Method for operating a driver assistance system

Abstract

The invention relates to a method for operating a driver assistance system for longitudinal control of a motor vehicle, in which, during a vehicle journey, the actual vehicle speed is regulated to a target vehicle speed, wherein the driver assistance system has a setting unit for manually setting the target vehicle speed, and a speed unit for determining a speed setpoint on a road segment, in which, when the speed setpoint is changed, the old speed setpoint and the new speed setpoint are compared with the current target vehicle speed, if the current target vehicle speed was manually set by the setting unit, in which the new speed setpoint is automatically adopted as the new target vehicle speed.except when the current target vehicle speed is lower than both the old speed setpoint and the new speed setpoint, whereby, if a speed setpoint is determined and a target vehicle speed is manually set, a deviation between the manually set target vehicle speed and the speed setpoint is determined, the deviation is compared with a stored threshold value, and the detected speed setpoint is adopted as the target vehicle speed if the deviation is less than or equal to the threshold value.

Description

[0001] The invention relates to a method for operating a driver assistance system for longitudinal control of a motor vehicle. The invention further relates to a driver assistance system and software for carrying out the method.

[0002] Modern motor vehicles are regularly equipped with various driver assistance systems that support the driver. These systems primarily monitor and analyze the vehicle's surroundings to detect dangerous situations, especially collision risks, early on and to assist the driver with their maneuvers or prevent them altogether.

[0003] In this and the following, an Advanced Driver Assistance System (ADAS) refers specifically to a device in a motor vehicle that assists the driver while driving the vehicle. Such ADAS systems can be either purely informational systems that display supporting information to the driver (e.g., directional arrows on a screen / display) or driving systems that automatically influence the vehicle's movement (e.g., steering and / or acceleration).

[0004] Driver assistance systems for longitudinal guidance of the vehicle, such as adaptive distance or speed control (also called adaptive cruise control, ACC), control and / or regulate the actual vehicle speed to a target vehicle speed (setpoint, target speed) during a journey of the vehicle.

[0005] In particular, adaptive cruise control systems (ACC) use traffic sign recognition systems, such as camera sensors, and / or map data to determine speed limits during operation. Predictive adaptive cruise control (pACC) systems extend distance and speed control to include anticipatory information about the road ahead and / or sign recognition. Unlike a standard cruise control system, pACC also incorporates data about the route (e.g., curves, inclines or declines, speed limits) to determine the target speed, allowing for proactive and efficient speed adjustments. For example, such a predictive speed setting might use map data, sensors, and sign recognition to predict that a new speed limit will be in effect in 300 meters, enabling the driver assistance system to prepare for the appropriate speed in advance.

[0006] The determined or predicted speed limits are displayed to the driver and can optionally be adopted for vehicle control, for example, by adjusting the target vehicle speed (setpoint, set speed) for a longitudinal guidance assistance system. Here and in the following, a "speed limit" refers specifically to a speed restriction (speed limit), i.e., a predetermined maximum speed that a vehicle may not exceed on a specific section of road. This limit can be established by traffic signs, electronic displays, legal regulations, or based on a prediction.

[0007] Due to legal requirements or technical regulations for driver assistance systems, for example, in the future, if a current target vehicle speed is a target vehicle speed set by the driver before the change, the current target vehicle speed will not be automatically changed to the new speed set by the system if the target vehicle speed set by the driver is below both the previous system-determined speed set and the new system-determined speed set.

[0008] This could lead to the following situation in the future when predictive cruise control is activated: If the cruise control is activated in urban areas at less than 50 km / h (kilometers per hour), i.e., below the speed limit of 50 km / h, the predictive cruise control is not permitted to automatically increase the target vehicle speed for longitudinal guidance to 100 km / h at the edge of the urban area. However, if the cruise control is activated in urban areas at 50 km / h or higher, the predictive cruise control can automatically increase the target vehicle speed for longitudinal guidance to 100 km / h at the edge of the urban area. This means that deliberately reducing the target vehicle speed or activating the system below the permitted speed limit will prevent the target vehicle speed from increasing automatically, and thus the function will not operate as previously expected.

[0009] User interfaces in motor vehicles, such as a driver information display (DID) or input / function buttons on the steering wheel, are preferably designed to be as simple and clear as possible to reduce the complexity of operation and make interaction more intuitive. However, this simplification can result in the driver receiving less information about how the driver assistance function works, making it more difficult to understand the functional logic and use it correctly. In particular, a lack of feedback or insufficient guidance can lead to the driver inadequately learning how the driver assistance function works or misinterpreting it.

[0010] DE 10 2015 006 411 A1 discloses a method for operating a distance or speed control system for a motor vehicle, in which a first maximum speed value is detected and a set speed of the system is automatically adjusted depending on this maximum speed value. Furthermore, the first maximum speed value is adopted as the set speed, depending on a change in the set speed made manually by the driver and / or a driving speed of the vehicle.

