Method and assistance device for cooperation between automated and manual vehicle guidance, and corresponding motor vehicle

Abstract

The invention relates to a method and an assistance device for controlling a drive system (2) of a motor vehicle (1), and to a correspondingly configured motor vehicle (1). In the method, when a brake pedal (7) of the motor vehicle (1) is actuated, a difference is determined between a driver-desired braking torque (14), which is composed of a brake pedal torque corresponding to the position of the brake pedal (7) and a predefined offset torque (15), and a decelerating torque (16) requested by a driver assistance system (8) of the motor vehicle (1). If the latter has a weaker decelerating effect, a total decelerating torque (18) to be set in each case is determined according to the difference, and with increasing actuation of the brake pedal (7), by changing over, in a manner increasing with the actuation of the brake pedal (7), from the sum (17) of the requested decelerating torque (16) and the brake pedal torque, which is given when the brake pedal (7) is actuated, to only the driver-desired braking torque (14).

Description

[0001] Method and assistance device for cooperation between automated and manual vehicle control and corresponding motor vehicle

[0002] The present invention lies in the field of automotive engineering and relates to a method and an assistance device for controlling a drive system of a motor vehicle. The invention also relates to a correspondingly configured motor vehicle.

[0003] Motor vehicles today are increasingly equipped with functions and systems for automating vehicle guidance or driving tasks. However, these vehicles are still manually controlled by a driver—at least so far. This can lead to simultaneous control inputs from a driver assistance system for automated vehicle guidance and the driver, which can overlap or even contradict each other. This, in turn, can lead to unexpected or uncomfortable reactions or behaviors from the vehicle.

[0004] Against this background, DE 102021 104692 A1 describes a driver assistance system for a motor vehicle that supports ferry operation at a first level of automation, in which a vehicle occupant intervenes in the vehicle control or can intervene briefly, and a second level of automation, in which the vehicle control can be carried out automatically without such interventions. The driver assistance system is configured to decouple a control element for interventions by the vehicle occupant from the vehicle control when the motor vehicle is operated at the second level of automation. Furthermore, the driver assistance system is configured to generate haptic feedback via the control element when the control element is already decoupled during a transition from the first to the second level of automation, which gives the vehicle occupant the feeling that they can still influence the vehicle control using the control element.

[0005] EP 1 610 992 B1 describes an electronic control system for a vehicle with a hazard computer that has a model for calculating hazard potentials that take into account the activation time of vehicle actuators and longitudinal and lateral dynamic driving situations. Depending on the hazard potentials, it determines graduated control interventions for controlling the vehicle actuators. Depending on the influence of the control interventions on the vehicle's driving dynamics, an evaluation is performed using a determined driver request. Depending on the corresponding evaluation result, the graduated control interventions are then conditionally enabled, enabled, or disabled.

[0006] However, these approaches are not suitable for all cases or do not solve all problems, so there is still a need for improvements in the handling or in the interaction of systems or functions for automated vehicle guidance and manual control interventions.

[0007] Accordingly, it is an object of the present invention to enable a driver of a motor vehicle to comfortably, easily and precisely control the longitudinal direction of the motor vehicle by means of its accelerator pedal.

[0008] This object is achieved by the subject matter of the main claim and the subsidiary claims or the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description and the figures. Features, advantages and possible embodiments that are set out 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 any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims. The method according to the invention can be used to control a drive system of a motor vehicle.Such a drive system can comprise, as controllable devices or actuators, for example, an electric drive motor and / or an internal combustion engine or also a braking system, in particular a friction brake or a friction brake actuator. The method can be carried out automatically in appropriate situations or under appropriate circumstances during operation of the motor vehicle, for example by an assistance device of the motor vehicle configured to carry out the method. In the method, a decelerating torque requested by a driver assistance system configured to at least assist in the longitudinal guidance of the motor vehicle is monitored or continuously recorded. This requested decelerating torque, i.e., the torque inhibiting the movement of the motor vehicle, is also referred to here as the FAS torque (FAS: driver assistance system).Such an ADAS torque can, for example, be requested by the driver assistance system, i.e. output as a setpoint or target value for the drive system, if an obstacle in front of the motor vehicle in the direction of travel or a corresponding risk of collision or, for example, a speed limit below the current speed of the motor vehicle is detected.

