DE102008010667B4 - Method and device for assisting a vehicle operator - Google Patents

Abstract

Method for supporting a vehicle operator in driving a vehicle (100), in which a critical driving situation is recognized using recorded environmental data, whereupon at least one safety measure is carried out with the aim of preventing a collision with a detected environmental object (112). and/or to reduce the consequences of a collision with a detected environmental object (112) for the vehicle operator and in which at least one assistance function (202; 204; 206) is activated, which assists the vehicle operator in driving the vehicle (100) after the critical driving situation has ended ) is supported, wherein - the distance control (202) and / or the cornering speed control (204) are activated if the vehicle (100) is in motion when the safety measure is ended, and - the assistance function is a holding function (206) that Keeps the vehicle (100) at a standstill by actuating a brake system, the holding function (206) being activated if the vehicle (100) is at a standstill when the safety measure is ended.

Description

Technical area

The invention relates to electronically controlled support for a vehicle operator in connection with a critical driving situation, in particular after a critical driving situation. In particular, the invention relates to a method for supporting a vehicle operator and a device suitable for carrying out the method.

Background of the invention

For example in the international patent application WO 2004/ 085 220 A1 A system for recognizing critical driving situations and for carrying out collision-avoiding and collision-reducing safety measures in a motor vehicle is described. To record traffic events, such systems have an environmental sensor system with which objects in the area surrounding the vehicle, in particular other vehicles, are detected. Based on the surrounding data, a hazard calculator determines the risk potential of the driving situation, which corresponds to the probability of a collision. The safety measures are then carried out depending on the risk potential.

The security measures provided are usually tiered. If the risk potential is lower, warnings can be issued to the driver to alert them to a potentially dangerous driving situation. If there is a higher risk potential, automatic braking maneuvers or evasive maneuvers can be planned. Further safety measures include, for example, tightening vehicle occupants' seat belts, improving the seating position of vehicle occupants and preconditioning restraints, such as airbags or pyrotechnic belt tensioners, so that they are triggered more quickly in the event of a collision.

As a rule, driver support is provided by the safety system until the critical driving situation has ended. However, after a critical driving situation has ended, the driver is often indisposed due to the danger that has just been overcome and is initially unable to drive the vehicle safely. This can create a new dangerous situation.

Furthermore, it describes US 2004 / 0 155 811 A1 a driver assistance system for a motor vehicle, in which detector devices are used to determine the relative distance and relative speed of a motor vehicle in relation to a stationary or moving obstacle in front of it. Furthermore, automatic emergency braking of the motor vehicle is effected when the relative distance between the motor vehicle and an obstacle ahead is between a minimum value at which a collision can still be avoided by braking and a preselected intermediate value which is between the minimum value and a second limit value. is, whereby the second limit value is smaller than the minimum value and equal to the minimum relative distance at which it is still possible to follow an avoidance route around the obstacle, or the relative distance is smaller than the second limit value.

Out of DE 10 2004 055 399 A1 a method and a device for controlling a vehicle are known, wherein in the event of a collision of the vehicle, this is automatically braked by actuating a brake of the vehicle, a collision being identified if an ignited airbag of the vehicle is identified and / or if for a deceleration of the vehicle a first limit value is exceeded.

The DE 10 2004 058 663 A1 is a method and device for controlling automatic emergency braking of a motor vehicle, wherein the position and/or speed of an object relative to one's own vehicle are detected by means of an object detection device and are fed to a collision detection device which determines whether a collision with the object is imminent and when a collision is detected, emergency braking is triggered and a collision time is determined, with the emergency braking being terminated after the time period up to the determined collision time has elapsed.

A method for influencing the stress on a driver while driving a motor vehicle is also from the DE 103 22 458 A1 known, in which a stress value is determined from the driver's physiological data recorded by sensors and a dangerous situation is recognized based on the stress value and, as a result, intervention is made in the vehicle control.

Further revealed DE 10 2005 024 558 A1 a method for determining the geometry of a route section, in which to determine a maximum possible speed for a vehicle traveling on the route section, using information about route points representing the route section, route section data being calculated between at least three adjacent route points.

Presentation of the invention

It is therefore an object of the present invention to increase vehicle safety after a critical driving situation has ended.

According to the invention, this object is achieved by a method with the features of patent claim 1 and by a device with features of patent claim 9. Embodiments of the method and the device are specified in the dependent claims.

