SE545376C2

SE545376C2 - Navigation for a robotic work tool system

Info

Publication number: SE545376C2
Application number: SE2151251A
Authority: SE
Inventors: Abdelbaki Bougerra; Carl Saxén; Jonathan Andersson; Malin Berger
Original assignee: Husqvarna Ab
Priority date: 2021-10-12
Filing date: 2021-10-12
Publication date: 2023-07-25
Also published as: DE102022126371A1; SE2151251A1

Abstract

A method for use in a robotic work tool (100), wherein the method comprises: establishing a connection with a server (240); receiving an escape route from the server via the communication interface (115); determining that the connection with the server (240) is broken, and in response thereto navigate to a safe zone according to the escape route in order to minimize the risk of erroneous operation when server connection is lost.

Description

NAVIGATION FOR A ROB OTIC WORK TOOL SYSTEM TECHNICAL FIELD This application relates to a robotic Work tool and in particular to a system and a method for providing an improved navigation for robotic Work tools, such as laWnmoWers, in such a system.

BACKGROUND Automated or robotic Work tools such as robotic laWnmoWers are becoming increasingly more popular and so is the use of the same robotic Working tool(s) in more than one Work area. The use of more and more advanced navigation methods are being utilized as Well as command structures based on server communication. More and more robotic Work tools are thus becoming more and more reliant on connection With a server. As there may be many instances When the connection to a server is lost, the robotic Work tools may be rendered inoperable and possibly vulnerable if the connection to the server is lost.

The patent application published as US 2020/0379469 Al discloses a system Where a movable object (referred to as "it") handles a server failure. The disclosure states that it efficiently performs a Work inside a Working region. It includes a historical information storage section to store historical information indicating Work history of a Work machine, and a path plan section to plan a retum path to a retum destination or a return region of a Work machine When a remaining level of an electric storage section satisfies a predeterrnined first condition. The path plan section may refer to historical information stored in the historical information storage section and plan the retum path such that, When a first path including a path included in a Work history and the return path are compared, a distance or area of an overlapping portion between the retum path and the path included in the history of the Work is small.

Thus, there is a need for an improved manner of enabling a robotic Working tool to remain safe even When the connection to the server is broken.

SUMMARY It is therefore an object of the teachings of this application to overcome or at least reduce those problems by providing by providing a robotic Work tool comprising: a controller, a communication interface and a memory; Wherein the controller is configured to: establish a connection With a server; receive an escape route from the server via the communication interface; determine that the connection With the server is broken, and in response thereto navigate to a station location according to the escape route.

The controller is further configured to: Wait for a time period and then attempt to reconnect With the server prior to navigating to the safe zone, and if the reconnection is successful, continue operation, and if the reconnection is unsuccessful, navigating to the safe zone.

The controller is further configured to: attempt to reconnect With the server via a second robotic Work tool.

In some embodiments the time period is less than 5 seconds.

In some embodiments the controller is further configured to: determine that a reconnection With the server is successful during navigation of the escape route, and in response thereto resume operation.

In some embodiments the controller is further configured to resume operation by initiating a new operation task.

In some embodiments the escape route received from the server upon start-up of the robotic Work tool.

In some embodiments the escape route received from the server upon initiation of a Work task.

In some embodiments the escape route received from the server as part of a status message.

In some embodiments the escape route received from the server as part of a command message.

In some embodiments the escape route received from the server at regular intervals.

In some embodiments the controller is further configured to detect an event and in response thereto receive the escape route.

In some embodiments the escape route received includes a return path to be navigated.

In some embodiments the escape route received includes a maximum speed to be utilized.

In some embodiments the escape route received includes timing information for a location to be reached.

In some embodiments the escape route received includes information of another robotic Work tool.

In some embodiments the controller is further configured to navigate according to the escape route and the information of the another robotic Work tool so as to avoid a collision.

In some embodiments the controller is further configured to store a route travelled to the station location as an escape route.

In some embodiments the robotic Work tool is a robotic laWnmoWer.

It is also an object of the teachings of this application to overcome the problems by providing a method for use in a robotic Work tool, Wherein the method comprises: establishing a connection With a server; receiving an escape route from the server via the communication interface; determining that the connection With the server is broken, and in response thereto navigate to a station location according to the escape route.

It is also an object of the teachings of this application to overcome the problems by providing a robotic Work tool system comprising a robotic Work tool according to herein.