[0011] US Patent 2018 / 0079411 A1 discloses a driver assistance control unit that calculates a speed deviation, which represents the difference between a target speed and a speed limit in a situation where the two values ​​differ. If the speed deviation is less than or equal to a threshold, the driver assistance control unit sets an acceptance prohibition flag to "1". If the speed deviation is greater than the threshold, the acceptance prohibition flag is set to "0". When the acceptance prohibition flag is set to "1", the driver assistance control unit interprets a long press of a control element not as an acceptance operation, but as an acceleration or deceleration operation.

[0012] The invention is based on the objective of providing a particularly suitable method for operating a driver assistance system for longitudinal control of a motor vehicle. In particular, the aim is to increase the probability that the driver assistance system is activated within a speed range or that it is configured in such a way that automatic acceptance of new, higher speed settings is possible, or that driver support is maximized. The invention is further based on the objective of providing a particularly suitable driver assistance system and particularly suitable software.

[0013] The problem is solved according to the invention with respect to the method by the features of claim 1, the driver assistance system by the features of claim 5, and the software by the features of claim 6. Advantageous embodiments and further developments are the subject of the dependent claims.

[0014] The advantages and features mentioned with regard to the process are also transferable, mutatis mutandis, to the driver assistance system and / or the software, and vice versa. Where process steps are described below, advantageous configurations for the driver assistance system and / or the software arise in particular from their ability to execute one or more of these process steps.

[0015] The conjunction “and / or” is to be understood here and in the following as meaning that the features linked by means of this conjunction can be both common and alternative to each other.

[0016] The method according to the invention is designed and configured for operating a driver assistance system. The driver assistance system is designed and configured for longitudinal control of a motor vehicle. In its active state, the driver assistance system regulates the actual vehicle speed to a target vehicle speed (setpoint, target speed, maximum speed) during a journey. According to the method, the driver assistance system is preferably implemented as an adaptive cruise control (ACC) or predictive adaptive cruise control (pACC), which dynamically adjusts the target vehicle speed, for example, to a speed limit.

[0017] The driver assistance system, for example, has an interface for the driver of the vehicle, through which the driver can interact with the vehicle assistance system. This interface is specifically designed as a human-machine interface (HMI), which has input and output devices through which the driver can transmit information to or receive information from the driver assistance system.

[0018] The interface, or HMI, features an input device for manually setting the target vehicle speed. The output device of the interface is, in particular, a (digital) display unit.

[0019] In this context, "manual setting of the target vehicle speed" refers specifically to a setting of the target vehicle speed initiated by the (motor vehicle) driver. This also includes activating the driver assistance system, where, for example, the current actual vehicle speed is adopted as the target vehicle speed.

[0020] The setting unit, for example, includes a control unit (operating or function keypad), such as one located on the steering wheel of a motor vehicle, which allows the target vehicle speed to be manually increased or decreased, for example, in increments. The control unit may have a number of buttons, for example, at least two, one for increasing the target vehicle speed (plus button) and one for decreasing it (minus button). Alternatively, instead of plus and minus buttons, the control unit may include scroll or slide elements for increasing and decreasing the target vehicle speed.Additionally or alternatively, the control unit may have a further (set) button, which is designed and configured to adopt a current actual vehicle speed value as the target vehicle speed for longitudinal control of the vehicle. The setting unit may also include a foot pedal or accelerator pedal as a control element. The foot pedal is, in particular, an accelerator or brake pedal, by means of which a target vehicle speed value can be set, which is above or below a current speed setting.

[0021] The driver assistance system also includes a speed unit for determining a speed limit on a road segment. The speed unit is designed and configured, for example, to detect a speed limit or a change in a current speed limit. For this purpose, the speed unit includes, for example, optical sensors (e.g., a camera), radar systems, or a navigation device to detect a speed limit or its change on a current road segment or route segment. The speed unit also includes, for example, a traffic sign recognition system for evaluating the sensor data. Preferably, the speed unit is designed for predictive speed limit determination.This means that the speed unit evaluates, for example, map data, topographic information or recognized traffic signs in order to proactively or predictively adjust the vehicle's speed to upcoming road layouts, speed limits or traffic situations.

[0022] During operation of the driver assistance system, the speed unit regularly or continuously determines the speed limit on a currently and / or future road segment. The speed unit thus, for example, records the speed limit on the currently driven road segment and / or predicts the speed limit on a future road segment.

[0023] When the speed limit changes, i.e., when the current speed limit changes from a previously set speed limit (old speed limit) to a newly set speed limit (new speed limit), the new and old speed limits are compared with the current target vehicle speed, provided the current target vehicle speed was manually set via the control unit. In other words, when the speed limit changes, the speed limits determined by the control unit are compared with the currently set target vehicle speed, if this was manually specified or set by the driver.

