Method for increasing the driving stability of a vehicle

• US 20070185638A1
• Filed: 01/05/2007
• Published: 08/09/2007
• Est. Priority Date: 07/20/2004
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Lohninger, Roland, Odenthal, Dirk
• Granted Patent: US 7,330,785 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/17555 specially adapted for enhancing driver or passenger comfort, e.g. soft intervention or pre-actuation strategies
• CPC Class Codes: B60W 40/11 Pitch movement
• CPC Class Codes: B60W 40/112 Roll movement
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

A method for increasing the directional stability of a motor vehicle is provided, as well as a corresponding device, and a corresponding computer program product. A model-supported pilot control is used to determine a stabilizing yaw torque, which is applied to the motor vehicle to influence the yaw torque of the motor vehicle.

Claims

1. A method for providing directional stability for a motor vehicle by influencing a yaw torque of the vehicle, the method comprising the acts of:

determining a stabilizing yaw torque using a model-supported pilot control; and

applying the stabilizing yaw torque to the motor vehicle to influence the yaw torque of the vehicle.

2. The method according to claim 1, wherein the model-supported pilot control is based on a single-track model that considers longitudinal dynamics.

3. The method according to claim 2, wherein at least one of lateral dynamics and yaw dynamics are decoupled from the longitudinal dynamics.

4. The method according to claim 2, wherein the single-track model is simulated as a parametric linear time-invariant system, and wherein at least longitudinal-dynamic variables of velocity and longitudinal acceleration are interpreted as varying parameters.

5. The method according to claim 4, wherein chronological changes of the velocity are neglected while the longitudinal acceleration is handled as a varying parameter.

6. The method according to claim 1, wherein using the model-supported pilot control includes a performing pilot control method, and wherein an effective steering angle, a vehicle reference velocity, and a value for a longitudinal acceleration are used as input variables for the pilot control method.

7. The method according to claim 6, wherein at least one of a longitudinal torque and a longitudinal force distribution is considered an input variable for the pilot control method, wherein at least one of the longitudinal torque and the longitudinal force distribution is calculated from at least one of a longitudinal acceleration and a mean longitudinal slip at a front axle and a rear axle.

8. The method according to claim 6, wherein at least one of wheel speeds, mass, yaw moment of inertia, center of gravity position, axle slip angle, and a coefficient of friction is considered in the model as an input variable for the pilot control method.

9. The method according to claim 1, wherein at least one differential variable is used in the model-supported pilot control as a control signal for the stabilizing yaw torque.

10. The method according to claim 1, wherein a setpoint yaw rate is determined from a driver-preset steering angle and the setpoint yaw rate is used to calculate at least one differential value, wherein the differential value is calculated via an inverse single-track model into at least one of an angle value and a torque value and via an inverse expanded single-track model into at least one of an angle value and a torque value.

11. The method according to claim 10, wherein the at least one differential value, superimposed as a correcting angle preset on the driver-preset steering angle, is converted into at least one of an active front wheel steering and an active rear wheel steering.

12. The method according to claim 1, wherein at least one of a proportional differential variable and a differential variable amplified using a PID regulator is used as a control signal for the stabilizing yaw torque in the model-supported pilot control.

13. The method according to any one of claims 1-9, wherein using the model-supported pilot control includes:

subjecting an effective steering angle, after reshaping by a single-track model, to a regulated pilot control using a PID regulator and a single-track model having longitudinal dynamics in a feedback loop.

14. The method according to any one of claims 1-9, wherein an effective steering angle is processed in a structure having two degrees of freedom, wherein the effective steering angle is processed by feeding back a differential signal from the output of two branches of a feedback loop to the effective steering as an input signal.

15. The method according to claim 14, wherein the differential signal is fed back from output signals of a first branch containing a filter function and of a second branch having a series circuit including a single-track model having longitudinal dynamics and a product of the filter function and an inverse transfer function of a single-track model.

16. The method according to claim 1, wherein using the model-supported pilot control includes storing stationary values to represent a model.

17. The method according to claim 1, wherein the model-supported pilot control uses actuators for lateral torque distribution of at least one of a front axle and a rear axle, the actuators being provided in regulators.

18. The method according to claim 1, wherein the model-supported control is activated event-discretely, an event-discrete startup being caused by a corresponding signal.

19. The method according to claim 1, further comprising:

detecting deviations as vehicle properties that are to be unaffected by correction and compensation measures.

20. An apparatus for providing directional stability for a motor vehicle by influencing a yaw torque of the motor vehicle, the apparatus comprising:

means for performing a model-supported pilot control to determine a stabilizing yaw torque; and

at least one actuator for transmitting at least one output signal corresponding to the model-supported pilot control to influence the yaw torque of the motor vehicle.

21. The apparatus according to claim 20, further comprising:

means for providing permanent and nonvolatile storage of a single-track model, an inverse single-track model, and an inverse expanded single-track model, wherein longitudinal-dynamic influences on lateral dynamics and yaw dynamics of the motor vehicle are simulated in the expanded single-track model.

22. The apparatus according to any one of claims 20 and 21, wherein the means for performing the model-supported pilot control includes means for connecting to at least one of an active front wheel steering and an active rear wheel steering.

23. A computer program product, which comprises a computer-readable medium containing instructions for controlling a system to influence a yaw torque of a motor vehicle, the system operable to execute the instructions, the instructions comprising:

instructions for obtaining at least one input variable from at least one of a sensor system, a regulating system, and a driver assistance system; and

instructions for applying an additional stabilizing yaw torque to influence the yaw torque of the motor vehicle, wherein the additional stabilizing yaw torque is applied based on a model-supported pilot control and a processing of the at least one input variable.

24. A computer program product according to claim 23, wherein the instructions for obtaining at least one input variable comprise instructions for obtaining at least three input variables.

25. A computer program product according to claim 23, wherein the instructions further comprise:

instructions for determining the additional stabilizing yaw torque using the model-supported pilot control; and

determining at least one actuator control variable for at least one actuator as an output signal based on the additional stabilizing yaw torque.