Method for cleaning vehicle sensors and unmanned aerial vehicle for use with such method

Abstract

The invention relates to a method for cleaning vehicle sensors, wherein position data of a vehicle are received (1). An unmanned aerial vehicle suitable for cleaning vehicle sensors is flown (2) to the vehicle based on the received position data of the vehicle, is positioned (3) in the vicinity of the vehicle based on the position data of the sensor to be cleaned of the vehicle in such a way that cleaning of the sensor to be cleaned is possible, and is cleaned (4). The vehicle can transmit the position data of the vehicle to a service station via a mobile data connection, which causes the unmanned aerial vehicle to fly to the vehicle and, after the cleaning process has been completed, to return (5) to the service station.

Description

Technical Field

[0001] The invention relates to a method for cleaning vehicle sensors, in particular for cleaning vehicle sensors of an autonomously driven vehicle. The invention also relates to an unmanned aerial vehicle for use in such a method. Background Art

[0002] A large number of sensors are installed in today's vehicles. Therefore, driver assistance systems require continuous monitoring of the vehicle's surroundings by means of sensors in order to support the driver in the case of driving tasks and to inform him of possible dangerous situations at an early stage. Sensor detection of the vehicle's surroundings is becoming increasingly important for autonomous vehicles, since autonomous driving of autonomous vehicles is only possible if lanes and possible obstacles are detected. Different types of sensors based on different technologies can be used for the recognition of the surroundings, wherein a particularly reliable image of the environment is often generated by combining the data of different sensors, that is to say by so-called sensor fusion. In addition to radar and ultrasonic sensors, sensors based on optical detection of the environment are used in particular.

[0003] Thus, detailed image information from one or more cameras of the vehicle's surroundings can be evaluated, wherein traffic signs or other objects and (when using stereo cameras) the distance and speed of possible obstacles can also be detected. Similarly, the vehicle's surroundings can be scanned and observed with laser light at high resolution and independently of the external light conditions by one or more lidar sensors (Light Detection and Ranging).

[0004] Especially for autonomous vehicles, it is necessary that the sensor detection of the vehicle's surroundings functions correctly at all times. Only in this way can it be ensured, for example, that obstacles can be detected early and can be reacted to appropriately. However, in the case of sensor contamination, especially in the case of optical methods such as LIDAR, it may result that the vehicle's surroundings can no longer be detected correctly and the vehicle can no longer be driven safely.

[0005] In this case, the sensors must be cleaned before further driving can be carried out safely. For this purpose, the passengers may be asked to get out of the vehicle after it has come to a stop and clean the sensors. In the case of an autonomous vehicle driving without passengers, the vehicle is however requested to request external assistance, since no passengers can get out of the vehicle in order to remove the contaminants. In addition, the vehicle can activate an automatic cleaning facility if the contaminants are detected early enough and the current level of contamination still allows this.

[0006] Likewise, automatic cleaning systems for various sensors can be fixedly installed on the vehicle, wherein all safety-critical sensors must be equipped with such a cleaning system. However, such cleaning systems increase the cost of the vehicle and also require additional installation space for the cleaning system.

[0007] In particular, if severe contamination of the sensors is to occur only rarely, it may be more cost-effective over the life of the vehicle to commission a service provider who can manually remove the contamination instead of using an automatic cleaning system in the event of contamination. To this end, the service provider will drive to the relevant vehicle if necessary in order to clean the contaminated sensor. However, this may require a relatively long time, depending on the distance, traffic route and traffic volume. During this time period, the vehicle cannot then carry out its driving task, which may lead to problems, especially in the case of time-critical transport tasks.

[0008] For immovable objects (such as buildings), it is known to use unmanned aerial vehicles for cleaning. Thus, DE 10 2014 009 903 A1 discloses a method for controlling a flying object for cleaning a glass facade or surface of a solar module of a solar power station. The surface can be cleaned by a cleaning device (such as a brush) at the flying object or by an airflow caused by a rotor, wherein the cleaning device can be controlled independently of the flight control device. The method comprises detecting the surface of the object to be cleaned, orienting the flying object relative to the surface and constructing a flight trajectory. As a result, the surface can be cleaned particularly efficiently.

