Method for determining the angular position of an electronic module fixed to the inner face of the tread of a tire

摘要

An angular position is determined for an electronic module fixed to the inner face of the tread of a tire fitted to a wheel of a vehicle. A sensor for measuring the radial acceleration of the wheel is integrated into the electronic module, and a variation of the radial acceleration is detected that corresponds to a position of the electronic module when it contacts the ground. This variation is used to determine a frame of reference defined by an origin and a reference unit corresponding to an angular sector of the tire having a length is shorter than a mean length of the footprint of the grounded tire, in order to determine angular positions of the electronic module in the frame of reference.

主权项

1. A method for determining, during rotation of a wheel (2) of a vehicle (1) fitted with a tire (4), an angular position of an electronic module (5) fixed to an inner face of the tread (4a) of said tire, comprising:
integrating a sensor (12) that measures a radial acceleration of the wheel (2) into the electronic module (5); making, by way of the sensor, at least one measurement of the radial acceleration, and using a value based on the at least one measurement to determine a value of a period (T) of revolution of the wheel (2); after the determining of the period (T) of revolution of the wheel (2), determining a sampling period by dividing the period (T) of revolution of the wheel (2) by a predetermined sampling rate (x), performing a plurality of measurements of the radial acceleration of the wheel (2) according to the determined sampling period, and detecting a variation of the plurality of measurements, the variation representative of a position of the electronic module (5) when a portion of the tire (4), upon which the electronic module (5) is affixed, is being in contact with the ground; determining the position of the electronic module (5) to be a location on the tire in which the variation of the radial acceleration is detected, and defining an origin sector (So) in terms of the determined position of the electronic module (5) on the tire when the tire is in contact with the ground and a reference unit of the tire formed by an angular unit sector (Su), the angular unit sector (Su) having a length that is shorter than a mean length of a footprint (Lfp) of the tire (4) on the ground, the footprint determined as a length between a falling edge and rising edge of the tire, the falling edge and rising edge determined by the variation of the radial acceleration detected from the electronic module (5) taking place when the portion of the tire upon which the electronic module (5) is affixed is in direct contact with the ground; and determining angular positions of the electronic module (5) inside a frame of reference defined by the origin sector (So), wherein the length of the origin sector (So) is the same length as the angular unit sector (Su), and the length of the angular unit sector (Su) is equal to the length rotated by the wheel (2) during the sampling period.