Method and equipment for monitoring tyre wear, and vehicle on-board wear-monitoring system

• US 10,286,735 B2
• Filed: 04/15/2015
• Issued: 05/14/2019
• Est. Priority Date: 04/18/2014
• Status: Active Grant

• Current Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Inventors: Guinart, Nicolas, Benbouhout, Rachid, Huard, Jean-Charles
• Primary Examiner(s): McGue, Frank J
• Application Number:
  US15/127,178
• Publication Number:
  US 20170096036A1
• Time in Patent Office: 1,490 Days
• Field of Search: 342 21
• CPC Class Codes: B60C 11/243 Tread wear sensors, e.g. electronic sensors
• CPC Class Codes: B60C 11/246 Tread wear monitoring systems
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: G01M 17/02 Tyres
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband

Abstract

A reliable and precise measurement of tire tread wear, by using wide-band (UWB) pulses and analyzing the signature obtained by reflection of these pulses from the tread, in order to deduce its state of wear therefrom. The tire wear monitoring device (100) includes a control unit (110) for signal control and data processing, this control unit (110) being coupled to a generator of ultra wide band or UWB signals (120), which is itself coupled to an antenna for incident UWB pulse transmission (140), and an antenna for receiving the UWB pulses (150) reflected from at least one interface of the tire tread, the reception antenna (150) being coupled to a pulse signal receiver (180) which is itself coupled to the control unit (110).

Claims

1. A method for monitoring the wear of a tread (10) of a vehicle tire (1), where the tread (10) has an inner layer (11) with an inner interface (11a), an intermediate layer incorporating at least one metal reinforcement interface (12, 13), and an outer layer (14) with an inner interface, which includes a groove bottom (14a), and a grooved outer interface (14b), the vehicle tire being capable of traveling while forming a contact patch (1E) of the grooved outer face (14b) on a road (2), the method comprising:

transmitting, from a source arranged near the vehicle tire (1), at least one wide band (UWB) incident pulse signal (i1) toward the outer layer (14) containing the contact patch (1E) of the vehicle tire (1) on the road (2);

receiving (31, 150, 310) pulses (iR1 to iR6) reflected by the interfaces (11a, 12, 13, 14a, 14b) of the tread (10) and by the road (2);

determining a wear signature of said tread by measuring relative delays exhibited by reflected pulses relative to an instant of transmission (t0) of the incident pulse (i1), said determined wear signature being defined based on the relative delays exhibited by at least one of the pulses (iR5, iR6) reflected by the road (2) and the grooved outer interface (14b), and the relative delays of the pulses (iR4;

iR2, iR3) reflected by at least one of the inner groove bottom interface (14a) and said at least one metal reinforcement interface (12, 13); and

triggering an alarm upon detection that the wear signature corresponds to a critical state of the tread (10) defined with respect to the predetermined risk of losses of adhesion of the contact patch (1E) of the vehicle tire (1) on the road (2).

2. The wear monitoring method as claimed in claim 1,

wherein the wear signature is regularly sampled from a plurality of successive incident pulses to produce a plurality of successively sampled wear signatures, and

wherein the successively sampled wear signatures are compared in order to determine a periodicity of transmission of the incident pulse signals based on a corresponding mileage.

3. The wear monitoring method as claimed in claim 2, further comprising at least one of:

comparing a relative delay exhibited by a pulse reflected by the grooved outer interface (14b) in an area outside the contact patch (1E) with the relative delays of the wear signature; and

analyzing tire load and pressure data supplied by a dedicated detection system, deducing corrections of the relative delays of the reflected pulses, and modifying the wear signature accordingly.

4. The wear monitoring method as claimed in claim 1, further comprising at least one of:

comparing a relative delay exhibited by a pulse reflected by the grooved outer interface (14b) in an area outside the contact patch (1E) with the relative delays of the wear signature; and

analyzing tire load and pressure data supplied by a dedicated detection system, deducing corrections of the relative delays of the reflected pulses, and modifying the wear signature accordingly.

