EP2897816A1

EP2897816A1 - Method for locating the position of wheels which are fitted with an electronic unit incorporating means of measuring an operating parameter of said wheel

Info

Publication number: EP2897816A1
Application number: EP13758747.3A
Authority: EP
Inventors: Nicolas Guinart
Original assignee: Continental Automotive GmbH; Continental Automotive France SAS
Current assignee: Continental Automotive GmbH; Continental Automotive France SAS
Priority date: 2012-09-21
Filing date: 2013-08-29
Publication date: 2015-07-29
Also published as: US9759557B2; CN104640719B; FR2995991B1; WO2014044355A1; US20150233711A1; WO2014044355A8; CN104640719A; FR2995991A1

Abstract

The invention relates to a method for locating the position of wheels (5-8) of a vehicle (V) comprising, mounted on each wheel, an electronic unit (1-4) incorporating measurement means (9) for measuring a predetermined operating parameter for said wheel, referred to as a location parameter and, assigned to each wheel position and mounted on the vehicle (V), fixed means (13-16) for measuring the location parameter for said wheel. This location method consists, firstly, for each electronic unit (1-4), in comparing the values measured by the mobile measurement means (9) incorporated into said electronic unit with those measured by each of the fixed measurement means (13-16), secondly, for each wheel position, comparing the values measured by the fixed measurement means (13-16) assigned to said wheel position with those measured by each of the mobile measurement means (9), then assigning a wheel position to an electronic unit (1-4) when these correspond with one another.

Description

A method of locating the position of wheels equipped with an electronic box incorporating means for measuring an operating parameter of said wheel

The invention relates to a method for locating the position of wheels equipped with an electronic box incorporating means for measuring an operating parameter of said wheel, mounted on a vehicle comprising means for measuring this parameter.

More and more motor vehicles have, for security purposes, surveillance systems comprising sensors mounted on each of the wheels of the vehicle, dedicated to the measurement of parameters, such as pressure or temperature, of tires fitted to these wheels, and intended to inform the driver of any abnormal variation of the measured parameter.

These surveillance systems are conventionally equipped with an electronic box mounted on each of the wheels of the vehicle, integrating, in addition to the aforementioned sensors, a microprocessor and a radiofrequency transmitter, and a central unit for receiving the signals emitted by the transmitters, comprising a computer integrating a radio frequency receiver connected to an antenna.

One of the problems that such monitoring systems need to solve lies in the obligation of having to associate with each signal received by the central unit, information concerning the location of the electronic box and thus of the wheel at the origin of this signal. , this obligation lasting for the life of the vehicle, ie to be respected even after wheel changes or simply inversions of the position of these wheels.

Many methods are currently proposed for this location of the position of the wheels of a vehicle, including location methods, such as in particular described in patents EP 0 806 306 and EP 0 895 879, the concept is based on on the correlation existing between the signals delivered by a sensor fitted to a wheel and the signals delivered by a sensor mounted on the vehicle in the vicinity of this wheel.

Most current vehicles being equipped with active safety systems such as ABS anti-lock system, ESP system for dynamic stability control, such methods of location are particularly important in terms of cost of ownership. installation, because the location of the wheels is effected by correlation of the signals delivered by the sensors of said active safety system and signals delivered by the sensors usually integrated in the electronic boxes of the monitoring system. Therefore, the implementation of these location methods simply requires the implementation of a signal processing software delivered but does not require any additional hardware.

The present invention also aims at a method of localization based on this correlation principle and its primary objective is to provide such a very efficient locating method in terms of responsiveness and reliability.

For this purpose, the invention provides a method for locating the position of wheels of a vehicle comprising:

r wheels each equipped with an electronic unit incorporating means, said mobile, measuring a predetermined parameter of operation of said wheel, said location parameter, and a transmitter for the transmission of signals comprising data representative of measured values of said location parameter and an identification code of said electronic box,

- assigned to each wheel position and mounted on the vehicle, r means, said fixed, measuring the location parameter of said wheel,

and mounted on the vehicle, a central unit provided with means for receiving, on the one hand, signals coming from the electronic boxes, and, on the other hand, data representative of the values measured by the fixed measurement means,

said locating method consisting of studying the correlation between the values measured by the fixed measuring means and those measured by the mobile measuring means, in order to assign a wheel position to each electronic box.

According to the invention, this location method is characterized in that:

for each electronic unit, the data representative of the values measured by the mobile measurement means integrated in said electronic box, and those measured by each of the fixed measuring means, are compared and the correlation between said data is studied. to establish a correspondence between an electronic box and a wheel position,

for each wheel position, the data representative of the values measured by the fixed measuring means assigned to said wheel position and those measured by each of the moving measuring means integrated in the electronic boxes are compared and the correlation between said data so as to establish a correspondence between a wheel position and an electronic box, a wheel position is assigned to an electronic box during a mutual correspondence between said wheel position and said electronic box.

