GB2624101A - 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 submerged in water (3), the vehicle (1) having vehicle components (5) and at least one ultrasound sensor (7) with an acoustically excitable sensor surface (9). The process detecting the vehicle is submerged in water by detecting excitation of the acoustically excitable sensor surface (9) by the water (3) when the vehicle (1) is submerged in the water (3), wherein an electrical signal (11, fig 3) is generated and/or performing an impedance measurement by the at least one ultrasound sensor (7), wherein a current impedance value (13, fig 3) is determined. The method involving evaluation of the electrical signal (11) and/or the current impedance value (13) by comparison to a respective threshold value and activating vehicle components (5) when the respective threshold value is exceeded. The ultrasound sensor preferably being a driving assistance sensor such as a parking sensor and arranged on the bumper or roof of the vehicle. The respective threshold values are preferably a reference electrical signal or impedance value determined when the sensor is surrounded by air.

Description

Method for detectinq an accident and vehicle comprising a detection unit for carrying out the method

Technical field

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

The prior art

Modern vehicles are equipped with a plurality of driving assistance systems that help the driver of the vehicle to perform various manoeuvres. Furthermore, driver assistance systems are known which warn the driver of dangers in the environment or actuate protective mechanisms in the event of an accident. For their function, the driving assistance systems require precise data about the vehicle's environment.

Ultrasound-based object localisation methods are often used. Ultrasound sensors emit ultrasound signals and receive reflected ultrasound echoes from objects in the environment. From the transit time of the ultrasound signals until the reception of the corresponding ultrasound echo as well as the known sound velocity, the distance between a reflecting object and the respective sensor can be determined in each case.

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

In the event of accidents involving bodies of water where the vehicle is submerged in the water, there is a risk that the passengers of the vehicle may drown, especially if they are unable to extricate themselves from the vehicle. Vehicle submersion can occur as a result of an accident, wherein the vehicle leaves the roadway and submerges into a body of water such as a lake or river. Another cause of accidents with risk of drowning can be heavy rain.

The chances of survival in the event of an accident in the water increase if a means of escape from the vehicle is provided. Due to the large forces required by the displacement mechanism, it is difficult to open, especially doors of a vehicle that is in water.

In a water-related accident, the vehicle often hits the water surface hard, depending on the velocity and height of fall and the associated impact angle. As the case may be, the vehicle floats at first. Depending on the course of the accident and any rollover that may have occurred, the roof of the vehicle may be pointed downwards in the process. As soon as water enters the vehicle, it begins to sink. Depending on the position of the motor, tilting of the vehicle may occur. Another movement of the vehicle may be due to current, for example in flowing water.

Known protection systems, such as those intended for automated opening of vehicle openings in an emergency, are tied to airbag control units or radar control units, for example.

Disclosure of the invention

A method for detecting an accident in which a vehicle is at least partially submerged in water is proposed, the vehicle having vehicle components and at least one ultrasound sensor having an acoustically excitable sensor surface, comprising the steps of: a excitation of the acoustically excitable sensor surface by the water when the vehicle is submerged in the water, producing an electrical signal and/or b performing an impedance measurement using the at least one ultrasound sensor, wherein a current impedance value is determined, 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, 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, wherein the detection unit comprises the at least one ultrasound sensor, a memory 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 particular, in the context of the present invention, existing sensors or existing sensor information is used to detect a water accident, taking advantage of the vehicle's contact with the water.

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

The at least one ultrasound 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. On the vehicle shell, the at least one ultrasound sensor is preferably embedded in sheet metal or plastic. If the at least one ultrasound sensor is arranged on the roof of the vehicle, this ultrasound sensor can additionally be used to determine clearance heights, for example during parking operations and/or when using roof-mounted luggage or bicycle carriers.

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

The at least one ultrasound sensor preferably has a horizontal opening angle in a range of 1000 to 1500, for example 1200. A range of the at least one ultrasound sensor is preferably in a range from 1 m to 5 m, more preferably from 2 m to 4 m.

