Method for controlling brake actuators, control device for a brake system, and brake system

Abstract

The invention relates to the control of brake actuators in a brake system comprising at least one friction brake. After a deceleration request is received, the brake actuators in the brake system are controlled such that the requirement according to the deceleration request is satisfied, and additionally the braking force is distributed such that as little noise as possible is developed. In the process, the braking force is distributed while taking into consideration a previously ascertained relationship between the control of the brake actuators and a corresponding noise development. This relationship can be ascertained during the braking process by modulating the individual brake actuators and monitoring the resulting noise development, and the relationship can then be stored.

Description

[0001] Description

[0002] title

[0003] Method for controlling brake actuators, control device for a brake system and brake system

[0004] Technical area

[0005] The present invention relates to a method for controlling brake actuators in a braking system with multiple brake actuators. The present invention further relates to a control device for a braking system with multiple brake actuators and a braking system with multiple brake actuators.

[0006] background

[0007] In addition to the drive system, the braking system plays a central role in motor vehicles. Today's motor vehicles are typically equipped with hydraulic brakes, which can be centrally applied with pressure for braking, for example, by the driver or an actuator. The pressure can be individually adjusted for each wheel by controlling the appropriate valves.

[0008] Furthermore, decentralized, wheel-specific concepts based on electromechanical actuators, as well as wheel-specific electrohydraulic actuators, are also known. For example, these allow individual braking force to be generated for each wheel, independent of the brake pedal, to implement a desired deceleration.

[0009] For example, the publication DE 10 2018 210 021 A1 describes a method for operating a braking system for a motor vehicle with a hydraulic braking device and an electromechanical braking device. In all concepts based on friction brakes, braking noise can occur during braking. Due to the complexity of the mechanisms that generate braking noise, predicting such braking noise is a major challenge. Therefore, it is also difficult to prevent or at least reduce the resulting braking noise.

[0010] Disclosure of the invention

[0011] The present invention provides a method for controlling brake actuators in a braking system, a control device for a braking system, and a braking system having the features of the independent patent claims. Further advantageous embodiments are the subject of the dependent patent claims.

[0012] Accordingly, it is provided:

[0013] A method for controlling brake actuators, in particular for controlling brake actuators in a braking system with multiple brake actuators. The method comprises a step for receiving a request for a deceleration request. The deceleration request can be specified, for example, by a user or a driver assistance system. The method further comprises a step for controlling the brake actuators. The brake actuators can be controlled using a previously determined and stored relationship between the control of the brake actuators and a corresponding noise development. This relationship can be read out, for example, from a memory device that has stored the relationship between the control of the brake actuators and the corresponding noise development in any desired manner.

[0014] Furthermore, it is planned:

[0015] A control device for a braking system with multiple brake actuators. The control device is configured to receive a request for a desired deceleration. The request can be specified, for example, by a driver assistance system or by a user, for example, by actuating a brake pedal or the like. Furthermore, the control device is configured to read out a previously stored relationship between the activation of the brake actuators and the development of noise. For example, the relationship can be read out from a memory device that has stored the corresponding relationship in any suitable manner. Furthermore, the control device is configured to activate the brake actuators.In particular, the control device is designed to control the brake actuators using the received request for the deceleration request and the stored relationship between the control of the brake actuators and the noise development.

[0016] Finally, it is planned:

[0017] A braking system with several brake actuators and a control device according to the invention.

[0018] Advantages of the invention

[0019] The present invention is based on the finding that braking noise can occur when a friction brake is applied in a vehicle. Furthermore, the present invention is based on the finding that the mechanisms that cause these braking noises are highly parameter-dependent and therefore difficult to predict. However, especially at low driving speeds, braking noises are often perceived as annoying by users.

[0020] Therefore, the idea of ​​the present invention is to take this insight into account and create a concept that can prevent or at least reduce brake noise in the simplest possible way. The inventive concept can be implemented relatively easily and without significant additional hardware expenditure.

