DE102022210003A1 - Method for detecting an accident and vehicle comprising a detection unit for carrying out the method - Google Patents

Abstract

The invention relates to a method for detecting an accident, in which a vehicle (1) is at least partially immersed in water (3), the vehicle (1) having vehicle components (5) and at least one ultrasonic sensor (7) with an acoustically excitable sensor surface (9 ), comprising the following steps:a. Exciting the acoustically excitable sensor surface (9) by the water (3) when the vehicle (1) is immersed in the water (3), an electrical signal (11) being generated and/or b. Carrying out an impedance measurement using the at least one ultrasonic sensor (7), whereby a current impedance value (13) is determined,c. Evaluating the electrical signal (11) and/or the current impedance value (13), wherein the electrical signal (11) and/or the current impedance value (13) is compared with a respective threshold value, i.e. Activating vehicle components (5) when the electrical signal (11) and/or the current impedance value (13) is greater than the respective threshold value. The invention further relates to a vehicle.

Description

Technical area

The invention relates to a method for detecting an accident in which a vehicle is at least partially submerged in water, wherein the vehicle has vehicle components and at least one ultrasonic sensor with an acoustically excitable sensor surface. Furthermore, the invention relates to a vehicle comprising a detection unit.

State of the art

Modern vehicles are equipped with a variety of driving assistance systems that support the vehicle driver in carrying out various maneuvers. Furthermore, driving assistance systems are known which warn the driver of dangers in the environment or trigger protective mechanisms in the event of an accident. In order to function, driving assistance systems require precise data about the vehicle's surroundings.

Ultrasound-based object localization methods are often used. Ultrasonic sensors send out ultrasonic signals and receive ultrasonic echoes reflected from objects in the environment. The distance between a reflecting object and the respective sensor can be determined from the transit time of the ultrasonic signals until the corresponding ultrasonic echo is received and the known speed of sound.

In addition, ultrasonic sensors can also be used for safety-relevant aspects, such as detecting vehicle flooding. Such an application is, for example, in the DE 10 2019 211 188 A1 described. According to the prior art, ultrasonic sensors can be used to detect that a water surface is moving towards the sensor.

In accidents involving water where the vehicle is submerged in water, there is a risk that the occupants of the vehicle will drown, especially if they cannot be extricated from the vehicle. Vehicle submersion can occur as a result of an accident where the vehicle leaves the roadway and enters a body of water such as a lake or river. Another cause of drowning accidents can be heavy rain.

The chances of survival in the event of an accident in the water increase if an escape route from the vehicle is created. Due to the large forces required by the displacement mechanism, opening the doors of a vehicle in the water is difficult.

In a water-related accident, the vehicle often hits the water surface hard, depending on the speed and the height of the fall and the associated impact angle. If necessary, the vehicle initially floats. Depending on the circumstances of the accident and the rollover that may have occurred, the roof of the vehicle may be directed downwards. As soon as water enters the vehicle, it begins to sink. Depending on the position of the engine, the vehicle may tilt. Further movement of the vehicle can occur due to currents, for example in flowing water.

Known protection systems, which are intended for the automated opening of vehicle openings in an emergency, are tied to airbag control devices or radar control devices, for example.

Disclosure of the invention

1. a. Anregen der akustisch anregbaren Sensoroberfläche durch das Wasser beim Eintauchen des Fahrzeugs in das Wasser, wobei ein elektrisches Signal erzeugt wird und/oder
2. b. Durchführen einer Impedanzmessung mittels des mindestens einen Ultraschallsensors, wobei ein aktueller Impedanzwert ermittelt wird,
3. c. Auswerten des elektrischen Signals und/oder des aktuellen Impedanzwerts, wobei das elektrische Signal und/oder der aktuelle Impedanzwert mit einem jeweiligen Schwellenwert verglichen wird,
4. d. Aktivieren von Fahrzeugkomponenten, wenn das elektrische Signal und/oder der aktuelle Impedanzwert größer als der jeweilige Schwellenwert ist.

A method for detecting an accident in which a vehicle is at least partially immersed in water is proposed, wherein the vehicle has vehicle components and at least one ultrasonic sensor with an acoustically excitable sensor surface, comprising the following steps:

1. a. Exciting the acoustically excitable sensor surface through the water when the vehicle is immersed in the water, whereby an electrical signal is generated and/or
2. b. Carrying out an impedance measurement using the at least one ultrasonic sensor, whereby a current impedance value is determined,
3. c. Evaluating the electrical signal and/or the current impedance value, wherein the electrical signal and/or the current impedance value is compared with a respective threshold value,
4. d. Activating vehicle components when the electrical signal and/or the current impedance value is greater than the respective threshold value.