The locating method according to the invention therefore consists in finding, on the one hand, the "preferred" wheel position of each electronic unit, and on the other hand, the "preferred" electronic unit of each wheel position, in order to establish cross correlations between said electronic boxes and said wheel positions.

In practice, such a decision procedure, the implementation of which is very simple and easy, allows on average a convergence of at least 30% to 40% faster than that achieved by the implementation of the current procedures, this saving of time can even reach 70% in the best cases.

Consequently, this localization method leads to a significant increase in the performance and the robustness of the system which offer considerable margins of maneuver in the definition of said system.

In addition, the locating method can also make it possible to learn the electronic units fitted to the wheels actually mounted on the vehicle. For this purpose, advantageously according to the invention, for each electronic unit, a value representative of the sum of the representative values of the dispersion obtained for each of the wheel positions is determined, this sum value is compared with a predetermined threshold value. , and excludes the electronic box of the location procedure if this sum-value is lower than said threshold.

According to an advantageous embodiment of the method according to the invention, it is determined, with a view to studying the correlations, data, such as for example the variance, representative of the dispersion of the values measured by the mobile measuring means by to the values measured by the fixed measuring means.

Moreover, in order to study the correlations, it is advantageous to determine, according to the invention, for each pair of electronic box / wheel position, a datum representative of the so-called overall ratio of the weight of the dispersion of the values measured by said box. electronics compared to the weights of the dispersions of the values measured by each of the other electronic boxes.

In addition, for the purpose of determining each overall ratio, it is advantageous to calculate, according to the invention, first of all, for each pair of electronic control unit / wheel position, unit ratios each corresponding to the ratio of the weight of the dispersion of the measured values. by said electronic box with respect to the weight of the dispersion of the values measured by each of the other electronic boxes, and the product of the unit ratios is carried out in order to determine the overall ratio. The value of each unit ratio is, moreover, advantageously adjusted as a function of the number of "processed" signals with a view to its determination, and to this end, a threshold number of signals coming from each box is advantageously defined according to the invention. below which the value of the unit ratios is corrected by a weighting factor of increasing value with the number of signals received.

According to another advantageous embodiment of the process according to the invention, the following are calculated for correlations:

for each electronic unit, and for each wheel position, a characteristic value equal to the ratio of the overall ratio calculated for this wheel position, to the sum of all the overall ratios calculated for the different wheel positions,

for each wheel position, and for each of the electronic boxes, a characteristic value equal to the ratio of the overall ratio calculated for this electronic unit, to the sum of all the overall ratios calculated for the different electronic boxes.

In addition, the two specific characteristic values relating to the electronic control unit and to the wheel position are advantageously combined for each pair of electronic control unit / wheel position, so as to define a so-called combined characteristic value.

On this basis, the process according to the invention advantageously consists in calculating, with a view to correlations:

- for each control unit, and for each wheel position, a normalized characteristic value equal to the ratio of the combined characteristic value calculated for that wheel position, to the sum of all the combined characteristic values calculated for the different wheel positions,

- for each wheel position, and for each electronic unit, a normalized characteristic value equal to the ratio of the combined characteristic value calculated for this electronic unit, to the sum of all the combined characteristic values calculated for the different electronic boxes.

The last step of the procedure then consists, advantageously according to the invention, in comparing each normalized characteristic value with a predetermined threshold value, and in conferring a value representative of a correspondence with the electronic control unit / wheel position when the said characteristic value is greater than the threshold value. Other features and advantages of the invention will emerge from the detailed description which follows with reference to the accompanying drawings which show by way of non-limiting example a preferred embodiment. On these drawings:

- Figure 1 is a schematic top view of a vehicle with a monitoring system and an active safety system for implementing the method according to the invention for locating the position of the wheels of said vehicle ,

- Figure 2 is a schematic view of this vehicle on which are mentioned indications to explain the process implemented according to the invention.

The method according to the invention is adapted to be implemented with a view to locating the position of the wheels of a vehicle V as represented in FIG. 1, equipped with four wheels 5-8 and equipped with a control system. monitoring of parameters, such as pressure and / or temperature, of tires, and an active safety system such as anti-lock ABS "ABS" system or "ESP" dynamic stability control system.

In the usual way, the surveillance system conventionally comprises, firstly, associated with each wheel 5-8, an electronic box 1-4, for example secured to the rim of said wheel so as to be positioned inside the housing. the tire envelope.

