Method for controlling a braking torque of a vehicle during an at least partially automated driving uphill and / or downhill, computing device and assistance system for a vehicle

Abstract

Method for controlling a braking torque of a vehicle (1) during an at least partially automated driving uphill and / or downhill by means of an assistance system (3), wherein the assistance system (3) is set up for at least partially automated longitudinal guidance of the vehicle (1), comprising the steps: - Receiving standstill data as soon as a future temporary standstill of the vehicle (1) is requested by the assistance system (3) during the at least partially automated driving uphill and / or downhill, - Continuously receiving speed values ​​(vx) describing a speed of the vehicle (1) during a deceleration of the vehicle (1) before the temporary standstill, - Continuous determination of slope data that describe an angle of inclination or gradient, - Continuous calculation of a changed speed value (vx ge), which depends on the speed value (vx) and the slope data, - Output of an electronic control signal to control the braking torque to ensure the temporary standstill of the vehicle (1) as soon as the changed speed value (vx ge ) falls below a predetermined threshold value (14) and the standstill data are received, and - the changed speed value (vx ge ) is calculated in such a way that, in comparison to the speed value (vx), it falls below the predetermined threshold value (14) all the sooner the greater the angle of the incline or decline.

Description

[0001] The present invention relates to a method for controlling a braking torque of a vehicle during at least partially automated driving uphill and / or downhill using an assistance system. Furthermore, the present invention relates to a computing device for a vehicle assistance system. Finally, the present invention relates to an assistance system for a vehicle.

[0002] Distance-based cruise control in a vehicle, also known as Adaptive Cruise Control (ACC), is a decisive step towards automated driving. The driver initially sets a desired speed, which is then automatically maintained by the vehicle using the distance-based cruise control. Additional distance sensors, such as a radar sensor or a camera, also enable extremely comfortable driving in convoy traffic. The distance sensor makes it possible to constantly monitor the distance to a road user ahead. If the road user ahead slows down, for example, the distance-based cruise control can reduce the speed set by the driver, meaning no intervention by the driver is necessary and comfortable driving in convoy is still possible. Even if the vehicle in front or the other vehicle in front is slowing down, the distance-based cruise control can reduce the speed set by the driver.If the road user ahead accelerates, the distance-based cruise control accelerates the vehicle until the desired speed and / or the speed of the vehicle ahead is reached. It may also be necessary to briefly brake the vehicle to a standstill. This may be necessary, for example, in stop-and-go traffic or at traffic lights.

[0003] A special situation arises for the adaptive cruise control system when driving uphill and / or downhill. If adaptive cruise control is activated and the vehicle in front brakes to a stop, the adaptive cruise control system must also brake the vehicle to a stop. Braking is usually performed by controlling the braking torque or pressure so that the vehicle comes to a stop as smoothly as possible. In other words, the braking torque or pressure is reduced shortly before the vehicle comes to a stop, preventing a sudden stop.

[0004] However, if the vehicle is now on an uphill or downhill gradient, it may happen that the vehicle rolls unintentionally by a few centimeters due to the reduced braking torque or reduced brake pressure and the incline or decline. This is usually because additional braking torque, which prevents the vehicle from rolling unintentionally or ensures a temporary standstill, is only generated when the speed falls below a threshold. This threshold could be 0.1 m / s, for example. Furthermore, the vehicle may roll, particularly after previous significant deceleration or during heavy braking.

[0005] To counteract the problem of unintentional rolling during a temporary stop on an uphill or downhill gradient, the additional braking torque can be applied earlier to secure the temporary stop. In other words, the threshold below which the braking torque builds up can be increased. For example, a threshold of 0.4 m / s could be specified instead of 0.1 m / s. The disadvantage of increasing the threshold is a reduction in comfort on level ground. Raising the threshold can lead to uncomfortable, jerky stops on level ground.