In some embodiments the robotic Work tool system comprises a server.

It is also an object of the teachings of this application to overcome the problems by providing a method for use in robotic Work tool system according to herein.

Other features and advantages of the disclosed embodiments Will appear from the following detailed disclosure, from the attached dependent claims as Well as from the draWings. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless eXplicitly defined otherwise herein.

All references to "a/an/the [element, device, component, means, step, etc.]" are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in further detail under reference to the accompanying drawings in which: Figure 1A shows an example of a robotic lawnmower according to some embodiments of the teachings herein; Figure 1B shows a schematic view of the components of an example of a robotic work tool being a robotic lawnmower according to some example embodiments of the teachings herein; Figure 2A shows a schematic view of a robotic work tool system according to some example embodiments of the teachings herein; Figure 2B shows a schematic view of a robotic work tool system according to some example embodiments of the teachings herein; and Figure 3 shows a corresponding ﬂowchart for a method according to some example embodiments of the teachings herein.

DETAILED DESCRIPTION The disclosed embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Like reference numbers refer to like elements throughout.

It should be noted that even though the description given herein will be focused on robotic lawnmowers, the teachings herein may also be applied to, robotic ball collectors, robotic mine sweepers, robotic farming equipment, or other robotic work tools where a work tool is to be safeguarded against from accidentally extending beyond or too close to the edge of the robotic work tool.

Figure 1A shows a perspective view of a robotic work tool 100, here exemplified by a robotic lawnmower 100, having a body 140 and a plurality of wheels 130 (only one side is shown). The robotic work tool 100 may be a multi-chassis type or a mono-chassis type (as in figure 1A). A multi-chassis type comprises more than one main body parts that are movable with respect to one another. A mono-chassis type comprises only one main body part.

It should be noted that robotic lawnmower may be of different sizes, where the size ranges from merely a few decimetres for small garden robots, to almost 1 meters for large robots arranged to service for example airfields.

It should be noted that even though the description herein is focussed on the example of a robotic lawnmower, the teachings may equally be applied to other types of robotic work tools, such as robotic watering tools, robotic golfball collectors, robotic mulchers to mention a few examples.

It should also be noted that the robotic work tool is a self-propelled robotic work tool, capable of autonomous navigation within a work area, where the robotic work tool propels itself across or around the work area in a pattem (random or predetermined).

Figure 1B shows a schematic overview of the robotic work tool 100, also exemplified here by a robotic lawnmower 100. In this example embodiment the robotic lawnmower 100 is of a mono-chassis type, having a main body part 140. The main body part 140 substantially houses all components of the robotic lawnmower 100. The robotic lawnmower 100 has a plurality of wheels 130. In the exemplary embodiment of figure 1B the robotic lawnmower 100 has four wheels 130, two front wheels and two rear wheels. At least some of the wheels 130 are drivably connected to at least one electric motor 150. It should be noted that even if the description herein is focused on electric motors, combustion engines may altematively be used, possibly in combination with an electric motor. In the example of figure lB, each of the wheels 130 is connected to a common or to a respective electric motor 155 for driving the wheels 130 to navigate the robotic lawnmower 100 in different manners. The wheels, the motor 155 and possibly the battery 150 are thus examples of components making up a propulsion device. By controlling the motors 150, the propulsion device may be controlled to propel the robotic lawnmower 100 in a desired manner, and the propulsion device will therefore be seen as synonymous with the motor(s) It should be noted that wheels 130 driven by electric motors is only one example of a propulsion system and other variants are possible such as caterpillar tracks.

The robotic lawnmower 100 also comprises a controller 110 and a computer readable storage medium or memory 120. The controller 110 may be implemented using instructions that enable hardware functionality, for example, by using eXecutable computer program instructions in a general-purpose or special-purpose processor that may be stored on the memory 120 to be eXecuted by such a processor. The controller 110 is configured to read instructions from the memory 120 and eXecute these instructions to control the operation of the robotic lawnmower 100 including, but not being limited to, the propulsion and navigation of the robotic lawnmower.

The controller 110 in combination with the electric motor 155 and the wheels 130 forms the base of a navigation system (possibly comprising further components) for the robotic lawnmower, enabling it to be self-propelled as discussed under figure 1A, The controller 110 may be implemented using any suitable, available processor or Programmable Logic Circuit (PLC). The memory 120 may be implemented using any commonly known technology for computer-readable memories such as ROM, FLASH, DDR, or some other memory technology.