An accident in which a vehicle is at least partially submerged in water often comprises at least one and especially all, of the following phases: - straying phase, wherein the vehicle in particular leaves a lane, i.e., for example, leaves a road, -flight phase, with the vehicle in particular having no contact with the ground until it hits a water surface, - collision phase, with the vehicle hitting the water surface in particular, - submersion phase, in which the vehicle sinks in particular and the vehicle fills with water as the case may be, -sinking phase, wherein the vehicle is partially or completely under water.

Unambiguously interpretable signals based on the physical measurement principle of the at least one ultrasound sensor can be used to detect the accident in the collision phase as well as in the submersion phase and/or the sinking phase.

The way of using the at least one ultrasound sensor for detecting the specific case of water contact of the vehicle is defined in the steps a) and b) according to the invention. In the method, step a) or step b) can be executed. Alternatively, step a) and step b) can be executed. Preferably, step b) and, as the case may be, step a) are executed.

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

The acoustically excitable sensor surface of the at least one ultrasound sensor is excited in particular by the impact of the vehicle on the water surface. In particular, the impact generates an electrical signal from the vibrating acoustically excitable sensor surface, which can be detected. Here, the use of the at least one ultrasound sensor deviates from the typical and operational use of known parking aids, wherein 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 because a stronger electronic signal is generated by direct mechanical excitation of the acoustically excitable sensor surface by the water than by a reflected ultrasound echo. The acoustically excitable sensor surface is excited particularly in the collision phase.

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

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

Alternatively or in addition to the excitation of the acoustically excitable sensor surface by the impact on the water surface, an impedance measurement is performed by means of the at least one ultrasound sensor, wherein a deviation from a usual result of the impedance measurement, which was determined before the accident, is detected.

During and after submersion in water, the at least one ultrasound sensor is, in particular, completely or partially surrounded by water. The at least one ultrasound sensor is surrounded by water, particularly in the submersion phase and/or sinking phase. In contrast to an accident without water reference, for example against a barrier, the sensor can continue to work when surrounded by water. In particular, the electrical system of the at least one ultrasound sensor is subjected to a characteristic change in acoustic impedance that can be measured electrically.

In particular, the impedance measurement is performed in addition to the usual functions of the at least one ultrasound sensor, preferably measuring current and voltage. For example, a frequency of the at least one ultrasound sensor in usual operation with output of an ultrasound signal and reception of the reflected signal is 100 ms or 200 ms. Impedance measurement can be performed in the pauses between the usual ultrasound measurements.

Preferably, the threshold value with respect to the current impedance value is a reference impedance value measured when the at least one ultrasound sensor is surrounded by a gaseous medium, in particular air. If the environment of the at least one ultrasound sensor changes from air to water, the acoustic impedance increases sharply. The acoustic impedance is understood in particular as the radiation resistance. The acoustic impedance describes in particular the relationship between pressure and velocity of particles on the acoustically excitable sensor surface. When the medium is changed from an air environment to a water environment, the acoustic impedance is increased by about three orders of magnitude, which also increases the electrical impedance. The electrical impedance depends on the acoustic impedance of the ultrasound sensor in the environment. Preferably, the current electrical impedance is 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 performed by means of the at least one ultrasound sensor, wherein the reference impedance value is determined as long as the at least one ultrasound sensor is surrounded by air. Furthermore, the reference impedance value can be determined, in particular in advance, on another sensor and/or body, for example on a vehicle pre-series.

In particular, the memory unit can hold the reference impedance value determined in advance.

Preferably, the vehicle components are 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 analysed for evaluation. For example, false triggering due to brief submersion of the vehicle in the terrain, for example when crossing a river, can be avoided.

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

The location data can, for example, come from GPS systems and/or other location services. Location data preferentially comprises data on mapped water bodies. Sensor fusions can also be used for plausibility checks. Preferably, more than one additional sensor is used for plausibility checks. Thus, acceleration and/or angular rate sensors can already provide information in the flight phase and/or in the collision phase. Location data and acceleration sensors can also be used to detect a vehicle drifting away, enabling the vehicle passengers to be rescued more quickly.

In addition, an ultrasound measurement based on the measurement principle of the ultrasound transit time method can be used for plausibility checks, wherein the time interval between the ultrasound pulse and the echo input is measured. For this purpose, the at least one ultrasound sensor is used in particular in the straying phase and/or in the flight phase.