[0009] Likewise, in the method according to the invention, the position of a brake pedal of the motor vehicle or its actuation by a driver of the motor vehicle is monitored or continuously recorded. Based on the respective position, i.e. the respective current actuation or the respective current degree of actuation, a corresponding brake pedal torque is determined respectively or continuously, i.e. the resulting brake pedal torque - alone or by means of a predetermined conversion rule. A decelerating torque desired by the driver can therefore be influenced by the driver by correspondingly actuating the brake pedal. Depending on the design of the motor vehicle or the drive system, it can be provided that no decelerating or accelerating torque is actively provided without actuation of the brake pedal, i.e. in its zero or neutral position, and without a currently requested ADAS torque.In particular, a predefined decelerating offset torque can already be active or actively set even without depressing the brake pedal. This offset torque can, for example, be used for recuperation or be brought about by active recuperation, i.e., it can be a recuperation torque. At least while the vehicle is decelerating, the offset torque can therefore always be active or be included in a balance to determine a total torque to be set. The combination or sum of the brake pedal torque - which can be determined directly and completely by the driver depressing the brake pedal - and the offset torque - which cannot be directly influenced by the driver - is referred to here as the driver's desired braking torque. The offset torque can be constant. As the driver presses the brake pedal more forcefully, both the brake pedal torque and, to the same extent, the driver's desired braking torque can increase in magnitude, i.e., become more decelerating.

[0010] In the method according to the invention, when the driver of the motor vehicle actuates the brake pedal, i.e. when the position or angle of the brake pedal changes towards a stronger braking force or deceleration, a difference is determined between the decelerating torque requested by the driver assistance system and the initial driver request braking torque, i.e. the torque given or present at or immediately before the brake pedal actuation. At this point in time, the latter can in particular correspond at least substantially to the predetermined offset torque. Such actuation can here occur or be detected in particular from a previous non-actuation, i.e. a previous state without manual actuation of the brake pedal. In this case, it can therefore be determined by means of a corresponding comparison whether the driver assistance system or the driver is requesting a stronger decelerating torque.

[0011] According to the invention, in the event that the driver's desired braking torque is less decelerating, i.e. greater or more positive or smaller in magnitude than the correspondingly more negative, i.e. more decelerating and thus greater in magnitude, decelerating torque requested by the driver assistance system, a total decelerating torque to be set at a given time - by means of the drive system or its actuators - is determined as a function of the determined difference between the FAS torque and the driver's desired braking torque, for example during or immediately before the actuation of the brake pedal or its detection, with increasing actuation of the brake pedal by the driver.This total torque is determined by a predetermined blending, increasing with the actuation of the brake pedal, from the sum of the FAS torque and the brake pedal torque given when the brake pedal is actuated to only the driver's desired braking torque with a stronger actuation of the brake pedal that depends on the difference. The pure driver's desired braking torque can therefore be used as the total torque at the end of a corresponding blending range. Such blending can, for example, be realized with a correspondingly increasing actuation of the brake pedal as a linear interpolation or linear total torque curve between the torque corresponding to the initially determined sum and a torque dependent on the determined difference or a driver's desired braking torque value determined as a function of the difference.

[0012] The blending of the sum of the ADAS torque and the brake pedal torque with increasing brake pedal application can therefore mean that the total torque is determined by mixing or combining the sum and the driver's desired braking torque. In the corresponding blending range, i.e. a corresponding brake pedal position range or a corresponding torque range, the total torque can therefore lie between the sum of the ADAS torque and the brake pedal torque on the one hand and the driver's desired braking torque on the other. This can therefore be the range of the brake pedal position or brake pedal application or a corresponding brake pedal application force and thus the torque range or

[0013] The total torque range in which the blending takes place is referred to as the blending range. This blending range begins at the point of initial application of the brake pedal, where the total decelerating torque initially corresponds to the sum of the ADAS torque and the brake pedal torque – which is then zero or at least almost zero – according to the brake pedal or its position or application. The blending range ends at the point at which the total decelerating torque corresponds to, and thus reaches, the driver's desired braking torque. This point is therefore only reached if the driver applies the brake pedal sufficiently hard, i.e., presses it sufficiently far.

[0014] In a simple case or in a simple implementation of the invention, the fading can take place continuously and linearly, for example with the brake pedal position or the brake pedal torque, which increases with increasing brake pedal application. For example, a fading or mixing factor can be used that increases or increases linearly with increasing brake pedal application. Such a mixing factor can therefore determine the proportion of the FAS torque and / or the brake pedal torque to the total torque. For example, a mixing factor of 0 can mean that the total torque corresponds to the FAS torque or the sum of the FAS torque and the brake pedal torque, while a mixing factor of 1 can mean, for example, that the total torque corresponds to the driver's desired braking torque.The mixing factor to be used in each case, i.e., the one to be considered when determining the total torque to be applied, can vary in different situations, especially with different ADAS torques. The mixing factor can therefore be redetermined in each situation to achieve the described effect of the total torque at the point or moment determined depending on the initial difference between the ADAS torque and the driver's desired braking torque, or at the corresponding brake pedal position, becoming identical to the driver's desired braking torque. Other implementations or configurations of the blending process are also possible, which will be explained in more detail elsewhere.

[0015] After the total torque to be set has been determined, the electric drive motor can then be controlled to generate this specific total torque.

