Method and device for contactlessly providing a function in a motor vehicle

Abstract

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

Description

[0001] METHOD AND DEVICE FOR CONTACTLESS PROVISION

[0002] A FUNCTION IN A MOTOR VEHICLE

[0003] The present invention relates to a method and a device for contactlessly providing a function in a motor vehicle, in particular for contactlessly opening a door, in particular a tailgate, of a motor vehicle. The present invention further relates to a computer program product.

[0004] Various methods and devices are in use that allow a person to open the tailgate of a vehicle without contact. Common methods include detecting a gesture, such as a foot movement or a kick towards the bumper, which then triggers the opening of the tailgate. Systems with capacitive sensors, such as those used in

[0005] DE 10 2009 025 212 A1, or with radar-based sensors, such as from the

[0006] DE 10 2016 220 084 A1 known, used.

[0007] WO 2021 / 037052 A1 discloses a method in which, in a first step, ultrasonic sensors are used to detect whether a person is within a predetermined distance of the vehicle. If this is the case, an image is projected onto the ground, and a camera detects the person's reaction to the image. If the reaction corresponds to a predefined gesture, the tailgate opens.

[0008] Such sensors are used exclusively to open the door.

[0009] US 2017 / 009509 A1 discloses a method in which proximity detection is first performed. The proximity detection is performed using a smart key. In a second step, a gesture is recognized. This can be done using a camera or infrared or ultrasonic signals. Against this background, one object of the present invention is to provide an improved method and device for the contactless provision of a function in a motor vehicle, in particular for the contactless opening of a door, in particular a tailgate of a motor vehicle.

[0010] Accordingly, a method for the contactless provision of a function in a motor vehicle is proposed, the method comprising the following steps: a) detecting an approach of a person to the motor vehicle; b) detecting a gesture of the person; and c) providing the function depending on the detection according to steps a) and b); wherein for the detection in steps a) and b) an ultrasonic signal is emitted and received in each case, which signal in particular has pulses or pulse sequences, and wherein: (i) a signal repetition rate, in particular a repetition rate of the pulses or pulse sequences, of the emitted ultrasonic signal is increased in step b) compared to step a); and / or (ii) a repetition rate for receiving the ultrasonic signal in step b) is increased compared to step a).

[0011] In order to keep power consumption low when the vehicle is switched off and still achieve reliable gesture recognition, the signal repetition rate, in particular the repetition rate of the pulses or pulse sequences, of the transmitted ultrasonic signal in step b) should be increased compared to step a) and / or the repetition rate for receiving the ultrasonic signal, the repetition rate of the listening interval, should be increased in step b) compared to step a).

[0012] The detection of an object approaching an ultrasonic sensor is possible using known methods by measuring the time of flight of the ultrasonic signal. Ultrasonic sensors have an ultrasonic transmitter and a receiver. The data from an ultrasonic sensor can be evaluated at various levels, e.g. with ASICs, central or stand-alone control units. Using two ultrasonic sensors with overlapping measuring ranges, the positions of objects can be determined using the well-known methods of triangulation or trilateration. The direction of movement can then be determined from the time course of the positions. If the measuring ranges of several sensors overlap, position and direction can be determined using trilateration. Step a) can be achieved by determining the approach of a person to the door using time-of-flight measurements from two sensors.An object that is not a person can also approach and does not need to be distinguished from a person in step a).

[0013] Ultrasonic sensors emit ultrasonic signals with a frequency or pitch of, for example, 40 to 60 kHz and a signal repetition rate at which the ultrasonic signals repeat. Pulses or pulse sequences can be modulated onto this frequency or pitch, as a carrier. For example, a rectangular pulse with a pulse duration of 20 ms can be sent. Several pulses can also be sent one after the other as a pulse sequence. The pitch of the ultrasonic signal, i.e. the carrier frequency, can also be changed within a pulse or pulse sequence. For ultrasonic measurements, the pulses or pulse sequences are sent at regular intervals with a repetition rate and a period, and ultrasonic signals are received at a repetition rate. Depending on the required temporal resolution, ultrasonic sensors can transmit and / or receive ultrasonic signals with a higher or lower repetition rate.The repetition rate is not the carrier frequency of the ultrasonic signal, but the inverse of the period of the spacing of the ultrasonic signals, in particular the pulses or pulse sequences, and / or the repetition rate when receiving.

