Method and device for contactless provision of function in motor vehicle

Abstract

The invention relates to a method for contactlessly providing a function in a motor vehicle, comprising the following steps: a) detecting (S2) an approach of a person towards the motor vehicle; b) recognizing (S4) a gesture of the person; and c) providing (S5) a function dependent on the identification according to steps a) and b); wherein ultrasonic signals are transmitted and received in steps a) and b) for identification, and wherein: (i) the signal repetition rate of the ultrasonic signals transmitted in step b) is higher than that of step a); and / or (ii) the repetition rate of receiving the ultrasonic signal in step b) is higher than that in step a).

Description

Field of the Invention

[0001] The present invention relates to a method and a device for contactlessly providing functions in a motor vehicle, in particular for contactlessly opening a door, in particular a rear hatch of a motor vehicle. The present invention also relates to a computer program product. Background Art

[0002] Various methods and devices are used to contactlessly open the rear hatch of a motor vehicle. For example, methods in which a posture (e.g., foot movement, stepping in the direction of the bumper) is detected and thus the opening of the rear hatch is triggered are conventional. For this purpose, systems with capacitive sensors known from, for example, DE 10 2009 025 212 A1, or systems with radar-based sensors known from, for example, DE10 2016 220 084 A1 are typically used to detect foot movement.

[0003] A method is known from WO 2021 / 037052 A1, in which, in a first step, it is detected by means of an ultrasonic sensor whether a person is located within a predetermined distance from the vehicle. If this is the case, an image is projected onto the ground, and the reaction of the person to the image is recognized by means of a camera. If the reaction corresponds to a predefined posture, the opening of the rear hatch is triggered.

[0004] Such sensors are specifically for opening doors.

[0005] A method is known from US 2017 / 009509 A1, in which initially a proximity detection is performed. The proximity detection is performed by means of a smart key. In a second step, a posture is recognized. This can be done using a camera or by means of infrared or ultrasonic signals. Summary of the Invention

[0006] Against this background, it is an object of the present invention to provide an improved method and device for contactlessly providing functions in a motor vehicle, in particular for contactlessly opening a door, in particular a rear hatch of a motor vehicle.

[0007] Therefore, a method for contactlessly providing a function in a motor vehicle is proposed, wherein the method comprises the following steps: a) recognizing the approach of a person to the motor vehicle; b) recognizing the posture of the person; and c) providing a function depending on the recognition according to steps a) and b); wherein ultrasonic signals for recognition are transmitted and received in each of steps a) and b), which particularly comprise pulses or pulse sequences, and wherein: (i) compared to step a), the signal repetition rate of the ultrasonic signals transmitted in step b), in particular the repetition rate of the pulses or pulse sequences, is increased; and / or (ii) compared to step a), the repetition rate of receiving ultrasonic signals in step b) is increased.

[0008] In order to maintain low power consumption when the vehicle is turned off and still achieve reliable pose recognition, compared with step a), the signal repetition rate of the ultrasonic signal transmitted in step b), in particular the repetition rate of the pulse or pulse sequence, is increased, and / or compared with step a), the repetition rate of receiving the ultrasonic signal in step b), i.e., the repetition rate of the listening interval, is increased.

[0009] It is possible to identify the approach of an object to an ultrasonic sensor by measuring the time of flight of an ultrasonic signal using known methods. The ultrasonic sensor has an ultrasonic transmitter and an ultrasonic receiver. The data of the ultrasonic sensor can be evaluated at various levels, for example, using an ASIC, a central control unit, or an independent control unit. By using two ultrasonic sensors with overlapping measurement areas, the position of the object can be determined by known triangulation or trilateration methods. Then, the direction of motion is generated by the change of the position over time. If the measurement areas of multiple sensors overlap, position and direction determination can be performed by trilateration. Step a) can be performed by determining the approach of a person to a door by measuring the time of flight with the aid of two sensors. Objects other than a person can also approach and do not have to be distinguished from a person in step a).

