Method and device for controlling an occupant restraint device of a vehicle

Abstract

The invention provides a method (100) for controlling an occupant restraint device of a vehicle (1) in a pre-crash phase, wherein a virtual crumple zone (2-5) is defined based on a detection range of an environmental sensor system of the vehicle (1), wherein the virtual crumple zone (2-5) is divided into a plurality of radial sectors (2a-2n, 3a-3n, 4a-4n, 5a-5n) which have a respective predetermined distance (xa-xn) from the vehicle (1), wherein for each sector (2a-2n, 3a-3n, 4a-4n, 5a-5n) a respective relative speed limit value is predetermined based on its respective distance (xa-xn) and a predetermined activation time of the occupant restraint device and is assigned to the corresponding sector (2a-2n, 3a-3n, 4a-4n, 5a-5n), and wherein the method (100) includes in particular the following steps: - determining (103) a current relative speed between the vehicle (1) and the collision object (7) for a current sector (2a-2n, 3a-3n, 4a-4n, 5a-5n) in which the collision object (7) is currently located, - performing (104) a comparison of the determined current relative speed with a relative speed limit value assigned to the current sector (2a-2n, 3a-3n, 4a-4n, 5a-5n), and - controlling (105) the occupant restraint device in dependence on the comparison.

Description

[0001] The invention relates to a method for controlling an occupant restraint system of a vehicle in a pre-crash phase during an impending collision of the vehicle with a collision object based on measurement data from an environmental sensor system of the vehicle. The invention further relates to a device for controlling an occupant restraint system of a vehicle during an impending collision of the vehicle with a collision object, comprising an electronic control unit configured to implement such a method.

[0002] For many years, occupant protection devices, particularly occupant restraint devices, have been known in vehicles. These are designed to protect the occupants of a vehicle in the event of an accident, in particular a collision between the vehicle and a collision or impact object, with the aim of preventing injuries to the vehicle occupants as far as possible or at least reducing their severity. As a rule, such an occupant restraint device in a vehicle comprises one or more restraint devices in the form of airbags, which catch the occupant in the event of a collision. Such an airbag is usually deployed by an inflowing gas in a short time range of between 10 ms and 50 ms between an occupant and parts of the vehicle interior and forms a cushion that protects the occupant from impact with hard parts of the vehicle interior, such as a steering wheel or a side window.Another occupant restraint device of a vehicle is a seat belt with a seat belt pretensioner.

[0003] More modern vehicles, especially semi-autonomous or autonomous vehicles, also typically feature environmental sensor technology, which includes one or more environmental sensors for monitoring a specific area around the vehicle and detecting objects in that area. Such an environmental sensor can be embodied, for example, as a radar sensor, a lidar sensor, or a camera. It is known to use environmental sensor technology as part of a collision or early impact detection system, a so-called pre-crash system, to improve occupant safety.On the basis of signals or measurement data from the environmental sensors, a point in time is estimated at which a collision or impact is unavoidable, this point in time being before the actual collision time, and based on this, in particular before the actual collision, a preconditioning of an occupant restraint device or a control of an occupant restraint device, in particular a reversible one, for example a reversible seat belt tensioner, takes place.

[0004] In particular, the activation of the occupant restraint system depends on the specific collision scenario and, in particular, on the degree of safety and reliability in detecting or determining the presence of an impending, i.e., unavoidable collision. Especially in connection with the activation of an irreversible occupant restraint system, in particular an airbag or an irreversible seatbelt pretensioner, there is a need for a sufficiently high level of safety and reliability to activate such an irreversible occupant restraint system already in the pre-crash phase in order to ensure the greatest possible protection for the occupant.

[0005] Against this background, it is the object of the present invention to provide a method and a device for controlling an occupant restraint device of a vehicle in a pre-crash phase in the event of an impending collision of the vehicle with a collision object, which safely and reliably detect an unavoidable collision and thus enable reliable and needs-based early control and triggering of the, in particular irreversible, occupant restraint device before the actual collision and thus optimal protection of an occupant.