[0024] As per the procedure, the new speed setting is automatically adopted as the new target vehicle speed, unless the current target vehicle speed is lower than both the old speed setting and the new speed setting. Here and in the following, "adopting the speed setting as the target vehicle speed" means, in particular, that the specific (speed) value of the new speed setting is stored in memory and used as the new target vehicle speed. In other words, the current target vehicle speed is overwritten with the value of the new speed setting.

[0025] According to the invention, if a speed target is set and the desired vehicle speed is manually adjusted, a deviation between the manually adjusted desired vehicle speed and the speed target is determined in a first process step. In a subsequent second process step, the deviation is compared with a stored threshold value, and in a third process step, the detected speed target is adopted as the desired vehicle speed if the deviation is less than or equal to the threshold value.

[0026] In particular, the method implements a logic for the driver assistance system in which activation or (manual) setpoint adjustment within a threshold range defined by the threshold value around the speed setpoint causes the target vehicle speed to be automatically set to the speed setpoint.

[0027] The procedure thus uses the specified speed target as an attractor during the setpoint or target value adjustment, with the attraction range, within which the target vehicle speed is set (attracted) upon activation or adjustment to the speed target, being defined by the threshold value. For example, the threshold value is dimensioned such that it corresponds to a range of, say, 0.5% to 5% around the speed target. This can apply to both accelerating and decelerating speed target changes, or both together.

[0028] In other words, the target vehicle speed is set to the specified speed limit when the deviation of the set target vehicle speed from the speed limit falls within a tolerance range defined by the threshold. The deviation used here is, in particular, an absolute or relative deviation of the target vehicle speed from the specified speed limit. For a relative deviation, the quotient (e.g., in percent) of the difference between the speed limit and the target vehicle speed (dividend) is determined. For example, the target vehicle speed is set to the specified speed limit when the set target vehicle speed is within the speed range of speed limit ± 5%, and especially within the speed range of speed limit ± 0.5%, is located. .

[0029] According to the invention, mechanisms are integrated into the driver assistance system that increase the probability of activating the longitudinal control system within a speed range or manually adjusting it so that automatic adoption of new, higher speed limits is possible, or driver support is maximized. This provides a particularly suitable method for operating a driver assistance system.

[0030] According to the invention, if the deviation exceeds the threshold, an offer is generated for the driver, particularly in the form of a visual cue, to adjust the manually set target vehicle speed to the detected speed target. In other words, the driver is asked whether they wish to adjust their set target vehicle speed to the specified speed target. This is particularly advantageous for deviations towards lower vehicle speeds, i.e., when the target vehicle speed is lower than the specified speed target, allowing the driver to increase the target vehicle speed to the speed target if necessary, thus ensuring automatic takeover and acceleration when a future speed target is reached.

[0031] The driver is thus offered the option to adopt the newly detected or future speed limit if the target vehicle speed deviates from the specified speed limit by more than the threshold. For example, this offer could take the form of a visual notification indicating the detection or predicted change in the speed limit if the set target vehicle speed is outside the speed range for automatic adoption and the speed control unit has detected a new, higher speed limit or could predictively adjust it. This notification would include, for example, the new speed limit and instructions for the driver to use to adopt the new speed limit as the target vehicle speed.

[0032] An additional aspect of this system is that if the deviation exceeds the threshold, an (absolute or relative) speed deviation is calculated between the currently determined speed setting and the target vehicle speed (speed delta, speed offset). This speed deviation can be determined both as an absolute speed value in km / h (mph) and as a percentage deviation.

[0033] Subsequently, when a speed limit changes and the new limit is higher than the old one, a suggestion is generated and displayed to the driver. This suggestion allows the driver to adjust the manually set target vehicle speed to the detected speed limit minus the speed deviation. In other words, the suggestion to adopt the new, higher speed limit includes a negative (speed) offset, ensuring that the current speed difference is also applied to the new speed limit and the target vehicle speed set by the control system.

[0034] The display or output of the offer or takeover proposal, as well as any offered offset to the target vehicle speed during takeover, depends, for example, on a comparison of the speed differences and is only offered above or below a predefined minimum or maximum value. The minimum and / or maximum values ​​depend, for example, on the type of road (rural road, highway, etc.) and represent either a percentage or an absolute difference as an offset. For example, on a rural road, an offset of between 20 km / h and 3 km / h is considered for a takeover proposal, while on a highway, an offset of between 30 km / h and 5 km / h is considered.

[0035] Furthermore, it is conceivable, for example, to suspend the notification (offer, suggestion) to take over for certain driving situations (low charge level, high speeds) if it can be assumed that a conscious decision by the driver led to the lower speed.