• -bei dem unter Heranziehung von erfassten Umfelddaten eine kritische Fahrsituation erkannt wird, woraufhin
• -wenigstens eine Sicherheitsmaßnahme mit dem Ziel ausgeführt wird, eine Kollision mit einem erfassten Umfeldobjekt zu verhindern und/oder Folgen einer Kollision mit einem erfassten Umfeldobjekt für den Fahrzeugbediener zu verringern und bei dem
• -wenigstens eine Assistenzfunktion aktiviert wird, die den Fahrzeugbediener nach Beendigung der kritischen Fahrsituation bei der Führung des Fahrzeugs unterstützt.

Accordingly, a method for supporting a vehicle operator in driving a vehicle is provided,

• -in which a critical driving situation is recognized using recorded environmental data, whereupon
• -at least one safety measure is carried out with the aim of preventing a collision with a detected environmental object and / or reducing the consequences of a collision with a detected environmental object for the vehicle operator and in which
• -At least one assistance function is activated, which supports the vehicle operator in driving the vehicle after the critical driving situation has ended.

• - ein Sicherheitssystem, das dazu ausgebildet ist, unter Heranziehung von erfassten Umfelddaten eine kritische Fahrsituation zu erkennen, und die Ausführung wenigstens einer Sicherheitsmaßnahme mit dem Ziel zu steuern, eine Kollision mit einem erfassten Umfeldobjekt zu verhindern und/oder Folgen einer Kollision mit einem erfassten Umfeldobjekt für den Fahrzeugbediener zu verringern und
• - wenigstens eine Steuereinheit zur Ausführung einer Assistenzfunktion, die den Fahrzeugbediener bei der Führung des Fahrzeugs unterstützt, wobei die Assistenzfunktion von dem Sicherheitssystem aktivierbar ist, so dass sie den Fahrzeugbediener nach Beendigung der kritischen Fahrsituation bei der Führung des Fahrzeugs unterstützt.

In addition, a device for supporting a vehicle operator in driving a vehicle is proposed. The device includes

• - a safety system that is designed to recognize a critical driving situation using recorded environmental data and to control the execution of at least one safety measure with the aim of preventing a collision with a detected environmental object and / or the consequences of a collision with a detected environmental object for the vehicle operator to reduce and
• - at least one control unit for executing an assistance function that supports the vehicle operator in driving the vehicle, the assistance function being able to be activated by the safety system so that it supports the vehicle operator in driving the vehicle after the critical driving situation has ended.

The invention includes the idea of activating at least one assistance function of the motor vehicle when a critical driving situation exists, which supports the vehicle operator after the critical driving situation has ended. This relieves the vehicle operator after the critical driving situation has ended, so that the probability of a new dangerous driving situation arising due to errors by the vehicle operator is reduced. This increases vehicle safety after the critical driving situation has ended.

A critical driving situation is understood to mean a driving situation with an increased risk potential for the safety of the vehicle operator and/or other vehicle occupants, in particular a driving situation with an increased probability of a collision between the vehicle and a surrounding object in the area surrounding the vehicle.

In one embodiment of the method and the device it is provided that the assistance function is activated after the security measure has been completed. In particular, it is provided that the assistance function to be activated is selected depending on a movement state of the vehicle after the safety measure has ended.

This ensures that the support provided by the assistance function can be adapted to the state of motion of the vehicle that exists after the safety measure has ended. For example, different assistance functions can be activated depending on whether the vehicle is moving or stationary after the safety measure has ended. The activation of the assistance function preferably takes place after the safety measure has ended.

One embodiment of the method and the device provides that the safety measure is ended when a predetermined period of time has passed since the start of the safety measure or when the risk potential of the driving situation has reduced to a predetermined extent.

In one embodiment of the method and the device, it is provided that the assistance function is a distance control that regulates a distance to a vehicle in front to a predetermined target value by regulating a speed of the vehicle.

In this embodiment, an assistance function is advantageously activated, which supports the driver in maintaining a sufficient distance from a vehicle in front. This prevents a collision from occurring after the critical driving situation has ended due to inattention on the part of the vehicle operator accident occurs. The distance to the vehicle in front is determined using environmental sensors. This is preferably the environmental sensor system, which is also used to record environmental data to detect the critical driving situation.

Furthermore, an embodiment of the method and the device is characterized in that the assistance function is a curve speed control that determines a curve to be traveled by the vehicle and sets a vehicle speed that is determined as a function of a radius of the curve.

In this embodiment, an assistance function is advantageously activated, which supports the driver in driving through a curve at a suitable speed. This in particular prevents the vehicle from skidding in a curve after the critical driving situation has ended if the vehicle operator does not brake the vehicle sufficiently due to inattention.

A related embodiment of the method and the device includes that the curve to be traveled is determined in accordance with a position of the vehicle determined by a positioning system using map data, and the curve radius is determined based on the map data.

