ARTIFICIAL TURF MAINTENANCE ROBOT

Abstract

The invention provides for a method of maintaining artificial turf using a turf maintenance robot. The artificial turf comprises an artificial turf carpet, wherein the artificial turf carpet comprises turf fibers which form an artificial turf surface. The artificial turf fibers have a grain. The artificial turf comprises artificial turf infill distributed between the artificial turf fibers. The turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises a memory for storing turf grain data, descriptive the grain of the artificial turf fibers. The method comprises brushing the artificial turf surface by the turf maintenance robot. The turf maintenance robot performs the brushing dependent upon the turf grain data.

Claims

1. A method of maintaining artificial turf using a turf maintenance robot (300), wherein the artificial turf comprises an artificial turf carpet, wherein the artificial turf carpet comprises turf fibers which form an artificial turf surface, wherein the artificial turf fibers have a grain, wherein the artificial turf comprises artificial turf infill distributed between the artificial turf fibers, wherein the turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises a memory for storing turf grain data descriptive of the grain of the artificial turf fibers, the method comprising brushing the artificial turf surface by the turf maintenance robot, whereby the turf maintenance robot performs the brushing dependent upon the turf grain data.

2. The method of claim 1, wherein the method further comprises: controlling a drone to fly over the artificial turf and acquire artificial turf data descriptive of the artificial turf, wherein the drone comprises a sensor configured for acquiring the artificial turf data; and controlling the turf maintenance robot to perform maintenance on the artificial turf using the artificial turf data.

3. The method of claim 2, wherein the artificial turf data comprises image data; wherein the method further comprises: identifying at least one maintenance zone within the artificial turf by inputting the image data into an image classification module; and controlling the turf maintenance robot to perform maintenance on the at least one maintenance zone.

4-5. (canceled)

6. The method of claim 3, wherein the image classification module is configured for identifying the at least one maintenance zone using any one of the following: detecting a color difference in the turf images; detecting a spatially dependent reflectivity of the artificial turf; detecting a pile direction pattern in the turf images; and combinations thereof.

7. (canceled)

8. The method of claim 2, wherein performing maintenance on the artificial turf comprises any one of the following: cleaning a surface of the artificial turf; the brushing of the artificial turf; redistributing artificial turf infill; and combinations thereof.

9-10. (canceled)

11. The method of claim 1, wherein the turf maintenance robot comprises a positioning system for determining a current location, wherein the brushing of the artificial turf surface is at least partially determined by the current location.

12-14. (canceled)

15. The method of claim 1, wherein the turf maintenance robot comprises at least one optical sensor configured for acquiring optical data descriptive of the artificial turf surface within a field of view of the at least one optical sensor, wherein the method further comprises: acquiring the optical data using the at least one optical sensor; and using the controller to at least partially determining the turf grain data using the optical data.

16-17. (canceled)

18. The method of claim 1, wherein the turf maintenance robot comprises a usage meter for recording usage data; wherein the usage data comprises any one of the following: a time usage data, distance traveled usage data, and combinations thereof; wherein the method further comprises recording the usage data using the usage meter; and wherein the method further comprises generating repair instructions using at least partially the usage data.

19. The method of claim 18, wherein the method further comprises generating an invoice using the usage data.

20-27. (canceled)

28. The method of claim 1, wherein the brushing of the artificial turf surface comprises: calculating a cross brushing path using at least partially the turf grain data; and controlling the turf maintenance robot to follow the cross brushing path.

29. The method of claim 1, wherein method further comprises controlling the turf maintenance robot to travel between multiple artificial turf surfaces.

30. The method of claim 1, wherein the turf maintenance robot further comprises at least one RFID reader, wherein the method further comprises at least partially determining the turf grain data using the at least one RFID reader.

31. The method of claim 30, wherein the artificial turf comprises an artificial turf carpet with a backing, wherein the backing comprises RFID data carriers, wherein the RFID data carriers contain local turf data, wherein the local turf data at least partially comprises the turf grain data, wherein the controller is configured for at least partially receiving the turf grain data from the RFID data carriers by reading the local turf data from the RFID data carriers with the at least one RFID reader.

32. The method of claim 1, wherein artificial turf fibers comprise an optical path marked with fluorescent dye markers, wherein the self propelled robot comprises at least one optical sensor configured for acquiring optical data descriptive of the artificial turf surface within a field of view of the at least one optical sensor, wherein the controller is configured for detecting the optical path marked with fluorescent dye markers within the optical data, wherein the method further comprises at least partially determining the turf grain data using the optical path.

33. The method of claim 1, wherein artificial turf fibers comprise a magnetic path marked with magnetic markers, wherein the self propelled robot comprises a magnetic sensor configured for determining the magnetic path marked with the magnetic markers, wherein the method further comprises at least partially determining the turf grain data using the magnetic path.

34-35. (canceled)

36. A turf maintenance robot configured for brushing an artificial turf surface, wherein the turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises: a processor for controlling the turf maintenance robot; and a memory for storing turf grain data descriptive the grain of the artificial turf fibers, wherein the memory further contains machine executable instructions for execution by the processor, wherein execution of the machine executable instructions causes the processor to control the turf maintenance robot to brush the artificial turf fibers dependent upon the turf grain data.