[0009] Likewise, DE 10 2014 116 821 A1 describes an unmanned rotary-wing aircraft that can be used to treat surfaces such as building walls. Here, the unmanned rotary-wing aircraft has a connection area for a hose of a pumpable payload that is reserved in a container outside the rotary-wing aircraft and a working device for treating the payload. For example, the payload can be applied to a surface in the environment of the aircraft or sprayed into the air by the aircraft. The working device can be configured as a brush or roller brush or nozzle for applying paint to a building facade, as a sandblaster for cleaning a building facade, or as a window cleaner.

[0010] Finally, WO 2013 / 07671 1A2 discloses a remote-controlled mini-copter with a cleaning brush for cleaning the glass of the facades of tall buildings, which moves up and down relative to the glass to be cleaned. During the cleaning process, the mini-copter is connected to a safety rope mounted on the top and to a load vehicle. The load vehicle supplies the mini-copter with cleaning liquid and has a control panel in the load vehicle cabin to monitor and control the cleaning process. Summary of the invention

[0011] The object of the present invention is to provide an improved method for cleaning vehicle sensors, in particular for cleaning vehicle sensors of an autonomously travelling vehicle.

[0012] This object is achieved by a method according to the invention and by a corresponding unmanned aerial vehicle according to the invention. The invention has a number of preferred embodiments.

[0013] In the method for cleaning vehicle sensors according to the invention, position data of the vehicle are received. An unmanned aerial vehicle suitable for cleaning vehicle sensors flies to the vehicle based on the received position data of the vehicle, is positioned in the vicinity of the vehicle based on the position data of the sensor to be cleaned of the vehicle so that cleaning of the sensor to be cleaned is possible, and cleans the sensor.

[0014] While unmanned aerial vehicles are currently only used to clean immovable objects, according to the invention, cleaning of vehicle sensors can also be achieved by suitable unmanned aerial vehicles by recognizing and using the position data of the vehicle and the position data of the sensor to be cleaned. Since the unmanned aerial vehicle can run to the vehicle on a direct route independent of traffic lights and traffic, it can reach the vehicle very quickly, so that the contaminated sensor can be cleaned immediately and the possibly interrupted journey can be continued. It can thus also be omitted to equip the vehicle with an additional sensor cleaning system, so that the above-mentioned disadvantages can be avoided.

[0015] According to one embodiment of the invention, the vehicle sends the position data of the vehicle to the service station via a mobile data connection. The service station receives the sent position data and then causes the unmanned aerial vehicle to fly to the vehicle. After the cleaning process is finished, the unmanned aerial vehicle then returns to the service station.

[0016] A large number of unmanned aerial vehicles can be kept in reserve at such a service station, so that even in the case of covering a larger geographical area it can be ensured that all vehicles can be searched quickly even in the case of multiple requests for cleaning the sensors of different vehicles arriving simultaneously.

[0017] According to one embodiment of the invention, the contamination of the sensor is detected by the vehicle. This makes it possible to react immediately to the contamination and to make a targeted request for cleaning of the sensor when the sensor is contaminated and thus threatens the continued driving of the vehicle.

[0018] Thus, the autonomously traveling vehicle can advantageously be stopped automatically when safe driving operation is no longer ensured due to contamination of the sensors.

[0019] In this way, a threat to the vehicle or other road users can be avoided if the occupants of the autonomous vehicle do not respond to the request to clean the sensors or if the vehicle is driving without a passenger.

[0020] Likewise, the vehicle can advantageously send a report about a contaminated sensor to a service station via a mobile data connection. This enables the service station to, for example, determine the urgency of cleaning or, in the case of different capabilities of different unmanned aerial vehicles, select a suitable aircraft for cleaning a contaminated sensor.