[0016] The present invention makes it possible to avoid free travel in the brake pedal when the decelerating ADAS torque is active. Such free travel would mean that the total torque and, accordingly, also the deceleration or speed of the motor vehicle does not change despite actuation of the brake pedal, i.e., a changing brake pedal torque. Such free travel would arise, for example, if the driver had to first move the brake pedal to a position in which the thereby displayed brake pedal torque or the driver's desired braking torque corresponds to the current ADAS torque before the brake pedal torque, i.e., the driver's intervention, is taken into account in determining the total torque. However, such behavior can be irritating for many drivers or lead to undesirable panic reactions, as the driver may then have the feeling or impression that the motor vehicle is not responding to their actuation of the brake pedal.This is avoided by the present invention, which can mean greater ease of use and contribute to safety in traffic. At the same time, the blending provided according to the invention, i.e. the gradual greater consideration of the brake pedal torque or the driver's desired braking torque in the overall torque, avoids an abrupt jump in the overall torque when the brake pedal is actuated. The present invention also avoids the disadvantages that would arise if, for example, the sum of the ADAS torque and the brake pedal torque or the driver's desired braking torque were always used as the overall torque. In this case, the motor vehicle could behave in a way that is very unusual and therefore irritating for many drivers. In addition, with the driver assistance system or ADAS torque active, even with a weaker actuation of the brake pedal, i.e. at a smaller pedal angle than in purely manual ferry operation orIn situations without an active decelerating ADAS torque, a limiting range may be reached in which, for example, the vehicle's anti-lock braking system intervenes. Likewise, if the ADAS torque changes during brake pedal application without changing the brake pedal position—a change that cannot be controlled or predicted by the driver—the total torque would change. This would make the vehicle's braking or deceleration behavior unreproducible for the driver, and would make it difficult to reliably and precisely control or modulate it.

[0017] The present invention, however, enables the driver to intervene at any time in a simpler and more controllable manner by operating the brake pedal, or to control the overall torque and thus the behavior or speed of the motor vehicle. Overall, the present invention thus results in improved cooperation between automated and manual driving, or corresponding control interventions or control signals.

[0018] The present invention also relates to an assistance device for a motor vehicle for controlling a drive system of the motor vehicle or corresponding actuators for setting, i.e. generating a respective, in particular decelerating, total torque. The assistance device according to the invention comprises an input interface or a detection or monitoring device for detecting or monitoring a decelerating torque requested by a driver assistance system configured for at least assisted, in particular partially automated, longitudinal guidance of the motor vehicle and the position or actuation of the brake pedal of the motor vehicle. Furthermore, the assistance device comprises a data processing device for determining, based thereon, a total torque to be set at a particular time, in particular by means of the drive system or its actuators, and an output device orOutput interface for outputting a corresponding control signal to initiate or effect the setting of the respective total torque. Using the respective control signal, the assistance device can, for example, directly control the drive motor and / or a braking system or friction brake, or indirectly effect the setting of the total torque by sending the control signal, for example, to an intermediate drive or engine control unit or the like.

[0019] The assistance device according to the invention is configured to carry out, in particular automatically, the method according to the invention. For this purpose, the assistance device, in particular its data processing device, can comprise, for example, a processing device, such as a microchip, microprocessor, microcontroller, or the like, and a computer-readable data memory coupled thereto. An operating or computer program can then be stored in this data memory, which codes or implements the method steps, measures, or sequences mentioned in connection with the method according to the invention, or corresponding control instructions. This operating or computer program can then be executable by means of the processing device in order to carry out the corresponding method or to effect its execution.The assistance device according to the invention can, in particular, be the assistance device mentioned in connection with the method according to the invention or correspond to it. For example, the assistance device according to the invention can be configured as a vehicle control unit.

[0020] According to the present invention, the total torque can be set, i.e., caused or generated, exclusively by the electric drive motor—at least up to a predetermined maximum total torque or a maximum decelerating total torque that can be set or generated by the electric drive motor—in particular without the actuation or contribution of a friction brake, for example a mechanical or hydraulic one, of the motor vehicle. This enables particularly fast and precise control of the total torque and thus a particularly comfortable, jerk-free behavior or driving feel of the motor vehicle. This is the case because electric machines can typically be controlled or change their state much more quickly than friction brakes, i.e., a conventional braking system. Furthermore, this enables maximized recuperation and thus particularly energy-efficient and low-wear operation of the motor vehicle.Likewise, the total deceleration torque to be applied can be generated entirely or partially by means of a friction brake. This allows the present invention to be used flexibly in differently equipped motor vehicles.

