Road curvature estimation for rearview mirror adjustment system
View Patent ↗A system and method for automatically correcting the viewing angle of a rear-view mirror on a vehicle when the vehicle is traveling around a curve. The system estimates the curvature of the road using only vehicle speed and vehicle steering angle information. The road curvature estimation is used to determine the radius of curvature of the road, which can then be used to determine the corrected viewing angle of the rear-view mirror. Depending on whether the road is curving to the right or to the left will determine whether the left side rear-view mirror or the right side rear-view mirror will be adjusted.
1. A method for correcting a viewing angle of a rear-view mirror on a vehicle when the vehicle is traveling around a curve, said method comprising:
determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle;
calculating a corrected mirror viewing angle based on the curvature of the road; and
changing the viewing angle of the rear-view mirror using the corrected viewing angle.
2. The method according to claim 1 wherein determining the curvature of the road includes using the equation:
ρ
=
1
L
1
+
K
us
v
2
Lg
(
δ
f
-
δ
r
)
where ρ is the curvature of the road, L is the wheel base of the vehicle, K us a coefficient, v is the vehicle speed, g is acceleration due to gravity, δ F is the front wheel steering angle and δ R is the rear steering angle of the vehicle.
3. The method according to claim 1 wherein calculating a corrected mirror viewing angle includes calculating the angle using the curvature of the road and the radius of the curve.
4. The method according to claim 3 wherein the corrected viewing angle is calculated by the equation:
Δ
α
=
α
-
α
o
=
e
e
ρ
(
2
-
e
ρ
)
(
ρ
-
ρ
o
)
where Δα is the corrected mirror angle, e is the distance between an edge of the curve and a side line of the vehicle, α is the angle between the center of the lane and the corrected viewing line, α 0 is the angle between the side line and an original viewing angle line of the rear-view mirror and ρ is the curvature.
5. The method according to claim 1 wherein only the rear-view mirror that is on the side of the vehicle towards the direction that the road is curving will be corrected.
6. The method according to claim 1 wherein determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle includes determining the speed of the vehicle and the steering angle of the vehicle using vehicle sensors.
7. The method according to claim 1 wherein determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle includes determining the steering angle of both front wheels and rear wheels of the vehicle.
8. A method for correcting a viewing angle of a rear-view mirror on a vehicle when the vehicle is traveling around a curve, said method comprising:
determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle by the equation:
ρ
=
1
L
1
+
K
us
v
2
Lg
(
δ
f
-
δ
r
)
where ρ is the curvature of the road, L is the wheel base of the vehicle, K us is a coefficient, v is the vehicle speed, g is acceleration due to gravity, δ F is the front wheel steering angle and δ R is the rear steering angle of the vehicle;
calculating a corrected mirror viewing angle based on the curvature of the road including calculating the angle using the curvature of the road and the radius of the curve;
determining whether a left side rear-view mirror or a right side rear-mirror should be changed; and
changing the viewing angle of the mirror using the corrected viewing angle.
9. The method according to claim 8 wherein the corrected viewing angle is calculated by the equation:
Δ
α
=
α
-
α
o
=
e
e
ρ
(
2
-
e
ρ
)
(
ρ
-
ρ
o
)
where Δα is the corrected mirror angle, e is the distance between an edge of the curve and a side line of the vehicle, α is the angle between the center of the lane and the corrected viewing line, α 0 is the angle between the side line and an original viewing angle line of the rear-view mirror and ρ is the curvature.
10. The method according to claim 8 wherein only the rear-view mirror that is on the side of the vehicle towards the direction that the road is curving will be corrected.
11. The method according to claim 8 wherein determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle includes determining the speed of the vehicle and the steering angle of the vehicle using vehicle sensors.
12. The method according to claim 8 wherein determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle includes determining the steering angle of both front wheels and rear wheels of the vehicle.
13. A system for correcting a viewing angle of a rear-view mirror on a vehicle when the vehicle is traveling around a curve, said system comprising:
means for determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle;
means for calculating a corrected mirror viewing angle based on the curvature of the road; and
means for changing the viewing angle of the mirror using the corrected viewing angle.
14. The system according to claim 13 wherein the means for determining the curvature of the road includes using the equation:
ρ
=
1
L
1
+
K
us
v
2
Lg
(
δ
f
-
δ
r
)
where ρ is the curvature of the road, L is the wheel base of the vehicle, K us is a coefficient, v is the vehicle speed, g is acceleration due to gravity, δ F is the front wheel steering angle and δ R is the rear steering angle of the vehicle.
15. The system according to claim 13 wherein the means for calculating a corrected mirror viewing angle calculates the angle using the curvature of the road and the radius of the curve.
16. The system according to claim 13 wherein the means changing the viewing angle corrects the viewing angle uses the equation:
Δα
=
α
-
α
o
=
e
e
ρ
(
2
-
e
ρ
)
(
ρ
-
ρ
o
)
where Δα is the corrected mirror angle, e is the distance between an edge of the curve and a side line of the vehicle, α is the angle between the center of the lane and the corrected viewing line, α 0 is the angle between the side line and an original viewing angle line of the rear-view mirror and ρ is the curvature.
17. The system according to claim 13 wherein only the rear-view mirror that is on the side of the vehicle towards the direction that the road is curving will be corrected.
18. The system according to claim 17 wherein the means for determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle determines the speed of the vehicle and the steering angle of the vehicle using vehicle sensors.
19. The system according to claim 13 wherein the means for determining the curvature of the road using only a speed of the vehicle and a steering angle of the vehicle determines the steering angle of both front wheels and rear wheels of the vehicle.