[0036] In a possible further development, the procedure is extended in such a way that leaving the optimal range is prevented by making it more difficult to set or adjust the target vehicle speed. An "optimal range" here refers specifically to a speed range with respect to the specified speed target, within which automatic acceleration to a future specified speed is possible – i.e., a speed range greater than or equal to the currently specified speed target.

[0037] In this context, "difficult setting or adjustment" refers specifically to situations where manually setting the target vehicle speed is less than optimal compared to the optimal range. Preferably, a non-linear characteristic curve is stored for the adjustment unit, which modifies the manual adjustability of the target vehicle speed. In other words, the adjustability is modified by a control element based on this characteristic curve.

[0038] In one possible advanced training scenario, for example, when adjusting the vehicle speed via a keypad with plus and minus buttons or scroll / slide elements, the adjustment of the target vehicle speed via the keys is not linear, but rather follows a predefined characteristic curve, thus facilitating the setting of the target vehicle speed within the optimal range. An asymptotic characteristic curve is predefined for both keypad and accelerator pedal operation.

[0039] Furthermore, it is conceivable, for example, to provide a signal via an active accelerator pedal, such as haptic feedback. For instance, the accelerator pedal could vibrate or produce another haptic movement so that the driver perceives this feedback in their foot. Additionally or alternatively, it is possible to adjust the accelerator pedal response curve. This makes it easier to apply the pedal within the optimal range and more difficult to apply it within a less than optimal range.

[0040] In an advantageous embodiment, the driver assistance system includes a display unit for showing a visual indicator. The display unit is specifically designed as a driver information display (RID). Preferably, the display unit is part of the interface or the human-machine interface (HMI), and is used, in particular, as an output device for the interface. The display unit is designed and configured to provide the driver with vehicle-specific information visually. The display unit is, in particular, arranged within the driver's field of vision and is, for example, designed as a digital instrument cluster, a screen, an operating and display device (e.g., a touchscreen), or a head-up display. The display unit presents, for example, assistance system information or driving parameters.The display unit is designed and configured, for example, to show the current actual vehicle speed. Optionally, the display unit can also show a current speed setting and / or the target vehicle speed.

[0041] According to the training, a visual indication is displayed on the display unit, which shows a vehicle user whether the new speed limit is automatically adopted as the new target vehicle speed or not, if the new speed limit is greater than the current target vehicle speed.

[0042] The basis for this further training is therefore a functional logic which, by comparing the currently set target vehicle speed of the longitudinal control system with the permitted maximum speed for the road section (speed limit), checks whether an automatic adjustment of the target vehicle speed may be carried out in the event of a detected or predictive change in the permitted speed limit.

[0043] This improves the transparency and learnability of the system behavior for the driver, as it provides visual feedback as to whether a possible predictive or detected change in speed setting in an accelerating direction is adopted by the control system or not.

[0044] In a preferred training setting, a speed window is displayed as a visual indicator, within which the new speed setting can be automatically adopted as the new target vehicle speed. In other words, the indicator shows the speed range or window in which the driver receives maximum support from the control system.

[0045] The visual indicator is implemented, for example, by dynamically displaying the speed range within which automatic speed adjustment can or will occur. This visual indicator is integrated into existing display elements of the instrument cluster. Specifically, the visual indicator is integrated into the speedometer ring. This allows the driver to visually check whether a new, higher speed setting will be automatically applied at the current speed. Additionally, this speedometer ring integration could be linked to an indicator that displays the system activation status, including the current target vehicle speed setting (e.g., via the accelerator pedal). Alternatively, or in addition, the necessary speed range that still needs to be "overcome" before the optimal speed range is reached can be displayed.

[0046] Alternatively, the visual indicator can be displayed separately, independent of other display elements on the display unit. For example, the visual indicator could be an icon or an indicator showing whether a new, higher speed setting can be automatically adopted. It is also possible to differentiate the display of the target vehicle speed set by the control system. For instance, the target vehicle speed could be represented by different colors or sizes, depending on whether the target vehicle speed is within the optimal range or not.

[0047] The driver assistance system according to the invention is designed, suitable, and configured for longitudinal guidance of a motor vehicle. During operation, the driver assistance system regulates the actual vehicle speed to a target vehicle speed. The driver assistance system is specifically designed as an adaptive cruise control (ACC), preferably as a predictive adaptive cruise control (pACC).

[0048] The driver assistance system includes a setting unit for manually adjusting a target vehicle speed. The driver assistance system also includes a speed unit for determining (detecting, predicting) a speed limit on a current and / or future road segment.

[0049] The driver assistance system also includes a controller (i.e., a control unit) which is linked to the setting unit and the speed unit via signals. The controller is further connected, for example, to a speed sensor to measure the vehicle's current speed. This results in a particularly effective driver assistance system.

