Method and vehicle system for avoiding under-braking during simultaneous manual and automated longitudinal control, and correspondingly designed motor vehicle

Abstract

The invention relates to a method (11) for controlling a motor vehicle (1) which can be longitudinally controlled by a driver (2) and by a driver assistance system (3). If manual actuation of the brake operating element (5) is detected while the driver assistance system (3) is simultaneously requesting a positive driver-assistance-system target acceleration, a driver-assistance-system torque set by actuators at the time of initial detection of this actuation of the brake operating element (5) in order to implement the driver-assistance-system target acceleration is frozen. The torque that would be set by actuators in the current driving situation without propulsive longitudinal-control intervention by the driver assistance system (3) and without manual longitudinal-control intervention by the driver (2) is determined. If the torque thus determined is lower than the frozen driver-assistance-system torque, the frozen driver-assistance-system torque is then reduced to the determined torque. The invention also relates to a vehicle system (7) for carrying out the method, and to a motor vehicle (1) equipped therewith.

Description

[0001] 24-1744

[0002] 1

[0003] Method and vehicle system for underbraking prevention with simultaneous manual and automated longitudinal control and appropriately equipped motor vehicle

[0004] The present invention lies in the field of automotive engineering and relates to a method for controlling a motor vehicle that can be longitudinally guided, i.e., controlled, both manually by a driver and at least assisted or at least partially automated by a driver assistance system. The invention also relates to a vehicle system configured for the method and a motor vehicle equipped therewith.

[0005] Modern motor vehicles are increasingly equipped with functions and systems to improve user comfort or automate vehicle operation. This also increases complexity and, at least potentially, the susceptibility to errors or the risk of undesirable effects or behaviors in the respective vehicle. For example, it could happen that both the driver and a driver assistance system simultaneously attempt to intervene in longitudinal control. This would mean two independent controllers would be active at the same time, potentially interfering with or influencing each other, or even working against each other. Precise and consistent control would no longer be possible for the driver.If, for example, the driver assistance system or its influence on longitudinal control were deactivated during a longitudinal control intervention by the driver, the vehicle's behavior could change unpredictably and abruptly, and might even temporarily contradict the driver's intention. In principle, the simultaneously active influence of the driver assistance system on longitudinal control could also be kept constant during a longitudinal control intervention by the driver, um24-1744.

[0006] 2

[0007] to avoid unpredictable changes in the vehicle's behavior. However, this too can lead to problems, at least in certain situations. For example, if the driver presses the brake pedal while the driver assistance system simultaneously initiates positive acceleration, the vehicle may continue to accelerate, thus increasing its speed, despite the driver's braking intervention and the resulting activation of the brake lights. This can contradict the driver's intention and confuse or unsettle other road users. Therefore, further development and improvements are needed to ensure correct and situationally appropriate vehicle behavior in various circumstances.

[0008] As one approach, DE 102015012377 A1 describes a method for adjusting brake pressures on pneumatically actuated wheel brakes of a motor vehicle. In normal operating mode, a brake pressure is set depending on a driver's braking request. During an external braking request independent of the driver's braking request, a resulting brake pressure can be applied to the respective wheel brakes in a pressure control mode, taking into account both the external braking request and the driver's braking request. The pressure control mode is designed to end after the external operating request is withdrawn, based on a comparison of a value representing the driver's braking request with a predefined threshold. This is intended to ensure continuous braking behavior after the external braking request is withdrawn when the brake pressure is set in the pressure control mode.

[0009] German patent DE 602 18294 T2 describes a driver assistance system for a motor vehicle equipped with an electrically controlled brake actuation device. This system allows the vehicle's speed and longitudinal acceleration to be controlled based on the distance between the vehicle and an obstacle in front of it. The system allows the driver to deactivate the automated longitudinal control function when the brake pedal is pressed, thereby reactivating manual control. Conversely, manual operation of the accelerator pedal by the driver allows a preset reference speed for the automated longitudinal control to be exceeded without deactivating the automated longitudinal control function. 24-1744

[0010] 3

[0011] Another aspect that can add complexity to vehicle control is recuperation, i.e., the regenerative operation of a vehicle's electric drive motor while driving to generate electrical energy, particularly for charging a traction battery. EP 2371 647 B1, for example, addresses this. It describes the control of a motor vehicle's energy recovery system for recuperating kinetic energy using an electromechanical converter. This involves providing a target acceleration for the vehicle and information about the road gradient at the vehicle's location. Based on this, a quantitative measure of recuperation is determined, and the energy recovery system is controlled accordingly.

