电涡流传感器位移特性实验报告分析

1、电涡流传感器位移特性实验实验报告专业：机械工程班级：机械7班学号：2201507003姓名：牛嘉彬2015年11月20日.、八、-一刖言长度是测量中最常见的物理量之一，我们经常要通过判断物体的位移量来判断物体的状 态变化。除此之外，不少非位移变化量也是通过传感器内部器件相对位移来测量计算得出的。 位移传感器又称为线性传感器，是一种属于金属感应的线性器件，传感器的作用是把各种被测物理量转换为电量。在生产过程中，位移的测量一般分为测量实物尺寸和机械位移两种。 按被测变量变换的形式不同，位移传感器可分为模拟式和数字式两种。模拟式又可分为物性型和结构型两种。常用位移传感器以模拟式结构型居多，包括电位器

2、式位移传感器、电感式位移传感器、自整角机、电容式位移传感器、电涡流式位移传感器、霍尔式位移传感器等。 数字式位移传感器的一个重要优点是便于将信号直接送入计算机系统。这种传感器发展迅 速，应用日益广泛。电涡流传感器能静态和动态地非接触、高线性度、高分辨力地测量被测金属导体距探头表面距离。作为一种非接触的线性化计量工具，它能准确测量被测体（必须是金属导体）与 探头端面之间静态和动态的相对位移变化。在高速旋转机械和往复式运动机械状态分析，振动研究、分析测量中，对非接触的高精度振动、位移信号，能连续准确地采集到转子振动状 态的多种参数。如轴的径向振动、振幅以及轴向位置。电涡流传感器以其长期工作可靠性好

3、、 测量范围宽、灵敏度高、分辨率高等优点，在大型旋转机械状态的在线监测与故障诊断中得 到广泛应用。因此我们需要来了解电涡流传感器的相关特性。二.实验目的了解电涡流传感器测量位移的工作原理和特性。三电涡流传感器的工作原理电涡流式传感器是一种建立在涡流效应原理上的传感器。电涡流式传感器由传感器线圈和被测物体（导电体一金属涡流片）组成，如图1所示。根据电磁感应原理，当传感器线圈（一个扁平线圈）通以交变电流（频率较高，一般为 1MHz2MHz ） I1时，线圈周围空间 会产生交变磁场 H1，当线圈平面靠近某一导体面时，由于线圈磁通链穿过导体，使导体的 表面层感应出呈旋涡状自行闭合的电流I2，而I2所形

4、成的磁通链又穿过传感器线圈，这样线圈与涡流“线圈”形成了有一定耦合的互感，最终原线圈反馈一等效电感，从而导致传感器线圈的阻抗 Z发生变化。我们可以把被测导体上形成的电涡等效成一个短路环，这样就 为传感器线图.2电涡流传感器等效电路图其电阻为R2、电感为L2。线圈与导体图1电涡流传感器原理图圈的电阻和电感。短路环可以认为是一匝短路线圈， 间存在一个互感 M它随线圈与导体间距的减小而增大。根据等效电路可列出电路方程组:R妇十丿血6妇-j泌f f二0厶厶=U2通过解方程组，可得11、12。因此传感器线圈的复阻抗为:十& +(必)耐 +(%)线圈的等效电感为:线圈的等效Q值为：Q= Q01-(

5、 L 2® 2M 2)/( L 1 Z 22) / 1+(R2 co 2M 2)/( R1 Z 22) : 式中：Q0 无涡流影响下线圈的Q值，Q0=oL 1/R1;Z 22 金属导体中产生电涡流部分的阻抗，Z 22= R22+o 2L22。由式Z、L和式Q可以看出，线圈与金属导体系统的阻抗Z、电感L和品质因数Q值都是该系统互感系数平方的函数，而从麦克斯韦互感系数的基本公式出发，可得互感系数是线圈与金属导体间距离 x(H)的非线性函数。因此 Z、L、Q均是x的非线性函数。虽然它整个 函数是一非线性的，其函数特征为"S"型曲线，但可以选取它近似为线性的一段。其实Z、

6、L、Q的变化与导体的电导率、磁导率、几何形状、线圈的几何参数、激励电流频率以及线圈到被测导体间的距离有关。如果控制上述参数中的一个参数改变，而其余参数不变，则阻抗就成为这个变化参数的单值函数。当电涡流线圈、金属涡流片以及激励源确定后，并保持环境温度不变，则只与距离 x有关。于此，通过传感器的调理电路(前置器)处理，将线圈阻抗 Z、L、Q的变化转化成电压或电流的变化输出。输出信号的大小随探头到被测体表面之间的间距而变化，电涡流传感器就是根据这一原理实现对金属物体的位移、振动等参数的测量。为实现电涡流位移测量，必须有一个专用的测量电路。这一测量电路(称之为前置器， 也称电涡流变换器)应包括具有一定

