Device and method for determining the mass of a vehicle occupant

Abstract

Device (6) for determining the mass of an occupant (2) of a vehicle (1), wherein the device (6) comprises: - a vehicle acceleration detection device (7) configured to determine a vehicle acceleration vector (24) that describes an acceleration experienced by the vehicle (1); - an occupant acceleration detection device (10) configured to determine an occupant acceleration vector (26) describing an acceleration experienced by the occupant (2); and - an evaluation device (13) which is designed to determine a vehicle force vector (21) that describes a force acting on the vehicle (1) based on the determined vehicle acceleration vector (24), to project the vehicle force vector (21) onto the occupant (2) and to determine mass information (36) that describes a mass of the occupant (2) from the projected vehicle force vector (22) and the determined occupant acceleration vector (26).

Description

[0001] The invention relates to a device and a method for determining a mass of an occupant of a vehicle.

[0002] A vehicle, for example a motor vehicle, may have an inertial measurement unit (IMU), which may alternatively be referred to as an inertial measurement unit. The inertial measurement unit is located, for example, at the location of the vehicle's center of gravity and can be used to improve comfort functions and / or active safety functions of the vehicle. Alternatively or additionally, the vehicle may have an acceleration sensor. The acceleration sensor may, for example, be designed to detect external vibrations of the vehicle while the vehicle is traveling.

[0003] The vehicle can further be configured to detect the presence of a living being, such as a person and / or an animal, in the vehicle interior (life presence detection, LPD). Such detection makes it possible, for example, to check whether an occupant has remained in the vehicle interior in a switched off vehicle in which the vehicle ignition is off. If the presence of a person as an occupant in the vehicle interior has been detected, further information about the person may be of interest, such as their mass, so that, for example, a mass-dependent and thus individualized adjustment of a vehicle's airbag can be carried out.

[0004] It is the object of the invention to provide a solution by means of which a mass of an occupant of a vehicle can be reliably determined.

[0005] The problem is solved by the subject matter of the independent patent claims.

[0006] A first aspect of the invention relates to a device for determining the mass of a vehicle occupant. The occupant is, for example, a person, such as a driver, a passenger, and / or a person sitting in a rear seat of the motor vehicle. The vehicle is, for example, a motor vehicle, such as a passenger car, a truck, and / or a passenger bus.

[0007] The device comprises a vehicle acceleration detection device, an occupant acceleration detection device, and an evaluation device. The vehicle acceleration detection device is designed to determine a vehicle acceleration vector. In other words, the vehicle acceleration vector can be determined using the vehicle acceleration detection device. The vehicle acceleration vector describes an acceleration experienced by the vehicle. The vehicle acceleration vector indicates, for example, the acceleration of the vehicle in three spatial directions. The three spatial directions could, for example, be specified in a coordinate system of the vehicle acceleration detection device, which corresponds, for example, to a device coordinate system of the device. The vehicle acceleration vector is typically specified in Cartesian coordinates.The vehicle acceleration vector preferably indicates the acceleration of the vehicle at a location of a center of mass of the vehicle, in particular if the vehicle acceleration detection device is arranged at the location of the center of mass in the vehicle.

[0008] The occupant acceleration detection device is designed to determine an occupant acceleration vector that describes an acceleration experienced by the occupant. In other words, the occupant acceleration vector can be determined using the occupant acceleration detection device. The occupant acceleration vector indicates, for example, in Cartesian coordinates, the acceleration experienced by the occupant at their location in the vehicle. The occupant acceleration vector indicates the acceleration acting at a center of mass of the occupant, which can be referred to, for example, as the occupant's center of body mass. It can be provided that the occupant acceleration detection device is different from the vehicle acceleration detection device.

[0009] The device therefore preferably provides two different devices, each of which determines an acceleration, wherein the two determined accelerations can differ from one another, since one of the two devices determines the vehicle acceleration vector and the other the occupant acceleration vector.

[0010] The evaluation device is designed to determine a vehicle force vector based on the determined vehicle acceleration vector. The vehicle force vector describes a force acting on the vehicle. The vehicle force vector describes, in particular, the force acting at the vehicle's center of mass. In addition, the evaluation device is designed to project the vehicle force vector onto the occupant. This results in a projected vehicle force vector that does not describe the force acting at the vehicle's center of mass, but rather the force that actually acts on the occupant at the occupant's location. The projected vehicle force vector can therefore alternatively be referred to as an occupant force vector, which describes the force acting on the occupant at their location. The force vector is projected using known vector projection methods.The evaluation device is also designed to determine mass information from the projected vehicle force vector and the determined occupant acceleration vector, wherein the mass information describes a mass of the occupant. The mass information can be in the form of mass data, wherein the mass data in particular has at least one mass value. The relationship between the projected vehicle force vector, i.e., the force acting on the occupant, and the occupant acceleration vector, i.e., the acceleration acting on the occupant, is ultimately determined by Newton's laws. Accordingly, the force vector can be calculated from the product of the acceleration vector and the mass of the body on which the force and acceleration act.Ultimately, the evaluation device can be used to determine the vehicle force vector based on the determined vehicle acceleration vector, project the vehicle force vector onto the occupant, and determine the mass information from the projected vehicle force vector and the determined occupant acceleration vector.

[0011] The mass information can simply be an estimate of the actual mass of the occupant, with a distinction being made between several different mass ranges. The different mass ranges can be made available for further analysis by the analysis device and / or another control device of the vehicle. For example, mass information greater than 0 kilograms and less than 10 kilograms can be used to determine a toddler, mass information between 10 kilograms and 50 kilograms can be used to determine a child, and mass information greater than 50 kilograms can be used to determine an adult. A child is defined here as a person from the age of four up to the age of 18, i.e. the child could be an adolescent, for example. A toddler is also understood to be a newborn or an infant, i.e. a person under four years of age.Based on the determined mass information, a vehicle's airbag function can be automatically deactivated, especially locally, if the detected person is, for example, a small child, and / or a time-dependent warning message can be provided if a small child or infant is detected left behind in a switched-off vehicle. Ultimately, the determined mass information is thus provided for other vehicle functions.

