Vehicle stabilizing device and method for modifying brake pressures

• US 6,438,482 B1
• Filed: 05/25/2001
• Issued: 08/20/2002
• Est. Priority Date: 05/12/1998
• Status: Expired due to Term

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG), DaimlerChrysler AG (Mercedes-Benz Group AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG), Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Baumann, Mathias, Haussmann, Marc, Herrmann, Torsten, Klingel, Ralph
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Donnelly, Arthur D.
• Application Number:
  US09/674,765
• Time in Patent Office: 452 Days
• Field of Search: 701/70, 701/75, 701/78, 303/140, 303/154, 303/155, 303/156, 303/157, 303/167, 303/146
• US Class Current: 701/70
• CPC Class Codes: B60T 2270/304 during driver brake actuation
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02

Abstract

The present invention relates to a vehicle stabilizing device and a method for modifying brake pressures on wheels of a vehicle according to input data. To achieve an optimum from the driver'"'"'s desire to brake, the vehicle stabilization, the steerability of the vehicle, and from the pedal and sound comfort, the present invention discloses a variation of the brake pressures on at least one wheel according to a way of influencing an intervention unit that provides a plurality of influencing cycles or influencing strategies, the said influencing being determined by the brake pressure effected by the driver.

Claims

1. Vehicle stabilizing ESP device for modifying brake pressures on wheels of a vehicle according to input data, comprising:

means for varying the brake pressure on at least one wheel in a way that influences an intervention unit that provides a number of influencing strategies, wherein the influencing strategies are defined by the brake pressure effected by the driver,

wherein the intervention unit includes means for determining an additional torque (M_G) about the vertical axis of the vehicle from actual and nominal rotation data, means for determining a brake pressure apportioning in the case of pressure increase (P_auf) or pressure reduction (P_ab) on a front wheel or rear wheel, means to determine the actual brake pressure (P_ab,ref, P_auf,ref) and the driver brake pressure (P_main), and means for determining at least one top limit value (p_slip) and one bottom limit value (P_lim).

2. Vehicle stabilizing device as claimed in claim 1, wherein the intervention unit includes means for producing signals for a pressure requirement after a pressure reduction or pressure increase of the brake pressures, which pressure requirement effects a predetermined torque of the vehicle, and outputs corresponding control commands to the actuators.

3. Vehicle stabilizing device as claimed in claim 2, wherein the pressure requirement for the pressure increase is limited to a top value to which corresponds a maximum slip of approximately 80% slip on the wheel.

4. Vehicle stabilizing device as claimed in claim 2, wherein the pressure requirement for the pressure reduction is fixed to values for the bottom limit pressure P_lim of generally bar for the front axle and generally 5 bar for the rear axle.

5. Vehicle stabilizing device as claimed in claim 2, wherein the pressure reduction is split up linearly over a defined number of time steps.

6. Vehicle stabilizing device as claimed in claim 1, wherein the intervention unit, in a first influencing cycle, outputs signals to one or more actuators for a pressure variation that effects the torque of the vehicle, wherein the signals effect a pressure increase up to, but not exceeding, the driver'"'"'s initial pressure on at least one wheel.

7. Vehicle stabilizing device as claimed in claim 6, wherein the intervention unit further includes means for generating a second influencing cycle output signals to the actuators for a pressure variation that effects the torque of the vehicle, the said signals effecting a pressure increase up to maximally the driver'"'"'s initial pressure on at least one wheel and a pressure reduction until minimally the bottom limit brake pressure on at least one other wheel.

8. Vehicle stabilizing device as claimed in claim 6, wherein the intervention unit, in a third influencing cycle, outputs signals to the actuators for influencing the torque of the vehicle, the signals effecting a pressure increase in excess of the driver'"'"'s initial pressure on at least one wheel and a pressure reduction until minimally the bottom limit brake pressure on at least one other wheel.

9. Vehicle stabilizing device as claimed in claim 8, wherein the intervention unit, in a fourth influencing cycle, outputs signals to the actuators for influencing the torque of the vehicle, the signals effecting a pressure increase in excess of the driver'"'"'s initial pressure on at least one other wheel.

10. Vehicle stabilizing device as claimed in claim 1, wherein the pressure increase or pressure reduction on the wheels are selected according to the following table

11. Vehicle stabilizing method for modifying brake pressures on wheels of a vehicle according to input data, comprising the step of:

varying the brake pressures on at least one wheel according to influencing cycles strategies determined as a function of driver brake pressure,

wherein the brake pressure that effects a torque about the vertical axis of the vehicle, under the conditions

P_auf,m<

P_slip

and

P_auf,m<

P_main

wherein

P_auf,m=maximum pressure increase requirement

P_slip=top limit brake pressure

P_main=driver brake pressure, is increased until P_auf=P_auf,m in dependence on an oversteering or understeering driving behavior of the vehicle of the curve-outward front wheel or the curve-inward rear wheel.

12. Method as claimed in claim 11, wherein the brake pressure that effects a torque about the vertical axis of the vehicle, under the conditions

P_auf,m< P_slip

and

P_auf,m<

P_main

wherein

P_auf,m=maximum pressure increase requirement

P_slip=top limit brake pressure

P_main=driver brake pressure, is increased until P_auf=P_auf,m in dependence on an oversteering or understeering driving behavior of the vehicle of the curve-outward front wheel or the curve-inward rear wheel.