[0021] Furthermore, the vehicle can send information about the vehicle model and / or the position data of the sensor to be cleaned in the vehicle-fixed coordinate system to the service station via a mobile data connection, and the service station sends information about the vehicle model and / or the position data or data derived therefrom to the unmanned aerial vehicle. Since the sensors are installed in different areas of the vehicle body in different vehicle models, this makes it easier for the aerial vehicle to find the sensor to be cleaned on the vehicle and to position it appropriately for cleaning.

[0022] Accordingly, the UAV for cleaning vehicle sensors according to the present invention comprises: a drive unit with a plurality of rotors driven by motors, which generates lift and / or propulsion for the UAV;

[0023] a navigation unit for navigating to the vehicle based on the position data of the vehicle and for navigating at the vehicle based on the position data of sensors of the vehicle to be cleaned;

[0024] - a control unit, which controls the drive unit with the aid of navigation data from the navigation unit in such a way that the UAV flies to the vehicle and can be positioned in the vicinity of the vehicle in such a way that cleaning of the sensor to be cleaned is possible; and - a cleaning unit, which is suitable for carrying out cleaning of the sensor to be cleaned.

[0025] Advantageously, a camera unit and an evaluation unit are provided in the UAV, wherein the evaluation unit for optically detecting the sensor to be cleaned by means of the camera unit determines the position of the sensor relative to the UAV. This enables the cleaning unit to be positioned as precisely as possible in front of the sensor to be cleaned.

[0026] According to one embodiment of the invention, the cleaning unit has a compressed air tank which is connected to an electronically controllable valve via a pressure reducer and a compressed air cleaner.

[0027] Since contactless cleaning is achieved in this embodiment, this enables relatively simple navigation of the UAV even in poor weather conditions, such as strong or gusty winds.

[0028] In this case, the cleaning unit advantageously has a liquid tank for the cleaning liquid, wherein the cleaning liquid is mixed with compressed air so that the surface to be cleaned is sprayed with the air-liquid mixture.

[0029] By using a cleaning liquid, the cleaning effect can be significantly increased, particularly in the case of fixed contamination.

[0030] According to a further embodiment of the invention, the cleaning unit can be lowered by means of a capstan or a telescopic rod in order to position the cleaning unit in front of the sensor to be cleaned.

[0031] Since the cleaning unit is not rigidly connected to the UAV in this embodiment, the UAV can fly over the vehicle and only lower the cleaning device, which can be advantageous, for example, in confined space conditions.

[0032] In this case, the cleaning unit advantageously has the following features:

[0033] one or more motor-driven cleaning brushes which are set in rotation for cleaning the sensor to be cleaned;

[0034] - Cleaning liquid tanks;

[0035] a nozzle, with which the cleaning liquid is sprayed onto the sensor to be cleaned;

[0036] a pump which extracts cleaning liquid from the cleaning liquid tank and supplies it to the nozzles; and

[0037] A motor-driven propeller which is arranged in such a way that a contact force is generated for the cleaning brush which acts on the sensor to be cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Additional features of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

[0039] Figure 1 The method according to the invention for cleaning a vehicle sensor with an unmanned aerial vehicle is schematically shown;

[0040] Figure 2 A first embodiment of an unmanned aerial vehicle according to the present invention is schematically shown; and

[0041] Figure 3 A side view (a) and a top view (b) of a second embodiment of an unmanned aerial vehicle according to the present invention are schematically shown. DETAILED DESCRIPTION

[0042] In order to better understand the principle of the present invention, the following describes the embodiments of the present invention in more detail with the help of the accompanying drawings. Obviously, the present invention is not limited to these embodiments and the described features can also be combined or modified without leaving the scope of protection of the present invention.

[0043] Figure 1The flow chart of the method according to the invention is schematically shown. First, the position of the vehicle in which the cleaning of the sensors is to be performed must be determined. This can be done, for example, with the aid of a GPS receiver of the vehicle's navigation system. The vehicle then sends the current position data of the vehicle via a mobile data connection to a service station, which operates at least one unmanned aerial vehicle, but preferably a plurality of such aerial vehicles, for cleaning the vehicle sensors. Such a service station can be operated, for example, by the vehicle manufacturer itself, a workshop for motor vehicles or a service company specializing in cleaning vehicle sensors.