[0014] Between these ultrasonic signals, in particular pulses or pulse sequences, the ultrasonic sensor does not transmit and / or receive any ultrasonic signals so that the ultrasonic sensor consumes as little power as possible. The proposed method for the contactless provision of a function in a motor vehicle, in particular for the contactless opening of a motor vehicle door, is often used when the vehicle is switched off. In order to keep power consumption low when the vehicle is switched off, the ultrasonic sensors in step a) should operate and / or receive with a low signal repetition rate, in particular repetition rate of the pulses or pulse sequences. The ultrasonic sensors can transmit and / or receive ultrasonic signals or pulses or pulse sequences in less than 10% of the period T or in less than 5% of the period T and do not transmit or receive any ultrasonic signals or pulses in the remainder of the period.Pulses or pulse sequences and / or not received.

[0015] To recognize a gesture, in particular an opening gesture, in step b), the signal repetition rate, in particular the repetition rate of the pulses or pulse sequences, and / or the reception repetition rate is increased to provide the necessary temporal resolution to recognize such a gesture. State machines or recursive neural networks can be used to recognize the gesture.

[0016] According to one embodiment, the signal repetition rate according to (i) and / or (ii) in step a) is between 0.5 and 5 Hz, in particular between 1 and 3 Hz.

[0017] According to one embodiment, the repetition rate according to (i) and / or (ii) in step b) is between 10 and 50 Hz, in particular between 20 and 30 Hz.

[0018] According to one embodiment, the motor vehicle has at least one ultrasonic sensor which is designed to be used for a parking aid, wherein the ultrasonic signal in step a) and / or b) is transmitted and / or received by means of the at least one ultrasonic sensor.

[0019] Most modern vehicles already have ultrasonic sensors for parking assistance. If these sensors can be used to provide a contactless function, particularly opening the trunk, there are no additional costs for the sensors. Vehicles often have between three and six ultrasonic sensors in the rear area for parking assistance.

[0020] According to one embodiment, exactly two or at least two ultrasonic sensors are used for transmitting and / or receiving the ultrasonic signal in steps a) and / or b). Two ultrasonic sensors with overlapping detection ranges allow the determination of not only the distance but also the direction of an object. Limiting the use of two active ultrasonic sensors minimizes energy consumption and retains the functionality of proximity detection or opening gesture recognition.

[0021] According to one embodiment, only one ultrasonic sensor is used for step b).

[0022] If a gesture, especially an opening gesture, is chosen appropriately, the recognition of the gesture can be combined with the lowest possible energy consumption using only one ultrasonic sensor.

[0023] According to one embodiment, at least two ultrasonic sensors alternately transmit ultrasonic signals.

[0024] To further reduce the energy consumption of two ultrasonic sensors, two sensors with overlapping measurement ranges can transmit signals alternately. However, it is also possible to increase the detection range for detecting the person's approach in step a) by using more than two ultrasonic sensors while still keeping energy consumption low by having these ultrasonic sensors transmit signals alternately.

[0025] According to one embodiment, in step a) hypotheses are formed about the movement of a person and if a hypothesis predicts the approach of a person into a defined area with a probability above a predetermined probability, step b) is initiated.

