Method of detecting an occurrence of hydroplaning of a tire on a road
View Patent ↗In a method of detecting an occurrence of hydroplaning of a tire of a vehicle travelling on wet ground, a tread of the tire of the vehicle is equipped with one or more sensors each capable of measuring a compression experienced locally by the tread when the tire is rolling on the ground and of producing a signal corresponding to these measurements. According to the method, measurements are obtained of a compression when the tire is rolling on the ground; a signal corresponding to these measurements is produced; a portion of the signal relating to a passing of one or more sensors into an apparent area of contact between the tire and the ground is extracted; an instantaneous value (ΔE, R z ), corresponding to a presence of an indirect contact region of the apparent area of contact between the tread and the ground, is determined from the extracted portion of the signal; and an alarm is triggered when the instantaneous value satisfies a given relationship.
1. A method of detecting an occurrence of hydroplaning of a tire of a vehicle travelling on wet ground, a tread of the tire being equipped with one or more sensors each capable of measuring a compression experienced locally by the tread when the tire is rolling on the ground and of producing a signal corresponding to measurements made by the one or more sensors, the method comprising:
obtaining measurements of a compression when a tire is rolling on the ground;
producing a signal corresponding to the measurements;
extracting a portion of the signal relating to a passing of one or more sensors into an apparent area of contact between a tread of the tire and the ground;
determining an instantaneous value (ΔE, R z ), corresponding to a presence of an indirect contact region of the apparent area of contact between the tread of the tire and the ground, based on the extracted portion of the signal, and;
triggering an alarm when the instantaneous value satisfies a given relationship, wherein the determining of an instantaneous value ΔE includes:
differentiating the signal,
determining a minimum value
(
d
σ
dx
)
min
and a maximum value
(
d
σ
dx
z
)
max
of the differentiated signal and also positions of the minimum value and the maximum value (l min , l max ), and
calculating the instantaneous value ΔE to be a difference in position between the minimum and maximum values of the differentiated signal: ΔE=l max −l min .
2. A method according to claim 1 , wherein the measurements of the compression are made by the one or more sensors, and the compression is characteristic of compressive forces experienced by the tread of the tire in a direction normal to a plane of the ground.
3. A method according to claim 1 , wherein the alarm is triggered when the instantaneous value ΔE exceeds a given threshold.
4. A method according to one of claims 2 and 3 , wherein the determining of an instantaneous value (R z ) is such that:
when the extracted portion of the signal includes two successive plateaus, the instantaneous value (R z ) is equal to:
R z =f (σ zi ,σ zd ),
in which σ zi represents an amplitude of compressive stresses of the first plateau and σ zd represents an amplitude of compressive stresses of the second plateau, and
when the extracted portion of the signal includes a single plateau, the instantaneous value (R z ) is equal to a constant C.
5. A method according to claim 4 ,
wherein:
R
z
=
f
(
σ
zi
,
σ
zd
)
=
σ
zi
-
σ
zd
σ
zd
,
wherein C is equal to −1.
6. A method according to claim 5 , wherein the alarm is triggered when the instantaneous value (R z ) is positive.
7. A method according to claim 4 ,
wherein:
R
z
=
f
(
σ
zi
,
σ
zd
)
=
σ
zi
σ
zd
,
wherein C is equal to 0.
8. A method according to claim 7 , wherein the alarm is triggered when the instantaneous value (R z ) is greater than 1.
9. A method according to claim 4 , wherein the alarm is triggered when the instantaneous value (R z ) is above a given value.
10. A method according to claim 4 , wherein, in the triggering of an alarm, first and second alarms are triggered in succession, the first alarm being triggered when a first instantaneous value (ΔE) exceeds a given threshold, and the second alarm of greater intensity being triggered when a second instantaneous value (R z ) exceeds a second given threshold.
11. A device for detecting an occurrence of hydroplaning of a tire of a vehicle travelling on wet ground, the tire including tread equipped with one or more sensors each configured to measure compressive stresses experienced locally by the tread rolling on the ground, and the tire including a transmitter for transmitting a signal corresponding to measurements of stresses sensed by the one or more sensors, the device comprising:
a signal processing unit that extracts, from the transmitted signal, a signal portion corresponding to a number or to a duration of passage of the one or more sensors in an area of contact of the tread of the tire rolling on the ground, wherein the signal processing unit is configured to execute a program for implementing a method of detecting an occurrence of hydroplaning based on the extracted signal, the method including:
obtaining measurements from the one or more sensors of a compression when the tire is rolling on the ground;
producing a signal corresponding to the measurements;
extracting a portion of the signal relating to a passing of the one or more sensors into an apparent area of contact between the tread of the tire and the ground;
determining an instantaneous value (ΔE, R z ), corresponding to a presence of an indirect contact region of the apparent area of contact between the tread of the tire and the ground, based on the extracted portion of the signal; and
triggering an alarm when the instantaneous value satisfies a given relationship,
wherein the determining of an instantaneous value ΔE includes:
differentiating the signal,
determining a minimum value
(
d
σ
dx
)
min
and a maximum value
(
d
σ
dx
z
)
max
of the differentiated signal and also positions of the minimum value and the maximum value (l min , l max ), and
calculating the instantaneous value ΔE to be a difference in position between the minimum and maximum values of the differentiated signal: ΔE=l max −l min .