Preferably, the at least one ultrasound sensor and, as the case may be, the additional sensors are evaluated in the straying phase, the flight phase, the collision phase, the submersion phase and/or the sinking phase and, as the case may be, also before that.

Preferably, the vehicle components are activated in the submersion phase and/or the sinking phase. In this way, appropriate automatic relief measures are initiated.

Activating vehicle components preferably comprises actuating an alarm and/or unlocking and, as the case may be, opening a restraint system, window, door, tailgate and/or sunroof of the vehicle. The restraint system is, for example, a belt system. Accordingly, the vehicle components are preferably selected from alarm transmitters, restraint systems, in particular seat belt systems, windows, doors, tailgate, sunroof and/or protective mechanisms that affect energy storage systems of the vehicle. The protective mechanisms that affect energy storage devices of the vehicle 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 the 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 transmitter, which is understood to mean an automatic emergency call system that uses mobile radio and satellite positioning to automatically or manually establish a telephone connection to an emergency centre after an accident. In addition to the voice connection, an eCall system installed in the vehicle can transmit information about the accident location, the type of triggering and/or the vehicle. In the case of an xCall, in particular, a message is sent to one or more defined recipients, for example, to all cell phones and/or vehicles with cellular connectivity in the vicinity.

When the vehicle components are activated, the vehicle passengers should check whether other vehicle passengers require assistance and leave the vehicle through the openings provided, especially before or during the submersion phase or the sinking phase. The activation of the vehicle components preferably takes place before or during the submersion phase and/or the sinking phase. The selection of the vehicle components to be activated as well as the type and sequence of actions is preferably defined in a program, which is further preferably stored in the memory unit. Furthermore, the vehicle sensors can be used to determine which parts of the vehicle are in the water so that the activation can be adjusted accordingly.

The vehicle preferably has at least partially waterproof electronic components, wherein the functionality of at least one of the vehicle components is maintained for at least 5 minutes, more preferably at least 10 minutes and for example up to 20 minutes after submersion. This makes it possible, for example, to also use power windows to open the window. The waterproof electronic components preferably feature waterproof housing technology and/or waterproof interconnect technology. As the case may be, sealed printed circuit boards can be present, which are produced in particular by submersion in lacquer.

In addition, it can be detected whether there are passengers in the vehicle at the time of the accident. If the vehicle is free of vehicle passengers, the activation of the vehicle components can be exclusively the actuation of an alarm, wherein unlocking and, as the case may be, opening of vehicle components is prevented in order to make it more difficult for unauthorised persons to access the vehicle, as the case may be.

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

Advantages of the invention The method proposed according to the invention for detecting an accident in which a vehicle is at least partially submerged in water, or by the vehicle according to the invention, makes it possible to double the function of already existing ultrasound sensors, combining convenience functions, such as parking aids and safety functions.

Ultrasound sensors are very common and robust, and thus can be used to prevent drowning deaths in the event of water-related accidents.

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

Robust detection of the hazardous situation can take place and safety systems can be triggered. Plausibility checks reduce the false positives 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.

The following is shown: Figure 1 a first exemplary sequence of an accident, Figure 2 a second exemplary sequence of an accident and Figure 3 a schematic representation of an embodiment of the method according to the invention.

Embodiments of the invention In the following description of embodiments of the invention, the same or similar elements are designated by the same reference signs, and a repeated description of these elements in individual cases is omitted. The figures represent the object of the invention only schematically.

Figure 1 shows a first exemplary sequence of an accident in which a vehicle 1 is at least partially submerged in water 3. Here, the vehicle 1 approaches the water 3 in forward motion and is submerged in it in the forward direction. The vehicle 1 has vehicle components 5, in this case a window and a roof 17, as well as a bumper 15 on which an ultrasound sensor 7 with an acoustically excitable sensor surface 9 is arranged.

Figure 1 shows a first situation 31, a second situation 33 and a third situation 35 illustrating the sequence of the accident. The first situation 31 corresponds to the straying phase and the flight phase, with the vehicle 1 leaving a roadway and approaching the water 3. In this regard, the ultrasound sensor 7 may detect an ultrasound signal reflected from a water surface 37.

