Driver workload-based vehicle stability enhancement system

• US 7,996,130 B2
• Filed: 04/19/2010
• Issued: 08/09/2011
• Est. Priority Date: 04/13/2006
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Zhang, Jing, Zhang, Yilu, Chin, Yuen-Kwok, Lin, William C.
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Patton; Spencer
• Application Number:
  US12/762,739
• Publication Number:
  US 20100198452A1
• Time in Patent Office: 477 Days
• Field of Search: 701/39, 701/40, 701/42, 701/43, 701/70, 701/76, 701/77, 701/82, 701/90, 701/91, 701/92, 701/41, 303/140, 303/146, 340/438, 340/439, 340/441, 340/575, 340/576
• US Class Current: 701/42
• CPC Class Codes: B60T 2220/02 Driver type; Driving style; Driver adaptive features
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B60T 8/17552 responsive to the tire sideslip angle or the vehicle body slip angle

Abstract

A vehicle stability enhancement system that is adapted for an estimated driver workload. The system includes a driver workload estimation processor that estimates the driver workload based on certain factors, such as the vehicle speed or driver-behavior factors. The driver workload estimation is used to adjust the damping ratio and natural frequency in dynamic filters in a command interpreter to adjust a desired yaw rate signal and a desired side-slip signal. The driver workload estimation is also used to generate a yaw rate multiplication factor and a side-slip multiplication factor that modify a yaw rate stability signal and a side-slip stability signal in a feedback control processor that generates a stability control signal.

Claims

1. A vehicle stability enhancement system configured to provide vehicle stability control for a vehicle, said system comprising:

a driver workload estimator configured to provide a driver workload estimation signal indicative of the workload of a driver driving the vehicle, wherein the driver workload estimator sets the driver workload estimation signal to a first value if the vehicle speed is below 5 mph, sets the driver workload estimation signal to a second value if the vehicle speed is greater than or equal to 5 mph and less than 20 mph and sets the driver workload estimation signal to a third value if the vehicle speed is greater than or equal to 20 mph, where the first value indicates a low driver workload, the second value indicates an average driver workload and the third value indicates a high driver workload;

a command interpreter responsive to vehicle operation signals and the driver workload estimation signal, said command interpreter configured to generate a desired yaw rate signal and a desired side-slip signal, wherein said command interpreter includes a yaw rate command generator and a side-slip command generator, said yaw rate command generator including a first filter responsive to a steady-state yaw rate signal and using a damping ratio and a natural frequency to filter the steady-state yaw rate signal, said side-slip command generator including a second filter responsive to a steady-state side-slip signal and using the damping ratio and the natural frequency to filter the steady-state side-slip signal, said command interpreter further including a control command adaptation processor responsive to the driver workload estimation signal, where the control command adaptation processor changes the damping ratio and the natural frequency in the first and second filters depending on the driver workload estimation signal; and

a feedback control processor responsive to the driver workload estimation signal, the desired yaw rate signal, the desired side-slip signal, a measured yaw rate signal and a measured side-slip signal, said feedback control processor configured to generate a stability control signal to control the vehicle.

2. The system according to claim 1 wherein the feedback control processor generates a first error signal as the difference between the desired yaw rate signal and the measured yaw rate signal and a second error signal as the difference between the desired side-slip signal and the measured side-slip signal, said feedback control processor including a first look-up table that provides a yaw rate gain signal in response to the yaw rate error signal and a second look-up table that provides a side-slip gain signal in response to the side-slip error signal, said feedback control processor further including a first multiplier that multiplies the yaw rate error signal times the yaw rate gain signal to generate a yaw rate stability signal and a second multiplier that multiplies the side-slip error signal times the side-slip gain signal to generate a side-slip stability signal, said feedback control processor further including a control gain adaptation processor responsive to the driver workload estimation signal and generates a yaw rate multiplier factor and a side-slip multiplier factor, said feedback control processor further including a third multiplier that multiplies the yaw rate stability signal times the yaw rate multiplier factor to generate a modified yaw rate stability signal and a fourth multiplier that multiplies the side-slip stability signal times the side-slip multiplier factor to generate a modified side-slip stability signal, said feedback control processor further including an adder that adds the modified yaw rate stability signal and the modified side-slip stability signal to generate the stability control signal.

3. The system according to claim 2 wherein the feedback control processor determines whether the vehicle is in an understeer condition before it determines the yaw rate multiplier factor, and sets the yaw rate multiplier factor to 1 if the vehicle is in an understeer condition.