[0006] The above object is achieved by the entire teaching of claim 1 and the independent claim 11. Advantageous embodiments and further developments of the invention are set forth in the subclaims and the following description.

[0007] The method according to the invention for controlling an occupant restraint device of a vehicle in a pre-crash phase in the event of an impending collision of the vehicle with a collision object based on measurement data from an environmental sensor system of the vehicle, wherein, based on a detection range of the environmental sensor system, a virtual crumple zone is defined in an environment of the vehicle and adjacent to the vehicle, wherein the virtual crumple zone is divided into several radial sectors, each of which has a predetermined distance from the vehicle, and wherein, for each sector, a respective relative speed limit value is predetermined and assigned to the corresponding sector based on its respective distance and a predetermined activation time of the occupant restraint device, comprises the following steps: - Detection of the collision object in the virtual crumple zone, - Determining a current relative speed between the vehicle and the collision object for a current sector in which the collision object is currently located, - performing a comparison of the determined current relative speed with a relative speed limit value assigned to the current sector, and - Control of the occupant restraint system depending on the comparison.

[0008] A basic idea of ​​the invention is therefore based on defining a virtual crumple zone of the vehicle in the surroundings of the vehicle, based on a conventional physical crumple zone of the vehicle, which only develops its protective effect when the vehicle actually comes into contact with the collision object, and on developing the best possible protective effect, namely in the form of the activation of the occupant restraint device, depending on the "penetration" of a collision object into this virtual crumple zone of the vehicle.In order to detect an unavoidable collision with a sufficient degree of safety and reliability and thus ultimately to control the occupant restraint device, the invention further provides in particular that this virtual crumple zone is divided into a plurality of radial sectors, each of which has a predetermined distance from the vehicle, wherein for each sector, based on its respective distance and a predetermined activation time of the occupant restraint device, a respective relative speed limit value is predetermined and assigned to the corresponding sector, and wherein the control takes place as a function of a comparison of a determined current relative speed between the vehicle and the collision object with a relative speed limit value assigned to the current sector.

[0009] The embodiment according to the invention therefore has the advantage that it provides a method by means of which a safe and reliable detection of an unavoidable collision and thus a reliable and needs-based early control and triggering of the, in particular irreversible, occupant restraint device before the actual collision and consequently an optimal protection of an occupant are possible already in a pre-crash phase.

[0010] The detection range represents, in particular, the area in the vehicle's surroundings that can be detected or monitored by the vehicle's surroundings sensors. The detection range of the surroundings sensors advantageously covers the front of the vehicle. Preferably, the detection range covers the front, rear, and sides of the vehicle.

[0011] The virtual crumple zone corresponds to at least a partial area of ​​the detection range of the environmental sensor system and can be directly or indirectly adjacent to the vehicle, in particular to a vehicle outer skin. The radial sectors of the virtual crumple zone each represent partial areas or segments of the virtual crumple zone, wherein the radial sectors, in particular all radial sectors, advantageously have essentially the same or exactly the same radial extent with respect to the vehicle or a center of gravity of the vehicle. The distance of a respective sector from the vehicle relates in particular to the distance from a vehicle outer skin of the vehicle.

[0012] The occupant restraint device, in particular, has a predetermined, fixed activation time. Within the scope of the invention, controlling the occupant restraint device is understood to mean, in particular, activating or triggering the occupant restraint device.

[0013] The detection of the collision object in the virtual crumple zone advantageously comprises determining or validating the presence of the collision object in the virtual crumple zone and preferably also comprises determining a current sector in which the collision object is currently located. Preferably, the detection of the collision object in the virtual crumple zone comprises validating the presence of the collision object in the virtual crumple zone, which was previously classified, for example, by the environmental sensor system using an environmental model for a function of a driver assistance system of the vehicle, in particular for an ADAS function (Advanced Driver Assistance System) of the vehicle.

[0014] In an advantageous embodiment, the occupant restraint system is activated as soon as the comparison shows that the determined current relative speed for a current sector exceeds the relative speed limit assigned to that current sector. The occupant restraint system is thus activated, i.e., triggered, as soon as the determined current relative speed for or in a current sector of the virtual crumple zone is greater than the relative speed limit assigned to that current sector.