37-42. (canceled)

43. The turf maintenance robot of claim 36, wherein execution of the machine executable instructions further cause the processor to: calculate a cross brushing path using at least partially the turf grain data; and control the turf maintenance robot to follow the cross brushing path.

44-51. (canceled)

52. A turf maintenance system comprising the turf maintenance robot of claim 36, wherein the turf maintenance system of further comprises a drone configured for flying above the artificial turf, wherein the drone comprises a sensor configured for acquiring artificial turf data descriptive of the artificial turf, wherein execution of the machine executable instructions further causes the processor to: control the drone to fly over the artificial turf and acquire the artificial turf data; and control the turf maintenance robot to perform maintenance on the artificial turf using the artificial turf data.

53. The turf maintenance system of claim 52, wherein the artificial turf data comprises image data; wherein execution of the machine executable instructions further cause the processor to: identify at least one maintenance zone within the artificial turf by inputting the image data into an image classification module; and control the turf maintenance robot to perform maintenance on the at least one maintenance zone.

54-55. (canceled)

56. The turf maintenance system of claim 52, wherein the image classification module is configured for identifying the at least one maintenance zone using any one of the following: detecting a color difference in the turf images; detecting a spatially dependent reflectivity of the artificial turf; detecting a pile direction pattern in the turf images; and combinations thereof.

57-58. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0089] In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

[0090] FIG. 1 illustrates an example of an artificial turf;

[0091] FIG. 2 shows a further example of an artificial turf;

[0092] FIG. 3 shows a side view of a turf maintenance robot;

[0093] FIG. 4 shows a top view of the turf maintenance robot of FIG. 3;

[0094] FIG. 5 shows the turf maintenance robot of FIG. 3 in a robot cradle of a robot garage;

[0095] FIG. 6 shows a robot cradle integrated into an autonomous vehicle;

[0096] FIG. 7 illustrates an example of a controller;

[0097] FIG. 8 illustrates a further example of a controller;

[0098] FIG. 9 illustrates a further example of a controller;

[0099] FIG. 10 illustrates a further example of a controller;

[0100] FIG. 11 illustrates a further example of an artificial turf;

[0101] FIG. 12 illustrates a further example of a controller;

[0102] FIG. 13 illustrates a further example of a controller;

[0103] FIG. 14 illustrates a further example of an artificial turf;

[0104] FIG. 15 illustrates a further example of an artificial turf;

[0105] FIG. 16 illustrates a further example of an artificial turf;

[0106] FIG. 17 illustrates a further example of an artificial turf:

[0107] FIG. 18 illustrates an example of a turf maintenance system;

[0108] FIG. 19 shows a flow chart which illustrates an example of a method of operating the turf maintenance system of FIG. 18;

[0109] FIG. 20 illustrates an example of a drone;

[0110] FIG. 21 illustrates an example of a drone surveying an artificial turf; and

[0111] FIG. 22 illustrates the drone of FIG. 21 directing a turf maintenance robot to perform maintenance on the artificial turf.

DETAILED DESCRIPTION

[0112] Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

[0113] FIG. 1 shows a cross-sectional view which illustrates an example of an artificial turf 100. The artificial turf 100 comprises an artificial turf carpet 102. The artificial turf carpet 102 comprises a backing 104 into which artificial turf fibers 106 are tufted or attached. Between the artificial turf fibers 106 is distributed artificial turf infill 108. The artificial turf infill 108 makes the artificial turf 100 seem more soft and shock-absorbent and also serves to help support the artificial turf fibers 106 in a vertical direction. The artificial turf carpet 102 can be seen as being placed on the ground 110. The artificial turf fibers 106 form an artificial turf surface 107. The artificial turf surface 107 is the portion of the artificial turf which is exposed and which a user of the artificial turf 100 would walk or run on.

[0114] When an artificial turf carpet 102 is manufactured the artificial turf fibers 106 are tufted and they may preferentially be tilted at a particular angle. The vector 112 is aligned with the average direction of the artificial turf fibers 106. It can be seen that this is not directly in a vertical position. This is very typical for many artificial turf carpets 102 that are manufactured. The orientation of the vector 112 is the origin of the grain. When the vector 112 is projected into the plane of the backing 104 it results in a vector that travels in a horizontal direction. For the vector 112 the vector 114 indicates the rough direction of the grain. When viewed from above the artificial turf fibers 106 look like they are lying in the direction 114. Direction 116 is the cross-brushing direction 116. Vector 116 is directly opposed to the vector 114 or the grain direction. Brushing the artificial turf fibers 106 in the cross-brushing direction 116 helps the artificial turf fibers 106 to become more vertical and assume a more realistic behavior when compared to real grass.

[0115] FIG. 2 shows an example of an artificial turf 100. The artificial turf 100 may for example be a soccer field or other playing surface. When natural turfs are cut with a lawn mower they are typically done in paths using the lawn mower. This may lead to a lawn that has different regions of uniform appearance. To copy this often times when artificial turfs are installed the artificial turf carpet is installed in sections with the grain of the artificial turf carpet arranged in different directions. FIG. 2 illustrates an artificial turf 100 that has been installed in such a way. There are regions 200 which have the grain going in the direction indicated by the arrow 200 and regions 202 which have the grain going in the opposing direction indicated by the arrow 202.

