Electromechanical braking systems and methods for motor vehicles

Abstract

The present invention relates to an electromechanical braking system (1) for a motor vehicle, comprising: four wheel braking devices (2), four primary electric motors (3), four secondary electric motors (4), two controllers (5), and a backup controller (8). A key feature of the braking system (1) according to the invention is that the controllers (5) and / or the backup controller (8) are configured to detect and / or analyze sensor data from sensors (6) associated with the wheel braking devices (2) and / or the motor vehicle. Each wheel braking device (2) is respectively assigned one primary electric motor from the primary electric motors (3) and one secondary electric motor from the secondary electric motors (4) for operating the corresponding wheel braking device (2). Each controller (5) is associated with two primary electric motors from the primary electric motors (3) of the two wheel braking devices (2), and the backup controller (8) is associated with the four secondary electric motors (4) of the wheel braking devices (2) for operating the electric motors (3, 4).

Description

Technical Field

[0001] The present invention relates to an electromechanical braking system for a motor vehicle, the braking system having four wheel braking devices, four primary electric motors, four secondary electric motors, two controllers, and a backup controller.

[0002] Furthermore, the present invention relates to a method for operating such a braking system. Background Technology

[0003] In order to perform automated braking processes, for example, within the framework of autonomous driving of a motor vehicle, the braking system of the motor vehicle must have an actuator that can be controlled independently of the driver operating the brake pedal. Such a braking system is, for example, constructed as an electromechanical braking system and has a wheel brake for each wheel of the motor vehicle. Each of these wheel brakes is operated by an electric motor associated with that wheel brake to brake the motor vehicle. To control the electric motor, the braking system has one or more controllers.

[0004] The law stipulates that braking systems must be constructed in such a way for safety reasons that they can continue to brake the motor vehicle with a predetermined minimum deceleration even in the event of a malfunction, i.e., when one component of the braking system fails. In hydraulic braking systems, a mechanical coupling is typically provided between the brake pedal and the wheel braking devices for emergency maneuvering.

[0005] However, if the braking system is constructed as a purely electromechanical system, especially as a so-called "brake-by-wire" braking system (in which mechanical emergency maneuvering is not possible), then in the event of a failure, braking is usually guaranteed by the following method: the components of the braking system are installed redundantly and / or assume redundant functions for each other.

[0006] Braking systems with redundant components are known from existing technology. For example, publication EP 3 318 458B1 discloses an electric braking device for a motor vehicle with three control units, wherein each control unit controls two braking mechanisms for braking two wheels, and wherein, in the event of a failure of one or two control units, at least one of the other control units operates the corresponding braking mechanism of the failed control unit, thereby enabling continued braking of the motor vehicle. Specifically, two of the control units are configured as diagonal wheel control units, and the third control unit is configured as a front wheel control unit. Alternatively, the control units are configured such that they can operate all four braking mechanisms individually. However, no redundancy is provided for the braking mechanisms themselves, thus reducing the braking power of the motor vehicle when one braking mechanism fails. Summary of the Invention