This configuration has the advantage that a curve to be traveled and its radius can be determined very reliably using map data. The location system and the map data can be provided by a navigation system of the vehicle, which is networked with the assistance function for cornering speed control. The positioning system can be, for example, a satellite positioning system, in particular a GPS system (GPS: Global Positioning System).

A further embodiment of the method and the device provides that the curve is determined based on captured environmental data using lane detection, and the curve radius is determined based on the environmental data.

In this embodiment, the environmental sensors provided for detecting critical driving situations can advantageously be accessed in order to determine a curve to be traveled and its radius. So no additional systems need to be provided in the vehicle.

The previously described distance control and the cornering speed control support the vehicle operator in driving situations in which the vehicle is in motion, particularly in the forward direction. Therefore, the method and the device are characterized in that the distance control and/or the cornering speed control are activated if the vehicle is in motion when the safety measure is ended.

A development of the method and the device according to the invention includes that the assistance function is a holding function that keeps the vehicle at a standstill by actuating a brake system.

In this development, an assistance function is advantageously activated, which supports the vehicle operator in keeping the vehicle at a standstill if it has come to a standstill during the critical driving situation. This can happen, for example, if an automatic braking maneuver has been carried out as a safety measure. In particular, the assistance function prevents the vehicle from moving if the driver releases the brake or does not apply it due to inattention.

A related embodiment of the method and the device is characterized in that the holding function is activated if the vehicle is at a standstill when the safety measure is ended.

In addition, a computer program is provided which includes instructions for executing a method of the type described above on a processor.

The processor can be, for example, a microprocessor of a control unit of the vehicle. The computer program can, for example, be stored in a memory of this control unit. Likewise, the computer program can be provided on a data carrier, for example.

The aforementioned and other advantages, special features and useful developments of the invention are also clear from the exemplary embodiments, which are described below with reference to the figures.

Short description of the characters

• 1 eine schematische Blockdarstellung eines Kraftfahrzeugs mit einer erfindungsgemäßen Vorrichtung,
• 2 ein schematisches Ablaufdiagramm, in dem ein Verfahren zur Unterstützung des Fahrers nach Beendigung einer von einem Sicherheitssystem gesteuerten Sicherheitsmaßnahmen veranschaulicht wird und
• 3 ein schematisches Ablaufdiagramm zur Veranschaulichung einer Ausführungsform einer Haltefunktion.

Of the figures shows:

• 1 a schematic block diagram of a motor vehicle with a device according to the invention,
• 2 a schematic flow diagram illustrating a method for assisting the driver after completion of a safety measure controlled by a safety system and
• 3 a schematic flowchart to illustrate an embodiment of a holding function.

Detailed description of exemplary embodiments

In 1 a motor vehicle 100 is shown, which has a drive motor 101, which is controlled by the driver using an accelerator pedal 102. A drive torque provided by the drive motor 101 is transmitted via a drive train, not shown in the figure, to two or all four wheels 107VL, 107VR, 107HL, 107HR in order to drive the motor vehicle 100. The front wheels 107VL, 107VR of the motor vehicle 100 are designed to be steerable and are connected via a steering line 108 to a steering handle 109, with which the driver can change the wheel steering angle.

In one embodiment, the steering train 108 also has a steering actuator 120, which can be controlled by external signals. The steering actuator 120 enables interventions in the steering train 108, which can be used to specifically adjust a predetermined wheel steering angle of the front wheels 101vl, 101vr. The steering actuator 120 can, for example, be designed as a so-called superimposed steering system, which is known to those skilled in the art, which superimposes an additional steering angle on the wheel turning angle set by the driver, which is dimensioned such that the sum of both steering angles corresponds to the wheel turning angle to be set. Likewise, it can be provided that the steering train 108 is subjected to a torque by means of the steering actuator 120, which also acts on the steering handle 109. This makes it possible to carry out automatic steering movements or to cause or instruct the driver to carry out predetermined steering movements. In this embodiment, the steering actuator 120 can be designed, for example, as an electronic power steering.

In addition, the motor vehicle 100 has a service brake system, which is designed, for example, as a hydraulic brake system. The service brake system is actuated by the driver of the motor vehicle 100 using a brake pedal 103. Due to an actuation of the brake pedal 103, a brake pressure is built up in a master cylinder 104 via a brake booster, not shown in the figure. The brake pressure can be transmitted to the wheel brakes 106VL, 106VR, 106HL, 106HR via a hydraulic unit 105. Hydraulic lines are provided for this purpose, which for reasons of clarity are shown in 1 are not shown. The wheel brakes 106VL, 106VR, 106HL, 106HR attached to the wheels 107VL, 107VR, 107HL, 107HR include a vehicle-mounted brake piston which is pressed against a wheel-mounted brake disc when the wheel brakes 106VL, 106VR, 106HL, 106HR are pressurized, whereby a braking torque is generated.