[0021] In one possible embodiment of the present invention, the assistance device is configured to perform the cross-fading such that, in the cross-fading range, the decelerating total torque increases, at least on average, less sharply with increasing actuation of the brake pedal than the brake pedal torque or the driver's desired braking torque. This can apply in particular at any point in the cross-fading range. The total torque can therefore become negative more slowly in the cross-fading range than with the same course of brake pedal actuation by the driver in purely manual driving mode, i.e. without an active driver assistance system or without a requested or applied ADAS torque. However, since the total torque nevertheless becomes more negative in the cross-fading range with increasing actuation of the brake pedal, there is no free travel in the brake pedal and the driver can notice that the motor vehicle reacts immediately to his actuation of the brake pedal.The curve of the total torque in the fade-in range proposed here can prevent a sudden, jumpy increase in deceleration when the brake pedal is depressed. For example, the total torque in the fade-in range can be linear. This allows the driver to control the deceleration of the vehicle in the fade-in range particularly easily and precisely. Likewise, the total torque can, for example, become more negative more slowly at the beginning or in a first section or area of ​​the fade-in range than in an end area, i.e. a last area or section of the fade-in range. The beginning area of ​​the fade-in range is the area following the initial application of the brake pedal, i.e. in which the total torque is greater, i.e. more positive, than in the end area of ​​the fade-in range. In the end area of ​​the fade-in range, the curve or gradient of the total torque can follow the curve or gradient.the gradient of the driver's desired braking torque. In a corresponding embodiment of the present invention, the assistance device can therefore be configured to carry out or adjust the crossfading non-linearly with increasing actuation of the brake pedal, i.e. with a correspondingly stronger or more negative brake pedal torque or driver's desired braking torque. By means of such a course of the total torque, the changes or rates of change of the total torque can be kept particularly small both at the beginning of the crossfade range or upon entry into the crossfade range and towards the end of the crossfade range or upon exiting the crossfade range towards the pure use of the driver's desired braking torque. In this way, corresponding kinks in the course of the total torque can be weakened or avoided.This allows the driver to control the overall torque particularly easily and precisely, resulting in a particularly smooth and jerk-free driving experience.

[0022] In a further possible embodiment of the present invention, the assistance system is configured to determine or use the corresponding driver-desired braking torque as the total decelerating torque to be set when the brake pedal is actuated or positioned beyond the point at which the total decelerating torque corresponds to the driver-desired braking torque, i.e., the blending is complete, for example, the point at which the brake pedal is actuated or positioned even more strongly or further. In other words, after the driver-desired braking torque is reached at the end point of the blending range, only the driver-desired braking torque is followed. Thus, the ADAS torque can then be disregarded—at least as long as its magnitude is smaller than the driver-desired braking torque. In this case, the driver is the sole torque controller.In general, it can be assumed that stopping the motor vehicle more quickly is safer than stopping more slowly, and that drivers only apply the brake pedal with sufficient force in situations where this is actually or at least potentially appropriate or necessary. At the same time, it is known that today's driver assistance systems do not always operate completely error-free and correctly, or are unable to recognize or interpret the respective environment or situation. Therefore, the embodiment of the present invention proposed here can lead to or contribute to a particularly high level of safety in traffic.

[0023] In a further possible embodiment of the present invention, the assistance device is configured to determine the end point of the blending, at which the total decelerating torque reaches the driver's desired braking torque, i.e., corresponds to it, upon initial actuation of the brake pedal by the driver of the motor vehicle, depending on the then, i.e., initially given difference between the driver's desired braking torque and the decelerating torque requested by the driver assistance system. In other words, the length or extent of the blending range, i.e., the torque or brake pedal position at which the blending to the pure driver's desired braking torque is or should be completed, and thus the corresponding end of the blending range toward stronger brake pedal actuation, is determined situation-dependently or dynamically.From this, the curve or gradient of the total torque to be achieved or set in the crossfade area can be determined. The crossfade can then be performed accordingly, at least as long as the crossfade area is not left.

[0024] If, for example, the driver fully releases the brake pedal within the fade-through range, the current fade-through range is exited. If the brake pedal is subsequently depressed again, a new fade-through range can then be entered, for which the fade-through, i.e., the curve of the total torque, can be redetermined individually or depending on the situation. However, if the driver releases the brake pedal after exiting the fade-through range and applying more force to the brake pedal, the total torque can, for example, follow the curve present or passed through in the last fade-through range in the reverse direction, provided the ADAS torque remains at least substantially unchanged.

[0025] The proposed dependence of the blending, i.e., the progression of the total torque with increasing brake pedal application, on the difference, i.e., the difference between the ADAS torque and the driver's desired braking torque, can achieve a correspondingly situation-adapted behavior of the vehicle. This can prevent larger jumps in the progression of the total torque or excessive gradients of the total torque when the brake pedal position changes. This allows the total torque, i.e., ultimately the deceleration or speed of the vehicle, to be controlled particularly easily and precisely by the driver in different situations.