[0116] To effectively maintain or clean the artificial turf 100 the turf maintenance robot preferably knows which direction to brush the artificial turf in which region. In the regions labeled 200 the artificial turf would be preferentially brushed in the direction opposite of the arrow 200. In the regions 202 the artificial turf would be preferentially brushed opposite to the direction of the arrow 202. Over extended use the grain of the artificial turf may also change. It may therefore be beneficial as time occurs to update or modify turf grain data to better reflect the actual spatial dependence of the grain within the artificial turf 100.

[0117] FIGS. 3 and 4 illustrate an example of a turf maintenance robot 300. FIG. 3 shows a side view and FIG. 4 shows a top view. Both are views of the same robot. The robot 300 is shown as having two drive wheels 302. The drive wheels 302 in this example also comprise a battery or batteries which are integrated into the drive wheels 302. There is also a single front steering wheel 304 that is used to control the direction of travel of the turf maintenance robot 300. The turf maintenance robot has a front 306 and a back or rear 308. The robot 300 is designed such that it travels in the direction of going with the front 306 forward. The drive wheels 302 rotate about a common rotational axis 310. Behind the common rotational axis 310 is located a brush 312. The brush 312 is connected to the turf maintenance robot 300 by a brush height adjustment mechanism 314.

[0118] The brush 312 is mostly located closer to the back or rear 308 than the common rotational axis 310. Between the steering wheel 304 and the two drive wheels 302 is located an inlet nozzle 316. The inlet nozzle 316 is an inlet for a vacuum system. The vacuum system is formed by a garbage container 318, a blower 320, and an exhaust 322. The inlet nozzle 316 is used to remove garbage or debris from the artificial turf before it is prepared or brushed using the brush 312. Between the nozzle 316 and the brush 312 are located a number of turf infill ploughing structures 324. The turf infill ploughing structures may also be referred to as rakes. The turf infill ploughing structures 324 are used to break up and loosen the artificial turf infill before it is brushed. The turf infill ploughing structures 324 are connected to the turf maintenance robot 300 by a number of ploughing structure height adjustment mechanisms 326. As the robot 300 travels forward the artificial turf is first vacuumed using the inlet nozzle 316.

[0119] The artificial turf infill is then roughly dispersed using a turf infill ploughing structure 324. This loosens and may cause the artificial turf infill to be less densely packed. Then finally the artificial turf infill is smoothed and put into position using the brush 312. The brush 312 also may have the effect of making the artificial turf fibers 106 stand up more straight. The entire robot 300 is shown as being covered with a plastic chassis 328. The turf maintenance robot 300 is also shown as comprising a charging socket 330 and a GPS antenna 332. The GPS antenna 332 may also be replaced by other antennas used for receiving different sorts of radio signals for either data exchange and/or positioning. A controller 334 is additionally visible in FIG. 4.

[0120] The example illustrated in FIGS. 3 and 4 is only one example. The example in FIGS. 3 and 4 uses a fixed or stationary brush 312. Other examples may use a rotating brush.

[0121] The robot illustrated in FIGS. 3 and 4 may have several advantages. The use of the stationary brush and the batteries may provide for a robot that may move at approximately 4 km per hour and would take about five hours for it to maintain a typical artificial turf in the form of a football or soccer field.

[0122] The robot 300 has dimensions of typically about 100 cm wide, 115 cm long and about 54 cm high and would weigh about 100 kg.

[0123] The robot in FIG. 3 is shown as optionally comprising a magnetic metal removal component 340. The robot may for example may a permanent magnet or electro magnet that is mounted such that it is able to attract metal fragments that are present in the turf. This may have the benefit of being able to remove ferromagnetic fragments from the turf. In the case of an electromagnet, the electromagnet could be turned off when it is desired to remove and collected metal fragments. If a permanent magnet is used, the permanent magnet could be removable to facilitate removal of any collected metal fragments.

[0124] The robot in FIG. 3 is shown as optionally comprising a grass cutting element 342. A rotating blade or other cutting surface may be incorporated into the robot 300 that is able to cut grass plants to a predetermined height or an adjustable height. This may be useful for cutting grass plans (mowing) that are part of a hybrid turf surface or a natural turf surface. The grass cutting element may in some examples also be able to be selectively turned on and off. This may enable, for example, turning the grass cutting element off when the robot is being used on an artificial turf surface. If the robot is then used over a natural turf or a hybrid turf the grass cutting element can be turned on.

[0125] The robot in FIG. 3 is shown as optionally comprising a grass watering component 344. The grass watering component may for example incorporate a nozzle that is connected to a reservoir or to a hose. This may enable to grass watering element to spray water onto the surface of the turf. This may be useful for watering natural grass plants that are incorporated into artificial turfs or natural turfs. It may also be useful for wetting the surface of an artificial turf before it is used. The spraying of water may for example be used to help prevent the artificial turf from overheating.

