DE102022202286A1 - Method for reducing vehicle instability of a motor vehicle - Google Patents

Abstract

The invention relates to a method for reducing vehicle instability of a motor vehicle (1) and the motor vehicle. The method has the following steps: determining (S2) vehicle stability information (30) which describes the vehicle stability of the motor vehicle (1) by evaluating at least one vehicle stability-related information (22); if the ascertained vehicle stability information (30) is in a predefined value range (S3), providing (S4) an information message (42) for a driver of the motor vehicle (1), which describes at least one measure for reducing the vehicle instability, the at least one measure being at least relates to a control of a longitudinal guide of the motor vehicle (1), in particular a reduction in a driving speed of the motor vehicle (1); Checking (S5) whether the driver has at least partially carried out the at least one measure; and, if the driver has not at least partially carried out the at least one measure, carrying out (S7) an automatic control intervention (43) to reduce the vehicle instability, the control intervention (43) at least relating to the longitudinal guidance of the motor vehicle (1), in particular the reduction of the Driving speed of the motor vehicle (1).

Description

The invention relates to a method for reducing vehicle instability of a motor vehicle. Furthermore, the invention relates to a motor vehicle for carrying out such a method.

On a roadway with bumps, for example at least one pothole and/or at least one rut, vehicle instability of the motor vehicle can occur, for example at a high driving speed of a motor vehicle. The vehicle instability is shown, for example, by the fact that the motor vehicle drives in a rolling motion and/or a driver of the motor vehicle temporarily at least partially loses control of the motor vehicle. This can cause the motor vehicle, for example, to deviate from a road on which it is currently driving and/or to skid. In particular, a motor vehicle with a trailer can be adversely affected in its driving behavior when vehicle instability has occurred.

The DE 10 2012 219 721 A1 shows a driver assistance method for increasing driving comfort in a motor vehicle. As part of the driver assistance method, a state of a route section to be traveled is detected and a lane recommendation for the route section to be traveled is output.

The DE 10 2010 045 162 A1 shows a method and a pothole assistant for lateral guidance of a motor vehicle. A road surface in front of the vehicle in the direction of travel is measured by means of an environment sensor system of the motor vehicle, whereupon potholes occurring in the road surface are determined from the measurement data obtained. An avoidance trajectory can then be determined which avoids wheel contact with the determined pothole.

The DE 10 2014 226 897 A1 shows a method for reducing the risk of swerving in a vehicle with a trailer in the event that the vehicle approaches a danger point. A warning signal is then sent to the vehicle from an external data memory and is further processed in the vehicle. The warning signal can be displayed in the motor vehicle, for example.

It is the object of the invention to provide a solution by means of which vehicle instability that has occurred in a motor vehicle can be recognized and at least reduced.

The object is achieved by the subject matter of the independent patent claim and the subordinate patent claim.

A first aspect of the invention relates to a method for reducing vehicle instability of a motor vehicle. In the context of the invention, vehicle instability is a state of the motor vehicle that leads, for example, to the motor vehicle rolling and/or skidding and/or a trailer rearing up relative to the motor vehicle in the case of a combination of the motor vehicle and the trailer coupled to the motor vehicle. The reason for the vehicle instability can be a vibration of individual components or of the entire motor vehicle, for example due to at least one external factor. The external factor is, for example, a driving surface or floor on which the motor vehicle is driving. An uneven driving surface may be present for the vehicle instability to occur, for example due to at least one pothole, a rut and/or due to the paving of the road, for example cobblestone paving. The vehicle instability can occur when driving on the uneven driving surface, for example when a driving speed of the motor vehicle is greater than a driving speed limit value. The driving speed limit value can depend on the uneven driving surface and can therefore depend, for example, on the type of unevenness and/or a number of unevennesses. The type of unevenness can, for example, at least differentiate between a pothole and a rut. Vehicle instability within the meaning of the invention preferably refers to a deflection of the spring deflection, which occurs despite adhesion to the driving surface and has a perceptibly unfavorable effect on the vehicle stability. If there is no vehicle instability, vehicle stability of the motor vehicle is present.

The method according to the invention has the following steps: Vehicle stability information that describes the vehicle stability of the motor vehicle is determined. The vehicle stability information is determined by evaluating at least one vehicle stability-related information. The vehicle stability information describes, for example, a value between 0 and 1, whereas 0 can stand for vehicle instability and 1 for vehicle stability. The vehicle stability information can have any value between 0 and 1, which means that different levels of vehicle instability or vehicle stability can be differentiated. The vehicle stability-related information is preferably information that can be determined by the motor vehicle itself, for example using a Sensor device of the motor vehicle. The vehicle stability-related information can be, for example, road sign information that describes a road sign, for example in a detection range of a camera of the motor vehicle as a sensor device. The road sign can be a warning sign, for example, which indicates an uneven roadway. As an alternative or in addition to this, the road sign can be an information sign, for example, which indicates, for example, ruts on at least one section of the driving surface, that is to say on at least one section of a road on which the motor vehicle is driving. Such a sign can also be understood as a road sign that indicates an uneven road. Alternatively or additionally, the road sign can indicate a route section with potential danger, for example serpentines, which can have a negative effect on vehicle stability when the motor vehicle is driving at a high speed, which is higher than a speed dependent on the route section. A plurality of vehicle stability-related information is preferably evaluated, that is to say the determination of the vehicle stability information is based on a plurality of vehicle stability-related information that is provided for this purpose. The road sign information is only an example of the vehicle stability related information.

