Method and brake system for controlling the braking process in a motor vehicle

• US 20030107265A1
• Filed: 01/16/2003
• Published: 06/12/2003
• Est. Priority Date: 07/18/2000
• Status: Active Grant

• Current Assignee: Pacifica Group Technologies Pty Limited
• Original Assignee: Pacifica Group Technologies Pty Limited
• Inventors: Arnold, Armin
• Granted Patent: US 6,783,194 B2
• Time in Patent Office: Days
• US Class Current: 303/139
• 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
• CPC Class Codes: B60T 8/17636 Microprocessor-based systems

Abstract

A wheelslip is calculated from wheel speed, recorded by speed sensors (6), by a controller (8). A pre-set value for the wheelslip is regulated by means of a proportional controller. Parallel thereto, a set brake pressure for the wheel brakes (3) is fixed, which is determined by the controller (8), by means of the instantaneous wheel torque (Mmomentan) transferred to the ground by the particular wheel (2).

Claims

1. A method for controlling the braking process in a motor vehicle, wherein

brake actuation signals are converted into brake application forces,

the wheel speeds of at least some of the wheels are transmitted to a control system,

a wheel slip is calculated by the control system from the wheel speeds, and a predefined value is set for the wheel slip, and

the predefined value for the wheel slip is set by a proportional control and a setpoint brake pressure which is defined in parallel therewith, and

by setting the control to a longitudinal slip above the maximum of the coefficient of static friction, the lateral guiding force of the wheel is reduced, and the driving behavior of the motor vehicle is thus stabilized.

2. The method as claimed in claim 1, wherein the predefined value for the wheel slip is set by means of a proportional plus derivative control.

3. The method as claimed in claim 1, wherein the predefined value for the wheel slip is set by means of a proportional integral control with a very small integral component.

4. The method as claimed in claim 1, wherein the setpoint brake pressure is determined by means of the wheel torque which is transmitted from the wheel to the underlying surface instantaneously.

5. The method as claimed in claim 1, wherein the wheel torque which is transmitted from the wheel to the underlying surface instantaneously is determined from the torque balance at the wheel.

6. The method as claimed in claim 1, wherein the wheel torque which is transmitted from the wheel to the underlying surface instantaneously is determined according to the equation M_inst.=−

M_brake+{dot over (ω

)}·

Θ

, wherein M_brake is the brake torque caused by the brake, {dot over (ω

)} is the wheel acceleration values and Θ

is the wheel inertia values, and in that the defined setpoint brake pressure with which intervention into the brake control system is carried out is calculated using a wheel brake pressure which corresponds to this transmitted wheel torque.

7. A brake system with control of the braking process in a motor vehicle, comprising:

wheel speed sensors which sense the speeds of the wheels of the motor vehicle and transmit them to a control system,

a control system which evaluates the sensor signals, calculates slip values of the individual wheels from the wheel speeds and generates control signals for the wheel brakes, and which contains a controller which is embodied as a proportional controller and which controls a predefined value for the wheel slip,

a setpoint brake pressure being determined by the control system and said setpoint brake pressure being used, in addition to the adjustment, to set the brake pressure at the wheel brakes, and

having brake actuators which convert the control signals into activation operations of the wheel brakes, wherein

the control system sets the control to a longitudinal slip lying above the maximum of the coefficient of static friction and as a result reduces the lateral guiding force of the wheel and stabilizes the driving behavior of the motor vehicle.

8. The brake system as claimed in claim 7, wherein the setpoint brake pressure is determined by the control system by means of the wheel torque which is transmitted from the respective wheel to the underlying surface instantaneously.

9. The brake system as claimed in claim 7, wherein the wheel torque which is transmitted from the respective wheel to the underlying surface instantaneously is determined by the control system from the torque balance at the wheel.

10. A method for controlling the braking process in a motor vehicle, comprising the steps of:

converting brake actuation signals into brake application forces,

transmitting the wheel speeds of at least some of the wheels to a control system,

calculating a wheel slip by the control system from the wheel speeds, and setting a predefined value for the wheel slip,

setting the predefined value for the wheel slip by a proportional control and a setpoint brake pressure which is defined in parallel therewith.

11. The method as claimed in claim 10, wherein the predefined value for the wheel slip is set by means of a proportional plus derivative control.

12. The method as claimed in claim 10, wherein the predefined value for the wheel slip is set by means of a proportional integral control with a very small integral component.

13. The method as claimed in claim 10, wherein the setpoint brake pressure is determined by means of the wheel torque which is transmitted from the wheel to the underlying surface instantaneously.

14. The method as claimed in claim 10, wherein the wheel torque which is transmitted from the wheel to the underlying surface instantaneously is determined from the torque balance at the wheel.

15. The method as claimed in claim 10, wherein the wheel torque which is transmitted from the wheel to the underlying surface instantaneously is determined according to the equation M_inst.=−

M_brake+{dot over (ω

)}·

Θ

, wherein M_brake is the brake torque caused by the brake, {dot over (ω

)} is the wheel acceleration values and Θ

is the wheel inertia values, and in that the defined setpoint brake pressure with which intervention into the brake control system is carried out is calculated using a wheel brake pressure which corresponds to this transmitted wheel torque.

16. The method as claimed in claim 10, wherein, by setting the control to a longitudinal slip above the maximum of the coefficient of static friction, the lateral guiding force of the wheel is reduced, and the driving behavior of the motor vehicle is thus stabilized.