Furthermore, a vehicle is proposed, comprising a detection unit for carrying out the method according to the invention, the detection unit having at least one ultrasonic sensor, a storage unit for storing the respective threshold values and a computing unit for comparing the electrical signal and / or the determined impedance value with the respective threshold value.

In the context of the present invention, existing sensors or existing sensor information are used in particular to detect a water accident, taking advantage of the vehicle's contact with the water.

Preferably, the at least one ultrasonic sensor is additionally used for functions of a driving assistance system, in particular a parking aid, wherein the at least one ultrasonic sensor is preferably used to determine a distance between an object and the vehicle. The use of the at least one ultrasonic sensor for the functions of the driving assistance system precedes in particular the use of the at least one ultrasonic sensor for detecting the accident.

The at least one ultrasonic sensor is preferably arranged on the front, rear and/or side vehicle shell, in particular on a bumper, and/or on a roof of the vehicle. The at least one ultrasonic sensor is preferably embedded in sheet metal or plastic on the vehicle shell. If the at least one ultrasonic sensor is arranged on the roof of the vehicle, this ultrasonic sensor can also be used to determine headroom, for example when parking and / or when using roof luggage or bicycle racks.

The at least one ultrasonic sensor can be arranged at the front, rear and/or side of the vehicle. Further preferably, the vehicle comprises up to six ultrasonic sensors, which are used in particular in the method according to the invention.

The at least one ultrasonic sensor preferably has a horizontal opening angle in a range of 100° to 150°, for example 120°. A range of the at least one ultrasonic sensor is preferably in a range from 1 m to 5 m, more preferably from 2 m to 4 m.

• - Abkommensphase, wobei das Fahrzeug insbesondere eine Fahrbahn verlässt, also zum Beispiel von einer Straße abkommt,
• - Flugphase, wobei das Fahrzeug insbesondere keinen Kontakt zum Boden aufweist, solange bis es auf eine Wasseroberfläche auftrifft,
• - Kollisionsphase, wobei das Fahrzeug insbesondere auf die Wasseroberfläche auftrifft,
• - Tauchphase, wobei das Fahrzeug insbesondere untergeht und sich das Fahrzeug gegebenenfalls mit Wasser füllt,
• - Sinkphase, wobei sich das Fahrzeug teilweise oder vollständig unter Wasser befindet.

An accident in which a vehicle is at least partially submerged in water often includes at least one, and in particular all, of the following phases:

• - Agreement phase, whereby the vehicle in particular leaves a lane, for example coming off a road,
• - Flight phase, in which the vehicle in particular has no contact with the ground until it hits a water surface,
• - Collision phase, in which the vehicle particularly hits the water surface,
• - Diving phase, in which the vehicle sinks and the vehicle possibly fills with water,
• - Sinking phase, where the vehicle is partially or completely submerged.

To detect the accident, clearly interpretable signals based on the physical measurement principle of the at least one ultrasonic sensor can be used in the collision phase as well as in the diving phase and/or the sinking phase.

The type of use of the at least one ultrasonic sensor for detecting the specific case of water contact of the vehicle is defined in steps a) and b) according to the invention. In the method, step a) or step b) can be carried out. Alternatively, step a) and step b) can be carried out. Step b) and, if necessary, step a) are preferably carried out.

In method step a), in particular an electromagnetic arrangement of an ultrasonic sensor, which is common for parking aids for example, is used, which is mechanically excited so that a sharper and stronger signal is generated. According to method step b), the detection is based on the, in particular electrical, input resistance. The electrical input resistance changes and increases with the changing environment from air to water due to the change in the physical boundary conditions, in particular by a factor of approximately 1500 in the acoustic or mechanical resistance.

The acoustically excitable sensor surface of the at least one ultrasonic sensor is excited in particular by the impact of the vehicle on the water surface. The impact generates in particular an electrical signal from the vibrating acoustically excitable sensor surface, which can be detected. In this case, the use of the at least one ultrasonic sensor differs from the typical and operational use of known parking aids, whereby a reflective signal is usually evaluated. In method step a) according to the invention, in particular the acoustically excitable sensor surface itself is excited by the impact on the water. The resulting signal differs from the usual signals, since a stronger electronic signal is generated by direct mechanical excitation of the acoustically excitable sensor surface through the water rather than through a reflected ultrasonic echo. The acoustically excitable sensor surface is particularly excited in the collision phase.

The acoustically excitable sensor surface is in particular a membrane or a piezo element. The piezo element has in particular ceramic layers.