13. Method as claimed in claim 11, wherein under the conditions

P_ab,ref>

P_lim and P_ab,ref<

P_main

wherein

P_ab,ref=actual brake pressure of the pressure reduction wheel

P_lim=bottom limit brake pressure

P_main=driver brake pressure, the brake pressure on the curve-outward front wheel or on the curve-inward rear wheel is increased according to

14. Method as claimed in claim 11, wherein, the pressure requirement for the pressure increase is limited to a top value (P_slip) to which corresponds a maximum slip of approximately 80% slip on the wheel.

15. Method as claimed in claim 11, wherein the pressure requirements for the pressure reduction in dependence on the front or rear axle of the vehicle where the intervention is effected are fixed to preferably constant values for the bottom limit pressure P_lim.

16. Method as claimed in claim 11, wherein the pressure reduction is apportioned linearly over a defined number of n time steps.

17. Method as claimed in claim 16, wherein the pressure reduction requirement for the time step i is determined according to the relation

18. Vehicle stabilizing ESP device for modifying brake pressures on wheels of a vehicle according to input data, comprising:

means for varying the brake pressure on at least one wheel in a way that influences an intervention unit that provides a number of influencing strategies, wherein the influencing strategies are defined by the brake pressure effected by the driver,

wherein the pressure increase or pressure reduction on the wheels are selected according to the following table

19. Vehicle stabilizing method for modifying brake pressures on wheels of a vehicle according to input data, comprising the step of:

varying the brake pressures on at least one wheel according to influencing cycles strategies determined as a function of driver brake pressure,

wherein the brake pressure that effects a torque about the vertical axis of the vehicle, under the conditions

P_auf,m<

P_slip and P_auf,m≧

P_main

or

P_auf,m≧

P_slip and P_slip≧

P_main

or

P_auf,m≧

P_slip and P_slip<

P_main,

wherein

P_auf,m=maximum pressure increase requirement

P_slip=top limit brake pressure

P_main=driver brake pressure,

and under the condition

P_ab,ref≦

P_lim

wherein

 

P_ab,ref=actual brake pressure of pressure reduction wheel

 

P_lim=bottom brake pressure,

is increased until P_auf=P_auf,m and for P_auf,m ≧

P_slip until P_slp in dependence on an oversteering or understeering driving behavior of the vehicle of the curve-outward front wheel or the curve-inward rear wheel.

20. Vehicle stabilizing method for modifying brake pressures on wheels of a vehicle according to input data, comprising the step of:

varying the brake pressures on at least one wheel according to influencing cycles strategies determined as a function of driver brake pressure

wherein the brake pressure that effects a torque about the vertical axis of the vehicle, under the condition

P_auf,m<

P_slip and P_aufm≧

P_main

or

P_auf,m≧

P_slip and P_slip≧

P_main

or

P_auf,m≧

P_slip and P_slip<

P_main,

wherein

P_auf,m=maximum pressure increase requirement

P_slip=top limit brake pressure

P_main=driver brake pressure, is increased in dependence on an oversteering driving behavior of the vehicle on the curve-outward front wheel until

P_auf=P_main

or is limited to

P_auf=P_slip

when P_auf,m≧

P_slip and P_slip<

P_main is satisfied and is lowered on the curve-inward rear wheel until

P_ab=P_ab,m

wherein

P_ab=pressure decrease in the reduction case

P_ab,m=maximum pressure reduction requirement.

21. Vehicle stabilizing method for modifying brake pressures on wheels of a vehicle according to input data, comprising the step of:

varying the brake pressures on at least one wheel according to influencing cycles strategies determined as a function of driver brake pressure,

wherein the brake pressure that effects a torque about the vertical axis of the vehicle, under the condition

P_auf,m<

P_slip and P_auf,m≧

P_main

or

P_auf,m≧

P_slip and P_slip≧

P_main

or

P_auf,m≧

P_slip and P_slip<

P_main,

wherein

P_auf,m=maximum pressure increase requirement

P_slip=top limit brake pressure

P_main=driver brake pressure, is increased in dependence on an understeering driving behavior of the vehicle on the curve-inward rear wheel until

P_auf=P_main

or is limited to

P_auf=P_slip

when P_auf,m≧

P_slip and P_slip<

P_main is satisfied and is lowered on the curve-outward

front wheel until

P_ab=P_ab,m

wherein

P_ab=pressure decrease in the reduction case

P_ab,m=the maximum pressure reduction requirement.

22. Vehicle stabilizing method for modifying brake pressures on wheels of a vehicle according to input data, comprising the step of:

varying the brake pressures on at least one wheel according to influencing cycles strategies determined as a function of driver brake pressure,

wherein under the conditions

P_ab,ref>

P_lim and P_ab,ref≦

P_main

wherein

P_ab,ref=actual brake pressure of the pressure reduction wheel

P_lim=bottom limit brake pressure

P_main=driver brake pressure, the brake pressure on the curve-outward front wheel or on the curve-inward rear wheel is increased according to