WO2022177486A1

WO2022177486A1 - Robotic work tool assistance in a robotic work tool system

Info

Publication number: WO2022177486A1
Application number: PCT/SE2022/050118
Authority: WO
Inventors: Kent Askenmalm
Original assignee: Husqvarna Ab
Priority date: 2021-02-22
Filing date: 2022-02-03
Publication date: 2022-08-25
Also published as: SE2150184A1; EP4294169A1; SE545454C2

Abstract

The present disclosure relates to a method for a robotic work tool system (220). The method comprises receiving (S100) a request for assistance from a first outdoor robotic work tool (100a) that at present is not operational and acquiring (S200) position data for the first outdoor robotic work tool (100a). The method further comprises controlling (S300) a second outdoor robotic work tool (100b) to move towards the position of the first outdoor robotic work tool (100a), and controlling (S400) the second outdoor robotic work tool (100b) to acquire camera images of the first outdoor robotic work tool (100a) using a camera device (171).

Description

TITLE

Robotic work tool assistance in a robotic work tool system

TECHNICAL FIELD The present disclosure relates to assistance of an outdoor robotic work tool, such as a robotic lawn mower, in a robotic work tool system.

BACKGROUND

Robotic work tools such as for example robotic lawn mowers are becoming increasingly more popular. In a typical deployment a work area, such as a garden, the work area is enclosed by a boundary wire with the purpose of keeping the robotic lawn mower inside the work area. An electric control signal may be transmitted through the boundary wire thereby generating an (electro-) magnetic field emanating from the boundary wire. The robotic work tool is typically arranged with one or more sensors adapted to sense the control signal.

Alternatively, or as a supplement, the robotic lawn mower can be equipped with a navigation system that is adapted for satellite navigation by means of GPS (Global Positioning System) or some other Global Navigation Satellite System (GNSS) system, for example using Real Time Kinematic (RTK). In addition to this, the navigation system can be adapted for navigation by means of a local base station, for example a navigation beacon, that can be housed in a charging station and provide a navigation signal that further increases the navigation accuracy. Sometimes, a user can control the robotic lawn mower by means of a user terminal, for example an application program in a smartphone.

The robotic lawn mower is adapted to cut grass on a user’s lawn automatically and can be charged automatically without intervention of the user, and does not need to be manually managed after being set once. Two or more robotic lawn mowers can be used in larger systems, like golf courses, parks, sport areas and the like, where a number of robotic mowers are working together to mow the lawns.

Sometimes, however, a robotic lawn mower can be stuck or hindered in some way during operation such that its operation is unexpectedly discontinued. This can for example be due to obstacles and surface conditions such as a slope that has become slippery. This needs attendance of a user that has to check the situation for the robotic lawn mower for which operation has been unexpectedly discontinued. It is therefore desired to provide means and a method for an uncomplicated and quick handling of a situation where an outdoor robotic work tool unexpectedly has discontinued its operation.

SUMMARY The object of the present disclosure is to provide means and a method for an uncomplicated and quick handling of a situation where an outdoor robotic work tool unexpectedly has discontinued its operation.

This object is achieved by means of a method for a robotic work tool system, where the method comprises receiving a request for assistance from a first outdoor robotic work tool that at present is not operational and acquiring position data for the first outdoor robotic work tool. The method further comprises controlling a second outdoor robotic work tool to move towards the position of the first outdoor robotic work tool, and controlling the second outdoor robotic work tool to acquire camera images of the first outdoor robotic work tool using a camera device.

In this manner, the second robotic lawn mower can report the situation regarding the first robotic lawn mower, either to an automatic system or to a user that can initiate certain actions.

According to some aspects, the method comprises determining whether an assisting outdoor robotic work tool can assist the first outdoor robotic work tool such that the first outdoor robotic work tool becomes operational. If that is the case, the method comprises controlling the assisting outdoor robotic work tool to assist the first outdoor robotic work tool accordingly.

This means that if is considered safe and possible, the assisting outdoor robotic work tool is controlled to assist the first outdoor robotic work tool to become operational again. According to some aspects, the method comprises sending the camera images to a user terminal, and presenting the camera images to a user via a screen. According to some aspects, the method comprises a user determining whether the assisting outdoor robotic work tool can assist the first outdoor robotic work tool by means of the displayed camera images.

The user can then decide if it seems safe to proceed with some type of action for bringing the first outdoor robotic work tool into operation again.

According to some aspects, the method comprises using the user terminal for controlling the assisting outdoor robotic work tool to assist the first outdoor robotic work tool. This means that the user initiates one or more actions to bring the first outdoor robotic work tool into operation again.