The hydraulic unit 105 includes a valve arrangement and at least one pressure source for automatically adjusting the brake pressure in the wheel brakes 106VL, 106VR, 106HL, 106HR. Such hydraulic units are also used in known vehicle dynamics control systems and are therefore familiar to those skilled in the art. In particular, the brake pressure in the wheel brakes 106VL, 106VR, 106HL, 106HR can be increased by means of the hydraulic unit 105 to carry out an automatic braking process.

In addition to the service brake system, the vehicle 100 can, in one embodiment, have an electric parking brake (EPB), which can be actuated by means of a parking brake actuator 117. The EPB includes, for example, duo-servo or combination caliper wheel brakes, which are locked by the parking brake actuator 117, which, for example, has one or more electric motors or one on the wheel brakes 106HL; 106HR includes hydraulics arranged on the rear wheels 107HL, 107HR. The driver preferably controls the EPB by means of a switch which is arranged within the vehicle 100, with the parking brake actuator 117 locking the EPB based on a signal given by the switch. Furthermore, the parking brake actuator 117 can be controlled electronically independently of the driver.

In addition, the motor vehicle 100 has a driving state sensor system 110. This includes, in particular, wheel speed sensors, from whose signals the driving speed of the motor vehicle 100 can be determined, a yaw rate sensor for determining the yaw rate of the motor vehicle 100 and, if necessary, a lateral acceleration sensor for determining the lateral acceleration of the motor vehicle 100. Preferably the driving state sensor system 110 further includes a steering angle sensor arranged within the steering line 108 for detecting the steering angle of the front wheels 107VL, 107VR. In particular, the current driving dynamic state of the motor vehicle 100 can be determined using the measurement data from the driving state sensor system 110.

To detect surrounding objects 112 in the surroundings of the motor vehicle 100, it also has an environmental sensor system 111. The environmental sensor system 111 includes, for example, a radar sensor with a detection area 113, which corresponds to a solid angle area in front of the motor vehicle 100. Alternatively or in addition to the radar sensor, the environment sensor system 111 can contain, for example, a lidar, infrared or video sensor. Furthermore, the detection area 113 of the surroundings sensor system 111 can also be expanded by means of suitable surroundings sensors in such a way that it additionally includes the side and/or rear surroundings of the motor vehicle 100. The surrounding objects 112 located in the detection area 113 and detected by the surrounding sensor system 110, which are relevant with regard to a possible collision with the motor vehicle 100, are primarily other motor vehicles that move in road traffic together with the motor vehicle 100 . To differentiate linguistically from other motor vehicles, the motor vehicle 100 is therefore also referred to below as the ego vehicle 100.

By means of the surrounding sensor system 111, the relative position and relative speeds of the surrounding objects 112 located in their detection area 113 are determined in relation to the ego vehicle 100. Based on the sensor data, a classification of the detected surrounding objects 112 is also carried out in an evaluation electronics of the surrounding sensor system 111. For example, based on the detected movement of the surrounding objects 112 and based on the detected outlines of the surrounding objects 112, the surrounding objects 112 moving in road traffic are distinguished from those surrounding objects 112 that are located on the edge of the road or next to the road.

If the environment sensor system 111 includes a video sensor, lane markings can also be detected, and the evaluation electronics of the environment sensor system 111 can use their course to determine the course of the road on which the ego vehicle 100 and the surrounding objects 112 participating in road traffic move. If the lane markings cannot be detected using the surrounding sensor system 111 used, the course of the road can be estimated using environmental objects 112 that delimit the road - such as guardrails.

Environment data and driving status data of the ergo vehicle 100 are fed within the ego vehicle 100 to a safety system 114, which uses this data to recognize potentially critical driving situations in which a collision between the ego vehicle 100 and an environmental object 112 can occur. To detect such situations, for example, a risk potential is calculated and compared with a threshold value. The hazard potential is a measure of the probability of a collision between the ego vehicle 100.