[0026] In a possible development of the present invention, the assistance device is configured to determine the end point of the cross-fade or cross-fade range as or proportional to the sum of the driver's desired braking torque and the difference between the requested decelerating torque and the driver's desired braking torque multiplied by a predetermined factor. In particular, the corresponding factor can be greater than 1. For example, with an initial brake pedal torque of 0 Nm and a predetermined offset torque of -500 Nm, i.e. a driver's desired braking torque of -500 Nm and an initially given FAS torque of -1000 Nm and a predetermined factor of 2, it can be determined that the end point of the cross-fade range should be -500 Nm + 2 ■ (-1000 Nm - (-500 Nm)) = -1500 Nm.With a factor of 2, the blending should be completed when the driver, by applying a sufficiently strong brake pedal pressure, applies twice the initial difference between the ADAS torque or the sum of the ADAS torque and the brake pedal torque on the one hand, and the driver's desired braking torque or the offset torque on the other hand, as the brake pedal torque. According to the development of the invention proposed here, the end point of the blending can be determined particularly easily and with little effort, while also being situation-dependent. This enables a simple and practical implementation of the present invention.

[0027] In a further possible embodiment of the present invention, the end point of the cross-fading depends on existing or active customer or vehicle or assistance functions of the respective motor vehicle. The end point can therefore be determined in each case as a function of the existing or active customer or vehicle or assistance functions of the motor vehicle. For example, the factor mentioned elsewhere, by which the difference between the combination of the ADAS torque with the brake pedal torque and the driver's desired braking torque is multiplied, can be fixed depending on the corresponding equipment of the motor vehicle. Likewise, the assistance device can, for example, be configured to dynamically adapt or set this factor in each case as a function of the respectively active assistance functions.The embodiment of the present invention proposed here allows it to be used in a situation-dependent or vehicle-dependent manner in different situations or motor vehicles. For example, with active assistance functions for stabilizing the motor vehicle or for wheel slip control or for preventing the wheels of the motor vehicle from locking, a faster cross-fade, i.e. an at least on average greater gradient of the total torque in the cross-fade range, could be provided or permitted than without the activity or presence of such assistance functions. Likewise, for example, a slower cross-fade, i.e. a longer orThe more assistance functions for environmental detection are active and / or the higher-quality, more effective, or more reliable these assistance functions are, the larger the blending range and thus, at least on average, a smaller gradient of the total torque in the blending range can be provided, determined, or maximum permitted. More or higher-quality assistance functions for environmental detection can reduce the probability that an acute collision risk remains undetected, so that decelerating or stopping the vehicle as quickly as possible may then be less important than, for example, better or more precise control of the total torque by the driver.

[0028] In a further possible embodiment of the present invention, a maximum extent of the fade range, in which the fade from the sum of the FAS torque and the brake pedal torque to the pure driver-desired braking torque occurs, is limited to a predetermined maximum value. In a situation-dependent or dynamic determination of the end point of the fade range, which determines the length or extent of the fade range, there may, for example, be various predetermined variables or influencing factors or parameters that influence the determination of the end point, i.e., the respective length or extent of the fade range, and each individually lead to an enlargement or lengthening of the fade range, i.e., a shift of the end point of the fade range toward larger magnitude torques or a stronger brake pedal actuation or a larger brake pedal angle.The specified maximum value can then be specified in such a way that it is already reached before all of these variables, influencing factors, or parameters have been taken into account - at least as long as they have their maximum values. In other words, a maximum length or extent of the blending range resulting from a specified determination or calculation can be greater than the specified maximum value. This ensures that when the brake pedal is applied, the driver becomes torque-controlling after an adjustment range, i.e. pedal travel, corresponding to the specified maximum value, at the latest, and thus has full and precise control over the overall torque. In other words, it can be ensured that the driver finds the usual and expected vehicle behavior when the brake pedal is not applied too forcefully.This can provide good operating and user comfort and contribute to improved safety by avoiding overly unusual vehicle behavior.

[0029] The present invention also relates to a motor vehicle comprising a controllable drive system or controllable actuators for setting a total torque, in particular a decelerating torque, a driver assistance system for at least assisted, in particular partially automated or conditionally automated, longitudinal guidance of the motor vehicle, and the assistance device according to the invention. The motor vehicle according to the invention is thus configured to carry out the method according to the invention. The motor vehicle according to the invention can, in particular, be the motor vehicle mentioned in connection with the method according to the invention and / or in connection with the assistance device according to the invention, or correspond thereto.

[0030] Further features of the invention may emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0031] The drawing shows:

[0032] Fig. 1 is a schematic representation of a motor vehicle that can be controlled manually and by means of a driver assistance system and is configured for comfortable, corresponding cooperative control;

[0033] Fig. 2 shows an exemplary diagram with temporal progressions of various variables to illustrate cooperative control in a first situation; and Fig. 3 shows an exemplary diagram with temporal progressions of various variables to illustrate cooperative control in a second situation.

