Lane-change assistance system of vehicle and lane-change assistance method thereof
View Patent ↗Disclosed herein are a lane-change assistance system of a vehicle and a lane-change assistance method thereof. The lane change assistance system includes a wheel speed sensor to detect a wheel speed of the vehicle, a steering angle sensor to detect a steering angle of the vehicle, and a micro controller unit to calculate, using the wheel speed and the steering angle, a desired yaw rate value required to allow the vehicle to return to an original lane when attempting to move the vehicle to an adjacent lane, but another vehicle in the adjacent lane threatens the corresponding vehicle, to compare the desired yaw rate value with a preset threshold value, and to assist a lane change maneuver of the vehicle based on the comparison result.
1. A lane change assistance system of a vehicle, comprising:
a wheel speed sensor to detect a wheel speed of the vehicle;
a steering angle sensor to detect a steering angle of the vehicle; and
a micro controller unit to calculate, using the wheel speed and the steering angle, a desired yaw rate value required to allow the vehicle to return to an original lane when attempting to move the vehicle to an adjacent lane, but another vehicle in the adjacent lane threatens the corresponding vehicle, to compare the desired yaw rate value with a preset threshold value, and to assist a lane change manoeuvre of the vehicle based on the comparison result.
2. The system according to claim 1 , wherein the micro controller unit calculates the desired yaw rate value using Equation 1 and Equation 2 represented as follows:
{dot over (ψ)} dos =Yaw_Rate —Original +Yaw_Rate —Target Equation 1
here, Yaw_Rate —Target is a value determined by a driving situation, and has a value in a range of about −5 deg/s to about 5 deg/s, and
Yaw_Rate
_
Original
=
V
l
f
+
l
r
+
m
V
2
(
l
r
C
ar
-
l
f
C
af
)
2
C
af
C
ar
L
δ
.
Equation
2
3. The system according to claim 2 , wherein the micro controller unit performs heading-angle control if the desired yaw rate value is less than the preset threshold value, and performs haptic control if the desired yaw rate value is equal to or greater than the preset threshold value, thereby assisting the lane change manoeuvre of the vehicle.
4. The system according to claim 3 , wherein the micro controller unit calculates a heading-angle using Equation 3 represented as follows and calculates a target moment value using Equation 4 represented as follows:
ψ
des
=
∫
(
Yaw_Rate
_
Measured
-
Yaw_Rate
_
Original
)
ⅆ
t
,
and
Equation
3
M
z
=
(
-
a
·
γ
-
b
·
a
y
-
c
·
δ
f
+
γ
.
d
-
K
·
Sat
(
γ
-
γ
d
ɛ
)
)
·
I
z
where
a
=
-
2
C
f
C
r
l
f
+
l
r
(
C
f
+
C
r
)
2
I
z
V
x
b
=
m
(
l
f
C
f
-
l
r
C
r
)
(
C
f
+
C
r
)
I
z
c
=
2
C
f
C
r
C
f
+
C
r
l
f
+
l
r
I
z
.
Equation
4
5. The system according to claim 4 , wherein the micro controller unit performs the heading-angle control by transmitting the calculated heading-angle and the target moment value to a brake system.
6. The system according to claim 3 , wherein the micro controller unit calculates a target moment value using Equation 5 represented as follows:
M
z
=
(
-
a
·
γ
-
b
·
a
y
-
c
·
δ
f
+
γ
.
d
-
K
·
Sat
(
γ
-
γ
d
ɛ
)
)
·
I
z
where
a
=
-
2
C
f
C
r
l
f
+
l
r
(
C
f
+
C
r
)
2
I
z
V
x
b
=
m
(
l
f
C
f
-
l
r
C
r
)
(
C
f
+
C
r
)
I
z
c
=
2
C
f
C
r
C
f
+
C
r
l
f
+
l
r
I
z
.
Equation
5
7. The system according to claim 6 , wherein the micro controller unit performs the haptic control by transmitting the calculated target moment value to a brake system.
8. A lane change assistance method of a vehicle including a wheel speed sensor to detect a wheel speed of the vehicle and a steering angle sensor to detect a steering angle of the vehicle, the method comprising:
calculating, using the wheel speed and the steering angle, a desired yaw rate value required to allow the vehicle to return to an original lane when attempting to move the vehicle to an adjacent lane, but another vehicle in the adjacent lane threatens the corresponding vehicle;
comparing the desired yaw rate value with a preset threshold value; and
assisting a lane change manoeuvre of the vehicle based on the comparison result.
9. The method according to claim 8 , wherein the calculation of the desired yaw rate value is performed using Equation 1 and Equation 2 represented as follows:
{dot over (ψ)} dos =Yaw_Rate —Original +Yaw_Rate —Target Equation 1
here, Yaw_Rate —Target is a value determined by a driving situation, and has a value in a range of about −5 deg/s to about 5 deg/s, and
Yaw_Rate
_
Original
=
V
l
f
+
l
r
+
m
V
2
(
l
r
C
ar
-
l
f
C
af
)
2
C
af
C
ar
L
δ
.
Equation
2
10. The method according to claim 9 , wherein the assistance of the lane change manoeuvre of the vehicle includes performing heading-angle control if the desired yaw rate value is less than the preset threshold value, and performing haptic control if the desired yaw rate value is equal to or greater than the preset threshold value.
11. The method according to claim 10 , further comprising calculating a heading-angle using Equation 3 represented as follows and calculating a target moment value using Equation 4 represented as follows:
ψ
des
=
∫
(
Yaw_Rate
_
Measured
-
Yaw_Rate
_
Original
)
ⅆ
t
,
and
Equation
3
M
z
=
(
-
a
·
γ
-
b
·
a
y
-
c
·
δ
f
+
γ
.
d
-
K
·
Sat
(
γ
-
γ
d
ɛ
)
)
·
I
z
where
a
=
-
2
C
f
C
r
l
f
+
l
r
(
C
f
+
C
r
)
2
I
z
V
x
b
=
m
(
l
f
C
f
-
l
r
C
r
)
(
C
f
+
C
r
)
I
z
c
=
2
C
f
C
r
C
f
+
C
r
l
f
+
l
r
I
z
.
Equation
4
12. The method according to claim 11 , further comprising transmitting the calculated heading-angle and the target moment value to a brake system to enable implementation of the heading-angle control.
13. The method according to claim 10 , further comprising calculating a target moment value using Equation 5 represented as follows:
M
z
=
(
-
a
·
γ
-
b
·
a
y
-
c
·
δ
f
+
γ
.
d
-
K
·
Sat
(
γ
-
γ
-
d
ɛ
)
)
·
I
z
where
a
=
-
2
C
f
C
r
l
f
+
l
r
(
C
f
+
C
r
)
2
I
z
V
x
b
=
m
(
l
f
C
f
-
l
r
C
r
)
(
C
f
+
C
r
)
I
z
c
=
2
C
f
C
r
C
f
+
C
r
l
f
+
l
r
I
z
.
Equation
5
14. The method according to claim 13 , further comprising transmitting the calculated target moment value to a brake system to enable implementation of the haptic control.