[0012] By recording both the acceleration acting on the vehicle and the acceleration acting on the occupant and subsequently evaluating the corresponding data to determine the mass information, a device is provided by which the mass of the vehicle occupant can be reliably determined. The device can also be based on devices already present in the vehicle, since devices for detecting acceleration and the evaluation device are typical for the vehicle. The device is therefore particularly simple and cost-effective to implement.

[0013] The device according to the invention can be understood as a device arrangement, wherein the device arrangement comprises the device already described as well as the vehicle with at least one occupant. Furthermore, the first aspect of the invention can be understood as a system for determining the mass of a vehicle occupant.It is provided that the system determines a vehicle acceleration vector, which describes an acceleration experienced by the vehicle, by means of a vehicle acceleration detection device; determines an occupant acceleration vector, which describes an acceleration experienced by the occupant; and determines a vehicle force vector, which describes a force acting on the vehicle, by means of an evaluation device, based on the determined vehicle acceleration vector, projects the vehicle force vector onto the occupant, and determines mass information, which describes a mass of the occupant, from the projected vehicle force vector and the determined occupant acceleration vector.

[0014] An advantageous embodiment provides that the occupant acceleration detection device is designed as a radar sensor and / or camera. The occupant acceleration vector can thus be determined radar-based and / or camera-based or image-based. The radar sensor can, for example, have at least one transmitting antenna and at least one receiving antenna, in particular a plurality of receiving antennas. The radar sensor can, for example, be arranged centrally in a vehicle longitudinal direction and a vehicle transverse direction on an inner wall of a ceiling of the vehicle in the vehicle interior. The radar sensor is preferably arranged such that all vehicle seats in the vehicle interior can be at least partially detected by means of the radar sensor. The camera can be designed as a vehicle interior camera, which can, for example, be arranged spatially close to the radar sensor, in particular at the same location as the radar sensor.Alternatively or additionally, the camera can be positioned, for example, in a front area of ​​the vehicle on a ceiling area there. The camera is designed to provide static and / or moving image data that describe the vehicle interior, in particular at least partially a region of the respective vehicle seat in the vehicle interior. The provided image data can be referred to as camera data. Alternatively or additionally, a plurality of spatially spaced radar sensors and / or cameras can be provided in the vehicle interior. Ultimately, the occupant acceleration information is therefore determined from measurement data recorded in the vehicle interior by the radar sensor and / or the camera.Since both the radar sensor and the camera can be found in the vehicle interior in many vehicles, a particularly cost-effective and easy-to-implement design of the occupant acceleration detection device is chosen for the device.

[0015] Furthermore, one exemplary embodiment provides that the vehicle acceleration detection device is designed as an acceleration sensor and / or an inertial measurement unit. The inertial measurement unit (IMU) can alternatively be referred to as an inertial measurement unit or inertial sensor. The inertial measurement unit has, for example, a plurality of inertial sensors, such as acceleration sensors and / or yaw rate sensors. The acceleration sensor and / or the inertial measurement unit can be arranged, for example, in the region of a center of mass of the vehicle. Alternatively or additionally, at least one of the two possible vehicle acceleration detection devices can be arranged spatially close to and / or at the same location as the occupant acceleration detection device on the ceiling of the vehicle.The vehicle acceleration detection device can, for example, comprise a plurality of acceleration sensors in the vehicle, which can be arranged spatially spaced from one another. Since the acceleration sensor and / or the inertial measurement unit are often provided as standard in the vehicle, the described embodiment provides a particularly cost-effective and easy-to-implement vehicle acceleration detection device for the device.

[0016] Furthermore, one embodiment provides that the device has an occupant presence detection device. The occupant presence detection device is, in particular, a pressure sensor and / or a seat belt buckle sensor. The pressure sensor is arranged in a vehicle seat of the vehicle. The pressure sensor is designed to detect whether or not an occupant is sitting on the vehicle seat. The pressure sensor can determine this by evaluating pressure information it detects, which describes a pressure acting on the vehicle seat. The seat belt buckle sensor is, for example, integrated into a seat belt buckle or at least assigned to it. The seat belt buckle sensor is designed to detect whether a seat belt assigned to the vehicle seat is arranged in a closed position or in an open position in which the seat belt and the seat belt buckle are spatially separated from one another.In the closed position, the seat belt is locked into the buckle, meaning the buckle secures the seat belt. The closed position therefore indicates that a person is sitting in the vehicle seat, as they are buckled in using the seat belt and buckle.

[0017] The occupant presence detection device is designed to detect presence information and provide it to the evaluation device. The presence information describes the presence of the occupant at a location assigned to the occupant presence detection device, for example, on the vehicle seat in which the pressure sensor and / or on which the seat belt buckle with the seat belt buckle sensor is arranged. The presence information can be detected in the form of presence data. The occupant presence detection device can therefore detect the presence of the person at a location in the vehicle assigned to the occupant presence detection device. The evaluation device can use the presence information for further functions or evaluation steps if necessary.This makes it possible to initially determine whether an occupant is actually present in the vehicle and at least to estimate their location. The occupant presence detection system is also a typical vehicle component, thus contributing to the development of a device for determining the occupant's mass that can be implemented in the vehicle with minimal effort.

[0018] A further aspect of the invention relates to a vehicle having a vehicle interior in which a device as described above is arranged. The exemplary embodiments described in connection with the device according to the invention, individually and in combination with one another, apply accordingly, where applicable, to the vehicle according to the invention. The vehicle is, for example, a motor vehicle, for example a passenger car, a truck, and / or a passenger bus. Alternatively or additionally, the vehicle may be another land vehicle, such as a rail vehicle, an aircraft, and / or a watercraft.

