Method for operating brake system and brake system

Abstract

To provide a method for operating a brake system in a vehicle.SOLUTION: At one step, first calibration data is transmitted from a first sensor to a first brake product arranged on a brake pedal of a vehicle, and / or second calibration data is transmitted from a second sensor to a second brake product arranged on the brake pedal of the vehicle. The first and the second sensor data are generated by first and second sensors as a user operates the brake pedal. The first and the second sensor data are transmitted to the first brake product and / or second brake product. When it is confirmed that the first brake product and the second brake product exist in the vehicle, the brake system is operated in the first operating state. When it is confirmed that only the first brake product or only the second brake product exists in the vehicle, the brake system is operated in the second operating state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for operating a brake system and to a brake system. [Background technology]

[0002] Modern vehicles with electronic brake pedals ("e-pedals" or brake-by-wire) typically have redundant brake systems with at least two brake products. For example, brake systems are known that include a BWA ("By-Wire Actuation") as a first brake product and an ESP ("Electronic Stability Program") as a second brake product. A brake command can be input by the vehicle driver or user by operating the brake pedal. A redundant sensor in the brake pedal generates a corresponding signal, which is transmitted via electrical lines to the first and second brake products. The brake products then perform pressure buildup in the actual brakes to achieve the desired braking.

[0003] In addition to the actual sensor data representing the braking command, the sensor in the brake pedal also transmits calibration data that the braking products use to accurately interpret the braking command. While the sensor data of at least two sensors is transmitted redundantly to both braking products, each braking product receives the calibration data of only one sensor. The calibration data of each of the other braking products is exchanged between the braking products via an existing bus system (e.g., CAN bus). For normal vehicle operation, this must ensure that the calibration data can be reliably exchanged between the individual braking products. This leads to dependencies between the braking products and the need for bus communication between the braking products.

[0004] During vehicle manufacture or, for example, during vehicle maintenance, however, it is not always possible to guarantee that both brake products are present or active at the same time.

[0005] DE 10 2004 013 143 A1 shows a method for calibrating a pedal module of a motor vehicle, the pedals of which are movable under the action of a force.

[0006] US Patent No. 6,299,649 discloses a target vehicle following control system that monitors the distance relative to the target vehicle and the speed of the host vehicle.

[0007] Patent Document 3 relates to a method for calibrating a signal generator device of a haptic accelerator pedal module for an automobile and a device for implementing this method.

[0008] US Pat. No. 5,629,493 shows an adjustable accelerator pedal assembly. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] German Patent Application Publication No. 102004009846 [Patent Document 2] German Patent Application Publication No. 102010006087 [Patent Document 3] German Patent Invention No. 102014224234 [Patent Document 4] European Patent No. 3962763 Summary of the Invention

[0010] The object of the present invention is to enable operation of a brake system even when only one brake product is present or active in the vehicle. This may enable, for example, testing of individual brake products during vehicle production or maintenance. Furthermore, (semi-)autonomous travel of a vehicle between individual assembly locations, for example in a factory during production, may be possible even when only one brake product is installed or active.

[0011] According to a first aspect of the invention, there is provided a method for operating a brake system in a vehicle as set forth in claim 1. According to a second aspect of the invention, there is provided a brake system for a vehicle as set forth in claim 11. Further aspects of the invention are the subject of the dependent claims, the drawings and the description of the examples.

[0012] The brake pedal of the braking system according to the invention does not necessarily have to be a pedal operated by the foot, but may also be a lever operated by the hand, etc. In the sense of the invention, the brake pedal is a means for inputting a brake command representing the desired braking action, which may be known, for example, via pressure and / or pedal position.

[0013] The brake pedal has at least two sensors that detect the brake command input by the user. By providing at least two sensors, the brake command can be detected redundantly. This ensures the reliability of the system and thus the safety required for driving on public roads.

[0014] Each sensor may transmit calibration data to the brake product. The calibration data is used to interpret the sensor data generated by the sensor when the brake pedal is operated. The calibration data may include static (unchanging) calibration data and dynamic (variable) calibration data. The static calibration data typically depends on the sensor used and must be transmitted at least once, at the initial start-up of the brake product. The dynamic calibration data is preferably transmitted periodically, for example, daily, hourly, minutely, secondly, or multiple times per second. The dynamic calibration data may depend, for example, on the temperature and / or air humidity and / or the brake mileage. The calibration data may be present, in particular, as characteristic lines or characteristic maps. Using the calibration data, it can be ensured that the brakes operate in response to the brake command as desired and expected by the user.