[0010] The ultrasonic sensor emits ultrasonic signals at a frequency or pitch, for example, from 40 kHz to 60 kHz, and a signal repetition rate at which the ultrasonic signal repeats. Pulses or pulse sequences can be modulated onto this frequency or pitch as a carrier. For example, square wave pulses with a pulse duration of 20 ms can be emitted. Multiple pulses can also be continuously emitted as a pulse sequence. In addition, the pitch of the ultrasonic signal, i.e., the carrier frequency, can also be changed in the pulse or pulse sequence. For ultrasonic measurement, the pulses or pulse sequences are emitted at regular intervals at a repetition rate and a period, and the ultrasonic signal is received at a repetition rate. Depending on the required time resolution, the ultrasonic sensor can emit and / or receive ultrasonic signals at a higher or lower repetition rate. In this case, the repetition rate is not the carrier frequency of the ultrasonic signal, but the reciprocal of the interval period of the ultrasonic signal, in particular the pulse or pulse sequence, and / or the repetition rate during reception.

[0011] Between these ultrasonic signals, especially between pulses or pulse sequences, the ultrasonic sensor does not emit ultrasonic signals and / or does not receive ultrasonic signals, so that the ultrasonic sensor consumes as little power as possible. The proposed method for providing functions contactlessly in a motor vehicle, in particular for opening the door of a motor vehicle contactlessly, will often be used in a vehicle that is switched off. In order to maintain low power consumption in a switched-off vehicle, the ultrasonic sensor operates and / or receives at a low signal repetition rate, in particular a repetition rate of pulses or pulse sequences, in step a). In this case, the ultrasonic sensor can emit and / or receive ultrasonic signals or pulses or pulse sequences within less than 10% of the period T or less than 5% of the period T, and does not emit and / or receive ultrasonic signals or pulses or pulse sequences during the remaining time of the period.

[0012] In order to recognize a gesture, especially an opening gesture, in step b), the signal repetition rate, in particular the repetition rate of pulses or pulse sequences, and / or the reception repetition rate are increased, so as to provide the time resolution required for recognizing such a gesture. A state machine or a recurrent neural network can be used for gesture recognition.

[0013] According to one embodiment, the signal repetition rate according to (i) and / or (ii) in step a) is between 0.5 Hz and 5 Hz, especially between 1 Hz and 3 Hz.

[0014] According to one embodiment, the repetition rate according to (i) and / or (ii) in step b) is between 10 Hz and 50 Hz, especially between 20 Hz and 30 Hz.

[0015] According to one embodiment, the motor vehicle has at least one ultrasonic sensor configured for parking assistance, wherein ultrasonic signals are emitted and / or received by means of the at least one ultrasonic sensor in step a) and / or b).

[0016] Most modern vehicles already have ultrasonic sensors for parking assistance. If these sensors can be used to provide functions contactlessly, especially for opening the trunk, the sensors will not incur additional costs. For example, vehicles usually have three to six ultrasonic sensors in the rear area for parking assistance.

[0017] According to one embodiment, in step a) and / or b), exactly two or at least two ultrasonic sensors are used to emit and / or receive ultrasonic signals.

[0018] Two ultrasonic sensors with overlapping detection areas allow determining the direction of an object in addition to the distance. If it is restricted to two active ultrasonic sensors, the energy consumption can be minimized and the function of proximity detection or recognition of an opening gesture can be retained.

[0019] According to one embodiment, only one ultrasonic sensor is used for step b).

[0020] If the posture, especially the opening posture, is appropriately selected, the recognition of the posture can be related to only one ultrasonic sensor with the least possible energy consumption.

[0021] According to one embodiment, at least two ultrasonic sensors alternately emit ultrasonic signals.

[0022] To further reduce the energy consumption of the two ultrasonic sensors, two sensors with overlapping measurement areas can alternately emit signals. However, it is also possible to expand the detection area for recognizing the approach of a person in step a), because more than two ultrasonic sensors are used and still maintain low energy consumption because these ultrasonic sensors alternately emit signals.

[0023] According to one embodiment, in step a), a hypothesis about the movement of the person is formed, and if the hypothesis predicts the approach of the person in a defined area with a probability higher than a predetermined probability, step b) is initiated.