The robotic lawnmower 100 is further arranged with a wireless communication interface 115 for communicating with other devices, such as a server, a personal computer, a smartphone, the charging station, and/or other robotic work tools. Examples of such wireless communication devices are Bluetooth®, WiFi® (IEEE802. 1 lb), Global System Mobile (GSM) and LTE (Long Term Evolution), to name a few. The robotic lawnmower 100 may be arranged to communicate with a user equipment 200 as discussed in relation to figure 2 below for providing information regarding status, location, and progress of operation to the user equipment 200 as well as receiving commands or settings from the user equipment 200. Alternatively or additionally, the robotic lawnmower 100 may be arranged to communicate with a server (referencedin figure 2A) for providing information regarding status, location, and progress of operation as Well as receiving commands or settings.

The robotic 1aWnmoWer 100 also comprises a grass cutting device 160, such as a rotating blade 160 driven by a cutter motor 165. The grass cutting device being an example of a Work tool 160 for a robotic Work tool The robotic 1aWnmoWer 100 may further comprise at least one navigation sensor, such as an optical navigation sensor, an ultrasound sensor, a beacon navigation sensor and/or a satellite navigation sensor 185. The optical navigation sensor may be a camera-based sensor and/or a laser-based sensor. The beacon navigation sensor may be a Radio Frequency receiver, such as an Ultra Wide Band (UWB) receiver or sensor, configured to receive signals from a Radio Frequency beacon, such as a UWB beacon. Altematively or additionally, the beacon navigation sensor may be an optical receiver configured to receive signals from an optical beacon. The satellite navigation sensor may be a GPS (Global Positioning System) device or other Global Navigation Satellite System (GNSS) device. ln embodiments, Where the robotic 1aWnmoWer 100 is arranged With a navigation sensor, the magnetic sensors 170 as Will be discussed below are optional. ln embodiments relying (at least partially) on a navigation sensor, the Work area may be specified as a virtual Work area in a map application stored in the memory 120 of the robotic 1aWnmoWer 100. The virtual Work area may be defined by a virtual boundary.

The robotic 1aWnmoWer 100 may also or alternatively comprise deduced reckoning sensors 180. The deduced reckoning sensors may be odometers, accelerometer or other deduced reckoning sensors. In some embodiments, the deduced reckoning sensors are comprised in the propulsion device, Wherein a deduced reckoning navigation may be provided by knowing the current supplied to a motor and the time the current is supplied, Which Will give an indication of the speed and thereby distance for the corresponding Wheel.

For enabling the robotic 1aWnmoWer 100 to navigate With reference to a boundary Wire emitting a magnetic field caused by a control signal transmitted through the boundary Wire, the robotic 1aWnmoWer 100 is, in some embodiments, further configured to have at least one magnetic field sensor 170 arranged to detect the magnetic field and for detecting the boundary Wire and/or for receiving (and possibly also sending) information to/from a signal generator (Will be discussed With reference to figure 1). In some embodiments, the sensors 170 may be connected to the controller 110, possibly via filters and an amplifier, and the controller 110 may be configured to process and evaluate any signals received from the sensors 170. The sensor signals are caused by the magnetic field being generated by the control signal being transn1itted through the boundary Wire. This enables the controller 110 to determine Whether the robotic laWnmoWer 100 is close to or crossing the boundary Wire, or inside or outside an area enclosed by the boundary Wire.

As mentioned above, in some embodiments, the robotic laWnmoWer 100 is in some embodiments arranged to operate according to a map application of the Work area 205 (and possibly the surroundings of the Work area 205) stored in the memory 120 of the robotic laWnmoWer 100. The map application may be generated or supplemented as the robotic laWnmoWer 100 operates or otherwise moves around in the Work area 205. In some embodiments, the map application includes one or more start regions and one or more goal regions for each Work area. In some embodiments, the map application also includes one or more transport areas.

As discussed in the above, the map application is in some embodiments stored in the memory 120 of the robotic Working tool(s) 100. In some embodiments the map application is stored in the server (referenced 240 in figure 2A). ln some embodiments maps are stored both in the memory 120 of the robotic Working tool(s) 100 and in the server, Wherein the maps may be the same maps or show subsets of features of the area.