If the determined vehicle stability information is in a value range that is assigned to the vehicle instability, a notification message is provided for a driver of the motor vehicle. The range of values is a predetermined range of vehicle stability information within which the vehicle stability information lies if vehicle instability is present. In particular, it can be provided that a check is made as to whether the determined vehicle stability information is less than a vehicle stability limit value if the vehicle stability information assumes small values in the case of vehicle instability and larger values in the case of vehicle stability. As an alternative to this, provision can be made for a check to be carried out to determine whether the determined vehicle stability information is greater than or equal to the vehicle stability limit value if the vehicle stability information assumes small values for vehicle stability and larger values for vehicle instability. If the ascertained vehicle stability information is within the range of values, the information message is output, for example, by means of an output device in the motor vehicle. It can be provided that at least before the notification message is output, a check is made as to whether a driving speed of the motor vehicle is greater than a limit driving speed. It is therefore checked whether a piece of driving speed information describing the driving speed is lower than a piece of limiting driving speed information describing the limiting driving speed. Only if this is the case is the information message output, for example. In this way it can be achieved that, for example at a driving speed of 30 kilometers per hour, no information message is provided despite, for example, the detected road sign pointing to the uneven roadway, since in this case the occurrence of vehicle instability is not to be expected. The limit driving speed is preferably dependent on the vehicle stability-related information on which the ascertained vehicle stability information is based.

The output device can have a display device, in particular a screen or touch-sensitive screen, and/or a loudspeaker device which has at least one loudspeaker. The information message can therefore be provided acoustically and/or optically, for example. The output device can be a component of the motor vehicle. Alternatively or additionally, the information message can be provided by means of a mobile terminal device arranged in the motor vehicle, such as a smartphone and/or tablet, which is arranged in the motor vehicle and can have the display device and/or the loudspeaker device.

The advisory message describes at least one measure to reduce vehicle instability. The at least one measure relates to at least one activation of the longitudinal guide of the motor vehicle. In particular, it can be provided that the measure relates to a reduction in the driving speed of the motor vehicle, that is to say proposes a reduction in the driving speed of the motor vehicle. The information message thus advises the driver of the motor vehicle, for example, to reduce a speed at which the motor vehicle is traveling, ie the driving speed of the motor vehicle. For this purpose, the information message can, for example, name a specific target driving speed value to which the current driving speed should be reduced. As an alternative or in addition to this, the information message can be kept general, that is to say, for example, merely indicate that the driving speed should be reduced. Whenever it can be concluded from the ascertained vehicle stability information that vehicle instability has occurred for the motor vehicle, the information message is first provided in the motor vehicle and, in particular, output.

In the case of road sign information as vehicle stability-related information, for example, the road sign information can be evaluated tet and the advisory message are provided based on that the road sign indicates a rough road according to the road sign information. In this example, the street sign is assigned to the street on which the motor vehicle is currently driving. The value range can, for example, include a partial range between 0 and 1, for example the value range between 0 and 0.5. The vehicle stability information based on the road sign information can result in vehicle stability information of 0.3, for example, so that in this example the determined vehicle stability information is in the value range. So in this example the notification message would be provided. However, it can be provided that, for example, the driving speed is checked before the warning message is issued, so that the warning message is only actually issued at driving speeds of greater than or equal to 50 kilometers per hour, and no warning message is sent to the driver at driving speeds of less than 50 kilometers per hour driver is issued.

In a further method step, a check is carried out as to whether the driver has at least partially carried out the at least one measure. The at least one action is the action according to the notification message. It can therefore be checked, for example, whether the driving speed of the motor vehicle has actually been reduced if the driving speed should be reduced according to the measure that was described by the notification message. As an alternative or in addition to this, a predefined time window can be taken into account during the check, in which the driver is expected to react to the information message. The time window can, for example, have a duration of 1 second, 3 seconds, 5 seconds, 10 seconds, 30 seconds or 1 minute. Provision can then be made for the checking to be negative if the driver has not acted at least partially on the longitudinal guidance of the motor vehicle in accordance with the proposed measure in the time window. Alternatively or additionally, provision can be made for the vehicle stability information to continue to be ascertained, for example independently of the time window. If the vehicle stability information ascertained here is still smaller than the previously ascertained vehicle stability information, that is to say indicates increasing vehicle instability, the checking is negative. If the check is negative, it is assumed that the driver has not even partially carried out the at least one measure. Furthermore, the measure taken by the driver can be regarded as insufficiently implemented if, for example, there was a reduction in the driving speed of the motor vehicle, but this is less than a minimum driving speed reduction that is required in order to be able to counteract the vehicle instability in such a way that vehicle stability can be achieved is or will be achieved.

If the check found that the driver has not at least partially carried out the at least one measure, an automatic control intervention is carried out to reduce the vehicle instability. The control intervention affects at least the longitudinal guidance of the motor vehicle. In particular, it can be provided that the automatic control intervention relates to the reduction in the driving speed of the motor vehicle, that is to say that the motor vehicle is braked automatically. The automatic control intervention consequently relates to a braking system of the motor vehicle which has at least one brake, for example a hydraulic and/or electric brake. The automatic control intervention can therefore specify a braking acceleration for the motor vehicle, for example.

Ultimately, a two-stage contribution is made to reducing vehicle instability, first by notifying the driver and, if this has not yet led to the desired result, by subsequent automatic control intervention. It is assumed here that the measure according to the information message or the control intervention can contribute to at least reducing the vehicle instability and in particular to restoring vehicle stability.

The method steps described can be carried out using a control device of the motor vehicle. The control device is designed at least to control the longitudinal guide of the motor vehicle. The vehicle stability information is determined, the checks mentioned and the automatic control intervention is carried out, for example, by means of the control device. The control device can also be provided with the at least one piece of vehicle stability-related information, for example from another component of the motor vehicle, such as the sensor device. The overall result is that the vehicle stability of the motor vehicle is reliably detected and reduced. Since the control device of the motor vehicle, which is typically provided in a motor vehicle, can be used for this purpose, no additional hardware is required in the motor vehicle.

