Method and control device for operating a vehicle

Abstract

The invention relates to a method for operating a vehicle (300), in which a required total braking torque (100) on at least one wheel (302) of the vehicle (300) is added using a slow dynamic braking actuator (304) of the vehicle (300) and a high dynamic control actuator (308) of the vehicle (300), the braking actuator (304) providing a slow dynamic braking torque (102), and the braking actuator (304) providing a high dynamic braking torque (102). And the adjusting actuator (308) applies the adjusting torque (104) to the braking torque (102).

Description

Field of Technology

[0001] The present invention relates to a method for operating a vehicle, a corresponding control device, and a corresponding computer program product. Background Art

[0002] The braking regulation system of a vehicle can individually set the braking pressure for each wheel with high dynamics through an intake valve, an exhaust valve, and at least one pump. Here, in the case of wheel lock-up, the braking pressure can, for example, be briefly reduced below the braking pressure applied by the driver of the vehicle to the brake pedal of the vehicle, so that the locked wheel can rotate again. Subsequently, the braking pressure can be increased again by the pump until the wheel starts to lock up again. To prevent lock-up over a longer period of time, the braking pressure can always be reduced and increased again.

[0003] To generate a stable yaw moment on the vehicle, for example, when the vehicle is turning, at least one wheel can be decelerated independently of the driver by applying a braking pressure using a pump. Summary of the Invention

[0004] In this context, the method proposed here provides a method for operating a vehicle, a corresponding control device, and a corresponding computer program product according to the independent claims. Advantageous extensions and improvements of the method proposed here result from this description and are described in the dependent claims.

[0005] Advantages of the Invention

[0006] In the method proposed here, a total braking torque is generated on at least one wheel of the vehicle by adding a plurality of partial braking torques. The partial braking torques are generated by actuators with different response speeds or that can be changed at different speeds. The actuators have different operating principles. For example, one partial braking torque can be provided by a mechanical brake, while another partial braking torque can be provided by an electric drive.

[0007] Here, the faster actuator can in particular provide a smaller share of the total braking torque than the slower actuator. For this purpose, a rapid modulation of the total braking torque can in particular be set by changing the partial braking torque of the fast actuator.

[0008] With the method proposed here, inexpensive, in particular mechanical, actuators with slower response characteristics than conventional ESP can be used to brake the vehicle, because the required rapid adaptation of the total braking torque is implemented by an actuator with rapid response characteristics, in particular an electric actuator.

[0009] A method for operating a vehicle is proposed, in which the required total braking torque on at least one wheel of the vehicle is added when using the slow-dynamic braking actuator and the high-dynamic adjustment actuator of the vehicle, wherein the braking actuator provides a slow-dynamic braking torque and the adjustment actuator applies an adjustment torque to the braking torque.

[0010] Furthermore, the concept of an embodiment of the present invention can be regarded as being based on the ideas and insights described subsequently.

[0011] The required total braking torque on the wheels of the vehicle can be set by the driver of the vehicle via the brake pedal of the vehicle. The total braking torque can also be calculated and requested by the control device of the vehicle.

[0012] The slow-dynamic braking actuator can be a hydraulic braking system. Alternatively, the slow-dynamic braking actuator can be an electromechanical brake. The slow-dynamic braking actuator can have a reduced complexity compared to a conventional braking adjustment system, for example, having an ASR or ESP function. The slow-dynamic braking actuator can set the braking torque individually for each wheel, however, no rapid change of the braking torque is provided here.

[0013] The high-dynamic adjustment actuator can be an electric drive for the wheel or the axle of the wheel. The high-dynamic adjustment actuator can change its adjustment torque quickly and precisely. The high-dynamic adjustment actuator can provide a negative or positive adjustment torque. Thus, the high-dynamic adjustment actuator can decelerate or accelerate the wheel or the axle. The high-dynamic adjustment actuator can provide lower power than the slow-dynamic braking actuator.

