Method for operating a brake system of a vehicle and brake system

Abstract

The invention relates to a method for operating a brake system (102) of a vehicle (104), wherein the brake system (102) has an electromechanical brake (108) with its own local controller (110) for a wheel (106) of a brake of the vehicle (104), wherein the local controller (110) has at least one acceleration sensor, which detects a local acceleration (202) at the wheel (106), wherein the local controller (110) controls a brake intervention at the wheel (106) by using the local acceleration (202) and a rotational speed (204) of the wheel in order to adjust a driving dynamics of the wheel (106).

Description

Technical Field

[0001] This invention relates to a method for a braking system for operating a vehicle, a corresponding braking system, and a corresponding computer program product. Background Technology

[0002] The vehicle's electromechanical braking system has a central controller. This controller is located in the center of the vehicle and controls the individual electromechanical brakes on the vehicle's brake wheels via data signals. The data signals are converted into power signals by local controllers on the brakes, which then control the electric drive units of the brakes.

[0003] The central controller is equipped with inertial sensors, which use the signals to adjust the vehicle's driving dynamics by intervening in braking at each wheel. When adjusting longitudinal dynamics, braking intervention minimizes wheel slippage. When adjusting lateral dynamics, braking intervention generates a yaw moment to keep the vehicle traveling in the direction specified by the steering system.

[0004] If the controller malfunctions and / or fails to transmit data signals to the brakes, driving dynamics cannot be adjusted, or can only be adjusted to a limited extent. Summary of the Invention

[0005] Against this backdrop, the present invention proposes a method for a braking system for operating a vehicle, a corresponding braking system, and a corresponding computer program product, according to the independent claims. Advantageous extensions and modifications of the present invention can be derived from the specification and are described in the dependent claims.

[0006] Advantages of the present invention

[0007] The proposed solution creates a backup layer for calculating and / or manipulating braking intervention to regulate driving dynamics in case of failure. Here, a controller mounted on the brakes calculates and manipulates braking intervention for each wheel. To this end, the controller analyzes and evaluates locally available sensor information and derives the parameters of the braking intervention accordingly.

[0008] The method presented here can improve vehicle safety and availability. Even if a failure occurs during central calculation and / or control of braking intervention, the local controller can independently calculate and control braking intervention.

[0009] A method is proposed for a braking system for operating a vehicle, wherein the braking system has an electromechanical brake with its own local controller for each braked wheel of the vehicle, wherein the local controller has at least one acceleration sensor that detects local acceleration at the wheel, and wherein the local controller manipulates braking intervention at the wheel by using local acceleration and wheel rotation speed to adjust the wheel's driving dynamics.

[0010] The concept of embodiments of the present invention can be understood in particular based on the following concepts and understandings.

[0011] The braking system may include multiple electromechanical brakes, which are controlled by a central controller. Each electromechanical brake may have its own local controller. The central controller is connected to the local controllers via data lines. During operation, the central controller sends braking requests to the local controllers via data lines. The local controllers convert these requests into drive signals to drive the corresponding brake's drive motor.

[0012] In addition to the power electronics used to provide drive signals, the local controller also contains at least one processor for processing information. Determined information can be read via data lines. Other information can be detected locally by the local controller. In particular, acceleration can be detected locally. Acceleration can be detected by an accelerometer. The accelerometer can be mechanically coupled to the brake. The accelerometer can detect acceleration on a single axis or multiple axes and map it to an electrical signal. This signal can be referred to as an acceleration signal.

[0013] The rotational speed of the wheel can be detected by a speed sensor on the wheel bearing and read via a data cable.

[0014] The processor is configured to analyze and evaluate acceleration when needed and, alternatively or supplementally, analyze and evaluate rotational speed and, based on this, independently request braking intervention.

[0015] The local controller can make local adjustments in response to faults in the central controller of the braking system. Therefore, the local controller can serve as a backup for the central controller. Consequently, the central controller can be provided with less complexity and at a lower cost.

[0016] The local controller can respond locally to communication interference with the central controller. One or more data lines between the central and local controllers may be damaged. This could result in a data line interruption or simply a loss of the specified data throughput. In such cases, the local controller can take over and adjust the driving dynamics.