The robotic Working tool 100 may also comprise additional sensors 190 for enabling operation of the robotic Working tool 100, such as visual sensors (for example a camera), ranging sensors for enabling SLAM-based navigation (Simultaneous Localization and Mapping), moisture sensors, collision sensors, Wheel load sensors to mention a feW sensors.

Figure 2A shoWs a robotic Work tool system 200 in some embodiments. The schematic vieW is not to scale. The robotic Work tool system 200 comprises one or more robotic Work tools 100 according to the teachings herein. It should be noted that the Work area shoWn in figure 2 is simplified for illustrative purposes. The robotic Work tool system comprises a boundary 220 that may be Virtual and/or electro mechanical such as a magnetic field generated by a control signal being transn1itted through a boundary wire, and which magnetic field is sensed by sensor in the robotic work tool The robotic work tool system 200 further comprises a station 210 possibly at a station location. A station location may alternatively or additionally indicate a service station, a parking area or a safe area where the robotic work tool may remain for a time period between or during operation session.

As with figures 1A and lB, the robotic work tool(s) is eXemplified by a robotic lawnmower, whereby the robotic work tool system may be a robotic lawnmower system or a system comprising a combinations of robotic work tools, one being a robotic lawnmower, but the teachings herein may also be applied to other robotic work tools adapted to operate within a work area.

The one or more robotic Working tools 100 of the robotic work tool system 200 are arranged to operate in a first work area 205A and a second work area 205B.

The work area(s) 105 is in this application eXemplified as a garden, but can also be other work areas as would be understood, such as an airfield. As discussed above, the garden may contain a number of obstacles, for example a number of trees, stones, slopes and houses or other structures.

In some embodiments the robotic work tool is arranged or configured to traverse and operate in work areas that are not essentially flat, but contain terrain that is of varying altitude, such as undulating, comprising hills or slopes or such. The ground of such terrain is not flat and it is not straightforward how to determine an angle between a sensor mounted on the robotic work tool and the ground. The robotic work tool is also or altematively arranged or configured to traverse and operate in a work area that contains obstacles that are not easily discerned from the ground. Examples of such are grass or moss covered rocks, roots or other obstacles that are close to ground and of a similar colour or teXture as the ground. The robotic work tool is also or altematively arranged or configured to traverse and operate in a work area that contains obstacles that are overhanging, i.e. obstacles that may not be detectable from the ground up, such as low hanging branches of trees or bushes. Such a garden is thus not simply a ﬂat lawn to be mowed or similar, but a work area of unpredictable structure and characteristics. The work area 205 eXemplified with referenced to figure 2A, may thus be such a non- uniform work area as disclosed in this paragraph that the robotic work tool is arranged to traverse and/or operate in.

As shown in figure 2A, the robotic working tool(s) 100 is arranged to navigate in one or more work areas 205A, 205B, possibly connected by a transport area TA.

The robotic working tool system 200 may altematively or additionally comprise or be arranged to be connected to a server240, such as a cloud service, a cloud server application or a dedicated server 240. The connection to the server 240 may be direct from the robotic working tool 100, direct from a user equipment 250, indirect from the robotic working tool 100 via the charging station, and/or indirect from the robotic working tool 100 via the user equipment As a skilled person Would understand a server, a cloud server or a cloud service may be implemented in a number of ways utilizing one or more controllers 240A and one or more memories 240B that may be grouped in the same server or over a plurality of servers.

In the below several embodiments of how the robotic work tool may be adapted will be disclosed. It should be noted that all embodiments may be combined in any combination providing a combined adaptation of the robotic work tool.

The inventors have realized that an escape route may change depending on the status of the robotic work tool as well as the location of the robotic work tool, and that the same escape route may therefore not be optimal at all locations.

In some embodiments, and as shown in figure 2A, the robotic work tool 200 is configured to establish a connection with the server 440 and to receive an escape route from the server via the communication interface 215. The robotic work tool is further configured to determine that the connection with the server 440 is broken, and in response thereto navigate to a station location according to the escape route ER. In figure 2A, two escape routes are shown; one for the robotic work tool 100 in the first work area, and one for e the robotic work tool 100B in the second work area 205B.