[0014] The high-dynamic modulation of the total braking torque can be applied to the slow-dynamic braking torque when using the high-dynamic adjustment torque. The slow-dynamic braking torque can only change slowly compared to the high-dynamic adjustment torque. Thus, a rapid change of the total braking torque can be especially controlled when using the high-dynamic adjustment actuator. The slow-dynamic braking torque can slowly follow the change of the total braking torque with a small gradient.

[0015] The sluggish modulation of the total braking torque can be implemented when using the slow-dynamic braking torque.

[0016] The braking torque can be set to be lower than the maximum value of the total braking torque by the nominal value of the adjustment torque. The nominal value of the adjustment torque can basically correspond to the maximum value of the adjustment torque. The nominal value may be slightly lower than the maximum value. By using the nominal value, the service life of the adjustment actuator can be increased. Due to the reduced braking torque, the adjustment actuator can basically be loaded conventionally at any time. Thus, a high recuperation power can be achieved and as little energy as possible is dissipated as heat.

[0017] On multiple wheels of at least one axle of a vehicle, the total braking torque of each wheel can be added while using wheel-individualized braking torques and axle-type adjustment torques. The adjustment actuator can act on multiple wheels simultaneously. In particular, the adjustment actuator can act on two wheels of an axle. Here, the vehicle can have an adjustment actuator on one axle and no adjustment actuator on another axle. The vehicle can also have an adjustment actuator in each axle respectively. Due to the differential transmission of the axle, the same adjustment torque can exist on the wheels of the axle.

[0018] The difference in the total braking torque of multiple wheels of an axle can be set while using different slow-dynamic braking torques. The difference in the total braking torque on the wheels of an axle causes a yaw torque on the vehicle. Since the vehicle has a relatively large mass inertia due to its mass, the vehicle responds much more slowly to the yaw torque than the wheels respond to the total braking torque acting and the current static friction.

[0019] Alternatively, on the wheels of an axle, the total braking torque of each wheel can be added while using wheel-individualized braking torques and wheel-individualized adjustment torques. Each wheel of the axle can have its own adjustment actuator.

[0020] The method is preferably computer-implemented and can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, such as in a driver assistance system.

[0021] The method proposed here also provides a control device in the form of a driver assistance system for the vehicle, wherein the driver assistance system is configured to execute, control, or implement the steps of a variant of the method proposed here in a corresponding device.

[0022] The control device or the driver assistance system 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. For example, the computing unit can be a signal processor, a so-called system ASIC, or a microcontroller for processing sensor signals and outputting data signals according to the sensor signals. The storage unit can be, for example, a flash memory, an EPROM, or a magnetic storage unit. The interface can be configured as a sensor interface for reading sensor signals from sensors and / or an actuator interface for outputting data signals and / or control signals to actuators. The communication interface can be configured to read or output data wirelessly and / or wiredly. The interface can also be, for example, a software module that exists beside other software modules on a microcontroller.

[0023] A computer program product or computer program having program code that can be stored on a machine-readable carrier or storage medium, such as a semiconductor memory, a hard disk memory, or an optical memory, and is used to execute, implement, and / or manipulate the steps of a method according to one of the above-described embodiments, especially when the program product or program is implemented on a computer or device.

[0024] It should be noted that some of the possible features and advantages of the present invention are described herein with respect to different embodiments. Those skilled in the art recognize that the features of the control device and method can be combined, adapted, or replaced in a suitable manner to obtain additional embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Subsequently, embodiments of the present invention are described with reference to the accompanying drawings, where the drawings and the description should not be construed as limiting the present invention.

[0026] Figure 1 A diagram showing the total braking torque added according to an embodiment is shown.

[0027] Figure 2 A diagram showing the applied modulation of the total braking torque added according to an embodiment is shown; and

[0028] FIG. 3 shows a diagram of a vehicle having different braking configurations for using the method according to an embodiment.