[0126] FIG. 5 shows an example of a robot cradle or garage 500. The robot cradle 500 comprises a secondary vacuum 502 for emptying rubbish or garbage from the turf maintenance robot 300. This is deposited in an external garbage container 504. The robot cradle 500 also comprises a charger 506 for automatically charging the turf maintenance robot 300. The robot cradle 500 also has an automatic door 508 which is able to secure or lock the turf maintenance robot 300 securely within the robot cradle 500. This may help prevent damage or theft to the turf maintenance robot 300. It can be seen that the turf maintenance robot 300 must both enter and exit through the automatic door 508. The turf maintenance robot can therefore go either forwards or backwards. The front 306 and back 308 defined in FIG. 3 or 4 is the direction that the turf maintenance robot 300 travels when it is in the process of brushing or cleaning the artificial turf.

[0127] The robot cradle 500 may also be located or incorporated into an autonomous vehicle 600. For example the robot cradle 500 could be mounted on the back of a self-driving car or truck. In this example a ramp 602 provides access to the robot cradle 500. The turf maintenance robot 300 is able to drive and enter the autonomous vehicle 600 and be driven from location to location. This may be beneficial because the turf maintenance robot 300 can have its garbage removed and also be charged when it is being brought automatically between different artificial turfs. This may save time and may result in more efficient use of the turf maintenance robot 300.

[0128] FIG. 7 shows an example of the controller 334 of the turf maintenance robot 300. The controller 334 comprises a hardware interface connected to a processor 702. The hardware interface 700 enables the processor 702 to control the operation and function of the turf maintenance robot 300. It allows it to control such things as the steering wheel 304, the drive wheels 302 and the blower 320 of the vacuum system. The processor 702 is also shown as being connected to a memory 704 and a positioning system 706. The positioning system 706 may comprise one or more of a triangulation system for cell power data, a GPS receiver, a Galileo receiver, a Glonass receiver, and/or a radio system for determining the location from beacons or markers placed in or around the artificial turf. The positioning system 706 is not present in all examples. The memory 704 is shown as containing machine-executable instructions 708.

[0129] Execution of the machine-executable instructions 708 by the processor 702 enables the processor 702 to control and operate the turf maintenance robot 300. The memory 704 is further shown as containing turf grain data 710. The turf grain data 710 contains data which indicates the spatial location of the grain of the artificial turf. The memory 704 is shown as optionally containing a cross brushing path 712. The cross brushing path 712 is a path which the turf maintenance robot 300 will follow such that it directly opposes the grain of the turf. In any case the turf grain data 710 enables the machine-executable instructions 708 to brush the artificial turf surface using the artificial turf maintenance robot 300. The artificial turf maintenance robot performs the brushing dependent upon the turf grain data 710.

[0130] FIG. 8 shows a modification of the controller 334 of FIG. 7. In FIG. 8 the controller 334 further comprises a transceiver 800. The transceiver 800 enables the processor 702 to communicate to a remote server 802. The transceiver 800 for example may be a radio transceiver, a cell transceiver, a Wi-Fi system or other system which enables the processor 702 to communicate with a remote server 802. The memory 704 is shown as optionally containing a database query 804. The database query may be used to query a database located in the remote server 802. The turf grain data 710 may be at least partially in response to the database query 804. For example the turf grain data 710 could be sent to the processor 702 which then stores it in the memory 704.

[0131] The memory 704 is further shown as containing usage data 806 which may be stored by a usage meter. The usage meter may for example be a hardware component or it may be a program or sub-program which is run by the processor 702. It may for example record the distance and/or time usage of the turf maintenance robot. The usage data 806 may for example be used to generate repair instructions 808 and/or billing data such as an invoice either locally by the processor 702 or alternatively the usage data 806 may be sent to the remote server 802 and the repair instructions 808 and/or the invoice 810 may be generated there.

[0132] FIG. 9 shows a further modification of the controller 334 of FIG. 7 or 8. In this example the controller 334 is further shown as containing an optical sensor 900. The optical sensor may for example be a camera, a stereo camera, or a combination thereof. The processor 702 is able to acquire the optical data by controlling the optical sensor 900. The optical data 902 is shown as being stored in the memory 704. The processor 702 then performs such things as pattern recognition or uses a machine learning algorithm to at least partially determine the turf grain data 710 from the optical data 902. For example the turf grain data may be received and as the turf maintenance robot 300 operates the optical data 902 is used to adjust the turf grain data 710 to the current conditions of the artificial turf.

[0133] FIG. 10 shows a further modification of the controller 334 of FIG. 8. In this example the controller 334 is shown as being connected to an RFID reader 1000. The RFID reader 1000 is able to read data from RFID data carriers within the artificial turf and receive RFID data 1002 which is shown as being stored in the memory 704. The RFID data 1002 may contain location data which may be used to at least partially generate and position the artificial turf robot 300 and it may also contain local turf data which may be used to at least partially determine the turf grain data 710.

[0134] FIG. 11 shows the artificial turf 100 of FIG. 2. In FIG. 11 the location of the grain is not shown but instead the location of RFID data carriers 1100 is shown. The RFID data carriers 1100 may for example be embedded in the backing 104 of the artificial turf. The RFID data carriers 1100 may be RFID tags or chips which contain data about the position and/or the turf grain direction in the vicinity of the RFID data carrier 1100. This may be used for positioning the turf maintenance robot and/or orienting it so that it brushes or cleans the artificial turf properly.