[0015] In a further advantageous embodiment, the detection of the collision object in the virtual crumple zone is carried out based on a determination of a Doppler shift as part of an evaluation of the measurement data.

[0016] The collision object is detected in the virtual crumple zone based on the Doppler effect, with the detection being carried out in particular on the basis of a detected change in a frequency between a measurement signal emitted by the environmental sensor system and a measurement signal reflected by the collision object and then received by the environmental sensor system.

[0017] In a further advantageous embodiment, the detection of the collision object in the virtual crumple zone comprises a comparison of a speed of the collision object determined based on the Doppler shift or a relative speed between the vehicle and the collision object with a parameter of the collision object determined before entering the virtual crumple zone. The parameter of the collision object is advantageously determined based on the measurement data of the environment sensors for the collision object located in the detection range of the environment sensors, but in particular not yet in the virtual crumple zone, for example based on a created environment model. The parameter of the collision object is advantageously designed as a speed and / or a relative speed and / or an angle and / or a distance and / or an estimated time until collision.

[0018] In a further advantageous embodiment, the current relative speed is determined based on a Doppler shift during an evaluation of the measurement data. Thus, the current relative speed between the vehicle and the collision object is determined based on the Doppler effect, in particular based on a detected change in frequency between a measurement signal emitted by the environment sensor system and a measurement signal reflected by the collision object and then received by the environment sensor system.

[0019] In a further advantageous embodiment, the current relative speed is calculated according to the following formula: v r = (F d · c) / (2 · F t cos(α)), where v r the relative velocity is, F d a Doppler frequency shift, c which indicates the speed of light, F tindicates a transmission frequency of a measurement signal emitted by the environmental sensor system, and α indicates an angle between a transmission direction of the emitted measurement signal and a direction of movement of the collision object. Advantageously, the angle between the transmission direction of the emitted measurement signal and the direction of movement of the collision object is assumed or predetermined as 0° in the event that this angle is unknown or cannot be determined, for example, because an environmental sensor used in the environmental sensor system is unable to determine the angle.

[0020] In a further advantageous embodiment, the virtual crumple zone is configured in the shape of a circular sector. The radial sectors each represent subregions of the circular sector-shaped virtual crumple zone and, in particular, each comprise a circular arc. The circular arc delimits a respective sector in a radial direction relative to the vehicle or a center of gravity of the vehicle, i.e., represents a sector boundary. Advantageously, the respective distance between two immediately adjacent circular arcs or sector boundaries is essentially the same or identical for all sectors.

[0021] In a further advantageous embodiment, several, in particular four, virtual crumple zones are defined in the surroundings of the vehicle and each adjacent to the vehicle. The detection range of the surroundings sensor system advantageously covers at least one further surrounding area of ​​the vehicle in addition to the front surroundings of the vehicle. The detection range preferably covers a front surrounding area, a rear surrounding area, and a side surrounding area of ​​the vehicle, with four virtual crumple zones being defined here, namely a front virtual crumple zone, a rear virtual crumple zone, a left-side virtual crumple zone, and a right-side virtual crumple zone.

[0022] In a further advantageous embodiment, the environmental sensor system is designed to monitor the surroundings of the vehicle and comprises at least one environmental sensor, wherein the at least one environmental sensor is designed as a camera, a radar sensor, a lidar sensor, an ultrasonic sensor, or an infrared sensor. The environmental sensor has a sensor detection range, wherein the sensor detection range advantageously has a, in particular fixed, opening angle and a, in particular fixed, range. If the environmental sensor system has only one environmental sensor, the sensor detection range of the environmental sensor represents the detection range of the environmental sensor system.