Each of these electronic boxes 1-4 includes sensors dedicated to the measurement of tire parameters, connected to a microprocessor-based calculation unit connected to a transmitter 10.

Each of these electronic boxes 1 -4 also includes, in a conventional manner, measuring means 9 of the angular position of said electronic box. Such measuring means may advantageously consist of an accelerometer capable of supplying modulated signals representative of the values of the gravity and therefore of the angular position of the electronic unit, whose frequency, equal to the frequency of rotation of the wheels, makes it possible, moreover, , to calculate the speed of rotation of said wheels.

The monitoring system also comprises a central unit 1 1 located in the vehicle V, comprising a microprocessor and integrating a receiver 12 able to receive the signals emitted by the transmitters 10 of each of the four electronic boxes 1-4.

The V vehicle is also equipped with an active safety system such as ABS anti-lock system, ESP system for dynamic stability control, with four 13-16 wheel speed sensors positioned on the vehicle. V, each near a wheel 5-8, and adapted to provide, data representative of the speed of rotation of said wheel.

In addition, this active safety system comprises an "ABS" or "ESP" computer 17 connected to the various wheel speed sensors 13-16, so as to receive the wheel speed information measured by said sensors, and programmed to Anticipate regulations to prevent wheel lock 5-8.

Usually, the wheel speed sensors 13-16 consist of inductive, magneto-resistive or Hall effect sensors adapted to measure the speed of each wheel 5-8 on a toothed or magnetic wheel.

For the purpose of locating each wheel 5-8 of the vehicle V, the method according to the invention consists in using the data supplied by the accelerometers 9 and sensors 13-16, according to the method described below.

In the first place, the electronic boxes 1-4 equipping the wheels 5-8, deliver a plurality of signals for predetermined angular positions of said electronic boxes.

The transmission period of these signals is of the order of several seconds, generally 15 to 20 seconds, in view of a part of the respect of the radiofrequency standards, and secondly, to allow a sufficient "desynchronization" of the wheels 5-8.

Meanwhile, the sensors 13-16 deliver to the computer 17 data representative of the orientation of the associated wheels 5-8, in the form of values convertible into angular values (tooth number of the toothed wheel ...).

As it is an active safety system, the transmission period of these signals is significantly lower than that of the electronic boxes 5-8, for example of the order of 10 ms to 20 ms.

The localization method implemented according to the invention is described below with the support of numerical tables representative of values successively obtained during the steps of this localization method.

The first step of this localization process consists in:

for each electronic box 1-4, by correlation between the data provided by the accelerometer 9 and those provided by the sensors 13-16, four distributions per electronic box 1 -4, namely a distribution for each wheel position 5 -8,

- calculate, for each of the distributions, a value representative of the dispersion of said distribution, consisting in the example in the variance of this distribution. These variances are represented in the tables below (which represent the actual values of each variance (Table 1)) and then the rounded values of each variance (Table 2), in which:

Nb represents the number of signals from each electronic control unit 1-4, on the basis of which the calculation of the variance has been carried out,

Vi represents the variance obtained for the control unit (i) with i = 1 to 4, respectively for the left front position (FL), the right front position (FR), the right rear position (RR) and the left rear position (RL).

Table 1: Variances (real values)

Table 2: Variances (rounded values)

The following step illustrated in Table 3 below consists in calculating, for each pair of electronic box 1-4 / wheel position 5-8, unit ratios lij = Vj / Vi, represented in FIG. 2, each corresponding to the ratio of the weight of the dispersion of the values measured by said electronic box with respect to the weight of the dispersion of the values measured by each of the other electronic boxes.

Table 3: Unit ratios lij

These values lij are then corrected by a weighting coefficient function of the number Nb of signals from each electronic box 1-4, the basis of which the calculation of the variance has been carried out. This weighting coefficient is designed so that the influence of these values lij is proportional to the number Nb of signals received, and these values being intended to be multiplied with each other, as described in the following step, the goal is to bring them together. the neutral value, equal to 1 for a product, when the number Nb of signals is small.

For example, this weighting coefficient may vary between a value

Cp equal to 0% for Nb <2, and a value Cp equal to 100% for Nb> 10, with for example an intermediate value Cp of 60% for Nb = 7

Moreover, on the basis of these values Cp of weighting coefficients, the value lij retained is equal to:

- Cp% (lij - 1) when lij≥ 1,

- 1 - (Cp% (1 - lij)) when lij <1.