[0135] FIG. 12 shows a modification of the controller 334 of FIG. 9. In this example the optical sensor 900 has been replaced with an optical sensor 900 that is able to detect fluorescence. For example fluorescent dyes or markers could be used in the artificial turf fibers. The optical data 902 could be used to identify a detected path 1200. In the example in FIG. 12 the detected path 1200 may be an optical path. The detected path 1200 is explained later in the context of FIGS. 14, 15 and 16.

[0136] FIG. 13 shows a further modification of the controller 334 of FIG. 8. In this example the controller 334 is further shown as being connected to a magnetic sensor 1300 such as a magnetometer. The magnetic sensor 1300 could for example detect magnetic particles that are embedded in regions of the artificial turf fibers and/or backing of the artificial turf carpet. Magnetic particles or materials may also be located between the artificial turf backing and the ground. The magnetic sensor 1300 is able to detect magnetic detector data 1302 and derive a detected path 1200. In the example of FIG. 13 the detected path 1200 is the detected magnetic path. The guidance of the turf maintenance robot using the detected path 1302 is discussed in the context of FIGS. 14, 15 and 16 also.

[0137] The features of the controllers of FIGS. 7, 8, 9, 10, 12, and 13 may be freely combined with each other.

[0138] FIG. 14 shows a further example of a variant of the artificial turf 100 of FIG. 2. In the example in FIG. 14 there is a boundary path 1400 marked. The boundary path 1400 may for example be indicated with fluorescent materials and/or magnetic particles or materials. This may enable the controller of FIG. 12 or 13 to easily locate the boundary of the artificial turf 100. The location of the boundary 1400 may also enable the turf maintenance robot to better determine its position. This may enable proper brushing of the artificial turf surface by the turf maintenance robot and may also help prevent it from accidentally leaving the artificial turf surface 100.

[0139] FIG. 15 shows a further variant of the artificial turf of FIG. 2. In this example, again there is a boundary path 1400. Instead of bounding the overall artificial turf 100 the boundary path 1400 bounds each of the individual regions 200 and 202 as indicated in FIG. 2. Individual regions with different grains are bounded separately. When the turf maintenance robot crosses a boundary 1400 it then knows that it should adjust its motion to account for the change in the grain of the artificial turf.

[0140] FIG. 16 shows a further variant of the artificial turf of FIG. 100. Again, there are a number of predetermined paths 1600. The predetermined paths 1600 may be indicated with fluorescent and/or magnetic particles or materials. In this instance the predetermined paths 1600 are paths which the turf maintenance robot can follow. By following the predetermined paths 1600 in a particular sequence the turf maintenance robot can identify turf grain data which can be used to brush the artificial turf in the proper direction.

[0141] FIG. 17 shows a further variant of the artificial turf 100 of FIG. 100. In this example, the artificial turf 100 is rectangular. There is a transmitter 1700 at each corner of the artificial turf 100. These transmitters 1700 emit electromagnetic radiation in the form of a radio signal 1702. The radio signal 1702 may be either an analog or digital signal. A turf maintenance robot 300 is on the artificial turf 100. The turf maintenance robot 300 comprises a receiver 1704 uses the radio signals 1702 to determine its location on the artificial turf 100. The transmitters 1700 enable the receiver to function as a positioning system. In some examples the receiver 1704 is part of the transceiver 800 of FIG. 8. The system depicted in FIG. 17 may for example be a UWB positioning system.

[0142] FIG. 18 illustrates an example of a turf maintenance system 1800. In this example the turf maintenance system comprises a computer 1802, a turf maintenance robot 300, and a drone 1806. The computer system 1802 comprises a processor 1808 that is in communication with a hardware interface 1810, a user interface 1812, and a memory 1814.

[0143] It should be noted that the components and software elements present in the computer 1802 could also be distributed between the turf maintenance robot 300 and the drone 1806. The features of the computer 1802 can be freely combined with the features of computer 334.

[0144] The hardware interface 1810 enables communication between the processor 1808 and the turf maintenance robot 300 and the drone 1806. It may for example be a radio communication system or a Wi-Fi system. The user interface 1812 is optional and may provide an operator to control the operation and function of the turf maintenance system 1800.

[0145] The memory 1814 is shown as containing machine-executable instructions 1818 which provide instructions for the processor 1808 which enable it to control the turf maintenance system 1800. The memory 1814 is further shown as containing artificial turf data 1820 that has been acquired by the drone 1806. The memory 1814 is further shown as containing an optional image classification module 1822. The artificial turf data 1820 may for example comprise image data. The image classification module 1822 may take this image data as input. The memory 1814 is further shown as containing the optional location of one or more maintenance zones 1824. The location of the maintenance zone 1824 is the identification of areas that require maintenance by the turf maintenance robot 300. The artificial turf data 1820 or the location of the maintenance zones 1824 may be used for controlling the turf maintenance robot 1804 to perform maintenance on an artificial turf.

[0146] FIG. 19 shows a flowchart which illustrates a method of operating the turf maintenance system 1800. First in step 1900 the processor 1808 controls the drone 1806 to fly over the artificial turf and acquire the artificial turf data 1820. Next in step 1902 the processor 1808 controls the turf maintenance robot 1804 to perform maintenance on the artificial turf using the artificial turf data 1820. In some examples the controlling of the artificial turf maintenance robot with the artificial turf data may comprise inputting image data that is part of the artificial turf data into the image classification module 1822 and receiving the location of the maintenance zone 1824 as output.