[0012] However, even with the existing approaches, in certain situations or constellations, suboptimal vehicle behavior may occur, or an ultimately unnecessarily complex implementation may be required.

[0013] The object of the present invention is to enable comfortable and safe vehicle operation in a simple, efficient and robust manner with simultaneous longitudinal guidance interventions by a driver assistance system and a driver.

[0014] This problem is solved by the subject matter of the main claim and the dependent claims or independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims.

[0015] The method according to the invention can be used for or in the control of a motor vehicle that is designed for manual longitudinal control by a driver, in particular in a manual operating mode, and for at least assisted or at least partially automated longitudinal control by a driver assistance system, for example 24-1744

[0016] 4

[0017] The system is set up in an at least assisted or at least partially automated operating mode, which is referred to here as the automated operating mode. The method can be applied automatically during operation of the motor vehicle, for example, continuously, intermittently, or only in a corresponding operating or control mode. In the method according to the invention, continuous monitoring of the current driving situation is performed, as well as continuous monitoring of target accelerations requested by the driver assistance system and of manual, i.e., in particular, driver-operated, actuations of a brake control element of the motor vehicle. Likewise, for example, corresponding continuous monitoring of manual actuations of an acceleration control element can be performed.

[0018] A brake control element can be, in particular, a brake pedal. An acceleration control element can be, in particular, an accelerator or foot pedal. It is therefore possible to monitor whether the driver of the motor vehicle is manually operating the brake control element – ​​and / or the acceleration control element. Such manual operation can indicate a driver request or a driver request moment, whereby the driver request moment depends on the strength, i.e., the extent or degree, of the operation. The operation of the brake control element can, individually, indicate a specific brake pedal request moment, which can be zero without brake pedal operation and increase in magnitude with increasing brake pedal operation.Similarly, an actuation of the acceleration control can, individually considered, indicate a specific desired accelerator pedal torque, which may be zero without actuation of the acceleration control and may increase in magnitude with increasing actuation of the acceleration control.

[0019] A foot point torque can also be specified. Such a foot point torque can also be different from zero even without the driver operating a control element, i.e., without manual longitudinal guidance intervention and in the foot point or zero / rest position of the respective control element. For example, such a foot point torque or offset torque can be a creep torque or a recuperation torque. A creep torque can be a positive, i.e., driving torque. A recuperation torque, on the other hand, can be a negative, i.e., braking or decelerating torque, meaning in the direction of stopping or bringing the vehicle to a standstill.

[0020] 5

[0021] The torque acting on the motor vehicle is the sum or balance of the pedal input torque and the foot input torque(s), resulting in a driver input torque that can be positive or negative depending on the situation. If the driver input torque is negative, it can also be referred to as the driver input braking torque.

[0022] In this context, "torque" refers to torques that can be applied, or generated, by means of a corresponding braking and / or drive system of the motor vehicle, or by means of a corresponding actuator. Such an actuator for applying a braking torque, i.e., a negative, decelerating torque, could be, for example, a hydraulic friction brake. Likewise, a braking torque can be applied, if necessary, by means of an electric drive motor. Such an electric drive motor can also serve as an actuator for applying drive torques, i.e., positive torques. The braking and / or drive system could, for example, include an actuator control unit for controlling one or more corresponding actuators and / or one or more corresponding actuators.

[0023] The fact that the driver assistance system requests a specific target acceleration can mean that, for at least assisted or at least partially automated longitudinal control, or to execute a specific driving maneuver, the system calculates a specific target acceleration for the vehicle and then outputs a corresponding control or request signal, for example, to a corresponding actuator to implement the request by applying a corresponding torque, or to a corresponding actuator control unit, such as, depending on the situation, a brake and / or drive control unit of the vehicle, or the like. The target acceleration requested by the driver assistance system can also be referred to here as the driver assistance system target acceleration (FAS:

[0024] Driver assistance system). Target accelerations for the driver assistance system (DAS) can be positive or negative in this context. Positive target accelerations, which increase the vehicle's speed relative to its surroundings, can be referred to as accelerating target accelerations. Negative target accelerations, which decrease the vehicle's speed relative to its surroundings, can be referred to as decelerating target accelerations. To implement, i.e., realize, a specific DAS-24-1744

[0025] 6

[0026] The target acceleration can be achieved by means of one or more actuators of the motor vehicle by means of a corresponding torque or a corresponding proportion of a set total torque, whereby this torque or proportion is referred to here as FAS torque.