[0026] Such a hypothesis formation can be achieved, for example, with the method known from WO 2020 / 007487 A1

[0027] Methods for object tracking are carried out based on multiple measurement hypotheses. A variety of multi-object tracking methods are possible for this purpose, in which hypotheses about the movement of an object are formed, particularly using random finite set filters, in particular implementations as so-called probability hypothesis density filters, cardinalized probability hypothesis density filters, multi-Bernoulli filters, such as cardinality balanced multi-Bernoulli filters, generalized labeled multi-Bernoulli filters, labeled multi-Bernoulli filters, Poisson multi-Bernoulli mixture filters, Poisson multi-Bernoulli filters, or their approximations. If a hypothesis predicts the approach of a person with a probability above a predetermined probability, step b) is carried out.Such hypothesis formation enables a high recognition rate of the opening request and a low number of incorrect openings, since already in step a) a high probability can be generated that a person is moving purposefully towards the door and therefore probably wants to open it, which is then confirmed in steps b) and c).

[0028] The proposed method for contactless opening of a motor vehicle door enables various gestures. The familiar foot movement toward a vehicle bumper is possible, as are forward and sideways movements. For example, when using at least two ultrasonic sensors in step b), a forward and backward stepping movement or a sideways and backward stepping movement can be distinguished. Other movement patterns and gestures are, of course, also possible, e.g., arm and / or hand movements.

[0029] According to one embodiment, step a) is carried out when or while a smart key belonging to the motor vehicle is in communication with the motor vehicle and the motor vehicle is in park position.

[0030] The opening of the vehicle door, e.g., while driving, should be prevented. In addition, the motor vehicle's ultrasonic sensors may be required for other functions while driving, such as parking assistance or parking space search. Therefore, it is advantageous for embodiments of the invention if the proposed method for contactless provision of a function in a motor vehicle, in particular for contactless opening of a door, is only used when the motor vehicle is in the parked position. The parked position can be determined, for example, by the P position of an automatic transmission, an applied parking brake, a switched-off vehicle with a gear engaged, all of which can also be additionally determined in conjunction with detection of a standstill of the wheels using wheel speed sensors. In addition, unauthorized persons should not be able to open the motor vehicle door, either intentionally or unintentionally.The risk of unauthorized opening can be reduced if a smart key is in communication with a vehicle control unit. Smart key here includes a variety of vehicle access controls, such as radio keys, RFID cards and RFID transponders in keys, but also mobile devices that can serve as keys for the motor vehicle. If such a smart key is authorized to open the door, step a) is started by detecting a person approaching the door. In some embodiments, the proposed method can allow the smart key to be inside or outside the vehicle, or only allow the smart key to be outside the vehicle to trigger step a). In the first case, for example, a passenger can also open a door, e.g. a trunk door, without the smart key while the driver is in the vehicle with their smart key.

[0031] Maximum times can be defined for steps a) and b) respectively. If the approach is not successful or no opening gesture is made, the system returns to the previous step or aborts the proposed procedure. A restart of the proposed procedure can then be triggered, for example, by a closing action.

[0032] According to one embodiment, a person stopping in a target area is detected between steps a) and b).

[0033] After the person's approach to a door has been detected in step a), a further step, before step b), determines whether the person remains stationary in the target area. The target area can, for example, be a zone 0.5 to 1 m from the door and approximately 1 m wide. If the person remains stationary in the target area, i.e., the ultrasonic sensors detect an object in the target area that moves within the target area for a minimum time, e.g., 0.5 s, but less than a maximum distance, e.g., 0.1 m, then step b) is initiated.

[0034] According to one embodiment, a further ultrasonic signal is transmitted and received to detect the stoppage, which signal in particular comprises pulses or pulse sequences, and wherein: (i) a signal repetition rate, in particular a repetition rate of the pulses or pulse sequences, of the transmitted further ultrasonic signal is increased compared to the signal repetition rate, in particular the repetition rate of the pulses or pulse sequences, of the transmitted ultrasonic signal in step a); and / or (ii) a repetition rate when receiving the further ultrasonic signal is increased compared to a repetition rate for receiving the ultrasonic signal according to step a).

