Method and device for monitoring data relating to the tires of a vehicle

摘要

In a method for determining identifiers of wheel units and positions relative to the vehicle of the wheels on which the wheel units are fitted, the vehicle is equipped with a speed sensor for each wheel and elements for transmitting at a predetermined angular position of the corresponding wheel about its axis a message including the identifier of the wheel unit. A central processing unit receives the message and information from the speed sensors. The method includes a) counting, for each identifier, of a number “nt” of receptions of the identifier, b) statistical processing of the numbers “nt” to determine candidate identifiers of a wheel unit of the vehicle, until the number of candidate identifiers at least equals the number of wheels, and c) determining that a candidate identifier is the identifier of a wheel unit if the candidate identifier meets a predetermined criterion.

主权项

1. A method for determining identifiers (ID) of wheel units of a vehicle and positions relative to the vehicle of the wheels on which said wheel units are fitted, the vehicle being equipped with a speed sensor for each wheel, each wheel unit being equipped with means for transmitting at a predetermined angular position of the corresponding wheel around its axis (18) a message including the identifier of the wheel unit, a central processing unit receiving said message and information from said speed sensors, said method comprising the following steps:
a) counting, for each identifier, of a number “nt” of receptions of said identifier, b) statistical processing of the numbers “nt” in order to determine from among all the identifiers received those which are statistically indicated to be the identifier of one of the wheel units of the vehicle, the identifiers becoming candidate identifiers for the vehicle, the statistical process ending when the number of the candidate identifiers is at least equal to the number of wheels of the vehicle, and c) determining that each candidate identifier is the identifier of a particular wheel unit if said candidate identifier meets a predetermined criterion relating to at least one instant of reception of said candidate identifier and to the angular position of a particular wheel at said instant, and assigning to the corresponding particular wheel the position relative to the vehicle of the speed sensor supplying said angular position,wherein step c) comprises steps cb1) to cb10), in which
at step cb1), for each identifier received, a check is made as to whether or not said current received identifier is the candidate identifier; if not, the current received identifier is not processed, if yes in step cb1), at step cb2), an angular position of each wheel is determined for the instant at which the current candidate identifier was received, and an angular division of a full interval, −180° to +180°, is consequently selected for each wheel, at step cb3), a count of each selected division is incremented by one in the division of each wheel, the count being dedicated to the current candidate identifier, at step cb4), a dispersion value σ1, σ2, σ3, σ4 is calculated for each of the constructed histograms by counting the number of identifiers registered in a division, at step cb5), a ratio R is established between the first and the second smallest dispersion value for the current identifier, at step cb6), the ratio R is compared with a threshold value, at step cb7), if R is equal to or greater than the threshold value, the current candidate identifier is considered to be the identifier of the vehicle and the wheel unit responding to said current candidate identifier is positioned at the position corresponding to the smallest dispersion; if the ratio is not equal to or greater than the threshold value, the process continues, at step cb8), when it has been decided that the current identifier is the identifier of the vehicle, the current identifier is eliminated from the candidate identifiers, at step cb9), a check is made as to whether or not the four wheels have been learnt and positioned; if not, the process continues for the candidate identifiers which have not yet been eliminated as being the identifier of the vehicle and for the wheels which have not yet been located; if yes, the process is terminated, and at step cb10), if the process is not terminated at the end of a predetermined duration starting at the end of step b), the process has failed.