[0017] The local controller can make local adjustments in response to takeover commands from the central controller. For example, the central controller can identify potential damage through self-testing. The local controller can then take preventative adjustments to ensure the safe operation of the braking system.

[0018] The local controller can specifically adjust the longitudinal dynamics of the wheels locally. Adjusting the longitudinal dynamics prevents loss of traction during braking or acceleration. Longitudinal adjustment can be referred to as anti-lock braking (ABS) adjustment and anti-slip adjustment. To adjust the longitudinal dynamics, all relevant measurements can be taken locally.

[0019] The local controller can also locally adjust the vehicle's lateral dynamics using the vehicle's rotational rate. Lateral dynamics adjustment generates yaw moments in the vehicle through active braking intervention at each wheel, which, for example, counteract vehicle slippage or swaying. Lateral adjustment may be referred to as electronic stability program or straight-line assist. The rotational rate can be detected via a local rotational rate sensor. Alternatively, the rotational rate can also be read via a data cable. The rotational rate can also be provided by a controller other than the central controller.

[0020] Lateral dynamics can also be locally adjusted by establishing an explicit correspondence between the local controller and the vehicle's position. This explicit correspondence defines the location of each of the vehicle's individually braked wheels. For example, the explicit correspondence could include the distance from the vehicle's structural center of gravity. This distance, for instance, corresponds to the lever arm of the braking force generated by braking intervention.

[0021] The driving dynamics of all wheels can be adjusted via their respective local controllers. In the event of a communication failure in the central controller or with one of the local controllers, driving dynamic adjustment can be completely transferred to the local controller. In particular, driving dynamic adjustment in the relevant braking circuit can be completely transferred to the local controller of the braking circuit. Thus, a clear communication structure can be maintained even in the event of a failure.

[0022] The method is preferably implemented by a computer and can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, such as in a controller.

[0023] The proposed solution also proposes a braking system for a vehicle, wherein the braking system is designed to execute, manipulate, or implement the steps of variations of the proposed method in a corresponding local controller.

[0024] The local controller can be an electrical device having at least one computing unit for processing signals or data, at least one storage unit for storing signals or data, and at least one interface and / or communication interface for reading or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a so-called system ASIC, or a microcontroller for processing sensor signals and outputting data signals based on the sensor signals. The storage unit can be flash memory, EPROM, or magnetic storage. The interface can be designed as a sensor interface for reading sensor signals from a sensor, and / or as an actuator interface for outputting data signals and / or control signals to an actuator. The communication interface can be designed to read or output data wirelessly and / or via a wired connection. The interface can also be a software module, which may coexist with other software modules on a microcontroller, for example.

[0025] It is also advantageous to have a computer program product or computer program with program code, which can be stored on a machine-readable carrier or storage medium, such as semiconductor memory, hard disk memory or optical memory, and can be used to perform, implement and / or manipulate the steps of the method described in the above embodiments, especially when the program product or program is running on a computer or device.

[0026] It should be noted that some possible features and advantages of the invention have been described herein with reference to different embodiments. Those skilled in the art will recognize that the features of the controller and method can be combined, modified, or replaced in a suitable manner to obtain other embodiments of the invention. Attached Figure Description

[0027] Embodiments of the present invention are described below with reference to the accompanying drawings, which should not be construed as limiting the invention.

[0028] Figure 1 A schematic diagram illustrating the central driving dynamic adjustment of a braking system according to one embodiment is shown;

[0029] Figure 2 A schematic diagram illustrating the local driving dynamics adjustment of a braking system according to one embodiment is shown.

[0030] These accompanying drawings are schematic only and are not drawn to scale. The same reference numerals indicate the same or functionally equivalent features. Detailed Implementation

[0031] Figure 1A schematic diagram of a central driving dynamics adjustment 100 for a braking system 102 according to one embodiment is shown. The braking system 102 is installed in a vehicle 104 having four wheels 106. Each wheel 106 is braked by an electromechanical brake 108. Each brake 108 is controlled by a local controller 110. The local controller 110 is controlled by a central controller 112. The brakes 108 are divided into two braking circuits. Each braking circuit has its own power supply, which provides electrical power to the local controller 110 of the corresponding braking circuit.