[0050] The controller is generally configured – in terms of programming and / or circuitry – to carry out the method described above according to the invention. Specifically, the controller is configured to determine, when a speed target is set and the desired vehicle speed is manually adjusted, a deviation between the manually adjusted desired vehicle speed and the speed target is determined, the deviation is compared with a stored threshold value, and the detected speed target is adopted as the desired vehicle speed if the deviation is less than or equal to the threshold value.

[0051] In a preferred embodiment, the controller is formed, at least in its core, by a microcontroller comprising a processor and a data memory. The functionality for carrying out the method according to the invention is implemented programmatically in the form of operating software (firmware), so that the method—optionally in interaction with a driver—is carried out automatically when the operating software is executed in the microcontroller. Alternatively, within the scope of the invention, the controller can also be formed by a non-programmable electronic component, such as an application-specific integrated circuit (ASIC) or an FPGA (field-programmable gate array), in which the functionality for carrying out the method according to the invention is implemented by circuitry.

[0052] An additional aspect of the invention provides for software on a medium or data carrier for carrying out the method described above. This means that the software is stored on a data carrier and is designed and configured for carrying out the method described above. The software comprises commands which, when executed by a computer (in particular by the controller of the driver assistance system), cause the computer to execute the method according to the invention. This results in particularly suitable software for operating a driver assistance system for the longitudinal guidance of a motor vehicle, with which the functionality for carrying out the method according to the invention is implemented programmatically. The software is thus, in particular, operating software (firmware), with the data carrier being, for example, a data storage device of the controller.

[0053] The invention is explained in more detail below with reference to a drawing, which shows simplified and schematic representations of: Fig. 1 a motor vehicle with a driver assistance system for longitudinal guidance, Fig. 2 an input unit of the driver assistance system, Fig. 3 a display unit of the driver assistance system with a visual indicator, Fig. 4. A flowchart for a procedure for operating the driver assistance system, Fig. 5 a procedural logic for adopting a specific speed requirement, and Fig. 6 a procedural logic for setting a target vehicle speed.

[0054] Corresponding parts and sizes are always marked with the same reference symbols in all figures.

[0055] The Fig. Figure 1 shows a top view of a motor vehicle 2 with a driver assistance system 4 for longitudinal guidance of the motor vehicle 2. The driver assistance system 4 is designed in particular as an adaptive cruise control.

[0056] The driver assistance system 4 has a speed unit 6 for determining a speed setpoint 8 on a road section, an interface 10 for the (vehicle) driver of the motor vehicle 2 and a controller 12.

[0057] During operation of the driver assistance system 4, the controller 12 regulates an actual vehicle speed I ( Fig. 3) to a target vehicle speed S ( Fig. 3) The controller 12 is connected to the speed unit 6 and the interface 10 via a signal connection. The controller 12 has a memory in which the target vehicle speed S is stored. The controller 12 is also connected to a speed sensor (not shown) for detecting the current actual vehicle speed I. The controller 12 is additionally connected to a longitudinal control unit of the vehicle 2 to regulate the detected actual vehicle speed I to the target vehicle speed S.

[0058] The in Fig. The speed unit 6 shown, for example, is designed and configured to record a speed limit 8 or a change to a current speed limit 8 on a current road segment or (driving) route segment. In the Fig. 1. The speed limit 8 is implemented, for example, as a traffic sign with a speed limit. The speed unit 6 is implemented, in particular, as an optical sensor, specifically a camera. Additionally or alternatively, the speed unit 6 is configured for the predictive determination of the speed limit 8. This means that, for example, map data, topographic information, or recognized traffic signs are evaluated by the speed unit 6 to determine a future or imminent speed limit 8.

[0059] During operation of the driver assistance system 4, the speed unit 6 regularly or continuously determines the speed setting 8 on a currently and / or future road segment. The speed unit 6 thus, for example, detects the speed setting 8 on the currently driven road segment and / or predicts the speed setting 8 on a future road segment.

[0060] Interface 10 is specifically designed as an HMI, which includes a setting unit 14 with a button unit 16 and a foot pedal 18, as well as a display unit 20. The button unit 16 is, for example, a number of function buttons arranged on the steering wheel, and in the Fig. The control panel (operating element panel) is shown in Figure 2. In an alternative embodiment not shown in detail, the setting unit 14 features, in particular, scroll and / or slide elements as functional elements.

[0061] The setting unit 14 is designed and equipped to manually set or change the value for the target vehicle speed S using the keypad unit 16 and / or the foot pedal 18.

[0062] This is also in Fig. The foot pedal 18 shown in Figure 2 is specifically designed as an accelerator pedal. The foot pedal 18 is specifically designed to influence the actual vehicle speed I. The foot pedal 18 is also designed and configured to manually set a value for the target vehicle speed S.