[0019] Furthermore, one aspect of the invention relates to a method for determining the mass of a vehicle occupant. The method comprises the following steps: determining a vehicle acceleration vector that describes an acceleration experienced by the vehicle using a vehicle acceleration detection device; and determining an occupant acceleration vector that describes an acceleration experienced by the occupant using an occupant acceleration detection device. The occupant acceleration detection device is, in particular, a device different from the vehicle acceleration detection device.Furthermore, the method provides that an evaluation device determines a vehicle force vector that describes a force acting on the vehicle based on the determined vehicle acceleration vector, projects the determined vehicle force vector onto the occupant, and determines mass information that describes a mass of the occupant from the projected vehicle force vector and the determined occupant acceleration vector. The exemplary embodiments described in connection with the device according to the invention, individually or in combination with one another, apply accordingly, where applicable, to the method according to the invention. Furthermore, combinations of the exemplary embodiments of the device according to the invention described below, individually or in combination, apply analogously as exemplary embodiments of the method according to the invention.

[0020] One embodiment of the method according to the invention provides that the occupant acceleration detection device is designed as a radar sensor, by means of which a point cloud characteristic of the occupant is detected. The occupant acceleration vector is determined by evaluating the detected point cloud. In other words, when a radar sensor is used as the occupant acceleration detection device, the individual occupant appears as a point cloud in the radar device's measurement data. The point cloud is thus characteristic of the occupant. The detected point cloud is evaluated to calculate the acceleration acting on the occupant. The evaluation using the radar sensor can be designed for static and / or moving objects. Ultimately, a typical radar sensor can thus be used to determine the occupant acceleration vector.

[0021] Furthermore, one embodiment provides that the characteristic point cloud is continuously recorded. In addition, speed change information describing a speed change between at least two point clouds recorded one after the other is determined, and the occupant acceleration vector is determined from the determined speed change information. Based on changes in speed between successive frames, the acceleration experienced by the occupant can thus be calculated. Preferably, the change, for example, in the speed experienced by the occupant is taken into account across several successive point clouds in order to calculate the acceleration. The speed change information can be provided in the form of data. Therefore, for example, it can alternatively be provided that speed change data is determined.

[0022] In one exemplary embodiment, it can also be provided that a sub-region of the acquired point cloud is determined in which the acquired point cloud has a highest signal-to-noise ratio compared to the rest of the point cloud. The determined sub-region is assumed to be the torso center of mass of the occupant's torso. The vehicle force vector is then projected onto a location of the assumed torso center of mass, i.e., onto the sub-region in which the determined torso center of mass is located. The occupant's torso can alternatively be referred to as the occupant's torso. The torso is the part of the occupant that is neither the head, neck, nor limbs. The described procedure is based on the realization that the vehicle occupant can be viewed, for simplicity, as a rigid body. By evaluating measurement data from the radar sensor, a center of the occupant's body mass, i.e., a body center of mass, can be estimated.For this purpose, the center of mass of the torso is first determined, as this can be particularly easily detected in the measurement data from the radar sensor. For example, the measurement data across the entire Doppler spectrum is viewed in a distance grid that divides, for example, at least the distances assigned to the acquired point cloud into several sub-areas. Within this distance grid, the measurement data with the highest signal-to-noise ratio compared to the remaining measurement data are located at a specific location. This location in the distance grid corresponds to the location of the sub-area. Thus, by comparing the individual signal-to-noise ratios, a center of the occupant's torso is determined. These high signal-to-noise ratios can be detected particularly when the occupant is moving.A static object in a vehicle typically does not have a consistently high signal-to-noise ratio, so by evaluating the signal-to-noise ratio, it is also possible to differentiate, for example, whether it is actually an occupant who may be moving, or a static object, such as an object located in the vehicle. Thus, in addition to the occupant acceleration vector, the location of the occupant can ultimately be determined using the radar sensor. This location, in turn, is relevant for projecting the determined vehicle force vector onto the occupant, as it is the location onto which the vehicle force vector should be projected. The data from the radar sensor can thus be evaluated in a particularly versatile manner within the framework of the method.

[0023] Alternatively or additionally, the center of the torso can be determined using the acquired point cloud of moving and / or static measurement points in a three-dimensional coordinate system. For example, the areas known in advance to be possible seating positions are evaluated. In these areas, the density of the point cloud and / or the signal-to-noise ratio are evaluated to determine seat occupancy and / or the center of the torso.

[0024] In addition, one embodiment provides for the determination of a further sub-region of the acquired point cloud in which the acquired point cloud has a second-highest signal-to-noise ratio compared to the rest of the point cloud. The determined further sub-region is assumed to be the center of mass of the occupant's head. Taking into account the locations of the assumed center of mass of the torso and the assumed center of mass of the head, a body of the occupant can be modeled, i.e., determined. A center of mass of the modeled body is determined, and the vehicle force vector is projected onto the location of the determined center of mass of the body. The previously described method based on the center of mass of the torso can thus be further refined by taking into account another local center of mass of the occupant's body.Thus, not only the sub-region of the point cloud with the highest signal-to-noise ratio is considered, but also the sub-region with the second-highest signal-to-noise ratio. The occupant is then assumed to be composed of two rigid bodies: the rigid body of the torso and the rigid body of the head. This increases the accuracy of the location to which the vehicle force vector is projected, since the estimates of the locations of the head and torso allow the overall center of mass of the occupant to be modeled more accurately than by considering only the torso center of mass.The modeling of the body can be based, for example, on machine learning methods, for example on an artificial neural network to which information on typical relationships and arrangements of individual centers of mass of an occupant to one another, such as the center of mass of the torso and / or the center of mass of the head, has been provided as training data.