[0027] The current driving situation can at least be characterized or determined by the speed of the motor vehicle and / or the acceleration of the motor vehicle (positive or negative) and / or the direction of travel of the motor vehicle and / or the local slope of the road (positive or negative).

[0028] The gradient of the surface and / or a recuperation level set in the vehicle. A set recuperation level can, for example, be or specify a degree or intensity of recuperation or a maximum recuperation power.

[0029] For example, the recuperation level can be set manually, i.e., in particular by the driver, or by a driver assistance system or function. Likewise, other variables or parameters can be considered to characterize or determine the driving situation, especially those variables or parameters that can influence the torque to be applied without manual longitudinal control inputs from the driver and at least without driving longitudinal control inputs from a driver assistance system.

[0030] In the method according to the invention, it is checked whether, during or when a manual actuation of the brake control element is detected, the driver assistance system, a cruise control, or a driver assistance function of the driver assistance system simultaneously requests a positive target acceleration. If this is the case, a driver assistance torque that was initially set by the driver control element upon initial detection of this actuation is automatically frozen, i.e., for example, by means of the drive system or a corresponding actuator, to implement the requested target acceleration. This means it is fixed or held constant until further notice. Accordingly, the driver assistance system or the driver assistance function responsible for the frozen driver assistance torque can then no longer actively or freely influence the driver assistance torque.For example, a corresponding parameter value specifying the frozen FAS torque can be frozen, i.e., fixed, in the drive system or a corresponding actuator control unit. Further control signals can then be stored there, for example.

[0031] 7

[0032] or requests from the driver assistance system, or at least those control signals or requests from the driver assistance system that would lead to an increase in the driver assistance system torque, are ignored or rejected. Similarly, to freeze the driver assistance system torque, the target acceleration requested by the driver assistance system can be frozen, i.e., fixed. This can be achieved, for example, by freezing the corresponding speed controller, i.e., continuously resetting or stopping / interrupting it, or by forcing an output value of the speed controller or the control or request signal issued by the driver assistance system that specifies the requested target acceleration, i.e., keeping it constant.

[0033] In a further step of the inventive method, the torque that would be actuated in the current driving situation, or in a corresponding driving situation, without any driving longitudinal control intervention from the driver assistance system (i.e., without a requested driving or positive target acceleration from the driver assistance system) and without any manual longitudinal control intervention by the driver is determined. This allows the determination of the torque that would be actuated in the current or a corresponding driving situation, for example, in purely manual operating mode without manual control element or pedal operation. Therefore, any current longitudinal control intervention by the driver assistance system, or a driving assistance function of the driver assistance system, which can generate positive, i.e., driving, torques from the driver assistance system even outside of a near-standstill speed range, can be disregarded.Such driver assistance functions can also be referred to here as drive assistance functions. Such a driving or...

[0034] Driving assistance functions can include, for example, ACC, i.e., adaptive cruise control.

[0035] However, creep and recuperation functions, i.e., corresponding creep and / or recuperation torques, can be taken into account and thus included in the torque determined here, since these functions are or can be active even in purely manual operating mode. Creep and / or recuperation functions can, unlike ACC, be configured to only generate or vary negative FAS torques, at least outside the near-standstill speed range. Such driver assistance functions can also be referred to here as deceleration assistance functions. Such a 24-1744

[0036] 8

[0037] A deceleration assist function can be a driver assistance function for providing or controlling recuperation, such as a coasting recuperation assistant (SRA). Such an SRA can, for example, control or vary the recuperation level and thereby also influence the longitudinal stability or speed of the vehicle, but itself does not generate any driving FAS torque, at least outside of near-standstill speed ranges.

[0038] Correspondingly different types of driver assistance functions, such as ACC and SRA, can be implemented separately, for example, as separate driver assistance systems. Likewise, these driver assistance functions can be implemented or provided by the same driver assistance system. In this case, the various driver assistance functions can, for example, use at least some of the same components or the same chain of operations. This can potentially lead to greater efficiency, for example, in terms of component utilization and / or energy consumption, as well as cost savings.

