PRE-ALERT OF LCC's STEERING TORQUE LIMIT EXCEED

Patent metadata

Field	Value
Publication number	US-2016288831-A1
Application number	US-201315038173-A
Country	US
Kind code	A1
Filing date	Dec 6, 2013
Priority date	Dec 6, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

A method for providing a warning to a vehicle driver when a lane keeping and/or lane centering system will be unable to negotiate a tight curve at the present vehicle speed prior to the vehicle reaching the curve. The method obtains lane information at a predetermined number of sample times in the future and generates a desired path for the vehicle. The method also obtains vehicle motion information and determines steering angles for the vehicle for the vehicle to track the desired path based on the desired path and vehicle motion. The method determines the steering torque for each of the steering angles and determines whether any of the steering torques exceed the predetermine torque limit. The method issues an alert if any of the steering torques do exceed the predetermined torque limit prior to the lane keeping system being required to provide that torque to steer the vehicle.

First claim

What is claimed is:

1 . A method for determining whether a vehicle steering torque exceeds a predetermined maximum steering torque limit in advance while a vehicle is being controlled by a lane keeping system, said method comprising:
obtaining lane information concerning a lane that the vehicle is traveling in at a predetermined number of sample times in the future; generating a desired path for the vehicle to maintain the vehicle in the lane; obtaining vehicle motion information required to maintain the vehicle on the desired path at each of the sample times; determining steering angles for the vehicle that are necessary for the vehicle to track the desired path at each of the sample times based on the desired path and the vehicle motion information; determining the vehicle steering torque required to steer the vehicle for each of the steering angles; determining whether any of the steering torques exceeds the predetermine maximum torque limit; and issuing an alert if any of the steering torques does exceed the predetermined maximum torque limit prior to the lane keeping system being required to command that torque to steer the vehicle.

2 . The method according to claim 1 wherein generating a desired path includes using a polynomial equation.

3 . The method according to claim 2 wherein the polynomial equation is:

y
n



(

x
n

)

=

a
0

+

a
1



x
n

+

a
2



x
n
2

+

a
3



x
n
3

+

a
4



x
n
4

+

a
5



x
n
5

0
≤

x
n

=

x

v
x


Δ



T

≤
1

y
n

=

y
L

where x is the longitudinal distance from the vehicle center, y is the lateral distance from the vehicle center, v x is the vehicle longitudinal speed, L is the lane width, ΔT is the time of the path generation distance, and a are coefficients.

4 . The method according to claim 1 wherein obtaining vehicle motion information includes obtaining vehicle longitudinal speed v, vehicle lateral speed v y , vehicle yaw rate w, vehicle lateral acceleration a y and vehicle yaw acceleration {dot over (w)}.

5 . The method according to claim 4 wherein obtaining vehicle motion information can be directly determined from desired path parameters and using the equations:
v y ={dot over (y)}−v x φ

{dot over (y)}≡dy/dt=y′v x
y′= 5 a 5 x 4 +4 a 4 x 3 +3 a 3 x 2 +2 a 2 x+a 1
a y ≡ÿ=d 2 y/dt 2 =y″v x 2 +y′a x
y″= 20 a 5 x 3 +12 a 4 x 2 +6 a 3 x+ 2 a 2
w=y′

{dot over (w)}=d ( y ′)/ dt=y″v x .

6 . The method according to claim 1 wherein determining steering angles for the vehicle includes using the equation:

[

v
.

y

w
.

]

=

[

-

C
f

+

C
r

mv
x

bC
r

-

aC
f

mv
x

Assignees

• Gm Global Tech Operations Llc

Inventors

• Lee Jin-Woo

Classifications

• B60W30/10

  Path keeping {(cruise control for automatically following a preceding vehicle B60W30/165)} · CPC title

• B62D15/029

  Steering assistants using warnings or proposing actions to the driver without influencing the steering system · CPC title

• B62D15/025 Primary

  Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence) · CPC title

• B60Y2400/90

  Driver alarms · CPC title

• B60Y2300/12

  Lane keeping · CPC title