[0035] According to one embodiment, the function according to step c) comprises the contactless opening of a driver's door, a passenger door, a front door, a rear door, a trunk door or tailgate, a front door or front flap, or a door for a power connection or for a fuel filler opening and / or the gesture according to step b) is an opening gesture.

[0036] According to one embodiment, the function according to step c) comprises a contactless folding of a mirror or a folding out of a trailer hitch.

[0037] The proposed method is preferably used for opening a trunk door or tailgate. However, the proposed method for contactless opening of a motor vehicle door can also be used to open a driver's door, a passenger door, a front door, a rear door, a front door or front flap, or a door for a power connection or a fuel filler opening. "Trunk" stands for "front trunk" and refers to the storage compartment at the front of the vehicle, especially in electric vehicles.

[0038] Furthermore, a device for the contactless provision of a function in a motor vehicle is proposed, comprising: a first detection unit for detecting the approach of a person to the motor vehicle; a second detection unit for detecting a gesture of the person; and a provision unit for providing the function depending on the detection using the first and second detection units. The first and second detection units are configured to transmit and receive a respective ultrasonic signal, which in particular comprises pulses or pulse sequences. A signal repetition rate, in particular a repetition rate of the pulses or pulse sequences, of the transmitted ultrasonic signal is increased in the second detection unit compared to the first detection unit and / or a repetition rate for receiving the ultrasonic signal is increased in the second detection unit compared to the first detection unit.

[0039] The units described here, for example, the first and / or second detection unit or provision unit, can be implemented using hardware and / or software. For example, the units can be implemented on a microprocessor including associated memory. The microprocessor including memory can be implemented, for example, on a central control unit of the motor vehicle.

[0040] According to one embodiment, a motor vehicle comprises the device for contactless provision of a function.

[0041] In one embodiment, a motor vehicle comprises a motor vehicle control unit, at least one ultrasonic sensor, and at least one actuator for opening a door. Furthermore, a computer program product is proposed, which comprises instructions that, when executed by a computer, cause the computer to execute the method described above.

[0042] A computer program product, such as a computer program means, can be provided or delivered, for example, as a storage medium, such as a memory card, USB stick, CD-ROM, DVD, or in the form of a downloadable file from a server in a network. This can be done, for example, in a wireless communications network by transmitting a corresponding file with the computer program product or the computer program means.

[0043] In one embodiment, a computer program product is stored in a memory of the motor vehicle control unit, comprising instructions which, when executed by a processing unit of the motor vehicle control unit, cause the proposed method to be carried out. The computer program product can be divided into modules which are stored and executed in different computers or control units. For example, a pre-evaluation of the data from the ultrasonic sensor can take place in ASICs assigned to the ultrasonic sensors, e.g. interference suppression can take place there. The pre-evaluated data is then forwarded for processing in a further module which, for example, detects whether and in which direction a person is moving within the measuring range of the ultrasonic sensors. A second module can check whether a person remains stationary in the target area for a predefined period of time.A third module can detect whether an opening gesture is made by the person.

[0044] The embodiments and features described for the proposed device apply accordingly to the proposed method, and conversely, the features of the method also apply to the device. Further possible implementations of the invention also include combinations of features or embodiments not explicitly mentioned above or below with regard to the exemplary embodiments. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0045] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below using preferred embodiments with reference to the accompanying figures.

[0046] Fig. 1 shows a schematic view of a motor vehicle being approached by a person;

[0047] Fig. 2 shows a flowchart for methods for contactless opening of a door of a motor vehicle according to an embodiment;

[0048] Fig. 3 shows schematically four examples of pulses or pulse sequences that can be sent by an ultrasonic sensor; and

[0049] Fig. 4 schematically shows a device for carrying out the method for contactless opening of a door of a motor vehicle according to an embodiment.

[0050] In the figures, identical or functionally equivalent elements have been given the same reference numerals unless otherwise stated.

