ium使用指南 2

1、AGuideGuideToTousingusingIMUIMU(Accelerometer(AccelerometerGyroscopeGyroscopeDevices)Devices)ininEmbeddedEmbeddedApplications.Applications.在嵌入式應(yīng)用中使用在嵌入式應(yīng)用中使用IMUIMU（加速度計(jì)和陀螺儀的設(shè)備）指南。（加速度計(jì)和陀螺儀的設(shè)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(jì)加速度計(jì)Tounderstthisunitwellstartwiththeaccelerometer.Whenthinkingaboutaccelerometersitisoftenusefultoimageaboxinshapeofacubewithaballinsideit.Youmayimaginesomethingelselikeacookieadonutbu

3、tIllimagineaball:要了解這個(gè)模塊我們先從加速度計(jì)開始。當(dāng)我們?cè)谙胂笠粋€(gè)加速度計(jì)的時(shí)候我們可以把它想作一個(gè)圓球在一個(gè)方盒子中。你可能會(huì)把它想作一個(gè)餅干或者甜圈，但我就把它當(dāng)做一個(gè)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(dòng)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(gè)磁鐵放在盒子旁邊那球就會(huì)撞上另一面墻。引用這個(gè)例子只是為了說(shuō)明加速度計(jì)的本質(zhì)是檢測(cè)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(jì)的檢測(cè)裝置所捕獲。雖然這個(gè)模型并非一個(gè)MEMS傳感器的真實(shí)構(gòu)造，但它用來(lái)解決與加速度計(jì)相關(guān)的問題相當(dāng)有效。實(shí)際上有些類似傳