Control of a safety function of a motor vehicle

Abstract

A method (200) for controlling a safety function of a motor vehicle (105) comprises steps of initiating (205) a wireless connection between a handheld device (110) and the motor vehicle (105); determining (210) an expected data volume to be transmitted via the interface (145); determining (245) a time interval depending on the expected data volume; and periodically activating (255) the connection at the time interval.

Description

The present invention relates to the control of a motor vehicle. In particular, the invention relates to the control of a safety function of the motor vehicle.A motor vehicle can be equipped with a safety device in order to protect a safety function against unauthorized use. The safety function can comprise, for example, releasing or closing a immobilizer, locking a door, a flap or a window of the motor vehicle. The safety function can be controlled by means of a mobile device, which is in particular designed as a smartphone. A wireless connection can be established between the mobile device and the motor vehicle. The mobile device and the motor vehicle can each authenticate each other via the connection, and a predetermined security function of the motor vehicle can be controlled by means of the mobile device. The safety function, for example the opening of a locking system, can be explicitly requested by a user of the mobile device or can be automatically triggered, for example if the mobile device is sufficiently close to the motor vehicle.The security function can be controlled, for example, by means of a technique known as a digital car key. A corresponding specification under the designation Digital Key Release 3 is present, for example, in version 1.1.0 of 20 July 2022.In order to control the safety function of the motor vehicle, the wireless connection is required. The initiation of the connection can be much more energy-intensive than maintenance. It is therefore usual, after it is initiated, to activate at regular intervals. For this purpose, the mobile device and the motor vehicle can negotiate a time interval. The shorter the time interval, the faster an occurring volume of data can be transmitted via the connection. The greater the time interval, the lower an energy required to maintain the connection. This conflict of goals is usually solved by a compromise. For example, the time interval may be about 30 ms.In order not to restrict the use of the safety function of the motor vehicle to a mobile device, a dedicated handheld device which provides a corresponding functionality can also be used instead. In order to make the hand-held device as small and light as possible, a built-in energy source can be of small dimensions. It is therefore of interest to operate the hand-held device in such a way that as little electrical energy as possible is used.An object on which the present invention is based is to provide an improved technique for controlling a safety function of a motor vehicle by means of a hand-held device. The invention achieves this object by means of the subject matter of the independent claims. Dependent claims represent preferred embodiments.A method for controlling a safety function of a motor vehicle comprises steps of initiating a wireless connection between a hand-held device and the motor vehicle; determining an expected volume of data to be transmitted via the connection; determining a time interval depending on the expected volume of data; and periodically activating the connection with the time interval.In contrast to a known technique, in which the time interval is determined only once for the connection, the conflict of goals between a fast and an energy-saving transmission can be solved in an improved manner by dynamically adapting the time interval. If no significant volume of data is expected, the time interval can be chosen to be long, so that energy for maintaining the connection can be saved. If, on the other hand, a significant volume of data is expected, the time interval can be shortened, so that a latency period until the transmission of arrived data can be low. A reaction speed of the motor vehicle to data to be transmitted may be high.The regular activation is preferably carried out on the part of the hand-held device. An energy consumption of the hand-held device for maintaining the connection can thereby be reduced. Unlike on the part of the motor vehicle, only little energy can be available on the part of the hand-held device. Optionally, the regular activation can also be carried out by the motor vehicle. The determination of the time interval and the preceding determination of an expected data volume are preferably also carried out by the hand-held device.The safety function on board the motor vehicle may not be controllable without further aids. In particular, the safety function may require the use of a handheld device described herein. A direct control of the safety function is usually not provided. The operation of the safety function can be controlled manually or automatically using the hand-held device. In particular, the safety function can be configured to prevent unauthorized use of the motor vehicle. The safety function can comprise releasing or closing a immobilizer, opening or closing a door, a window or a flap of the motor vehicle. Furthermore, a child safety device can be controlled by means of the safety function. Further safety functions can also be controlled in this manner.It is generally preferred that the safety function of the motor vehicle is secured in the manner of a digital vehicle key, in particular the digital car key which is defined by the car connectivity consortium. To comply with a specified standard for protecting the safety function, further steps may also be required.It is preferred that the time interval between the hand-held device and the motor vehicle is adjusted. The tuning may include a hand-held setting or a negotiation between the hand-held device and the motor vehicle. The negotiation may include proposing one or more time intervals by the handheld device and confirming one of the time intervals by the motor vehicle. Data can be transmitted regularly in each case after the expiration of a time interval. A transmitting device and / or a receiving device can only be operated at these times. If the compound cannot be activated several times in sequence, it can be degraded on one side. The control of the