電渦流傳感器位移特性實(shí)驗(yàn)報(bào)告分析

1、電渦流傳感器位移特性實(shí)驗(yàn)實(shí)驗(yàn)報(bào)告專業(yè)：機(jī)械工程班級(jí)：機(jī)械7班學(xué)號(hào)：2201507003姓名：牛嘉彬2015年11月20日.、八、-一刖言長(zhǎng)度是測(cè)量中最常見的物理量之一，我們經(jīng)常要通過(guò)判斷物體的位移量來(lái)判斷物體的狀 態(tài)變化。除此之外，不少非位移變化量也是通過(guò)傳感器內(nèi)部器件相對(duì)位移來(lái)測(cè)量計(jì)算得出的。 位移傳感器又稱為線性傳感器，是一種屬于金屬感應(yīng)的線性器件，傳感器的作用是把各種被測(cè)物理量轉(zhuǎn)換為電量。在生產(chǎn)過(guò)程中，位移的測(cè)量一般分為測(cè)量實(shí)物尺寸和機(jī)械位移兩種。 按被測(cè)變量變換的形式不同，位移傳感器可分為模擬式和數(shù)字式兩種。模擬式又可分為物性型和結(jié)構(gòu)型兩種。常用位移傳感器以模擬式結(jié)構(gòu)型居多，包括電位器

2、式位移傳感器、電感式位移傳感器、自整角機(jī)、電容式位移傳感器、電渦流式位移傳感器、霍爾式位移傳感器等。 數(shù)字式位移傳感器的一個(gè)重要優(yōu)點(diǎn)是便于將信號(hào)直接送入計(jì)算機(jī)系統(tǒng)。這種傳感器發(fā)展迅 速，應(yīng)用日益廣泛。電渦流傳感器能靜態(tài)和動(dòng)態(tài)地非接觸、高線性度、高分辨力地測(cè)量被測(cè)金屬導(dǎo)體距探頭表面距離。作為一種非接觸的線性化計(jì)量工具，它能準(zhǔn)確測(cè)量被測(cè)體（必須是金屬導(dǎo)體）與 探頭端面之間靜態(tài)和動(dòng)態(tài)的相對(duì)位移變化。在高速旋轉(zhuǎn)機(jī)械和往復(fù)式運(yùn)動(dòng)機(jī)械狀態(tài)分析，振動(dòng)研究、分析測(cè)量中，對(duì)非接觸的高精度振動(dòng)、位移信號(hào)，能連續(xù)準(zhǔn)確地采集到轉(zhuǎn)子振動(dòng)狀 態(tài)的多種參數(shù)。如軸的徑向振動(dòng)、振幅以及軸向位置。電渦流傳感器以其長(zhǎng)期工作可靠性好

3、、 測(cè)量范圍寬、靈敏度高、分辨率高等優(yōu)點(diǎn)，在大型旋轉(zhuǎn)機(jī)械狀態(tài)的在線監(jiān)測(cè)與故障診斷中得 到廣泛應(yīng)用。因此我們需要來(lái)了解電渦流傳感器的相關(guān)特性。二.實(shí)驗(yàn)?zāi)康牧私怆姕u流傳感器測(cè)量位移的工作原理和特性。三電渦流傳感器的工作原理電渦流式傳感器是一種建立在渦流效應(yīng)原理上的傳感器。電渦流式傳感器由傳感器線圈和被測(cè)物體（導(dǎo)電體一金屬渦流片）組成，如圖1所示。根據(jù)電磁感應(yīng)原理，當(dāng)傳感器線圈（一個(gè)扁平線圈）通以交變電流（頻率較高，一般為 1MHz2MHz ） I1時(shí)，線圈周圍空間 會(huì)產(chǎn)生交變磁場(chǎng) H1，當(dāng)線圈平面靠近某一導(dǎo)體面時(shí)，由于線圈磁通鏈穿過(guò)導(dǎo)體，使導(dǎo)體的 表面層感應(yīng)出呈旋渦狀自行閉合的電流I2，而I2所形