In some embodiments the robotic work tool is further configured to wait for a time period, for example 5, 10, 30, 60, 120 seconds or in any range there in between and ll then attempt to reconnect With the server 240 prior to navigating to the station location, also referred to as the safe zone. If the reconnection is successful, the robotic Work tool continues operation. And, if the reconnection is unsuccessful, the robotic Work tool navigates to the safe zone.

In some embodiments robotic Work tool l00 is further configured to attempt to reconnect With the server 240 via the second robotic Work tool l00B, Which then acts as an intermediary between the server and the robotic Work tool l00. The attempt to reconnect via the second robotic Work tool may be done as the connection is deterrnined to be lost, and/or as the presence of the second robotic Work tool l00B is detected. The reconnection via the second robotic Work tool may thus be done before starting to navigate to the station location and/or during navigation to the station location.

In embodiments, Where the attempt over the second robotic Work tool l00B is performed prior to navigating to the station location, the time period is less than 5 seconds.

As a robotic Work tool may enter an area Where the connection to the server is more preferable or possible, the robotic Work tool is in some embodiments, further configured to determine that a reconnection With the server 240 is successful during navigation of the escape route, and in response thereto resume operation. The robotic Work tool may then, in some embodiments resume operation by continuing on its previous operation, by returning to the same location, from the present location, or from another location in the Work area.

The robotic Work tool may altematively, in some embodiments resume operation by initiating a new operation task. An operation task may include a specific Work area (possibly a sub area), a task to be performed, a pattern to fulfill, a coverage to achieve and/or a timing to be satisfied (time for start and/or for completion).

In some embodiments, the escape route received from the server upon start-up of the robotic Work tool (200). This ensures that the robotic Work tool 200 has an escape route even before leaving the station location and commencing on an operation.

In some embodiments, the escape route received from the server 240 as part of a status message. In some embodiments, the escape route received from the server 240 as part of a command message. In some embodiments, the escape route received from theserver (240) at regular intervals, such as at every 1, 5, 10 minutes or any range there in between, or such as every 5, 10, 50, 100, 500 meters of operation. Such embodiments all enable the robotic work tool to carry a current escape route, while compromising the amount of communication, by trading the amount of communication to the degree of updated escape route.

In some embodiments, the robotic work tool is further configured to detect an event and in response thereto receive the escape route. The robotic work tool may be configured to detect the event and then signal the event to the server and receive a new or updated escape route. Alternatively or additionally, the robotic work tool may receive the updated escape route in response to the server detecting the event, the robotic work tool then detecting the event through the server.

An event may be an error situation of the robotic work tool, whereby the original escape route may not be suitable, or possible.

An event may alternatively or additionally be that a new (sub area of the) work area is entered. This allows for a current escape route to be received for a (sub)work area even before entering it.

An event may alternatively or additionally be that an object (such as an animal, person or vehicle) is detected in the area. An event may alternatively or additionally be that another robotic work tool enters the work area. This allows for the escape route to be updated so that the object or other robotic work tool is avoided, possibly by halting navigation until the object or robotic work tool is no longer present.

In some embodiments, the escape route received includes a return path to be navigated. This enables the robotic work tool to find its way back to the station location by following a trusted and preferably safe path.

In some embodiments, the escape route received includes a maximum speed to be utilized, thereby ensuring that the robotic work tool navigates safely to the station location. The speed may be related to a part of the escape route and/or to the whole escape route.

In some embodiments, the escape route received includes timing information for a location to be reached, such times possibly indicating times when the robotic work tool is to be at different locations including wait times. This allows for coordinatingmultiple robotic work tools and/or objects by ensuring that they do not occupy the same specific location at the same time.

In some embodiments, the escape route received includes information of another robotic work tool 200. This enables the robotic work tool to determine how to navigate the escape route taking into account the another robotic work tool. In some embodiments, the robotic work tool 200 is further configured to navigate according to the escape route and the information of the another robotic work tool so as to avoid a collision. Alternatively or additionally, the robotic work tool is configured to pause until the other robotic work tool has left the area, which can be communicated from the server.

In some embodiments, the robotic work tool is further configured to store a route travelled to the station location as an escape route. The route may be stored by uploading it to the server. This allows for tried and paths, to be used as escape routes. As the route has been travelled successfully before, the chance for a successful navigation is high.