[0025] In a further exemplary embodiment, the occupant acceleration detection device is designed as a camera. Camera data is captured by means of the camera. The camera data can alternatively be referred to as camera information, which describes an environment of the camera. The camera data describes at least two images of the occupant captured one after the other. These images can be static and / or moving. The images of the occupant can alternatively be referred to as images of the occupant. The occupant acceleration vector is determined by evaluating the captured camera data. Thus, for example, a displacement of the occupant over time, i.e., between at least two images of the occupant captured one after the other, can be evaluated in order to be able to estimate the occupant acceleration vector.The camera data can be acquired alternatively or in addition to the characteristic point cloud captured by the radar device. It is therefore possible, for example, for the acceleration vector to be determined using both radar-based and camera-based methods, thus providing a particularly reliable determination of the occupant acceleration vector. For example, in this case, an average of the radar-based occupant acceleration vector and the camera-based occupant acceleration vector can be considered as the determined occupant acceleration vector.

[0026] Furthermore, one embodiment provides that, when evaluating the camera data, occupant speed change information is determined, which describes a change in the occupant's speed between the at least two images acquired one after the other. The occupant acceleration vector is then determined from the determined occupant speed change information. The occupant speed change information is preferably provided in the form of data. As an alternative to the occupant speed change information, occupant speed change data can be determined. Thus, the displacements between the individual images are used to determine the occupant's speed, with a change in this speed across multiple images, i.e., across multiple images, allowing the acceleration experienced by the occupant to be calculated.The calculation is based on the physical relationship between speed and acceleration. The calculation of the occupant speed change information from the camera data is based, for example, on image processing methods. Machine learning methods can also be used, for example, an appropriately trained artificial neural network. The corresponding evaluation algorithms for determining both the speed change information and the occupant speed change information can be stored in the evaluation device. In a vehicle without a radar sensor in the vehicle interior and equipped only with a camera in the vehicle interior, the occupant's mass can still be determined using this method without retrofitting.

[0027] According to an additional exemplary embodiment, vehicle mass information is taken into account when determining the vehicle force vector. The vehicle mass information describes a vehicle mass of the vehicle. The vehicle mass information can be provided in the form of data. In other words, vehicle mass data can be taken into account during the determination. The vehicle mass information can, for example, be provided in advance. In the evaluation device, an entry describing the vehicle mass of the vehicle can then be stored, for example in a memory unit. The vehicle mass can, for example, be determined based on an assignment of the vehicle to a specific vehicle model and / or vehicle type. The provided vehicle mass information can, for example, be an unladen mass of the vehicle.In this case, any additional mass of the vehicle caused by the occupant and / or other objects located in the vehicle may be disregarded. The provided vehicle mass information may also depend on the fill level of a fuel tank of the vehicle, if the vehicle has a fuel tank.

[0028] Alternatively or additionally, the vehicle mass information can be acquired by the vehicle itself via an internal control unit with a connected database and / or by means of a mass acquisition device. The mass acquisition device can have at least one mass sensor, which is arranged, for example, in a trunk of the vehicle and is designed to detect and provide a mass of at least one object in the trunk. Together with the stored vehicle mass of the vehicle, which can be an unladen vehicle mass of the vehicle, the current vehicle mass information can be estimated more accurately than the stored vehicle mass. Alternatively or additionally, the mass acquisition device can be a device external to the vehicle, which is designed, for example, as a scale for a truck or another vehicle, onto which the vehicle can drive.Current vehicle mass information can be determined by the vehicle-external device and made available, for example, to the vehicle's evaluation device via a wired or wireless communication connection.

[0029] If the vehicle mass information is known, the vehicle force vector can be calculated by multiplying the vehicle acceleration vector by the vehicle mass information. This allows the vehicle force vector to be actually determined from the determined and / or provided information.

[0030] Furthermore, one embodiment provides for a correction algorithm to be applied to the vehicle acceleration vector and / or the vehicle force vector. By applying the correction algorithm, the effect of vibrations and / or motion shocks on the vehicle acceleration vector and / or vehicle force vector can be at least reduced. Vibrations and / or motion shocks are observed, for example, while the vehicle is traveling, for example, whenever the vehicle is traveling on an uneven surface, such as a cobblestone road.The correction algorithm can have at least one rule that specifies a limit value, so that by applying the rule, the vehicle acceleration vector and / or the vehicle force vector, in particular the measurement data underlying the vehicle acceleration vector and / or the vehicle force vector, are adjusted in such a way that effects due to the currently occurring vibrations, which are typically in the low-frequency range, and / or other movement impulses can be at least reduced and preferably completely eliminated. In other words, low-frequency vibrations or movement impulses are ultimately filtered out, so that there is no undesired influence, and in particular no distortion, of the acceleration and force vector due to the vibrations or other movement impulses of the vehicle.The correction algorithm is provided to the evaluation unit and is, for example, a computer code, the application of which allows the evaluation unit to specify the corresponding limit value. This allows the vehicle acceleration vector and / or the vehicle force vector to be provided with the appropriate adjustment.

[0031] According to one embodiment, the device comprises an occupant presence detection device. The occupant presence detection device is, in particular, a pressure sensor and / or a seatbelt buckle sensor. Presence information describing the presence of the occupant at a location assigned to the occupant presence detection device is detected by the occupant presence detection device. The mass information is only determined if the occupant is present according to the detected presence information. In other words, the determination of the vehicle acceleration vector and / or the occupant acceleration vector and / or the steps for determining the mass information performed by the evaluation device only take place if the occupant is present.Based on the data from the occupant presence detection device, it is first confirmed that an occupant or an object is actually positioned on a vehicle seat. If, for example, the detected presence information indicates that no occupant and / or object is present, the further procedure can be omitted, making the method particularly resource-efficient.