[0063] Keypad 16 has a button 22 for setting a distance or time gap to a vehicle ahead and a button 24 for deactivating the driver assistance system 4. The keypad of key unit 16 also has three buttons 26, 28, and 30, with button 30 being used to activate the driver assistance system 4. Buttons 22 to 30 of the keypad are arranged, for example, in a plus or cross shape, with button 22 in the center, button 24 on the right, button 28 at the bottom, button 30 on the left, and button 26 at the top.

[0064] Keypad unit 16 is designed, suitable, and configured for manually setting the target vehicle speed S. The in Fig. The keypad unit 16 shown in this version has three keys 26, 28, 30 for manually setting or changing the target vehicle speed S. Key 26 is designed and configured to increase the currently set value of the target vehicle speed S, particularly incrementally, when pressed. Key 28 is designed and configured to decrease the currently set value of the target vehicle speed S, particularly incrementally, when pressed. Key 30 is optionally also designed and configured to adopt the current value of the actual vehicle speed I as the value for the target vehicle speed S when pressed.

[0065] The setting or changing of the target vehicle speed S using buttons 26 and 28 is preferably done along a non-linear, predefined characteristic curve, which facilitates setting the target vehicle speed within an optimal range. The characteristic curve shifts dynamically with the current target vehicle speed S. For example, the step size is reduced when manually setting the speed near the target speed. For instance, the step size is reduced within ±5% of the speed target 8, from, say, 5 km / h to 1 km / h.

[0066] The display unit 20 is designed, in particular, as a driver information display. The display unit 20 is arranged, in particular, within the driver's field of vision and is, for example, designed as a digital instrument cluster. In the embodiment shown, the display unit has a digital display window 32 for the driver assistance system 4.

[0067] Display window 32 contains a display element 34, which shows the activity status (on / off) of the driver assistance system 4. Display window 32 also includes a display element 36 for showing the detected actual vehicle speed I, a display element 38 for showing the currently set target vehicle speed S, and a display element 40 for showing a currently detected speed target 8.

[0068] The display elements 34 to 40 are preferably displayed when the driver assistance system 4 is switched on or activated, for example by pressing button 22 or by means of the foot pedal 18, wherein the display of the display elements 34 to 40 is ended by pressing button 24 when the driver assistance system 4 is switched off or deactivated.

[0069] The display window 32 still has a display element in the form of an optical indicator H1.

[0070] The display unit 20 also has, for example, a display element 41 in the form of a speedometer ring for displaying the actual vehicle speed I, whereby, for example, a further optical indication H2 can be displayed in the area of ​​the display element 41 if required.

[0071] The following is based on the Fig. 4 to Fig. Section 6 explains in more detail a method for operating the driver assistance system 4. This method is implemented, for example, by software implemented on the controller 12.

[0072] The procedure is started by activating the driver assistance system 4 in a process step 42. This starts a control logic 44, by means of which the adaptive speed control of the actual vehicle speed I to the target vehicle speed S is carried out. When the driver assistance system 4 is activated, for example, the current actual vehicle speed I is used as the initial target vehicle speed S, whereby a speed setpoint 8 is determined based on the speed unit 6.

[0073] As part of the control logic 44, process step 46 monitors whether a manual setting or change of the target vehicle speed S is made using the setting unit 14. Furthermore, process step 48 checks whether the speed unit 6 determines (detects, predicts) a new speed setpoint 8 or a change to the applicable (old) speed setpoint 8. Process steps 46 and 48 can be carried out in parallel or sequentially within the framework of the control logic 44.

[0074] If no manual setting or change of the target vehicle speed S is detected in process step 46, the control logic 44 continues unaffected. Similarly, the control logic 44 also continues unaffected if the speed setpoint 8 does not change as a result of process step 48.

[0075] In process step 46, a manual setting or change of the target vehicle speed S is performed. ein If detected, a rule logic 50 is used to set or store the new target vehicle speed S. neu started, which is then stored and used as the target vehicle speed S for the control logic 44 of the speed control.

[0076] In the course of the Fig. In the control logic 50 shown, a deviation A between the currently determined speed setpoint 8 and the newly set target vehicle speed S is first determined in a process step 52. ein Determined. Here, deviation A is defined in particular as a relative deviation from the manually set target vehicle speed S. ein used for the currently determined speed limit 8, i.e., the quotient (e.g., in percent) of the difference between the speed limit 8 and the target vehicle speed S. ein(Dividend) to the speed specification 8 (Divisor).

[0077] In a subsequent process step 54, the deviation A is compared with a stored threshold value.

[0078] In the case of a comparison result where the deviation A is less than or equal to the stored threshold value, the currently determined speed specification 8 is used as the new value for the target vehicle speed S in a process step 56. neu In other words, the manually set value for the target vehicle speed S is used in this case. ein The previous value was discarded and overwritten by the value of the specified speed 8. The specified speed 8 is therefore now the new target vehicle speed S. neu adopted for rule logic 44.

