Abstract
This paper proposes a measurement system using accelerometers in sports, which accurately measures the rotation motion. The accelerometer detects centrifugal acceleration, angular acceleration, linear acceleration and gravitational acceleration. A pair of accelerometers that lie on the same line detects same linear acceleration and same gravitational acceleration. Therefore linear acceleration and gravitational acceleration cancel each other by subtracting the two accelerometer signals, and the remainder is angular velocity (centrifugal acceleration) and angular acceleration. This measurement system uses the Kalman filter which uses the angular velocity and angular acceleration as observation signal. The accuracy of this method was examined by simulation and experiments.