[0034] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0035] Fig. 1 shows a schematic representation of a motor vehicle 1 with a drive system 2. This drive system 2 here comprises, for example, an electric machine 3. The motor vehicle 1 also has a traction battery 4 and a braking system 5, which can also be part of the drive system 2 or coupled to it. The motor vehicle 1 can be controlled by a driver 6. To do so, the driver 6 can, for example, actuate a brake pedal 7, indicated schematically here. Likewise, the motor vehicle 1 can have an accelerator pedal that can be actuated by the driver 6 for acceleration, which is not explicitly shown here for the sake of clarity. Likewise, the motor vehicle 1 can be controlled or guided by a driver assistance system 8 in an assisted or at least partially automated operating mode.

[0036] It may then happen that the manner in which the motor vehicle 1 is guided by the driver assistance system 8 does not correspond to the wishes of the driver 6. If the driver 6 then intervenes in the control or guidance of the motor vehicle 1 by actuating the brake pedal 7, this may result in contradictory or competing control signals or requirements for the drive system 2. To handle such situations, the motor vehicle 1 also has a correspondingly configured assistance device 9. This can, for example, be coupled to the other aforementioned devices or components, for example via an on-board electrical system of the motor vehicle 1. Schematically, the assistance device 9 is coupled here via an interface 10, in particular a bidirectional one, to the driver assistance system 8, the drive system 2 and the brake pedal 7 or a sensor or indicator for an actuation or position of the brake pedal 7.Via the interface 10, the assistance device 9 can, for example, acquire corresponding data or signals and output corresponding control signals. To process the acquired data or signals, the assistance device 9 comprises a data processing device, which is schematically represented here by a processor 11 and a computer-readable data storage device 12 coupled thereto.

[0037] To illustrate the function or mode of operation of the assistance device 9, Fig. 2 shows a first diagram 13 for an exemplary first driving situation. In this first diagram 13, curves of various variables or parameters are plotted over time t, assuming a linearly increasing actuation of the brake pedal 7 by the driver 6. Specifically, a curve of a driver-desired braking torque 14 is shown here, for example. This driver-desired braking torque 14 can, for example, initially be negative even without actuation of the brake pedal 7, which can lead to a deceleration of the motor vehicle 1, for example due to recuperation, i.e., regenerative operation of the electric machine 3, even without actuation of the brake pedal 7 or intervention of the driver assistance system 8.Without actuation of the brake pedal 7 by the driver 6, the brake pedal 7 is in a zero position or zero setting, in which a negative, i.e. decelerating, driver-desired braking torque 14 may already be present or given due to a corresponding predetermined offset torque.

[0038] Accordingly, the zero position line 15 can then represent a torque of, for example, -500 Nm. The value of the driver's desired braking torque 14, which exists without actuating the brake pedal 7, i.e., in its zero position, is represented here by a corresponding zero position line 15. This zero position line 15 can therefore correspond to the specified offset torque. Likewise, the driver's desired braking torque 14 could be zero without the driver actuating the brake pedal 7, i.e., the zero position line 15 could be at 0 Nm.

[0039] In the present case, the brake pedal 7 may not be actuated until a time t1, and a specific deceleration torque may be requested by the driver assistance system 8. At time t1, the driver 6 actuates the brake pedal 7. The driver 6 depresses the brake pedal 7 with increasing force, which is represented here by the corresponding drop, i.e., the increase in the amount of the driver's desired braking torque 14 from time t1. The driver's desired braking torque 14 shown here is therefore composed of the predetermined, in particular constant, offset torque and a brake pedal torque derived solely from the current position of the brake pedal 7. The latter is not shown separately here for the sake of clarity. Furthermore, the deceleration torque simultaneously requested by the driver assistance system 8 is also entered here as ADAS torque 16.This FAS torque 16 is constant over time and is more negative, i.e., more decelerating, than the initial driver-desired braking torque 14, for example at time t1.

[0040] Furthermore, a curve of a total torque 17 is shown here, which results from the sum of the brake pedal torque and the ADAS torque 16. The driver assistance system 8 or the ADAS torque 16 can take into account or include the value of the driver's desired braking torque 14, i.e., the offset torque, which may also be given without actuation of the brake pedal 7 and is non-zero, so that before time t1, the ADAS torque 16 corresponds to the total torque 17 and a total torque 18, also shown here. The total torque 18 is the torque that is ultimately provided here by the drive system 2, i.e., for example, by the electric machine 3 and / or by the braking system 5, in particular solely by the electric machine 3, or is applied to correspondingly driven wheels of the motor vehicle 1.

[0041] The initial actuation of the brake pedal 7 by the driver 6 is indicated here by a correspondingly abrupt course of a brake pedal activation 19. The jump in the brake pedal activation 19 or in its course at time t1 means that the driver 6 did not actuate the brake pedal 7 before time t1 and at time t1 and during all subsequent times shown here, the brake pedal 7 is deflecting or has deflected at least in some way from its zero position.

