Method and system for monitoring a status of a tyre

A system for monitoring a status of a tyre fitted on a vehicle, the system comprising:

• a motion sensor fixed at a crown portion of the tyre and which detects a motion of the crown portion of the tyre;
• at least one processing unit in communication with the motion sensor and programmed to:
• with the vehicle in motion and the tyre in rotation, acquire a motion signal representative of a motion of a crown portion of the tyre, wherein the motion signal temporally corresponds to a plurality of turns of the tyre;
• filter from the motion signal a part of the motion signal temporally corresponding at least to each passage of the crown portion in a footprint area of the tyre, for obtaining a filtered motion signal;
• obtain a frequency spectrum of the filtered motion signal;
• and
• determine the status of the tyre based on the frequency spectrum
• wherein the motion sensor comprises an accelerometric sensor structured for detecting a component of a linear acceleration undergone by the crown portion of the tyre, wherein the motion sensor is fixed at a portion of inner surface of the tyre belonging to the crown portion of the tyre, wherein the system for monitoring the status of the tyre comprises:
• a speed sensor mounted onto the vehicle for detecting a forward speed of the vehicle, wherein the speed sensor is connected to the at least one processing unit;
• and
• an acceleration sensor mounted onto the vehicle for detecting a longitudinal acceleration of the vehicle, or a lateral acceleration of the vehicle, or a longitudinal acceleration of the vehicle and a lateral acceleration of the vehicle, wherein the acceleration sensor is connected to the at least one processing unit,
• wherein the at least one processing unit is programmed for carrying out a method for monitoring a status of a tyre fitted on a vehicle.

A method for monitoring a status of a tyre fitted on a vehicle, the method comprising:

• with the vehicle in motion and the tyre in rotation, acquiring a motion signal representative of a motion of a crown portion of the tyre, wherein the motion signal temporally corresponds to a plurality of turns of the tyre;
• filtering from the motion signal a part of the motion signal temporally corresponding at least to each passage of the crown portion in a footprint area of the tyre, for obtaining a filtered motion signal;
• obtaining a frequency spectrum of the filtered motion signal;
• and
• determining the status of the tyre based on the frequency spectrum
• wherein determining the status of the tyre comprises determining a status of wear of the tyre by:
• determining a reference modal mass of the tyre in a reference status, wherein the reference modal mass is greater than or equal to 60% of a total mass of the tyre, or less than or equal to 85% of a total mass of the tyre when new, or greater than or equal to 60% and less than or equal to 85% of a total mass of the tyre;
• determining a reference modal stiffness of the tyre in the reference status as a function of the reference modal mass of the tyre and of the frequency of the determined peak determined with the tyre in the reference status;
• and
• determining a thickness of a tread of the tyre as a function of the reference modal mass, the reference modal stiffness, the frequency of the determined peak, and as a function of physical and geometric parameters of the tyre,
• wherein the reference status is a status of undamaged and not worn tyre, and wherein the method further comprises determining the reference status when the vehicle has travelled a distance greater than or equal to 300 km and less than or equal to 1000 km since when the tyre in a new status is fitted.