[0024] This hypothesis formation can be implemented, for example, using an object tracking method based on multiple measurement hypotheses known from WO 2020 / 007487 A1. For this purpose, various multi-object tracking methods are possible, in which, in particular, by means of a random finite set filter, in a specific embodiment as a so-called probability hypothesis density filter, cardinality probability hypothesis density filter, multi-Bernoulli filter, such as a cardinality-balanced multi-Bernoulli filter, generalized labeled multi-Bernoulli filter, labeled multi-Bernoulli filter, Poisson multi-Bernoulli mixture filter, Poisson multi-Bernoulli filter or an approximation filter thereof, a hypothesis about the object movement is formed, and if the hypothesis predicts the approach of the person with a probability higher than a predetermined probability, step b) is executed. Since a high probability has already been generated in step a), that is, the person deliberately moves towards the door and may also want to open the door, and then this is confirmed in steps b) and c), this hypothesis formation can achieve a high recognition rate of the door opening intention and a low number of false door openings.

[0025] The proposed method for opening the door of a motor vehicle without contact implements various postures. The known movement of the foot in the direction of the motor vehicle bumper is possible, as well as forward and lateral movements. For example, if at least two ultrasonic sensors are used in step b), it is possible to distinguish between forward and backward stepping movements or lateral and backward stepping movements. Of course, further movement patterns and postures are also possible, such as the movement of the arm and / or hand.

[0026] According to one embodiment, when the smart key associated with the motor vehicle communicates with the motor vehicle and the motor vehicle is in the parking position or simultaneously, step a) is executed.

[0027] For example, during driving, opening the vehicle door is prohibited. Additionally, during driving, the ultrasonic sensors of the motor vehicle may be required for other functions, such as parking assistance or parking space search. Therefore, if the proposed method for providing functions contactlessly in a motor vehicle, especially for opening the door contactlessly, is used only in a motor vehicle in a parked position, it is advantageous for an embodiment of the present invention. The parked position can be determined, for example, by the setting P of the automatic transmission, a fixed parking brake, a vehicle with the engine off and a gear engaged, all of which are additionally combined with detecting the stillness of the wheels by means of wheel speed sensors. Additionally, an unauthorized person cannot open the door of the motor vehicle intentionally or unintentionally. If the smart key communicates with the vehicle's control unit, the risk of being opened by an unauthorized person can be reduced. In this case, the smart key includes multiple vehicle access controls, such as a radio key, an RFID card, and an RFID transponder in the key, and also includes a mobile wireless device that can be used as a motor vehicle key. If there is authorization to open the door due to such a smart key, step a) begins with detecting the person's approach to the door. In this case, the proposed method in an embodiment can allow the smart key to be inside or outside the vehicle, or can also only allow the smart key to be outside the vehicle in order to trigger step a). For example, in the first case, a front passenger without a smart key can also open the door, such as the luggage compartment door, while the driver is in the vehicle with their smart key.

[0028] A maximum time can be defined for each of steps a) and b), after which, if no approach or opening gesture occurs, the sequence returns to the previous step or the proposed method terminates. Then, the restart of the proposed method can be triggered, for example, by a closing process.

[0029] According to one embodiment, it is recognized that the person remains standing in the target area between steps a) and b).

[0030] After detecting the person's approach to the door in step a), before performing step b), it is recognized in a further step whether the person remains standing in the target area. For example, the target area can be an area that is 0.5 to 1 meter away from the door and approximately 1 meter wide. If the person remains standing in the target area, that is, the ultrasonic sensor recognizes that the object in the target area has moved within the target area for a minimum time, such as 0.5 seconds, and less than a maximum distance, such as 0.1 m, then step b) is started.

[0031] According to one embodiment, in order to recognize maintaining a standing position, another ultrasonic signal is transmitted and received, which particularly includes a pulse or a pulse sequence, and wherein (i) the signal repetition rate of the another ultrasonic signal transmitted, particularly the repetition rate of the pulse or the pulse sequence, is increased compared to the signal repetition rate of the ultrasonic signal transmitted in step a), particularly the repetition rate of the pulse or the pulse sequence; and / or (ii) the repetition rate during receiving the another ultrasonic signal is increased compared to the repetition rate of receiving the ultrasonic signal according to step a).

[0032] According to one embodiment, the function according to step c) includes opening the driver's door, the front passenger door, the front door, the rear door, the luggage compartment door or the rear hatch, the front compartment door or the front hatch, or the door for power connection or the door for fuel filling opening without contact, and / or the posture according to step b) is an opening posture.