In the numerical example present, the number Nb of received signals is equal to 15 for each electronic control unit 1-4, and the weighting coefficient is therefore 100% and therefore inoperative with respect to the calculated values cij.

The next step is to calculate, for each pair of electronic box

1-4 / 5-8 wheel position, a data representative of the ratio, said overall, of the weight of the dispersion of the values measured by said electronic box with respect to the weight of the dispersions of the values measured by each of the other electronic boxes.

This calculation amounts to calculating, as represented in the table below, for each rank column i of a given electronic box, with i = 1 to 4, the product fl lij, with j = 1 to 4 and j ≠ i

In particular, the values of column 1 (FL) correspond to the values 112 x 113 x 114, the values of column 2 (FR) correspond to the values 121 x I23 x I24 ...

It should be noted that the Iji values are equal to 1 / lij, so that the values lij provided in the table above suffice to calculate all the overall ratios.

As shown in Table 4 below, the maximum (MAX) of the overall ratios per line and column are further determined.

Table 4: Overall Ratio (rounded values)

ID \ POS Nb FL FR RR RL MAX

1_FL 15 11, 34 0.32 1, 24 0.22 1 1, 34

2_EN 15 0.3 19.76 0.71 0.23 19.76

3_RR 15 0.51 0.22 20.23 0.45 20.23

4_RL 15 0.11 2.43 0.1 35.52 35.52

MAX 1 1, 34 19.76 20.23 35.52 The following step consists in calculating, for each electronic control unit 1-4, and for each wheel position 5-8, a characteristic value consisting of a normalized ratio equal to the ratio of the overall ratio calculated for this wheel position. 8, on the MAX value of all the global ratios calculated for the different wheel positions (maximum value of the overall ratios per line of the table above)

The results of this step are shown in Table 5 below.

Table 5: Standard Ratio for Electronic Enclosures

Similarly, as shown in Table 6 below, for each wheel position 5-8, and for each of the electronic boxes 1-4, a characteristic value is calculated, consisting of a normalized ratio, equal to the ratio of the overall ratio calculated for this electronic box 1-4, on the MAX value of all the global ratios calculated for the various electronic boxes 1-4 (Maximum value (MAX) of the overall ratios per column of the table of overall ratios).

Table 6: Normalized Ratios for Wheel Position

The following step, the results of which are mentioned in table 7 below, consists in combining, for each pair of electronic box 1-4 / wheel position 5-8, the two specific characteristic values consisting of the normalized ratios respectively relative to the electronic unit 1 -4 and wheel position 5-8, so as to define a so-called combined characteristic value consisting of a combined normalized ratio. Table 7: Combined Standardized Ratios

The next step is to determine the answer to the following question: "What is the preferred 1-4 control unit for each position? "

For this purpose, a normalized characteristic value (table 8) equal to the ratio of the combined characteristic value calculated for this wheel position 5-8 (FIG. values in Table 7 above), on the sum of all the combined characteristic values calculated for the different wheel positions 5-8 (Sum of each row of the table above). Table 8: Standardized characteristic values for electronic enclosures

Similarly, the next step is to determine the answer to the following question: "What is the preferred position of each electronic box? "

For this purpose, for each wheel position 5-8, and for each electronic control unit 1-4, a normalized characteristic value (table 9) is calculated equal to the ratio of the combined characteristic value calculated for this control unit 1 -4, on the sum of all the combined characteristic values calculated for the different electronic boxes 1-4 (sum of each column in the combined standard ratios table), Table 9: Standardized characteristic values for the wheel position.

The following two steps, the results of which appear in the two tables (8,9) below, consist in comparing each of the values of the two previous tables with a predetermined threshold value, in the example at 0,9 and in conferring a value representative of a correspondence, in the example value equal to 1, to the electronic control unit 1-4 / wheel position 5-8 when said characteristic value is greater than the threshold value, and otherwise to confer a value representative of a non-correspondence, in the example value equal to 0.

Table 10: Comparison of electronic enclosures

Table 11: Comparison relating to the wheel position

The final step is, finally, to combine the results of the two tables above (Tables 10, 1 1) so as to check the possible presence of reciprocal correspondences represented by a combined value in the example equal to 2 (Table 12 ).

The locating procedure ends when at least three matches are obtained, the fourth match being deductible from the established matches. Table 12: Reciprocal Correspondence

In the example shown above (Table 12):

- The identifier 1 (wheel 5) is in the front left position,

The identifier 2 (wheel 6) is in the right front position, - the identifier 3 (wheel 7) is in the right rear position, and

- The identifier 4 (wheel 8) is in the left rear position.