safety function is then initially no longer possible. To establish the connection, this must be reinitiated.It is particularly preferred that a probability is determined that a data volume is to be transmitted; the time interval being shortened with increasing probability. With decreasing probability, the time interval can be extended. In other words, the more likely data will be to be transmitted, the more frequently the connection can be activated. The probability of the data volume can be determined in different ways.In one embodiment, the probability is determined on the basis of a movement of the hand-held device relative to the motor vehicle. If a movement takes place, the probability can be high. If no movement or only a slight movement takes place, the probability can be low. The probability may be determined in one or more discrete steps or continuously with respect to the movement of the hand-held device.In a further embodiment, the probability is determined as a function of a movement of the motor vehicle. If the motor vehicle is moving, the probability of data to be transmitted may be low. If the motor vehicle is stationary, the probability may be increased. Here too, the probability can be determined in one or more discrete steps or continuously on the basis of the movement speed.It can be determined whether the hand-held device is moved by a person running. The probability may be determined depending on this determination. If the hand-held device is moved by a person running, a high probability can be assumed, otherwise a low probability. A movement speed of the person can be taken into account in the determination of the level of the probability.In yet another specific embodiment, the probability is determined as a function of a distance between the handheld device and the motor vehicle. If the distance is small, the probability may be high. If the distance is large, the probability may be low.The distance can be determined in different ways. In one embodiment, a connection parameter of an interface over which the connection is handled may be used. Such a parameter may include, for example, a signal strength (RSSI) or a signal-to-noise ratio (SNR). If the signal strength is low or the signal-to-noise ratio is high, a high distance can be assumed. Alternatively, the distance can also be determined by means of a transmission method via the mentioned interface. The connection is preferably established by means of Bluetooth Low Energy (BLE) between the hand-held device and the motor vehicle. A current specification of BLE provides for the determination of a distance between two communication partners. The hand-held device and the motor vehicle can also establish a further connection, which is preferably carried out by means of ultra-broadband technology (UWB). By means of the further connection, a distance and a direction of the hand-held device relative to the motor vehicle can be determined in a further improved manner. The distance determination can be controlled by means of data transmission via the BLE interface.The probability can also be determined as a function of a state of the motor vehicle. If the motor vehicle is parked or parked, for example, a high probability can be assumed. If the motor vehicle is active or is driving, a low probability may apply.In addition to the probability, a capacity of an energy store of the hand-held device can be used for determining the time interval. The more powerful the energy store is, the smaller the time interval can be selected. The energy store can in particular comprise an accumulator or a battery. The performance of such an electrochemical energy store can be determined on the basis of an open circuit voltage, an internal resistance, an ambient temperature or a model. The model can determine a remaining energy on the basis of energy originally present in the energy store and past energy drains. In addition, it can be determined whether it has been observed that a voltage of the electrical energy store has dropped below a predetermined threshold value during the operation of a predetermined load. In this case, the performance of the energy storage device may be determined to be low.A hand-held device for controlling a safety function of a motor vehicle comprises a wireless interface for transmitting data and a processing device. The processing device is configured to initiate a connection with the motor vehicle via the interface; and to activate the connection regularly. In this case, a time interval between activations is determined as a function of an expected volume of data which is to be transmitted via the interface.The hand-held device and in particular its processing device can be configured to partially or completely execute a method described herein. For this purpose, the processing device can be designed electronically and can comprise, for example, an integrated circuit, a programmable logic module or a programmable microcomputer. The method can be realized in the form of a configuration or as a computer program product having program code means for the processing device. The configuration or the computer program product can be stored on a computer-readable data carrier. Features or advantages of the method can be transferred to the device or vice versa.The hand-held device can comprise an electrical energy store for providing a predetermined amount of energy. The energy store can be designed as a rechargeable or non-regenerative energy source. The energy store is preferably electrochemical and can comprise, for example, an accumulator or a battery. The battery can be designed in particular as a button cell.The invention will now be described in more detail with reference to the accompanying drawings, in which: FIG. 1 shows a system; and FIG. 2 shows a flow diagram of a methodillustrated.FIG. 1 shows a system 100 which comprises a motor vehicle 105 and a hand-held device 110. A control device 115 is mounted on board the motor vehicle 105, which is configured to communicate with the hand-held device 110 on the one hand and to control a safety function of the motor vehicle 105 on the other hand. The control device 115 comprises a processing device 120, a first interface 125 and a second interface 130.Both interfaces 125, 130 are implemented wirelessly. The first interface 125 is configured to transmit data between the control device 115 and the hand-held device 110. The first interface 125 preferably operates