密度的静态测量,并取得了较好的实验测量效果。     

基于多传感器融合的压力测量系统设计

当今，所有以微处理器为基础的测控系统都需要传感器来提供做出实时决策的数据。本文详细阐述了压力传感器测量系统硬件设计、压力传感器智能化软件设计、压力传感器误差与温度补偿技术设计。针对传感器测量的温度漂移和非线性等问题，提出了利用多传感器信息融合技术--曲面拟合法和曲线拟合法来加以解决，并实现PC机与传感器测量系统之间的通信，完成数据转换、数据处理和打印等功能，使测量系统更加完善。     

硅压阻式压力传感器的高精度补偿算法及其实现

硅压阻式压力传感器广泛应用于汽车、医疗、航空航天、环保等领域。随着科学技术的发展,各领域对压力测量精度的要求越来越高。但由于半导体材料的固有特性,硅压阻式压力传感器普遍存在零点随温度漂移、灵敏度随温度变化和非线性等问题。为了提高硅压阻式压力传感器测量精度、降低输出误差,对该传感器的几种常用补偿算法进行了对比分析和研究,提出了一种基于最小二乘法的曲面拟合高精度补偿算法。该补偿算法能有效消除硅压阻式压力传感器零点漂移、灵敏度漂移和非线性误差,提高该传感器的输出精度。试验结果表明,在-40^+80℃温度范围内,硅压阻式压力传感器经该补偿算法计算后,测量精度得以大幅度提高,输出误差小于0.01%F·S。     

基于自主传感器信号调理芯片温度补偿的软件设计

利用现代信号调理技术,以自主设计的信号调理芯片为核心,采用C#设计开发了硅压阻式传感器的智能误差补偿校准软件,实现了对核心补偿芯片的可视化操作与控制,解决了传统的硬件电路对压力传感器进行温度补偿的缺点。在多个温度点进行校准获取补偿曲线,得到零点及温度漂移补偿数据,解决了硅压阻式传感器一致性差、温度漂移和非线性等问题。系统运行结果表明:通过使用补偿软件,采用高精度温度补偿算法的传感器输出精度有了明显提高,在-55℃～125℃的温度范围内输出的信号与压力成良好的线性关系,压力参数测量精度达到了0.6%以内。     

一种硅微多传感器集成研究

为满足小体积、多参数测量的要求,利用(100)晶面的各向异性压阻特性与MEMS加工工艺特性,在单芯片上集成制作了三轴加速度、绝对压力以及温度等硅微传感器,在结构和检测电路设计上最大限度地减小各传感器之间的相互干扰影响。三轴加速度、绝对压力传感器利用压阻效应导致的电阻变化测量外界加速度和压力变化量,温度传感器利用掺杂单晶硅电阻率随温度变化的原理来测量外界温度。集成传感器具有较好的工艺兼容性,加速度、压力传感器的压敏电阻和温度传感器的测温电阻采用硼离子掺杂制作,加速度和压力传感器设计成工艺兼容的体硅结构。研制的集成传感器芯片尺寸为4mm×6mm×0.9mm。给出了集成传感器的性能测试结果。     

应力隔离法在蓝宝石压力传感器结构设计中的应用

对硅-蓝宝石硅压力传感器C型弹性膜片接头结构和E型弹性膜片接头结构进行建模分析,优化设计应力隔离槽结构,并应用于硅-蓝宝石压力传感器一体化设计的弹性膜片与接头结构.较好地解决了硅-蓝宝石压力传感器的零点输出、满量程输出在不对称安装应力下产生偏移,影响传感器的测量精度的问题,使传感器的安全性、可靠性进一步提高,优化结构后的传感器在航天领域具有广泛的应用.     

基于MPX2100型压力传感器的高精度数据采集系统

在压力的测量与分析中,通常压力值的变化速度不快,但要求测量精度很高.本文介绍了一种基于MPX2100型压力传感器的高精度压力数据采集系统,给出了X型硅压力传感器MPX2100以及A/D转换核心部件ICL71 35各自的性能特点及其相关接□电路;提供了系统的组成框图、各主要部分电路图及A/D转换软件设计流程图.     