4. The system according to claim 1 wherein the vehicle operation signals include a vehicle speed signal and a hand-wheel angle signal.

5. A vehicle stability enhancement system configured to provide vehicle stability control for a vehicle, said system comprising:

a driver workload estimator configured to provide a driver workload estimation signal indicative of the workload of a driver driving the vehicle, wherein the driver workload estimator considers several factors for determining the driver workload estimation signal, said factors are selected from the group consisting of vehicle speed, ambient light, steering angle, lateral acceleration, lane position, driver gaze position, driver pupil diameter, inclement weather, traffic fluidity, road geometry and driver behavior;

a command interpreter responsive to vehicle operation signals and the driver workload estimation signal, said driver workload estimation signal changing a damping ratio and a natural frequency in a filter in the command interpreter to adjust the vehicle operation signals depending on the workload of the driver provided by the driver workload estimation signal, said command interpreter generating at least one desired vehicle response signal; and

a feedback control processor responsive to the driver workload estimation signal, the at least one desired vehicle response signal and at least one measured vehicle response signal, said feedback control processor configured to generate;

at least one vehicle stability signal based on the at least one desired vehicle response signal and at least one measured vehicle response signal;

at least one multiplication factor based on the driver workload estimation signal;

at least one modified stability control signal based on the at least one vehicle stability signal and the at least one multiplication factor; and

a stability control signal to control the vehicle based on one or more of the at least one modified stability control signals.

6. The system according to claim 5 wherein the at least one desired vehicle response signal is a desired yaw rate signal and a desired side-slip signal, the at least one measured vehicle response signal is a yaw rate signal and a side-slip signal, the at least one vehicle stability signal is a yaw rate vehicle stability signal and a side slip vehicle stability signal, the at least one multiplication factor is a yaw rate multiplier factor and a side-slip multiplier factor, the at least one modified stability control signal is a modified yaw rate vehicle stability signal and a modified side slip vehicle stability signal, and wherein the stability control signal is based on a combination of the modified yaw rate vehicle stability signal and the modified side slip vehicle stability signal.

7. A vehicle stability enhancement system configured to provide vehicle stability control for a vehicle, said system comprising:

a driver workload estimator configured to provide a driver workload estimation signal indicative of the workload of a driver driving the vehicle;

a command interpreter responsive to vehicle operation signals and the driver workload estimation signal, said command interpreter generating a desired yaw rate signal and a desired side-slip signal; and

a feedback control processor responsive to the driver workload estimation signal, the desired yaw rate signal, the desired side-slip signal, a measured yaw rate signal and a measured side-slip signal, said feedback control processor configured to generate a stability control signal for controlling the vehicle, said feedback control processor generating a first error signal as the difference between the desired yaw rate signal and the measured yaw rate signal and a second error signal as the difference between the desired side-slip signal and the measured side-slip signal, said feedback control processor including a first look-up table that provides a yaw rate gain signal in response to the yaw rate error signal and a second look-up table that provides a side-slip gain signal in response to the side-slip error signal, said feedback control processor further including a first multiplier that multiplies the yaw rate error signal times the yaw rate gain signal to generate a yaw rate stability signal and a second multiplier that multiplies the side-slip error signal times the side-slip gain signal to generate a side-slip stability signal, said feedback control processor further including a control gain adaptation processor responsive to the driver workload estimation signal and generates a yaw rate multiplier factor and a side-slip multiplier factor, said feedback control processor further including a third multiplier that multiplies the yaw rate stability signal times the yaw rate multiplier factor to generate a modified yaw rate stability signal and a fourth multiplier that multiplies the side-slip stability signal times the side-slip multiplier factor to generate a modified side-slip stability signal.

8. The system according to claim 7 wherein the feedback control processor further includes an adder that adds the modified yaw rate stability signal and the modified side-slip stability signal to generate the stability control signal.

9. The system according to claim 7 wherein the feedback control processor determines whether the vehicle is in an understeer condition before it determines the yaw rate multiplier factor, and sets the yaw rate multiplier factor to 1 if the vehicle is in an understeer condition.

10. The system according to claim 7 wherein the driver workload estimator generates the driver workload estimation signal based on environmental factors.

11. The system according to claim 7 wherein the driver workload estimator generates the driver workload estimation signal based on the speed of the vehicle.

12. The system according to claim 7 wherein the driver workload estimator generates the driver workload estimation signal based on the driver'"'"'s behavior.

13. The system according to claim 12 wherein a driver workload estimation index is generated offline based on the driver'"'"'s behavior where the driver'"'"'s behavior is mapped to driver workload estimation indexes.