[0021] To control the brake actuators, a previously determined relationship between the actuation of the brake actuators and the noise generated by the respective brakes is stored. This stored relationship between the actuation of the brake actuators and the associated noise generation can be used to control the individual brake actuators for a desired deceleration request in such a way that the noise generation is as low as possible. In other words, for a predetermined deceleration corresponding to a received deceleration request, the previously determined and stored relationship between the actuation of the individual brake actuators and the corresponding noise generation can be used to find the optimal actuation of the individual brake actuators, whereby the brakes and the brake actuators produce the lowest possible noise generation.

[0022] In total, the individual brake actuators are actuated in such a way that the resulting brake deceleration corresponds to the requested deceleration. If necessary, any other specifications and framework conditions can also be taken into account. For example, specifications regarding vehicle stability, known friction coefficients between tires and road surface, can also be considered when allocating the actuation of the individual brake actuators.

[0023] The brake actuators can, in principle, be any suitable brake actuator, in particular brake actuators for operating a friction brake. For example, the brake actuators can be electromechanical, electrohydraulic, or other suitable brake actuators.

[0024] The relationship between the control of a brake actuator and the corresponding noise development can be stored in any suitable way. For example, the relationship can be stored in the form of a look-up table or similar. However, other tabular or formulaic characterizations of the relationship between the control of the brake actuator and the corresponding noise development are also possible.

[0025] The relationship between the control of the brake actuators and the corresponding noise generation can be stored, for example, in a memory device. For this purpose, the memory device can be integrated, for example, into the control device for the braking system. Alternatively, an external memory device can also be provided.

[0026] According to one embodiment, the method for controlling the brake actuators can further comprise a step for detecting noise development at the controlled brake actuators. In this case, for example, individual detection of the noise development at each controlled brake actuator is possible. However, joint detection of several or all controlled brake actuators is also possible in principle. Furthermore, the method can comprise a step for varying the control of the brake actuators. The control of the brake actuators can in particular take place while maintaining or sustaining the request for the received deceleration request. In other words, the control of the brake actuators is varied or modulated in such a way that, overall, the deceleration is maintained as constant as possible.Furthermore, the method can include a step for determining a relationship between the control of the brake actuators and the detected noise development. For this purpose, the noise development occurring during the variation or modulation of the control of the brake actuators can be detected in particular in order to determine the relationship between the control of the brake actuators and the noise development. This determined relationship can then be stored. In particular, the relationship can be stored, for example, in the previously mentioned storage device. In this way, the relationship between the control of the brake actuators and the resulting noise development can be determined during operation.This relationship can then be used to find the most optimal configuration for controlling the individual brake actuators for the lowest possible noise generation, in accordance with a deceleration requirement.

[0027] According to one embodiment, the noise development is detected using acoustic sensors in a spatial environment of the brake actuators. For this purpose, acoustic sensors such as microphones or similar devices can be used. The acoustic sensors can be positioned, for example, in the area of ​​a wheel house or at another suitable location near the braking system. Furthermore, the use of existing sensors to detect acoustic signals in the area of ​​the brake actuators or brakes is also possible. Additionally or alternatively, the noise development can also be detected using acoustic sensors in the passenger compartment of a motor vehicle, for example, using an interior microphone or similar device. Such an interior microphone can also be provided, for example, for voice inputs from a user or similar.This means that existing acoustic sensors can also be used to record noise levels.

[0028] According to one embodiment, the control of the brake actuators can be varied individually for each brake actuator. This makes it particularly easy to assign any noise generated to a brake actuated by the respective brake actuator. Alternatively, it is also possible, for example, to modify the control variation of the brake actuators jointly for all brake actuators on a common axle. Furthermore, the control of the brake actuators on one side of the vehicle can also be modified or modulated jointly.

[0029] According to one embodiment, a relationship between the control of the respective brake actuator and the corresponding noise development is determined individually for each brake actuator. This provides precise knowledge of the causes of the respective noise developments during a braking process.

[0030] According to one embodiment, the method further comprises a step for determining at least one environmental parameter of the braking system. Such an environmental parameter can be, for example, an ambient temperature, a brake temperature, information from a moisture sensor, or any other suitable environmental parameter. The environmental parameters can, for example, be detected by sensors and / or estimated or calculated.