[0079] The procedural steps 52, 54, and 56 of the control logic 50 thus implement a logic in which a (manual) setpoint adjustment within a threshold-defined range around the speed setpoint 8 causes the target vehicle speed S to be automatically set to the speed setpoint 8. The specified speed setpoint 8 therefore acts as an attractor during the setpoint or set value adjustment, whereby the attraction range in which the target vehicle speed S ein The speed is set (increased) to the speed target 8, which is defined by the threshold value in process step 54. For example, the threshold value is dimensioned such that it corresponds to a range of, for example, 0.5% to 5% around the speed target 8.

[0080] If the comparison result shows that the deviation A is greater than the stored threshold value, an offer for the driver, specifically in the form of the visual indicator H1, is generated in process step 58 after process step 54 and displayed by means of the display unit 20. In a subsequent process step 60, it is monitored whether an input is made by the setting unit 14, specifically by the keypad 16, following the visual indicator H1. If, for example, the driver presses key 30 while indicator H1 is displayed, the specified speed setting 8 is set as the new target vehicle speed S. neu If the driver does not accept the speed setting 8, the manually set target vehicle speed S will be used. ein as new target vehicle speed S neu Used for rule logic 44.

[0081] Procedure steps 58 and 60 of the control logic 50 ask the driver whether he has set the target vehicle speed S. ein The driver is offered the option to adopt the specified speed 8 if the manually set target vehicle speed S is not reached. ein by more than the threshold value from the specified speed limit 8. This is particularly advantageous for deviations A that result in lower vehicle speeds, i.e., when the target vehicle speed S einis smaller than the specified speed target 8, so that the driver can increase the target vehicle speed S to the specified speed target 8 if necessary, in order to ensure that an automatic takeover and acceleration is possible by means of a control logic 62 for taking over the specified speed target 8 in the future.

[0082] If a change in the specified speed limit 8 is detected in process step 48, the control logic 62 is used to adopt the specified speed limit 8 as the new target vehicle speed S. neu started, which is then stored and used as the target vehicle speed S for the control logic 44 of the speed control.

[0083] In the course of the Fig. In the control logic 62 shown in step 64, it is first checked whether the currently stored value of the target vehicle speed S was set manually by the driver, or whether it was set automatically, for example by means of the control logic 62.

[0084] If the current target vehicle speed S has not been set due to a manual setting by the driver, then in a procedure step 66 the newly determined speed target 8 is used as the new value for the target vehicle speed S. neu In other words, the target vehicle speed S is automatically overwritten with the newly determined speed setpoint 8. The specified speed setpoint 8 is therefore set as the new target vehicle speed S. neu adopted for rule logic 44.

[0085] If the current target vehicle speed S has been set by the setting unit 14, the current target vehicle speed S is compared with the old speed setting 8 and with the new speed setting 8 in a process step 68. In other words, if the speed setting is changed, the speed settings 8 determined by the speed unit 6 are compared with the currently set target vehicle speed S, if this was manually set or adjusted by the driver.

[0086] Subsequently, depending on the comparison result, in a process step 70 the optical indicator H2 is displayed, which informs the driver whether the newly determined speed setting 8 will automatically be used as the new target vehicle speed S. neu will be taken over or not.

[0087] The new speed specification 8 is automatically converted into the new target vehicle speed S in process step 66. neu The target vehicle speed S is adopted unless the current target vehicle speed S is lower than both the old speed setpoint 8 and the newly determined speed setpoint 8. In particular, the warning H2 is displayed if the target vehicle speed S is not within the speed range for automatic adoption and the speed unit 6 has detected a new, higher speed setpoint 8 or could predictively adjust it.

[0088] Procedure steps 64 and 68 implement a functional logic for the control logic 62, which checks, by comparing the currently set target vehicle speed S of the control logic 44 with the permitted maximum speed for the road segment (speed limit), whether an automatic adjustment of the target vehicle speed S may be carried out in the event of a detected or predictive change in the permitted speed limit 8. The indicator H2 serves as visual feedback for the driver, indicating whether a possible predictive or detected speed limit change in the direction of acceleration will be adopted by the control system or not.

[0089] In the Fig.In the embodiment shown in Figure 3, for example, a speed window above the speedometer ring 41 is displayed as an optical indicator H2, in which the new speed setting 8 is automatically adopted as the new target vehicle speed S. neu This is possible. In other words, the indicator H2 shows the speed range or speed window in which the driver receives maximum support from the driver assistance system 4.

[0090] If, in process step 68, it is determined that the conditions for the automatic adoption of the newly determined speed target 8 are not met, i.e., if the manually set target vehicle speed S is lower than both the new and the old determined speed target 8, then, following process step 70, a notification is generated for the driver in process step 72, specifically in the form of the visual indicator H1, and displayed by means of the display unit 20. In a subsequent process step 74, it is monitored whether any input is made by the setting unit 14, specifically by the keypad 16, after the visual indicator H1 has been displayed. If, for example, the driver presses key 30 while indicator H1 is displayed, the determined speed target 8 is set as the new target vehicle speed S. neuIf the driver does not accept the speed requirement 8, the previously applicable target vehicle speed S remains unchanged as the new target vehicle speed S. neu Used for rule logic 44.