[0033] According to one embodiment, the function according to step c) includes folding the rearview mirror or deploying the trailer hitch without contact.

[0034] The proposed method is preferably used to open the luggage compartment door or the rear hatch. However, the proposed method for opening the doors of a motor vehicle without contact can also be used to open the driver's door, the front passenger door, the front door, the rear door, the front compartment door or the front hatch, or the door for power connection or the door for fuel filling opening.

[0035] "Front compartment" represents "front luggage compartment", referring to the storage compartment at the front of the vehicle, especially in an electric vehicle.

[0036] Furthermore, a device for providing functions without contact in a motor vehicle is proposed, including: a first recognition unit for recognizing the approach of a person to the motor vehicle; a second recognition unit for recognizing the posture of the person; and a providing unit for providing a function depending on the recognition by means of the first and second recognition units. The first and second recognition units are configured to transmit and receive corresponding ultrasonic signals, which particularly include a pulse or a pulse sequence. The signal repetition rate of the ultrasonic signal transmitted in the second recognition unit, particularly the repetition rate of the pulse or the pulse sequence, is increased compared to the first recognition unit; and / or the repetition rate of receiving the ultrasonic signal in the second recognition unit is increased compared to the first recognition unit.

[0037] The units described in the current context, such as the first and / or second recognition unit or the providing unit, can be implemented by hardware and / or software. For example, these units can be implemented on a microprocessor together with an associated storage device. The microprocessor including the storage device can be formed on, for example, the central controller of a motor vehicle.

[0038] According to one embodiment, a motor vehicle includes a device for providing functions without contact.

[0039] In one embodiment, a motor vehicle includes a motor vehicle controller, at least one ultrasonic sensor, and at least one actuator for opening a door.

[0040] There is also provided a computer program product including commands which, when executed by a computer, cause the computer to perform the above method.

[0041] The computer program product can be provided or supplied, for example, as a computer program device, on a storage medium such as a memory card, a USB stick, a CD-ROM, a DVD, or in the form of a file downloadable from a server in a network. This can be done, for example, in a wireless communication network by transmitting a corresponding file containing the computer program product or the computer program device.

[0042] In one embodiment, the computer program product is stored in the memory of the motor vehicle controller and includes commands which, when executed by the computer of the motor vehicle controller, cause the latter to perform the proposed method. In this case, the computer program product can be divided into modules which are stored in and executed in various computers or controllers. For example, a pre-evaluation of the data of the ultrasonic sensor can be carried out in an ASIC assigned to the ultrasonic sensor, for example, interference suppression can be carried out therein. Then, the pre-evaluated data is passed to another module for processing, and this other module, for example, detects whether a person is moving in the measurement area of the ultrasonic sensor and in which direction. A second module can check whether a person remains standing in a target area within a predefined time span. A third module can identify whether an opening gesture is performed by a person.

[0043] The embodiments and features described for the proposed device apply correspondingly to the proposed method, and vice versa, and the features of the method also apply to the device.

[0044] Other possible embodiments of the present invention also include combinations of features or embodiments not explicitly mentioned above or below with respect to the exemplary embodiments. In this case, those skilled in the art will also add individual aspects as improvements or additions to the corresponding basic forms of the present invention.

[0045] Further advantageous designs and aspects of the present invention form the subject matter of the dependent claims and the exemplary embodiments of the present invention described below. The present invention will be explained in more detail below with reference to the drawings based on preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of a motor vehicle with a person approaching is shown;

[0047] Figure 2 A flowchart of a method for contactlessly opening a door of a motor vehicle according to an exemplary embodiment is shown;

[0048] Figure 3 Schematically shows four examples of pulses or pulse sequences that can be emitted by an ultrasonic sensor; and

[0049] Figure 4 Schematically shows a device for performing a method for non - contact opening of a door of a motor vehicle according to an exemplary embodiment.

