BRAKING SYSTEM FOR AN AUTONOMOUS VEHICLE

Abstract

A braking system in an at least partially autonomous vehicle, having one vehicle wheel brake per vehicle wheel and having a primary brake regulation system and a redundant secondary brake regulation system. One hydraulic actuator for actuating the vehicle brake is provided per vehicle wheel in a first vehicle axle which actuator is assigned to both the primary brake regulation system and also the secondary brake regulation system. One electromechanical primary actuator per vehicle wheel is assigned to the primary brake regulation system in the second vehicle axle and one electromechanical secondary actuator is assigned to the secondary brake regulation system.

Claims

1. A braking system in an at least partially autonomous vehicle, comprising: one vehicle wheel brake per vehicle wheel, a primary brake regulation system, and a redundant secondary brake regulation system, wherein one hydraulic actuator for actuating the vehicle brake is provided per vehicle wheel in a first vehicle axle, which actuator is assigned to both the primary brake regulation system and the secondary brake regulation system, wherein one electromechanical primary actuator per vehicle wheel is assigned to the primary brake regulation system in a second vehicle axle, and one electromechanical secondary actuator is assigned to the secondary brake regulation system.

2. The braking system as claimed in claim 1, wherein the primary brake regulation system has a primary control unit, wherein the primary control unit generates primary positioning signals on the basis of a setpoint deceleration specification generated in a pilot system and/or a setpoint deceleration specification generated on the part of the driver by a brake pedal, using which positioning signals the hydraulic actuators and the electromechanical primary actuators are activatable, wherein the secondary brake regulation system has a secondary control unit, and the secondary control unit generates secondary positioning signals on the basis of a setpoint deceleration specification generated in a pilot system and/or a setpoint deceleration specification generated on the part of the driver by a brake pedal, using which positioning signals the hydraulic actuators and the electromechanical secondary actuators are activatable.

3. The braking system as claimed in claim 1, wherein the two hydraulic actuators are connected to one another via a hydraulic circuit, by which, in the event of failure of one hydraulic actuator, the other, still functional hydraulic actuator takes over the braking and/or steering tasks for both vehicle wheel brakes of the first vehicle axle.

4. The braking system as claimed in claim 1, wherein the brake pedal is a component of a foot pedal simulator unit having at least one pedal sensor, and the foot pedal simulator unit converts the mechanical pedal movement into an electrical foot pedal signal, which is the setpoint deceleration specification generated on the part of the driver.

5. The braking system as claimed in claim 1, further comprising: a primary vehicle electrical system and a redundant secondary vehicle electrical system, which each supply the primary control unit and the secondary control unit with electrical energy independently of one another.

6. The braking system as claimed in claim 1, wherein each vehicle wheel is assigned a primary speed sensor and a secondary speed sensor, which each have a signal connection to the primary control unit and to the secondary control unit.

7. The braking system as claimed in claim 1, wherein the pilot system has a signal connection to the primary control unit via a primary signal line, and the pilot system has a signal connection to the secondary control unit via a secondary signal line independent thereof.

8. The braking system as claimed in claim 1, wherein a connecting signal line is laid between the primary control unit and the secondary control unit, via which items of status information are exchangeable between the control units, and in case of error in the primary brake regulation system, the primary control unit generates an error signal, using which the secondary control unit is activatable via the connecting signal line, so that in place of the primary brake regulation system, the secondary brake regulation system takes over the implementation of the setpoint deceleration specification.

9. The braking system as claimed in claim 1, wherein in normal driving operation, both the primary brake regulation system and also the secondary brake regulation system are in use, so that both brake regulation systems operate in parallel operation.

10. The braking system as claimed in claim 1, wherein at least one of the electromechanical actuators has a blocking function, by which in a parking situation, the actuator blocks the assigned vehicle wheel by brake actuation.

11. The braking system as claimed in claim 2, wherein the two hydraulic actuators are connected to one another via a hydraulic circuit, by which, in the event of failure of one hydraulic actuator, the other, still functional hydraulic actuator takes over the braking and/or steering tasks for both vehicle wheel brakes of the first vehicle axle.