[0023] Advantageously, the environmental sensor system comprises a plurality of environmental sensors, wherein the plurality of environmental sensors are embodied as a camera and / or a radar sensor and / or a lidar sensor and / or an ultrasonic sensor and / or an infrared sensor. Thus, the environmental sensor system can comprise a plurality of environmental sensors of only one named sensor type, for example, a plurality of radar sensors, or a plurality of environmental sensors of different named sensor types, for example, one or more radar sensors and also one or more ultrasonic sensors. If the environmental sensor system comprises a plurality of environmental sensors, the detection range of the environmental sensor system is formed by the respective sensor detection ranges of the plurality of environmental sensors.

[0024] In a further advantageous embodiment, the occupant restraint device is designed as an irreversible occupant restraint device. Preferably, the irreversible occupant restraint device is designed as an airbag or as an irreversible seatbelt tensioner.

[0025] Furthermore, the present invention comprises a device for controlling an occupant restraint device of a vehicle in a pre-crash phase in the event of an impending collision of the vehicle with a collision object, comprising an electronic control unit which is configured to carry out a method according to the invention.

[0026] The advantages and preferred embodiments described for the method according to the invention also apply accordingly to the device according to the invention.

[0027] Advantageously, the electronic control unit is designed as an electronic control unit of the vehicle, in particular as an airbag control unit of the vehicle.

[0028] Embodiments of the invention are explained in more detail below with reference to a drawing. In the drawings: Fig. 1 shows a schematic representation of a vehicle with a device according to the invention for controlling an occupant restraint device of the vehicle, Fig. 2 shows a schematic representation of a vehicle with a device according to the invention for controlling an occupant restraint device of the vehicle in an alternative embodiment in a pre-crash phase, and Fig. 3 a flow diagram of a method according to the invention for controlling an occupant restraint device of the vehicle from Fig. 2.

[0029] Corresponding parts are always provided with the same reference symbols in all figures.

[0030] In Fig. 1 shows a schematic representation of a vehicle 1 with a device according to the invention for controlling an occupant restraint device of the vehicle 1. The vehicle 1 has an occupant and comprises an irreversible occupant restraint device designed as an airbag, an electronic control unit designed as an airbag control unit, and an environmental sensor system for monitoring the environment of the vehicle 1. The environmental sensor system and the airbag are each connected at least indirectly to the airbag control unit. The airbag has a predetermined, fixed activation time. The environmental sensor system comprises a plurality of environmental sensors, wherein the plurality of environmental sensors are each designed, for example, as a radar sensor. Each of the environmental sensors has a respective sensor detection area, each of which has a fixed aperture angle and a fixed range.The respective sensor detection areas together represent a detection area of ​​the environmental sensor system. The measurement data of the environmental sensor system are continuously monitored and evaluated via the airbag control unit while vehicle 1 is driving.

[0031] The detection range of the environment sensor system covers a front environment, a rear environment, and a side environment of the vehicle 1. Based on the detection range of the environment sensor system, four virtual crumple zones 2, 3, 4, 5 are defined, each directly adjacent to the vehicle 1, namely a front virtual crumple zone 2, a rear virtual crumple zone 3, a left-side virtual crumple zone 4, and a right-side virtual crumple zone 5. Each of the virtual crumple zones 2, 3, 4, 5 is designed in the shape of a circular sector and divided into several radial sectors 2a-2n, 3a-3n, 4a-4n, 5a-5n, which each have a predetermined distance from the vehicle. The radial sectors 2a-2n, 3a-3n, 4a-4n, 5a-5n each represent sub-areas or segments of the respective virtual crumple zone 2, 3, 4, 5 and each have a circular arc 6a-6n, where Fig. 1 only for the front virtual crumple zone 2, individual circular arcs are provided with a reference symbol 6a-6n in order not to overload the illustration. A respective circular arc 6a-6n delimits a respective corresponding sector 2a-2n, 3a-3n, 4a-4n, 5a-5n in a radial direction with respect to the vehicle 1 or a center of gravity of the vehicle 1 and thus represents a sector boundary. The respective distance between two immediately adjacent circular arcs 6a-6n or sector boundaries is essentially the same for all sectors 2a-2n, 3a-3n, 4a-4n, 5a-5n of a respective virtual crumple zone 2, 3, 4, 5.

