METHOD FOR CONTROLLING AN ANTI-LOCK BRAKING SYSTEM

Abstract

A method for controlling an anti-lock braking system in a motor vehicle. The control is carried out based on a wheel slip of at least one of the wheels. A wheel circumferential speed and a groundspeed in the longitudinal direction of the wheel being taken into account to compute the wheel slip. The groundspeed being estimated in terms of value and direction based on signals from sensors that describe all six degrees of freedom in space.

Claims

1. A method for controlling an anti-lock braking system in a motor vehicle, comprising the following: controlling the anti-lock braking system based on a wheel slip of at least one of wheel of the motor vehicle, wherein a wheel circumferential speed and a groundspeed in a longitudinal direction of the wheel are taken into account to compute the wheel slip, the groundspeed being estimated in terms of value and direction based on signals from sensors of the motor vehicle that describe all six degrees of freedom in space.

2. The method as recited in claim 1, wherein the wheel circumferential speed, the groundspeed, and a difference between the wheel circumferential speed and the groundspeed are put into perspective to compute the wheel slip.

3. The method as recited in claim 1, wherein the groundspeed is estimated in terms of value and direction based on signals from three acceleration sensors and three rotational speed sensors.

4. The method as recited in claim 3, wherein the estimation of the groundspeed is carried out using at least one element that is selected from: Luenberger observer, Kalman filter, particle filter, neural network.

5. The method as recited in claim 3, wherein at least one further sensor is used to support the algorithm for carrying out the method.

6. The method as recited in claim 5, wherein the at least one further sensor is selected from a set that includes: a steering angle sensor, a wheel rotational speed sensor, a brake pressure sensor.

7. A system for controlling an anti-lock braking system, the system configured to: control the anti-lock braking system based on a wheel slip of at least one of wheel of the motor vehicle, wherein a wheel circumferential speed and a groundspeed in a longitudinal direction of the wheel are taken into account to compute the wheel slip, the groundspeed being estimated in terms of value and direction based on signals from sensors of the motor vehicle that describe all six degrees of freedom in space.

8. The system as recited in claim 7, wherein the system includes a controller.

9. A non-transitory machine-readable memory medium on which is stored a computer program having program code for controlling an anti-lock braking system in a motor vehicle, the program code, when executed by a processing unit, causing the processing unit to perform the following: controlling the anti-lock braking system based on a wheel slip of at least one of wheel of the motor vehicle, wherein a wheel circumferential speed and a groundspeed in a longitudinal direction of the wheel are taken into account to compute the wheel slip, the groundspeed being estimated in terms of value and direction based on signals from sensors of the motor vehicle that describe all six degrees of freedom in space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a simplified representation of a comparison of a conventional control loop with a control loop according to one example embodiment of the present invention.

[0026] FIG. 2 shows a schematic representation of a motor vehicle with the aid of one specific example embodiment of the system for carrying out the method in accordance with the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0027] The present invention is illustrated schematically in the figures on the basis of specific embodiments and is described in greater detail in the following with reference to the figures.

[0028] FIG. 1 shows on the left-hand side a control loop 10 for carrying out a conventional method for controlling an anti-lock braking system device 12. Next to it, the representation shows a motor vehicle 14. Variables 16, such as for example wheel speed(s), longitudinal acceleration, yaw rate, steering angle, etc., which are measured and provided by various sensors, are output from motor vehicle 14 into anti-lock braking system device 12, which includes a controller. The anti-lock braking system device outputs a wheel torque as output variable 18.

[0029] On the right-hand side of the representation, a control loop 30 is illustrated, with the aid of which a method of the type presented here may be carried out. The representation shows an anti-lock braking system device 32 and a motor vehicle 34. The vehicle outputs as variables 36, in particular as reference variables: wheel speed, 6D sensor variables, steering angle, etc. Anti-lock braking system device 32 outputs a wheel torque as output variable 38.

[0030] FIG. 2 shows in a schematic representation a motor vehicle that as a whole is identified with reference numeral 50. This vehicle 50 includes two driven wheels 52, 54 and two wheels 56, 58 running together. The presented method is typically carried out for one or multiple driven wheels 52, 54, only wheel 52 being discussed in greater detail for the purpose of simplifying the illustration.

[0031] This wheel 52 is now associated with a wheel circumferential sensor 60, with the aid of which the wheel circumferential speed or a variable representing the wheel circumferential speed may be detected. A corresponding wheel circumferential signal 68 is output. Furthermore, wheel 52 is associated with three acceleration sensors 64 and three rotational speed sensors 66. Acceleration sensors 64 provide first signals 70 that describe the acceleration information in three spatial directions. Correspondingly, the rotational speed sensors provide second signals 72 that carry the rotational speed information about three spatial axes.

[0032] Instead of acceleration sensors 64 and rotational speed sensors 66, at least one radar sensor and/or at least one video camera may also be used.

[0033] Signals 70 and 72 as well as wheel circumferential signal 68 are input into a system 80 that uses these to compute wheel slip 82.

[0034] This wheel slip is the input variable or the reference variable of a control and is input into a controller 84 that uses same to ascertain an actuating variable 86, with the aid of which an anti-lock braking system of motor vehicle 50 is activated or acted on.

[0035] It is to be noted that the groundspeed of wheel 52 is estimated in terms of value and direction based on signals 70 and 72 from sensors 64 and 66, which describe all six degrees of freedom in space. For this purpose, three acceleration sensors 64 and three rotational speed sensors 66 are provided in this case.