[0050] Unless otherwise specified, identical or functionally identical elements in the figures are denoted by the same reference numerals. Detailed description of the specific implementation

[0051] Figure 1 A schematic view of a motor vehicle 100 that a person 120 is approaching is shown from a bird's - eye perspective. The rear hatch closes the luggage compartment of the motor vehicle 100 as a luggage compartment door 110. The motor vehicle 100 is equipped with six ultrasonic sensors 131 to 136 of a parking assistance system in the rear area. The respective measurement directions of the ultrasonic sensors 131 to 136 are schematically shown by dashed lines, where the boundaries do not represent the maximum detection range. The ultrasonic sensors 131 to 136 each have an ultrasonic transmitter and an ultrasonic receiver, in particular. For example, it can be stipulated that the ultrasonic sensors 131 to 136 alternately emit pulses or pulse sequences. The data of the ultrasonic sensors 131 to 136 are evaluated and transmitted at various levels. For example, with the aid of an ASIC, the area near the sensor is evaluated for the respective sensor. The data of the ultrasonic sensors 131 to 136 are then transmitted to a central controller or a stand - alone controller and evaluated there.

[0052] If the motor vehicle 100 is reversing, then all of the ultrasonic sensors 131 to 136 are thus activated and measurements are made at a repetition rate of pulses or pulse sequences, so that static and dynamic obstacles can be quickly identified and the driver can be warned of the obstacles. If the vehicle 100 moves to a parking position, for example by shifting into gear P and turning off the engine, then the ultrasonic sensors 131 to 136 are thus turned off.

[0053] Person 120 is now approaching motor vehicle 100. Person 120 is carrying a smart key 150 with them. This can be a so-called key fob (similar to a key fob door opener, usually including an RFID token) or a card with an RFID chip, or it can also be a mobile phone. Ultrasonic sensors 131 to 136 are activated by bringing the smart key 150 into the reception range of motor vehicle 100. These sensors emit pulses or pulse sequences at a repetition rate of only 2 Hz in order to recognize the approach to the luggage compartment door 110. The repetition rate is not the carrier frequency or tone of the ultrasonic signal, which is between 40 kHz and 50 kHz, but the frequency at which the pulses or pulse sequences are transmitted and received. The respective ultrasonic sensors do not emit pulses between these pulses and thus do not consume power. For a parking assistance system, a repetition rate with a half-second interval between ultrasonic signals is too low. However, in the case of parking, this low repetition rate advantageously reduces the energy consumption of ultrasonic sensors 131 to 136. A repetition rate of 2 Hz is sufficient to detect the movement of person 120.

[0054] Once person 120 enters the detection area of ultrasonic sensors 131 to 136, they can be recognized as an object. In Figure 1 Person 120 is located in the area of the measurement directions of ultrasonic sensors 131 and 132 and leaves the measurement direction of sensor 131 in the direction of the arrow and enters the measurement direction of sensor 133. The position of person 120 can be determined by trilateration. The approach of person 120 to door 110 is generated by the time series of the position.

[0055] If person 120 is not recognized as approaching in the direction of luggage compartment door 110, the method for opening the luggage compartment door 120 contactlessly ends after a predefined time span and can be restarted, for example, by a closing process of smart key 150 or by disconnecting and re-establishing the communication between smart key 150 and motor vehicle 100.

[0056] If it is recognized that person 120 is approaching the luggage compartment door 110, it is checked whether they are standing still in the target area 140. The target area 140 is an area that is 0.5 to 1 m away from the rear of the vehicle 100 and approximately 1 m wide. The target area 140 is detected by ultrasonic sensors 133 and 134, so that only these two sensors check whether person 120 is standing still in the target area 140. If person 120 is standing still in the target area 140 for a minimum time of, for example, 1 second and moves at most 0.1 m from this position, then for the recognition of an opening gesture, the repetition rate of the ultrasonic sensors 133 and 134 covering the target area is increased, for example, to 25 Hz. The increase in the repetition rate can also be performed during or before it is recognized whether person 120 is standing still in the target area 140. The increase in the repetition rate is related to both transmission and reception. If person 120 is not standing still in the target area 140, the method then continues after a predefined time, updating the recognition of the approach.

[0057] If a foot movement away from the target area 140 in the direction of the right tail light 160 is defined as an opening gesture, the ultrasonic sensor 134 can thus be sufficient to recognize this opening gesture. Since a single opening gesture does not determine whether the luggage compartment door 110 is opened, but rather the approach of person 120 is recognized in advance, the recognition of a single opening gesture can allow for more incorrect recognitions without increasing the occurrence of incorrect openings that occur in the overall method.