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

The third situation 35 corresponds to the submersion phase and the sinking phase, wherein the vehicle 1 initially floats on the water 3 while being partially submerged and then sinks. The ultrasound sensor 7 is located below the water surface 37 in the water 3. The ultrasound sensor 7 is now surrounded by water 3, so an impedance measurement will determine an actual impedance value 13 that is significantly higher than a reference impedance value measured when the ultrasound sensor 7 was surrounded by air 19.

Figure 2 shows a second exemplary sequence of an accident wherein a vehicle 1 is submerged in water 3. In the variant shown here, the vehicle 1 is submerged in reverse and the ultrasound sensor 7 is arranged on a bumper 15 at the rear of the vehicle 1. Situations 31, 33 and 35 correspond to those shown in Figure Figure 3 schematically shows an embodiment of the method according to the invention. Ultrasound sensors 7 of a vehicle 1 provide an electrical signal 11 by mechanical excitation of the acoustically excitable sensor surface 9 with water 3 and/or a current impedance value 13 by impedance measurement.

Additionally, a reflected ultrasound signal 39 may be provided.

Signals from ultrasound sensors 7 are evaluated in a control unit 24. In a memory 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 for this purpose. The evaluated signals are subjected to a plausibility check 21, which can take into account data from an airbag system 27 and an ADAS system 29.

If the electrical signal 11 and/or the current impedance value 13 exceeds a respective threshold value, vehicle components 5 are activated, provided that plausibility check 21 does not contradict this. Only one vehicle component 5 or also several vehicle components 5 can be activated, wherein in particular an alarm is actuated and windows and doors of the vehicle 1 are at least unlocked and, as the case may be, opened.

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

The invention is not limited to the exemplary embodiments described herein and the aspects highlighted therein. Rather, within the range indicated by the claims, a plurality of variations are possible which are within the scope of skilled practice.

Claims (4)

1. Claims Method for detecting an accident in which a vehicle (1) is at least partially submerged in water (3), the vehicle (1) having vehicle components (5) and at least one ultrasound sensor (7) with an acoustically excitable sensor surface (9), corn prising the following steps: a. excitation of the acoustically excitable sensor surface (9) by the water (3) when the vehicle (1) is submerged in the water (3), wherein an electrical signal (11) is generated and/or b. performing an impedance measurement by the at least one ultrasound sensor (7), wherein 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 to 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.
2. 2. Method according to claim 1, characterised in that the at least one ultrasound sensor (7) is additionally used for functions of a driving assistance system, in particular a parking assistance system.
3. 3. Method according to one of the preceding claims, characterised in that the at least one ultrasound sensor (7) is arranged on a bumper (15) and/or on a roof (17) of the vehicle (1).
4. 4. Method according to one of the preceding claims, characterised in that the activation of vehicle components (5) comprises the actuation of an alarm and/or the unlocking and, as the case may be, opening of a restraint system, a door, a window, a tailgate and/or a sliding roof.Method according to any one of the preceding claims, characterised in that the vehicle (1) comprises at least partially waterproof electronic 7. 8. 9. 10.components, wherein the functionality of at least one of the vehicle components (5) is maintained for at least 5 minutes after submersion.Method according to any one of the preceding claims, characterised in that the threshold value with respect to the current impedance value (13) is a reference impedance value measured when the at least one ultrasound sensor (7) is surrounded by a gaseous medium, in particular air (19).Method according to claim 6, characterised in that the vehicle components (5) are activated if 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 any one of the preceding claims, characterised in that the threshold value with respect to the electrical signal (11) is a reference electrical signal generated by a signal emitted and reflected by the at least one ultrasound sensor (7).Method according to any one of the preceding claims, characterised in that prior to the activation in step d) a plausibility check (21) of the evaluation is performed, wherein additional sensors, such as video, radar, lidar, wheel speed, acceleration and/or rotation sensors and/or location data are used.A vehicle (1) comprising a detection unit for carrying out the method according to any one of the preceding claims, wherein the detection unit comprises the at least one ultrasound sensor (7), a memory 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.