In one embodiment, trajectories of the surrounding objects 112 are calculated based on the movement data of the detected surrounding objects 112. Furthermore, a trajectory of the ego vehicle 100 is calculated based on the data recorded by the driving status sensor 110. Using the trajectories, the surrounding objects 112 for which a collision cannot be ruled out are then determined. The time period until a collision (TTC) is determined for these surrounding objects 112. Preferably, a collision avoidance deceleration is also determined which corresponds to the deceleration of the ego vehicle 100 that is required to avoid a collision with the surrounding object 112 through a braking maneuver. In addition, an evasive lateral acceleration can be determined, which corresponds to the lateral acceleration that must be achieved during an evasive maneuver in order to prevent a collision with the surrounding object. Methods for calculating the TTC, the collision avoidance deceleration and the avoidance lateral acceleration that can be used here are, for example, in the international patent application WO 2005/ 082 681 A1 described.

The TTC, the collision avoidance deceleration, and the avoidance lateral acceleration can be used individually or in combination to determine the hazard potential. The danger potential is greater the smaller the TTC is and the greater the collision avoidance deceleration and the avoidance lateral acceleration. Other variables can of course also be used to determine the risk potential. An exemplary method for calculating a hazard potential is also provided in the international patent application WO 2005/ 082 681 A1 described. However, other methods can also be used.

Depending on the risk potential of the detected surrounding objects 112, the security system 114 initiates graduated security measures. At lower levels, the safety measures include, for example, warnings to the driver to make him aware of the dangerous situation so that he can take appropriate measures to avoid a collision. In higher levels, automatic interventions in the driving behavior of the ego vehicle 100 are preferably provided, such as automatic braking maneuvers or automatic evasive maneuvers. In automatic braking maneuvers, target braking can be provided at different intervention levels, which are carried out with a predetermined braking force, as well as full braking, in which the ego vehicle 100 is braked with maximum braking force. In addition, measures to increase the passive safety of the occupants of the ego vehicle 100 can be carried out.

Different threshold values of the risk potential are preferably assigned to the intended levels, so that measures of a specific level are carried out if the risk potential exceeds the corresponding threshold value but remains below the threshold value of the next level.

The warnings may include visual, acoustic and haptic warnings, and are issued by suitable devices of the ego vehicle 100, which are controlled by the security system 114. Visual warnings can be issued by display devices which output visual information in the driver's field of vision. To issue acoustic warnings, loudspeakers are installed in the interior of the ego vehicle 100. A haptic warning is conveyed, for example, via the steering handle 109 by applying a suitable torque to the steering train 108 using the steering actuator 120. This can, for example, be a torque with relatively high-frequency changes in direction, which generates a type of vibration of the steering handle 109. Likewise, it can be provided, for example, to generate vibrations of the foot pedals, in particular the accelerator pedal 102, using suitable actuators.

To carry out automatic braking processes, the hydraulic unit 105 is controlled by the safety system 114. During target braking, the brake pressure in the wheel brakes 106VL, 106VR, 106HL, 106HR is adjusted in such a way that the intended deceleration results. During full braking, the brake pressure in the wheel brakes 106VL, 106VR, 106HL, 106HR is increased to a predetermined maximum value by means of the hydraulic unit 105, so that a maximum deceleration results. Blocking of the wheels 107VL, 107VR, 107HL, 107HR is preferably prevented by a known anti-lock braking system (ABS) during emergency braking.

An automatic evasive maneuver is carried out by controlling the steering actuator 120. Here, the security system 114 can, for example, calculate a path on which the ego vehicle 100 should avoid the relevant surrounding object 112. The steering actuator 120 is then controlled in a suitable manner in accordance with a path following control. As described above, in one embodiment, a specific steering angle on the front wheels 107VL, 107VR can be set using the steering actuator 120, regardless of the driver's specification. In this embodiment, the evasive maneuver can be carried out without driver interaction. In a further embodiment, the steering train 108 can be subjected to a torque by means of the steering actuator 120, which the driver usually counteracts with a counter torque. In this embodiment, the driver is essentially instructed to carry out the evasive maneuver.

Measures to increase the passive safety of vehicle occupants include, for example, tightening seat belts using reversible belt tensioners. In addition, it can be provided to improve the sitting position of one or more vehicle occupants with regard to a collision by controlling motors arranged on the seats. For example, the backrests of front seats can be raised, thereby improving the effectiveness of restraint devices such as airbags or pyrotechnic belt tensioners. Furthermore, it can be provided that open windows and any opened sunroof are automatically closed in order to increase safety. A further measure to increase the passive safety of vehicle occupants is preconditioning of airbags and other restraint devices, in which the triggering mechanism of the restraint device is adjusted in such a way that the restraint device is triggered more quickly in the event of a collision.