according to a Bluetooth Low Energy standard.The second interface 130 is likewise configured to communicate with the handheld device 110. However, essentially no data are transported in this case, but a radiometric distance determination takes place. The second interface 130 preferably operates by means of ultra-broadband. On board the motor vehicle 105, a plurality of antennas can be provided, which are comprised by the second interface 130. By transmitting a series of pulses between the different antennas and the handheld device 110, relative distances can be determined. On the basis of the relative distance, it is possible to determine in which direction the hand-held device 110 is located and in which distance it is located.A link 135 may be provided to communicate with another device onboard the motor vehicle 105. The communication can take place in both directions. Thus, the processing device 120 can control a safety function via the further device. Conversely, the further device can provide a state of the motor vehicle 105 to the control device 115.The hand-held device 110 comprises a processing device 140, a first wireless interface 145 which corresponds to the first wireless interface 125 of the motor vehicle 105, and an optional second wireless interface 150 which corresponds to the second wireless interface 130 of the motor vehicle 105. In addition, an energy source 155 is preferably provided. An optional keypad 160 is configured to be actuated by a user to request execution of a predetermined safety function of the motor vehicle 105.The energy source 155 is usually designed as an energy store which is configured to absorb a predetermined amount of energy and provide it to the hand-held device 110. The energy store 155 can comprise, in particular, an accumulator or a battery. The energy store 155 can be fixedly installed in the hand-held device 110 or can be designed to be replaceable.FIG. 2 shows a flow diagram of a method 200 for controlling a safety function of a motor vehicle 105. In a step 205, a wireless connection between the hand-held device 110 and the motor vehicle 105 can be initiated. The connection is preferably effected by means of the first interfaces 125, 145.In a step 210, a probability may be determined with which a volume of data is to be transmitted over the initiated connection. The probability can be determined in different ways. Optionally, different heuristics may be applied that may be combined to determine the probability.For example, in a step 215, a movement of the hand-held device 110 can be determined. The movement can be determined by means of a corresponding sensor on the part of the hand-held device 110, for example an inertial sensor.In a step 220, a movement of the motor vehicle 105 can be determined. A dedicated sensor can likewise be used for this purpose. Alternatively, the movement of the motor vehicle 105 can be determined, for example, on the basis of a speed signal or a series of determined geographical positions of the motor vehicle 105.In a step 225, it can be determined whether the hand-held device 110 is carried by a person running. For this purpose, a movement pattern of the hand-held device 110 with respect to its environment can be determined. The movement pattern is preferably determined by means of an acceleration sensor.In a step 230, a distance of the hand-held device 110 from the motor vehicle 105 can be determined. The distance can be determined on the basis of connection parameters of the connection via the first interface 125, 145, on the basis of a connection parameter or by means of a determination method via the second interface 130, 150.In a step 235, a state of the motor vehicle 105 may be determined. The state may indicate, in particular, whether motor vehicle 105 is parked, whether it is ready for driving, and / or whether it is driving.The likelihood of the imminent volume of data may be determined by checking one or more indicators of steps 215 to 235.In a step 240, a power capability of the energy source 155 of the handheld device 110 can be determined. The performance indicates how much energy is removable from the energy source 155. In particular, the performance may relate to residual energy that can be drawn from the energy source 155.In a step 245, a time interval for activating the connection between the first interfaces 125, 145 can be determined. The time interval is preferably determined by the hand-held device 110 and on the basis of the probability determined in step 210 and / or the performance of the energy source 155 determined in step 240.In a step 250, the determined time interval between the hand-held device 110 and the motor vehicle 105 can be adjusted. For this purpose, the time interval can be transmitted from the hand-held device 110 to the motor vehicle 105 or its control device 115. The time interval can be provided as a conditional specification or a time interval between the hand-held device 110 and the motor vehicle 105 can be negotiated, wherein the hand-held device 110 preferably attempts to place the time interval as close as possible to the previously determined time interval.In a step 255, the connection existing between the first interfaces 125, 145 can be activated regularly on the basis of the negotiated time interval. If the connection is active, ready data can be transmitted. In one embodiment, a predetermined amount of data may be transmitted upon each activation of the connection. In another embodiment, after the connection is activated, as much data as is available for transmission can be transmitted. Only then can the connection be activated again periodically. In phases in which the connection is not activated, the interfaces 125, 145 may be deactivated.Reference numerals denote reference numerals100 System 105 Motor vehicle 110 Hand-held device 115 Control device 120 Processing device 125 First interface 130 Second interface 135 Connection 140 Processing device 145 First interface 150 Second interface 155 Energy source 160 Keypad 200 Method 205 Connection initiate 210 Probability of a data volume determine 215 Movement of the hand-held device determine 220 Movement of the motor vehicle determine 225 Moving person determine 230 Distance of the hand-held device from the motor vehicle determine 235 State of the motor vehicle determine 240 Capability of the energy source determine 245 Time interval determine 250 Time interval tune 255 Connection regularly activate

