A measurement of sport wheelchair propulsion based on AHRS

Abstract

In this paper, we propose a novel Attitude and Heading Reference System (AHRS) based analysis method for sport wheelchair propulsion. Wireless inertial measurement units were attached to each wheel and an AHRS calculation was used to obtain the rotation angle of the sensors. The sensor rotation angle from the AHRS contains both the wheel rotation angle and the wheelchair turn angle in the horizontal plane. A coordinate system conversion from global coordinates to viewing coordinates was required to extract the wheel rotation angle. Both the distance travelled and the velocity were calculated using the angle. Four different trials were performed with two inertial sensors on each wheel. Straight-line distance tests gave high agreement among four sensors (28.164±0.028m). The difference between two sensors on the same wheel did not increase even for trials over 10 minutes, which implies a reduction in the effect of gyroscope drift. The velocity curves demonstrate agreement for acceleration and deceleration accompanied by push and traveling resistance.