Preferably, the threshold value with respect to the electrical signal is an electrical reference signal which is generated by a signal emitted and reflected by the at least one ultrasonic sensor. By comparing these signals, the normal application in the context of a parking aid, for example, is differentiated from the accident situation with contact with water.

Alternatively or in addition to stimulating the acoustically excitable sensor surface by the impact on the water surface, an impedance measurement is carried out using the at least one ultrasonic sensor, with a deviation from a usual result of the impedance measurement, which was determined before the accident, being detected.

During and after immersion in the water, the at least one ultrasonic sensor is completely or partially surrounded, in particular, by water. The at least one ultrasonic sensor is surrounded by water, particularly in the diving phase and/or sinking phase. Unlike an accident not related to water, such as hitting a barrier, the sensor can continue to work when surrounded by water. The electrical system of the at least one ultrasonic sensor is in particular exposed to a characteristic change in the acoustic impedance, which can be measured electrically.

The impedance measurement is carried out in particular in addition to the usual functions of the at least one ultrasonic sensor, whereby current and voltage are preferably measured. A frequency of the at least one ultrasonic sensor in normal operation with output of an ultrasonic signal and reception of the reflected signal is, for example, 100 ms or 200 ms. The impedance measurement can be carried out in the breaks between the usual ultrasonic measurements.

Preferably, the threshold value with respect to the current impedance value is a reference impedance value that was measured when the at least one ultrasonic sensor is surrounded by a gaseous medium, in particular air. If the environment of the at least one ultrasonic sensor changes from air to water, the acoustic impedance increases sharply. Acoustic impedance refers in particular to radiation resistance. The acoustic impedance describes in particular the relationship between pressure and speed of particles on the acoustically excitable sensor surface. When changing the medium from an air environment to a water environment, the acoustic impedance is increased by approximately three orders of magnitude, which also increases the electrical impedance. The electrical impedance depends on the acoustic impedance of the ultrasonic sensor in the environment. The current electrical impedance is preferably compared with the respective threshold value. In particular, the change in acoustic impedance during the transition from air to water is detected by an electrical measurement that provides the electrical impedance.

In particular, an impedance measurement is repeatedly carried out using the at least one ultrasonic sensor, with the reference impedance value being determined as long as the at least one ultrasonic sensor is surrounded by air. Furthermore, the reference impedance value can be determined, in particular in advance, on another sensor and/or structure, for example on a pre-series vehicle. In particular, the storage unit can store the previously determined reference impedance value.

The vehicle components are preferably activated when the current impedance value and the reference impedance value differ by a factor of at least 2, in particular at least 10. Furthermore, a series of consecutive impedance measurements can be analyzed for evaluation. For example, false activation can be avoided if the vehicle is immersed briefly in the terrain, for example when crossing rivers.

Preferably, before activating the vehicle components in step d), a plausibility check of the evaluation of step c) is carried out. In particular, additional sensors such as video, radar, LiDAR, wheel speed, acceleration and/or yaw rate sensors and/or location data are used for plausibility checks.

The location data can come, for example, from GPS systems and/or other location services. The location data preferably includes data on mapped waters. Sensor fusions can also be used to check plausibility. More than one additional sensor is preferably used for plausibility checks. Acceleration and/or yaw rate sensors can already provide information in the flight phase and/or in the collision phase. This can be done with location or location data and acceleration sensors In addition, drifting of the vehicle can be detected in order to enable the vehicle occupants to be rescued more quickly.

In addition, to check the plausibility, an ultrasound measurement can be used according to the measuring principle of the ultrasound transit time method, whereby the time period between the ultrasound pulse and the echo input is measured. For this purpose, the at least one ultrasonic sensor is used in particular in the agreement phase and/or in the flight phase.

Preferably, the at least one ultrasonic sensor and, if applicable, the additional sensors are evaluated in the departure phase, the flight phase, the collision phase, the diving phase and/or the descent phase and, if applicable, also before.

The vehicle components are preferably activated in the diving phase and/or the sinking phase. In this way, appropriate automatic assistance measures are initiated.