Claims

1 / A method of locating the wheel position (5-8) of a vehicle (V) comprising:

r wheels (5-8) each equipped with an electronic box (1-4) incorporating means (9), said mobile, for measuring a predetermined parameter of operation of said wheel, said location parameter, and an emitter

(10) for the transmission of signals comprising data representative of the measured values of said location parameter and an identification code of said electronic box,

- assigned to each wheel position (5-8) and mounted on the vehicle (V), r means (13-16), said fixed, for measuring the location parameter of said wheel,

- and, mounted on the vehicle (V), a central unit (11) provided with receiving means (12), on the one hand, signals from the electronic boxes (1-4), and on the other hand, data representative of the values measured by the fixed measuring means (13-16),

said locating method consisting of studying the correlation between the values measured by the fixed measuring means (13-16) and those measured by the mobile measuring means (9), with a view to assigning a wheel position (5); -8) to each electronic box (1-4), and this method of localization being characterized in that:

for each electronic box (1-4), the data representing the values measured by the mobile measurement means (9) integrated in said electronic box and those measured by each of the fixed measuring means (13-16) are compared. ), and the correlation between said data is studied so as to establish a correspondence between an electronic box (1-4) and a wheel position (5-8),

for each wheel position (5-8), the data representative of the values measured by the fixed measuring means (13-16) assigned to said wheel position are compared with those measured by each of the moving measuring means. (9) integrated in the electronic boxes (1 -4), and the correlation between said data is studied so as to establish a correspondence between a wheel position (5-8) and an electronic box (1 -4), a wheel position (5-8) is assigned to an electronic box (1-4) during a reciprocal correspondence between said wheel position and said electronic box.

21 locating method according to claim 1 characterized in that, for the purpose of studying the correlations, data representative of the dispersion of the values measured by the mobile measuring means (9) with respect to the values measured by the fixed measuring means (13-16).

3 / A locating method according to claim 2 characterized in that, for each electronic box (1-4), a value representative of the sum of the representative values of the dispersion obtained for each of the wheel positions (5-8) is determined. this sum value is compared with a predetermined threshold value, and the control unit (1-4) of the localization procedure is excluded if this sum value is lower than said threshold.

4 / locating method according to one of claims 2 or 3 characterized in that it is determined, for the purpose of studying the correlations, for each pair of electronic box (1-4) / wheel position (5-8) , a data representative of the ratio, said overall, of the weight of the dispersion of the values measured by said electronic box with respect to the weight of the dispersions of the values measured by each of the other electronic boxes.

51 A locating method according to claim 4 characterized in that, for the purpose of determining each overall ratio, is calculated, first, for each pair of electronic box (1-4) / wheel position (5-8), unit ratios, each corresponding to the ratio of the weight of the dispersion of the values measured by said electronic box to the weight of the dispersion of the values measured by each of the other electronic boxes, and the product of the unit ratios is carried out in order to determine the overall ratio.

6 / A locating method according to claim 5 characterized in that one defines a threshold number of signals from each electronic box (1-4) below which the value of the unit ratios is corrected by a value weighting factor increasing with the number of signals received.

Method of localization according to one of Claims 5 or 6, characterized in that the correlations are calculated as follows:

for each electronic unit (1-4), and for each wheel position (5-8), a characteristic value equal to the ratio of the overall ratio calculated for this wheel position (5-8), on the sum of all the global ratios calculated for the different wheel positions,

for each wheel position (5-8), and for each of the electronic boxes (1-4), a characteristic value equal to the ratio of the overall ratio calculated for this electronic box (1-4), on the sum of all the global ratios calculated for the different electronic boxes (1-4).

8 / A locating method according to claim 7 characterized in that for each pair of electronic control unit (1-4) / wheel position (5-8), the two specific characteristic values respectively relating to the control unit (1) are combined. -4) and the wheel position (5-8), so as to define a so-called combined characteristic value.

9 / A method of locating according to claim 8 characterized in that one calculates, for correlations:

- for each control unit (1-4), and for each wheel position (5-8), a normalized characteristic value equal to the ratio of the combined characteristic value calculated for this wheel position (5-8), to the sum of all the combined characteristic values calculated for the different wheel positions (5-8),

- for each wheel position (5-8), and for each of the electronic boxes (1-4), a normalized characteristic value equal to the ratio of the combined characteristic value calculated for that electronic unit

(1-4), on the sum of all the combined characteristic values calculated for the different electronic boxes. (1-4).

10 / A locating method according to claim 9 characterized in that each normalized characteristic value is compared with a predetermined threshold value, and a value representative of a correspondence to the electronic control unit (1-4) / position pair is given. wheel (5-8) when said characteristic value is greater than the threshold value.