[0015] When the user operates the brake pedal, the sensors each generate sensor data that represent, in particular, the pressure on the brake pedal and / or the displacement of the brake pedal, and correspondingly, the sensors may each comprise at least one pressure sensor and / or at least one stroke sensor.

[0016] The transmission of the first and second sensor data to the first and / or second brake product is preferably performed via separate and therefore redundant communication lines and purely electrically or electronically, thereby ensuring a reliable and safe data transmission that does not require mechanical components for transmitting the brake command.

[0017] The present invention determines whether a first and / or second brake product is present in a vehicle. A brake product is understood here to mean, for example, an actuator with a control device that interprets a brake command and triggers or controls the generation of a corresponding brake pressure in the vehicle's brakes. Brake products include, in particular, BWA or ESP. A safe and redundant brake-by-wire brake system can thus be realized.

[0018] If the presence of the first brake product and the second brake product in the vehicle is determined, the brake system is operated in a first operating state. The first operating state is a normal state in which the vehicle may be moved in road traffic. The presence of the first and second brake products may be determined, for example, via a CAN bus. Only when both brake products are present and ready for use may the vehicle be operated in the normal first operating state.

[0019] If it is determined that only the first brake product or only the second brake product is present in the vehicle, the brake system is operated in a second operating state, which may be referred to as a maintenance state, an emergency mode, or a production state. In this state, only one of the brake products is installed in the vehicle, is active, and is not ready for operation. As a result, in this state, there is no redundant brake system. For test purposes, for emergency operation under limited boundary conditions, or for traveling between assembly locations in manufacturing, for example, however, operation (e.g., for a short time) of a vehicle with only one brake product may also be permitted.

[0020] In particular, during vehicle manufacturing and assembly, only a first brake product may be initially installed in the vehicle. The brake system is then placed in a second operating state according to the present invention so that this brake product can be tested before the installation or activation of a second brake product. In this second operating state, the first brake product may also be tested without calibration data for the second sensor. For this purpose, predetermined calibration data for the second sensor may be stored on the first brake product, for example, in a memory device of the control device of the first brake product. Furthermore, it may be possible to interpret a brake command from the brake pedal solely based on the first sensor data and the corresponding first calibration data.

[0021] According to a preferred embodiment, the first or second sensor may comprise a pressure sensor or a stroke sensor. It is particularly preferred that the first or second sensor comprise both a pressure sensor and a stroke sensor. This allows the brake command to be generated on the basis of at least two independent sensors and measurement methods. The brake pedal may therefore be configured, in particular, as a pressure plate or a movable brake pedal, so that only the pressure, only the stroke, or both the pressure and the stroke are detected by the corresponding sensors.

[0022] The first brake product may preferably have an Electronic Stability Program, ESP, and the second brake product may preferably have a by-wire actuator, BWA. According to an alternative configuration, the first brake product may have a BWA and the second brake product may have an ESP.

[0023] The method according to any one of the preceding claims further comprising: In the first operating state, exchanging the first and second calibration data between the first brake product and the second brake product via a bus system; operating a first brake product and a second brake product in response to the first and second calibration data and the sensor data, respectively; Includes.

[0024] Preferably, the first brake product may be operated in a second operating state according to the first calibration data and the sensor data. More preferably, the first brake product may additionally be operated according to pre-stored second calibration data. This eliminates the need for communication with the second brake product to obtain and exchange the second calibration data in the second operating state. In this state, the vehicle's brake system can be operated solely by the first brake product. In other words, the first brake product can independently generate and control the brake pressure for braking the vehicle. This is advantageous, for example, when testing the first brake product during vehicle manufacturing or maintenance.

