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Absolute angle measurement using the earth-field-referenced hall effect sensors
P T Kolen1, J P Rhode, P R Francis
1Electrical and Computer Engineering Department, San Diego State University, CA 92182.
Journal of Biomechanics
|March 1, 1993
Summary
This study introduces a novel miniaturized absolute angle sensor using Earth's magnetic field. It offers high accuracy and immunity to errors for applications like joint rotation measurement.
Area of Science:
- Physics
- Engineering
- Biomedical Devices
Background:
- Traditional angle sensors often suffer from B-field and temperature-induced errors.
- Miniaturization and high accuracy are critical for advanced sensing applications.
Purpose of the Study:
- To develop a miniaturized absolute angle sensor with high immunity to environmental errors.
- To demonstrate the sensor's efficacy in measuring joint rotation.
Main Methods:
- Utilized Hall generators referenced to Earth's magnetic field for self-normalization.
- Implemented low-noise design and thermal compensation techniques.
- Tested the sensor's performance using shoulder joint rotation measurement.
Main Results:
- Achieved a sensor bandwidth of DC to 100 Hz with a 44.5 dB signal-to-noise ratio.
- Measured a maximum angular resolution of +/- 0.27 degrees.
- Demonstrated less than 2% temperature-induced error between 25°C and 40°C.
Conclusions:
- The developed Hall effect sensor provides accurate, self-normalized angle measurements.
- The sensor exhibits high immunity to B-field and temperature variations.
- Excellent agreement between theoretical and experimental results validates the sensor for biomechanical applications.