[0039] A near-standstill range or speed range, in the present sense, can be, for example, a creep speed range of the respective motor vehicle, in which the motor vehicle can or would move without driver intervention, i.e., without manual operation of, for example, a brake and / or acceleration control element, and without automated longitudinal control requests or without automated longitudinal control intervention by a drive assistance function due to an active creep function or a creep torque specified – for example, as a foot-point torque. The near-standstill range can, for example, be a speed range from 0 km / h to approximately 7 km / h.

[0040] In a further process step, it is checked whether the torque determined in this way is smaller than the frozen FAS torque. If this is the case, the frozen FAS torque is then reduced to the determined torque, i.e., its value. In other words, the FAS torque can then be capped or limited to the determined torque.

[0041] The present invention can prevent under-braking during a manual braking intervention during an automated acceleration phase or24-1744

[0042] 9

[0043] The FAS torque is limited. Furthermore, by initially freezing the FAS torque applied at the start of manual brake control operation, a high degree of flexibility is achieved for further handling of the frozen FAS torque and thus for shaping the vehicle's behavior. For example, reducing the frozen FAS torque can be parameterized to prevent uncomfortable, difficult-to-control, unintuitive, and / or inconsistent vehicle behavior.

[0044] In particular, this allows for a manual longitudinal control intervention by the driver to have an immediate effect corresponding to the type of intervention, i.e., the driver's intention. In this case, reducing or limiting the FAS torque, or a corresponding calculation or control logic, can be integrated into the logic or control system for at least assisted or at least partially automated longitudinal control. This control logic, or a corresponding operating or control mode, which freezes and, if necessary, reduces the FAS torque—that is, the resulting torque for regulating a target acceleration requested by the driver assistance system—to the torque a manual driver would experience in the same driving situation without pedal input, can therefore be integrated, implemented, or set within the longitudinal control system itself.This allows for the efficient implementation of the described functions and the effective and efficient avoidance of the described problems in corresponding potentially problematic situations with a positive FAS moment.

[0045] In one possible embodiment of the present invention, the determined torque, which would alternatively be applied under the described conditions in the corresponding driving situation, is or includes a recuperation torque. Here, for example, the foot-point torque or total foot-point torque that would result in the corresponding driving situation under the stated conditions can be determined. It can therefore be determined, for example, whether the vehicle would creep at the given operating point and / or what recuperation torque would be applied or set, or the like. Thus, it can be determined, for example, how the vehicle would behave in the respective driving situation in a coasting mode with inactive or deactivated ACC and / or other drive assistance functions, i.e., without longitudinal control intervention, and without longitudinal control intervention by the driver. The recuperation torque is 24-1744

[0046] 10

[0047] A negative torque, therefore, has a decelerating effect. In particular, the torque that would be set accordingly can be determined as a recuperation torque or an overall negative torque due to a recuperation function or recuperation torque. Thus, the FAS torque can be limited or reduced to a negative torque or a negative, i.e., decelerating, value. This ensures that the driver-initiated deceleration or braking torque indicated by the driver via the brake control is not counteracted by automatic acceleration or a positive FAS torque. This allows the driver's desired action to be implemented particularly effectively. Furthermore, this can improve traffic safety and prevent misleading other road users.

[0048] In a further possible embodiment of the present invention, the FAS torque is frozen only in an additive operating mode as described and, if necessary, reduced to the determined torque. In such an additive operating mode, the FAS torque generated by the driver assistance system (i.e., the torque provided to implement the target acceleration requested by the driver assistance system) and the driver-requested torque resulting from the positions of the manually operated brake control and / or the manually operated acceleration control are combined purely additively to form an actual or total torque. In the additive operating mode, the FAS torque and the driver-requested torque can thus be added together. The resulting sum can then be set as the total torque or combined with other contributing torques to form the total torque to be set.In additive operating mode, for example, when the driver assistance system and the driver are simultaneously active for longitudinal control of the vehicle, there is no blending between the corresponding requirements of the driver assistance system and the driver, or between corresponding torques, and, for example, no partial consideration of the driver assistance system's target acceleration and / or the driver's desired torque or a corresponding – positive or negative – driver-desired acceleration. The described calculation or control logic for limiting or reducing the driver assistance system's torque when braking is detected, i.e., when manual actuation of the brake control is detected during longitudinal control by the driver assistance system, can be automatically applied in additive operating mode.

[0049] 11

[0050] The calculation or control logic can be used, i.e., activated or executed. For example, the corresponding calculation or control logic can be automatically used or integrated by a vehicle system configured to execute the method according to the invention, or by the driver assistance system, or the brake and / or drive system, or a corresponding brake and / or drive control unit. In another, non-additive operating mode, the calculation or control logic can, for example, be deactivated, or its execution or evaluation can be omitted.