[0091] The procedure incorporates 50 mechanisms through the control logic, which increase the probability that the target vehicle speed S for control logic 40 is set or adjusted in such a way that a new, higher speed limit can be automatically adopted by control logic 62, thereby maximizing driver support through the driver assistance system 4. Furthermore, indicator H2 provides the driver with visual information as to whether such an automatic adoption occurs or whether the driver must intervene by performing an additional action to adjust the target vehicle speed S when the speed limit 8 changes.

[0092] The control logics 50 and 62 can also be nested within each other. For example, in an additional or alternative implementation of control logic 50 (not shown in detail), it is provided that if the comparison result shows a deviation A greater than the stored threshold, the driver is given a visual suggestion to adopt the new, higher speed target 8 minus the deviation A, provided the target vehicle speed S was lower than the old speed target 8.

[0093] Furthermore, it is conceivable, for example, to suspend the notification (offer, suggestion) to accept the service for certain driving situations (low charge level, high speeds) if it can be assumed that a conscious decision by the driver has led to the lower target vehicle speed S.

[0094] The claimed invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived by a person skilled in the art within the scope of the disclosed claims without departing from the subject matter of the claimed invention. In particular, all individual features described in connection with the various embodiments can also be combined in other ways within the scope of the disclosed claims without departing from the subject matter of the claimed invention. Reference symbol list 2 motor vehicles 4 Driver assistance systems 6 speed unit 8 Speed ​​setting 10 Interface 12 controllers 14 Setting unit 16-key unit 18 Foot pedal 20 display units 22, ..., 30 key 32 display windows 34, ..., 41 Display element 42nd process step 44 Rule Logic 46, 48 Procedure step 50 Rule Logic 52, ..., 60 Procedure step 62 Rule Logic 64, ..., 70 Procedure step 72nd process step I Actual vehicle speed Target vehicle speed S ein set target vehicle speed S neu new target vehicle speed H1, H2 Note A deviation

Claims

[1] Method for operating a driver assistance system (4) for longitudinal guidance of a motor vehicle (2), in which, during a vehicle journey, an actual vehicle speed (I) is regulated to a target vehicle speed (S), wherein the driver assistance system (4) has an adjustment unit (14) for manually setting the target vehicle speed (S) ein ), and has a speed unit (6) for determining a speed requirement (8) on a road section, - in which, when the speed setting (8) is changed, the old speed setting (8) and the new speed setting (8) are compared with the current target vehicle speed (S), if the current target vehicle speed (S) has been manually set by the setting unit (14), - where the new speed setting (8) is automatically adopted as the new target vehicle speed (S neu) is adopted, unless the current target vehicle speed (S) is less than the old speed target (8) and less than the new speed target (8), characterized by , that if a speed target (8) is determined and a target vehicle speed (S) is set manually a) a deviation (A) between the manually set target vehicle speed (S ein ) and the speed requirement (8) is determined, b) the deviation (A) is compared with a stored threshold value, c) the recorded speed specification (8) as the target vehicle speed (S neu ) is accepted if the deviation (A) is less than or equal to the threshold, and d) if the deviation (A) is greater than the threshold, an offer is generated for a driver to reach the manually set target vehicle speed (S). ein) to set the recorded speed limit (8).. [2] Method according to claim 1, characterized by , that a non-linear characteristic curve is stored for the setting unit (14), by means of which the manual adjustability of the target vehicle speed (S) ein ) is modified. [3] Method according to claim 1 or 2, wherein the driver assistance system (4) has a display unit (20) for displaying an optical indicator (H1, H2), characterized by , that an optical indication (H2) is displayed on the display unit (20), which indicates to a vehicle user whether the new speed setting (8) is automatically adopted as the new target vehicle speed (S neu ) is adopted or not, if the new speed requirement (8) is greater than the current target vehicle speed (S). [4] Method according to claim 3, characterized by, that as a visual indicator (H2) a speed window is displayed in which an automatic adoption of the new speed setting (8) as the new target vehicle speed (S neu ) is possible. [5] Driver assistance system (4) for longitudinal guidance of a motor vehicle (2) which, during a vehicle journey, regulates an actual vehicle speed (I) to a target vehicle speed (S). - an adjustment unit (14) for manually setting a target vehicle speed (S ein ), - a speed unit (6) for determining a speed requirement (8) on a road section, and - a controller (12) for carrying out a method according to any one of claims 1 to 4. [6] Software on a data carrier for carrying out a method according to any one of claims 1 to 4, when the software runs on a computer.

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