多通道压力传感器多参数自动测试系统设计

设计了一种压力传感器自动测试系统,可实现对多路传感器和多个参数的自动切换测量.通过设计的多功能矩阵开关电路配合一台高精度数据采集器,实现选通切换与测量;采用LabVIEW设计上位机软件,实现标定数据、温度补偿数据、时漂数据显示以及计算、报表功能.实验证明：该系统可同时进行90只压力传感器的桥路电压、电阻、电流等参数测量,满足精度为1％～0.1％压力传感器批量产品检测与检定的多种测试需要.     

Sensor-fusion of hydraulic data for burst detection and location in a treated water distribution system

This paper presents research into analysis and data fusion for sensors measuring hydraulic parameters (flow and pressure) of the pipeline water flow in treated water distribution systems. An artificial neural network (ANN) based system is used on time series data produced by sensors to construct an empirical model for the prediction and classification of leaks. A rules based system performs a fusion on the ANNs’ outputs to produce an overall state classification for a set of zones. Results are presented using data from an experimental site in a distribution system of a UK water company in which bursts were simulated by hydrant flushing. The ANN system successfully detected events and a study of the pressure gradient across the zone provided a more precise location within the zone.     

Development of a MEMS-based control system for compressible flow separation

A MEMS-based sensor and actuator system has been designed and fabricated for separation control in the compressible flow regime. The MEMS sensors in the system are surface-micromachined shear stress sensors and the actuators are bulk-micromachined balloon vortex generators (VGs). A three-dimensional (3-D) wing model embedded with the shear stress sensors and balloon VGs was tested in a transonic wind tunnel to evaluate the performance of the control system in a range of Mach number between 0.2 and 0.6. At each Mach number tested, the shear stress sensors quantify the boundary layer on the surface of the wing model while the balloon VGs interact with the boundary layer in an attempt to provide flow control. The shear stress measurements indicate the presence of a separated flow on the trailing ramp section of the wing model at all Mach numbers tested when the balloon VGs are not activated. This result is confirmed by total pressure measurements downstream from the wing model where a wake profile is observed. When the balloon VGs are activated, the shear stress level on the trailing ramp increases with the Mach number. At the highest Mach number tested, this increase elevates the shear stress on the ramp to almost the same level as the unseparated flow, suggesting the possibility of a boundary layer reattachment. This result is supported by the downstream pressure measurements which show a large pressure recovery when the balloon VGs are activated. The wind tunnel experiment successfully demonstrated two aspects of the MEMS flow control system: the effectiveness of the microshear stress sensors in measuring the separation characteristics of a high-speed compressible flow and the ability of the microballoons in positively enhancing the aerodynamic performance of a high-speed wing through boundary layer modification.     

基于PLC和变频调速的恒压供水系统设计

为了解决水压波动问题,基于恒压供水的原理,设计并实现了由PLC、变频器和压力传感器等组成的恒压供水系统。系统根据管网压力自动调节供水量,实现了恒压供水的目的。     

Fault-tolerant sensor integration for micro flow-sensor arrays and networks

Distributed micro flow-sensor arrays and networks (DMFSA/N), built from collections of spatially scattered, cooperating intelligent and redundant micro flow-sensor nodes, can improve the accuracy and reliability of system. However, it is unrealistic to expect all the sensor nodes and communication links in the system to function properly all the time. This paper is based on an earlier research, in which a DMFSA/N with a cluster architecture and fault-tolerant time-out Protocol (FTTP) was developed. In this paper, a fault-tolerant sensor integration algorithm (FTSIA) is proposed and evaluated in simulations. Experimental results showed that the FTSIA could always give reliable results even when certain portion of the sensors yielded faulty information. Furthermore, the results from FTSIA were significantly more accurate than the mean of sensor readings (popularly applied in industry) if some of the sensors produced faulty readings. Finally, the application of the proposed FTSIA is illustrated by measuring flow pressure using a pressure sensor array of eight sensors.     