[0051] The additive operating mode can be requested or set by the driver assistance system, or detected or set based on a corresponding signal from the driver assistance system. Similarly, the additive operating mode can be set or activated manually by the driver, or the like. The additive operating mode can offer certain advantages over other operating modes, at least in specific situations. For example, in the additive operating mode, the driver can avoid having to bridge or travel a period of free play when applying the brake control before the application has an effect on the vehicle's longitudinal stability.In other operating modes, a conflict or competition between the driver's control influences and the control influences of the driver assistance system can be avoided in other ways, so that, for example, freezing and possibly reducing the FAS torque when the driver operates the brake control is not necessary. Thus, by applying the present invention only in the additive operating mode, individually optimized vehicle control can be implemented for different situations or requirements.

[0052] In another possible embodiment of the present invention, the frozen FAS torque is reduced only gradually to the determined torque. In other words, the adjustment of the frozen FAS torque to the determined torque does not occur instantaneously or abruptly, but over a certain period of time. In particular, the frozen FAS torque can be reduced continuously to the determined torque. In a possible further development of the present invention, the reduction of the frozen FAS torque can, in particular, be carried out with at most a predetermined maximum gradient, i.e., with at most a 24-1744

[0053] 12

[0054] The reduction of the frozen FAS torque can be carried out according to a predefined maximum rate or rate of reduction. The frozen FAS torque can be reduced in a predefined manner, for example, linearly, according to a predefined function, or along a predefined curve. The rate or rate of reduction for the frozen FAS torque can, for example, be fixed or determined depending on the magnitude of the initially frozen FAS torque, the difference between the initially frozen FAS torque and the measured torque, and / or the vehicle speed. For example, a higher rate or rate of reduction can be used for a larger initially frozen FAS torque and / or a larger difference between the measured and frozen torques.Similarly, the degradation rate or rate can be determined, for example, such that the reduction of the frozen FAS moment to the determined moment is completed within a specified time period – at least as long as the specified maximum gradient does not have to be exceeded. Otherwise, the time period can be extended accordingly and the maximum gradient used.

[0055] Because the reduction of the frozen FAS torque occurs gradually or with a limited gradient, any resulting changes in the vehicle's behavior can be comfortably and safely compensated for or controlled by the driver as needed, for example, by gradually increasing or decreasing the force applied to the brake and / or accelerator controls depending on the situation. This would not be readily possible if, for example, the FAS torque were completely and abruptly reduced to zero upon initial activation of the brake controls. Therefore, the proposed embodiment and further development of the present invention enables particularly comfortable and safe vehicle operation.

[0056] In another possible embodiment of the present invention, the reduction of the frozen FAS torque to the determined torque is started without waiting time. In other words, the frozen FAS torque can be reduced as soon as possible, i.e., as soon as all the necessary data are available, i.e., as soon as the actuation of the brake control element has been detected and the value of the determined torque is available. In the present case, the reduction of the 24-1744

[0057] 13

[0058] The frozen FAS moment, for example, is not only triggered after manual application of the brake control for a certain predetermined minimum period, or after a predetermined force has been reached, or similar. By avoiding such a waiting time or delay, a particularly safe, intuitive, and consistent vehicle behavior can be achieved, which can benefit driving comfort and safety.

[0059] In a further possible embodiment of the present invention, the reduction of the frozen FAS torque to the determined torque is carried out independently of the force applied to the brake control. This prevents, for example, the vehicle from accelerating unnecessarily for an extended period, particularly when the initial frozen positive FAS torque is relatively high and the brake control is applied with comparatively little or no force. Furthermore, the reduction of the FAS torque can then be initiated very early, i.e., without delay, upon detection of the brake control activation. This allows the driver's request to decelerate the vehicle to be implemented particularly quickly and directly, resulting in especially intuitive and safe vehicle behavior.

[0060] In a further possible embodiment of the present invention, the freezing of the FAS torque, in particular the FAS torque reduced or limited to the determined torque, is automatically terminated when or as soon as there is no longer any manual actuation of the brake control element or when such actuation is no longer detected. With or immediately after the freezing of the FAS torque is terminated, the driver assistance system can then freely and fully intervene in the longitudinal control of the vehicle again. Likewise, during an adaptation or transition phase, with or after the freezing of the FAS torque is terminated, the set FAS torque can be gradually changed to a currently applicable value, i.e., a current target value of the FAS torque, before the free or complete control of the longitudinal control of the vehicle by the driver assistance system is enabled or released.This prevents sudden, abrupt or jerky changes in the vehicle's behavior and thus achieves particularly comfortable and safe vehicle behavior.24-1744.