12. The braking system as claimed in claim 2, wherein the brake pedal is a component of a foot pedal simulator unit having at least one pedal sensor, and the foot pedal simulator unit converts the mechanical pedal movement into an electrical foot pedal signal, which is the setpoint deceleration specification generated on the part of the driver.

13. The braking system as claimed in claim 3, wherein the brake pedal is a component of a foot pedal simulator unit having at least one pedal sensor, and the foot pedal simulator unit converts the mechanical pedal movement into an electrical foot pedal signal, which is the setpoint deceleration specification generated on the part of the driver.

14. The braking system as claimed in claim 2, further comprising: a primary vehicle electrical system and a redundant secondary vehicle electrical system, which each supply the primary control unit and the secondary control unit with electrical energy independently of one another.

15. The braking system as claimed in claim 3, further comprising: a primary vehicle electrical system and a redundant secondary vehicle electrical system, which each supply the primary control unit and the secondary control unit with electrical energy independently of one another.

16. The braking system as claimed in claim 4, further comprising: a primary vehicle electrical system and a redundant secondary vehicle electrical system, which each supply the primary control unit and the secondary control unit with electrical energy independently of one another.

17. The braking system as claimed in claim 2, wherein each vehicle wheel is assigned a primary speed sensor and a secondary speed sensor, which each have a signal connection to the primary control unit and to the secondary control unit.

18. The braking system as claimed in claim 3, wherein each vehicle wheel is assigned a primary speed sensor and a secondary speed sensor, which each have a signal connection to the primary control unit and to the secondary control unit.

19. The braking system as claimed in claim 4, wherein each vehicle wheel is assigned a primary speed sensor and a secondary speed sensor, which each have a signal connection to the primary control unit and to the secondary control unit.

20. The braking system as claimed in claim 5, wherein each vehicle wheel is assigned a primary speed sensor and a secondary speed sensor, which each have a signal connection to the primary control unit and to the secondary control unit.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0030] An exemplary embodiment of the invention is described hereinafter on the basis of the FIGURE.

DETAILED DESCRIPTION

[0031] A schematic block circuit diagram of the braking system of a two-track autonomous vehicle having a front axle VA and a rear axle HA is shown in the FIGURE. Accordingly one vehicle wheel brake 1 is assigned to each of the two front wheels VL, VR and each of the two rear wheels HR, HL. Each of the vehicle wheel brakes 1 has a brake caliper 2, which interacts with a brake disk 7 of the vehicle wheel brake 1. A hydraulic actuator 8, 10 is assigned to each of the two vehicle wheel brakes 1 of the front axle VA.

[0032] In contrast, an electromechanical primary actuator 3, that is to say which operates without hydraulics, and an electromechanical secondary actuator 5 is assigned to each rear wheel on the rear axle HA. The primary actuator 3 is a component of a primary brake regulation system BRS1, while the secondary actuator 5 is a component of a secondary brake regulation system BRS2.

[0033] The primary brake regulation system BRS1 is constructed in the FIGURE from a primary control unit 9 and the total of two electromechanical primary actuators 3 on the rear axle HA, which are each assigned to one vehicle wheel brake 1. Moreover, the primary control unit 9 has a signal connection to a primary speed sensor 11 for each vehicle wheel VL, VR, HR, HL. Furthermore, the primary control unit 9 has a signal connection to the two hydraulic actuators 8, 10 of the vehicle front axle VA.

[0034] The redundant secondary brake regulation system BRS2 has structurally equivalent components to the primary brake regulation system BRS1. Accordingly, the secondary brake regulation system BRS2 is constructed from a secondary control unit 13 and the total of two electromechanical secondary actuators 5 on the rear axle HA. The secondary control unit 13 moreover has a signal connection to secondary speed sensors 15, which are provided at each vehicle wheel. Furthermore, the secondary control unit 13 also has a signal connection to the two hydraulic actuators 8, 10 of the vehicle front axle VA.

