Control system of drive wheel of vehicle and control method of drive wheel of vehicle using the same
View Patent ↗A control system of a wheel of a vehicle includes: a wheel speed sensor configured to measure a wheel speed of wheels of the vehicle; a data storage configured to store data relating to a plurality of abnormal patterns based on a slip state or a lock state of each wheel; and a controller configured to extract wheel speed pattern data using wheel speeds measured from the wheel speed sensor, to compare the extracted wheel speed pattern data with the stored data relating to the plurality of abnormal patterns, to determine an abnormal pattern among the plurality of abnormal patterns most similar to the extracted wheel speed pattern data according to the comparison, and to detect an abnormal wheel among the wheels of the vehicle based on the determined abnormal pattern.
1. A control system of a wheel of a vehicle, comprising:
a wheel speed sensor configured to measure a wheel speed of wheels of the vehicle;
a data storage configured to store data relating to a plurality of abnormal patterns based on a slip state or a lock state of each wheel; and
a controller configured to extract wheel speed pattern data using wheel speeds measured from the wheel speed sensor, to compare the extracted wheel speed pattern data with the stored data relating to the plurality of abnormal patterns, to determine an abnormal pattern among the plurality of abnormal patterns most similar to the extracted wheel speed pattern data according to the comparison, and to detect an abnormal wheel among the wheels of the vehicle based on the determined abnormal pattern,
wherein the controller is further configured to extract a plurality of correlation data based on the comparison of the extracted wheel speed pattern data with the stored data relating to the plurality of abnormal patterns, to determine the abnormal pattern based on the extracted plurality of correlation data, and to detect the abnormal wheel based on the determined abnormal pattern and vehicle operation state information, and
wherein the plurality of correlation data is obtained by dividing a covariance result between the wheel speed pattern data and the abnormal pattern data with a product of standard deviation of the wheel speed pattern data and standard deviation of the abnormal pattern data.
2. The control system according to claim 1 , wherein the determined abnormal pattern has a largest correlation data value among the plurality of correlation data.
3. The control system according to claim 1 , wherein the vehicle operation state information indicates whether the vehicle is accelerating or braking.
4. The control system according to claim 1 , wherein the controller is further configured to calculate an average wheel speed of the wheels except for the detected abnormal wheel and to control steering of a rear wheel of the vehicle based on the calculated average wheel speed of the wheels except for the detected abnormal wheel.
5. The control system according to claim 1 , wherein the controller is further configured to control an actuator positioned between the wheels of the vehicle and to control steering of a wheel among the wheels of the vehicle.
6. The control system according to claim 1 , wherein the controller is further configured to determine whether to steer a rear wheel of the vehicle in the same direction as a front wheel of the vehicle or in an opposite direction of the front wheel based on an average wheel speed and a predetermined speed stored in the data storage.
7. The control system according to claim 6 , wherein the controller is further configured to steer the rear wheel in the opposite direction of the front wheel when the average wheel speed is less than or equal to the predetermined speed.
8. The control system according to claim 6 , wherein the controller is further configured to steer the rear wheel in the same direction as the front wheel when the average wheel speed is greater than the predetermined speed.
9. The control system according to claim 1 , wherein the wheel speed pattern data comprises front and rear wheel pattern data indicating a speed difference between corresponding front and rear wheels among the wheels of the vehicle, diagonal wheel pattern data indicating a speed difference between diagonally corresponding wheels, right and left drive wheel pattern data indicating a speed difference between corresponding right and left wheels, and region pattern data.
10. The control system according to claim 9 , wherein the wheels of the vehicle comprise a left front wheel, a left rear wheel, a right front wheel, and a right rear wheel.
11. The control system according to claim 9 , wherein the front and rear wheel pattern data is derived according to Expression 1 below:
(
FL
+
FR
)
-
(
RL
+
RR
)
Vave
,
wherein FL is a left front wheel speed, FR is a right front wheel speed, RL is a left rear wheel speed, RR is a right rear wheel speed, and Vave is an average wheel speed.
12. The control system according to claim 9 , wherein the diagonal wheel pattern data is derived according to Expression 2 below:
(
FL
+
RR
)
-
(
FR
+
RL
)
Vave
,
wherein FL is a left front wheel speed, FR is a right front wheel speed, RL is a left rear wheel speed, RR is a right rear wheel speed, and Vave is an average wheel speed.
13. The control system according to claim 9 , wherein the right and left wheel pattern data is derived according to Expression 3 below:
(
FL
+
RL
)
-
(
FR
+
RR
)
Vave
,
wherein FL is a left front wheel speed, FR is a right front wheel speed, RL is a left rear wheel speed, RR is a right rear wheel speed, and Vave is an average wheel speed.
14. The control system according to claim 9 , wherein the region pattern data is derived according to Expression 4 below:
max(A,B,C)×sign(A,B,C),
wherein A is the front and rear wheel pattern data, B is the diagonal wheel pattern data, and C is the right and left wheel pattern data.
15. The control system according to claim 1 , wherein:
the plurality of correlation data is derived according to Expression 5 below:
P
x
,
y
=
Cov
(
x
,
y
)
σ
x
σ
y
,
wherein P is a correlation coefficient, x is the wheel speed pattern data, y is the abnormal pattern data, σ x is the standard deviation of wheel speed pattern data, and σ y is the standard deviation of abnormal pattern data, and
the plurality of correlation data is further derived according to Expression 6 below:
Cov
(
x
,
y
)
=
∑
i
=
1
N
(
x
i
-
u
x
)
(
y
i
-
u
y
)
N
-
1
,
wherein x is the wheel speed pattern data, y is the abnormal pattern data, u x is average of wheel speed pattern data, and u y is average of abnormal pattern data.
16. A control method of a wheel of a vehicle, the method comprising:
measuring a wheel speed of wheels of the vehicle using a wheel speed sensor;
extracting wheel speed pattern data using wheel speeds measured from the wheel speed sensor;
comparing the extracted wheel speed pattern data with data relating to a plurality of abnormal patterns stored in a data storage;
extracting a plurality of correlation data based on the comparison of the extracted wheel speed pattern data with the stored data relating to the plurality of abnormal patterns;
determining the abnormal pattern based on the extracted plurality of correlation data; and
detecting the abnormal wheel based on the determined abnormal pattern and vehicle operation state information,
wherein the plurality of correlation data is obtained by dividing a covariance result between the wheel speed pattern data and the abnormal pattern data with a product of standard deviation of the wheel speed pattern data and standard deviation of the abnormal pattern data.
17. The method according to claim 16 , further comprising:
calculating a difference between measured wheel speeds measured from the wheel speed sensor;
comparing the difference between the wheel speeds with a predetermined speed value;
calculating an average wheel speed when the difference between the measured wheel speeds is less than the predetermined speed value; and
extracting wheel speed pattern data when the difference between the measured wheel speeds is greater than the predetermined speed value.
18. The method according to claim 16 , further comprising,
calculating an average wheel speed of the wheels except for the detected abnormal wheel; and
controlling steering of a rear wheel of the vehicle based on the calculated average wheel speed of the wheels except for the detected abnormal wheel.