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Published on: May 8, 2014
Dynamic accuracy of inertial measurement units during simple pendulum motion
M A Brodie1, A Walmsley, W Page
1Massey University, Wellington, New Zealand. m.a.brodie@mssey.ac.nz
Summary
Inertial measurement units (IMUs) show potential for motion capture, but vendor algorithms yield high orientation errors. A custom fusion algorithm significantly improved IMU accuracy for pendulum motion tracking.
Area of Science:
- Biomechanics
- Robotics
- Sensor Technology
Background:
- Inertial measurement units (IMUs) offer a potential alternative to traditional video motion capture systems.
- IMUs integrate accelerometers, magnetometers, and gyroscopes for motion tracking.
- Assessing the accuracy of IMUs in estimating 3D orientation is crucial for their adoption.
Purpose of the Study:
- To evaluate the accuracy of IMUs in measuring 3D orientation during simple pendulum motion.
- To compare the performance of a vendor-supplied Kalman filter algorithm against a custom fusion algorithm.
- To validate IMU accuracy claims against a video motion capture reference system.
Main Methods:
- Pendulum motion was simultaneously recorded using IMUs and a video motion capture system.
- IMU raw data were processed using both the vendor's Kalman filter and a custom fusion algorithm.
- Root Mean Squared (RMS) error was calculated to quantify orientation estimation accuracy.
Main Results:
- The vendor's Kalman filter algorithm resulted in RMS errors between 8.5 and 11.7 degrees, significantly deviating from video capture.
- Maximum orientation errors exceeding 30 degrees were observed with the vendor's algorithm.
- The custom fusion algorithm achieved a high level of accuracy, with RMS errors ranging from 0.8 to 1.3 degrees.
Conclusions:
- Vendor-supplied algorithms for IMUs may not provide sufficient accuracy for precise motion analysis.
- Custom fusion algorithms demonstrate superior performance in estimating 3D orientation from IMU data.
- Further development of general-purpose fusion algorithms and transparent error reporting by vendors is recommended.
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