[0007] The braking system according to the invention comprises: four wheel braking devices, four primary electric motors, four secondary electric motors, two controllers, and a backup controller. The key feature of this braking system is that the controllers and / or the backup controller are configured to detect and / or analyze sensor data associated with sensors belonging to the wheel braking devices and / or the motor vehicle. Each wheel braking device is respectively assigned one primary electric motor and one secondary electric motor for operating the corresponding wheel braking device. Each controller is associated with two of the primary electric motors of two wheel braking devices, and the backup controller is associated with the four secondary electric motors of the wheel braking devices for operating the primary electric motors and / or the secondary electric motors. This achieves advantageous redundancy not only for the operation of the braking devices but also for the operation of the electric motors associated with the wheel braking devices. Each wheel brake in the wheel braking system is thus allocated: a controller in the controller, a backup controller, a primary electric motor in the primary electric motor, and a secondary electric motor in the secondary electric motor, so that even if one or more controllers in the controller and / or one or more electric motors in the electric motor fail, the braking power of the braking system remains fully available. The electric motors are functionally assigned to the corresponding wheel brake, i.e., operatively connected or mechanically coupled to the brake, and spatially assigned to the wheel brake, i.e., arranged at the corresponding wheel brake location. Each secondary electric motor acts as a redundancy for the primary electric motor. When the corresponding primary electric motor fails, only the secondary electric motor is used. It is particularly conceivable that the secondary electric motors are configured such that only the legally required minimum deceleration is achieved during braking, and in this respect, they possess a smaller maximum power and size than the primary electric motors. Thus, despite the redundancy, structural space is advantageously saved. The controller and / or backup controller are functionally assigned to the wheel braking devices, i.e., electrically connected to the wheel braking devices in terms of signaling technology, and are arranged at any location in the vehicle, or spatially assigned to at least one of the wheel braking devices, i.e., particularly at the wheel braking devices. By assigning the controller to each of two wheel braking devices and the backup controller to all four wheel braking devices, only three controllers are needed instead of eight to achieve advantageous redundancy, thereby reducing the complexity and cost of the braking system.The design scheme of the controller for analyzing and / or detecting sensor data advantageously eliminates the need for a separate controller specifically constructed for this purpose or achieves redundancy for such a controller, wherein at least one of the sensors is redundantly installed and / or assigned to two controllers, particularly one controller and a backup controller.

[0008] According to a preferred embodiment of the invention, the sensors are configured as rotor position sensors, speed sensors, airbag sensors, and / or spacing sensors. This sensor design advantageously ensures that the controller can directly detect and / or analyze the relevant sensor data for operating the electric motor. If the electric motor is configured, for example, as an electrically commutated motor, then the precise angular position of its rotor must be detected for operation. If the controller directly detects this via the corresponding rotor position sensor, then particularly advantageous and efficient control of the electric motor is ensured. Wheel speeds are determined by means of speed sensors associated with the wheels of the motor vehicle, and these wheel speeds can be taken into account during braking, for example, to advantageously prevent locking of one wheel. Hazardous situations and / or accident situations can be identified based on sensor data from the airbag sensor and / or spacing sensor, allowing the controller to initiate braking, especially emergency braking, when necessary. Preferably, at least one of the sensors is configured or arranged close to the wheels, particularly as a microphone for noise monitoring. This also advantageously ensures the direct detection and / or analysis of the relevant sensor data.

[0009] According to a preferred embodiment of the invention, the primary and / or secondary electric motors are configured as electrically commutated or brushless electric motors. This design, using electrically commutated electric motors, advantageously ensures efficient operation of the wheel braking system. Preferably, only the primary electric motor is configured as an electrically commutated electric motor, and the secondary electric motor is configured as a DC motor, which advantageously saves structural space. Alternatively, the primary and / or secondary electric motors are configured as three-phase asynchronous motors. This is particularly advantageous because such motors do not require rotor position sensors for detecting the angular position of their rotors, thus allowing for cost-effective construction of the electric motors. Similarly, it is conceivable that a primary motor and a secondary motor are constructed as a common motor, having primary motor windings and secondary motor windings, particularly stator windings. These windings can be controlled independently of each other, and when controlling the primary winding, the motor functions as a primary motor, and when controlling the secondary winding, it functions as a secondary motor. The connection between the motor windings and the controller is similar to the previously described relationship between the motor and the controller. Especially since the primary motor and the secondary motor are each arranged in a common housing having only one rotor, it is advantageous to construct the motor at a low cost.

[0010] According to a preferred embodiment of the invention, the controller is positioned directly at the next wheel brake device, the primary electric motor of which is assigned the controller. This arrangement of the controller advantageously ensures that the length of potentially faulty wiring between the respective primary electric motor and the controller is minimized, thereby improving operational reliability. Alternatively, the controller and / or backup controller are positioned in a protected area of ​​the motor vehicle, where they are subjected to less temperature requirements and environmental influences than near the wheel brake devices. In this protected area, the controller and / or backup controller are less robust and therefore advantageously implemented at a lower cost.

[0011] According to a preferred embodiment of the invention, the wheel braking devices, each assigned to a controller, are arranged at the same axle of the motor vehicle. This arrangement advantageously ensures that even if one controller and the backup controller fail, the remaining controller can still operate the two wheel braking devices at at least one of the two axles. The braking system is designed with parallel redundancy in the axle configuration.