A security measure controlled by the security system 114 is terminated when a predetermined termination condition is met. In one embodiment, this can be the case if the risk potential falls below a predetermined threshold value. The threshold value is chosen so that it can be assumed that the present driving situation is so uncritical that the driver can handle it independently. Alternatively or additionally, it can be provided that interventions controlled by the safety system 114, in particular a braking or steering intervention, are ended after a predetermined period of time. This period of time can be, for example, between 0.5 and 5 seconds, preferably 2 seconds. This means that in some cases a driving maneuver is only initiated by the safety system 114, but not ended.

Depending on how critical the driving situation was in which the safety system 114 was active is, and depending on the driver's disposition, the driver is indisposed after the end of the intervention controlled by the safety system 114 or after the end of the critical driving situation and is no longer able to safely drive the ego vehicle 100. Therefore, support for the driver is provided even after the critical driving situations have ended. This happens through further assistance functions of the ego vehicle 100, which are activated by the security system 100. The assistance functions include an ACC function (ACC: Adaptive Cruise Control), a cornering assistant and an AVH function (AVH: Active Vehicle Hold).

To interact with these functions, the security system 114 is as in 1 shown, signally connected to control units 202, 204 and 206 for these assistance functions. The control units 202, 204 and 206 are designed as software modules that are executed by a processor in a control unit of the ego vehicle 100. A single control device can be provided in which the functions are carried out. In addition, the security system 114 can be at least partially implemented as a further software module in the control device. However, it can also be provided that the control units 202, 204 and 206 as well as the security system 114 are implemented in different control devices.

The assistance functions can preferably also be activated by the driver and used as convenience functions independently of the safety system 114. In this case, their activation after completion of the security measures controlled by the security system 114 represents a value-added function that is relatively easy to implement.

The intended procedure is shown in the schematic flow diagram in 2 and is explained below.

The type of support provided depends on whether the vehicle 100 is moving forward or at a standstill when the measures controlled by the safety system 114 are completed. Therefore, after completing the security measures in step 302, the safety system 114 checks in step 304 whether the ego vehicle 100 is moving in a forward direction or whether it is at a standstill. If it is determined that the ego vehicle 100 is moving in a forward direction, the safety system 114 checks in step 306 whether the ACC function is activated. If this is not the case, then the security system 114 activates the ACC function by transmitting a corresponding control command to the ACC control unit 202 in step 308. Alternatively or additionally, the security system 114 checks in step 306 whether the curve assistance function is activated. If this is not the case, the safety system 114 activates the cornering assistance function by transmitting a corresponding command to the control unit 204, which is intended to carry out this function.

In step 306 it could also be determined that the ACC function or the cornering assistance function is already activated if the activation was carried out by the driver himself before the start of the critical driving situations. In this case, the active state of the corresponding function is maintained and the method presented ends in step 310.

The ACC function carried out in the control unit 102 is a distance control that regulates a predetermined distance between the ego vehicle 100 and a vehicle driving ahead in traffic. For this purpose, vehicles in front are detected using the radar sensor included in the surroundings sensor system 112 or another forward-facing surroundings sensor. The measurements result in the distance of a vehicle in front to the ego vehicle 100, which is compared with the desired distance. From the difference between the desired and the actual distance and, if necessary, from the changes in this difference, the control unit 202 determines an acceleration request in order to adjust the speed of the ego vehicle 100 so that the desired distance to the vehicle in front is achieved. An increase in the vehicle speed can be achieved by increasing the drive torque provided by the drive motor 101. For this purpose, the drive motor 101 is suitably controlled by the control unit 202. To reduce the vehicle speed, the drive torque provided by the drive motor 101 can be reduced by suitable control of the drive motor 101. Furthermore, an automatic braking process can be carried out by the control unit 202 by appropriately controlling the hydraulic unit 105 in order to reduce the vehicle speed. The ACC function is known to those skilled in the art and can be carried out in a conventional manner within the scope of the invention. For a description of the ACC function, reference is also made, as an example, to the publication “Adaptive vehicle speed control ACC”, Robert Bosch GmbH (publisher), Yellow Series, 2002 edition.

The distance to the vehicle in front to be set by the ACC function can can be varied continuously or gradually. If the ACC function is activated by the security system 114 as described above, then a maximum distance is preferably set. If a stepwise variation is intended, then the step with the largest distance is preferably selected. In one embodiment, it can also be provided that a distance previously set by the driver or a distance level selected by the driver is overwritten by the control unit 202.

In one embodiment, the control unit 202 can also change a distance previously set by the driver if it was determined in step 306 that the ACC function was already activated. In this case, a command for setting the maximum distance or the highest distance level can be transmitted from the safety system 114 to the control unit 202 in step 310, whereby a different distance specification that may have been set by the driver is overwritten.