[0058] If the movement of person 120's feet away from the target area 140 in the direction of the right tail light 160 is recognized as an opening gesture from the data of the ultrasonic sensor 134, the controller then transmits a control command to the actuator 190 to open the luggage compartment door 110. In Figure 1 wherein the luggage compartment door 110 is embodied as a rear hatch and swings upward due to the spring force after the luggage compartment lock is released.

[0059] If an opening gesture of person 120 is not recognized, the method can then continue after a predefined time, checking for a standing still posture in the target area 140.

[0060] Figure 2 The flowchart shows a method for contactless opening of the luggage compartment door 110 of a motor vehicle 100 according to an exemplary embodiment.

[0061] In a first step S1, the method for contactless opening of the luggage compartment door 110 of the motor vehicle 100 is activated. Due to an incorrectly executed method, the luggage compartment door 110 will be prevented from opening during driving. In addition, unauthorized person 120 is prevented from opening the luggage compartment door 110. In addition, depending on the situation, the ultrasonic sensors 131 to 136 are required for other purposes, such as for parking assistance.

[0062] To activate the method for contactless opening of the luggage compartment door 110 of a motor vehicle 100, conditions that must be met for the method to be operational are defined. Thus, in step S1, it is checked whether the motor vehicle 100 is in a parked position. For this purpose, the wheel rotation sensors are evaluated and it is checked whether the automatic transmission is in setting P and whether the parking brake is applied. Additionally, it is checked whether the motor vehicle 100 is permitted to be opened. For this purpose, it is checked whether the smart key 150 associated with the motor vehicle 100 around the vehicle communicates with the control unit of the vehicle 100. It can be expected that only when the motor vehicle is not locked or ready to be opened will an authorized person 120 attempt to open the luggage compartment door 110. These conditions must be met at the start of the method for contactless opening of the luggage compartment door 110 of the motor vehicle 100 and must remain met during the method. For example, if the parking brake is released and the gear is engaged, the method ends.

[0063] If the conditions for the method for contactless opening of the luggage compartment door 110 of the motor vehicle 100 are met, then in step S2 it is identified whether a person 120 is approaching the luggage compartment door 110. For this purpose, the ultrasonic sensors 131 to 136 emit signals at a repetition rate of 2 Hz. Then it can be determined from the data of the ultrasonic sensors 131 to 136 whether the person 120 is approaching the luggage compartment door 110. In this case, by using all six ultrasonic sensors 131 to 136, a large area can be covered for identification of the approach.

[0064] Regarding whether the person 120 is approaching the luggage compartment door 110, an assumption about the movement of the person 120 is formed, for example, by a multi-target tracking method, in particular by a random finite set filter. If the predicted probability of approach according to the assumption is greater than a predefined probability, then in step S3 the ultrasonic sensors 133 and 134 are used to check whether the person 120 remains standing in the target area 140. In this case, the ultrasonic sensors 131, 132, 135 and 136 can be deactivated so that they do not consume power in step S3. To check whether the person 120 remains standing in the target area 140, the repetition rate of the pulses or pulse sequence is increased, thus giving better time resolution and, for example, it can be identified that the person remains standing for up to 0.5 seconds. This increased repetition rate is, for example, between 5 Hz and 10 Hz, preferably between 6 Hz and 9 Hz.

[0065] If a person 120 who is standing still has been recognized in S3, then for step S4, the repetition rate of the pulses or pulse sequences of the ultrasonic sensors 133 and 134 is further increased. The further increased repetition rate is, for example, between 10 Hz and 50 Hz, preferably between 20 Hz and 30 Hz. The ultrasonic sensors 131, 132, 135, and 136 can remain switched off. In S4, a predefined open posture is recognized. For example, it can be recognized from the data of the ultrasonic sensors 133 and 134 that the person 120 moves back and forth in the target area 140.

[0066] If a predefined open posture has been recognized in step S4, then in step S5, a control signal is transmitted to the actuator 190 to open the luggage compartment door 110. The actuator 190 can be, for example, an electric motor that unlocks and opens the luggage compartment door 120.