[0035] Each of the hydraulic actuators 8, 10 can have, for example, an electrically operated hydraulic pump activatable by the control unit 9, 13. This pump is connected on the pressure side via a brake pressure line to a hydraulic cylinder, using which the brake caliper 2 of the vehicle wheel brake 1 can be brought into pressure contact with the brake disk 7 of the vehicle wheel brake 1. To control the brake pressure, a hydraulic control valve can be arranged in the brake pressure line, which is activatable using the respective control unit 9, 13.

[0036] In normal driving operation, primary positioning signals y.sub.1 are generated in the primary control unit 9 on the basis of a setpoint deceleration specification V.sub.P generated in a pilot system 17 (for example, a driver assistance system having ABS and EPS functions) and/or a setpoint deceleration specification V.sub.B generated on the part of the driver by means of a brake pedal 19. With the aid of the primary positioning signals y.sub.1, the respective electromechanical primary actuators 3 of the rear axle HA and the two hydraulic actuators 8, 10 of the front axle VA can be activated to perform diverse braking or steering tasks.

[0037] The primary control unit 9 and the secondary control unit 13 are each supplied with electrical energy independently of one another by a primary vehicle electrical system 31 and a redundant secondary vehicle electrical system 33.

[0038] In the FIGURE, the brake pedal 19 is a component of a foot pedal simulator unit having a pressure sensor 21 and a distance sensor 23. The foot pedal simulator unit converts the pedal movement detected by the two sensors 21, 23 into an electrical foot pedal signal which corresponds to the setpoint deceleration specification V.sub.B generated on the part of the driver.

[0039] In the FIGURE, the pilot system 17 moreover has a signal connection to the primary control unit 9 using a primary signal line 25, while the pilot system 17 has a signal connection to the secondary control unit 13 via a secondary signal line 27 independently thereof. In addition, the two control units 9, 13 are connected to one another by means of a connecting signal line 29. Items of status information can be exchanged between the two control units 9, 13 via the connecting signal line 29.

[0040] In normal driving operation, only the primary brake regulation system BRS1 is used in the illustrated embodiment variant, while the redundant secondary brake regulation system BRS2 is deactivated. If a diagnostic module in the primary control unit 9 detects a case of error in the primary brake regulation system BRS1, an error signal S.sub.F is generated, which is read out by the primary control unit 9 via the connecting signal line 29 in the secondary control unit 13. The secondary brake regulation system BRS2 thereupon takes over the implementation of the setpoint deceleration specifications V.sub.P, V.sub.B.

[0041] Alternatively thereto, both the primary brake regulation system BRS1 and also the secondary brake regulation system BRS2 can already be in use in normal driving operation, so that both brake regulation systems operate in parallel operation.

[0042] In addition, the electromechanical primary and secondary actuators 9, 13 each have a blocking function, by which the respective actuator 3, 5 blocks the assigned vehicle wheel by brake actuation in a parking situation.

LIST OF REFERENCE SIGNS

[0043] 1 vehicle wheel brake [0044] 2 brake caliper [0045] 3, 5 primary and secondary actuators [0046] 7 brake disk [0047] 8 hydraulic actuator [0048] 9 primary control unit [0049] 8 hydraulic actuator [0050] 11 primary speed sensor [0051] 12 hydraulic circuit [0052] 13 secondary control unit [0053] 15 secondary speed sensors [0054] 17 pilot system [0055] 19 brake pedal [0056] 21 pressure sensor [0057] 23 distance sensor [0058] 25 primary signal line [0059] 27 secondary signal line [0060] 29 connecting signal line [0061] 31 primary vehicle electrical system [0062] 33 secondary vehicle electrical system [0063] S.sub.F error signal [0064] V.sub.P, V.sub.B setpoint deceleration specifications [0065] y.sub.1, y.sub.2 positioning signals [0066] BRS1 primary brake regulation system [0067] BRS2 secondary brake regulation system [0068] VA vehicle front axle [0069] HA vehicle rear axle