[0025] Conversely, the second brake product may be operated according to the second calibration data and the sensor data without knowing the first calibration data. More preferably, the second brake product may additionally be operated according to the previously stored first calibration data. This eliminates the need for communication with the first brake product to learn and exchange the first calibration data during the second operating state. In this state, the vehicle's brake system can be operated solely by the second brake product. In other words, the second brake product can independently generate and control the brake pressure for braking the vehicle. This is advantageous, for example, when testing the second brake product during vehicle manufacturing or maintenance.

[0026] The first and second calibration data may include, for example, static calibration data, in particular calibration data representing unchanging hardware characteristics of the sensor, and / or dynamic calibration data, in particular calibration data representing variable characteristics of the sensor.

[0027] Preferably, in the second operating condition, a warning notification may be output to the user indicating to the user that the brake system is in the second operating condition. The warning notification may be displayed, for example, on an instrument cluster or an infotainment system. The warning notification may include auditory and / or visual information.

[0028] More preferably, the operation of the vehicle can be limited in the second operating state. For example, the maximum speed of the vehicle in the second operating state can be limited to a maximum value of, for example, 10 to 50 km / h, in particular 40 km / h, 30 km / h, or 20 km / h. Furthermore, passenger occupancy can be prohibited in the second operating state by detecting whether a person is present in the passenger seat. This measure contributes to safety, since there can be no redundant braking system in the second operating state.

[0029] If, in the second operating state, it is determined that the first brake product can communicate with the second brake product via the bus system, the brake system can be transitioned to the first operating state. In other words, the bus system determines that two brake products are now again present in the vehicle and ready to operate. This allows the factory or production mode to be exited again. The vehicle can again be operated under normal operating conditions.

[0030] Preferably, a user can input a control command in a first operating state to transition the brake system from the first operating state to a second operating state, and the brake system can then be operated in the second operating state, which can be done, for example, during maintenance of the brake system or during manufacture of the vehicle.

[0031] A braking system for a vehicle according to the present invention includes a brake pedal through which a user inputs a braking command, a first sensor disposed on the brake pedal and configured to generate first sensor data in response to the braking command, a second sensor disposed on the brake pedal and configured to generate second sensor data in response to the braking command, and a first brake product and / or a second brake product communicatively connected to the first and second sensors, respectively, configured to perform a method according to the present invention.

[0032] The invention will be explained in more detail below on the basis of examples shown in schematic drawings. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a schematic plan view of a brake system according to an embodiment of the present invention; [Figure 2] FIG. 2 illustrates an exemplary flow diagram of a method of operating a brake system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The accompanying drawings are intended to provide a further understanding of embodiments of the present invention. The drawings illustrate embodiments and, together with the description, serve to explain the principles and concepts of the present invention. Other embodiments and many of the stated advantages will become apparent from a consideration of the drawings. Elements of the drawings are not necessarily to scale relative to each other.

[0035] In the figures of the drawings, elements, features and components that are the same, functionally identical or have the same effect are respectively designated by the same reference numerals unless otherwise configured differently.

[0036] 1 shows a schematic plan view of a brake system 10 according to one embodiment of the present invention. The brake system 10 comprises a brake pedal 3, on which a first sensor 4 and a further sensor 5 are arranged. The sensors 4 and 5 are communicatively connected via suitable lines to a first brake product 1, here for example a BWA, and to a second brake product 2, here for example an ESP. The first and second brake products 1 and 2 are communicatively connected to each other via a CAN bus system 6 within the vehicle.

[0037] The first sensor 4 is, for example, a pressure sensor. The second sensor 5 is, for example, a stroke sensor. When the brake pedal 3 is operated, the two sensors 4, 5 generate first and second sensor data, respectively, which represent the pressure on the brake pedal 3 or the stroke of the brake pedal 3. The first and second sensor data are transmitted to the two brake products 1, 2.

[0038] Additionally, the sensors 4 and 5 transmit first and second calibration data, respectively, which include static calibration data and dynamic calibration data. The first sensor 4 transmits its first calibration data only to the first brake product 1. The second sensor 5 transmits its second calibration data only to the second brake product 2. This reduces the bandwidth required for communication between the sensors 4 and 5 and the brake products 1 and 2.