An advantageous exemplary embodiment provides that road sign information and/or weather information is provided as vehicle stability-related information. The road sign information describes a road sign. The Road sign specifically indicates an uneven road surface. The road sign can also be a sign indicating special features of the road surface, such as ruts in the road surface. The weather information describes weather in an area surrounding the motor vehicle. The environment of the motor vehicle is defined, for example, by a detection range of a sensor device of the motor vehicle, such as a camera. The weather information describes in particular rain, ice and/or snow. The weather information can therefore be determined, for example, by means of a rain sensor, a temperature sensor and/or a windshield wiper activation device, which always provides a signal when a windshield wiper of the motor vehicle is activated. The weather information is preferably based on an evaluation of measurement data from the sensors or device mentioned by way of example, that is to say for example the rain sensor and/or the windshield wiper activation device and the temperature sensor. The weather information is useful because, for example, there may be greater vehicle instability in ice and/or snow compared to a comparable situation without ice and/or snow.

The weather information and/or the street sign information can be provided to the motor vehicle and thus, for example, to the control device of the motor vehicle via a communication link, for example from an external computing device such as a server or backend, and/or from another road user, such as another motor vehicle in the area environment of the motor vehicle. Vehicle-to-vehicle communication or vehicle-to-infrastructure communication can be used for this. The weather information and/or the road sign information can therefore be transmitted wirelessly, in particular wirelessly, to the motor vehicle and received by it.

Ultimately, the surroundings of the motor vehicle are thus reliably examined for possible indications of an uneven roadway and/or weather conditions that may be unfavorable for the vehicle stability, and the vehicle instability that may be associated therewith is taken into account.

An additional exemplary embodiment provides that, if according to the road sign information there is an uneven road ahead of the motor vehicle in the direction of travel, driving speed information that describes the driving speed of the motor vehicle is recorded. The driving speed information can be determined, for example, by means of a speed sensor, an acceleration sensor and/or a device for determining a driving speed of the motor vehicle from sensor data recorded by the motor vehicle. A check is made as to whether the recorded driving speed information is greater than a driving speed limit value. The driving speed limit value can be specified explicitly for the case that a road sign indicates an uneven roadway, that is to say the driving speed limit value can be provided specifically for an uneven roadway. If the recorded driving speed information is greater than the driving speed limit value, the notification message is provided independently of the ascertained vehicle stability information. It is therefore possible in this case for the information message to reduce the speed to be provided even before the vehicle instability is actually reached, for example when driving on the uneven roadway. The reason for this is that even if the road sign information is available, which is typically located in front of the actual stretch of road with the uneven road surface, it can be concluded that vehicle instability is likely to occur, so that the information message can now be issued particularly early in this regard means the driver of the motor vehicle is warned of the vehicle instability that may follow. This provides a particularly anticipatory method for reducing vehicle instability. It can be provided, for example, that at a driving speed of, for example, 210 kilometers per hour and the road sign that refers to the uneven roadway is recognized, the warning message that is issued informs the driver that he should reduce the driving speed to, for example, less than 160 kilometers per hour should.

Furthermore, an exemplary embodiment provides that vehicle suspension information is provided as vehicle stability-related information. The vehicle suspension information describes a spring movement of a suspension of the motor vehicle. The vehicle suspension information can be provided, for example, by means of a suspension sensor, ie a sensor in the suspension of the motor vehicle. It can be taken into account here whether the suspension is based on air suspension, gas pressure suspension, liquid suspension or some other type of suspension. Finally, a pressure in the suspension of the motor vehicle can be detected, based on which the vehicle suspension information can be quantified. When determining the vehicle stability information, it is evaluated whether the suspension according to the vehicle suspension information has an amplitude that is greater than an ampli hour limit is moved. In this case, the amplitude is quantified using amplitude information, so that it is ultimately checked whether the amplitude information is greater than the amplitude limit value. Alternatively or additionally, it can be evaluated whether the suspension moves according to the vehicle suspension information at a speed that is greater than a speed limit value. The speed of the suspension may alternatively be referred to as the suspension speed and the speed limit as the suspension speed limit. Here, speed information relating to the movement of the suspension of the motor vehicle can be detected, with a check being made as to whether the speed information detected is greater than the speed limit value. In other words, it is checked whether it is observed for the motor vehicle while driving that the suspension of the motor vehicle moves strongly in a short time, i.e. at a speed greater than the speed limit value, and/or the movements of the suspension are becoming stronger, i.e. the amplitude is greater than the amplitude limit value. This behavior of the suspension is then considered an indication that the vehicle instability is building up, so that the vehicle suspension information can be taken into account as vehicle stability-related information when determining the vehicle stability information. This provides a particularly meaningful indication of possible vehicle instability.

A further exemplary embodiment provides that vibration information is provided as vehicle stability-related information. The vibration information describes a vibration of the motor vehicle. The vibration information can be determined, for example, using a 3G sensor that can detect accelerations in all three spatial directions. As an alternative or in addition to this, vehicle lateral acceleration information which describes a lateral acceleration of the motor vehicle can be provided as vehicle stability-related information. This can also be recorded using the 3g sensor. When determining the vehicle stability information, the determined vibration information is evaluated, wherein it is evaluated whether the vibration increases according to the vibration information. When ascertaining the vehicle stability information, the ascertained vehicle lateral acceleration information is alternatively or additionally evaluated, with it being evaluated in particular whether the lateral acceleration is increasing according to the vehicle lateral acceleration information. In other words, it is checked whether vibrations and/or transverse accelerations are detected in the motor vehicle, which are becoming stronger and stronger over time. In particular, it can be checked here whether the vibrations according to the vibration information are greater than a vibration limit value and/or the lateral acceleration according to the vehicle lateral acceleration information is greater than a lateral acceleration limit value. If this is the case, vehicle instability can be assumed, so that another reliable indication of possible vehicle instability can be taken into account.