[0067] Figure 3 Four examples of ultrasonic signals in the form of pulses or pulse sequences that can be emitted by ultrasonic sensors are schematically shown. In Figure 3 a), a square wave pulse is modulated onto the carrier frequency of the ultrasonic wave, for example 50 kHz. In each case, the square wave pulse is emitted again after a period T. The repetition rate of the pulse or pulse sequence is the reciprocal of the period. In Figure 3 b), the emitted pulse has amplitude modulation and is also emitted at a repetition rate of 1 / T. In Figure 3 c), a pulse sequence emitted at a repetition rate of 1 / T is shown. In Figure 3 d), in addition to the amplitude of the pulse, the carrier frequency is also modulated, but the repetition rate 1 / T is the same as in the other examples. In all four examples, the signal component in the period is less than 50%, i.e., most of the time no signal is emitted. For the proposed method, it is advantageous if the signal component in the period is even smaller, so that the power consumption of the ultrasonic sensor is reduced, for example, below 90%. However, the repetition rate of the pulse or pulse sequence cannot be reduced arbitrarily, because otherwise it is possible to approach the motor vehicle between the signals without being recognized. The duration of the signal emission and reception by the ultrasonic sensor can be between 20 ms and 60 ms in the embodiment, especially between 30 ms and 50 ms.

[0068] Figure 4 A device for performing a method for opening the door 110 of a motor vehicle 100 contactlessly according to an exemplary embodiment is schematically shown.

[0069] Each of the four ultrasonic sensors 131 to 134 is provided with a sensor proximal ASIC 200 for preprocessing sensor data and transmitting the sensor data to the computer 170 via the data bus 210, where the computer 170 can be part of a motor vehicle controller. The ultrasonic sensors 131 to 134 measure their measurement areas at a repetition rate of 2 Hz in the form of pulses or pulse sequences. The first module 171 of the computer 170 (also referred to as the "first recognition unit" in this example) processes the sensor data to identify whether an object (such as the person 120) is moving in a direction corresponding to approaching the door 110. If such an approach is recognized, the second module 172 is then called, which identifies whether the person 120's standing still in the target area 140 is indicated by the sensor data. If such standing still of the person 120 is recognized, the second module 172 (also referred to as the "third recognition unit" in this example) generates a control signal that is transmitted via the data bus 210 to the sensor proximal ASIC, and this control signal turns off the ultrasonic sensors 131 and 134 and increases the repetition rate of the pulses or pulse sequences of the ultrasonic sensors 132 and 133. In addition, the third module 173 is called. The third module 173 (also the "second recognition unit" in this example) identifies from the sensor data of the ultrasonic sensors 132 and 133 whether the person 120 is performing a predefined opening gesture in the target area 140, such as taking a step to the left and backward. If the third module 173 recognizes the predefined opening gesture, the fourth module 174 generates a control command that is transmitted via the control line 180 to the actuator 190, which opens the door 110, and ends the method for opening the door 110 of the motor vehicle 100 without contact. The fourth module 174, the control line 180, and the actuator 190 are also jointly referred to as the "providing unit" in this example. The first, second, third, and fourth modules 171, 172, 173 can be specifically designed as an "embedded system", that is, a dedicated combination of hardware and software.

[0070] Although the present invention has been described based on exemplary embodiments, it can be modified in various ways.

[0071] List of reference numerals

[0072] 100 Motor vehicle

[0073] 110 Trunk door

[0074] 120 Person

[0075] 131 to 136 Ultrasonic sensors

[0076] 140 Target area

[0077] 150 Smart key

[0078] 160 Right taillight

[0079] 170 Computer

[0080] 171 First Module

[0081] 172 Second Module

[0082] 173 Third Module

[0083] 174 Fourth Module

[0084] 180 Control Line

[0085] 190 Actuator

[0086] 200 Sensor Proximal ASIC

[0087] 210 Data Bus

Claims

1. A method for contactless provision of functions in a motor vehicle (100), comprising the steps of: a) identifying (S2) the approach of a person (120) to the motor vehicle (100); b) identifying (S4) the posture of the person (120); and c) providing (S5) a function depending on the identification according to steps a) and b); wherein, in each case, ultrasonic signals are transmitted and received for the identification in steps a) and b), wherein: (i) compared to step a), the signal repetition rate of the ultrasonic signal transmitted in step b) is increased; and / or (ii) compared to step a), the repetition rate of receiving the ultrasonic signal in step b) is increased.