[0006] The publication DE 10 2006 056 627 A1 discloses a method for ensuring that a motor vehicle comes to a standstill. Before reaching a standstill, an electronic control unit checks whether a specified gradient threshold has been exceeded, whether the vehicle speed has fallen below a specified threshold, and whether negative vehicle acceleration (deceleration) is present. If all three conditions are met simultaneously, an increased target braking torque is applied until the vehicle comes to a standstill.

[0007] Document DE 10 2011 100 944 A1 discloses a method for adaptive cruise control on a slope for improving driving behavior on a slope and behavior when maintaining a stopped state on a slope. During adaptive cruise control, a road gradient is estimated based on vehicle acceleration and longitudinal acceleration to enable compensation of a resistance torque with respect to the road gradient, thereby preventing deterioration of a vehicle's driving speed on a slope. Compensation of a braking torque to prevent the vehicle from being pushed backward when the vehicle is stopped on a slope or when it is started on a slope to drive off can also prevent deterioration of the behavior on a slope.

[0008] The published patent application DE 10 2016 114 755 A1 describes a vehicle including an engine with auto-stop and auto-start functions. The vehicle additionally includes a braking system configured to apply braking torque to vehicle wheels. The vehicle further includes a controller configured to control the engine and the braking system via an ACC system in response to a detected forward object. The controller is configured to automatically control the braking system in response to a distance to the detected forward object falling below a first, predefined threshold and a vehicle speed falling below a second, predefined threshold. In response to these inputs, the controller automatically controls the braking system to apply braking torque to keep the vehicle stationary in the absence of driveline torque based on a current road gradient.The controller also commands the motor to auto-stop in response to these inputs.

[0009] The document DE 10 2013 111 063 A1 relates to a method for automatically stopping a vehicle, in particular a motor vehicle, on an incline. A driver causes the vehicle to stop on the incline, the vehicle rolling to a stop on the incline essentially uninfluenced by the driver, and subsequently, the vehicle is automatically brought into a stopping position. Furthermore, the document describes a computer program product, a processing device, or a computing unit, and a safety device or a safety system, in particular a driver assistance system, for a vehicle, in particular a motor vehicle.

[0010] It is an object of the present invention to show a solution how the control of a braking torque in the at least partially automated operation of a vehicle while driving uphill and / or downhill can be improved by means of an assistance system in such a way that safe and comfortable driving is possible.

[0011] This object is achieved according to the invention by a method, a computing device, and an assistance system for a vehicle having the features according to the independent claims. Advantageous developments of the present invention are specified in the dependent claims.

[0012] A method according to the invention is used to control a braking torque of a vehicle during at least partially automated driving up an uphill and / or downhill slope by means of an assistance system. The method comprises receiving standstill data as soon as a future temporary standstill of the vehicle is requested by the assistance system during the at least partially automated driving up the uphill and / or downhill slope. Furthermore, the method comprises continuously receiving speed values ​​that describe a speed of the vehicle during a deceleration of the vehicle before the temporary standstill. In addition, the method comprises continuously determining slope gradient data that describe an angle of the uphill or downhill slope. Furthermore, the method comprises continuously calculating a changed speed value that is dependent on the speed value and the slope gradient data.Finally, the method comprises outputting an electronic control signal for controlling the braking torque to ensure the temporary standstill of the vehicle as soon as the changed speed value falls below a predetermined threshold and the standstill data are received.

[0013] The method is intended to control the braking torque provided by the vehicle's brakes. The braking torque is to be controlled by the assistance system during at least partially automated operation of the vehicle while the vehicle is driving on a road with an uphill or downhill gradient and the vehicle is braked to a standstill. In particular, the method is intended to prevent the vehicle from rolling during braking until it comes to a standstill, and to make braking as comfortable as possible for the driver of the vehicle. For example, when driving uphill, the driver of the vehicle may specify a desired speed of 30 km / h for the distance-based cruise control. It may also be the case that a road user ahead reduces their speed or brakes to a standstill.Distance-based cruise control can now also reduce speed and brake to a standstill. The braking maneuver, and thus the braking torque or brake pressure, is controlled in such a way that a sudden stop or deceleration of the vehicle is avoided. In particular, the braking maneuver should be as comfortable as possible for the driver due to the change from a dynamic driving state to a temporary standstill. Furthermore, safety should be ensured and rolling of the vehicle should be avoided.