[0061] 14

[0062] The corresponding gradual adjustment or modification of the FAS torque during the transition or adaptation phase can be carried out precisely or at most with the predetermined maximum gradient specified elsewhere, or precisely or at most with another predetermined second maximum gradient. The proposed embodiment of the present invention can enable an uninterrupted or smooth, and therefore particularly comfortable and safe, transition between an operating phase with manual longitudinal guidance intervention by the driver and a subsequent phase of at least assisted or at least partially automated operation of the vehicle. In particular, the driver then does not need to manually release or activate the longitudinal guidance or longitudinal control by the driver assistance system.

[0063] The present invention also relates to a vehicle system for a motor vehicle. The vehicle system according to the invention has an input interface for acquiring input data. This input data can, for example, specify or include the quantities or parameter values ​​mentioned in connection with the method according to the invention for determining or characterizing the respective driving situation and / or for determining the torque that would be applied in the respective driving situation in manual operation without longitudinal control interventions by the driver. Likewise, the input data can, for example, specify or include the target acceleration requested by the driver assistance system (FAS) – positive or negative – and / or a corresponding FAS torque for implementing the target acceleration.Similarly, the input data can, for example, indicate or signal whether and, if so, to what extent the driver intervenes in the longitudinal control, i.e., by operating or activating a corresponding brake and / or acceleration control element of the vehicle. Likewise, the input data can, for example, specify or include a derived or determined driver-requested acceleration and / or a corresponding driver-requested torque – positive or negative. The input data can also specify or include other or additional quantities or data.

[0064] The vehicle system also includes a data processing unit for processing the input data, for example, to generate respective results and / or corresponding control signals. Furthermore, the vehicle system includes an output interface for outputting corresponding results and / or 24-1744

[0065] 15

[0066] Control signals, for example, to the driver assistance system or another part, module, or function of the driver assistance system and / or to the braking and / or drive system, or the like. The input interface and the output interface can be separate interfaces or combined or integrated in a common, bidirectional interface. The input interface and the output interface can each be implemented wholly or partially in hardware and / or in software. According to the invention, the vehicle system is configured to automatically execute the method according to the invention.

[0067] The vehicle system, in particular its data processing unit, can, for example, comprise a processing unit, such as a microprocessor, microchip, microcontroller, or the like, and a computer-readable data storage device coupled thereto. This data storage device can then, for example, contain a corresponding operating or computer program that encodes or implements the process steps, measures, or sequences described in connection with the method according to the invention, or corresponding control instructions. This operating or computer program can then be executed by means of the processing unit to carry out the corresponding method or to effect its execution. The vehicle system according to the invention can, in particular, be the vehicle system mentioned in connection with the method according to the invention.The vehicle system according to the invention can be a separate system, for example, its own control unit, or it can comprise other components. Likewise, the vehicle system according to the invention can be combined or integrated, for example, with the driver assistance system and / or with a control system or control unit for brake or drive control.

[0068] The present invention also relates to a motor vehicle that is equipped for both manual longitudinal control, i.e., control by a driver, and for at least assisted or at least partially automated longitudinal control by a driver assistance system. The motor vehicle according to the invention can therefore, in particular, have a corresponding driver assistance system. The motor vehicle according to the invention is equipped with the vehicle system according to the invention and can accordingly, in particular, be configured for the automatic execution or application of the method according to the invention. The motor vehicle according to the invention can therefore, in particular, be the motor vehicle mentioned in connection with the vehicle system according to the invention and / or in connection with the method according to the invention.

[0069] Further features of the invention may become apparent 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 shown below in the description of the figures and / or in the figures themselves, can be used not only in the combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0070] The drawing shows in:

[0071] Fig. 1 shows a partial schematic representation of a motor vehicle designed for manual and automated operation and for avoiding underbraking during simultaneous manual and automated longitudinal control interventions; and

[0072] Fig. 2 shows an exemplary schematic flow chart for a corresponding operating or control procedure.