[0044] The unmanned aerial vehicle can in particular be a so-called multicopter with multiple motor-driven rotors, for example a tricopter (with three motors), a quadcopter (with four motors), a hexacopter (with six motors) or an octacopter (with eight motors), which is provided with a cleaning unit for cleaning vehicle sensors as described further below.

[0045] The position data of the vehicle are then received by the unmanned aerial vehicle via the service station in method step 1. However, it is also possible for the current position data of the vehicle to be sent directly to an unmanned aerial vehicle in the vicinity of the vehicle via a mobile data connection and to be received directly by the unmanned aerial vehicle.

[0046] The service station then causes the unmanned aerial vehicle to move to the vehicle for cleaning the sensor, which then flies to the vehicle position of the vehicle in method step 2. The unmanned aerial vehicle can be at the service station and charged there and optionally provided with cleaning liquid, or it can still be in flight, for example, on the way back from a previous cleaning of a sensor of another vehicle. In this case, the service station can select one of the available unmanned aerial vehicles based on different criteria. Thus, for example, when there is information about which vehicle sensor is to be cleaned, an unmanned aerial vehicle with a cleaning unit that is particularly suitable for this vehicle sensor is sent out. Similarly, in particularly urgent cleaning situations, an unmanned aerial vehicle can be selected that can reach the relevant vehicle particularly quickly due to the relatively high flight speed. Similarly, for this purpose or also in order to minimize flight costs, an unmanned aerial vehicle that is already in flight and is as close to the relevant vehicle as possible is dispatched to the vehicle.

[0047] If it can be assumed that the vehicle has not changed its position since the initial transmission of the position data, for example because the vehicle had stopped at the roadside when the position data were transmitted to wait for the cleaning of the sensors, then the vehicle position flown to corresponds to the initial position data of the vehicle. For this vehicle position, the flight path of the UAV is then determined by the service station or by the UAV itself.

[0048] Likewise, the vehicle can also continue to move after the initial transmission of the position data. In this case, it can be provided that the vehicle transmits its respective current position at regular intervals, so that the flight path of the unmanned aerial vehicle can be adapted. It can also be provided that during the initial transmission of the position data, data about the programmed route are transmitted by the navigation device of the vehicle and used for the estimation of future position data. Thus, the unmanned aerial vehicle can, for example, head for the driving destination of the programmed route in order to clean the vehicle sensors there. Likewise, based on the routes and estimated speeds of the vehicle and the unmanned aerial vehicle, the earliest possible meeting point can be determined.

[0049] After the UAV has reached the vehicle position, it is oriented relative to the vehicle sensor to be cleaned in method step 3. For this purpose, the position data of the sensor to be cleaned can be evaluated, which can be transmitted to the UAV by a service station or by the vehicle or can also be directly present in the memory of the UAV. Likewise, the vehicle sensor can be detected by one or more sensors located at the UAV. Thus, for example, the exact position of the sensor to be cleaned can be determined using a camera and suitable image recognition algorithms. It can also be provided that people, buildings or other air traffic participants located nearby can be identified with the help of a camera so that they can be avoided and a collision can be avoided if necessary. Likewise, a separate camera can also be used for this purpose.

[0050] The cleaning of the vehicle sensors by means of the cleaning unit of the UAV then takes place in method step 4, wherein it is ensured that the relative position of the UAV with respect to the vehicle is maintained during the cleaning process. The cleaning can be carried out for a predefined time period, which, according to the invention, is sufficient to clean the corresponding vehicle sensors. However, it can also be provided that the progress of the cleaning is controlled, for example by optical detection by means of the above-mentioned camera.

[0051] After the cleaning process is finished, the UAV then preferably flies back to the service station according to method step 5, so that it can be recharged there and thus be available for new cleaning tasks. However, it can also be provided that the UAV first also flies to another vehicle for a cleaning task before it returns to the service station.

