US 7,599,774 B2Granted

Method and system for adaptively compensating closed-loop front-wheel steering control

AssigneeGM Global Technology Operations LLC

InventorsKwang-Keun Shin, Shih-Ken Chen

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Abstract

An active front-wheel vehicle steering control system that employs closed-loop control includes an adaptive compensation sub-system that compensates for changes in vehicle dynamic parameters. The control system includes a dynamic parameter estimation sub-system that provides an estimated front cornering compliance and rear cornering compliance based on a steering wheel angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal. The closed-loop control includes active gain for each of vehicle yaw rate, yaw acceleration, side-slip and side-slip rate, all based on the vehicle speed and vehicle dynamic parameter changes for use in generating a steering angle control signal to the front wheels of the vehicle.

Claims8

Dependent claims

An active front wheel steering control system for a vehicle having steerable front wheels and fixed rear wheels, comprising:

a vehicle steering wheel configured to generate a steering wheel angle signal corresponding to a steering wheel angle;
a steering actuator configured to control the steerable front wheels based upon a steering control signal comprising a combination of an open-loop steering control signal and a closed-loop steering control signal;
a real-time vehicle dynamics estimation subsystem configured to estimate vehicle dynamics parameters based upon signal inputs from vehicle sensors;
an open-loop control subsystem configured to provide the open-loop steering control signal corresponding to the steering wheel angle signal;
a closed-loop control subsystem configured to provide the closed-loop steering control signal based upon the estimated vehicle dynamics parameters;
a yaw rate feedback look-up table configured to provide an original yaw rate feedback angle signal;
and
a yaw rate feedback adaptive compensation sub-system configured to provide a corrected yaw rate feedback angle signal based on the estimated vehicle dynamics parameters;
wherein the yaw rate feedback adaptive compensation sub-system is configured to provide the corrected yaw rate feedback angle signal in accordance with the relationship:
δ
RP
=
K
RP
o
⁡
(
V
x
)
·
(
Ω
c
-
Ω
)
+
(
Δ
⁢
⁢
K
RP
Δ
⁢
⁢
T
⁢

o
⁢
⁢
Δ
⁢
⁢
T
⁡
(
V
x
)
+
Δ
⁢
⁢
K
RP
Δ
⁢
⁢
D
F

o
⁢
⁢
Δ
⁢
⁢
D
F
+
Δ
⁢
⁢
K
RP
Δ
⁢
⁢
D
R

o
⁢
⁢
Δ
⁢
⁢
D
R
)
·
(
Ω
c
-
Ω
)
where,
Ω is the yaw rate;
Ωc is the yaw rate command;
K0RP (Vx) is the nominal yaw rate feedback gain table as a function of vehicle speed;
ΔDF is the change in the front cornering compliance;
ΔDR is the change in the rear cornering compliance;
ΔT is the deviation in the open-loop gain;
and
Δ
⁢
⁢
K
RP
Δ
⁢
⁢
T
⁢

o
,
Δ
⁢
⁢
K
RP
Δ
⁢
⁢
D
F

o
;
Δ
⁢
⁢
K
RP
Δ
⁢
⁢
D
R

o
is the yaw rate P-gain sensitivity to open-loop gain, front cornering compliance, and rear cornering compliance, respectively.

144 more elements

An active front wheel steering control system for a vehicle having steerable front wheels and fixed rear wheels, comprising:

a vehicle steering wheel configured to generate a steering wheel angle signal corresponding to a steering wheel angle;
a steering actuator configured to control the steerable front wheels based upon a steering control signal comprising a combination of an open-loop steering control signal and a closed-loop steering control signal;
a real-time vehicle dynamics estimation subsystem configured to estimate vehicle dynamics parameters based upon signal inputs from vehicle sensors;
an open-loop control subsystem configured to provide the open-loop steering control signal corresponding to the steering wheel angle signal;
a closed-loop control subsystem configured to provide the closed-loop steering control signal based upon the estimated vehicle dynamics parameters;
a yaw acceleration feedback look-up table configured to provide an original yaw acceleration feedback angle signal;
a yaw acceleration feedback adaptive compensation sub-system configured to provide a corrected yaw acceleration feedback angle signal based on the estimated vehicle dynamics parameters;
wherein the yaw acceleration feedback adaptive compensation sub-system is configured to provide the corrected yaw acceleration feedback angle in accordance with the relationship:
δ
RD
=
K
RD
o
⁡
(
V
x
)
·
(
Ω
.
c
-
Ω
.
)
+
(
Δ
⁢
⁢
K
RD
Δ
⁢
⁢
T
⁢

o
⁢
⁢
Δ
⁢
⁢
T
⁡
(
V
x
)
+
Δ
⁢
⁢
K
RD
Δ
⁢
⁢
D
F

o
⁢
⁢
Δ
⁢
⁢
D
F
+
Δ
⁢
⁢
K
RD
Δ
⁢
⁢
D
R

o
⁢
⁢
Δ
⁢
⁢
D
R
)
·
(
Ω
.
c
-
Ω
.
)
where,
Ω is the yaw rate;
Ωc is the yaw rate command;
ΔDF is the change in the front cornering compliance;
ΔDR is the change in the rear cornering compliance;
ΔT is the deviation in the open-loop gain;
K0RD(Vx) is the nominal yaw acceleration feedback gain table as a function of the vehicle speed;
and
Δ
⁢
⁢
K
RD
Δ
⁢
⁢
T
⁢

o
,
Δ
⁢
⁢
K
RD
Δ
⁢
⁢
D
F

o
;
Δ
⁢
⁢
K
RD
Δ
⁢
⁢
D
R

o
is the yaw acceleration D-gain sensitivity to open-loop gain, front cornering compliance, and rear cornering compliance, respectively.

