Method for the online determination of values of the dynamics of vehicle movement of a motor vehicle

• US 20030191572A1
• Filed: 06/05/2003
• Published: 10/09/2003
• Est. Priority Date: 04/19/2000
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Luders, Ulrich, Frentz, Hubertus Raitz Von, Raste, Thomas, Roll, Georg, Oehler, Rainer
• Granted Patent: US 6,954,691 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• 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
• CPC Class Codes: B62D 6/04 responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel

Abstract

The present invention relates to a method for the online determination of values of driving dynamics for a motor vehicle.

To improve the quality of the control of a motor vehicle and to reduce the demands placed on the driver, the invention discloses a driving dynamics control including the following steps:

Determining estimated output quantities ŷ_m in dependence on determined and/or estimated input quantities u and predetermined or predicted vehicle state variables {circumflex over (x)} and optionally further quantities,

comparing the estimated output quantities ŷ_m with measured output quantities y_m, and

determining the estimated driving dynamics quantities {circumflex over (x)}(t_k/t_k) in dependence on the measurement result and, as the case may be, further criteria.

Claims

1. Method for the online determination of values of driving dynamics for a motor vehicle, characterized by the following steps:

determining estimated output quantities ŷ

_m in dependence on determined and/or estimated input quantities u and predetermined or predicted vehicle state variables {circumflex over (x)} and optionally further quantities,

comparing the estimated output quantities ŷ

_m with measured output quantities ŷ

_m,

determining the estimated driving dynamics quantities {circumflex over (x)}(t_k|t_k) in dependence on the measurement result and, as the case may be, further criteria.

2. Method as claimed in claim 1, characterized by the following step:

model-based determination of the predicted vehicle state variables {circumflex over (x)} in dependence on determined and/or estimated input quantities u and the driving dynamics quantities {circumflex over (x)}(t_k|t_k).

3. Method as claimed in claim 1 or 2, characterized in that the following input quantities u(t)={circumflex over (V)}_x,δ

,F_x;

{circumflex over (F)}_zorF_z,{circumflex over (μ

)}_i or μ

_i are taken into account in the estimation of the predicted vehicle state variables {circumflex over (x)} and in the determination of the driving dynamics quantities {circumflex over (x)}(t_k|t_k), where {circumflex over (V)}_z=estimated longitudinal vehicle speed, δ

=the measured steering angle, F_x=the determined longitudinal tire or wheel forces, {circumflex over (F)}_z=the estimated vertical forces, or F_z=the determined vertical forces, {circumflex over (μ

)}_i=the estimated coefficients of friction for the tire/road contact or μ

_i=the determined coefficients of friction for the tire/road contact.

4. Method as claimed in any one of claims 1 to 3, characterized in that as driving dynamics quantities and the predicted vehicle state variables {circumflex over (x)}=[{circumflex over (V)}_y,{circumflex over ({dot over (ψ

)})}]^T or {circumflex over (x)}=[{circumflex over (V)}_y,{circumflex over ({dot over (ψ

)})},{circumflex over (F)}_d]^T the lateral vehicle speed {circumflex over (V)}_y, the yaw rate {circumflex over ({dot over (ψ

)})} and the disturbing forces {circumflex over (F)}_d, which are estimated as non-measurable input quantities, are determined.

5. Method as claimed in claim 4, characterized in that as other quantities of driving dynamics and of the predicted vehicle state variables {circumflex over (x)}=[{circumflex over (T)}_d,μ

_i]^T the disturbing torques M_d and the coefficients of friction μ

_i are determined as non-measurable input quantities.

6. Method as claimed in any one of claims 1 to 5, characterized in that the predicted vehicle state variables {circumflex over (x)} for the next sampling moment t_k+1 are achieved by integration pursuant the non-linear equation

7. Method as claimed in any one of claims 1 to 6, characterized in that as an output quantity ŷ

_m=[{circumflex over (α

)}_y] the lateral acceleration a_y is estimated.