[0029] These drawings are only schematic and not to scale. The same reference numerals represent the same or equivalent features. DETAILED DESCRIPTION

[0030] Figure 1 A diagram showing the total braking torque 100 added according to an embodiment on the wheels of a vehicle is shown. The variation of the total braking torque 100 is shown in a graph that plots time on its abscissa and torque on its ordinate.

[0031] The total braking torque 100 is the sum of the braking torque 102 of the slow-dynamic brake actuator on the wheel and the adjustment torque 104 of the high-dynamic brake actuator on the wheel. The variations of the braking torque 102 and the adjustment torque 104 are also shown in the graph.

[0032] The adjustment actuator can provide less power than the brake actuator. The nominal value 106 of the adjustment torque 104 is less than the total braking torque 100. If the required total braking torque 100 is greater than the nominal value 106, then the braking torque 102 of the brake actuator increases, while the adjustment torque 104 remains at its nominal value 106.

[0033] In an embodiment, when the total braking torque 100 is less than the nominal value 106 of the adjustment torque 104, braking occurs only when using the adjustment actuator. If the total braking torque 100 is greater than the nominal value 106, then when using the braking actuator, a sufficient amount of additional braking torque 102 is generated so as to reach the total braking torque 100.

[0034] In an embodiment, the braking torque 102 and the adjustment torque 104 increase in a preset ratio until the nominal value 106 of the adjustment torque 104 is reached. Subsequently, only the braking torque 102 increases.

[0035] Figure 2 A diagram of the applied modulation of the additive total braking torque 100 according to an embodiment is shown. Here, as in Figure 1 the variation processes of the total braking torque 100, the braking torque 102, and the adjustment torque 104 are shown in a graph. Different from the diagram in Figure 1 the total braking torque 100 is not constant here, for example due to periodic ABS adjustment. Here, a substantially constant share of the total braking torque 100 is provided by the braking torque 102. The variable share of the total braking torque 100 is provided by the variable adjustment torque 104.

[0036] By adding these torques, the high dynamic characteristics of the adjustment actuator and the slow dynamic characteristics of the braking actuator are combined within a favorable range.

[0037] Figure 3 shows a diagram of a vehicle 300 with different braking configurations for using the method according to an embodiment.

[0038] In all diagrams, the vehicle 300 has a slow dynamic braking actuator 304 for each wheel 302. The braking actuator 304 can provide an adapted braking torque for each wheel 302 individually. The braking actuator 304 is, for example, a hydraulic braking system of the vehicle 100.

[0039] In Figures 3a to 3c the vehicle 300 has, in addition to the braking actuator 304 for two wheels 302 of at least one axle 306, a high dynamic adjustment actuator 308. The adjustment actuator 308 provides the same adjustment torque axially for two wheels 302. For example, the adjustment actuator 308 is a drive motor of the axle 306.

[0040] In Figure 3a the adjustment actuator 308 acts on the rear axle 306. In Figure 3b the adjustment actuator 308 acts on the front axle 306. In Figure 3c each adjustment actuator 308 acts on the front axle 306 and the rear axle 306.

[0041] In Figures 3d to 3f , the vehicle 300 has its own adjustment actuator 308 for each wheel 302 of at least one axle 306. The adjustment actuator 308 can provide an adapted adjustment torque for each wheel 302 supplied, individually for the wheel. For example, the adjustment actuator 308 is an electric single-wheel drive for the wheel 302.

[0042] In Figure 3d , the adjustment actuator 308 is arranged on the rear axle 306. In Figure 3e , the adjustment actuator 308 is arranged on the front axle 306. In Figure 3f , two adjustment actuators 308 are arranged on the front axle 306 and the rear axle 306 respectively.

[0043] In Figure 3g and Figure 3h , the vehicle 300 has an axle 306 and an adjustment actuator 308 for providing an adjustment torque for two wheels 302 of the axle 306, as well as an axle 306 and respective adjustment actuators 308 for each wheel 302 of the axle 306.