[0032] In addition, one embodiment provides that the detected presence information is taken into account when projecting the vehicle force vector onto the occupant. The presence information, in particular, comprises location information that describes the location assigned to the occupant presence detection device. Thus, the occupant's center of mass can be estimated based solely on the position of the vehicle seat on which the occupant is sitting. The location information describes, for example, in the form of a coordinate, a position and / or a position range within the vehicle that is assigned to the vehicle seat. The location information can be provided in the form of data. The location information can therefore alternatively be referred to as location data.The center of mass of the occupant, onto which the vehicle force vector is projected, can thus be determined based on the presence information and / or based on the above-described evaluation of the sub-areas with the highest and / or second-highest signal-to-noise ratio. This provides two different options for determining the location to which the vehicle force vector is projected. This makes the method particularly versatile. If, for example, no occupant presence detection device is provided in the vehicle, location detection based on radar data can be used.However, if, for example, the occupant acceleration vector is determined using a camera, the occupant's center of mass, and thus the location to which the vehicle force vector is projected, can still be determined and taken into account without a radar sensor in the vehicle interior, taking into account the data from the occupant presence detection device. Furthermore, this can contribute to resource conservation, as the method can be focused on the areas of the vehicle where an occupant or at least an object on a vehicle seat is expected.

[0033] It should also be noted that the method for determining the occupant's mass is performed continuously while the vehicle is traveling and is not intended solely for a momentary event, such as an accident or other abrupt deceleration of the vehicle. It is therefore assumed that the occupant is continuously and therefore constantly detected by the occupant presence detection device, and that the vehicle is continuously detected by the vehicle acceleration detection device. When estimating the mass information, a weighted average of several consecutive detections, for example, of the occupant acceleration vectors or rotation vectors, can be taken into account.

[0034] It can also be provided that, as an additional degree of freedom, the angular velocity of a yaw, pitch, and roll axes is checked using the inertial measurement unit in order to reliably project the vehicle force vector onto the occupant's center of mass. This is compared with the radar sensor's update rate to determine whether extreme values ​​(spikes) in the magnitude of the acceleration vector are suitable for use within the method. This makes the method even more reliable.

[0035] A further aspect relates to a method for determining a mass of an occupant of a vehicle, the method comprising the following steps: providing a vehicle acceleration vector that describes an acceleration experienced by the vehicle; providing an occupant acceleration vector that describes an acceleration experienced by the occupant; and by means of an evaluation device: determining a vehicle force vector that describes a force acting on the vehicle based on the determined vehicle acceleration vector; projecting the determined vehicle force vector onto the occupant; and determining mass information that describes a mass of the occupant from the projected vehicle force vector and the determined occupant acceleration vector.

[0036] One aspect of the invention relates to the evaluation device for the apparatus. The evaluation device can comprise a data processing device or a processor device. The processor device can comprise at least one microprocessor, microcontroller, FPGA (field programmable gate array) and / or at least one DSP (digital signal processor). Furthermore, the processor device can comprise program code which, when executed by the processor device, is configured to carry out the method according to the invention or an exemplary embodiment of the method according to the invention or a combination of exemplary embodiments of the method according to the invention. The program code can be comprised of a computer program product, i.e., a computer program. The program code can be stored in a data memory of the processor device.

[0037] The evaluation device is, for example, a control device of the vehicle. Alternatively or additionally, the evaluation device can be a separate component installed in the vehicle. Alternatively or additionally, the evaluation device can be an external component that exchanges data with a communication interface of the vehicle. The evaluation device can be comprised of the vehicle acceleration detection device and / or the occupant acceleration detection device. The evaluation device can have a plurality of evaluation units, which are, in particular, spatially separated from one another, so that individual method steps of the evaluation device can take place in different evaluation units.

[0038] Furthermore, one aspect of the invention can relate to a computer-readable storage medium, comprising instructions which, when executed by a computer or a computer network, such as the evaluation device, cause the computer to carry out the method according to the invention. The storage medium can, for example, be designed at least partially as a non-volatile data memory (e.g., as a flash memory and / or as an SSD - solid state drive) and / or at least partially as a volatile data memory (e.g., as a RAM - random access memory). The computer or computer network can provide a processor circuit with at least one microprocessor. The instructions can be provided as binary code or assembler and / or as source code of a programming language (e.g., C).

[0039] Showing: Fig. 1 is a schematic representation of a vehicle with a device for determining a mass of an occupant of the vehicle; Fig. 2 a schematic plan view of force vectors acting in the vehicle; Fig. 3 shows a schematic representation of a signal flow graph of a method for determining a mass of an occupant of a vehicle; Fig. 4 a schematic plan view of occupants of a vehicle with sketched head mass centers; and Fig. 5 a schematic side view of occupants of a vehicle with sketched torso mass centers and head mass centers.

[0040] Fig. 1 shows a vehicle 1, which is embodied here as a motor vehicle, in particular as a passenger car. The vehicle 1 accommodates two passengers 2, one of whom is positioned as the driver in a driver's seat 3 and the other as the front passenger in a front passenger seat 4. The vehicle 1 also has several rear seats 5. Alternative numbers and arrangements of the passengers 2 in the vehicle 1 are possible. The arrangement of the two passengers 2 in a front area of ​​the vehicle 1 described here is to be understood purely as an example.

[0041] The vehicle 1 has a device 6 for determining the mass of an occupant 2 of the vehicle 1. The device 6 has a vehicle acceleration detection device 7. An acceleration sensor 8 and an inertial measuring unit 9, which can alternatively be referred to as an inertial sensor, are outlined here as the vehicle acceleration detection device 7. The two options for the vehicle acceleration detection device 7 are arranged here, by way of example, approximately centrally in both a longitudinal direction (x-direction) and a transverse direction (y-direction) of the vehicle 1. At least the inertial measuring unit 9 is preferably arranged at the location of a vehicle center of mass of the vehicle 1.