[0039] Via the CAN bus system 6, the first brake product 1 and the second brake product 2 exchange calibration data received from the sensors 4, 5, so that both brake products 1, 2 have the first and second calibration data, respectively. Only when both brake products 1, 2 have the first and second calibration data at hand can the brake system 10 create the redundancy required for safety. Accordingly, only in this case can the vehicle be operated in a normal operating state, which will be referred to hereinafter as the first operating state.

[0040] According to the present invention, the brake system 10 can also be operated in a second operating state, which may also be referred to as a factory mode or test mode. This second operating state can be used, for example, during vehicle production or maintenance. In the second operating state, only one of the two brake products 1, 2 is installed in the vehicle or is not ready for operation. Correspondingly, the exchange of calibration data via the CAN bus system 6 cannot be performed.

[0041] In the first case, when the vehicle is manufactured, for example, only the first brake product 1, the BWA, is initially installed in the vehicle. After the BWA is installed, it is desirable to test its function before the ESP (second brake product 2) is installed. For this purpose, the brake system 10 can be switched to the second operating state by a control command. Alternatively, the control device of the brake system 10 can automatically recognize that only the first brake product 1 is installed and automatically assume the second operating state.

[0042] Since communication with the second brake product 2 is not possible, the first brake product 1 only has the calibration data of the first sensor 4. The sensor data of the second sensor 5 therefore cannot be interpreted based on the latest calibration data. Sensor redundancy therefore does not exist. Normally, the vehicle control would not allow driving. For example, to nevertheless allow testing of the first brake system 1 or driving to the next assembly location in production, the second driving mode is used, which allows driving at a limited speed, for example (e.g., creeping speed or a maximum of 10-20 km / h).

[0043] To also use the second sensor data, the first brake product 1 may use pre-stored reference calibration data (static calibration data) for the second sensor 5. The reference calibration data may be particularly hardware-dependent. Only the dynamic, i.e. variable, calibration data may be discarded in this case.

[0044] As soon as the brake system 10 recognizes that a second brake product 2 is also installed, for example because communication between the brake products 1 and 2 is possible via a CAN bus system 6, a switchover to the first operating state can be performed automatically.

[0045] 2 shows an exemplary flow diagram of the method according to the invention for operating a brake system 10 according to one embodiment. The method will be described below for the above-mentioned case where only the first brake product 1 is installed in the vehicle.

[0046] In a first step S1, first calibration data is transmitted from a first sensor 4 arranged on the brake pedal 3 of the vehicle to a first brake product 1. Transmission of second calibration data from a second sensor 5 arranged on the brake pedal 3 to a second brake product 2 is not performed because the second brake product 2 has not been installed. This may be the case, for example, during production or maintenance of the vehicle.

[0047] The brake pedal 3 is then operated by the user in step S2. In particular, the user presses the brake pedal 3 with his / her foot, which results in pressure being exerted on the brake pedal 3 and a displacement of the brake pedal 3. The pressure and travel of the brake pedal 3 are determined by the sensors 4, 5. Correspondingly, in a second step S2, first and second sensor data are generated by the first and second sensors 4, 5 in response to the operation of the brake pedal 3 by the user.

[0048] The generated first and second sensor data are transmitted to the first brake product 1 in step S3.

[0049] In step S4, which may be performed before any other steps, for example, the controller of the brake system 10 determines whether the first brake product 1 and the second brake product 2 are present in the vehicle. This step may be performed by the controller of each of the brake products 1, 2, for example, by determining whether they are able to communicate with each other brake product 1, 2 via the CAN bus system 6 or whether calibration data is received from each other brake product 1, 2.

[0050] In this example, the first brake product 1 determines in step S4 that no second calibration data is received from the second brake product 2. The second brake product 2 is either not installed, not ready for operation, or some fault exists in the CAN bus system 6. The brake system 10 is then operated in a second operating state (step S6).

[0051] Once the second brake product 2 is installed, or once communication between the brake products 1 and 2 is established via the CAN bus system 6 and calibration data is exchanged between the brake products 1 and 2, it is recognized in S4 that operation in the first operating state (S5) is possible.

[0052] The method described above may be performed periodically to monitor the status of the brake system 10 and ensure that the brake system 10 is ready for operation. This may ensure safe operation of the vehicle. Furthermore, it may automatically recognize when, for example, maintenance is being performed on the vehicle and it is desirable to allow only limited operation of the vehicle. The second operating state may also be enabled, particularly in the event of a vehicle breakdown, to allow travel at reduced speed to a safe parking location.