[0051] Fig. 1 shows a schematic view of a motor vehicle 100 from a bird's eye view, which a person 120 is approaching. A tailgate closes the trunk of the motor vehicle 100 as a trunk 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 measuring direction of the ultrasonic sensors 131 to 136 is shown schematically in dotted lines, whereby the boundary does not represent the maximum detection range. The ultrasonic sensors 131 to 136 each have, in particular, an ultrasonic transmitter and a receiver. For example, it can be provided that the ultrasonic sensors 131 to 136 alternately emit pulses or pulse sequences. The data from the ultrasonic sensors 131 to 136 are evaluated and forwarded at different levels. For example, a sensor-related evaluation for the respective sensor takes place with the help of ASICs.The data from the ultrasonic sensors 131 to 136 are then sent to a central or stand-alone control unit and evaluated there.

[0052] When the motor vehicle 100 is reversing, all ultrasonic sensors 131 to 136 are active and measure with a pulse or pulse sequence repetition rate, allowing both static and dynamic obstacles to be quickly detected and the driver to be warned of them. If the vehicle 100 is placed in park, e.g., by engaging gear P and turning off the engine, the ultrasonic sensors 131 to 136 are deactivated.

[0053] A person 120 now approaches motor vehicle 100. Person 120 carries a smart key 150. This can be a so-called fob (key chain-like door opener, usually containing an RFID token) or a card with an RFID chip, or even a mobile phone. Bringing smart key 150 into the reception range of motor vehicle 100 activates ultrasonic sensors 131 to 136. These transmit pulses or pulse sequences with a repetition rate of only 2 Hz to detect an approach to trunk door 110. The repetition rate is not the carrier frequency or pitch of the ultrasonic signal, which lies between 40 and 50 kHz, but rather the frequency at which pulses or pulse sequences are transmitted and received. The respective ultrasonic sensor does not transmit pulses between these pulses to avoid power consumption.For a parking assistance system, this repetition rate, with a half-second interval between ultrasonic signals, would be too low. However, in the situation of a parked vehicle, this low repetition rate advantageously reduces the energy consumption of the ultrasonic sensors 131 to 136. The repetition rate of 2 Hz is sufficient to detect the movement of person 120.

[0054] As soon as person 120 enters the detection range of an ultrasonic sensor 131 to 136, they can be detected as an object. In Fig. 1, person 120 is located within the measurement direction of ultrasonic sensors 131 and 132 and moves in the direction of the arrow, out of the measurement direction of sensor 131 and into the measurement direction of sensor 133. The position of person 120 can be determined by trilateration. The time series of the positions determines the approach of person 120 to door 110.

[0055] If no approach of the person 120 in the direction of the trunk door 110 is detected, the method for contactless opening of the trunk door 120 is terminated after a predefined period of time and can be restarted, for example, by a closing process using the smart key 150 or by disconnecting and re-establishing the communication between the smart key 150 and the motor vehicle 100.

[0056] If it is detected that the person 120 is approaching the trunk door 110, a check is made to determine whether the person remains stationary in the target area 140. The target area 140 is a zone located 0.5 to 1 m from the rear of the vehicle 100 and approximately 1 m wide. The target area 140 is detected by the ultrasonic sensors 133 and 134, so that only these two sensors check whether the person 120 remains stationary in the target area 140. If the person 120 remains stationary in the target area 140 and moves away from the position for a minimum time, e.g., 1 s, or a maximum of 0.1 m, the repetition rate of the ultrasonic sensors 133 and 134 covering the target area is increased, for example, to 25 Hz, to detect an opening gesture. The increase in the repetition rate can also be made during or before detecting whether the person 120 remains stationary in the target area 140. The increase in the repetition rate affects both the transmission and the reception of the same.If the person 120 does not remain in the target area 140, the process continues after a predefined time with a renewed detection of the approach. If the opening gesture is defined as a foot movement from the target area 140 toward the right taillight 160, the ultrasonic sensor 134 may be sufficient to detect this opening gesture. Since the opening gesture alone does not determine whether the trunk door 110 is opened, but rather the approach of the person 120 has been detected beforehand, the detection of the opening gesture alone can allow for more false detections without resulting in an increased occurrence of incorrect openings in the overall process.