147 more elements

An active front wheel steering control system for a vehicle having steerable front wheels and fixed rear wheels, comprising:

a vehicle steering wheel configured to generate a steering wheel angle signal corresponding to a steering wheel angle;
a steering actuator configured to control the steerable front wheels based upon a steering control signal comprising a combination of an open-loop steering control signal and a closed-loop steering control signal;
a real-time vehicle dynamics estimation subsystem configured to estimate vehicle dynamics parameters based upon signal inputs from vehicle sensors;
an open-loop control subsystem configured to provide the open-loop steering control signal corresponding to the steering wheel angle signal;
a closed-loop control subsystem configured to provide the closed-loop steering control signal based upon the estimated vehicle dynamics parameters;
a side-slip feedback look-up table configured to provide an original side-slip feedback angle signal;
a side-slip feedback adaptive compensation sub-system configured to provide a corrected side-slip feedback angle signal based on the estimated vehicle dynamics parameters;
wherein the side-slip feedback adaptive compensation sub-system is configured to provide the corrected side-slip feedback angle signal in accordance with the relationship:
δ
SP
=
K
SP
o
⁡
(
V
x
)
·
V
y
+
(
Δ
⁢
⁢
K
SP
Δ
⁢
⁢
T
⁢

o
⁢
⁢
Δ
⁢
⁢
T
⁡
(
V
x
)
+
Δ
⁢
⁢
K
SP
Δ
⁢
⁢
D
F

o
⁢
⁢
Δ
⁢
⁢
D
F
+
Δ
⁢
⁢
K
SP
Δ
⁢
⁢
D
R

o
⁢
⁢
Δ
⁢
⁢
D
R
)
·
V
y
where
Ω is the yaw rate;
Ωc is the yaw rate command;
ΔDF is the change in the front cornering compliance;
ΔDR is the change in the rear cornering compliance;
ΔT is the deviation in the open-loop gain;
K0SP(Vx) is the nominal side-slip feedback gain table as a function of the vehicle speed;
and
Δ
⁢
⁢
K
SP
Δ
⁢
⁢
T
⁢

o
,
Δ
⁢
⁢
K
SP
Δ
⁢
⁢
D
F

o
;
Δ
⁢
⁢
K
SP
Δ
⁢
⁢
D
R

o
is the side-slip gain sensitivity to open-loop gain, front cornering compliance, and rear cornering compliance, respectively.

135 more elements

An active front wheel steering control system for a vehicle having steerable front wheels and fixed rear wheels, comprising:

a vehicle steering wheel configured to generate a steering wheel angle signal corresponding to a steering wheel angle;
a steering actuator configured to control the steerable front wheels based upon a steering control signal comprising a combination of an open-loop steering control signal and a closed-loop steering control signal;
a real-time vehicle dynamics estimation subsystem configured to estimate vehicle dynamics parameters based upon signal inputs from vehicle sensors;
an open-loop control subsystem configured to provide the open-loop steering control signal corresponding to the steering wheel angle signal;
a closed-loop control subsystem configured to provide the closed-loop steering control signal based upon the estimated vehicle dynamics parameters;
a side-slip rate feedback look-up table configured to provide an original side-slip rate feedback angle signal;
a side-slip rate feedback adaptive compensation sub-system configured to provide a corrected side-slip rate feedback angle signal based on the estimated vehicle dynamics parameters;
wherein the side-slip rate feedback adaptive compensation sub-system is configured to provide the corrected side-slip rate feedback angle in accordance with the relationship:
δ
SD
=
K
SD
o
⁡
(
V
x
)
·
V
.
y
+
(
Δ
⁢
⁢
K
SD
Δ
⁢
⁢
T
⁢

o
⁢
⁢
Δ
⁢
⁢
T
⁡
(
V
x
)
+
Δ
⁢
⁢
K
SD
Δ
⁢
⁢
D
F

o
⁢
⁢
Δ
⁢
⁢
D
F
+
Δ
⁢
⁢
K
SD
Δ
⁢
⁢
D
R

o
⁢
⁢
Δ
⁢
⁢
D
R
)
·
V
.
y
where
Ω is the yaw rate;
Ωc is the yaw rate command;
ΔDF is the change in the front cornering compliance;
ΔDR is the change in the rear cornering compliance;
ΔT is the deviation in the open-loop gain;
K0SD(Vx) is the nominal side-slip rate feedback gain table as a function of the vehicle speed;
and
Δ
⁢
⁢
K
SD
Δ
⁢
⁢
T
⁢

o
,
Δ
⁢
⁢
K
SD
Δ
⁢
⁢
D
F

o
;
Δ
⁢
⁢
K
SD
Δ
⁢
⁢
D
R

o
is the side-slip rate gain sensitivity to open-loop gain, front cornering compliance, and rear cornering compliance, respectively.

137 more elements

Dependencies are inferred from the claim text.