An additional exemplary embodiment provides that steering movement information, which describes a steering movement by the driver of the motor vehicle, is provided as vehicle stability-related information. The steering movement information can be provided, for example, by means of a steering angle sensor that is arranged on the steering wheel of the motor vehicle. The steering angle sensor can, for example, detect a movement of the steering wheel. When determining the vehicle stability information, provided steering movement information is evaluated to the effect of whether a deflection of the steering movement is greater than a deflection limit value. In other words, deflection information that describes the deflection of the steering movement is considered and a check is made as to whether the deflection information is greater than the deflection limit value. As an alternative or in addition to this, it is determined during the evaluation whether a movement speed of the steering movement, ie a steering movement speed, is greater than a movement speed limit value. In other words, a piece of movement speed information which describes the movement speed of the steering movement is ascertained and checked as to whether this is greater than the movement speed limit value. In other words, the driver's steering movement is monitored to determine whether it changes from, for example, an initial steering movement to a comparatively larger and larger steering movement. As an alternative or in addition to this, it can be checked whether the steering movement changes from one of the initial steering movements to a steering movement that takes place more and more quickly in comparison thereto. The deflection limit value and/or the movement speed limit value can be specified as a function of a deflection of the steering movement or a movement speed of the steering movement in the case of driving stability, for example as the mean value of a hitherto typical steering movement by the driver over a distance of, for example, 10 meters up to 1 kilometer in front of a location where the vehicle instability has occurred. It is therefore ultimately checked whether the driver of the motor vehicle is starting or is already doing it, relatively strongly and/or hectically by steering movements, for example swinging the motor vehicle back and forth in a direction transverse to a direction of travel of the motor vehicle, as this is indicative of the vehicle instability. As an alternative or in addition to this, the steering movement can be an indication that the driver is being influenced to a correspondingly great extent by the bumps and that the rapid, short steering movements result from this, which in turn can lead to vehicle instability or can intensify it. As a result, another useful indicator for detecting the vehicle instability is provided.

In a particularly preferred exemplary embodiment, it is provided that trailer information is provided as vehicle stability-related information. The trailer information describes that a trailer is coupled to the motor vehicle. In this case, the motor vehicle can have a trailer detection sensor, for example, which is arranged in the rear area of the motor vehicle. The trailer detection sensor is designed to determine whether or not a trailer is connected to the motor vehicle. The trailer detection sensor thus detects the trailer coupled to the motor vehicle.

As an alternative or in addition to this, relative movement information can be provided as vehicle stability-related information. The relative movement information describes a relative movement of a rear area of the motor vehicle to a front area of the motor vehicle. The relative movement information can be recorded and evaluated independently of a coupled trailer in order to be able to act as an indication of the vehicle's instability. Overloading of the rear area can, for example, produce the inequality of the transverse movement between the front area and the rear area, which is described by means of the recorded relative movement information. A trailer can exacerbate this situation even further and, for example, lead to greater relative movement information than in a motor vehicle without a trailer. The relative movement information can be determined, for example, by means of local movement sensors or acceleration sensors in the motor vehicle, which are arranged, for example, both in the front area and in the rear area of the motor vehicle. In other words, a movement of the rear area or a rear wheel axle of the motor vehicle is determined in relation to an area of a front area or a front wheel axle of the motor vehicle. When determining the vehicle stability information, the determined relative movement information is evaluated to the effect of whether the relative movement information is greater than a relative movement limit value. It is therefore checked whether the relative movement between the rear area and the front area indicates vehicle instability or not because the relative movement limit value has been exceeded. Since a vehicle and trailer combination are particularly susceptible to vehicle instability, checking whether the trailer is coupled is particularly useful.

If the trailer is present according to the trailer information, for example, it can be provided that, for example, the value range, in particular the vehicle stability limit value, the deflection limit value, the movement speed limit value, the vibration limit value, the amplitude limit value, the speed limit value and/or the driving speed limit value, assume different values than in the motor vehicle without a trailer. It can therefore be taken into account that, for example, the vibration of the motor vehicle or the driver's steering movement can behave differently when the motor vehicle is driving with a trailer than when the motor vehicle is driving without a trailer. Ultimately, for the various limit values mentioned, a distinction can be made between a motor vehicle with a trailer and a motor vehicle without a trailer.

A further exemplary embodiment provides that if the trailer is coupled to the motor vehicle and the determined vehicle stability information is within the range of values, a rear camera of the motor vehicle is activated. Camera data recorded by means of the rear camera, in other words recorded rear camera data, can be made available by means of a display device in the motor vehicle. The display device is, for example, the screen of the motor vehicle and/or a screen of the mobile terminal device that is arranged in the motor vehicle. The camera data at least partially describes at least a portion of the trailer. In other words, a reversing camera, ie the rear camera, can be activated in order to visually evaluate the current situation of the trailer and, if necessary, to display it in the infotainment system, ie by means of the display device in the motor vehicle. The display obtained in this way, which shows at least a section of the trailer on the motor vehicle, can help the driver to assess how much the vehicle instability affects the movement of the trailer relative to the motor vehicle and/or to the road on which the combination of motor vehicle and trailer is driving , affects. As a result, the driver is further supported, for example, in implementing the measures according to the notification, since he is provided with visual information from his rear area, which at least partially shows the trailer, without looking into a mirror of the motor vehicle. This is particularly convenient for the driver.