[0042] The device 6 also has an occupant acceleration detection device 10. The occupant acceleration detection device 10 is designed, for example, as a radar sensor 11 and / or a camera 12. Both the radar sensor 11 and the camera 12 are designed to detect a vehicle interior of the vehicle 1. They are therefore positioned, for example, approximately centrally in the longitudinal and transverse directions in the region of a ceiling of the vehicle 1, i.e., for example, integrated into a vehicle headliner of the vehicle 1. In particular, a position of the radar sensor 11 and the camera 12 is selected such that all possible occupants 2 of the vehicle 1 can be detected by means of the radar sensor 11 or the camera 12. Therefore, both the driver's seat 3 and the front passenger seat 4, as well as the rear seats 5, are at least partially within a detection range of the radar sensor 11 or the camera 12.

[0043] The device 6 also has an evaluation device 13. The evaluation device 13 can be a component of the vehicle 1, i.e., for example, a control device or another type of computing device of the vehicle 1. The evaluation device 13 can have at least one microprocessor and / or microcontroller and can thus be configured, for example, as a computer.

[0044] The vehicle 1 can have an occupant presence detection device 14, which is sketched here as an example for the front passenger seat 4. The occupant presence detection device 14 can have a pressure sensor 15 integrated into the front passenger seat 4 and / or a seat belt buckle sensor 16 for a seat belt 39 of the front passenger seat 4. The seat belt buckle sensor 16 is designed to detect a closed position of the seat belt 39. The pressure sensor 15 can detect a pressure exerted on the front passenger seat 4 and thus determine whether, for example, an occupant 2 or another object is positioned on the front passenger seat 4 or not. Analogously, the occupant presence detection device 14 can be provided for the driver seat 3 and / or a respective rear seat 5 in the vehicle 1 (not sketched here).

[0045] In Fig. Figure 2 shows a plan view of the two occupants 2 in the vehicle 1. The inertial measurement unit 9 is arranged at the location of the vehicle's center of mass. Also shown is, for example, the acceleration sensor 8, which is comprised, for example, of an acceleration measuring device. The acceleration sensor 8 can be arranged at any location in the vehicle 1. For example, it can be arranged spatially close to the occupant acceleration detection device 10.

[0046] In Fig. 2 shows several coordinate systems, namely an acceleration sensor coordinate system 17, which represents a local coordinate system of the acceleration sensor 8, a measuring unit coordinate system 18, which represents a local coordinate system of the inertial measuring unit 9, and occupant coordinate systems 19 for each of the two occupants 2. The occupant coordinate systems 19 each represent the local coordinate system of the occupant 2. The respective occupant coordinate system 19 has an origin in a center of mass 20 of the respective occupant 2. Each of the outlined coordinate systems has an x-axis, a y-axis, and a z-axis, i.e., different axes for Cartesian coordinates.

[0047] In Fig. 2, several force vectors are also sketched. Two of the force vectors are a vehicle force vector 21, which was determined either using the measurement data of the acceleration sensor 8 or using the measurement data of the inertial measurement unit 9. The two vehicle force vectors 21 shown here therefore differ, for example, in their magnitude and direction, which is due to the fact that they are specified in their respective local coordinate systems, i.e., in the acceleration sensor coordinate system 17 and the measurement unit coordinate system 18, respectively. Fig. 2, a projected vehicle force vector 22 is sketched, which represents a projection of the vehicle force vector 21 of the acceleration sensor 8 and / or the inertial measuring unit 9 onto the center of mass 20 of the respective occupant 2. The vehicle force vector 21 in the acceleration sensor coordinate system 17 can be represented as vector F Acc, the vehicle force vector 21 in the measuring unit coordinate system 18 as vector F IMU , the projected vehicle force vector 22 for the occupant 2 on the driver's seat 3 as vector F X and the projected vehicle force vector 22 for the occupant 2 on the passenger seat 4 as vector F Y be referred to.

[0048] Fig. 3 shows method steps of a method for determining the mass of the occupant 2 of the vehicle 1. The method can, for example, be carried out for the two occupants 2 of the vehicle 1 from Fig. 1 and Fig. 2 can be applied. In a method step S1, it can be provided that, by means of the occupant presence detection device 14, presence information 23 is determined which describes a presence of the occupant 2 at a location assigned to the occupant acceleration detection device 10, such as a location of the front passenger seat 4 or the driver's seat 3. It can then be checked in a method step S2 whether an occupant 2 is actually present in the vehicle 1 according to the determined presence information 23. If this is the case, method steps S3 and S4 can take place. If, for example, no occupant 2 is arranged in the vehicle 1, i.e., the check is unsuccessful, method step S1 can be carried out again, for example until the presence of the occupant 2 is detected.

[0049] In method step S3, a vehicle acceleration vector 24 is determined by means of the vehicle acceleration detection device 7. The vehicle acceleration vector 24 describes an acceleration experienced by the vehicle 1. A correction algorithm 25 can be applied to the vehicle acceleration vector 24 in order to at least reduce the effect of vibration and / or movement shocks of the vehicle 1 on the vehicle acceleration vector 24.

[0050] In method step S4, an occupant acceleration vector 26, which describes an acceleration experienced by the occupant 2, is determined by means of the occupant acceleration detection device 10. The occupant acceleration detection device 10 is different from the vehicle acceleration detection device 7.

[0051] Method step S4 can be preceded, for example, by method step S5 if the occupant acceleration detection device 10 is embodied as the radar sensor 11. A point cloud 27 characteristic of the occupant 2 is then acquired by means of the radar sensor 11, i.e., a collection of measurement data from the radar sensor 11 is determined. The acquired point cloud 27 is then evaluated to determine the occupant acceleration vector 26. For this purpose, in method step S6, speed change information 28 is determined, which describes a speed change between at least two point clouds 27 acquired one after the other. The occupant acceleration vector 26 is determined from the determined speed change information 28. Thus, the acceleration of the occupant 2 is inferred based on the observed speed change over time.