[0014] In order to provide sufficient braking torque to prevent the vehicle from rolling, even on an uphill or downhill gradient, it is first necessary to determine that a temporary standstill of the vehicle is desired in the near future. The assistance system can therefore request a future temporary standstill using the standstill data. For example, this can be done in the form of binary information and / or distance-based information. Using the continuously received speed values, it can be determined at what point the vehicle is so slow that it is almost stationary and should therefore be prevented from rolling.

[0015] If the state changes from the dynamic driving state to a temporary standstill, the braking torque can be provided to secure the standstill. However, this change of state can also depend on the gradient of the road. The greater the angle of the incline or decline, the sooner a change of state may be necessary. This is because, for example, the greater the angle of the incline, the greater the downhill force and thus the deceleration when driving uphill. If the change of state were to only occur when a predetermined speed is undershot, the vehicle could briefly roll backward unintentionally on a steep incline.

[0016] It is intended that the slope gradient data, which describes the angle of the ascent or descent, will be determined continuously. The slope gradient data can also be determined for future sections of the roadway that the vehicle will travel through. The angle of the ascent or descent can be determined for the roadway on which the vehicle is currently located. The angle can also be determined for the section of the roadway in which the vehicle is expected to brake to a standstill.

[0017] By continuously determining slope gradient data, i.e., the angle of the incline or decline, a modified speed value can be continuously calculated. Using the modified speed value, the slope gradient can be taken into account during the state change, i.e., the transition from a dynamic state to a temporary standstill state. The modified speed value can be calculated in such a way that, when driving up an incline using an assistance system, the greater the angle of the incline, the sooner it falls below the specified threshold compared to the speed value.In other words, with the help of the changed speed value, it can be determined when the state change from a dynamic driving state to a temporary standstill of the vehicle should take place depending on the slope gradient data and when the braking torque should consequently be built up or provided to ensure the temporary standstill.

[0018] The changed speed value can be continuously determined based on the speed value and the slope data, which describes the current speed of the vehicle. The speed value, which describes the current speed of the vehicle, can be determined based on a speed sensor of the vehicle. The changed speed value can be determined using a calculation rule or a formula that depends on the speed value and the slope data. This can result in a non-linear relationship between the speed value and the changed speed value depending on the angle. Furthermore, different calculation rules can be used for inclines and declines.

[0019] If the changed speed value falls below the predetermined threshold, the state change from "active" to "temporary standstill" can occur, and the braking torque can be provided. In contrast to the prior art, the state change is therefore not only dependent on the actual speed of the vehicle. According to the invention, the state change is based on the changed speed value, which additionally takes into account at least the angle of the roadway. Using the method according to the invention, the braking torque can therefore be provided in such a way that the vehicle is always prevented from rolling during a temporary standstill. Furthermore, the braking torque can be controlled so that the braking maneuver offers the greatest possible comfort and safety for the vehicle driver, regardless of the gradient of the slope.

[0020] In one embodiment, additional acceleration data describing the acceleration or deceleration of the vehicle prior to the temporary standstill are received and / or determined. The changed speed value can thus also be determined based on the acceleration data. It is advantageous if the acceleration or deceleration of the vehicle is taken into account when calculating the changed speed value. For example, if a sudden braking maneuver is necessary due to a preceding road user in the case of activated distance-based cruise control, the state change and thus the threshold value of the changed speed value should be undershot significantly earlier than with gentle braking.This is the only way to ensure that, depending on the gradient of the slope as well as on the acceleration of the vehicle, in particular the deceleration of the vehicle, the vehicle is prevented from rolling, in particular from rolling back, during a temporary standstill as a result of a heavy braking manoeuvre.