It should be noted that even if the connection with the server is lost, that does not mean that the robotic work tool is incapable of navigating relatively safely, for example using satellite navigation, deduced reckoning and/or utilizing the magnetic sensors Figure 2B shows a simplified view of a robotic work tool system 200 as in figure 2A. In figure 2A it is shown how the robotic work tool 100 is enabled to return to the station location 210 via one escape route when the robotic work tool 100 is at a first position 100:1 and via another escape route when the robotic work tool is at a second location l00:2, the robotic work tool 100 having received an updated escape route some time while moving from the first to the second position.

Figure 3 shows a ﬂowchart for a general method according to herein. The method is for use in a robotic work tool as in figures 1A and lB. The method comprises establishing 310 a connection with a server 240 and receiving 320 an escape route from the server via the communication interface 215. The method comprises the robotic work tool then deterrnining that the connection with the server 240 is broken or lost 330, and in response thereto navigates 340 to a station location according to the escape route.

Claims

1. A robotic Work tool (100) comprising: a controller (110), a communication interface (115) and a memory (120): Wherein the controller (110) is configured to: establish a connection With a server (240): receive an escape route from the server via the communication interface (115): determine that the connection With the server (240) is broken, and in response thereto navigate to a safe zone according to the escape route, Wherein the controller is further configured to: Wait for a time period and then attempt to reconnect With the server prior to navigating to the safe zone, and if the reconnection is successful, continue operation, and if the reconnection is unsuccessful, navigating to the safe zone, and Wherein the controller is further configured to: attempt to reconnect With the server (240) via a second robotic Work tool.

2. The robotic Work tool according to claim 1, Wherein the time period is less than 5 seconds.

3. The robotic Work tool according to any preceding claims, Wherein the controller is further configured to: determine that a reconnection With the server (240) is successful during navigation of the escape route, and in response thereto resume operation.

4. The robotic Work tool according to claim 3, Wherein the controller is further configured to resume operation by initiating a new operation task.

5. The robotic Work tool (100) according to any preceding claim, Wherein the escape route is received from the server upon start-up of the robotic Work tool (100).

6. The robotic Work tool (100) according to any preceding claim, Wherein the escape route is received from the server upon initiation of a Work task.

7. The robotic Work tool (100) according to any preceding claim, Wherein the escape route is received from the server (240) as part of a status message.

8. The robotic Work tool (100) according to any preceding claim, Wherein the escape route is received from the server (240) as part of a command message.

9. The robotic Work tool (100) according to any preceding claim, Wherein the escape route is received from the server (240) at regular intervals.

10. The robotic Work tool according to any preceding claims, Wherein the controller is further configured to detect an event and in response thereto receive the escape route.

11. The robotic Work tool (100) according to any preceding claim, Wherein the escape route received includes a retum path to be navigated.

12. The robotic Work tool (100) according to any preceding claim, Wherein the escape route received includes a maximum speed to be utilized.

13. The robotic Work tool (100) according to any preceding claim, Wherein the escape route received includes timing information for a location to be reached.

14. The robotic Work tool (100) according to any preceding claim, Wherein the escape route received includes information of another robotic Work tool (100).

15. The robotic Work tool (100) according to c1aim 14, Wherein the contro11er is further configured to navigate according to the escape route and the information of the another robotic Work too1 so as to avoid a co11ision.

16. The robotic Work too1 (100) according to any preceding c1aim, Wherein the contro11er is further configured to store a route trave11ed to the safe zone as an escape route.

17. The robotic Work too1 (100) according to any preceding c1aim, Wherein the safe zone is a station 1ocation (210).

18. The robotic Work too1 (100) according to any preceding c1aim, Wherein the robotic Work too1 (100) is a robotic 1aWnmoWer.

19. A robotic Work too1 system (200) comprising a robotic Work too1 (100) according to any preceding c1aim.

20. The robotic Work too1 system (200) according to c1aim 19 further comprising a server (240).

21. A method for use in a robotic Work too1 (100), Wherein the method comprises: estab1ishing a connection With a server (240); receiving an escape route from the server via the communication interface (115); determining that the connection With the server (240) is broken, and in response thereto navigate to a safe zone according to the escape route, Wherein the method further comprises: Waiting for a time period and then attempt to reconnect With the server prior to navigating to the safe zone, and if the reconnection is successful, continue operation, andif the reconnectíon is unsuccessful, navigatíng to the safe zone, and Wherein the method further comprises: attempting to reconnect With the server (240) Via a second robotíc Work tool.