| 摘要 |
<p>A TPMS device 106 comprises a pair of accelerometers (103) fitted to a tyre (101) such that one accelerometer (103) measures a tangential component of acceleration as the tyre (101) rotates and the other accelerometer (103) measures a radial component of acceleration as the tyre (101) rotates. As the orientation of the two accelerometers (103) relative to gravitational acceleration varies when the tyre (101) rotates, the measured components of tangential and radial acceleration will vary as the tyre (101) rotates. By considering the relative phase between the maxima and minima measured by each accelerometer (103) it is possible to determine the direction of rotation of the tyre (101). Additionally, by considering the time separation between successive maxima it is possible to determine the rotation rate of the tyre (101). Integration of the determined rotation rate over time can determine the distance traveled by each tyre (101). Furthermore, by considering the direction of rotation it is possible to determine whether the wheel (102) to which the tyre (101) (and hence the TPMS 106) is mounted is provided on the left or right of the vehicle and to determine whether or not the wheel (102) is a steered wheel.</p> |