The curve assistance function carried out by the control unit 204 reduces the vehicle speed in front of a curve to be driven in such a way that the curve can be driven through safely. In particular, the vehicle speed is reduced to such an extent that understeer or swerving in the curve is avoided. The speed to be set is determined by the control unit 204 depending on the curve radius and compared with the actual vehicle speed, which is determined using the wheel speed sensors. If the actual vehicle speed is greater, then the ego vehicle 100 is braked to the set speed in good time before driving through the curve. This is done by reducing the drive torque provided by the drive motor 101, which is requested by the control unit 204, or by an automatic braking process controlled by the control unit 204, in which the hydraulic unit 105 creates a brake pressure in the wheel brakes 106VL, 106VR, 106HL, 106HR is built. If the actual vehicle speed is lower than the value to be set, then the control unit 204 initially does not intervene in the driving behavior of the ego vehicle 100.

If the driver accelerates the ego vehicle 100 beyond the set speed, the control unit 204 preferably controls the output of a warning. This can be a visual, acoustic and/or haptic warning, as already described above.

In one embodiment, the detection of a curve to be traveled and its radius is carried out using lane detection, which is carried out using the data from the surrounding sensor system 111. For this purpose, as described above, the course of lane markings is evaluated. In addition, stationary objects on the edge of the road can be used to determine the course of the lane.

In an alternative embodiment, the position of the ego vehicle 100 is determined using a positioning system. This can be a satellite positioning system known to those skilled in the art, in particular a GPS system (GPS: Global Positioning System), which can be part of a navigation system present in the ego vehicle 100. The determined position of the ego vehicle 100 is compared with map data that is stored in the ego vehicle 100 and contains route data. A route on which the ego vehicle 100 is located is first determined. Furthermore, the position of the ego vehicle 100 on this route and its direction of travel are determined. The course of the road to be traveled by the ergo vehicle 100 is then determined from this information. In particular, the distance of the ego vehicle 100 from a curve can be determined based on this information from the map data, so that the vehicle 100 can, if necessary, be braked in good time before driving through the curve. In this embodiment, the curve radius is determined from the road course described in the map data. It can also be provided that the curve radii of the curves specified in the map data are already included in the map data. In this case, the curve radius can be read directly from the map data and no calculation is required.

If the security system 114 determines in the previously described step 304 that the ego vehicle 100 is at a standstill after the end of the security measures, then it checks in step 312 whether the AVH function executed by the control unit 206 is activated. This could be the case, for example, if it was switched on by the driver before the critical driving situations began. If it is determined in step 312 that the AVH function is not activated, then the security system 114 activates the AVH function in step 314 by transmitting a corresponding command to the control unit 206. Otherwise, the method ends in step 316.

The AVH function is explained below using the schematic flowchart in 3 explained. In step 402, the AVH control unit 206 initially controls the hydraulic unit 105 in such a way that that a brake pressure is automatically set in the wheel brakes 106VL, 106VR, 106HL, 106HR, which keeps the ego vehicle 100 safely at a standstill. In principle, this brake pressure can be determined in any manner known to those skilled in the art. In one embodiment, the set brake pressure corresponds to the brake pressure that was set during the braking process in order to bring the ego vehicle 100 to a standstill. This brake pressure is locked in the wheel brakes 106VL, 106VR, 106HL, 106HR by closing valves within the hydraulic unit 105. In a further embodiment, it can also be provided, for example, that the control unit 206 calculates the brake pressure to be set from the longitudinal inclination angle of the ego vehicle 100 and an estimated value for its mass in such a way that a braking force is generated which is the downhill force F _slope = which acts on the ego vehicle 100 mg-sin(a) compensated (m: vehicle mass; g: gravitational acceleration; α: longitudinal inclination angle).

The maintenance of the brake pressure in the service brake system of the ego vehicle 100 is preferably limited in time. Therefore, in step 404, the AVH control unit preferably checks whether a predetermined time period T has elapsed since the valves were closed. If this is the case, then in step 406 the AVH control unit 206 preferably closes the electronic parking brake by appropriately controlling the parking brake actuator 117. In addition, in step 406 the brake pressure present in the service brake system is reduced. There is therefore a transition from the service brake system to the electronic parking brake, whereby the vehicle 100 can be kept safely at a standstill permanently.

If the predetermined time period has not yet expired, the AVH control unit 206 checks in step 408 whether the driver's desire to drive away can be recognized. If this is the case, then the brake pressure trapped in the service brake system is reduced in a suitable manner in step 410, in particular in such a way that a jerk-free and roll-back-free start-up is possible. In principle, any criterion known to those skilled in the art can be used to recognize a driver's desire to drive away. An example of a usable criterion is in the German patent application DE 10 2005 011 032 A1 described.