4、成的磁通鏈又穿過(guò)傳感器線圈，這樣線圈與渦流“線圈”形成了有一定耦合的互感，最終原線圈反饋一等效電感，從而導(dǎo)致傳感器線圈的阻抗 Z發(fā)生變化。我們可以把被測(cè)導(dǎo)體上形成的電渦等效成一個(gè)短路環(huán)，這樣就 為傳感器線圖.2電渦流傳感器等效電路圖其電阻為R2、電感為L(zhǎng)2。線圈與導(dǎo)體圖1電渦流傳感器原理圖圈的電阻和電感。短路環(huán)可以認(rèn)為是一匝短路線圈， 間存在一個(gè)互感 M它隨線圈與導(dǎo)體間距的減小而增大。根據(jù)等效電路可列出電路方程組:R婦十丿血6婦-j泌f f二0厶厶=U2通過(guò)解方程組，可得11、12。因此傳感器線圈的復(fù)阻抗為:十& +(必)耐 +(%)線圈的等效電感為:線圈的等效Q值為：Q= Q01-(

5、 L 2® 2M 2)/( L 1 Z 22) / 1+(R2 co 2M 2)/( R1 Z 22) : 式中：Q0 無(wú)渦流影響下線圈的Q值，Q0=oL 1/R1;Z 22 金屬導(dǎo)體中產(chǎn)生電渦流部分的阻抗，Z 22= R22+o 2L22。由式Z、L和式Q可以看出，線圈與金屬導(dǎo)體系統(tǒng)的阻抗Z、電感L和品質(zhì)因數(shù)Q值都是該系統(tǒng)互感系數(shù)平方的函數(shù)，而從麥克斯韋互感系數(shù)的基本公式出發(fā)，可得互感系數(shù)是線圈與金屬導(dǎo)體間距離 x(H)的非線性函數(shù)。因此 Z、L、Q均是x的非線性函數(shù)。雖然它整個(gè) 函數(shù)是一非線性的，其函數(shù)特征為"S"型曲線，但可以選取它近似為線性的一段。其實(shí)Z、

6、L、Q的變化與導(dǎo)體的電導(dǎo)率、磁導(dǎo)率、幾何形狀、線圈的幾何參數(shù)、激勵(lì)電流頻率以及線圈到被測(cè)導(dǎo)體間的距離有關(guān)。如果控制上述參數(shù)中的一個(gè)參數(shù)改變，而其余參數(shù)不變，則阻抗就成為這個(gè)變化參數(shù)的單值函數(shù)。當(dāng)電渦流線圈、金屬渦流片以及激勵(lì)源確定后，并保持環(huán)境溫度不變，則只與距離 x有關(guān)。于此，通過(guò)傳感器的調(diào)理電路(前置器)處理，將線圈阻抗 Z、L、Q的變化轉(zhuǎn)化成電壓或電流的變化輸出。輸出信號(hào)的大小隨探頭到被測(cè)體表面之間的間距而變化，電渦流傳感器就是根據(jù)這一原理實(shí)現(xiàn)對(duì)金屬物體的位移、振動(dòng)等參數(shù)的測(cè)量。為實(shí)現(xiàn)電渦流位移測(cè)量，必須有一個(gè)專用的測(cè)量電路。這一測(cè)量電路(稱之為前置器， 也稱電渦流變換器)應(yīng)包括具有一定