[0021] The acceleration data can be provided by an acceleration sensor in the vehicle. It is also possible for the acceleration data to be determined based on the continuously received speed values. For example, the acceleration or deceleration of the vehicle before a temporary standstill can be determined by a time derivative of the vehicle's speed. In particular, acceleration can be understood as the ratio of a speed difference to a time difference.

[0022] Furthermore, the acceleration data can also be used to improve the estimate of the angle of the incline or decline. If the slope gradient is measured using an acceleration sensor, for example, this measurement can be influenced by the vehicle's acceleration or deceleration. Using the acceleration data, the estimate of the slope gradient can be corrected and thus improved.

[0023] Overall, acceleration data can be used to improve the control of a vehicle's braking torque during at least partially automated driving uphill and / or downhill using an assistance system. This prevents the vehicle from rolling and improves driver comfort.

[0024] It is also advantageous if the changed speed value is calculated in such a way that the greater the vehicle's acceleration or deceleration, the sooner it falls below the specified threshold compared to the speed value. If one visualizes the temporal progression of the continuously determined changed speed value and the temporal progression of the continuously determined speed value while driving uphill or downhill, the graph of the temporal progression of the changed speed value lies below the graph of the speed value. In other words, the changed speed value is smaller than the speed value when driving uphill during a braking maneuver. One could also say that the changed speed value leads the speed value.The changed speed value falls below the specified threshold sooner the greater the deceleration of the vehicle.

[0025] A further advantageous embodiment provides that the changed speed value is calculated in such a way that, compared to the speed value, it falls below the specified threshold value earlier the greater the angle of the incline or decline. Analogous to the previous example, the changed speed value can therefore lead the speed value further the greater the angle of the incline or decline. For example, the changed speed value can differ from the speed value by a negative additive element. The negative additive element can, for example, be designed as a product of the acceleration or deceleration of the vehicle and a gradient-dependent time element. Overall, a changed speed value can thus be calculated that takes into account both the gradient of the slope and the acceleration of the vehicle.In particular, the assistance system can increase the comfort for the driver of the vehicle during a braking maneuver when driving up or down an incline.

[0026] A further embodiment provides that the electronic control signal is output in such a way that the braking torque for securing the temporary standstill of the vehicle is greater the greater the acceleration or deceleration of the vehicle and / or the greater the angle of the incline or decline. To improve the control of the braking torque, in addition to using a modified speed value, the use of an incline- and / or acceleration-dependent braking torque can be advantageous. For example, the greater the angle of the incline or decline, the faster the braking torque provided for securing the temporary standstill can be available.Assuming the braking torque to ensure the temporary stop of the vehicle is applied when the speed threshold of 0.1 m / s is undershot, the time until the vehicle rolls back on an incline decreases depending on the angle of the incline. Consequently, the greater the angle of the incline or decline, the earlier or faster the braking torque can be applied. Combined with the changed speed value, this results in a particularly advantageous design for controlling the vehicle's braking torque.

[0027] The braking torque can also be determined depending on the angle and / or deceleration. As the angle and / or deceleration increase, the braking torque can be increased, or a higher braking torque can be maintained. In principle, the curve of the provided braking torque can exhibit a PT1 behavior to prevent overshoot. The maintained braking torque can also be referred to as the braking torque reserve.

[0028] It is also advantageous if data from an acceleration sensor and / or digital map data are received to determine the slope gradient data, which describes the angle of the uphill or downhill gradient. For example, gradient or uphill gradient information can be stored in digital map data. Using a satellite-based positioning system and the digital map data, the slope gradient can be determined particularly precisely. In other words, the angle of the uphill or downhill gradient can be determined. Furthermore, the use of digital map data has the advantage of enabling proactive driving and thus proactive braking maneuvers, as well as a particularly convenient initiation of a temporary standstill.

[0029] Finally, an advantageous embodiment provides that the calculation of the changed speed value is carried out if the speed value falls below a predetermined minimum speed. It can therefore be advantageous to calculate the changed speed value only when this is actually necessary. This can conserve hardware resources. In particular, computing capacity can be used for other purposes. The calculation of the changed speed value is only necessary, for example, if a future temporary standstill is requested and the current speed falls below a predetermined minimum speed. In other words, the changed speed value is calculated when the temporary standstill is imminent and the braking torque is to be controlled to ensure the temporary standstill of the vehicle.