7、频率的稳定的震荡器和一个检波电路等。电涡流传感器位移测量实验框图如图 3所示：图3电涡流位移特性实验框图根据电涡流传感器的基本原理，将传感器与被测体间的距离变换为传感器的Q值、等效4所示。阻抗Z和等效电感L三个参数，用相应的测量电路(前置器)来测量。本实验的涡流变换器为变频调幅式测量电路，电路原理与面板如图图4电涡流变换器原理图与面板图电路组成：Q1、C1、C2、C3组成电容三点式振荡器，产生频率为波信号。电涡流传感器接在振荡回路中，传感器线圈是振荡回路的一个电感元件。用是将位移变化引起的振荡回路的Q值变化转换成高频载波信号的幅值变化。C6组成了由二极管和 LC形成的n形滤波的检波器。器检测到

8、的低频信号取出来。 Q2组成射极跟随器。以获得尽可能大的不失真输出的幅度值。电涡流传感器是通过传感器端部线圈与被测物体1MHz左右的正弦载振荡器作 D1、C5 L2、检波器的作用是将高频调幅信号中传感 射极跟随器的作用是输入、输出匹配（导电体）间的间隙变化来测物体的振 动相对位移量和静位移的，它与被测物之间没有直接的机械接触，具有很宽的使用频率范围（从010Hz）。当无被测导体时，振荡器回路谐振于f0 ,传感器端部线圈 Q0为定值且最高， 对应的检波输出电压 Vo最大。当被测导体接近传感器线圈时，线圈Q值发生变，振荡器的谐振频率发生变化，谐振曲线变得平坦，检波出的幅值Vo变小。Vo变化反映了位

9、移x的变化。电涡流传感器在位移、振动、转速、探伤、厚度测量上得到应用。四实验准备器材机头中的振动台、测微头、电涡流传感器、被测体（铁圆片）；显示面板中的F/ V表（或 电压表）；调理电路面板传感器输出单元中的电涡流、调理电路面板中的涡流变换器 五实验步骤1、调节测微头初始位置的刻度值为 调整电涡流传感器高图5 电涡流传感 器位移特性实验接线示 意图2、将电压表（F/ V表）量程切换开关切换 到20V档，检查接线无 误后合上主、副电源开 关（在涡流变换器输入 端可接示波器观测振荡 波形），记下电压表读 数，然后逆时针调节测 微头微分筒每隔0.1mm读一个数，直到输出 Vo 变化很小为止并将数据

10、列入表1表1电涡流传感器 位移X与输出电压数据5mm处，松开电涡流传感器的安装轴套紧固螺钉，度与电涡流检测片相帖时拧紧轴套紧固螺钉并按图5示意接线。111Q a/I头 I局 隅I图HIIII IIIIIIIIIIIIHIIiiJLF冉麦 舷莉电财-o-© r«谨 理I 电I 路| 面IX( mr)7.27.17.06.96.86.76.66.56.46.3Vo(V)0-0.24-0.37-0.52-0.69-0.79-0.95-1.05-1.18-1.33Vo(V)0-0.24-0.37-0.53-0.68-0.79-0.97-1.06-1.20-1.33根据表1数据作出V

11、-X实验曲线。在实验曲线上截取线性较好的区域作为传感器的位 移量程计算灵敏度和线性度（可用最小二乘法或其它拟合直线）。实验完毕，关闭所有电源。六数据分析Matlab使用GUI编辑 m文件如下:fun cti onvarargout = ni he_gui(vararg in)%NIHE_GUI M-file for n ihe_gui.fig%NIHE_GUI,by itself,createsanew NIHE_GUI or raisesthe exist ing%sin glet on*%H= NIHE_GUI returnsthehan dleto a newNIHE_GUI orthe

12、 han dleto%the existi ng sin glet on*%NIHE_GUI('Property','Value',.)createsa new NIHE_GUI usingthe%give npropertyvaluepairs.Un recog ni zedpropertiesare passedvia% varargin to n ihe_gui_Ope nin gFc n. This calli ng syn tax produces a% warning whe n there is an existi ng sin glet on*%

13、 NIHE_GUI('CALLBACK') and NIHE_GUI('CALLBACK',hObject,.) call the% local fun ction named CALLBACK in NIHE_GUI.M with the give n in put% argume nts.% *See GUI Opti ons on GUIDE's Tools me nu. Choose "GUI allows only one% in sta nee to run (sin glet on)".% See also: GUIDE

14、, GUIDATA, GUIHANDLES% Edit the above text to modify the resp onse to help ni he_gui % Last Modified by GUIDE v2.5 14-Dec-2015 19:05:47% Begin initialization code - DO NOT EDITgui_S in glet on = 1; gui_State = struct('gui_Name',mfile name,.'gui_S in glet on',gui_S in glet on,'gui