[0073] Fig. 1 shows a partial schematic representation of a motor vehicle 1, which can be controlled and longitudinally guided by a driver 2 in a manual operating mode and by a driver assistance system 3 in an automated operating mode. For manual driving, the motor vehicle 1 is shown here as an example with an accelerator pedal 4 and a brake pedal 5, which can be operated by the driver 2. When the accelerator pedal 4 and / or the brake pedal 5 is actuated, a corresponding signal can be sent to a brake and drive system 6 of the motor vehicle 1 to implement the corresponding driver command. Likewise, the driver assistance system 3 can send signals to the brake and drive system 6 for automated longitudinal guidance. The brake and drive system 6 can then control corresponding actuators to apply the appropriate torques.to realize corresponding positive or negative accelerations in the respective direction. In an additive operating mode, it can be provided that if the driver 2 manually intervenes in longitudinal control, for example, by pressing the brake pedal 5, a driver assistance system (FAS) torque that is currently set to implement a target acceleration requested by the FAS 3 is frozen, for example, to avoid a control conflict or controller competition between the driver 2 and the driver assistance system 3. If the driver assistance system 3 intends acceleration, a correspondingly positive FAS torque can be frozen. For example, a relatively large positive FAS torque can be frozen when driving uphill. When the driver 2 presses the brake pedal 5, a brake light of the vehicle 1 may then illuminate if the vehicle 1 continues to accelerate.In previous approaches, a sudden, abrupt removal or zeroing of the positive frozen FAS moment, or a degradation to a fallback level based on a detected under-braking, could potentially occur somewhat later. However, this would not be optimal or desirable and is avoidable in this case.

[0074] The motor vehicle 1 also features a vehicle system 7, which is shown separately for illustrative purposes only. The vehicle system 7 is connected, at least indirectly, via an interface 8 to the accelerator pedal 4 and the brake pedal 5, or corresponding sensors or signal transmitters, to the driver assistance system 3, and to the brake and drive system 6. The vehicle system 7 can acquire various data or signals via the interface 8. These can, for example, indicate or determine the accelerator pedal 4 and the brake pedal 5 operated by the driver 2, as well as positive or negative accelerations or corresponding torques requested by the driver assistance system 3. Likewise, the vehicle system 7 can acquire further data or signals, also via the interface 8, which may indicate or characterize the current driving situation.

[0075] To illustrate the functionality of the vehicle system 7, Fig. 2 shows an exemplary schematic flowchart 11 for a corresponding operating or control procedure. The procedure can be started in a process step S1. Here, for example, the vehicle system 7 can be activated or put into operation. Likewise, the additive operating mode can be activated here, for example. In a process step S2, the vehicle system 7 can, for example, initiate continuous monitoring of the driving situation, at least to the extent that it is not already active, as well as responding to target accelerations and / or corresponding FAS torques requested by the driver assistance system 3 and to manual actuations of the accelerator pedal 4 and the brake pedal 5.

[0076] In a process step S3, for example the vehicle system 7 can continuously check whether the brake pedal 5 is actuated at the same time as a requested, in particular positive, FAS target acceleration, i.e. whether longitudinal guidance requirements of the driving assistance system 3 and the driver 2 are present or active at the same time.

[0077] If this is not the case, a current longitudinal guidance request from the driver assistance system 3 or a current longitudinal guidance request from the driver 2 can be implemented by the brake and drive system 6 in a process step S4.

[0078] If, in process step S3, manual actuation of the brake pedal 5 is detected while simultaneously the driver assistance system 3 requests a non-zero target acceleration for the driver assistance system (FAS) or a corresponding positive FAS torque is provided by the brake and drive system 6, the process can continue with process steps S5a and S5b. In process step S5a, the current FAS torque, i.e., the torque provided when the actuation of the brake pedal 5 was initially detected, can be frozen, for example, by the vehicle system 7. For example, an alternative torque can be determined in parallel in process step S5b.The alternative moment is a moment that would be applied in the current driving situation, or a corresponding driving situation, or a driving situation similar to the current driving situation, for example according to a predetermined deviation or similarity criterion, or at least up to a predetermined maximum deviation, if the driving assistance system 3 did not request a driving or positive FAS target acceleration and the driver 2 did not operate either the accelerator pedal 4 or the brake pedal 5.24-1744.

[0079] 19

[0080] In a process step S6, the frozen FAS torque can then be gradually reduced to the alternative torque thus determined, for example caused or initiated by the vehicle system 7.