[0030] A further aspect of the invention relates to a computing device for a vehicle assistance system, which is configured to carry out a method according to the invention. The computing device can be provided, for example, by at least one electronic control unit.

[0031] The invention also relates to an assistance system for a vehicle, comprising a computing device according to the invention. In particular, the assistance system can be configured for at least automated longitudinal guidance of the vehicle. For example, the assistance system can be configured for distance-based cruise control (ACC), in particular with a stop-and-go function. Alternatively or additionally, the assistance system can be configured to at least assume longitudinal guidance of the vehicle during maneuvers, for example, parking maneuvers.

[0032] A vehicle according to the invention comprises an assistance system according to the invention. The vehicle can be designed, in particular, as a passenger car.

[0033] A further aspect of the invention relates to a computer program comprising instructions which, when executed by a computing device, cause the computing device to execute a method according to the invention and the advantageous embodiments thereof. Furthermore, the invention relates to a computer-readable (storage) medium comprising instructions which, when executed by a computing device, cause the computing device to execute a method according to the invention and the advantageous embodiments thereof.

[0034] The preferred embodiments presented with reference to the method according to the invention and their advantages apply accordingly to the computing device according to the invention, to the assistance system according to the invention, to the vehicle according to the invention, to the computer program according to the invention and to the computer-readable (storage) medium according to the invention.

[0035] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0036] The invention will now be explained in more detail using preferred embodiments and with reference to the accompanying drawings. Fig. 1 is a schematic representation of a vehicle comprising a computing device for carrying out a method for controlling a braking torque of a vehicle, Fig. 2 the vehicle according to Fig. 1 while driving uphill in combination with following a vehicle in which another road user is in front of the vehicle, Fig. 3 according to the state of the art, among other things, a temporal progression of the speed of the vehicle according to Fig. 2, where a distance-based cruise control system slows the vehicle down to a standstill due to the other road user and the vehicle rolls back due to the gradient, and Fig. 4 among other things, a temporal progression of the speed analogous to Fig. 3, wherein the computing device controls the braking torque of the vehicle so as to prevent the vehicle from rolling back.

[0037] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0038] Fig. Figure 1 shows a schematic plan view of a vehicle 1, which is designed as a passenger car. The vehicle 1 comprises a computing device 2, which serves to control a braking torque of the vehicle 1 during an at least partially automated driving up an incline 7 and / or down a decline by means of an assistance system 3. Furthermore, the vehicle 1 or the assistance system 2 comprises a speed sensor 4, by means of which speed values ​​vx can be provided.

[0039] The assistance system 3 can, for example, be a distance-based cruise control system with a stop-and-go function. With the assistance system 3, the speed or longitudinal speed of the vehicle 1 can be controlled to a predetermined desired speed. Furthermore, the distance to a road user 8 traveling ahead can be controlled. With the assistance system 3, the speed can be reduced to a temporary standstill, for example, when the road user 8 traveling ahead brakes.

[0040] As soon as a future temporary standstill of the vehicle 1 is required, for example because another road user 8 ahead brakes, the computing device 2 can receive standstill data provided by the assistance system 3. Furthermore, the computing device 2 continuously receives the speed values ​​vx, which are provided, for example, by the speed sensor 4 of the vehicle 1. These speed values ​​vx describe the current speed of the vehicle 1 during a deceleration of the vehicle 1 before the temporary standstill.

[0041] Furthermore, the computing device 2 can continuously determine slope gradient data that describe an angle of the incline or decline of a roadway 7. The angle of the incline or decline can be determined, for example, based on data from an acceleration sensor (not shown here) and / or based on digital map data. The angle can be determined for the current position of the vehicle 1 and / or for an area of ​​the roadway 7 in which a standstill is expected to occur.