[0052] In this case, both the flight to the vehicle and the cleaning of the vehicle sensors can be carried out autonomously by the unmanned aerial vehicle, which can however also be monitored and directed by a service station, particularly in the case of difficult boundary conditions during the flight or cleaning phase.

[0053] In addition to cleaning the vehicle sensors as immediately as possible due to detected contamination of the vehicle sensors, it is also conceivable to carry out cleaning at regular service intervals independently of the detected contamination in the event of increasing contamination over time.

[0054] A first embodiment of the unmanned aerial vehicle according to the present invention is Figure 2 In this case, the UAV is located above the schematically depicted roof 6 of the vehicle in front of a sensor 7 of the vehicle, for example a lidar sensor mounted on the roof.

[0055] The unmanned aerial vehicle has a drive unit with a plurality of motor-driven rotors 8, which generate lift and / or propulsion for the unmanned aerial vehicle. In addition, a navigation unit 9 is provided for navigating to the vehicle based on the position data of the vehicle and for navigating at the vehicle based on the position data of the sensor to be cleaned. The control unit 10 controls the drive unit with the help of the navigation data of the navigation unit 9 so that the unmanned aerial vehicle can fly to the vehicle and can be positioned in the vicinity of the vehicle so that the cleaning of the sensor 7 to be cleaned is possible. For the purpose of precise positioning during the cleaning process, a camera unit 11 is provided for optically detecting the sensor to be cleaned. The image data generated by the camera unit 11 is supplied to the evaluation unit 12 for this purpose, which determines the exact position of the sensor to be cleaned by means of a suitable image recognition algorithm and supplies information about this to the control unit 10.

[0056] The actual cleaning unit for cleaning the sensor is designed as follows in this embodiment. A compressed air tank 13 filled with compressed air is provided. The compressed air tank 13 can be removable so that an empty compressed air tank can be quickly replaced by a prefilled compressed air tank when the UAV is on the ground at a service station, or the compressed air tank can also be fixedly connected to the UAV.

[0057] The compressed air tank 13 is connected to an electronically controllable valve via a pressure reducer and a compressed air cleaner. When the valve is actuated, air then flows out through the nozzle 14. In addition, cleaning liquid is drawn from a tank 15 for cleaning liquid, whereby the surface to be cleaned can be sprayed with a mixture of cleaning liquid and air. It can be provided that the position of the nozzle is adapted or changed during the cleaning process by a regulating device provided for this purpose (e.g. a servomotor).

[0058] A cleaning unit for a second embodiment of an unmanned aerial vehicle according to the invention is provided in Figure 3. Here, the cleaning unit can be lowered by the unmanned aerial vehicle for the cleaning process via a winch disc 16 or a telescopic rod and thus positioned in front of the sensor to be cleaned. For cleaning, one or more brushes 17 are provided, which can be set in rotation by a motor. In addition, a tank 15 for cleaning liquid is also provided here. The cleaning liquid is sprayed onto the sensor to be cleaned via a nozzle 14 using a pump. The brush 17 then rotates on the part to be cleaned, wherein the required pressing force is generated by one or more propellers 18 driven by a motor arranged opposite to each other. After the cleaning process, the cleaning unit is transported upwards to the initial position again so as not to cause an obstruction during continued flight or return to the service station.

[0059] The present invention may be used to clean any externally accessible vehicle sensor on any vehicle.

[0060] List of reference numerals:

[0061] 1. Method step, in which position data of a vehicle is received

[0062] 2. Method steps, wherein the unmanned aerial vehicle flies to the vehicle position