15、_Ope nin gFc n',n ihe_gui_Ope nin gFc n,'gui_OutputFc n',ni he_gui_OutputFc n,'gui_LayoutFc n', .'gui_Callback',)；if nargin && ischar(varargin1)gui_State.gui_Callback = str2func(varargin1);endif nargoutvarargout1:nargout = gui_mainfcn(gui_State, varargin:);elsegui

16、_mainfcn(gui_State, varargin:);end% End initialization code - DO NOT EDIT% - Executes just before nihe_gui is made visible.function nihe_gui_OpeningFcn(hObject, eventdata, handles, varargin)% This function has no output args, see OutputFcn.% hObject handle to figure% eventdata reserved - to be defin

17、ed in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% varargin unrecognized PropertyName/PropertyValue pairs from the%command line (see VARARGIN)% Choose default command line output for nihe_gui handles.output = hObject;% Update handles structure guidata(hObje

18、ct, handles);% UIWAIT makes nihe_gui wait for user response (see UIRESUME)% uiwait(handles.figure1);% - Outputs from this function are returned to the command line. functionvarargout = nihe_gui_OutputFcn(hObject, eventdata, handles)% varargout cell array for returning output args (see VARARGOUT);% h

19、Object handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Get default command line output from handles structure varargout1 = handles.output;% hObject handle to edit1 (see GCBO)% eventdata reserved - to be d

20、efined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit1 as text%str2double(get(hObject,'String') returns contents of edit1 asa double% - Executes during object creation, after setting all

21、 properties. functionedit1_CreateFcn(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty- handles not created untilafter all CreateFcnscalled% Hint: edit controls usually have a white background on Windows.

22、 % See ISPC and COMPUTER.if ispc && isequal(get(hObject,'BackgroundColor'),)get(0, 'defaultUicontrolBackgroundColor'set(hObject, 'BackgroundColor' , 'white' );end function edit2_Callback(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventda

23、ta reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit2 as text%str2double(get(hObject,'String') returns contents of edit2 asa double% - Executes during object creati

24、on, after setting all properties. function edit2_CreateFcn(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLABcalled% handles empty - handles not created until after all CreateFcns% Hint: edit controls usually have a whit

25、e background on Windows.% See ISPC and COMPUTER.if ispc && isequal(get(hObject,'BackgroundColor' ),get(0, 'defaultUicontrolBackgroundColor' )set(hObject,end'BackgroundColor', 'white' );% - Executes on button press in pushbutton1.function pushbutton1_Callback(h

26、Object, eventdata, handles)% hObject handle to pushbutton1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) x=str2num(get(handles.edit1,'string');y=str2num(get(handles.edit2,'string');p=polyfit(x

27、,y,1);x1=max(x):-0.1:min(x); y2=polyval(p,x1);axes(handles.axes1)plot(x,y, '*r' ,x1,y2);% - Executes on button press in pushbutton2.function pushbutton2_Callback(hObject, eventdata, handles)% hObject handle to pushbutton2 (see GCBO)% eventdata reserved - to be defined in a future version of

28、MATLAB % handles structure with handles and user data (see GUIDATA) x=str2num(get(handles.edit1,'string');y=str2num(get(handles.edit2,'string');p=polyfit(x,y,1);x1=max(x):-0.1:min(x); y2=polyval(p,x1);e=abs(y-y2); axes(handles.axes1) plot(x,e);% - Executes on button press in pushbutt

29、on3.function pushbutton3_Callback(hObject, eventdata, handles)% hObject handle to pushbutton3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)'string' );'string' );'string' );x=str2num(ge

30、t(handles.edit1,y=str2num(get(handles.edit2, y1=str2num(get(handles.edit3, e2=abs(y-y1);x1=max(x):-0.1:min(x);axes(handles.axes1) plot(x,e2);% - Executes on button press in pushbutton4.function pushbutton4_Callback(hObject, eventdata, handles)% hObject handle to pushbutton4 (see GCBO)% eventdata res

31、erved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) close;function edit3_Callback(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with ha

32、ndles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit3 as text%str2double(get(hObject,'String') returns contents of edit3 asa double% - Executes during object creation, after setting all properties.function edit3_CreateFcn(hObject, eventdata, handle

33、s)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLABcalled% handles empty - handles not created until after all CreateFcns% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc && isequal(get(hObjec

34、t,'BackgroundColor' ),get(0, 'defaultUicontrolBackgroundColor' )set(hObject, 'BackgroundColor' , 'white' ); end function edit4_Callback(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB%

35、handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit3 as text%str2double(get(hObject,'String') returns contents of edit3 asa double% - Executes during object creation, after setting all properties.fun cti onedit4_CreateFc n( hObject, eve ntdata, han dles)% hObject han dle to edit3 (see GCBO)%