[0012] According to a preferred embodiment of the invention, the wheel braking devices assigned to the controller are respectively assigned to different axles of the motor vehicle and arranged at opposite ends of the axles. This assignment advantageously ensures that each controller operates one of the electric motors on each of the two axles, and therefore, even if one controller and the backup controller fail, one of the wheel braking devices on each of the two axles can still be operated independently. The braking system is designed diagonally redundantly on the axle sides.

[0013] A key feature of the method for operating the braking system according to the invention is that the primary and / or secondary electric motors, controllers, and backup controllers of the braking system are monitored for functionality, and a backup response is triggered when one of the primary electric motors and / or one of the secondary electric motors, one of the controllers, or the backup controller fails. This monitoring of functionality and the triggering of the backup response advantageously ensure that the failure of one of the electric motors, one of the controllers, and / or the backup controller is identified without delay, and that the braking effect of the braking system is maintained.

[0014] According to a preferred embodiment of the invention, a secondary electric motor belonging to the same wheel braking device is operated as a backup response in the event of a failure of one of the primary electric motors. Operating the secondary electric motor advantageously ensures continued operation of the wheel braking device.

[0015] According to a preferred embodiment of the invention, a backup controller is operated as a standby response in the event of a failure of one of the controllers. Operating the backup controller advantageously ensures continued operation of the braking devices for all four wheels.

[0016] According to a preferred embodiment of the invention, an alarm is output as a backup response, particularly on a display device belonging to the driver of the motor vehicle. Outputting an alarm advantageously ensures that the driver is notified of the failure without delay and is able to take appropriate action, particularly to stop driving and / or go to the workshop. Preferably, the alarm is output while performing one of the backup responses described above, wherein the failure of one of the controllers and / or another of the electric motors is compensated for by appropriately operating a backup controller and / or one of the electric motors. If only the failure of one of the secondary electric motors or the backup controller is determined, then in particular, it is not necessary to change the operation, and outputting an alarm is sufficient. Preferably, the alarm is output according to the importance or severity of the failure, for example, by using different color codes. Thus, for example, only a yellow warning light is used to indicate the failure of one of the secondary electric motors or the backup controller, while a red warning light is used to indicate the failure of one of the primary electric motors and / or one of the controllers. Similarly, it can advantageously output different operating instructions to the driver, such as outputting a request to immediately stop driving in the event of a failure of one of the primary electric motors and / or one of the controllers. Attached Figure Description

[0017] Further preferred features and combinations thereof are derived from the foregoing description and the claims. The invention will be explained in more detail below with reference to the accompanying drawings. For this purpose, only the accompanying drawings are shown: The attached diagram shows a schematic of an electromechanical braking system. Detailed Implementation

[0018] An advantageous electromechanical braking system 1 for a motor vehicle (not shown in more detail) is described below with reference to the accompanying drawings. The braking system 1 has exactly four wheel braking devices 2. Each wheel braking device 2 is associated with one of the wheels of the motor vehicle (also not shown). In this embodiment, the braking system 1 is implemented purely electromechanically and therefore does not include hydraulic components or hydraulic circuits for operating the wheel braking devices 2.

[0019] More precisely, braking is achieved by directly manipulating the wheel braking device 2, which is specifically configured as a friction braking device. For this purpose, the braking system 1 has exactly four primary electric motors 3 and exactly four secondary electric motors 4. In this embodiment, the electric motors 3 and 4 are configured as electrically commutated electric motors. Each wheel braking device in the wheel braking device 2 is allocated one primary electric motor from the primary electric motor 3 and one secondary electric motor from the secondary electric motor 4 for respectively manipulating the corresponding wheel braking device 2.

[0020] Furthermore, the braking system 1 has exactly two controllers 5 and exactly one backup controller 8. Each controller 5 is assigned to one of the two primary electric motors 3 of the two primary electric motors of the two wheel brake devices in the wheel brake device 2, and the backup controller 8 is assigned to one of the four secondary electric motors 4 of the wheel brake device 2 for controlling the electric motors 3 and 4. The controllers 5 are each directly arranged at the next wheel brake device in the wheel brake device 2, and the primary electric motor 3 of that wheel brake device is assigned to the controller.