Activating vehicle components preferably includes triggering an alarm and/or unlocking and, if necessary, opening a restraint system, a window, a door, a tailgate and/or a sunroof of the vehicle. The restraint system is, for example, a belt system. The vehicle components are accordingly preferably selected from alarm devices, restraint systems, in particular belt systems, windows, doors, tailgate, sunroof and / or protective mechanisms that relate to the vehicle's energy storage. The protective mechanisms that affect the vehicle's energy storage are, for example, shutdown devices, in particular valves in lines and/or power electronics, preferably for managing high voltages. The protective mechanisms reduce the risk to passengers, the environment and/or the vehicle. The alarm devices are, for example, horns and/or signal horns. The alarm can be an audible and/or visual alarm or an eCall or an xCall. An eCall is sent in particular by an eCall system as an alarm, which is an automatic emergency call system that uses mobile communications and satellite tracking to automatically or manually establish a telephone connection to an emergency center after an accident. In addition to the voice connection, an eCall system installed in the vehicle can transmit information about the location of the accident, the type of activation and/or the vehicle. With an xCall, in particular, a message is sent to one or more defined recipients, for example to all cell phones and/or vehicles with a cell phone connection in the area.

When activating the vehicle components, the vehicle occupants should check whether other vehicle occupants require assistance and leave the vehicle through the openings provided, in particular before or during the diving phase or the sinking phase. The vehicle components are preferably activated before or during the diving phase and/or the sinking phase. The selection of the vehicle components to be activated and the type and sequence of measures are preferably defined in a program that is more preferably stored in the memory unit. Furthermore, the vehicle sensors can determine which parts of the vehicle are in the water so that the activation can be coordinated accordingly.

The vehicle preferably has at least partially waterproof electronic components, with the functionality of at least one of the vehicle components being maintained for at least 5 minutes, more preferably at least 10 minutes and, for example, up to 20 minutes after immersion. This makes it possible, for example, to use electric window regulators to open the window. The waterproof electronic components preferably have a waterproof housing technology and/or a waterproof connection technology. If necessary, sealed circuit boards can be present, which are produced in particular by immersing them in paint.

In addition, it can be detected whether there are any passengers in the vehicle at the time of the accident. If the vehicle is free of passengers, the activation of the vehicle components can only trigger an alarm, whereby unlocking and possibly opening of vehicle components is prevented in order to make it more difficult for unauthorized persons to access the vehicle.

In addition, the evaluation in step c) can be coupled to other vehicle systems, such as airbag and/or ADAS (Advanced Driver Assistance System) systems.

Advantages of the invention

Through the method proposed according to the invention for detecting an accident in which a vehicle is at least partially submerged in water, or through the vehicle according to the invention, a dual function of already existing ultrasonic sensors is possible, with comfort functions, such as parking aids, and safety functions being combined.

Ultrasonic sensors are very common and robust and can therefore be used to prevent Drowning death can be used in the case of water-related accidents.

The detection of the impact of the acoustically excitable sensor surface on the water surface and the change in the acoustic impedance can be measured electrically and differ greatly from the reference values of the sensors under conditions of normal use of the vehicle. The impedance measurement can be carried out repeatedly and can thus be reliably interpreted as a time series.

Robust detection of the dangerous situation can occur and safety systems can be controlled. The plausibility check reduces the false positive determination of an accident situation.

Brief description of the drawings

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

• 1 einen ersten beispielhaften Ablauf eines Unfalls,
• 2 einen zweiten beispielhaften Ablauf eines Unfalls und
• 3 eine schematische Darstellung einer Ausführungsform des erfindungsgemäßen Verfahrens.

Show it:

• 1 a first exemplary sequence of an accident,
• 2 a second exemplary sequence of an accident and
• 3 a schematic representation of an embodiment of the method according to the invention.

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are referred to with the same reference numerals, with a repeated description of these elements being omitted in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a first example of an accident in which a vehicle 1 is at least partially submerged in water 3. Here, the vehicle 1 approaches the water 3 while driving forward and submerges forward into it. The vehicle 1 has vehicle components 5, here a window, and a roof 17 as well as a bumper 15 on which an ultrasonic sensor 7 with an acoustically excitable sensor surface 9 is arranged.

1 shows a first situation 31, a second situation 33 and a third situation 35, which illustrate the course of the accident. The first situation 31 corresponds to the agreement phase and the flight phase, with the vehicle 1 coming off a road and approaching the water 3. The ultrasonic sensor 7 can detect an ultrasonic signal that is reflected from a water surface 37.

The second situation 33 corresponds to the collision phase in which the vehicle 1 impacts the water surface 37. As a result of the impact, the acoustically excitable sensor surface 9 of the ultrasonic sensor 7 is mechanically excited by the water 3, so that an electrical signal 11 is generated.

The third situation 35 corresponds to the diving phase and the sinking phase, with the vehicle 1 initially floating on the water 3 and being partially submerged and then sinking. The ultrasonic sensor 7 is located below the water surface 37 in the water 3. The ultrasonic sensor 7 is now surrounded by water 3, so that an impedance measurement determines a current impedance value 13 which is significantly above a reference impedance value that was measured when the ultrasonic sensor 7 was surrounded by air 19.