[0031] The above embodiments and developments can be combined with each other as desired, where appropriate. Further embodiments, developments, and implementations of the invention also include combinations of features of the invention not explicitly mentioned above or described below with respect to the exemplary embodiments. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic forms of the invention.

[0032] Short description of the drawings

[0033] Further features and advantages of the invention are explained below with reference to the figures. These show:

[0034] Fig. 1: a schematic representation of a block diagram of a braking system with a control device according to one embodiment; and Fig. 2: a flowchart of how a method for controlling brake actuators according to one embodiment can be based.

[0035] Description of embodiments

[0036] Figure 1 shows a schematic representation of a block diagram for a braking system with a control device for controlling brake actuators according to one embodiment. The exemplary embodiment shown in Figure 1 shows a braking system such as can be used, for example, for a motor vehicle with two axles. However, the present invention is not limited to such a configuration. Rather, the inventive principle can generally be applied to braking systems that have at least two brakes or brake actuators.

[0037] The exemplary embodiment according to Figure 1 comprises four brakes 21 to 24. Each brake 21 to 24 can be assigned to a corresponding wheel. For example, the brakes 21 and 22 can be assigned to a front axle, with the first brake 21 being assigned to a left front wheel and the second brake 22 being assigned to a right front wheel. Analogously, the two further brakes 23 and 24 can be assigned to a rear axle, with the third brake 23 being assigned to a left rear wheel and the fourth brake 24 being assigned to a right rear wheel. However, it is understood that other configurations are also possible. Each brake 21 to 24 is actuated by means of a corresponding actuator 31 to 34. In principle, any suitable actuators are possible. For example, the brakes 21 to 24 can be hydraulically actuated brakes.In particular, the brakes 21 to 24 can be electrohydraulically actuated brakes. Alternatively, electromechanically actuated brakes 21 to 24 are also possible. In this case, an electrically actuated actuator 31 to 34 can exert a force on a brake disc or brake drum.

[0038] The actuators 31 to 34 of the brakes 21 to 24 can be controlled via a control device 10. This control device 10 can, for example, adjust or dose the force exerted by the actuators 31 to 34 on the brakes 21 to 24. Depending on the technology (electrohydraulic, electromechanical, etc.), the control device 10 can be designed accordingly. However, since the basic principle for controlling such brakes 21 to 24 is already considered known, further explanation will be omitted here.

[0039] When the brakes 21 to 24 are activated, a braking noise may be generated. This braking noise may be perceived as annoying by the user or by other persons, for example, in the vicinity of the vehicle. Therefore, the invention provides a concept for preventing or at least reducing this braking noise.

[0040] For a braking operation, the control device 10 can receive a request for a desired deceleration. This request can be issued, for example, by a user by pressing a brake pedal or the like. Alternatively, the request for the desired deceleration can be issued by a control component of a driver assistance system or a system for autonomous driving. In response to such a request, the control device 10 can control the actuators 31 to 34 of the brakes 21 to 24 such that a braking effect is realized in accordance with the request. The control device 10 can control the actuators 31 to 34 individually. For example, the control device 10 can control the actuators 31 to 34 such that the braking force required to fulfill the request is distributed between the front axle and the rear axle, taking other boundary conditions into account.In addition to the general conditions for stabilizing the vehicle during braking, the control device 10 can also take into account the noise generated when the brakes 21 to 24 are applied.

[0041] To account for noise generation, the control device 10 can consider a previously determined relationship between the activation of the actuators 31 to 34 and the corresponding noise generation at the brakes 21 to 24. Such a relationship can be stored, for example, in a memory device 11 of the control device 10. In principle, however, the memory device 11 can also be provided outside the control device 10.