8. Method as claimed in claim 7, characterized in that as another output quantity ŷ

_m=[{dot over (ψ

)}] the yaw rate {dot over (ψ

)} is estimated.

9. Method as claimed in any one of claims 1 to 6, characterized in that as still other output quantities ŷ

_m=[{circumflex over (F)}_y]^T the lateral tire and wheel forces F_y. are estimated.

10. Method as claimed in any one of claims 1 to 9, characterized in that the output quantities ŷ

_m for the sampling moment t_k are estimated according to the discrete, non-linear equation h_m

ŷ

_m(t_k|t<sub>k−

1</sub>)=h_m({circumflex over (x)}(t_k|t<sub>k−

1</sub>),u_m(t_k))

from the vehicle state variables {circumflex over (x)}(t_k|t<sub>k−

1</sub>) and the input quantities u_m(t_k), where

ŷ

_m estimated state vector of the measurable outputs

{circumflex over (x)} estimated state vector

u_m input vector of the measurable inputs

h_m(.) discrete, non-linear measurement equations

{circumflex over (x)}(t_k|t<sub>k−

1</sub>) estimated signal at the moment t_k, with only information of the last moment t<sub>k−

1</sub> being used

ŷ

(t_k|t<sub>k−

1</sub>) estimated signal at the moment t_k, with only information of the last moment t<sub>k−

1</sub> used

t_k discrete moment.

11. Method as claimed in any one of claims 1 to 10, characterized in that at least one of the estimated output quantities ŷ

_m=[{circumflex over (F)}_y,{circumflex over (α

)}_y,{circumflex over ({dot over (ψ

)})}]^T is compared to at least one of the determined (acquired directly or indirectly by means of sensors) output quantities y_m(t_k)=[F_y,α

_y,{dot over (ψ

)}]^T and the comparison results e(t_k) are sent to a summation point, preferably by way of a gain matrix K, for the correction of the vehicle state variable {circumflex over (x)}(t_k|t<sub>k−

1</sub>), where {circumflex over (x)}(t_k|t<sub>k−

1</sub>)=estimated signal at the moment t_k, with information of the last moment t<sub>k−

1</sub> being used.

12. Method as claimed in any one of claims 1 to 11, characterized in that the gain matrix K at every moment t_k is defined pursuant the relation K(t_k)=ƒ

(Â

,G), where G=information content of the determined (measured) signals and Â

=estimated operating point of the non-linear vehicle model.

13. Method as claimed in any one of claims 1 to 12, characterized in that the correction of the driving dynamics quantities is carried out according to the relation

{circumflex over (x)}(t_k|t_k)={circumflex over (x)}(t_k|t_k−

1)+K(t_k)e(t_k).

14. Method as claimed in any one of claims 1 to 13, characterized by the step:

determining the estimated controlled quantities y_r at the moment t_k by using information of the current moment from the driving dynamics quantities {circumflex over (x)}(t_k|t_k) and the input quantities u_m(t_k) according to the relation ŷ

_r(t_k|t<sub>k−

1</sub>)=h_r({circumflex over (x)}(t_k|t<sub>k−

1</sub>),u_m(t_k)), where u_m(t_k)=vector of the sensed discrete input quantities.

15. Method as claimed in any one of claims 1 to 13, characterized by the step:

determining the estimated controlled quantities y_r at the moment t_k by using information of the last moment from the vehicle state variables {circumflex over (x)}(t_k|t<sub>k−

1</sub>) and the input quantities u_m(t_k) according to the relation y_r(t_k|t<sub>k−

1</sub>)=h_r({circumflex over (x)}(t_k|t<sub>k−

1</sub>),u_m(t_k)), where u_m(t_k)=vector of the sensed discrete input quantities.