It can also be provided that in an embodiment in which the trailer is coupled to the motor vehicle, the measure provides for an acceleration of the motor vehicle with an acceleration value according to the notification message provided. This is always the case when the motor vehicle is driving as a trailer with the trailer, this being provided on the basis of the trailer information. In addition, the control intervention in this case will initially provide for the acceleration by the acceleration value. Only then can the control intervention, for example, provide for reducing the driving speed of the motor vehicle. In other words, the driver is informed that he should at least temporarily increase the driving speed, for example to restore a voltage that has built up between the motor vehicle and the trailer, whereby a stable position of the trailer can be restored. If the measure according to the information message is not complied with, the automatic control intervention can take place by means of the control device, which initially also provides for an acceleration. The acceleration can be referred to as emergency acceleration. Thereupon, ie after the acceleration, it makes sense and is necessary to slowly slow down the combination of motor vehicle and trailer again, for example in order to reduce the driving speed to a predetermined maximum driving speed and to prevent future vehicle instability. The predefined maximum driving speed can be a maximum speed prescribed for the route section.

For the motor vehicle without a trailer, the advisory message should advise the driver to reduce speed immediately. If he does not comply with this recommendation and the motor vehicle has continued to rock in the meantime, for example, i.e. if checking whether the driver has carried out at least one measure at least partially is unsuccessful, an emergency deceleration is initiated via the automatic control intervention, that is, emergency braking to stabilize the unstable motor vehicle again. As an alternative to this, it can be provided that the acceleration of the motor vehicle is at least temporarily suspended, ie the motor vehicle is neither accelerated nor braked. This can be useful, for example, when aquaplaning is detected, so that the automatic control intervention can include stopping the acceleration, ie allowing the motor vehicle to coast at least temporarily. The automatic control intervention is preferably dependent on the weather, i.e. it takes into account the weather information, since, for example, a required intervention to reduce the driving speed in rain and/or ice can be quantified differently than, for example, in comparatively dry and ice-free weather.

It can also be provided that not only the longitudinal guidance of the motor vehicle is affected by the measure according to the information message and/or the automatic control intervention, but also a lateral guidance of the motor vehicle. For this purpose, the measure can relate to steering information or the control intervention can relate to the steering of the motor vehicle. The method according to the invention can be implemented by a driver assistance system of the motor vehicle, ie it can be integrated into a driver assistance system.

Information within the meaning of the invention can be described using data. For example, the ascertained vehicle stability information can be in the form of vehicle stability data. Similarly, the other information mentioned can each be expressed as corresponding data. For example, road sign data, weather data, driving speed data, vehicle suspension data, amplitude data, speed data relating to the suspension, vibration data, steering movement data, deflection data, movement speed data, trailer data and/or relative movement data can be taken into account.

A further aspect of the invention relates to a motor vehicle which is designed to carry out the method according to the invention. The exemplary embodiments described in connection with the method, each individually and in combination with one another, apply correspondingly, to the extent applicable, to the motor vehicle according to the invention. The motor vehicle can be, for example, a passenger car, a truck, a bus and/or a motorcycle.

One aspect of the invention relates to the control device for the motor vehicle. The control device has a processor device which is set up to carry out the method according to the invention, an exemplary embodiment of the method or a combination of exemplary embodiments. For this purpose, the processor device can have at least one microprocessor and/or at least one microcontroller and/or at least one FPGA (Field Programmable Gate Array) and/or at least one DSP (Digital Signal Processor). Furthermore, the processor device can have program code which is set up to carry out the method according to the invention, the exemplary embodiment of the method or the combination of exemplary embodiments when executed by the processor device. The program code can be stored in a data memory of the processor device.

Another aspect of the invention relates to a computer program product, for example a computer program can be. The computer program product according to the invention comprises instructions which, when the program is executed by a computer, for example by the control device of the motor vehicle, cause the latter to carry out the method described above and one or more exemplary embodiments of the method according to the invention.

The motor vehicle and/or the control device carry out the method according to the invention.

The invention also includes the combinations of features of the described embodiments.

• 1 eine schematische Darstellung eines Kraftfahrzeugs, das auf einer Straße mit einer unebenen Fahrbahn fährt; und
• 2 in schematischer Darstellung einen Signalflussgraphen eines Verfahrens zum Reduzieren einer Fahrzeuginstabilität eines Kraftfahrzeugs.

Exemplary embodiments of the invention are described below. For this shows:

• 1 a schematic representation of a motor vehicle driving on a road with an uneven surface; and
• 2 a schematic representation of a signal flow graph of a method for reducing vehicle instability of a motor vehicle.

The exemplary embodiments explained below are preferred exemplary embodiments of the invention. In the exemplary embodiments, the described components each represent individual features of the invention to be considered independently of one another, which also develop the invention independently of one another and are therefore also to be regarded as part of the invention individually or in a combination other than that shown. Furthermore, the exemplary embodiments described can also be supplemented by further features of the invention already described.

Elements with the same function are each provided with the same reference symbols in the figures.

In 1 a motor vehicle 1 driving on a road 2 is outlined. The road 2 has several bumps, here as an example several potholes 4 and ruts 3. The ruts 3 are in a direction of travel 5 of the motor vehicle 1, whereas here, purely by way of example, the potholes 4 for a lane adjacent to the lane on which the motor vehicle 1 drives, are outlined. A road sign 6 is arranged at the beginning of or in front of the ruts 3, which can be embodied as a warning sign pointing out the uneven roadway. The roadway can be referred to as the driving surface. The road sign 6 can also be an information sign on which ruts 3 are explicitly mentioned. Such a sign can be designed as an additional sign to a traffic sign.