5. A tire wear monitoring device (100, 100′

) for monitoring the wear of a tread (10) of a vehicle tire (1), where the tread has an inner layer (11) with an inner interface (11a), an intermediate layer incorporating at least one metal reinforcement interface (12, 13), and an outer layer (14) with an inner interface, which includes a groove bottom (14a), and a grooved outer interface (14b), the vehicle tire being capable of traveling while forming a contact patch (1E) of the grooved outer face (14b) on a road (2), comprising;

a control unit (110) for signal control and data processing;

a generator (120) of ultra wide band (UWB) signals (Se), said generator (120) coupled to said control unit (110);

one or more antennas configured to transmit incident UWB pulses and receive reflected UWB pulses (150) reflected from at least one interface of the tire tread; and

a pulse signal receiver (180), said pulse signal receiver (180) coupled to said control unit (110),

wherein said control unit is configured to

transmit, from the one or more antennas arranged near the vehicle tire (1), at least one wide band (UWB) incident pulse signal (i1) toward the outer layer (14) containing the contact patch (1E) of the vehicle tire (1) on the road (2),

receive, via the one or more antennas, pulses (iR1 to iR6) reflected by the interfaces (11a, 12, 13, 14a, 14b) of the tread (10) and by the road (2),

determine a wear signature of said tread by measuring relative delays exhibited by reflected pulses relative to an instant of transmission (t0) of the incident pulse (i1), said determined wear signature being defined based on the relative delays exhibited by at least one of the pulses (iR5, iR6) reflected by the road (2) and the grooved outer interface (14b), and the relative delays of the pulses (iR4;

iR2, iR3) reflected by at least one of the inner groove bottom interface (14a) and said at least one metal reinforcement interface (12, 13), and

trigger an alarm upon detection that the wear signature corresponds to a critical state of the tread (10) defined with respect to the predetermined risk of losses of adhesion of the contact patch (1E) of the vehicle tire (1) on the road (2).

6. The wear monitoring device as claimed in claim 5, wherein the one or more antennas comprise two separate antennas, a first of said two antennas configured for transmission (140) and a second of said two antennas configured for reception (150).

7. The wear monitoring device as claimed in claim 6, wherein the one or more antennas have unidirectional transmission means and directional reception means.

8. The wear monitoring device as claimed in claim 6,

wherein a pulse amplifier (130) is arranged between an output of the pulse signal generator (120) and the one or more antennas, and

wherein a filter assembly (160), coupled to a low-noise amplifier (170), is fitted between the one or more antennas and an input of the pulse signal receiver (180).

9. The wear monitoring device as claimed in claim 6, wherein:

the UWB pulse signal generator (120) comprises a digital-analog converter (DAC) (121) that converts an initial signal (s1) launched by the control unit (110) and modulated via a baseband transmission clock (122), said converter (121) being coupled to a mixer (124) via a filter (123) so that a modulated and filtered signal (Sa) carries a brief pulse of a radio frequency (RF) signal supplied by an RF oscillator (125), also under control of the control unit (110), a duration of the initial signal being adjusted so that a carried signal corresponds to a frequency spectrum with a width of at least 25% of the central frequency value of said frequency spectrum, before being amplified (130) and then transmitted by the transmission antenna (140) in the form of a UWB pulse signal; and

the UWB pulse signal receiver (180) comprises a mixer (181) coupled to an analog-digital converter/sampler (ADCS) (182), said ADCS being coupled to the control unit (110) and configured to perform sampling upon a reflected UWB pulse signal received from the one or more antennas and mixed, after filtering (160) and amplification (170), with an RF signal supplied by a local radio frequency oscillator (184) which is also under control of the control unit (110), the sampling being timed by a baseband clock (183) under control of the control unit (110), to supply a digital UWB pulse signal (Sn) to the control unit (110) corresponding to the reflected UWB pulse signal (Sr).

10. The wear monitoring device as claimed in claim 6, wherein the control unit (110) comprises a correlator (111) that correlates successive digital UWB pulse signals (Sn) supplied by an analog-digital converter/sampler (ADCS) (182) and forms successive wear signatures, said correlator (111) being coupled to a digital processing unit (112) to determine a state of wear of the tire on the basis of the successive wear signatures.