[0057] If the movement of the foot of the person 120 from the target area 140 in the direction of the right rear light 160 is recognized as an opening gesture from the data of the ultrasonic sensor 134, the control unit sends a control command to an actuator 190 to open the trunk door 110. In Fig. 1, the trunk door 110 is designed as a tailgate and then swings open due to spring force after the trunk lock is released.

[0058] If no opening gesture of the person 120 is detected, the process can be continued after a predefined time with the check of whether the person remains in the target area 140.

[0059] Fig. 2 shows a flowchart for a method for contactless opening of a trunk door 110 of a motor vehicle 100 according to an embodiment.

[0060] In a first step S1, the method for contactless opening of a trunk door 110 of a motor vehicle 100 is activated. The method should prevent the trunk door 110 from opening while driving due to an incorrectly performed method. Furthermore, the method should prevent an unauthorized person 120 from opening the trunk door 110. Furthermore, the ultrasonic sensors 131 to 136 are required for other purposes, e.g., for parking assistance, depending on the situation.

[0061] To activate the method for contactless opening of the trunk door 110 of the motor vehicle 100, conditions are therefore defined that must be met for the method to run. In step S1, a check is therefore made to determine whether the motor vehicle 100 is in the parked position. For this purpose, wheel rotation sensors are evaluated and a check is made to determine whether an automatic transmission is in the P position and the parking brake is applied. Furthermore, a check is made to determine whether the motor vehicle 100 should be able to be opened. For this purpose, a check is made to determine whether a smart key 150 belonging to the motor vehicle 100 is in or near the vehicle and is communicating with a control unit of the vehicle 100. Only if the motor vehicle is not locked or ready to be opened can it be expected that an authorized person 120 will attempt to open the trunk door 110.The conditions must be met to start the process for contactless opening of the trunk door 110 of the motor vehicle 100 and must remain met throughout the process. For example, if the parking brake is released and a gear is engaged, the process is terminated.

[0062] If the conditions for the method for contactless opening of the trunk door 110 of the motor vehicle 100 are met, it is detected in step S2 whether a person 120 is approaching the trunk door 110. For this purpose, the ultrasonic sensors 131 to 136 transmit signals at a repetition rate of 2 Hz. From the data of the ultrasonic sensors 131 to 136, it can then be determined whether a person 120 is approaching the trunk door 110.

[0063] By using all six ultrasonic sensors 131 to 136, a large area can be covered for detecting approach.

[0064] Whether or not a person 120 is approaching the trunk door 110 is formed, for example by means of a multi-object tracking method, in particular by means of a random finite set filter. If, according to the hypothesis, an approach is predicted with a probability greater than a predefined probability, a check is carried out in a step S3 using the ultrasonic sensors 133 and 134 to determine whether the person 120 remains stationary in the target area 140. The ultrasonic sensors 131, 132, 135 and 136 can be deactivated here so that they do not consume any power in step S3. The repetition rate of the pulses or pulse sequences is increased to check whether the person 120 remains stationary in the target area 140, so that a better temporal resolution is provided and, for example, a stoppage for 0.5 s can be detected. This increased repetition rate is, for example, between 5 and 10 Hz, preferably between 6 and 9 Hz.

[0065] If the person 120 has stopped moving has been detected in S3, the repetition rate of the pulses or pulse sequences of the ultrasonic sensors 133 and 134 is further increased for step S4. The further increased repetition rate is, for example, between 10 and 50 Hz, preferably between 20 and 30 Hz. The ultrasonic sensors 131, 132, 135, and 136 can remain switched off. In S4, a predefined opening gesture is detected. For example, it can be detected from the data of the ultrasonic sensors 133 and 134 that the person 120 is moving forward and backward in the target area 140.