As long as the predetermined time period has not yet expired and the driver's desire to drive away is not determined, the AVH control unit 206 checks in step 412 whether the driver leaves the ego vehicle 100 or the drive motor 101 is switched off. If the driver leaves the ego vehicle 100 or the drive motor 101 is switched off, a transition to step 406 also occurs in which the AVH control unit 206 closes the electronic parking brake and reduces the brake pressure present in the service brake system. This also ensures that the vehicle 100 is safely held at a standstill during a longer standstill period, which can be assumed when the driver leaves the ego vehicle 100 or switches off the drive motor 101. Leaving the ego vehicle 100 can be determined, for example, when a seat occupancy sensor arranged on a driver's seat reports to the AVH control unit 206 that the driver is leaving his position in the driver's seat.

The test steps described above are processed cyclically by the AVH control unit 206 until the method ends in step 406 or 410. The order of the test steps 404, 408 and 412 can deviate from the order described above and can basically be chosen arbitrarily.

Although the invention has been described in detail in the drawings and the preceding representation, the representations are to be understood as illustrative and not restrictive; In particular, the invention is not limited to the exemplary embodiments explained.

Further variants of the invention and its implementation will be apparent to those skilled in the art from the previous disclosure, the figures and the patent claims. Terms such as “comprise,” “comprise,” “include,” “contain,” and the like used in the patent claims do not exclude other elements or steps. The use of the indefinite article does not exclude a plural. A single device can carry out the functions of several units or devices mentioned in the patent claims. A computer program may be provided by a suitable medium, for example an optical or solid-state storage medium, which may also be provided together with or as part of other hardware devices. Likewise, a computer program can also be made available in other ways, such as via the Internet or another communication system. Reference symbols specified in the patent claims are not to be viewed as restrictions on the means and steps used.

Claims (9)

Method for supporting a vehicle operator in driving a vehicle (100), - in which a critical driving situation is recognized using recorded environmental data, whereupon - at least one safety measure with the The aim is to prevent a collision with a detected environmental object (112) and/or to reduce the consequences of a collision with a detected environmental object (112) for the vehicle operator and in which - at least one assistance function (202; 204; 206) is activated, which supports the vehicle operator in guiding the vehicle (100) after the critical driving situation has ended, wherein - the distance control (202) and/or the curve speed control (204) are activated if the vehicle (100) is in motion when the safety measure ends and - the assistance function is a holding function (206) which keeps the vehicle (100) at a standstill by actuating a brake system, the holding function (206) being activated if the vehicle (100) is at a standstill when the security measure is terminated. Procedure according to Claim 1 , wherein the assistance function to be activated is selected depending on a movement state of the vehicle (100) after the safety measure has ended. Procedure according to Claim 1 or 2 , whereby the safety measure is ended when a predetermined period of time has passed since the start of the safety measure or when the risk potential of the driving situation has reduced to a predetermined extent. Method according to one of the preceding claims, wherein the assistance function is a distance control (202) which regulates a distance to a vehicle in front to a predetermined target value by regulating a speed of the vehicle (100). Method according to one of the preceding claims, wherein the assistance function is a curve speed control (204) which determines a curve to be traveled by the vehicle (100) and sets a vehicle speed which is determined as a function of a radius of the curve. Procedure according to Claim 5 , wherein the curve to be traveled is determined in accordance with a position of the vehicle (100) determined by a positioning system using map data, and the curve radius is determined based on the map data. Procedure according to Claim 5 , whereby the curve is determined based on recorded environmental data using lane detection, and the curve radius is determined based on the environmental data. Computer program comprising instructions for executing a method according to one of the preceding claims on a processor. Device for supporting a vehicle operator in driving a vehicle (100), comprising - a safety system that is designed to recognize a critical driving situation using recorded environmental data and to control the execution of at least one safety measure with the aim of preventing a collision with a detected environmental object and / or the consequences of a collision with a detected environmental object for the vehicle operator to reduce and - at least one control unit for executing an assistance function that supports the vehicle operator in driving the vehicle (100), the assistance function being able to be activated by the safety system so that it supports the vehicle operator in driving the vehicle (100) after the critical driving situation has ended , where - the distance control (202) and/or the cornering speed control (204) are activated if the vehicle (100) is in motion when the safety measure is ended, and - the assistance function is a holding function (206) which keeps the vehicle (100) at a standstill by actuating a brake system, the holding function (206) being activated if the vehicle (100) is at a standstill when the safety measure is ended .

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