[0063] 3. Method step, in which the UAV is oriented relative to the sensor

[0064] 4 Method steps in which the UAV cleans the sensor

[0065] 5 method steps, in which the UAV flies back to the service station

[0066] 6 Top of vehicle

[0067] 7 Vehicle Sensors

[0068] 8 Rotor

[0069] 9 Navigation Unit

[0070] 10 Control unit

[0071] 11 Camera Unit

[0072] 12 Evaluation Units

[0073] 13 Compressed air tank

[0074] 14 Nozzle

[0075] 15 Cleaning liquid tank

[0076] 16. Noose Coil

[0077] 17 Brush

[0078] 18 Motor driven propeller for clamping force

Claims

1. A method for cleaning a vehicle sensor, wherein: - receiving from a navigation device of the vehicle (1) data on a programmed route and an estimate of future position data of the vehicle; - determining the earliest possible meeting point based on the estimated speed of the vehicle and the programmed route, i.e. the route of the vehicle and the route and estimated speed of the UAV, wherein the UAV is a UAV suitable for cleaning the vehicle's sensors, - the unmanned aerial vehicle flies (2) to the meeting point; The UAV is positioned (3) in the vicinity of the vehicle based on the position data of the sensor to be cleaned of the vehicle in such a way that cleaning of the sensor to be cleaned is possible; and - The UAV cleans (4) the sensor (7).

2. The method according to claim 1, wherein: The method further comprises the following steps: - the vehicle sends the data to the service station via a mobile data connection; - the service station receives the data and causes the UAV to fly to the vehicle; and - After the cleaning process is completed, the UAV returns (5) to the service station.

3. The method according to claim 1 or 2, wherein: Contamination of the sensor (7) is detected by the vehicle.

4. The method according to claim 3, wherein: The vehicle is an autonomous vehicle and the autonomous vehicle is automatically stopped only when a safe driving operation is no longer ensured due to contamination of the sensor.

5. The method according to claim 2, wherein: Contamination of the sensor (7) is detected by the vehicle, wherein the vehicle sends information about the contaminated sensor to the service station via the mobile data connection.

6. The method according to claim 5, wherein: The vehicle sends information about the vehicle model and / or position data of the sensor to be cleaned in a vehicle-fixed coordinate system to the service station via the mobile data connection, and the service station sends information about the vehicle model and / or position data or data derived therefrom to the unmanned aerial vehicle.

7. An unmanned aerial vehicle for performing the method for cleaning a vehicle sensor according to any one of claims 1 to 6, having - a drive unit with a plurality of motor-driven rotors (8) which generate lift and / or propulsion for the UAV; a navigation unit (9) for navigating to the meeting point and for navigating at the vehicle based on position data of the sensor (7) to be cleaned of the vehicle; a control unit (10) which controls the drive unit with the aid of navigation data from the navigation unit in such a way that the UAV can fly to the meeting point and position itself in the vicinity of the vehicle in such a way that cleaning of the sensor to be cleaned is possible; and - A cleaning unit, which is suitable for performing cleaning of the sensor to be cleaned.

8. The unmanned aerial vehicle according to claim 7, wherein: A camera unit (11) and an evaluation unit (12) are provided, wherein the evaluation unit (12) is used to determine the position of the sensor to be cleaned by optically capturing the sensor with the aid of the camera unit relative to the UAV.

9. The unmanned aerial vehicle according to claim 7 or 8, wherein: The cleaning unit has a compressed air tank (13) which is connected to an electronically controllable valve via a pressure reducer and a compressed air cleaner.

10. The unmanned aerial vehicle according to claim 9, wherein: The cleaning unit has a cleaning liquid tank (15) and the cleaning liquid is mixed with compressed air so that the surface to be cleaned is sprayed with the air-liquid mixture.

11. The unmanned aerial vehicle according to claim 7 or 8, wherein: The cleaning unit can be lowered by means of a winch (16) or a telescopic rod in order to position the cleaning unit in front of the sensor to be cleaned.

12. The unmanned aerial vehicle according to claim 11, wherein: The cleaning unit has the following features: - one or more motor-driven cleaning brushes (17) which are set in rotation for cleaning the sensor to be cleaned; - Cleaning liquid tank (15); - a nozzle (14) with which a cleaning liquid is sprayed onto the sensor to be cleaned; - a pump which extracts the cleaning liquid from the cleaning liquid tank (15) and supplies it to the nozzle; and A motor-driven propeller (18) is arranged in such a way that a contact force is generated for the cleaning brush on the sensor to be cleaned.

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