[0042] Based on the standstill data, the speed values ​​vx and the slope data, the computing device 2 can continuously calculate a changed speed value vx ge This changed speed value vx ge may depend on the speed value vx and the slope data. In addition, the changed speed value vx gedepend on the acceleration or deceleration of vehicle 1 before coming to a standstill. If the changed speed value vx ge a predetermined threshold value 14 and the standstill data are received by the computing device 2, the computing device 2 can output an electronic control signal 5 for controlling the braking torque to ensure the temporary standstill of the vehicle 1. The braking torque can be provided by the respective brakes 6 of the vehicle 1 and ensure the temporary standstill of the vehicle 1.

[0043] Fig. 2 shows the vehicle 1 according to Fig. 1 while driving on a roadway 7 with an incline in combination with following another road user 8 in front of the vehicle 1. The driver of the vehicle 1 can, for example, specify a desired speed. The assistance system 3 can automatically regulate the speed of the vehicle 1 while maintaining a minimum distance from the road user 8. If the other road user 8 in front decelerates, for example, the assistance system 3 reduces the speed of the vehicle 1 so that comfortable driving in convoy is possible for the driver of the vehicle 1. If the other road user 8 comes to a standstill, the assistance system 3 of the vehicle 1 can brake the vehicle 1 to a standstill.

[0044] Such a braking maneuver, i.e. the braking of vehicle 1 to a standstill, is usually carried out in such a way that stopping is as comfortable as possible for the driver of vehicle 1. In particular, the braking or stopping of vehicle 1 should not occur suddenly. To this end, for example, the braking torque of vehicle 1 can be reduced towards the end of the braking maneuver. If the speed of vehicle 1 falls below a threshold value 14, an additional braking torque is usually provided, which ensures the temporary standstill of vehicle 1. When driving uphill or downhill, it can happen that the temporary standstill of vehicle 1 occurs faster than the braking torque required to ensure the temporary standstill is applied to the brakes 6 of vehicle 1. As a result, vehicle 1 could roll backward briefly when driving uphill.

[0045] By means of the computing device 2, such behavior can be prevented by controlling the braking torque to ensure the stationary state of the vehicle 1. In other words, a comfortable braking maneuver is possible, while simultaneously ensuring the temporary standstill of the vehicle 1 on all slopes.

[0046] Fig. 3 shows, according to the state of the art, among other things, a temporal progression of the speed values ​​vx of the vehicle 1 according to Fig. 2, whereby the assistance system 3 brakes the vehicle 1 due to the other road user 8 ahead until it comes to a standstill and the vehicle 1 rolls back due to the gradient. In addition, Fig. 3 shows a time course of a wheel speed 10. Furthermore, Fig. 3 shows a time course of a target braking torque 11 and an actual braking torque 12. Finally, Fig. 3 a state 13, which is assigned to a dynamic journey, a state 13', which is assigned to a temporary standstill, and the threshold value 14.

[0047] It can be seen that the state change from state 13 or the dynamic driving state to state 13' or the temporary standstill state of the vehicle 1 according to the prior art occurs precisely when the temporal progression of the speed values ​​vx falls below the threshold value 14. However, due to the gradient of the roadway 7, the vehicle 1 rolls backwards briefly. This can be recognized from the temporal progression of the wheel speed 10. The temporal progression of the wheel speed 10 is negative during the rolling back. The temporal progression of the speed values ​​vx of the vehicle 1 represents the absolute value of the speed and is therefore positive during the rolling back, even though a temporary standstill is requested by the assistance system 3 of the vehicle 1.

[0048] Fig. 4 shows, among other things, a temporal progression of the speed values ​​vx analogous to Fig. 3, wherein the computing device 2 controls the braking torque of the vehicle 1 in such a way that the vehicle 1 is prevented from rolling back. For this purpose, the computing device 2 continuously calculates changed speed values ​​vx ge , the temporal course of which Fig. 4. The changed speed value vx ge is calculated here as soon as the speed value vx falls below a minimum speed 16. The changed speed value vx ge can be calculated continuously using the following formula: vxge=vx+ax*Δt.