7、頻率的穩(wěn)定的震蕩器和一個(gè)檢波電路等。電渦流傳感器位移測(cè)量實(shí)驗(yàn)框圖如圖 3所示：圖3電渦流位移特性實(shí)驗(yàn)框圖根據(jù)電渦流傳感器的基本原理，將傳感器與被測(cè)體間的距離變換為傳感器的Q值、等效4所示。阻抗Z和等效電感L三個(gè)參數(shù)，用相應(yīng)的測(cè)量電路(前置器)來(lái)測(cè)量。本實(shí)驗(yàn)的渦流變換器為變頻調(diào)幅式測(cè)量電路，電路原理與面板如圖圖4電渦流變換器原理圖與面板圖電路組成：Q1、C1、C2、C3組成電容三點(diǎn)式振蕩器，產(chǎn)生頻率為波信號(hào)。電渦流傳感器接在振蕩回路中，傳感器線圈是振蕩回路的一個(gè)電感元件。用是將位移變化引起的振蕩回路的Q值變化轉(zhuǎn)換成高頻載波信號(hào)的幅值變化。C6組成了由二極管和 LC形成的n形濾波的檢波器。器檢測(cè)到

8、的低頻信號(hào)取出來(lái)。 Q2組成射極跟隨器。以獲得盡可能大的不失真輸出的幅度值。電渦流傳感器是通過(guò)傳感器端部線圈與被測(cè)物體1MHz左右的正弦載振蕩器作 D1、C5 L2、檢波器的作用是將高頻調(diào)幅信號(hào)中傳感 射極跟隨器的作用是輸入、輸出匹配（導(dǎo)電體）間的間隙變化來(lái)測(cè)物體的振 動(dòng)相對(duì)位移量和靜位移的，它與被測(cè)物之間沒有直接的機(jī)械接觸，具有很寬的使用頻率范圍（從010Hz）。當(dāng)無(wú)被測(cè)導(dǎo)體時(shí)，振蕩器回路諧振于f0 ,傳感器端部線圈 Q0為定值且最高， 對(duì)應(yīng)的檢波輸出電壓 Vo最大。當(dāng)被測(cè)導(dǎo)體接近傳感器線圈時(shí)，線圈Q值發(fā)生變，振蕩器的諧振頻率發(fā)生變化，諧振曲線變得平坦，檢波出的幅值Vo變小。Vo變化反映了位

9、移x的變化。電渦流傳感器在位移、振動(dòng)、轉(zhuǎn)速、探傷、厚度測(cè)量上得到應(yīng)用。四實(shí)驗(yàn)準(zhǔn)備器材機(jī)頭中的振動(dòng)臺(tái)、測(cè)微頭、電渦流傳感器、被測(cè)體（鐵圓片）；顯示面板中的F/ V表（或 電壓表）；調(diào)理電路面板傳感器輸出單元中的電渦流、調(diào)理電路面板中的渦流變換器 五實(shí)驗(yàn)步驟1、調(diào)節(jié)測(cè)微頭初始位置的刻度值為 調(diào)整電渦流傳感器高圖5 電渦流傳感 器位移特性實(shí)驗(yàn)接線示 意圖2、將電壓表（F/ V表）量程切換開關(guān)切換 到20V檔，檢查接線無(wú) 誤后合上主、副電源開 關(guān)（在渦流變換器輸入 端可接示波器觀測(cè)振蕩 波形），記下電壓表讀 數(shù)，然后逆時(shí)針調(diào)節(jié)測(cè) 微頭微分筒每隔0.1mm讀一個(gè)數(shù)，直到輸出 Vo 變化很小為止并將數(shù)據(jù)

10、列入表1表1電渦流傳感器 位移X與輸出電壓數(shù)據(jù)5mm處，松開電渦流傳感器的安裝軸套緊固螺釘，度與電渦流檢測(cè)片相帖時(shí)擰緊軸套緊固螺釘并按圖5示意接線。111Q a/I頭 I局 隅I圖HIIII IIIIIIIIIIIIHIIiiJLF冉麥 舷莉電財(cái)-o-© r«謹(jǐn) 理I 電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根據(jù)表1數(shù)據(jù)作出V

11、-X實(shí)驗(yàn)曲線。在實(shí)驗(yàn)曲線上截取線性較好的區(qū)域作為傳感器的位 移量程計(jì)算靈敏度和線性度（可用最小二乘法或其它擬合直線）。實(shí)驗(yàn)完畢，關(guān)閉所有電源。六數(shù)據(jù)分析Matlab使用GUI編輯 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)%