[0066] If a predefined opening gesture is detected in step S4, a control signal is sent to an actuator 190 in step S5 to open the trunk door 110. The actuator 190 can, for example, be an electric motor that unlocks and opens a trunk door 120.

[0067] Fig. 3 schematically shows four examples of ultrasonic signals as pulses or pulse sequences that can be transmitted by an ultrasonic sensor. In Fig. 3 a), a rectangular pulse is modulated onto the carrier frequency of the ultrasound, e.g. 50 kHz. The rectangular pulse is re-transmitted after a period T. The repetition rate of the pulses or pulse sequences is the inverse of the period. In Fig. 3 b), the transmitted pulse has a modulation of the amplitude and is also transmitted at a repetition rate of 1 / T. Fig. 3 c) shows a pulse sequence that is transmitted at a repetition rate of 1 / T. In Fig. 3 d), in addition to the amplitude of the pulse, the carrier frequency is also modulated; however, the repetition rate 1 / T is the same as in the other examples. In all four examples, the signal component of the period is less than 50%, i.e. no signal is transmitted most of the time.For the proposed method, it is advantageous if the signal portion in the period is even lower, e.g., less than 90%, to reduce the power consumption of the ultrasonic sensor. However, the repetition rate of the pulses or pulse sequences cannot be reduced arbitrarily, as otherwise, it would be possible to approach the vehicle between the signals without being detected. The duration of the time period within which an ultrasonic sensor transmits and receives signals can, in embodiments, be between 20 and 60 ms, in particular between 30 and 50 ms.

[0068] Fig. 4 schematically shows a device for carrying out the method for contactless opening of a door 110 of a motor vehicle 100 according to an embodiment.

[0069] Four ultrasonic sensors 131 to 134 are each provided with a sensor-related ASIC 200 for preprocessing the sensor data and for transmitting the sensor data via a data bus 210 to a computer 170, where the computer 170 can be part of a motor vehicle control unit. The ultrasonic sensors 131 to 134 measure their measuring range with a pulse or pulse sequence repetition rate of 2 Hz. A first module 171 (here also referred to as the "first detection unit") of the computer 170 processes the sensor data to detect whether an object, e.g., a person 120, is moving in a direction that corresponds to an approach to a door 110. If such an approach is detected, a second module 172 is called, which detects whether the sensor data indicates that the person 120 has stopped in the target area 140.If such a stoppage of person 120 is detected, the second module 172 (which can also be referred to herein as the "third detection unit") generates control signals that are sent via the data bus 210 to the ASICs near the sensor. These signals deactivate ultrasonic sensors 131 and 134 and increase the repetition rate of the pulses or pulse sequences of ultrasonic sensors 132 and 133. A third module 173 is then called. The third module 173 (also referred to herein as the "second detection unit") detects from the sensor data of ultrasonic sensors 132 and 133 whether person 120 is performing a predefined opening gesture in the target area 140, e.g., taking a step to the left and back.If the third module 173 recognizes the predefined opening gesture, a fourth module 174 generates a control command, which is transmitted via a control line 180 to an actuator 190, which opens a door 110, and terminates the method for contactless opening of a door 110 of a motor vehicle 100. The fourth module 174, the control line 180, and the actuator 190 are collectively referred to herein as a "provisioning unit." The first, second, third, and fourth modules 171, 172, 173 can, in particular, be designed as an "embedded system," i.e., as an application-specific combination of hardware and software. Although the present invention has been described using exemplary embodiments, it is susceptible to modification in many ways.

