用加速度計(jì)進(jìn)行傾斜傳感

　　當(dāng)用戶旋轉(zhuǎn)手機(jī)時(shí)，手機(jī)通常會(huì)改變屏幕方向。本文討論了將加速度計(jì)的輸出轉(zhuǎn)換為傾角的基本原理和所需的計(jì)算。

　　確定系統(tǒng)傾斜或傾斜的一種常用方法是將陀螺儀的輸出集成起來(lái)。雖然這種方法很簡(jiǎn)單，但隨著積分周期的增加，與零偏置穩(wěn)定性相關(guān)的錯(cuò)誤也可以迅速地合成，即使在設(shè)備靜止時(shí)也會(huì)引起明顯的旋轉(zhuǎn)。

　　在某些應(yīng)用中，隨著時(shí)間的推移，系統(tǒng)上的凈加速度或力是重力，加速度計(jì)可以用來(lái)測(cè)量?jī)A斜或傾斜的靜態(tài)角度。這些應(yīng)用包括游戲、數(shù)碼相機(jī)中的地平線檢測(cè)以及在工業(yè)和醫(yī)療應(yīng)用中檢測(cè)設(shè)備的標(biāo)題。

　　加速度計(jì)傾斜傳感的基本假設(shè)是，唯一的加速度刺激是與重力有關(guān)的。實(shí)際上，可以對(duì)信號(hào)輸出執(zhí)行信號(hào)處理，以去除輸出信號(hào)中的高頻內(nèi)容，因此可以容忍一些交流加速度。

　　Inclination sensing uses the gravity vector， and its projection on the axes of the accelerometer， to determine the tilt angle. Because gravity is a DC acceleration， any forces that result in an additional DC acceleration corrupt the output signal and result in an incorrect calculation. Sources of DC acceleration include the period of time when a vehicle is accelerating at a constant rate and rotating devices that induce a centripetal acceleration on the accelerometer. In addition， rotating an accelerometer through gravity causes an apparent AC acceleration as the projection of gravity on the axes of interest changes. Any filtering of the acceleration signal before calculating the inclination affects how quickly the output settles to the new static value.

　　This article discusses the basic principles for converting the output of an accelerometer to an angle of inclination. This discussion includes how to calculate the ideal inclination angle for a single-axis， dual-axis， or triple-axis solution. In addition， some basic information about calibration is included to reduce error from offset and sensitivity mismatch.