[0032] For each sector 2a-2n, 3a-3n, 4a-4n, 5a-5n, a respective relative speed limit value is predetermined based on its respective distance, for example based on the respective distance of its respective circular arc 6a-6n, from a vehicle outer skin of the vehicle 1 facing the corresponding virtual crumple zone 2, 3, 4, 5 and the predetermined activation time of the airbag and is assigned to the corresponding sector 2a-2n, 3a-3n, 4a-4n, 5a-5n.

[0033] In Fig. Figure 2 shows a schematic representation of a vehicle 1 with a device according to the invention for controlling an occupant restraint device of the vehicle 1 in an alternative embodiment in a pre-crash phase. The vehicle 1 essentially corresponds to the vehicle shown in Fig. 1 described vehicle 1, whereby here, in contrast to the vehicle in Fig. 1, the environment sensor system comprises only an environment sensor designed as a radar sensor on the front side, the sensor detection range of which covers a frontal environment of the vehicle 1 and represents the detection range of the environment sensor system. Based on this detection range, only a frontal virtual crumple zone 2 is defined, which corresponds to the frontal virtual crumple zone 2 of the vehicle shown in Fig. 1 shown vehicle 1. In this case, Fig. 2 purely for illustration purposes, the distances xa-xn are shown, on the basis of which the respective relative speed limits of the respective sectors 2a-2n are predetermined.

[0034] The vehicle 1 moves forward in the direction of the arrow at the speed v1, wherein with respect to the vehicle 1 from the front a collision object 7 designed as another vehicle (different from the vehicle 1) moves forward in the direction of the arrow at the speed v2 towards the vehicle 1, so that a frontal impact is unavoidable.

[0035] In Fig. 3 is a flowchart of a method 100 according to the invention for controlling the occupant restraint device of the vehicle 1 from Fig. 2, wherein the method 100 is performed during the pre-crash phase of the unavoidable frontal impact.

[0036] In a step 101, the collision object 7 located within the detection range of the environment sensors is first detected based on the measurement data from the environment sensors. This detection can be performed by the airbag control unit or by another control unit or another device of the vehicle based on a created environment model, for example, by a control unit or device of a driver assistance system of the vehicle, in particular an Advanced Driver Assistance System of the vehicle. In this case, parameters such as speed or relative speed, angle, distance, and the estimated time until the collision or frontal impact are also determined.

[0037] In a subsequent step 102, the "penetration" or presence of the collision object 7 into the front-side virtual crumple zone 2 is detected based on a determination of a Doppler shift as part of an evaluation of the measurement data. Thus, the collision object 7 is detected in the front-side virtual crumple zone 2 based on the Doppler effect, with the detection being performed, for example, based on a detected change in frequency between a radar signal emitted by the radar sensor and a radar signal reflected by the collision object 7 and then received by the radar sensor.In this case, a comparison is carried out between a speed of the collision object 7 or a relative speed between the vehicle 1 and the collision object 7 determined on the basis of the determined Doppler shift and one or more of the parameters determined in step 101, wherein one or more of the parameters determined in step 101 is / are verified.

[0038] Then, in a step 103, a current relative speed between the vehicle 1 and the collision object 7 for a current sector 2a-2n in which the collision object is currently located is continuously calculated according to the following formula: v r = (F d · c) / (2 · F t cos(α)), where v r the relative velocity is, F d a Doppler frequency shift, c which indicates the speed of light, F tindicates a transmission frequency of a radar signal emitted by the environmental sensor system and α indicates an angle between a transmission direction of the emitted radar signal and a direction of movement of the collision object 7.

[0039] In a step 104, a comparison of the determined current relative speed with a relative speed limit value assigned to the current sector 2a-2n is continuously carried out.

[0040] As soon as the comparison in step 104 shows that the determined current relative speed for a current sector 2a-2n exceeds the relative speed limit value assigned to this current sector 2a-2n, the airbag is activated or triggered in a step 105.