[0070] LIST OF REFERENCE SYMBOLS

[0071] 100 motor vehicles

[0072] 110 trunk door

[0073] 120 people

[0074] 131 to 136 ultrasonic sensors

[0075] 140 target area

[0076] 150 Sm art-Key

[0077] 160 right taillight

[0078] 170 computers

[0079] 171 first module

[0080] 172 second module

[0081] 173 third module

[0082] 174 fourth module

[0083] 180 control line

[0084] 190 Actuator

[0085] 200 Sensor-near ASIC

[0086] 210 data bus

Claims

PATENT CLAIMS 1. A method for contactless provision of a function in a motor vehicle (100), comprising the steps of: a) detecting (S2) an approach of a person (120) to the motor vehicle (100); b) detecting (S4) a gesture of the person (120); and c) providing (S5) the function depending on the detection according to steps a) and b); wherein an ultrasonic signal is transmitted and received for the detection in steps a) and b), wherein: (i) a signal repetition rate of the emitted ultrasonic signal is increased in step b) compared to step a); and / or (ii) a repetition rate for receiving the ultrasonic signal in step b) is increased compared to step a).

2. The method according to claim 1, wherein the repetition rate according to (i) and / or (ii) in step a) is between 0.5 and 5 Hz, in particular between 1 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 and 20 Hz, in particular between 7 and 13 Hz.

4. Method according to one of the preceding claims, wherein the motor vehicle (100) has at least one ultrasonic sensor (131 - 136) which is configured to be used for a parking aid, wherein the ultrasonic signal in step a) and / or b) is transmitted and / or received with the aid of the at least one ultrasonic sensor (131 - 136).

5. Method according to one of the preceding claims, wherein exactly two or at least two ultrasonic sensors (131 - 136) are used for transmitting and / or receiving the ultrasonic signal in step a) and / or b).

6. Method according to one of the preceding claims, wherein at least two ultrasonic sensors (131 - 136) alternately transmit ultrasonic signals.

7. Method according to one of the preceding claims, wherein in step a) hypotheses about the movement of an object are formed using a multi-object tracking method, in particular by means of a random finite set filter, in particular implementations as a so-called probability hypothesis density filter, cardinalized 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 approximations thereof, and if a hypothesis predicts the approach of a person (120) with a probability above a predetermined probability, step b) is carried out.

8. Method according to one of the preceding claims, wherein the gesture in step b) comprises an arm movement, a foot movement towards a bumper of the motor vehicle (100), a stepping movement forwards and backwards or a stepping movement to the side and back.

9. Method according to one of the preceding claims, wherein step a) is carried out when or while a smart key (150) belonging to the motor vehicle (100) is in communication with the motor vehicle (100) and the motor vehicle (100) is in the parked position.

10. Method according to one of the preceding claims, wherein between steps a) and b) a stopping (S3) of the person (120) in a target area (140) is detected.

11. Method according to claim 10, wherein for the detection of the stoppage (S3) a further ultrasonic signal is transmitted and received, which comprises pulses or pulse sequences, and wherein: (i) a signal repetition rate of the transmitted further ultrasonic signal is increased compared to the signal repetition rate of the transmitted ultrasonic signal in step a); and / or (ii) a repetition rate for receiving the further ultrasonic signal is increased compared to the repetition rate for receiving the ultrasonic signal according to step a).

12. Method according to one of the preceding claims, wherein the function according to step c) comprises a contactless opening of a driver's door, a passenger door, a front door, a rear door, a trunk door or tailgate, a front door or front flap, or a door for a power connection or for a fuel filler opening and / or the gesture according to step b) is an opening gesture.

13. A device for contactlessly providing a function in a motor vehicle (100), comprising: a first detection unit (171) for detecting an approach of a person (120) to the motor vehicle (100); a second detection unit (173) for detecting a gesture of the person (120); and a provision unit (174, 180, 190) for providing the function depending on the detection using the first and second detection units; wherein the first and second detection units are configured to transmit and receive a respective ultrasonic signal comprising pulses or pulse sequences, and wherein: (i) a frequency of the pulses or pulse sequences of the emitted ultrasonic signal is increased in the second detection unit compared to the first detection unit; and / or (ii) a frequency for sampling the ultrasonic signal upon reception of the same at the second detection unit is increased compared to the first detection unit.

14. Motor vehicle (100) with a 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 (170) to carry out the method according to any one of claims 1-12.

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