[0042] In the situation shown here with an existing decelerating FAS torque 16, i.e. one different from zero, and an initially weaker decelerating driver desired braking torque 14, as well as subsequent actuation of the brake pedal 7 by the driver 6, the assistance device 9 determines the total torque 18 from the time t1 of the initial actuation of the brake pedal 7 by the driver 6 by mixing or combining the driver desired braking torque 14 and the total torque 17. To this end, the assistance device 9 carries out a cross-fading from the initial FAS torque 16 or the total torque 17 at the time t1 to the pure driver desired braking torque 14 at the time t2 in a cross-fading area 20 following the time t1, which extends with increasing brake pedal actuation until a later time t2.The length or extent of the blending range 20, i.e. the moment from which the total torque 18 reaches the driver's desired braking torque 14 with increasing actuation of the brake pedal 7, is determined here by the assistance device 9 using a multiple of the jump height or difference to be bridged in the respective situation between the driver's desired braking torque 14 and the FAS torque 16 or the total torque 17 at time t1, i.e. a corresponding - predetermined or dynamically determined - factor. The manner in which the blending occurs, i.e., the gradual change, from the total torque 17 to the driver's desired braking torque 14 within the blending range 20 thus determined, i.e., the corresponding progression of the total torque 18 in the blending range 20, is then determined or specified by a second factor or a second rule. An exemplary value or progression of this second factor is shown here as a blending factor 21.

[0043] The mixing factor 21 determines at every point in time or at every operating point or operating state, i.e. at every position of the brake pedal 7 and a given ADAS torque 16, the proportion of the driver-desired braking torque 14 or the total torque 17 - and thus also the ADAS torque 16 - that flows into the total torque 18. The mixing factor 21 can, for example, be zero at time t1, so that then exclusively the ADAS torque 16 or the total torque 17 is used as the total torque 18, since then 0% of the driver-desired braking torque 14 flows into the total torque 18. The factor 21 can then increase to a value of 1 by the end of the transition region 20 at time t2, so that then exclusively, i.e. 100%, the driver-desired braking torque 14 is used as the total braking torque 18.As an example, the curve of the mixing factor 21 is shown here for a linear transition from the total torque 17 to the driver-desired braking torque 14 with increasing actuation of the brake pedal 7. However, the mixing factor 21 can also have a different, in particular non-linear, course, which would then result in a correspondingly non-linear curve of the total torque 18 in the transition range 20.

[0044] For example, the specified offset torque can already result in -500 Nm being applied before brake pedal 7 is depressed. If the driver 6 then presses the brake pedal 7 far enough to generate a brake pedal torque of -100 Nm, the driver's desired braking torque is then -600 Nm. If the driver assistance system 8 requests an ADAS torque 16 of -1000 Nm, the fading or mixing factor can then be used to fade from the total torque 17, which is then -1100 Nm, to the driver's desired torque 14. The driver's desired braking torque 14 can, however, also change as the brake pedal 7 is further depressed. The point or the driver's desired braking torque 14 at which the fade-out should be completed is determined by a second factor. This second factor does not correspond to the fading or mixing factor, but describes the difference between the ADAS torque 16 and the desired braking torque 14 relative to the jump height to be overcome.The sum torque 17 and the driver's desired braking torque 14, which is given immediately before the brake pedal is applied, determine when the fade-through should be completed. The jump height or difference to be overcome by the fade-through is 500 Nm. If the second factor is selected as 2, for example, the driver 6 must apply twice this jump height or difference of 500 Nm via the brake pedal 7 to complete the fade-through. In the selected example, this would result in a fading or blending factor of approximately 0.1. This results in a torque of -1050 Nm.

[0045] According to the respective determined total torque 18 to be set, the assistance device 9 can send a corresponding control signal, for example, to the driver assistance system 8 or the drive system 2 or the electric machine 3.

[0046] Fig. 3 shows a second diagram 22 to illustrate a behavior or control of the motor vehicle 1 in a different exemplary situation. Here, similar to Fig. 2, curves of the various variables mentioned are also shown. In the present example, initially, i.e. at least at time t1 and before, the ADAS torque 16 and thus here also the summed torque 17 and the total torque 18 are greater than the driver's desired braking torque 14 without actuation of the brake pedal 7. Here too, from time t1, at which the driver 6 actuates the brake pedal 7 and thus indicates his desire for greater deceleration of the motor vehicle 1, the total torque 18 can be blended or transferred from the ADAS torque 16 or the summed torque 17 to the driver's desired braking torque 14 with increasing actuation of the brake pedal 7.In both illustrated situations, starting from time t2, i.e., when the total torque 18 corresponds to the driver's desired braking torque 14, the driver's desired braking torque 14 can be used as the total torque 18 upon further, i.e., even stronger, actuation of the brake pedal 7 by the driver 6. Accordingly, after time t2, the curve of the total torque 18 follows the curve of the driver's desired braking torque 14.