[0147] FIG. 20 illustrates an example of a drone 1806. The drone comprises a sensor 2000. The sensor 2000 is configured for acquiring the artificial turf data as the drone 1806 overflies the artificial turf.

[0148] FIG. 21 shows an artificial turf 100. In this example the artificial turf is a soccer or football field. The artificial turf 100 could be fields for other sports also. The drone 1806 is shown as flying over the artificial turf 100 and is acquiring the artificial turf data 1820.

[0149] FIG. 7 shows an additional view of the artificial turf 100 after the drone 1806 has flown over and acquired the artificial turf data 1820. In this example the artificial turf data 1820 comprised image data and the image data was input into the image classification module 1822. The image classification module 1822 then output a number of maintenance zones 1824. The location of these maintenance zones 1824 is shown as being superimposed on the artificial turf 100. The location of these turf maintenance zones 1824 is then used to control the turf maintenance robot 300 to perform maintenance in the turf maintenance zones 1824. In this example there are only several areas and the turf maintenance robot 300 does not need to perform maintenance on the entire artificial turf 100.

[0150] The drone 1806 is shown as hovering and monitoring the turf maintenance robot 300. The drone 1806 could for example be used to control directly the turf maintenance robot 300 and ensure it goes to the maintenance zones 1824. This may for example be useful in an indoor arena where it is not possible to receive a GPS signal. The use of the drone 1806 in this fashion would eliminate the need to provide an additional positioning system for the turf maintenance robot 300. In other examples there may be an external positioning system available to the turf maintenance robot 300 such as a GPS system or other location system. In this case the drone 1806 may simply provide the location of the turf maintenance zones 1824 and then the turf maintenance robot 300 performs maintenance on these zones independent of the drone 1806.

[0151] Various examples may possibly be described by one or more of the following features specified in the following numbered clauses:

[0152] 1. A feature comprising a method of maintaining artificial turf (100) using a turf maintenance robot (300), wherein the artificial turf comprises an artificial turf carpet (102), wherein the artificial turf carpet comprises turf fibers (106) which form an artificial turf surface (107), wherein the artificial turf fibers have a grain (114), wherein the artificial turf comprises artificial turf infill (108) distributed between the artificial turf fibers, wherein the turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises a memory (704) for storing turf grain data (710) descriptive of the grain of the artificial turf fibers, the method comprising brushing the artificial turf surface by the turf maintenance robot, whereby the turf maintenance robot performs the brushing dependent upon the turf grain data.

[0153] 2. The method of clause 1, wherein the turf maintenance robot comprises a positioning system (706) for determining a trajectory of the turf maintenance robot.

[0154] 3. The method of clause 2, wherein the position system is further configured for providing a current location, wherein the turf grain data is spatially dependent, wherein the brushing of the artificial turf surface is at least partially determined by turf grain data and the current location.

[0155] 4. The method of clause 1, wherein the turf maintenance robot comprises a positioning system (706) for determining a current location, wherein the brushing of the artificial turf surface is at least partially determined by the current location.

[0156] 5. The method of clause 4, wherein the positioning system further comprises a receiver (1704), and wherein the receiver is configured for at least partially determining the current location using multiple received radio signals (1702).

[0157] 6. The method of any one of the preceding clauses, wherein the turf maintenance robot further comprises a transceiver (800), wherein the method further comprises receiving at least a portion of the turf grain data via the transceiver, and wherein the method further comprises storing the turf grain data in the memory.

[0158] 7. The method of clause 6, wherein the method further comprises sending a database query (804) via the transceiver, wherein the turf grain data is received via the transceiver in response to the database query.

[0159] 8. The method of any one of the preceding clauses, wherein the turf maintenance robot comprises at least one optical sensor (900) configured for acquiring optical data (902) descriptive of the artificial turf surface within a field of view of the at least one optical sensor, wherein the method further comprises: [0160] acquiring the optical data using the at least one optical sensor; and [0161] using the controller to at least partially determining the turf grain data using the optical data.

[0162] 9. The method of clause 8, wherein the at least one optical sensor comprises any one of the following: a camera, a stereo camera, and combinations thereof.

[0163] 10. The method of clause 9, wherein the controller is configured to use a machine learning algorithm to at least partially determine the turf grain data using the optical data.

[0164] 11. The method of any one of the preceding clauses, wherein the turf maintenance robot comprises a usage meter for recording usage data (806), wherein the usage data comprises any one of the following: a time usage data, distance traveled usage data, and combinations thereof, wherein the method further comprises recording the usage data using the usage meter.

[0165] 12. The method of clause 11, wherein the method further comprises generating an invoice using the usage data.

[0166] 13. The method of clause 11, wherein the method further comprises: [0167] sending the usage data to a remote server (802) or cloud storage device; [0168] generating a billing invoice using the usage data by the remote server or the cloud storage device.

[0169] 14. The method of clause 11, 12, or 13, wherein the method further comprises generating repair instructions using at least partially the usage data.