[0044] In Figure 3g , the adjustment actuator 308 acts on two wheels 302 of the front axle 306, while two adjustment actuators 308 act on the wheels 302 of the rear axle 306. In Figure 3h , the adjustment actuator 308 acts on two wheels 302 of the rear axle 306, while two adjustment actuators 308 act on the wheels 302 of the front axle 306.

[0045] Subsequently, possible design options of the present invention are summarized again, or expressed in slightly different terms.

[0046] Hybrid brake modulation achieved through the interaction of multiple single systems is proposed. This proposal relates in particular to the architecture of future brake regulation systems for electric or hybrid vehicles.

[0047] Current brake regulation systems contain, in addition to stability features (e.g., in the form of classic ESP / ABS), an increasingly broad range of functions, such as supporting the driver in brake execution via an electromechanical brake booster (eBKV) or introducing force onto the brake pedal, or auxiliary or partial auxiliary functions achieved through a unit for actively modulating the hydraulic brake pressure (e.g., ESP, eBKV, Boost unit, etc.), without the active participation of the driver. In vehicles with an electric or partially electric drive, the drive motor can be used for deceleration modulation. The braking power is associated with the power of the motor.

[0048] A braking modulation function is described herein, in which the ability for braking force modulation is generated by the interaction of at least two single components. Each single component is furthermore not capable of individually performing a proper braking pressure modulation for, e.g., ABS, VDC. Through the interaction, the known braking force modulation of a hydraulic brake regulation system (such as ESP, IPB, …) can be exhibited.

[0049] The modulation unit is, for example, a deceleration unit that builds a decelerating force by wheel friction modulation, such as a hydraulic or electromechanical brake regulation system. The hydraulic or electromechanical brake regulation system is subsequently referred to as type A.

[0050] Other modulation units are units that have the characteristic of deceleration and acceleration modulation on a wheel, an axle, or two axles or a combination thereof, such as a drive motor in an electric vehicle. One drive motor or multiple drive motors are subsequently referred to as type B.

[0051] Changing requirements and boundary conditions change the possibilities and capabilities of deceleration modulation and (wheel - individualized) braking modulation in future vehicles. Vehicles are increasingly being electrified and thus have the possibility of deceleration modulation through one / more electric motors. Different forms of electromechanical brake systems may also become increasingly common.

[0052] Additional systems can increase the cost and complexity in a vehicle. The method proposed herein describes the functional interaction of different single components such that the single components jointly meet the existing requirements for wheel - individualized braking modulation possibilities. Thus, the individual components can be designed more inexpensively.

[0053] In a passenger vehicle, it is required that the brake regulation system be able to implement wheel - individualized active and passive braking modulation, vehicle regulation displays (ABS, VDC, TCS), active braking modulation in the longitudinal - dynamic vehicle plane to exhibit a deceleration function within the comfort and dynamic ranges, active braking modulation in the axle plane to exhibit a warning vibration function as a longitudinal - dynamic function, and blending when performing regenerative braking with an electric motor to avoid deceleration fluctuations caused by the deceleration characteristics of the electric motor.

[0054] The functional interaction of two single - systems of type A and type B is proposed herein. The combined single - systems can improve subsequent characteristics in the interaction, thereby generating a better braking system for the vehicle, or a conventional brake regulation system can be formed more inexpensively because the necessary capabilities and characteristics are achieved in the interaction of the single - systems.

[0055] The proposed system improves the maximum deceleration modulation ability, improves the maximum frequency of modulation changes with a specific amplitude, and thus improves the maximum deceleration modulation ability when improving the maximum frequency of modulation changes with a specific amplitude.

[0056] The single system has the ability to modulate individually for each wheel, for the axle type, or for the vehicle plane.

[0057] Ideally, at least one single system has the ability to modulate individually for each wheel here.