[0042] To reduce braking noise while fulfilling a deceleration request, the control device 10 can therefore adjust the braking force at the individual brakes 21 to 24 such that, on the one hand, a deceleration can be achieved in total in accordance with the request, and in doing so, actuate the individual actuators 31 to 34 such that the noise development at the brakes 21 to 24 is as minimal as possible. For example, the control device 10 can distribute the braking force at the brakes 21 and 22 of the front axle or at the brakes 23 and 24 of the rear axle according to the request such that the noise development during braking is as minimal as possible. If necessary, the distribution of the braking force between the left and right sides can also be adjusted such that the noise development during braking is minimized.For example, the left front wheel brake 21 and the right rear wheel brake 24 can be actuated with a higher braking force, while the right front wheel brake 22 and the left rear wheel brake 23 can be actuated with a lower braking force if this is expected to result in less noise compared to a uniform actuation. In principle, however, any other concepts for distributing the braking force between the individual brakes 21 to 24 are also possible.

[0043] Particularly in the case of electrically powered motor vehicles, a ratio between deceleration by means of friction brakes 21 to 24 on the one hand and deceleration by means of recuperation can also be adjusted if necessary in order to minimize noise development during braking.

[0044] In addition, it is also possible, for example, to set a drive torque on one (driven) axle and at the same time set an increased braking torque on another (braking) axle, so that the deceleration request can be met in accordance with the requirement.

[0045] However, in all concepts for reducing brake noise, the individual control of the brake actuators 31-34 is only adjusted within a range where the vehicle's driving stability is ensured. In other words, minimizing noise is subordinate to maintaining driving stability during braking.

[0046] Since the noise development at the brakes 21 to 24 depends on numerous parameters, other parameters, in particular environmental parameters, can also be taken into account. For example, the ambient or outside temperature, a temperature of the brakes 21 to 24, wetness or humidity in the area surrounding the vehicle or the brakes, or any other external parameters can be taken into account. These additional parameters can either be recorded by sensors or calculated on the basis of suitable models. If such additional parameters are available, a relationship between the generation of the braking noise, the control of the brake actuators 31 to 34, and the other parameters can be determined and saved in advance. This relationship can be used accordingly to distribute the braking force between the individual brakes 21 to 24 orThe required control of the brake actuators 31 to 34 can be determined in advance and stored, for example, in the memory device 11. Thus, this previously determined and stored relationship can be used to determine an optimal distribution in the control of the brake actuators 31 to 34 for minimal noise generation.

[0047] Since the generation of braking noise can change over the service life of brakes 21 to 24, the relationship between the control of brake actuators 31 to 34 and the resulting noise during a braking operation, as well as the further relationship depending on additional parameters during vehicle operation, particularly during braking operations, can be determined. The newly determined relationship can then be saved and used for subsequent braking operations.

[0048] For this purpose, one or more noise sensors 40 to 44 can be provided. The noise sensors 40 to 44 can, for example, be microphones or other sensors suitable for sensing the generation of braking noise. For example, a microphone 40 can be provided in the interior of a passenger compartment. Such an interior microphone 40 can, for example, be a microphone that also records voice commands from a user. However, other interior microphones 40 are also possible. In addition, acoustic sensors 41 to 44 can also be provided in the area of ​​the brakes 21 to 24. For example, microphones or the like can be provided in a wheel house or at another suitable position in order to record the noises generated during the braking process.

[0049] The signals from the acoustic sensors 40 to 44 can be provided to the control device 10. Thus, the control device 10 can determine a relationship between the current control of the actuators 31 to 34 and the associated noise generation.

[0050] Furthermore, the control device 10 can vary or modulate the control of the actuators 31 to 34 during a braking operation. In particular, the control of the individual actuators 31 to 34 can be modulated such that the total braking force exerted by the brakes 21 to 24 remains at least approximately constant. Thus, a user will not perceive any noticeable effect from this variation in the control. During such a modulation of the control of the actuators 31 to 34 during the braking operation, the control device 10 can receive the signals from the acoustic sensors 40 to 44 and determine a relationship between the control of the actuators 31 to 34 and the resulting noise development. This relationship can then be stored, for example, in the memory device 11.Here too, if available, further parameters, in particular further environmental parameters, can be taken into account when determining the relationship between noise generation, control of the actuators and, if applicable, other parameters.

[0051] Figure 2 shows a flowchart that may underlie a method for controlling brake actuators in a braking system according to one embodiment. The method may, in principle, include any additional steps, as previously described in connection with the braking system shown in Figure 1. Likewise, the braking system described above may include any components that may be required to implement the method described here.