[0021] Each of the secondary electric motors 4 performs redundant functions for the primary electric motors 3 associated with the same wheel braking device 2. In the event of a failure of the corresponding primary electric motor 3, the secondary electric motor 4 associated with the same wheel braking device 2 is activated.

[0022] Similarly, backup controller 8 provides redundancy for controller 5. If one of the controllers in controller 5 fails, backup controller 8 will take over.

[0023] In addition, controller 5 and / or backup controller 8 are configured to detect and / or analyze sensor data associated with the wheel braking device 2 and / or the sensor 6 of the motor vehicle. The sensors include, in particular, a rotor position sensor of one of the electric motors 3 and 4, a wheel speed sensor of one of the wheels of the motor vehicle, an airbag sensor of the motor vehicle, and / or a distance sensor of the motor vehicle.

[0024] Furthermore, as indicated by the double arrows, controller 5 and backup controller 8 are interconnected via a bus system, such as Ethernet, Flexray, or CAN, and connected to another controller 7 of the vehicle. At least one of the other controllers 7 is configured, for example, to further process the sensor data detected or analyzed by controller 5 or backup controller 8.

[0025] In addition, at least one of the other controllers 7 is configured, for example, to monitor the electric motors 3 and 4, as well as controller 5 and backup controller 8, in terms of functionality, and to trigger an appropriate backup response, in particular, to change the operation and / or output fault notification, as described above.

Claims

1. An electromechanical braking system (1) for a motor vehicle, comprising: four wheel braking devices (2), four primary electric motors (3), four secondary electric motors (4), two controllers (5), and a backup controller (8). - in, The controller (5) and / or the backup controller (8) are configured to detect and / or analyze sensor data associated with the wheel braking device (2) and / or the sensors (6) of the motor vehicle. - Each wheel brake device in the wheel brake device (2) is respectively equipped with: one primary electric motor in the primary electric motor (3) and one secondary electric motor in the secondary electric motor (4) for operating the corresponding wheel brake device (2) respectively, and - Each controller in the controller (5) is assigned to two primary electric motors in the two primary electric motors (3) of the two wheel brake devices in the wheel brake device (2), and the backup controller (8) is assigned to four secondary electric motors (4) of the wheel brake device (2) for controlling the primary electric motors (3) and / or the secondary electric motors (4).

2. The braking system according to claim 1, characterized in that, The sensor (6) is configured as a rotor position sensor, a speed sensor, an airbag sensor and / or a spacing sensor.

3. The braking system according to claim 1 or 2, characterized in that, The primary electric motor (3) and / or the secondary electric motor (4) are configured as electrically commutated electric motors.

4. The braking system according to claim 1 or 2, characterized in that, The controller (5) is directly arranged in the wheel braking device (2) at the primary electric motor (3) of the wheel braking device, which is equipped with the controller.

5. The braking system according to claim 1 or 2, characterized in that, The wheel braking devices (2) assigned to the controller (5) are respectively arranged at the same axle of the motor vehicle.

6. The braking system according to claim 1 or 2, characterized in that, The wheel braking devices (2) assigned to the controller (5) are respectively assigned to different axles of the motor vehicle and are arranged at opposite ends of these axles.

7. A method for operating an electromechanical braking system (1) according to any one of claims 1 to 6, characterized in that, The primary electric motor (3) and / or the secondary electric motor (4), the controller (5) and the backup controller (8) of the braking system (1) are monitored for functionality, and a backup response is triggered when one of the primary electric motors (3) and / or one of the secondary electric motors (4), one of the controllers (5) or the backup controller (8) fails.

8. The method according to claim 7, characterized in that, When one of the primary electric motors (3) fails, the secondary electric motor (4) belonging to the same wheel braking device (2) is operated as a backup response.

9. The method according to claim 7 or 8, characterized in that, When one of the controllers (5) fails, the backup controller (8) is operated as a backup response.

10. The method according to claim 7 or 8, characterized in that, Output alarms as a backup response.

11. The method according to claim 10, characterized in that, As a backup response, an alarm is output on the display device of the driver associated with the motor vehicle.

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