用加速度計進行傾斜傳感

　　用加速度計進行傾斜傳感

　　當用戶旋轉(zhuǎn)手機時，手機通常會改變屏幕方向。本文討論了將加速度計的輸出轉(zhuǎn)換為傾角的基本原理和所需的計算。

　　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。雖然這種方法很簡單，但隨著積分周期的增加，與零偏置穩(wěn)定性相關(guān)的錯誤也可以迅速地合成，即使在設備靜止時也會引起明顯的旋轉(zhuǎn)。

　　在某些應用中，隨著時間的推移，系統(tǒng)上的凈加速度或力是重力，加速度計可以用來測量傾斜或傾斜的靜態(tài)角度。這些應用包括游戲、數(shù)碼相機中的地平線檢測以及在工業(yè)和醫(yī)療應用中檢測設備的標題。

　　加速度計傾斜傳感的基本假設是，唯一的加速度刺激是與重力有關(guān)的。實際上，可以對信號輸出執(zhí)行信號處理，以去除輸出信號中的高頻內(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.