[0052] Alternatively or in addition to method steps S5 and S6, method steps S7 and S8 can be carried out. In method step S7, camera data 29 is acquired by means of the camera 12, which data describe at least two images of the occupant 2 acquired one after the other. The occupant acceleration vector 26 can now be determined by evaluating the acquired camera data 29. For this purpose, occupant speed change information 30 is determined in method step S8, which describes a speed change of the occupant 2 between the at least two images acquired one after the other. The occupant acceleration vector 26 is determined from the determined occupant speed change information 30, with the acceleration again being inferred based on the temporal change in speed.

[0053] In method step S9, the vehicle force vector 21, which describes the force acting on the vehicle 1, is determined. This is done based on the determined vehicle acceleration vector 24. Furthermore, to determine the vehicle force vector 21, vehicle mass information 31, which describes a vehicle mass of the vehicle 1, is taken into account. The vehicle mass information 31 can be provided and / or detected by a mass detection device. Furthermore, the correction algorithm 25 can be taken into account in method step S9.

[0054] Method step S9 is performed by the evaluation device 13. It may further be provided that the evaluation steps S6 and S8 are performed by the evaluation device 13. It may further be provided that the determination of the vehicle acceleration vector 24 and the occupant acceleration vector 26 in method steps S3 and S4, respectively, also takes place at least with the involvement of the evaluation device 13, wherein data from the vehicle acceleration detection device 7 and / or the occupant acceleration detection device 10 are provided to the evaluation device 13 for this purpose, which data are then evaluated accordingly by the evaluation device 13.

[0055] In a method step S10, the evaluation device 13 projects the determined vehicle force vector 21 onto the occupant 2, thereby calculating the projected vehicle force vector 22, which can alternatively be referred to as the occupant force vector. The location onto which the vehicle force vector 21 is projected can be predetermined, for example, based on the presence information 23, which for this purpose can have location information 32 that describes the location to which the occupant presence detection device 14 is assigned. Alternatively or additionally, the location onto which the vehicle force vector 21 is projected can be a location of a torso center of mass 33. The torso center of mass 33 is a center of mass of a torso of the occupant 2 and can be determined based on the data from the radar sensor 11.Alternatively or additionally, a body mass center of gravity 35 can be considered, which is determined from the torso mass center of gravity 33 and a head mass center of gravity 34, which describes the center of gravity 20 of the head of the occupant 2. The body mass center of gravity 35 is, for example, a more precise center of gravity 20 of the occupant 2 than the torso mass center of gravity 33 alone.

[0056] In a method step S11, mass information 36, which describes the mass of the occupant 2, is determined by means of the evaluation device 13. The mass information 36 is determined from the projected vehicle force vector 22 and the determined occupant acceleration vector 26. The mass information 36 determined here is typically merely an estimated mass of the occupant 2. This means that, depending on the value range, a distinction can be made, for example, between a toddler who weighs less than 10 kilograms, a child who weighs between more than 10 kilograms and less than 50 kilograms, and an adult who weighs more than 50 kilograms. The estimated mass can be evaluated, for example, for an airbag control system of an airbag of the vehicle 1 and / or for a warning device that warns about occupants 2 left behind in the vehicle 1, in particular if they are a child or toddler.The corresponding warning can, for example, be displayed in an application on a mobile device of a user of vehicle 1.

[0057] Fig. 4 and Fig. 5 show from two different perspectives the individual centers of mass 20 of the two occupants 2 on the driver’s seat 3 and the passenger seat 4. In Fig. 4 the head mass center 34 can be seen. Fig. 5, on the other hand, shows both the head mass center 34 and the respective torso mass center 33 of the respective occupant 2. In both Fig. 4 and Fig. 5 shows a direction of travel 37 of the vehicle 1 and various individual sub-areas 38 in the detection range of the radar sensor 11, which are sketched here as a grid.

[0058] The torso center of mass 33 can be determined as follows: The sub-area 38 of the acquired point cloud 27 is determined by determining that the acquired point cloud 27 has the highest signal-to-noise ratio compared to the remaining point cloud 27. The determined sub-area 38 is then assumed to be the torso center of mass 33 of the torso of the occupant 2. The vehicle force vector 21 can be projected onto the location of the assumed torso center of mass 33. Additionally or alternatively, it is possible to determine a further sub-area 38 of the acquired point cloud 27 by determining that the acquired point cloud 27 has the second-highest signal-to-noise ratio compared to the remaining point cloud 27. The further determined sub-area 38 is assumed to be the head center of mass 34 of the head of the occupant 2.If the location of the assumed torso center of mass 33 and the location of the assumed head center of mass 34 are now taken into account, the body of the occupant 2 can be modeled. In this model, a body center of mass 35 of the modeled body can be determined, which is then considered as the location to which the vehicle force vector 21 is projected.

[0059] Overall, the examples show a mass estimation for vehicle interior passengers, i.e., the occupants 2, based on the acceleration sensor 8 and / or the inertial measuring unit 9. For this purpose, the device 6 has the acceleration sensor 8 and / or the inertial measuring unit 9, i.e., an inertial sensor, on the vehicle 1, which in each case determines an acceleration vector of the vehicle 1, i.e., the vehicle acceleration vector 24. The device 6 further has at least the radar-based detection device for detecting occupants 2 in the vehicle interior, i.e., at least the radar sensor 11 as the occupant acceleration detection device 10. This provides a point cloud for each detected occupant 2, from which the acceleration of the respective occupant 2 can be estimated.By projecting the determined acceleration vector of vehicle 1 onto occupant 2, which is contained in vehicle force vector 21, it is possible, for example, to determine the mass of the respective occupant 2. Thus, the mass information 36 of the individual occupant 2 can be estimated without additional hardware and / or without additional supplementation of existing functions. This ultimately allows for comfort settings, such as the automatic adjustment of a seat to support occupant 2, particularly when cornering, to prevent excessive body swinging. Furthermore, other applications are conceivable, such as the individual deployment of an airbag based on the expected mass and / or, if applicable, the size.