2 shows a second exemplary sequence of an accident, with a vehicle 1 immersed in water 3. In the variant shown here, the vehicle 1 goes into reverse and the ultrasonic sensor 7 is arranged on a bumper 15 at the rear of the vehicle 1. Situations 31, 33 and 35 correspond to those in accordance with 1 .

3 shows schematically an embodiment of the method according to the invention. Ultrasonic sensors 7 of a vehicle 1 deliver an electrical signal 11 by mechanically stimulating the acoustically stimulable sensor surface 9 with water 3 and/or a current impedance value 13 by impedance measurement. In addition, a reflected ultrasound signal 39 can be made available.

Signals from ultrasonic sensors 7 are evaluated in a control device 24. In a storage unit 23 and a computing unit 25, the electrical signal 11 and/or the current impedance value 13 are evaluated and compared with a respective threshold value. The evaluated signals are subjected to a plausibility check 21, which can take data from an airbag system 27 and an ADAS system 29 into account.

If the electrical signal 11 and/or the current impedance value 13 exceeds a respective threshold value, vehicle components 5 are activated, provided that the plausibility check 21 does not conflict with this. Only one vehicle component 5 or several vehicle components 5 can be activated, in particular an alarm being triggered and windows and Doors of the vehicle 1 are at least unlocked and opened if necessary.

It is also possible that, in addition to raw signals that provide a reflected ultrasound signal 39, current and voltage values are transmitted, from which the electrical signal 11, which can also be referred to as an electrical peak, and the current impedance value 13 can be extracted . The corresponding calculation takes place in particular in the control unit 24. The storage unit 23 and the computing unit 25 can be part of the control device 24 or provided separately.

The invention is not limited to the exemplary embodiments described here and the aspects highlighted therein. Rather, within the range specified by the claims, a large number of modifications are possible, which are within the scope of professional action.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed 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.

Cited patent literature

• DE 102019211188 A1 [0004]

Claims (10)

Method for detecting an accident in which a vehicle (1) is at least partially immersed in water (3), the vehicle (1) having vehicle components (5) and at least one ultrasonic sensor (7) with an acoustically excitable sensor surface (9). the following steps: a. Exciting the acoustically excitable sensor surface (9) by the water (3) when the vehicle (1) is immersed in the water (3), an electrical signal (11) being generated and/or b. Carrying out an impedance measurement using the at least one ultrasonic sensor (7), whereby a current impedance value (13) is determined, c. Evaluating the electrical signal (11) and/or the current impedance value (13), wherein the electrical signal (11) and/or the current impedance value (13) is compared with a respective threshold value, d. Activating vehicle components (5) when the electrical signal (11) and/or the current impedance value (13) is greater than the respective threshold value. Procedure according to Claim 1 , characterized in that the at least one ultrasonic sensor (7) is additionally used for functions of a driving assistance system, in particular a parking aid. Method according to one of the preceding claims, characterized in that the at least one ultrasonic sensor (7) is arranged on a bumper (15) and/or on a roof (17) of the vehicle (1). Method according to one of the preceding claims, characterized in that activating vehicle components (5) includes triggering an alarm and/or unlocking and optionally opening a restraint system, a door, a window, a tailgate and/or a sunroof. Method according to one of the preceding claims, characterized in that the vehicle (1) has at least partially waterproof electronic components, the functionality of at least one of the vehicle components (5) being maintained for at least 5 minutes after immersion. Method according to one of the preceding claims, characterized in that the threshold value with respect to the current impedance value (13) is a reference impedance value which is measured when the at least one ultrasonic sensor (7) is surrounded by a gaseous medium, in particular air (19). Procedure according to Claim 6 , characterized in that the vehicle components (5) are activated when the current impedance value (13) and the reference impedance value differ by a factor of at least 2, in particular at least 10. Method according to one of the preceding claims, characterized in that the threshold value with respect to the electrical signal (11) is an electrical reference signal which is generated by a signal emitted and reflected by the at least one ultrasonic sensor (7). Method according to one of the preceding claims, characterized in that before activation in step d), a plausibility check (21) of the evaluation is carried out, with additional sensors such as video, radar, lidar, wheel speed, acceleration and/or Rotation rate sensors and/or location data can be used. Vehicle (1) comprising a detection unit for carrying out the method according to one of the preceding claims, wherein the detection unit has the at least one ultrasonic sensor (7), a storage unit (23) for storing the respective threshold values and a computing unit (25) for comparing the electrical signal ( 11) and/or the determined impedance value (13) with the respective threshold value.

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