The motor vehicle 1 has a control device 7 . The control device 7 is a computing device, ie it has at least one microprocessor and/or microcontroller, for example. The control device 7 can be designed to control a longitudinal and/or lateral guidance of the motor vehicle 1, ie to accelerate, brake and/or steer the motor vehicle 1.

The motor vehicle 1 has a display device 8 which can be embodied as a screen, in particular as a touch-sensitive screen. In addition, the motor vehicle 1 has, for example, a loudspeaker device 9 which has at least one loudspeaker. Visual and/or acoustic information can thus be output in the motor vehicle 1 by means of the display device 8 or the loudspeaker device 9 .

The motor vehicle 1 can have a front camera 10, by means of which the street sign 6 can be detected, for example. As an alternative or in addition to this, the motor vehicle 1 can have a rear camera 11 which, for example, can capture an area behind the motor vehicle 1 .

Motor vehicle 1 may have additional sensors, for example a suspension sensor 12, a vibration sensor 13, a steering angle sensor 14, a temperature sensor 15, a rain sensor 16 and/or at least one acceleration sensor 17.

The motor vehicle 1 can have a communication interface 18 . The motor vehicle 1 can, for example, receive data from an external computing device 21, for example a server or a backend, via the communication interface 18. For this purpose, the external computing device 21 also has the communication interface 18, for example. A communication connection between the two communication interfaces 18 is preferably wireless, in particular wireless. The motor vehicle 1 can receive information about the current weather or about street signs 6 along a driving route of the motor vehicle 1 via the communication link, for example. As an alternative to the external computing device 21, the motor vehicle 1 can receive such information from another vehicle, in particular another motor vehicle 1.

The motor vehicle 1 may have a trailer detection sensor 19, by means of which it can be recognized whether the motor vehicle 1 is coupled to a trailer 20 . Here, purely by way of example, the motor vehicle 1 is coupled to the trailer 20 . However, the method described below is also suitable for a motor vehicle 1 without a trailer 20 coupled to motor vehicle 1.

In 2 a method for reducing a vehicle instability of the motor vehicle 1 is outlined. At least one item of information 22 relating to vehicle stability is provided in a method step S1. A number of vehicle stability-related items of information 22 are preferably provided and taken into account as part of the further method. Seven possible items of information 22 related to vehicle stability are outlined here as an example. The vehicle stability-related information 22 can be road sign information 23 captured by means of the front camera 10 , for example. The road sign information 23 describes the road sign 6, which indicates in particular an uneven road. Alternatively or additionally, the uneven roadway can be detected by means of the front camera 10 and thus camera information (not outlined here), which describes the uneven roadway, can be provided as vehicle stability-related information 22 . As an alternative or in addition to this, weather information 24 that describes the weather in an area surrounding motor vehicle 1, in particular rain, ice and/or snow, can be taken into account as vehicle stability-related information 22 . The weather information 24 can be determined, for example, by means of the temperature sensor 15 and/or the rain sensor 16 . In particular, the street sign information 23 and/or the weather information 24 can be provided by the external computing device 21 .

As an alternative or in addition to this, vehicle suspension information 25 can be taken into account as vehicle stability-related information 22 , which is determined, for example, by means of the suspension sensor 12 . Vehicle suspension information 25 describes a spring movement of a suspension of motor vehicle 1. Alternatively or additionally, vibration information 26 can be taken into account as vehicle stability-related information 22, which describes vibration of motor vehicle 1 and is determined, for example, using vibration sensor 13. As an alternative or in addition to this, steering movement information 27 that describes a steering movement by the driver of motor vehicle 1 can be taken into account as vehicle stability-related information 22 . The steering movement information 27 can be detected and determined using the steering angle sensor 14 . As an alternative or in addition to this, trailer information 28 which describes that the trailer 20 is coupled to the motor vehicle 1 can be taken into account as vehicle stability-related information 22 . The trailer information 28 can be determined and made available, for example, by means of the trailer detection sensor 19 . Alternatively or additionally, relative movement information 29 can be provided as vehicle stability-related information 22 , which describes a relative movement of a rear area of motor vehicle 1 to a front area, in particular a front wheel axle of motor vehicle 1 . The relative movement information 29 is determined, for example, on the basis of data from at least one and preferably a plurality of acceleration sensors 17 of the motor vehicle 1. In particular, the trailer information 28 and the relative movement information 29 are particularly useful in situations in which the motor vehicle 1 is driving with the trailer 20, i.e. in a combination of motor vehicle 1 and trailer 20. Alternatively or additionally, as vehicle stability-related information 22, lateral acceleration information that describes a lateral acceleration of the motor vehicle 1 and/or the trailer 20. The lateral acceleration information recorded by the trailer 20 can be transmitted from the trailer 20 to the motor vehicle 1 via a communication link. Lateral acceleration information can thus be available from the rear area and/or front area of motor vehicle 1 (detected by means of multiple acceleration sensors 17) and/or from the trailer.

