1、AGuideGuideToTousingusingIMUIMU(Accelerometer(AccelerometerGyroscopeGyroscopeDevices)Devices)ininEmbeddedEmbeddedApplications.Applications.在嵌入式應用中使用在嵌入式應用中使用IMUIMU（加速度計和陀螺儀的設備）指南。（加速度計和陀螺儀的設備）指南。(翻譯部分翻譯部分)PartPart1.1.Acc

2、elerometerAccelerometer第一部分第一部分加速度計加速度計Tounderstthisunitwellstartwiththeaccelerometer.Whenthinkingaboutaccelerometersitisoftenusefultoimageaboxinshapeofacubewithaballinsideit.Youmayimaginesomethingelselikeacookieadonutbu

3、tIllimagineaball:要了解這個模塊我們先從加速度計開始。當我們在想象一個加速度計的時候我們可以把它想作一個圓球在一個方盒子中。你可能會把它想作一個餅干或者甜圈，但我就把它當做一個球好了：Ifwetakethisboxinaplacewithnogravitationfieldsfthatmatterwithnootherfieldsthatmightaffecttheballsposition–theballwillsim

4、plyfloatinthedleofthebox.Youcanimaginetheboxisinouterspacefarfarawayfromanycosmicbodiesifsuchaplaceishardtofindimagineatleastaspacecraftbitingaroundtheplawhereeverythingisinweightlessstate.Fromthepictureaboveyoucanseetha

5、tweassigntoeachaxisapairofwalls(weremovedthewallYsowecanlookinsidethebox).Imaginethateachwallispressuresensitive.Ifwemovesuddenlytheboxtotheleft(weaccelerateitwithacceleration1g=9.8ms^2)theballwillhitthewallX.Wethenmeasu

6、rethepressurefcethattheballappliestothewalloutputavalueofInthiscasetheboxisntmovingbutwestillgetareadingof1gontheZaxis.Thepressurethattheballhasappliedonthewallwascausedbyagravitationfce.Intheyitcouldbeadifferenttypeoffc

7、e–fexampleifyouimaginethatourballismetallicplacingamagnexttotheboxcouldmovetheballsoithitsanotherwall.Thiswassaidjusttoprovethatinessenceaccelerometermeasuresfcenotacceleration.Itjusthappensthataccelerationcausesaninerti

8、alfcethatiscapturedbythefcedetectionmechanismoftheaccelerometer.WhilethismodelisnotexactlyhowaMEMSsensisconstructeditisoftenusefulinsolvingaccelerometerrelatedproblems.Thereareactuallysimilarsenssthathavemetallicballsins

9、idetheyarecalledtiltswitcheshowevertheyaremeprimitiveusuallytheycanonlytellifthedeviceisinclinedwithinsomerangenotnottheextentofinclination.Sofarwehaveanalyzedtheaccelerometeroutputonasingleaxisthisisallyoullgetwithasing

10、leaxisaccelerometers.Therealvalueoftriaxialaccelerometerscomesfromthefactthattheycandetectinertialfcesonallthreeaxes.Letsgobacktoourboxmodelletsrotatethebox45degreestotheright.Theballwilltouch2wallsnow:ZXasshowninthepict

11、urebelow:在這種情況下盒子沒有移動但我們?nèi)稳蛔x取到Z軸有1g的值。球在墻壁上施加的壓力是由引力造成的。在理論上，它可以是不同類型的力量例如，你可以想象我們的球是鐵質(zhì)的，將一個磁鐵放在盒子旁邊那球就會撞上另一面墻。引用這個例子只是為了說明加速度計的本質(zhì)是檢測力而非加速度。只是加速度所引起的慣性力正好能被加速度計的檢測裝置所捕獲。雖然這個模型并非一個MEMS傳感器的真實構造，但它用來解決與加速度計相關的問題相當有效。實際上有些類似傳