[0170] 15. The method of any one of the preceding clauses, wherein the turf maintenance robot further comprises at least two drive wheels (302) configured for propelling the self propelled robot, wherein the at least two drive wheels have a common rotational axis (310), wherein a brush (312) is mounted at least partially behind the rotational axis, and wherein the brush is mounted between the two drive wheels.

[0171] 16. The method of any one of the preceding clauses, wherein the turf maintenance robot comprises a vacuum system configured for vacuuming the artificial turf surface, wherein the method further comprises vacuuming the artificial turf surface during the brushing of the artificial turf surface.

[0172] 17. The method of clause 16, wherein the vacuum system comprises an inlet nozzle (316) is configured for contacting the artificial turf surface in front of the brush.

[0173] 18. The method of any one of the preceding clause, wherein the turf maintenance robot further comprises turf infill plowing structures (324) in front of the brush.

[0174] 19. The method of clause 18, wherein the turf infill plowing structures comprise a plowing structure height adjustment mechanism (326).

[0175] 20. The method of any one of the preceding clauses, wherein the turf maintenance robot comprises a brush height adjustment mechanism (314) for adjusting the brush height.

[0176] 21. The method of any one of the preceding clauses, wherein the brushing of the artificial turf surface comprises: [0177] calculating a cross brushing path (712) using at least partially the turf grain data; and [0178] controlling the turf maintenance robot to follow the cross brushing path.

[0179] 22. The method of any one of the preceding clauses, wherein method further comprises controlling the turf maintenance robot to travel between multiple artificial turf surfaces.

[0180] 23. The method of any one of the preceding clauses, wherein the turf maintenance robot further comprises at least one RFID reader (1000), wherein the method further comprises at least partially determining the turf grain data using the at least one RFID reader.

[0181] 24. The method of clause 23, wherein the artificial turf comprises an artificial turf carpet with a backing (104), wherein the backing comprises RFID data carriers (1100), wherein the RFID data carriers contain local turf data, wherein the local turf data at least partially comprises the turf grain data, wherein the controller is configured for at least partially receiving the turf grain data from the RFID data carriers by reading the local turf data from the RFID data carriers with the at least one RFID reader.

[0182] 25. The method of any one of the preceding clauses, wherein artificial turf fibers comprise an optical path (1200) marked with fluorescent dye markers, wherein the self propelled robot comprises at least one optical sensor (900) configured for acquiring optical data descriptive of the artificial turf surface within a field of view of the at least one optical sensor, wherein the controller is configured for detecting the optical path marked with fluorescent dye markers within the optical data, wherein the method further comprises at least partially determining the turf grain data using the optical path.

[0183] 26. The method of any one of the preceding clauses, wherein artificial turf fibers comprise a magnetic path (1200) marked with magnetic markers, wherein the self propelled robot comprises a magnetic sensor (1300) configured for determining the magnetic path marked with the magnetic markers, wherein the method further comprises at least partially determining the turf grain data using the magnetic path.

[0184] 27. The method of any one of the preceding clauses, wherein the method further comprises automatically moving the turf maintenance robot between different artificial turf surfaces using an autonomous vehicle.

[0185] 28. The method clause 27, wherein the method further comprises moving the turf maintenance robot using an autonomous vehicle, wherein the autonomous vehicle comprise a robot cradle (500) for holding the turf maintenance robot during travel, and wherein the robot cradle is further configured for charging the turf maintenance robot.

[0186] 29. A feature comprising a turf maintenance robot (300) configured for brushing an artificial turf surface, wherein the turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises: [0187] a processor (702) for controlling the turf maintenance robot; and [0188] a memory (704) for storing turf grain data (710) descriptive the grain of the artificial turf fibers, wherein the memory further contains machine executable instructions (708) for execution by the processor, wherein execution of the machine executable instructions causes the processor to control the turf maintenance robot to brush the artificial turf fibers dependent upon the turf grain data.

[0189] 30. The turf maintenance robot of clause 29, wherein the turf maintenance robot further comprises at least two drive wheels (302) configured for propelling the self propelled robot, wherein the at least two drive wheels have a common rotational axis (310), wherein a brush (312) is mounted at least partially behind the rotational axis, and wherein the brush is mounted between the two drive wheels.

[0190] 31. The turf maintenance robot of clause 30, wherein the turf maintenance robot comprises a vacuum system configured for vacuuming the artificial turf surface, wherein the method further comprises vacuuming the artificial turf surface during the brushing of the artificial turf surface.

[0191] 32. The turf maintenance robot of clause 31, wherein the vacuum system comprises an inlet nozzle (316) is configured for contacting the artificial turf surface in front of the brush.

[0192] 33. The turf maintenance robot of any one of clauses 29 to 32, wherein the turf maintenance robot further comprises turf infill plowing structures (324) in front of the brush.

[0193] 34. The turf maintenance robot of clause 33, wherein the turf infill plowing structures comprise a plowing structure height adjustment mechanism (326).

[0194] 35. The turf maintenance robot of any one of clauses 29 to 34, wherein the turf maintenance robot comprises a brush height adjustment mechanism (314) for adjusting the brush height.

[0195] 36. The turf maintenance robot of any one of clauses 29 to 35, wherein execution of the machine executable instructions further cause the processor to: [0196] calculate a cross brushing path (712) using at least partially the turf grain data; and [0197] control the turf maintenance robot to follow the cross brushing path.