Vehicle stability information 30 describing the vehicle stability of motor vehicle 1 is determined in a method step S2. This is done by evaluating at least one of the named items of information 22 related to vehicle stability, wherein preferably several of the named possible items of information 22 related to vehicle stability are evaluated. Evaluation-related peculiarities are to be mentioned with regard to the vehicle suspension information 25, the vibration information 26, the steering movement information 27 and the relative movement information 29. In the case of vehicle suspension information 25 , it must be taken into account that this can have amplitude information 31 , with the evaluation in method step S2 for determining vehicle stability information 30 checking whether amplitude information 31 is greater than an amplitude limit value 32 . As an alternative or in addition to this, the vehicle suspension information 25 can have speed information 33 , it being checked in method step S2 whether the speed information 33 is greater than a speed limit value 34 . If either of these two checks is successful, this can promote vehicle stability information 30 that indicates vehicle instability. Concerning the vibration information 26 can be checked to see whether it is greater than a vibration limit value 35 . In particular, it is checked whether the vibration according to the vibration information 26 increases over time, which in turn can indicate vehicle instability. When vehicle stability information 30 is determined, it is therefore evaluated whether the vibration is increasing and in particular whether vibration information 26 is greater than vibration limit value 35 . With regard to steering movement information 27, when determining vehicle stability information 30, an evaluation is made as to whether deflection information 36, which describes a deflection of the steering movement of the steering wheel, is greater than a deflection limit value 37 and/or whether movement speed information 38, which describes a movement speed of the steering movement of the steering wheel, is greater is 39 as a moving speed limit. It can also be provided in connection with the relative movement information 29 that when determining the vehicle stability information 30 it is evaluated whether the relative movement information 29 is greater than a relative movement limit value 40 . Ultimately, method step S2 calculates a value, specifically vehicle stability information 30, which indicates either vehicle stability or vehicle instability. A combination of the various possible items of information 22 related to vehicle stability is therefore carried out in order to be able to evaluate the vehicle stability. Method step S2 is preferably carried out using control device 7 of motor vehicle 1 .

In a method step S3, a check is made as to whether determined vehicle stability information 30 is in a value range that is assigned to the vehicle instability. Provision is made here, for example, for a check to be made as to whether ascertained vehicle stability information 30 is less than a vehicle stability limit value 41 . As an alternative to this, it could be checked whether determined vehicle stability information 30 is greater than or equal to vehicle stability limit value 41 . If the check in method step S3 is successful, a message 42 is provided for the driver of motor vehicle 1 in method step S4. Message 42 can be provided optically by means of display device 8 and/or acoustically by means of loudspeaker device 9 in motor vehicle 1. The notification message 42 describes at least one measure for reducing the vehicle instability, the at least one measure relating at least to the actuation of the longitudinal guidance of the motor vehicle 1 . The notification message 42 can be selected taking into account the information from method step S1. Notification message 42 preferably relates to a reduction in the driving speed of motor vehicle 1. If trailer 20 is coupled, the measure according to notification message 42 can initially provide for acceleration of motor vehicle 1 by an acceleration value, for example by a distance between motor vehicle 1 and trailer 20 to enlarge.

Provision can be made for a check to be carried out, at least before the notification message 42 is output, for example in method step S3, as to whether a current driving speed of the motor vehicle 1 is greater than a limit driving speed. It is therefore checked whether a piece of driving speed information 44 describing the driving speed is less than a driving speed limit value 45 describing the limiting driving speed. The notification message 42 is actually output only if this is the case.

If it is determined in method step S3 that vehicle stability information 30 is not in the value range, i.e. greater than or equal to vehicle stability limit value 41 here, for example, method step S1 or, alternatively, method step S2 can be carried out again.

In a method step S5, a check is made as to whether the driver has at least partially carried out the at least one measure according to notification message 42 . When checking, for example, a time window and/or changing vehicle stability information 30, which is always smaller than vehicle stability limit value 41, for example, can be taken into account. If the driver has carried out the at least one measure according to notification message 42, the method can be ended in a method step S6. The process can then be restarted.

If the driver has not at least partially carried out the at least one measure according to the notification message 42, an automatic control intervention 43 for reducing the vehicle instability can be carried out in a method step S7. The control intervention 43 relates at least to the longitudinal guidance of the motor vehicle 1 and leads in particular to a reduction in the driving speed of the motor vehicle 1. In the case of the combination of motor vehicle 1 and trailer 20, the automatic control intervention 43 can first provide for the acceleration and then the reduction in the driving speed of the motor vehicle 1. The information from method step S1 can be taken into account for the control intervention 43 . They can be taken into account for the execution and/or for the selection of an intensity of the execution of the control intervention 43 .

If it is determined in a method step S8 that according to the road sign information 23 there is an uneven roadway or a roadway with ruts 3 in the direction of travel 5 in front of the motor vehicle 1, in a method step S9 a driving speed information item 44 that describes the driving speed of the motor vehicle 1 can be determined. The information from method step S1 can be taken into account. Driving speed information 44 can be determined, for example, by means of a speed sensor or acceleration sensor 17 of motor vehicle 1 . In a method step S10, it is then checked whether the recorded driving speed information 44 is greater than a driving speed limit value 45. Driving speed limit value 45 can be specified as a function of road sign information 23 and/or, for example, information about a type of road on which motor vehicle 1 is driving. The road type can distinguish, for example, between an expressway, a country road or an inner-city road 2 . If the check is successful, that is, if the driving speed information 44 is greater than the driving speed limit value 45, the notification message 42 can be provided independently of the ascertained vehicle stability information 30, that is to say method step S4 takes place.

Provision can furthermore be made for camera data 46 to be recorded in a method step S11 by means of a rear camera 11 of motor vehicle 1, which can alternatively be referred to as rear camera data. The camera data 46 at least partially describe at least a part of the trailer 20. They can therefore at least partially show the trailer 20 of the motor vehicle 1, in which case they do not have to show the trailer 20 in full. The camera data 46 can be made available by means of the display device 8 in the motor vehicle 1, that is to say can be displayed, for example. Method step S11 preferably takes place whenever determined vehicle stability information 30 is in the value range, ie after method step S3, and only if trailer 20 is coupled to motor vehicle 1.

All method steps can be carried out by means of the control device 7 or at least initiated by the control device 7, that is to say they can take place in response to control commands from the control device 7 .