2. The method according to claim 1, wherein The repetition rate according to (i) and / or (ii) in step a) is between 0.5 Hz and 5 Hz, in particular between 1 Hz and 3 Hz.

3. The method according to claim 1 or 2, wherein The repetition rate according to (i) and / or (ii) in step b) is between 6 Hz and 20 Hz, in particular between 7 Hz and 13 Hz.

4. The method according to any one of the preceding claims, wherein, The motor vehicle (100) comprises at least one ultrasonic sensor (131 - 136) configured for parking assistance, wherein the ultrasonic signals in steps a) and / or b) are transmitted and / or received by means of the at least one ultrasonic sensor (131 - 136).

5. The method according to any one of the preceding claims, wherein, In step a) and / or b), exactly two or at least two ultrasonic sensors (131 - 136) are used to transmit and / or receive the ultrasonic signals.

6. The method according to any one of the preceding claims, wherein, At least two ultrasonic sensors (131 - 136) transmit ultrasonic signals alternately.

7. The method according to any one of the preceding claims, wherein In step a), a multi-target tracking method is used, in particular by means of a random finite set filter, in a specific embodiment as a so-called probability hypothesis density filter, cardinality probability hypothesis density filter, multi-Bernoulli filter, such as a cardinality balanced multi-Bernoulli filter, generalized labeled multi-Bernoulli filter, labeled multi-Bernoulli filter, Poisson multi-Bernoulli mixture filter, Poisson multi-Bernoulli filter or an approximation filter thereof, to form hypotheses about the movement of objects, and if the hypothesis predicts the approach of the person (120) with a probability higher than a predetermined probability, then step b) is executed.

8. The method according to any one of the preceding claims, wherein, The posture in step b) includes arm movements, foot movements in the direction of the bumper of the motor vehicle (100), forward and backward stepping movements, or lateral and backward stepping movements.

9. The method according to any one of the preceding claims, wherein, Step a) is executed when an intelligent key (150) associated with the motor vehicle (100) communicates with the motor vehicle (100) and the motor vehicle (100) is in a parking position or simultaneously.

10. The method according to any one of the preceding claims, wherein, It is identified that the person (120) remains standing (S3) in a target area (140) between steps a) and b).

11. The method according to claim 10, wherein, To identify the remaining standing (S3), another ultrasonic signal is transmitted and received, the another ultrasonic signal comprising a pulse or a pulse sequence, and wherein: (i) compared to the signal repetition rate of the ultrasonic signal transmitted in step a), the signal repetition rate of the transmitted another ultrasonic signal is increased; and / or (ii) The repetition rate of receiving another ultrasonic signal is increased compared to the repetition rate of receiving the ultrasonic signal according to step a).

12. The method according to any one of the preceding claims, wherein, The function according to step c) includes opening the driver's door, the front passenger door, the front door, the rear door, the luggage compartment door or the rear hatch, the front compartment door or the front hatch, or the door for power connection or the door for fuel filling opening without contact, and / or the posture according to step b) is an opening posture.

13. A device for providing a function without contact in a motor vehicle (100), comprising: a first identification unit (171) for identifying the approach of a person (120) to the motor vehicle (100); a second identification unit (173) for identifying the posture of the person (120); and a providing unit (174, 180, 190) for providing a function depending on the identification by means of the first identification unit and the second identification unit; wherein the first identification unit and the second identification unit are configured to transmit and receive respective ultrasonic signals, the ultrasonic signals comprising pulses or a pulse sequence, and wherein: (i) The frequency of the pulses or the pulse sequence of the ultrasonic signal transmitted in the second identification unit is increased compared to the first identification unit; and / or (ii) The frequency of sampling the ultrasonic signal when receiving the ultrasonic signal in the second identification unit is increased compared to the first identification unit.

14. A motor vehicle (100) having the device according to claim 13.

15. A computer program product comprising instructions which, when the program is executed by a computer (170), cause the computer to perform the method according to any one of claims 1 - 12.

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