Claims

Method (200) for controlling a safety function of a motor vehicle (105), wherein the method (200) comprises the following steps: - initiating (205) a wireless connection between a hand-held device (110) and the motor vehicle (105); - determining (210) an expected volume of data to be transmitted via the connection; - determining (245) a time interval depending on the expected volume of data; and - periodically activating (255) the connection with the time interval.Method (200) according to claim 1, wherein the regular activation (255) is effected by the hand-held device (110).Method (200) according to claim 1 or 2, wherein the safety function on board the motor vehicle (105) is controllable only using a hand-held device (110).Method (200) according to one of the preceding claims, wherein the time interval between the hand-held device (110) and the motor vehicle (105) is adjusted (250).The method (200) according to any one of the preceding claims, further comprising determining (210) a probability that a volume of data is to be transmitted; wherein the time interval is shortened with increasing probability.The method (200) according to claim 5, wherein the probability is determined on the basis of a movement (215) of the hand-held device (110) with respect to the motor vehicle (105).Method (200) according to Claim 5 or 6, wherein the probability is determined as a function of a movement (220) of the motor vehicle (105).The method (200) according to any one of claims 5 to 7, wherein it is determined (225) whether the hand-held device (110) is moved by a current person; and the probability is determined depending thereon.Method (200) according to one of Claims 5 to 8, wherein the probability is determined as a function of a distance (230) between the hand-held device (110) and the motor vehicle (105).Method (200) according to one of Claims 5 to 9, the probability being determined as a function of a state (235) of the motor vehicle (105).Method (200) according to one of the preceding claims, wherein the time interval is determined (245) as a function of a power capability (240) of an energy store of the hand-held device (110).Hand-held device (110) for controlling a safety function of a motor vehicle (105), wherein the hand-held device (110) comprises the following elements: - a wireless interface (145) for transmitting data; and - a processing device (140) which is configured to: + initiate a connection to the motor vehicle (105) via the interface (145); and + activate the connection on a regular basis; characterized in that + a time interval between activations is determined as a function of an expected volume of data which is to be transmitted via the interface (145).The hand-held device (110) according to claim 12, further comprising an electrical energy store (155) for providing a predetermined amount of energy.

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