According to some aspects, the method comprises a user determining whether the first outdoor robotic work tool can be restarted. For example, the method comprises using the user terminal for restarting the first outdoor robotic work tool. In this case, the action comprises restarting the first outdoor robotic work tool.

According to some aspects, the method comprises providing instructions to the user terminal. The instructions enable a user to be presented with the camera images, and to control at least the assisting outdoor robotic work tool via the user terminal.

According to some aspects, the instructions enable the user terminal to establish a wireless connection directly with at least one robotic work tool.

According to some aspects, the instructions enable the user terminal to establish a wireless connection with at least one robotic work tool via a remote server.

This means that program instructions, for example being available in the form of a smartphone application program, and “App”, can be downloaded to the user terminal and enable the user terminal to perform the above. According to some aspects, the method comprises the robotic work tool system determining whether an assisting outdoor robotic work tool can assist the first outdoor robotic work tool by means of the acquired camera images.

This means that the computing device is adapted to more or less make its own decisions, and determining what to do based on the acquired camera images.

According to some aspects, the method comprises the robotic work tool system controlling the assisting outdoor robotic work tool to assist the first outdoor robotic work tool. A user may have to approve such actions before being taken, for example via a user terminal if the computing device is a user terminal.

There are many ways open for an assisting outdoor robotic work tool to assist the first outdoor robotic work tool, a few examples are provided in the following.

According to some aspects, the method comprises the assisting outdoor robotic work tool pushing the first outdoor robotic work tool from its present position. According to some aspects, the method comprises the assisting outdoor robotic work tool connecting to the first outdoor robotic work tool and pulling the first outdoor robotic work tool from its present position.

This can for example be performed by the assisting robotic lawn mower that abuts the first robotic lawn mower and where holding means of the assisting robotic lawn mower attaches to the first robotic lawn mower, enabling the assisting robotic lawn mower to tow the first robotic lawn mower away from its position. The holding means can for example be an electromagnet, where the electromagnet magnetically attaches to the first robotic lawn mower upon activation.

According to some aspects, the second outdoor robotic work tool is used as the assisting outdoor robotic work tool. According to some aspects, the method comprises controlling a third outdoor robotic work tool to move towards the position of the first outdoor robotic work tool, and controlling the third outdoor robotic work tool to acquire camera images of the first outdoor robotic work tool and/or the second outdoor robotic work tool using a camera device.

This means that the third outdoor robotic work tool can provide camera images, while the second outdoor robotic work tool constitutes the assisting outdoor robotic work tool. According to some aspects, the method comprises controlling a third outdoor robotic work tool to move towards the position of the first outdoor robotic work tool; and using the third outdoor robotic work tool as the assisting outdoor robotic work tool.

In this case, the second outdoor robotic work tool can provide camera images, while the third outdoor robotic work tool constitutes the assisting outdoor robotic work tool.

The present disclosure also relates to robotic lawn mowers and robotic work tool systems that are associated with above advantages. In particular, it should be noted that the control unit, the user terminal and the remote server, when a remote server is used, can handle different part of the desired functionality. For example, at least partial data regarding the functionality can be stored at either one of the user terminal and the remote server, or at both. BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described more in detail with reference to the appended drawings, where:

Figure 1 A shows a perspective side view of a robotic lawn mower;

Figure 1 B shows a schematic overview of the robotic lawn mower;

Figure 2 schematically illustrates a robotic lawn mower system; Figure 3 schematically illustrates a first robotic lawn mower being approached by a second robotic lawn mower;

Figure 4A schematically illustrates the first robotic lawn mower being pushed by the second robotic lawn mower;

Figure 4B schematically illustrates the first robotic lawn mower being towed by the second robotic lawn mower; Figure 5 schematically illustrates the first robotic lawn mower being approached by a third robotic lawn mower with the second robotic lawn mower standing by;

Figure 6A schematically illustrates the first robotic lawn mower being pushed by the third robotic lawn mower;

Figure 6B schematically illustrates the first robotic lawn mower being towed by the third robotic lawn mower; Figure 7 shows a schematic view of a control unit;

Figure 8 shows a computer program product; and

Figure 9 shows a flowchart for methods according to the present disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings. The different devices, systems, computer programs and methods disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

The terminology used herein is for describing aspects of the disclosure only and is not intended to limit the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be noted that even though the description given herein will be focused on robotic lawn mowers, the teachings herein may also be applied to any type of outdoor robotic work tool, such as for example robotic ball collectors, robotic mine sweepers and robotic farming equipment.