[0049] Here, Δt describes an angle-dependent time element determined based on the slope data, and ax describes the acceleration of vehicle 1. The acceleration is negative because it represents a deceleration. Adding the vehicle acceleration ax multiplied by a gradient-dependent time delta Δt results in a speed lead, which increases with increasing deceleration or gradient.

[0050] As soon as the time course of the changed speed value vx ge falls below the threshold value 14, a state change from a dynamic driving state 13 to a temporary standstill state 13' can occur. The temporal progression of the changed speed value vx gefalls below the threshold value 14 earlier than the time course of the speed value vx. This can prevent the vehicle 1 from rolling back. This is evident from the fact that the time course of the wheel speed 10 is consistently positive. In particular, in comparison to Fig. 3 that the temporal progression of the target braking torque 11 and the actual braking torque 12 is brought forward. Thus, the braking torque for securing the temporary standstill 13 of the vehicle 1 is applied to the brakes 6 of the vehicle 1 precisely when the vehicle 1 comes to a standstill, or the assistance system 3, for example, a distance-based cruise control, has braked the vehicle.

[0051] The fact that the transition from a dynamic driving state to a temporary standstill of vehicle 1 is extremely comfortable for the driver of vehicle 1 can be seen in the slow and steady reduction in the speed of vehicle 1. In particular, the temporal progression of the speed continuously and evenly approaches a zero value.

Claims

[1] Method for controlling a braking torque of a vehicle (1) during an at least partially automated driving uphill and / or downhill by means of an assistance system (3), wherein the assistance system (3) is set up for the at least partially automated longitudinal guidance of the vehicle (1), comprising the steps: - Receiving standstill data as soon as a future temporary standstill of the vehicle (1) is requested by the assistance system (3) during the at least partially automated driving uphill and / or downhill, - Continuously receiving speed values ​​(vx) describing a speed of the vehicle (1) during a deceleration of the vehicle (1) before the temporary standstill, - Continuous determination of slope data that describe an angle of inclination or gradient, - Continuous calculation of a changed speed value (vx ge), which depends on the speed value (vx) and the slope data, - Output of an electronic control signal to control the braking torque to ensure the temporary standstill of the vehicle (1) as soon as the changed speed value (vx ge ) falls below a predetermined threshold value (14) and the standstill data are received, and - the changed speed value (vx ge ) is calculated in such a way that, in comparison to the speed value (vx), it falls below the predetermined threshold value (14) all the sooner the greater the angle of the incline or decline. [2] Method according to claim 1, characterized by that additional acceleration data describing an acceleration or deceleration of the vehicle (1) before the temporary standstill are received and / or determined and the changed speed value (vx ge) is additionally calculated based on the acceleration data. [3] Method according to claim 2, characterized by that the changed speed value (vx ge ) is calculated in such a way that, in comparison to the speed value (vx), the speed falls below the predetermined threshold value (14) all the sooner the greater the acceleration or deceleration of the vehicle (1). [4] Method according to one of the preceding claims, characterized by that the electronic control signal is output in such a way that the braking torque for ensuring the temporary standstill of the vehicle (1) is higher, the greater the acceleration or deceleration of the vehicle (1) is and / or the greater the angle of the incline or decline is. [5] Method according to one of the preceding claims, characterized bythat to determine the slope data describing the angle of the ascent or descent, data from an acceleration sensor and / or digital map data are received. [6] Method according to one of the preceding claims, characterized by that the calculation of the changed speed value (vx ge ) is carried out if the speed value (vx) falls below a predetermined minimum speed (16). [7] Computing device (2) for an assistance system (3) of a vehicle (1), wherein the computing device (2) is configured to carry out a method according to one of the preceding claims. [8] Assistance system (3) for a vehicle (1), comprising a computing device (2) according to claim 7, wherein the assistance system (3) is configured for at least partially automated longitudinal guidance of the vehicle (1).

Images