多軸慣性量測系統的設計與實現

Design and Implementation of a Multi-axis Inertial Measurement Unit

何啟瑋(Chi-Wei Ho)

指導教授 ： 林沛群

國立臺灣大學/工學院/機械工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.00805

摘要

本論文主要探討九軸與十二軸兩種新式慣性量測系統（IMU，Inertial Measurement Unit）的設計與特性分析，兩個系統僅需經由簡單的代數運算便可同時得到系統質心（COM）的線加速度、角加速度以及角速度，不需複雜且容易造成訊號失真的微分或積分程序。
相較於由三軸加速規（accelerometer，量測線加速度）與三軸陀螺儀（gyro，量測角速度）所構成的傳統六軸慣性量測系統，本論文中九軸系統是由六軸加速規與三軸陀螺儀所構成，這樣的設計提供兩個優點：一為免除了在傳統系統中需將三軸加速規裝在系統質心（COM）的限制，另一為系統也同時提供角加速度的資訊。而本論文中十二軸系統是由十二軸加速規所構成，該系統除了具備了前述九軸系統述的兩個優點之外，也因為並不需要安裝任何陀螺儀，間接免除了現今陀螺儀不易校正、訊號容易飽和以及成本較高等問題，也使機電系統在設計與維護上更趨簡單，代價為角速度訊號需經過演算得出，不像其它系統可由陀螺儀直接量測。
由於系統對於感測元件之位置並無限制，本論文對於安裝位置之最佳化有進行探討，並分析安裝位置誤差與安裝角度誤差所造成之影響，對於角度誤差並開發校正程序以減低其影響。同時，並探討軸數多於九軸與十二軸的冗餘（redundant）系統之特性。本論文中並開發單自由度旋轉實驗平台，分別以等速與諧波驅動兩種軌跡，以電壓驅動馬達與位置控制等兩個方式，對偏心系統產生相對應的線加速度、角加速度與角速度，實際以實驗結果來探討九軸與十二軸系統的運作特性。

關鍵字

慣性量測系統 ； 加速規 ； 陀螺儀 ； 線加速度角加速度角速度

並列摘要

This thesis is focused on the design and analysis of a 9-axis and a 12-axis multi-axis
Inertial Measurement Units (IMU). Both systems are capable of deriving linear
acceleration, angular acceleration and angular velocity via simple linear algebra without
any complicate differentiation or integration process.
Comparing with the traditional IMU comprised of 3-axis accelerometers (measuring
acceleration) and 3-axis gyros (measuring angular velocity), the proposed 9-axis IMU is
comprised of 6-axis accelerometers and 3-axis gyros. The system has two advantages:
first, it doesn't require accelerometer installation at the center of mass (COM) as in the
traditional 6-axis IMU; second, it is capable of delivering angular acceleration
simultaneously.
The proposed 12-axis IMU is comprised of 12-axis accelerometers. The system not
only has the two advantages shown in the 9-axis system, but also simplifies design and
maintenance of the mechatronic system due to its solo use of low-cost accelerometers
but no gyros which are difficult to calibrate, easy to saturate, and with higher price.
The trade-off is the derivation of angular velocity through algorithm, not directly from gyro readings.
The thesis includes the optimization of sensor allocation, the error analysis of sensor positions and orientations, and the calibration procedure to reduce the effect of orientation errors. In addition, the thesis includes the discussion of redundant systems (more than 12-axis). An bench-top apparatus with one rotational degree of freedom is developed as well and is utilized as the experimental platform to evaluate the performance of the proposed systems.

並列關鍵字

IMU ； accelerometer ； gyro ； linear acceleration ； angular acceleration ； angular velocity

參考文獻

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