[0058] The basic principle of interaction is the total effect of the single component on the wheel-road friction value combination.

[0059] As single components, a wheel-individualized hydraulic modulation unit of type A and at least one axle-type modulation unit of type B can interact with each other.

[0060] In an embodiment, a wheel-individualized modulation unit of type A (for example, a hydraulic brake modulation unit in the form of ESP) interacts in combination with an axle-type modulation unit of type B on the rear axle, for example, an electric drive unit on the rear axle. ( Figure 3a )

[0061] In an embodiment, a wheel-individualized modulation unit of type A (for example, a hydraulic brake modulation unit in the form of ESP) interacts in combination with an axle-type modulation unit of type B on the front axle, for example, an electric drive unit on the front axle. ( Figure 3b )

[0062] In an embodiment, a wheel-individualized modulation unit of type A (for example, a hydraulic brake modulation unit in the form of ESP) interacts in combination with axle-type modulation units of type B on the front axle and the rear axle, for example, electric drive units on the front axle and the rear axle. ( Figure 3c )

[0063] As single components, a wheel-individualized hydraulic modulation unit of type A and a wheel-individualized modulation unit of type B can interact with each other.

[0064] In an embodiment, a wheel-individualized modulation unit of type A (for example, a hydraulic brake modulation unit in the form of ESP) interacts in combination with a wheel-individualized modulation unit of type B on the rear axle, for example, an electric drive unit on the rear axle. ( Figure 3d )

[0065] In an embodiment, a wheel-individualized modulation unit of type A (for example, a hydraulic brake modulation unit in the form of ESP) interacts in combination with a wheel-individualized modulation unit of type B on the front axle, for example, an electric drive unit on the front axle. ( Figure 3e )

[0066] In an embodiment, a wheel - specific hydraulic modulation unit of type A (e.g., a hydraulic brake modulation unit in the form of ESP) interacts with a wheel - specific modulation unit of type B on the front and rear axles, e.g., an electric drive unit on the front and rear axles.( Figure 3f )

[0067] As a single component, the wheel - specific hydraulic modulation unit of type A, the axle - type modulation unit of type B, and the wheel - specific modulation unit of type B can interact with each other.

[0068] In an embodiment, a wheel - specific hydraulic modulation unit of type A (e.g., a hydraulic brake modulation unit in the form of ESP) interacts with a wheel - specific modulation unit of type B on the rear axle, e.g., an electric drive unit on the rear axle, and an axle - type modulation unit of type B on the front axle, e.g., an electric drive unit on the front axle.( Figure 3g )

[0069] In an embodiment, a wheel - specific hydraulic modulation unit of type A (e.g., a hydraulic brake modulation unit in the form of ESP) interacts with an axle - type modulation unit of type B on the rear axle, e.g., an electric drive unit on the rear axle, and a wheel - specific modulation unit of type B on the front axle, e.g., an electric drive unit on the front axle.( Figure 3h )

[0070] The functional - characteristic variant of the pure deceleration ability is the total wheel modulation for achieving the desired maximum deceleration ability in single components that cannot individually perform the desired deceleration modulation.

[0071] The functional basic principle of the hybrid - symbiotic genetic method is to utilize the total modulation on the wheels by accessing multiple modulation units of type A and type B. For example, the hydraulic modulation according to type A and the drive motor on the wheels according to type B are combined, and the access to multiple modulation units is carried out such that the actuator can be adjusted faster in response to changes in the target deceleration requirement.

[0072] The adjustment of the increased target requirement can be achieved by increasing the braking torque of the faster actuator of type B. Alternatively, the target deceleration requirement can be adjusted by reducing the braking torque of the faster actuator of type B. By reducing the braking torque and applying the driving power of the fast actuator of type B, the target deceleration requirement can be quickly reduced, so that the total torque on the wheel is quickly reduced. This means that the operating point of the actuator of type A can also be above the target deceleration level and can be compensated by applying the opposite torque of the actuator of type B. Therefore, the dynamic requirements for the slower actuator can be reduced, which can lead to a cheaper design and manufacture of the actuator of type A.