[0053] In the present invention, features are designated as "first" and "second." These designations are used solely to clearly distinguish between individual features. In particular, no spatial or functional priority is to be derived from these designations.

[0054] Whenever the term "or" appears in this application in connection with a list of alternatives, it should be understood that this refers to each listed alternative alone or, where meaningful, to a combination of more than one or all of the listed alternatives. [Explanation of symbols]

[0055] 1. The No. 1 brake product 2. Second brake products 3. Brake pedal 4. First Sensor 5 Another sensor, second sensor 6 CAN bus system 10. Brake System S1 Step S2 Step S3 Step S4 Step S5 Step S6 Step

Claims

1. A method of operating a brake system (10) in a vehicle, comprising: a step (S1) of transmitting first calibration data from a first sensor (4) arranged on a brake pedal (3) of the vehicle to a first brake product (1) and / or a step of transmitting second calibration data from a second sensor (5) arranged on the brake pedal (3) of the vehicle to a second brake product (2); a step (S2) of generating first and second sensor data by the first and second sensors (4, 5) in response to an operation of the brake pedal (3) by a user; (S3) transmitting the first and second sensor data to the first brake product (1) and / or the second brake product (2); a step (S4) of checking whether the first brake product (1) and / or the second brake product (2) are present in the vehicle; operating the braking system (10) in a first operating state (S5) if it is determined that the first brake product (1) and the second brake product (2) are present in the vehicle; or a step (S6) of operating the brake system (10) in a second operating state when it is determined that only the first brake product (1) or only the second brake product (2) is present in the vehicle; Including, A method for operating a brake system in a vehicle.

2. the first sensor (4) comprises a pressure sensor and / or a stroke sensor; and / or The second sensor (5) comprises a pressure sensor and / or a stroke sensor. The method of claim 1.

3. said first brake product (1) has an Electronic Stability Program, ESP, and / or The second brake product (2) has a by-wire actuator, BWA. The method according to claim 1 or 2.

4. moreover, In the first operating state, exchanging the first and second calibration data between the first brake product (1) and the second brake product (2) via a bus system (6); operating the first brake product (1) and the second brake product (2) in response to the first and second calibration data and the sensor data, respectively; Including, 4. The method according to any one of claims 1 to 3.

5. moreover, In the second operating state, operating the first brake product (1) in response to the first calibration data and the sensor data; or operating the second brake product (2) in response to the second calibration data and the sensor data; Including, 5. The method according to any one of claims 1 to 4.

6. operating the first brake product (1) additionally according to pre-stored second calibration data, or operating the second brake product (2) additionally according to the previously stored first calibration data; The method of claim 5.

7. The first and second calibration data are static calibration data representing the fixed hardware characteristics of said sensors (4, 5); and / or dynamic calibration data representing variable characteristics of said sensors (4, 5); Including, 7. The method according to any one of claims 1 to 6.

8. moreover, In the second operating state, outputting a warning notification to a user that the brake system (10) is in the second operating state; Including, 8. The method according to any one of claims 1 to 7.

9. moreover, operating the brake system (10) in the first operating state if it is determined that the first brake product (1) can communicate with the second brake product (2) via a bus system (6) in the second operating state; Including, 9. The method according to any one of claims 1 to 8.

10. moreover, In the first operating state, a step of a user inputting a control command to transition the brake system (10) from the first operating state to the second operating state; operating the brake system (10) in the second operating condition; Including, 10. The method according to any one of claims 1 to 9.

11. A braking system (10) for a vehicle, comprising: a brake pedal (3) through which a user inputs a brake command; a first sensor (4) disposed on the brake pedal (3) and configured to generate first sensor data in response to the brake command; a second sensor (5) disposed on the brake pedal (3) and configured to generate second sensor data in response to the brake command; a first brake product (1) and / or a second brake product (2) communicatively connected to the first and second sensors (4, 5), respectively; Equipped with The braking system (10) is configured to perform the method according to any one of claims 1 to 10. Brake systems for vehicles.

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