Device and Method for the Adaptation of an Actuating Threshold of a Braking Element of a Brake-By-Wire Brake of a Motor Vehicle

Abstract

A method for the adaptation of an actuating threshold of a braking element of a brake-by-wire brake of a motor vehicle determines initiation of a braking torque of the brake-by-wire brake at a predetermined actuating travel of the braking element. A control unit regulates the brake-by-wire brake, wherein the actuating travel of the braking element is sensed continuously by way of a travel sensor when the braking element is manually actuated. A predetermined constant actuating force is set or an actuating force is determined continuously by way of a sensor. Furthermore, a characteristic curve is determined from at least the sensed actuating travel and the actuating force by way of the control unit and a characteristic property, in particular a maximum of a second derivative of the characteristic curve, is determined by way of the control unit.

Claims

1.-9. (canceled)

10. A method for the adaptation of an actuating threshold of a braking element of a brake-by-wire brake of a motor vehicle, which determines an initiation of a braking torque of the brake-by-wire brake in the case of a predetermined actuating travel of the braking element, using a control unit for regulating the brake-by-wire brake, the method comprising: detecting continuously the actuating travel of the braking element by way of a distance sensor, defining a predetermined constant actuating force or determining continuously an actuating force when the braking element is manually actuated, by way of a sensor, determining a characteristic curve on the basis of at least the detected actuating travel and the actuating force by way of the control unit, determining a maximum of a second derivative as a characteristic property of the characteristic curve by way of the control unit, defining a pressure point which corresponds to an actuating travel in the case of the maximum of the second derivative as the characteristic property of the characteristic curve by way of the control unit, adapting the actuating threshold of the braking element to the pressure point or to an actuating travel, which corresponds to a sum of a predetermined travel and the pressure point, by way of the control unit.

11. The method according to claim 10, wherein, during the manual actuation, the braking element is actuated using a constant actuating force.

12. The method according to claim 11, wherein, during the determination of the characteristic curve, an actuating travel-time characteristic curve is determined and, during the determination of the maximum of the second derivative as the characteristic property, an actuating acceleration is determined on the basis of a second derivative of the actuating travel by way of the control unit.

13. The method according to claim 10, wherein the sensor is a force sensor arranged at the braking element and, during the manual actuation, an actuating force of the braking element is determined.

14. The method according to claim 13, wherein, during the determination of the characteristic curve, an actuating force-actuating travel characteristic curve is determined on the basis of the detected actuating travel and the detected actuating force by way of the control unit.

15. The method according to claim 14, wherein, during the adaptation, the actuating threshold of the braking element is continuously adapted by way of the control unit.

16. A device for the adaptation of an actuating threshold of a braking element of a brake by-wire brake of a motor vehicle, which determines an initiation of a braking torque of the brake-by-wire brake in the case of a predetermined actuating travel of the braking element according to the method of claim 10, the device comprising: a control unit for regulating the brake-by-wire brake, and a distance sensor for detecting the actuating travel of the braking element, wherein a characteristic curve is determinable by the control unit on the basis of at least the detected actuating travel, wherein a maximum of a second derivative of the characteristic curve is determinable by the control unit as a characteristic property, wherein a pressure point which corresponds to an actuating travel in the case of the characteristic property is defined by the control unit, and wherein an actuating threshold of the braking element is adapted by the control unit to the pressure point or to an actuating travel, which corresponds to a sum of a predetermined travel and the pressure point.

17. The device according to claim 16, wherein the characteristic curve is an actuating travel-time characteristic curve.

18. The device according to claim 16, wherein a force sensor for continuously detecting an actuating force of the braking element is arranged at the braking element, and wherein the characteristic curve is an actuating force-actuating travel characteristic curve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other advantageous refinements of the disclosure will be described in more detail hereinafter together with the description of the preferred embodiment of the disclosure on the basis of the figures.

[0019] FIG. 1 shows a schematic view of a device for the adaptation of an actuating threshold of a braking element of a brake-by-wire brake of a motor vehicle; and,

[0020] FIG. 2 shows an actuating force-actuating travel characteristic curve and a first and a second derivative of an actuating force-actuating travel characteristic curve having a pressure point and an actuating threshold.

[0021] The schematic figures are given by way of example. Identical reference signs in the figures indicate identical functional and/or structural features.

DETAILED DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 shows a schematic view of a device for the adaptation of an actuating threshold 10 of a braking element 1 of a brake-by-wire brake of a motor vehicle, which determines an initiation of the braking torque of the brake-by-wire brake in the event of a predetermined actuating travel of the braking element 1. The device comprises a control unit 2 for regulating the brake-by-wire brake. The control unit 2 may comprise or be part of the motor vehicle's Electronic Control Unit (ECU) or Electronic Control Module (ECM), and/or may comprise a processor or microprocessor, associated with a memory for storing software and/or logic for executing the methods disclosed herein. In addition, a distance sensor 3 for detecting the actuating travel of the braking element 1 and a force sensor 7 for continuously detecting an actuating force of the braking element 1 are provided at the braking element 1. A characteristic curve 5 is determinable here on the basis of the detected actuating travel and the detected actuating force by way of the control unit 2 and a maximum of a second derivative of the characteristic curve 5 is determinable by way of the control unit 2. The characteristic curve is an actuating force-actuating travel characteristic curve. Furthermore, a pressure point 6, which corresponds to an actuating travel at the maximum of the second derivative of the characteristic curve 5, is definable by way of the control unit 2. In addition, an actuating threshold 10 of the braking element 1 is adaptable to an actuating travel, which corresponds to a sum of a predetermined travel and the pressure point 6, by way of the control unit 2.

[0023] Accordingly, the device for carrying out a method for the adaptation of an actuating threshold 10 of a braking element 1 of a brake-by-wire brake of a motor vehicle, which determines an initiation of a braking torque of the brake-by-wire brake in the case of a predetermined actuating travel of the braking element (1), comprises a control unit 2 for regulating the brake-by-wire brake, in which initially the actuating travel of the braking element 1 is continuously detected by way of a distance sensor 3 when the braking element 1 is manually actuated. Furthermore, a characteristic curve 5 is determined on the basis of at least the detected actuating travel by way of the control unit 2, and a maximum of a second derivative of the characteristic curve 5 is determined by way of the control unit 2. A pressure point 6 is then defined, which corresponds to an actuating travel at the maximum of the second derivative of the characteristic curve 5, by way of the control unit 2. Thereupon, by way of the control unit 2, the actuating threshold 10 of the braking element 1 is adapted to the pressure point 6 or to an actuating travel, which corresponds to a sum of a predetermined travel and the pressure point 6.

[0024] During the continuous detection, an actuating force of the braking element 1 is detected, and, during the determination of the characteristic curve 5, by way of the control unit 2, an actuating force-actuating travel characteristic curve is determined on the basis of the detected actuating travel and the detected actuating force by way of the control unit 2. Furthermore, during the adaptation, the actuating threshold 10 of the braking element is continuously adapted.

[0025] FIG. 2 shows an actuating force-actuating travel characteristic curve 50 and a first derivative 51 and second derivative 52 of an actuating force-actuating travel characteristic curve 51 having a pressure point 6 and an actuating threshold 10. In addition, an actuating threshold 10 of the braking element 1 is adapted to an actuating travel, which corresponds to a sum of a predetermined travel and the pressure point 6, by way of the control unit 2.

[0026] The disclosure is not restricted in its embodiment to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable, which make use of the described solution even in fundamentally different embodiments.