[0081] In process step S7, the vehicle system 7 can continuously check whether a predefined end or termination condition for freezing the FAS torque is met. Such an end or termination condition could, for example, be checking whether the driver 2 continues to depress the brake pedal 5 and / or whether the additive operating mode is still active and / or whether the FAS torque actually required or available without restrictions to implement a target acceleration currently requested by the driver assistance system 3 is smaller than the determined alternative torque.

[0082] If, in process step S7, it is detected that the end or termination condition is met, then, for example, caused or initiated by the vehicle system 7, the frozen FAS torque can be gradually adjusted to the value of the alternative torque in a process step S8, resulting in a current or new target value, and the freezing of the FAS torque can be terminated. The current or new target value can be a value or an FAS torque that is required or would be necessary to implement the target acceleration currently requested by the driver assistance system 3.

[0083] In the procedure described here, a first calculation or control logic can be applied or executed to freeze the FAS torque before a second calculation or control logic is applied or executed to cap or limit, and if necessary, reduce, the frozen FAS torque. In additive operating mode and upon detection of manual braking, the second calculation or control logic can be automatically activated, and only then.

[0084] Overall, the examples described show how a reduction of frozen positive moments to a driver's foot point, or a foot point moment or foot point level, can be realized and applied in additive operation in the event of braking.24-1744

[0085] 20

[0086] Reference symbol list

[0087] 1 motor vehicle

[0088] 2 drivers

[0089] 3 Driver assistance systems

[0090] 4 Accelerator pedal

[0091] 5 Brake pedal

[0092] 6. Braking and drive system

[0093] 7 Vehicle system

[0094] 8 Interface

[0095] 9 processor

[0096] 10 Data storage

[0097] 11. Schedule

[0098] S1 - S8 process steps

Claims

24-1744 21 Patent claims 1. Method (11) for controlling a motor vehicle (1) which is equipped for manual longitudinal control by a driver (2) and for at least assisted longitudinal control by a driver assistance system (3), wherein during the operation of the motor vehicle (1) automatically - continuous monitoring of the current driving situation as well as target accelerations requested by the driver assistance system (3) and manual actuations of a brake control element (5) of the motor vehicle (1) is carried out, - if, at the same time as a positive FAS target acceleration is requested by the driver assistance system (3), a manual actuation of the brake control element (5) is detected, an FAS torque that was initially actuated to implement the requested positive FAS target acceleration upon initial detection of this actuation of the brake control element (5) is frozen, - it is determined which torque would be actuated in the current driving situation without any driving longitudinal control intervention by the driver assistance system (3) and without any manual longitudinal control intervention by the driver (2), - if the determined torque is smaller than the frozen FAS torque, the frozen FAS torque is reduced to the determined torque.

2. Method (11) according to claim 1, characterized by the fact that The determined moment includes a recuperation moment.

3. Method (11) according to any one of the preceding claims, characterized by the fact that the FAS torque only in an additive operating mode, in which the FAS torque caused by the driver assistance system (3) and a driver request torque resulting from the position of the manually operated brake control element (5) and / or a manually operated acceleration control element (4) are additively combined to form an actually set torque.24-1744 22 The total moment is combined, frozen, and, if necessary, reduced to the determined moment.

4. Method (11) according to any one of the preceding claims, characterized by the fact that The frozen FAS moment is only gradually reduced to the determined moment.

5. Method (11) according to claim 4, characterized by the fact that The reduction of the frozen FAS moment to the determined moment is carried out with a maximum predetermined gradient.

6. Method (11) according to any one of the preceding claims, characterized by the fact that The reduction of the frozen FAS moment to the determined moment is started without waiting time.

7. Method (11) according to any one of the preceding claims, characterized by the fact that the reduction of the frozen FAS torque to the determined torque takes place independently of the strength of the manual actuation of the brake control element (5).

8. Method (11) according to any one of the preceding claims, characterized by the fact that The FAS momentary freezing is automatically terminated when no further action is detected on the brake control element (5).

9. Vehicle system (7) for a motor vehicle (1), comprising an input interface (8) for acquiring input data, a data processing device (9, 10) for processing the input data, and an output interface (8) for outputting resulting results and / or control signals, wherein the vehicle system (7) is configured to automatically execute the method (11) according to any one of the preceding claims.

10. Motor vehicle (1) configured for manual longitudinal control by a driver (2) and for at least assisted longitudinal control by a driver assistance system (3), comprising a vehicle system (7) according to claim 9.

Images