Overall, the examples show an anti-snaking assistant for the motor vehicle 1. The method is characterized first by determining the vehicle stability, i.e. by determining the vehicle stability information 30. For this purpose, checking the signs for warnings about unevenness, checking the change in suspension travel, checking changing steering movements, checking for attached trailers 20 and/or checking for movement of the rear area in relation to the front wheel axle, ie to the front area. This data is then evaluated by a control unit of motor vehicle 1, that is to say by control device 7. Information is then output to the driver for initiating the measure in the form of notification message 42. Even before the unstable driving situation, the driver can be asked to slow down at high speeds and recognized signs, as provided for in method steps S8 to S10. Furthermore, in the event of non-compliance, the initiation of measures is taken over by a driver assistance system, that is to say by the automatic control intervention 43 for restoring vehicle stability. As a result, a speed can be reduced or, in the case of a trailer combination, the speed, ie the acceleration, can be increased for a short time.

Reference List

1

motor vehicle

2

Street

3

rut

4

pothole

5

driving direction

6

street sign

7

control device

8th

display device

9

speaker setup

10

front camera

11

rear camera

12

suspension sensor

13

vibration sensor

14

steering angle sensor

15

temperature sensor

16

rain sensor

17

accelerometer

18

communication interface

19

trailer detection sensor

20

Trailer

21

computing device

22

vehicle stability related information

23

road sign information

24

weather information

25

Vehicle Suspension Information

26

vibration information

27

steering movement information

28

trailer information

29

relative motion information

30

Vehicle Stability Information

31

amplitude information

32

amplitude limit

33

speed information

34

speed limit

35

Vibration Limit

36

deflection information

37

Deflection Limit

38

movement speed information

39

movement speed limit

40

relative motion limit

41

Vehicle Stability Limit

42

Advisory message

43

Automatic control intervention

44

driving speed information

45

vehicle speed limit

46

camera data

S1 - S12

process steps

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102012219721 A1 [0003]
• DE 102010045162 A1 [0004]
• DE 102014226897 A1 [0005]

Claims (10)

Method for reducing vehicle instability of a motor vehicle (1), the method comprising the following steps: - determining (S2) vehicle stability information (30) which describes the vehicle stability of the motor vehicle (1) by evaluating at least one vehicle stability-related information (22); - if the determined vehicle stability information (30) is in a value range that is assigned to the vehicle instability (S3), providing (S4) an information message (42) for a driver of the motor vehicle (1), which describes at least one measure for reducing the vehicle instability, wherein the at least one measure relates to at least one actuation of a longitudinal guide of the motor vehicle (1), in particular a reduction in a driving speed of the motor vehicle (1); - Checking (S5) whether the driver has at least partially carried out the at least one measure; and - if the driver has not at least partially carried out the at least one measure, carrying out (S7) an automatic control intervention (43) to reduce the vehicle instability, the control intervention (43) affecting at least the longitudinal guidance of the motor vehicle (1), in particular the reduction of the driving speed of the motor vehicle (1). procedure after claim 1 , wherein, as vehicle stability-related information (22), road sign information (23) that describes a road sign (6) that particularly indicates an uneven roadway, on the one hand and/or weather information (24) that describes the weather in the vicinity of the motor vehicle (1st ) describes, in particular rain, ice and/or snow, on the other hand. Procedure according to the first alternative of claim 2 , wherein, if according to the road sign information (23) there is an uneven roadway in the direction of travel (5) in front of the motor vehicle (1), driving speed information (44), which describes the driving speed of the motor vehicle (1), is recorded (S9) and checked ( S10) whether the recorded driving speed information (44) is greater than a driving speed limit value (45), and if this is the case, the notification message (42) is provided independently of the determined vehicle stability information (30). Method according to one of the preceding claims, wherein vehicle suspension information (25) which describes a spring movement of a suspension of the motor vehicle (1) is provided as vehicle stability-related information (22) and when determining the vehicle stability information (30) it is evaluated whether the suspension is moving according to the vehicle suspension information (25) moves at an amplitude greater than an amplitude limit (32) and/or at a speed greater than a speed limit (34). Method according to one of the preceding claims, wherein vibration information (26) which describes a vibration of the motor vehicle (1) is provided as vehicle stability-related information (22) and when determining the vehicle stability information (30) it is evaluated whether the vibration according to the vibration information ( 26) increases, in particular is greater than a vibration limit value (35). Method according to one of the preceding claims, wherein steering movement information (27) which describes a steering movement by the driver of the motor vehicle (1) is provided as vehicle stability-related information (22), and when determining the vehicle stability information (30) it is evaluated whether a deflection of the steering movement is greater than a deflection limit value (37) and/or whether a movement speed of the steering movement is greater than a movement speed limit value (39). Method according to one of the preceding claims, wherein trailer information (28) describing that a trailer (20) is coupled to the motor vehicle (1) is provided as vehicle stability-related information (22) and/or relative movement information (29) which describes a relative movement of a rear area of the motor vehicle (1) to a front area of the motor vehicle (1), provided and when determining the vehicle stability information (30) it is evaluated whether the relative movement information (29) is greater than a relative movement limit value (40). Method according to one of the preceding claims, wherein, if a trailer (20) is coupled to the motor vehicle (1) and the determined vehicle stability information (30) is in the value range, a rear camera (11) of the motor vehicle (1) is activated and by means of the rear camera ( 11) recorded camera data (46), which at least partially describe at least part of the trailer (20), are made available by means of a display device (8) in the motor vehicle (1). Method according to one of the preceding claims, wherein, if a trailer (20) is coupled to the motor vehicle (1), the measure according to the information message (42) provided involves accelerating the motor vehicle (1) by an acceleration value and the control intervention (43 ) first the acceleration around the Acceleration value and then the reduction of the driving speed of the motor vehicle (1) provides. Motor vehicle (1) designed to carry out a method according to one of the preceding claims.

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