基于IEEE1588的分布式柔性测压带系统设计

为了研发一套分布式翼面柔性测压带系统,实现以表面贴附的方式测量飞机翼面压力,同时满足大规模分散式的传感器节点数据的同步采集、实时传输和本地存储等功能,提出系统总体设计方案,提供了硬件设计方法和软件设计流程。测试了系统的各项性能,并进行系统性能评估。测试结果表明:该系统达到了预期的技术指标,符合测试平台的要求;该系统是通用的,可以将压力传感器换成其他类型的传感器,尤其对于需要大量传感器的测试环境,其提供了一种安装方便、扩展灵活、数据传输可靠的解决方案。     

基于压力传感器与摄像头的颈椎病预防系统

本文设计并实现了一种基于压力传感器与摄像头的颈椎病预防系统.该系统将薄膜压力传感器放置于坐垫中对人体体压进行采集,并使用摄像头采集人类脸部数据.对于坐垫,我们对传感器的布置和数目进行了优化.对于摄像头,我们在多目标识别时通过五官识别减少了系统运算量.在将压力传感器与摄像头两类数据融合之后,我们实现了比单类数据更准确的坐姿识别,进而对颈椎病的危险程度进行估计.我们还使用卷积神经网络实现了对用户的动作检测,可引导用户完成一系列动作用于评估颈椎病危险程度.系统实现小巧美观,采用非侵入式的方法,非常适合于在办公室环境下的颈椎病早期预防.     

基于皮托管的流场测试系统开发

针对流场测量采集数据处理复杂的特点,设计了基于单片机的数据采集系统,以满足多变的测试需求的基础环节;在介绍了测试原理后,给出了硬件模块及接口间的设计思路和工作过程,重点分析了软件设计流程;通过流场校验试验和测量试验,对五组压力传感器采集到的数据进行处理,验证采集系统的稳定性和流场测量装置的性能;试验结果表明:测试系统实现了对三维伴流场的测量和对传统传感器的身份识别,并提高了测试的效率;为进一步实现对其他传感器及测试系统的改造提供基础。     

雾化喷头性能测试实时监控系统的设计

根据对控制要求的分析,采用西门子PLC+MCGS组态技术来实现恒压、恒流监控功能;PLC用来采集传感器的输入/输出信号,并且通过PLC闭环PI控制的方式实现对QSVY型电动调节阀的连续控制,达到管道出口参数恒定的目的;PLC通过各种传感器测量各设备的运行状态,并把信息传送给上位机,上位机组态软件通过监控画面把设备的运行状态变化用动画、曲线形式表现出来;试验时,采用美国喷雾系统公司的XR-TEEJET11002型喷头进行控制系统的控制性能分析;当K=0.3,T=0.04时,过程值与设定值曲线基本重合,最大控制误差为0.01Mpa,且输出几乎不振荡,并可实现压力0.01Mpa的调节精度,流量1L/min的调节精度,说明本设计系统可靠。     

MEMS压力传感器批量组装设备的研制

针对当前MEMS产业化推进过程中的小批量的发展现状,研究面向批量组装的MEMS微操作实用化系统具有重要实际价值.针对MEMS高温压力传感器产业化发展过程中的批量化键合工艺需求,从分析压力传感器键合工艺入手,研究批量组装关键技术,最后进行系统集成研制MEMS压力传感器批量组装设备.批量组装实验表明该系统可实现典型MEMS传感器批量组装,对MEMS产业化发展具有重要意义.     

Local heat transfer process and pressure drop in a micro-channel integrated with arrays of temperature and pressure sensors

One of the most important components in micro-fluidic system is the micro-channel which involves complicated flow and transport process. This study presents micro-scale thermal fluid transport process inside a micro-channel with a height of 37 μm. The channel can be heated on the bottom wall and is integrated with arrays of pressure and temperature sensors which can be used to measure and determine the local heat transfer and pressure drop. A more simplified model with modification of Young’s Modulus from the experimental test is used to design and fabricate the arrays of pressure sensors. Both the pressure sensors and the channel wall use polymer materials which greatly simplify the fabrication process. In addition, the polymer materials have a very low thermal conductivity which significantly reduces the heat loss from the channel to the ambient that the local heat transfer can be accurately measured. The air flow in the micro-channel can readily become compressible even at a very low Reynolds number condition. Therefore, simultaneous measurement of both the local pressure drop and the temperature on the heated wall is required to determine the local heat transfer. Comparison of the local heat transfer for a compressible air flow in micro-channel is made with the theoretical prediction based on incompressible air flow in large-scale channel. The comparison has clarified many of the conflicting results among different works.