[0041] Such a design enables safe and reliable detection of an unavoidable collision already in a pre-crash phase and thus reliable and needs-based early activation or triggering of an irreversible occupant restraint system before the actual collision and consequently optimal protection of a vehicle occupant.

Claims

[1] Method (100) for controlling an occupant restraint device of a vehicle (1) in a pre-crash phase in the event of an impending collision of the vehicle (1) with a collision object (7) using measurement data from an environmental sensor system of the vehicle (1), wherein, based on a detection range of the environmental sensor system, a virtual crumple zone (2-5) is defined in an environment of the vehicle (1) and adjacent to the vehicle (1), wherein the virtual crumple zone (2-5) is divided into a plurality of radial sectors (2a-2n, 3a-3n, 4a-4n, 5a-5n) which have a respective predetermined distance (xa-xn) from the vehicle (1), wherein for each sector (2a-2n, 3a-3n, 4a-4n, 5a-5n) based on its respective distance (xa-xn) and a predetermined activation time of the occupant restraint device, a respective relative speed limit value predetermined and assigned to the corresponding sector (2a-2n, 3a-3n, 4a-4n, 5a-5n),and wherein the method (100) comprises the following steps: - detection (102) of the collision object (7) in the virtual crumple zone (2-5), - determining (103) a current relative speed between the vehicle (1) and the collision object (7) for a current sector (2a-2n, 3a-3n, 4a-4n, 5a-5n) in which the collision object (7) is currently located, - performing (104) a comparison of the determined current relative speed with a relative speed limit value assigned to the current sector (2a-2n, 3a-3n, 4a-4n, 5a-5n), and - controlling (105) the occupant restraint device in dependence on the comparison. [2] Method (100) according to claim 1, wherein the actuation (105) of the occupant restraint device takes place as soon as the comparison shows that the determined current relative speed for a current sector (2a-2n, 3a-3n, 4a-4n, 5a-5n) exceeds the relative speed limit value assigned to this current sector (2a-2n, 3a-3n, 4a-4n, 5a-5n). [3] Method (100) according to claim 1 or 2, wherein the detection (102) of the collision object (7) in the virtual crumple zone (2-5) is based on a determination of a Doppler shift as part of an evaluation of the measurement data. [4] Method according to claim 3, wherein the detection (102) of the collision object (7) in the virtual crumple zone (2-5) comprises a comparison of a speed of the collision object (7) or relative speed between the vehicle (1) and the collision object (7) determined on the basis of the Doppler shift with a parameter of the collision object (7) determined before entering the virtual crumple zone (2-5). [5] Method (100) according to one of the preceding claims, wherein the current relative speed is determined based on a determination of a Doppler shift in the context of an evaluation of the measurement data. [6] Method (100) according to claim 5, wherein the current relative speed is calculated according to the following formula: v r = (F d · c) / (2 · F t cos(α)), where v r the relative velocity is, F da Doppler frequency shift, c which indicates the speed of light, F t indicates a transmission frequency of a measurement signal emitted by the environmental sensor system and α indicates an angle between a transmission direction of the emitted measurement signal and a direction of movement of the collision object (7). [7] Method (100) according to one of the preceding claims, wherein the virtual crumple zone (2-5) is formed in the shape of a circular sector. [8] Method (100) according to one of the preceding claims, wherein several, in particular four, virtual crumple zones (2-5) are defined in the surroundings of the vehicle (1) and each adjacent to the vehicle (1). [9] Method (100) according to one of the preceding claims, wherein the environmental sensor system is designed to monitor an environment of the vehicle (1) and comprises at least one environmental sensor, wherein the at least one environmental sensor is designed as a camera or a radar sensor or a lidar sensor or an ultrasonic sensor or an infrared sensor. [10] Method (100) according to one of the preceding claims, wherein the occupant restraint device is designed as an irreversible occupant restraint device, preferably as an airbag or as an irreversible seatbelt tensioner. [11] Device for controlling an occupant restraint device of a vehicle (1) in a pre-crash phase in the event of an impending collision of the vehicle (1) with a collision object (7), comprising an electronic control unit which is designed to carry out a method (100) according to one of the preceding claims.

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