[0032] Under the indicated adjustment conditions, driving dynamic adjustment 100 is performed in the central controller 112.

[0033] Figure 2 A schematic diagram of local driving dynamics adjustment 100 of a braking system 102 according to one embodiment is shown. The braking system 102 herein substantially corresponds to... Figure 1 The braking system in the middle. Conversely, the central controller 112 has a fault 200 here. Due to fault 200, central driving dynamics adjustment is limited or impossible. Therefore, driving dynamics adjustment 100 is performed in the local controller 110. For this purpose, the local controller 110 uses the acceleration 202 detected in the local controller 110 and the rotational speed 204 of the wheel 106 braked by the connected electromechanical brake 108, respectively.

[0034] In one embodiment, only one braking circuit is affected by fault 200. Then, driving dynamics adjustment 100 is transferred only to the local controller 110 of the relevant braking circuit.

[0035] In an alternative embodiment, even if fault 200 affects only one brake 108, driving dynamics adjustment 100 is completely transferred to the local controller 110.

[0036] In one embodiment, the driving dynamics adjustment 100 is limited to longitudinal dynamics adjustment. Therefore, the driving dynamics adjustment 100 can only ensure ABS and ASR functions.

[0037] In one embodiment, the local controller 110 additionally uses the rotational rate 206 of the vehicle 104. If present, the rotational rate 206 can be measured by a local rotational rate sensor of the local controller 110. Alternatively, the rotational rate 206 can be provided, vehicle-wide, via a communication bus by the vehicle's inertial sensor unit. The local controller can also provide ESP and SLC functionality using the rotational rate 206.

[0038] Even if communication interference 208 occurs between the central controller 112 and the local controller 110, the local controller 100 can still take over the driving dynamics adjustment 100. Similarly, the central controller 112 can output a takeover command 210 for testing or as a precaution, and the local controller 110 will take over the driving dynamics adjustment 100 in response to the takeover command 210.

[0039] The possible configurations of the present invention are summarized below with slight adjustments to the wording.

[0040] It is proposed that the acceleration sensor in the EMB serves as a backup layer for the vehicle's dynamic control.

[0041] Traditionally, hydraulic braking systems are used. In this system, the driver operates the brakes mechanically. In the future, electromechanical brakes (EMBs) may become increasingly widespread and replace hydraulic braking systems. In this system, an electric motor is powered, the generated torque is converted into translational motion by the transmission, and calipers with brake pads decelerate the vehicle through friction.

[0042] Furthermore, EMB actuators can also be implemented with sensing devices such as current sensors, EMB position sensors, and / or wheel speed sensors. This can be referred to as a "smart actuator." In particular, acceleration sensors (such as MEMS) can be used within the ECU at a lower cost to measure acceleration (x, y, and / or z directions), vibration, or sound.

[0043] EMB actuators can be installed on each wheel of the vehicle, thus forming a system. One possible architecture / topology may include a central controller, a communication bus, and EMB actuators.

[0044] In the traditional H-circuit topology of the braking system, the central controller controls the power distribution and manages the EMB actuator.

[0045] The possible functional allocation among the central controllers can be illustrated as follows: the central controller takes over the adjustment of driving dynamics, while the intelligent actuators at the wheels only execute braking commands.

[0046] In the proposed solution, if the central controller malfunctions, the failure or degradation of the driving dynamics adjustment (e.g., ABS (anti-lock braking system)) can be prevented or minimized.

[0047] The method proposed here allows driving dynamics functions to continue operating even under known fault conditions, resulting in more robust driving dynamics adjustments and improved overall vehicle safety.

[0048] In the proposed solution, when the central controller, which normally performs adjustments, fails, a backup adjustment for vehicle dynamics is executed. Here, driving dynamic adjustments are redistributed so that the central unit no longer performs adjustments; instead, the intelligent EMB handles the adjustments locally.