[0047] Overall, the examples described show how cooperation between automated and manual driving can be realized and handled in a particularly convenient and practical way.

[0048] List of reference symbols

[0049] 1 motor vehicle

[0050] 2 drive system

[0051] 3 electric machine

[0052] 4 Battery

[0053] 5 Braking system

[0054] 6 drivers

[0055] 7 Brake pedal

[0056] 8 Driver assistance system

[0057] 9 Assistance facility

[0058] 10 Interface

[0059] 11 processor

[0060] 12 data storage

[0061] 13 first diagram representation

[0062] 14 Driver-input braking torque

[0063] 15 Zero position line

[0064] 16 FAS Moment

[0065] 17 Total moment

[0066] 18 Total moment

[0067] 19 Brake pedal activation

[0068] 20 Transition area

[0069] 21 Mixing factor

[0070] 22 second diagram representation t time t1, t2 time points

Claims

Patent claims 1. Method for controlling a drive system (2) of a motor vehicle (1), wherein during operation of the motor vehicle (1) - a deceleration moment (16) requested by a driver assistance system (8) which is designed to at least assist the longitudinal guidance of the motor vehicle (1) is monitored, - the position of a brake pedal (7) is monitored and a resulting brake pedal torque is determined, - when the brake pedal (7) is actuated, a difference is determined between the decelerating torque (16) requested by the driver assistance system (8) and a driver-desired braking torque (14), which is composed of the brake pedal torque and a predetermined decelerating offset torque (15), - in the event that the driver's desired braking torque (14) is less decelerating than the requested decelerating torque (16), a total decelerating torque (18) to be set currently by means of actuators (2, 3, 5) of the motor vehicle (1) is determined as a function of the determined difference with increasing actuation of the brake pedal (7) by a blending, increasing with the actuation of the brake pedal (7), in a predetermined manner from the sum (17) of the requested decelerating torque (16) and the brake pedal torque given when the brake pedal (7) is actuated to only the driver's desired braking torque (14).

2. Assistance device (9) for a motor vehicle (1) for controlling a drive system (2) of the motor vehicle (1), comprising a monitoring device (10, 11, 12) for monitoring a decelerating torque (16) requested by a driver assistance system (8) configured for at least assisted longitudinal guidance of the motor vehicle (1) and the position of a brake pedal (7) of the motor vehicle (1), a data processing device (11, 12) for determining, based thereon, a total torque (18) to be set at a given time, and an output device (10) for outputting a corresponding control signal in order to determine the position of the respective total moment (18), wherein the assistance device (9) is arranged to carry out the method according to claim 1.

3. Assistance device (9) according to claim 2, characterized in that the assistance device (9) is designed to carry out the cross-fading in such a way that in a corresponding cross-fading range (20) the decelerating total torque (18) increases, at least on average, less strongly with the increasing actuation of the brake pedal (7) than the driver's desired braking torque (14).

4. Assistance device (9) according to one of the preceding claims, characterized in that the assistance device (9) is designed to carry out the cross-fading non-linearly with increasing actuation of the brake pedal (7).

5. Assistance device (9) according to claim 2 or 4, characterized in that the assistance device (9) is designed to determine the corresponding driver-desired braking torque (14) as the total decelerating torque (18) to be set when the brake pedal (7) is actuated beyond the end point (t2) of the cross-fading, at which the total decelerating torque (18) corresponds to the driver-desired braking torque (14).

6. Assistance device (9) according to one of claims 2 to 5, characterized in that the assistance device (9) is designed to determine the end point (t2) of the cross-fading, at which the total decelerating torque (18) reaches the driver's desired braking torque (14), upon initial actuation of the brake pedal (7) as a function of the then existing difference between the driver's desired braking torque (14) and the decelerating torque (16) requested by the driver assistance system (8).

7. Assistance device (9) according to claim 6, characterized in that the assistance device (9) is designed to determine the end point (t2) of the cross-fading as the sum (17) of the driver's desired braking torque (14) and the difference between the requested decelerating torque (16) and the driver's desired braking torque (14) multiplied by a predetermined factor, which is in particular greater than 1.

8. Assistance device (9) according to claim 6 or 7, characterized in that the end point (t2) of the crossfading is dependent on assistance functions of the respective motor vehicle (1).

9. Assistance device (9) according to one of the preceding claims, characterized in that a maximum extent of a cross-fading area (20) in which the cross-fading takes place is limited to a predetermined maximum value.

10. Motor vehicle (1), comprising actuators (2, 3, 5) for setting a total torque (18), a driver assistance system (8) for at least assisted longitudinal guidance of the motor vehicle (1) and the assistance device (9) according to one of claims 2 to 9.

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