[0052] In step S1, a request for a desired deceleration is first received. Subsequently, in step S2, the brake actuators 31 to 34 are controlled to set a deceleration on the brakes 21 to 24 according to the request. The individual brake actuators 31 to 34 are controlled in such a way that the brakes 21 to 24 collectively fulfill the requested deceleration and, in addition, the noise level is as low as possible.

[0053] For a (dynamic) determination of the relationship between noise development, control of the brake actuators 31 to 34, and possibly other parameters, the noise development at the brakes 21 to 24 when the brake actuators 31 to 34 are activated can be recorded in a step S3. Furthermore, the activation of the brake actuators 31 to 34 can be varied or modulated in a step S4. However, the modulation of the brake actuators takes place within a framework that, on the one hand, does not affect the stability of the vehicle and, on the other hand, also enables the most constant deceleration torque possible in accordance with the requirement.

[0054] In step S5, a relationship can then be established between the activation of the brake actuators 31 to 34 and the detected noise development. This relationship can then be stored in step S6. In particular, the relationship between the activation of the brake actuators 31 to 34 and the detected noise development can be stored in a memory device 11.

[0055] In summary, the present invention relates to a control of brake actuators in a braking system with at least one friction brake. Upon receipt of a deceleration request, the brake actuators in the braking system are controlled in such a way that, on the one hand, the requirement according to the deceleration request is met and, on the other hand, the braking force is distributed in such a way that the noise development is as low as possible. The distribution of the braking force takes into account a previously determined relationship between the control of the brake actuators and a corresponding noise development. This relationship can be determined and stored during braking by modulating the individual brake actuators and monitoring the resulting noise development.

Claims

Claims 1. Method for controlling brake actuators (31-34) in a braking system, comprising the steps: Receiving (Sl) a request for a delay request; Controlling (S2) the brake actuators (31-34) using a previously determined and stored relationship between a control of the brake actuators (31-34) and the corresponding noise development.

2. Method according to claim 1, comprising the steps: Detecting (S3) noise development at the controlled brake actuators (31-34); Varying (S4) the control of the brake actuators (31-34), in particular while maintaining the request for the desired deceleration; Determining (S5) a relationship between the control of the brake actuators (31-34) and the recorded noise development; and Saving (S6) the determined relationship between the control of the brake actuators (31-34) and the recorded noise development.

3. The method according to claim 2, wherein the detection (S3) of the noise development is carried out using acoustic sensors (41-44) in a spatial environment of the brake actuators (31-34) and / or using an interior microphone (40) in a vehicle.

4. The method according to claim 2 or 3, wherein the varying (S4) of the control of the brake actuators (31-34) is carried out individually for each brake actuator (31-34) and / or jointly for all brake actuators (31-34) of a common axle.

5. The method according to one of claims 2 to 4, wherein the determination (S5) of the relationship between the activation of the brake actuators (31-34) and the detected noise development determines an individual relationship between activation and noise development for each brake actuator (31-34).

6. Method according to one of claims 1 to 5, comprising the steps Determining at least one environmental parameter of the braking system, wherein the actuation (S2) of the brake actuators (31-34) is further carried out using the determined at least one environmental parameter.

7. The method of claim 6, wherein the at least one environmental parameter comprises an ambient temperature, a brake temperature and / or information from a wetness sensor.

8. Control device (10) for a braking system with a plurality of brake actuators (31-34), wherein the control device (10) is designed to: receive a request for a deceleration request, read out a previously stored relationship between a control of the brake actuators (31-34) and a noise development, and control the brake actuators (31-34) using the received request for the deceleration request and the stored relationship between the control of the brake actuators (31-34) and the noise development.

9. Control device (10) according to claim 8, wherein the control device is further configured to: detect a noise development at the controlled brake actuators (31-34), vary the control of the brake actuators (31-34), determine a relationship between the control of the brake actuators (31-34) and the detected noise development, and storing the determined relationship between the control of the brake actuators (31-34) and the detected noise development in a memory device.

10. A braking system comprising: a plurality of brake actuators (31-34); and a control device according to claim 8 or 9.

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