[0049] Causes or malfunctions requiring discrete adjustments to vehicle functions can include, for example, degradation of the communication bus between the central controller and the EMB actuator. This degradation might be due to, for example, reduced bandwidth, loss of real-time capability, or the need to use a inferior COM bus due to a damaged main COM bus. A cause could also be degradation of the central controller, preventing the execution of driving dynamics adjustments. This degradation could be caused, for example, by RAM or flash memory (partial) damage, reduced power supply, or continuous reception of interrupt signals from interrupt programs. A cause could also be damage to a dedicated driving dynamics controller. This could, for example, be caused by a damaged component in the controller.

[0050] In particular, ABS based on wheel speed and / or acceleration sensors (x and / or z directions), ASR based on wheel speed and / or acceleration sensors (x and / or z directions), ESP based on wheel speed and / or acceleration sensors (x, y and / or z directions) and yaw rate, and / or SLC (straight lane control) based on wheel speed and / or acceleration sensors (y direction) and yaw rate.

[0051] In particular, discrete allocation can lead to functional degradation.

[0052] In particular, the central controller can still provide sensor values ​​such as yaw rate, driver input (steering, braking, acceleration), or other wheel speeds (but cannot perform adjustments on its own). This sensor data can then be used by the intelligent EMB to adjust its own driving dynamics.

[0053] At least, the driving dynamics adjustment program is implemented on the EMB. In particular, the same driving dynamics adjustment program is implemented on all EMBs, but configured via an ID. This ID can be provided, for example, during initial vehicle use, after maintenance, after each vehicle start, or when the central adjustment of the EMB malfunctions. Thus, the "correct" EMB executes the adjustment function, such as applying it to the inside rear wheel in case of understeer. Here, the EMB actuator knows it is the left rear wheel brake through its ID and knows it is on the inside of the curve by measuring a_y.

[0054] In particular, all EMB actuators can enter discrete regulation mode simultaneously (although, for example, only one COM bus degrades), or only the actuator with the degraded COM bus can enter that mode.

[0055] In particular, the received / measured sensor data can be provided to other areas, such as suspension, drive, steering or other braking actuators.

[0056] In one particular implementation, the data is not only forwarded, but the EMB even actively regulates it.

[0057] In particular, controllers share their control signals with each other by communicating directly or through a router (e.g., a central controller), especially within the same braking circuit.

[0058] Finally, it should be noted that terms such as "having" and "comprising" do not exclude other elements or steps, and terms such as "a" do not exclude multiple elements. Reference numerals in the claims should not be considered limiting.

Claims

1. A method for operating a braking system (102) for a vehicle (104), wherein the braking system (102) has an electromechanical brake (108) for each braked wheel (106) of the vehicle (104) with its own local controller (110), wherein the local controller (110) has at least one acceleration sensor that detects a local acceleration (202) at the wheel (106), wherein the local controller (110) controls braking intervention at the wheel (106) by using the local acceleration (202) and the rotational speed (204) of the wheel (106) to regulate the driving dynamics of the wheel (106).

2. The method according to claim 1, wherein the local controller (110) performs local adjustment in response to a fault (200) in the central controller (112) of the braking system (102).

3. The method according to any one of the preceding claims, wherein the local controller (110) locally adjusts in response to communication interference (208) to the central controller (112) of the braking system (102).

4. The method according to any one of the preceding claims, wherein the local controller (110) performs local regulation in response to a takeover command (210) from the central controller (112) of the braking system (102).

5. The method according to any one of the preceding claims, wherein the local controller (110) locally adjusts the longitudinal dynamics of the wheel (106).

6. The method according to any one of the preceding claims, wherein the local controller (110) further performs local control of the lateral dynamics of the vehicle (104) by using the rotational rate (206) of the vehicle (104).

7. The method of claim 6, wherein the lateral dynamics are further locally controlled by using an explicit correspondence between the local controller (110) and the position in the vehicle (104).

8. The method according to any one of the preceding claims, wherein the driving dynamics of all wheels (106) are adjusted on the corresponding local controller (110).

9. A braking system (102) wherein the braking system (102) is configured to perform, implement and / or manipulate the method according to any one of the preceding claims in a corresponding device.

10. A computer program product configured to, when executed, direct a processor to perform, implement, and / or manipulate the method according to any one of claims 1 to 9.

11. A machine-readable storage medium on which a computer program product according to claim 10 is stored.

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