Claims

[1] Device (6) for determining a mass of an occupant (2) of a vehicle (1), the device (6) comprising: - a vehicle acceleration detection device (7) which is designed to determine a vehicle acceleration vector (24) which describes an acceleration experienced by the vehicle (1); - an occupant acceleration detection device (10) which is designed to determine an occupant acceleration vector (26) which describes an acceleration experienced by the occupant (2); and - an evaluation device (13) which is designed to determine a vehicle force vector (21) describing a force acting on the vehicle (1) on the basis of the determined vehicle acceleration vector (24), to project the vehicle force vector (21) onto the occupant (2) and to determine mass information (36) describing a mass of the occupant (2) from the projected vehicle force vector (22) and the determined occupant acceleration vector (26). [2] Device (6) according to claim 1, characterized by that the occupant acceleration detection device (10) is designed as a radar sensor (11) and / or camera (12). [3] Device (6) according to one of the preceding claims, characterized by that the vehicle acceleration detection device (7) is designed as an acceleration sensor (8) and / or inertial measuring unit (9). [4] Device (6) according to one of the preceding claims, characterized byin that the device (6) has an occupant presence detection device (14), in particular a pressure sensor (15) and / or a seat belt buckle sensor (16), which is designed to detect presence information (23) describing a presence of the occupant (2) at a location assigned to the occupant presence detection device (14) and to provide it to the evaluation device (13). [5] Method for determining a mass of an occupant (2) of a vehicle (1), the method comprising the following steps: - determining (S3) a vehicle acceleration vector (24) which describes an acceleration experienced by the vehicle (1) by means of a vehicle acceleration detection device (7); - determining (S4) an occupant acceleration vector (26) which describes an acceleration experienced by the occupant (2) by means of an occupant acceleration detection device (10); - by means of an evaluation device (13): - determining (S9) a vehicle force vector (21) which describes a force acting on the vehicle (1) based on the determined vehicle acceleration vector (24); - projecting (S10) the determined vehicle force vector (21) onto the occupant (2); and - Determining (S11) mass information (36) describing a mass of the occupant (2) from the projected vehicle force vector (22) and the determined occupant acceleration vector (26). [6] Method according to claim 5, characterized by in that the occupant acceleration detection device (10) is designed as a radar sensor (11), by means of which a point cloud (27) characteristic of the occupant (2) is detected (S5), the occupant acceleration vector (26) being determined by evaluating the detected point cloud (27). [7] Method according to claim 6, characterized bythat the characteristic point cloud (27) is continuously recorded, speed change information (28) which describes a speed change between at least two point clouds (27) recorded one after the other in time is determined (S6), and the occupant acceleration vector (26) is determined from the determined speed change information (28). [8] Method according to one of claims 6 or 7, characterized by that a partial area (38) of the recorded point cloud (27) in which the recorded point cloud (27) has a highest signal-to-noise ratio compared to the remaining point cloud (27) is determined, the determined partial area (38) is assumed to be the torso mass center of gravity (33) of a torso of the occupant (2), and the vehicle force vector (21) is projected onto a location of the assumed torso mass center of gravity (33). [9] Method according to claim 8, characterized bythat a further sub-area (38) of the recorded point cloud (27) in which the recorded point cloud (27) has a second-highest signal-to-noise ratio compared to the remaining point cloud (27) is determined, the determined further sub-area (38) is assumed to be the head mass center of gravity (34) of a head of the occupant (2), a body of the occupant (2) is modeled taking into account the locations of the assumed torso mass center of gravity (33) and the assumed head mass center of gravity (34), a body mass center of gravity (35) of the modeled body is determined and the vehicle force vector (21) is projected onto the location of the determined body mass center of gravity (35). [10] Method according to one of claims 5 to 9, characterized byin that the occupant acceleration detection device (10) is designed as a camera (12), by means of which camera data (29) are detected (S7), which describe at least two images of the occupant (2) detected one after the other in time, and the occupant acceleration vector (26) is determined by evaluating the detected camera data (29). [11] Method according to claim 10, characterized by that when evaluating the camera data (29), occupant speed change information (30) describing a speed change of the occupant (2) between the at least two images acquired one after the other in time is determined, and the occupant acceleration vector (26) is determined from the determined occupant speed change information (30) (S8). [12] Method according to one of claims 5 to 11, characterized bythat when determining the vehicle force vector (21), vehicle mass information (31) describing a vehicle mass of the vehicle (1) is taken into account, wherein the vehicle mass information (31) is provided and / or detected by means of a mass detection device. [13] Method according to one of claims 5 to 12, characterized by that a correction algorithm (25) is applied to the vehicle acceleration vector (24) and / or the vehicle force vector (21), whereby an effect of vibrations and / or movement shocks on the vehicle acceleration vector (24) and / or vehicle force vector (21) is at least reduced. [14] Method according to one of claims 5 to 13, characterized byin that the device (6) has an occupant presence detection device (14), in particular a pressure sensor (15) and / or a seat belt buckle sensor (16), by means of which presence information (23) describing a presence of the occupant (2) at a location assigned to the occupant presence detection device (14) is detected (S1), wherein the mass information (36) is determined only if the occupant (2) is present according to the detected presence information (23) (S2). [15] Method according to claim 14, characterized by that when projecting the vehicle force vector (21) onto the occupant (2), the detected presence information (23) is taken into account, wherein the presence information (23) in particular comprises location information (32) which describes the location assigned to the occupant presence detection device (14).

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