16. Method as claimed in any one of claims 1 to 15, characterized by the steps:

determining an estimated sideslip angle {circumflex over (β

)} as a controlled quantity ŷ

_r(t_k|t<sub>k−

1</sub>) or ŷ

_r(t_k|t_k), respectively, comparing the estimated sideslip angle {circumflex over (β

)} with a sideslip angle reference quantity β

_reƒ

, producing an additional yaw torque T_req from the estimated difference between the sideslip reference quantity β

_reƒ

and the sideslip angle {circumflex over (β

)} and a difference between a yaw rate reference quantity {dot over (ψ

)}_reƒ

and a yaw rate {dot over (ψ

)} or {circumflex over ({dot over (ψ

)})} or {dot over (ψ

)}_linear and actuation of at least one wheel brake of the motor vehicle in dependence on the additional yaw torque T_req.

17. Method as claimed in any one of claims 1 to 16, characterized in that the sideslip angle reference quantity β

_reƒ

is an activation threshold that is variable in dependence on the speed V_x, e.g. V_reƒ

, of the vehicle.

18. Method as claimed in any one of claims 1 to 16, characterized in that the sideslip angle reference quantity β

_reƒ

is determined in a dynamic model, in particular the one-track model.

19. Method as claimed in any one of claims 1 to 18, characterized in that the yaw rate {circumflex over ({dot over (ψ

)})} is estimated as a controlled quantity ŷ

_r(t_k|t<sub>k−

1</sub>) or ŷ

_r(t_k|t_k), respectively.

20. Method as claimed in any one of claims 1 to 19, characterized in that the estimated yaw rate {circumflex over ({dot over (ψ

)})} is produced in dependence on a measured yaw rate {dot over (ψ

)} of reduced quality or a substitute signal {dot over (ψ

)}_linear.

21. Method as claimed in any one of claims 1 to 21, characterized in that the additional yaw torque T_req is produced in dependence on the measured yaw rate {dot over (ψ

)}.

22. Method as claimed in any one of claims 1 to 20, characterized in that the king pin inclinations of the tires for the front axle {circumflex over (α

)}_v and the rear axle {circumflex over (α

)}_h are estimated as controlled quantity ŷ

_r(t_k|t<sub>k−

1</sub>) or ŷ

_r(t_k|t_k), respectively.

23. Driving dynamics control, especially ESP control or suspension control, characterized by a method as claimed in any one of claims 1 to 22.

24. Driving dynamics control, in particular as claimed in claim 23, characterized by a first determining unit (402) for estimating the controlled quantities {dot over (ψ

)} and/or {circumflex over (α

)}_v, {circumflex over (α

)}_h from the input quantities V_x,δ

,F_x,{dot over (ψ

)},{circumflex over (μ

)},α

_y,{circumflex over (F)}_z, and/or, if necessary, other quantities F_z,{dot over (ψ

)}_linear, deactivation logic (405) for deactivating the sideslip angle control in dependence on the input quantities {circumflex over (α

)}_v, {circumflex over (α

)}_h and/or quantities representative of the driving situations of the motor vehicle, such as rearward driving, driving around a steep turn, and the like second determining unit (404) for the adaptive sideslip angle torque calculation from the input quantities

{circumflex over (β

)}, β

_reƒ

,{dot over (ψ

)},V_reƒ

or Vx,{circumflex over (μ

)}_i, respectively

third determining unit (406) for the arbitration of an additional yaw torque T_req. from the yaw torque T<sub>reg—

ESP</sub> and T<sub>reg—

beta</sub>.

25. Driving dynamics control as claimed in claim 23 or 24, characterized in that the first determining unit (402) is connected to a vertical force model (403) for estimating the vertical forces {circumflex over (F)}_z of the motor vehicle from the input quantities α

_y,{circumflex over (α

)}_x.

26. Driving dynamics control as claimed in any one of claims 23 to 25, characterized in that the second determining unit (404) is connected to a reference model (401) for determining the activation threshold which is variable responsive to the speed V_x or V_reƒ

, respectively.

27. Use of the sideslip angle determined according to the method or in the driving dynamics control as claimed in any one of claims 1 to 26 for the purpose of active steering intervention.