[0198] 37. A feature comprising a turf maintenance robot (300) configured for brushing an artificial turf surface, wherein the turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises: [0199] two drive wheels (302) configured for propelling the self propelled robot, wherein the at least two drive wheels have a common rotational axis (310); and [0200] a stationary brush (312) is mounted at least partially behind the rotational axis, and wherein the stationary brush is mounted between the two drive wheels.

[0201] 38. The turf maintenance robot of clause 37, wherein the turf maintenance robot further comprises: [0202] a processor (702) for controlling the turf maintenance robot; and [0203] a memory (704) for storing turf grain data (710) descriptive the grain of the artificial turf fibers, wherein the memory further contains machine executable instructions (708) for execution by the processor, wherein execution of the machine executable instructions causes the processor to control the turf maintenance robot to brush the artificial turf fibers dependent upon the turf grain data.

[0204] 39. The turf maintenance robot of clause 38, wherein the turf maintenance robot comprises a vacuum system configured for vacuuming the artificial turf surface, wherein the method further comprises vacuuming the artificial turf surface during the brushing of the artificial turf surface, wherein the vacuum system comprises an inlet nozzle is configured for contacting the artificial turf surface in front of the brush

[0205] 40. The turf maintenance robot of any one of clauses 29 to 39, wherein the turf maintenance robot further comprises a grass cutting element (342).

[0206] 41. The turf maintenance robot of any one of clauses 29 to 40, wherein the turf maintenance robot further comprises a grass watering component (344).

[0207] 42. The turf maintenance robot of any one of clauses 29 to 41, wherein the turf maintenance robot further comprises a magnetic metal removal component (340).

[0208] 43. The turf maintenance robot of any one of clauses 29 to 42, wherein the turf maintenance robot comprises a positioning system (706) for providing a current location to the processor (702), wherein the processor is configured for self driving the turf maintenance robot at least partially using the current location.

[0209] 44. A feature comprising a turf maintenance robot (300) configured for brushing an artificial turf surface, wherein the turf maintenance robot is a self driving robot, wherein the turf maintenance robot comprises: [0210] a wireless network interface configured for connecting to a cloud server; [0211] a processor (702) for controlling the turf maintenance robot; and [0212] a memory containing machine executable instructions (708) for execution by the processor, wherein execution of the machine executable instructions causes the processor to: [0213] connect to the cloud server; [0214] receive turf maintenance data from the cloud server; and [0215] control the turf maintenance robot to brush the artificial turf fibers at least partially using the turf maintenance data.

LIST OF REFERENCE NUMERALS

[0216] 100 artificial turf [0217] 102 artificial turf carpet [0218] 104 backing [0219] 106 artificial turf fibers [0220] 107 artificial turf surface [0221] 108 artificial turf infill [0222] 110 ground [0223] 112 average direction of artificial turf fibers [0224] 114 grain direction [0225] 116 cross brushing direction [0226] 200 first direction of grain [0227] 202 second direction of grain [0228] 300 turf maintenance robot [0229] 302 drive wheel [0230] 304 steering wheel [0231] 306 front [0232] 308 back or rear [0233] 310 common rotational axis [0234] 312 brush [0235] 314 brush height adjustment mechanism [0236] 316 inlet nozzle [0237] 318 garbage container [0238] 320 blower [0239] 322 exhaust [0240] 324 turf infill plowing structure [0241] 326 plowing structure height adjustment mechanism [0242] 328 plastic chassis [0243] 330 charging socket [0244] 332 GPS antenna [0245] 334 controller [0246] 340 magnetic metal removal component [0247] 342 grass cutting element [0248] 344 grass watering component [0249] 500 robot cradle or garage [0250] 502 secondary vacuum [0251] 504 garbage container [0252] 506 charger [0253] 508 automatic door [0254] 600 autonomous vehicle [0255] 602 ramp [0256] 700 hardware interface [0257] 702 processor [0258] 704 memory [0259] 706 positioning system [0260] 708 machine executable instructions [0261] 710 turf grain data [0262] 712 cross brushing path [0263] 800 transceiver [0264] 802 remote server [0265] 804 database query [0266] 806 usage data [0267] 808 repair instructions [0268] 810 invoice [0269] 900 optical sensor [0270] 900 optical sensor [0271] 902 optical data [0272] 1000 RFID reader [0273] 1002 RFID data [0274] 1100 RFID data carrier [0275] 1200 detected path [0276] 1300 magnetic sensor [0277] 1302 magnetic detector data [0278] 1400 boundary path [0279] 1600 predetermined path [0280] 1700 transmitter [0281] 1702 radio signal [0282] 1704 receiver [0283] 1800 turf maintenance system [0284] 1802 computer [0285] 1806 drone [0286] 1808 processor [0287] 1810 hardware interface [0288] 1812 user interface [0289] 1814 memory [0290] 1818 machine executable instructions [0291] 1820 artificial turf data [0292] 1822 image classification module [0293] 1824 location of maintenance zone [0294] 1900 control the drone to fly over the artificial turf and acquire the artificial turf data [0295] 1902 control the turf maintenance robot to perform maintenance on the artificial turf using the artificial turf data [0296] 2000 sensor