[0073] Functional characteristic variants of wheel pressure modulation for the ABS function that show pure deceleration capabilities are, for example, total wheel modulation to achieve the desired maximum deceleration capabilities in single components that, by themselves, are not able to perform the desired deceleration modulation. Here, modulation units of type A apply braking torques without a dynamic (alternating) share. Modulation units of type B are responsible for the fast dynamic share.

[0074] For the ABS function, the control strategies of typical vehicle regulation interventions are, for example, that wheels with lower wheel-road target forces on an axle are controlled by axle-mounted modulation units (e.g., electric motors). If there is no axle-mounted modulation unit on an axle, then the regulation is carried out by the hydraulic brake regulation system. In an ideal case, frequent ABS instability modulations are taken over by actuators that perform better in terms of modulation changes. In the μ-split case, the Delta value control between the left and right wheels is carried out with actuators of type A. Here, in principle, it is set with yaw moment attenuation so that the vehicle can still be kept under control.

[0075] For the VDC, TCS functions, modulation units of type B are selected during longitudinal dynamic vehicle regulation interventions so that the axle torque / axle slip can be set faster. This results in better vehicle stability. Depending on the topology, the type B intervention can be achieved by reducing the deceleration modulation of type B or by applying acceleration of type B.

[0076] The different individual wheel braking interventions between the left and right wheels are, in principle, set slowly dynamically. The yaw inertia is significantly greater than the wheel or axle inertia, so here, actuators of type A are responsible for setting the Delta value between the left and right wheels. In addition, an attempt is also made to make this intervention even slower dynamically so that the vehicle can be kept under control.

[0077] Finally, it should be noted that terms such as "having", "including", etc. do not exclude

[0078] other elements or steps, and terms such as "a" or "an" do not exclude a plurality.

[0079] The reference signs in the claims should not be regarded as limiting.

Claims

1. A method for operating a vehicle (300), wherein, Adding the required total braking torque (100) on at least one wheel (302) of the vehicle (300) in the case of using the slow-dynamic brake actuator (304) of the vehicle (300) and the high-dynamic adjustment actuator (308) of the vehicle (300), wherein the brake actuator (304) provides a slow-dynamic braking torque (102), and the adjustment actuator (308) applies an adjustment torque (104) to the braking torque (102).

2. The method according to claim 1, wherein The high-dynamic modulation of the total braking torque (100) is applied to the slow-dynamic braking torque (102) in the case of using the high-dynamic adjustment torque (104).

3. The method according to any one of the preceding claims, wherein, The inertia modulation of the total braking torque (100) is implemented in the case of using the slow-dynamic braking torque (102).

4. The method according to any one of the preceding claims, wherein, The braking torque (102) is set to be lower than the maximum value of the total braking torque (100) by the nominal value (106) of the adjustment torque (104).

5. The method according to any one of the preceding claims, wherein, On a plurality of wheels (302) of at least one axle (306) of the vehicle (300), the total braking torque (100) of each wheel (302) is added in the case of using wheel-individualized braking torques (102) and axle-type adjustment torques (104).

6. The method according to claim 5, wherein, The difference in the total braking torque (100) of the plurality of wheels (302) of the axle (306) is set in the case of using different slow-dynamic braking torques (102).

7. The method according to any one of the preceding claims, wherein, The adjustment torque (104) can be set to be negative or positive.

8. A control device, wherein, The control device is configured to implement, realize, and / or control the method according to any one of the preceding claims in the corresponding device.

9. A computer program product, the computer program product being configured to cause a processor to implement, realize, and / or control the method according to any one of claims 1 to 7 when the computer program product is implemented.

10. A machine-readable storage medium, on which the computer program product according to claim 9 is stored.

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