11. The wear monitoring device as claimed in claim 10, wherein the digital processing unit (112) is positioned remotely from the control unit (110), so as to form a central computer in a system for monitoring wear of a plurality of tires of the vehicle, and a link between the correlator (111) and the computer is provided by one of radio frequency (RF) and UWB signals.

12. The wear monitoring device as claimed in claim 5,

wherein a pulse amplifier (130) is arranged between an output of the pulse signal generator (120) and the one or more antennas, and

wherein a filter assembly (160), coupled to a low-noise amplifier (170), is fitted between the one or more antennas and an input of the pulse signal receiver (180).

13. The wear monitoring device as claimed in claim 5, wherein the control unit (110) comprises a correlator (111) that correlates successive digital UWB pulse signals (Sn) supplied by an analog-digital converter/sampler (ADCS) (182) and forms successive wear signatures, said correlator (111) being coupled to a digital processing unit (112) to determine a state of wear of the tire on the basis of the successive wear signatures.

14. The wear monitoring device as claimed in claim 13, wherein the digital processing unit (112) is positioned remotely from the control unit (110), so as to form a central computer in a system for monitoring wear of a plurality of tires of the vehicle, and a link between the correlator (111) and the computer is provided by one of radio frequency (RF) and UWB signals.

15. An on-board monitoring system for monitoring the wear of tires of vehicle wheels, comprising a plurality of wear monitoring devices as claimed in claim 5, and a central digital computer (300) incorporating a processing unit (112), each of said wear monitoring devices (100′

) configured to be incorporated into a wheel unit (200) fitted on each wheel of the vehicle, the control unit of each of said wear monitoring devices incorporating a correlator (111), a signal antenna (205, 210) fitted at an output of each wheel unit (200) transmits correlated UWB pulse signals receivable by the central digital computer (300) on board the vehicle, and said central digital computer (300) is connected to a signal reception antenna (310, 320) for receiving successive correlations transmitted by the antennas of the wheel units (200), and the processing unit (112) configured to determine a state of wear of each tire based on said received successive correlations.

16. The on-board wear monitoring system as claimed in claim 15, wherein the signal antenna (210) of each wheel unit is the one or more antennas of the wheel unit.

17. The on-board wear monitoring system as claimed in claim 15, wherein the wheel units (200) are each equipped with a pressure sensor, and the central digital computer (300) forms part of a tire pressure monitoring system.

18. A tire wear monitoring device, comprising:

a control unit (110) for signal control and data processing;

an ultra wide band (UWB) pulse signal generator (120) configured to generate UWB signals (Se), said UWB pulse signal generator (120) coupled to the control unit (110);

a UWB pulse signal receiver (180) coupled to said control unit (110); and

one or more antennas configured to receive reflected UWB pulses (150) reflected from at least one interface of the tire tread (11a, 12, 13, 14a, 14b) and from the road (2), the one or more antennas coupled to the UWB pulse signal receiver (180) and the generator (120),

wherein;

the UWB pulse signal generator (120) comprises a digital-analog converter (DAC) (121) that converts an initial signal (s1) launched by the control unit (110) and modulated via a baseband transmission clock (122), said converter (121) being coupled to a mixer (124) via a filter (123) so that a modulated and filtered signal (Sa) carries a brief pulse of a radio frequency (RF) signal supplied by an RF oscillator (125), also under control of the control unit (110), a duration of the initial signal being adjusted so that a carried signal corresponds to a frequency spectrum with a width of at least 25% of the central frequency value of said frequency spectrum, before being amplified (130) and then transmitted by the transmission antenna (140) in the form of a UWB pulse signal; and

the UWB pulse signal receiver (180) comprises a mixer (181) coupled to an analog-digital converter/sampler (ADCS) (182), said ADCS being coupled to the control unit (110) and configured to perform sampling upon a reflected UWB pulse signal received from the one or more antennas and mixed, after filtering (160) and amplification (170), with an RF signal supplied by a local radio frequency oscillator (184) which is also under control of the control unit (110), the sampling being timed by a baseband clock (183) under control of the control unit (110), to supply a digital UWB pulse signal (Sn) to the control unit (110) corresponding to the reflected UWB pulse signal (Sr).