Figure 1 A shows a perspective view of a robotic lawn mower 100 and Figure 1 B shows a schematic overview of the robotic lawn mower 100. The robotic lawn mower 100 is adapted for a forward travelling direction D, has a body 140 and a plurality of wheels 130; in this example the robotic lawnmower 100 has four wheels 130, two front wheels and two rear wheels. The robotic lawn mower 100 comprises a control unit 110 and at least one electric motor 150, where 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 alternatively be used in combination with an electric motor arrangement. The robotic lawn mower 100 may be a multi-chassis type or a mono-chassis type. A multi-chassis type comprises more than one body parts that are movable with respect to one another. A mono-chassis type comprises only one main body part.

In the following, 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 also comprises a grass cutting device 160, such as a rotating blade 160 driven by a cutter motor 165. The robotic lawnmower 100 also has at least one rechargeable electric power source such as a battery 155 for providing power to the electric motor arrangement 150 and/or the cutter motor 165.

With reference also to Figure 2 that illustrates a robotic lawn mower system 250 in a schematic manner, the battery 155 is arranged to be charged by means of received charging current from a charging station 215, received through charging skids 156 or other suitable charging connectors. Inductive charging without galvanic contact, only by means of electric contact, is also conceivable. The battery is generally constituted by a rechargeable electric power source 155 that comprises one or more batteries that can be separately arranged or be arranged in an integrated manner to form a combined battery. It is conceivable that solar panels comprising photovoltaic cells can be used for charging the rechargeable electric power source 155, at least to a certain extent.

Furthermore, according to some aspects, there is a work area 225 that is enclosed by a boundary wire 220 with the purpose of keeping the robotic lawn mower 100 inside the work area 225. An electric control signal may be transmitted through the boundary wire 220 thereby generating a magnetic field emanating from the boundary wire 220. The robotic work tool system 250 comprises a boundary wire signal generator 221 that is connected to the boundary wire 220 and is adapted to handle all signaling to and from the boundary wire 220.

According to some aspects, the robotic lawnmower 100 may further comprise at least one navigation sensor arrangement 175. In one embodiment, the navigation sensor arrangement 175 comprises one or more sensors for deduced navigation. Examples of sensors for deduced reckoning are odometers, accelerometers, gyroscopes, and compasses to mention a few examples. In one embodiment, the navigation sensor arrangement 175 comprises a beacon navigation sensor 189 and/or a satellite navigation sensor 190. 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 or other type of local base station 214 that can be housed in the charging station 215 or at any other suitable location and provide a navigation signal that further increases the navigation accuracy. Such a local base station 214 is normally relatively small, and can be attached to a pole that is inserted into the ground.

The satellite navigation sensor may be a GPS (Global Positioning System) device or other Global Navigation Satellite System (GNSS) device, according to some aspects for example using Real Time Kinematic (RTK).

The robotic lawn mower 100 thus comprises a navigation system 175 that according to some aspects is adapted for satellite navigation and/or navigation by means of one or more local beacons in the form of one or more local base stations. The robotic lawn mower 100 further comprises a control unit 110 adapted to control the operation of the robotic lawn mower 100. The control unit 110 is further adapted to receive position data from the navigation system 175 and instructions from a user terminal 205, said instructions comprising directions for movement of the robotic lawn mower 100.

The navigation system 175 may be used as a complement to the boundary wire 220, or instead of the boundary wire 220. In the latter case, the robotic lawn mower system 250 does not comprise a boundary wire 220. As an alternative, the robotic lawn mower 100 may not comprise a navigation system, and is in that case the robotic lawn mower system 250 does comprise the boundary wire 220.

According to some aspects, to alleviate navigation irrespective of the presence of a boundary wire and/or a navigation system, the robotic lawn mower 100 further comprises at least one environment detection device 170, 171. In this example, radar transceivers 170 are provided where each radar transceiver 170 comprises a corresponding transmitter arrangement and receiver arrangement together with other necessary circuitry in a well-known manner. In this example, the robotic lawn mower 100 further comprises a camera device 171 that is adapted to provide images of the environment in front of the robotic lawn mower 100.

For this purpose, the control unit 110 is adapted to control the camera device 171 and the radar transceivers 170 and to control the speed and direction of the robotic lawn mower 100 in dependence of information acquired by means of the of the radar transceivers 170 when the robotic lawn mower 100 is moving.

According to some aspects, navigation can be made purely or partly by use of landmarks i.e. by means of a camera-based navigation sensor arrangement, possibly together with one or more radar transceivers.

In the following, two or more robotic lawn mowers in the robotic lawn mower system 250 will be described, and these robotic lawn mowers will be of the kind previously described. Previously generally described lawn mower parts such as navigation system, camera and control unit will be conferred the same reference number for the different robotic lawn mowers as in the general description above.

The robotic lawn mower system 250 comprises a first robotic lawn mower 100a comprising a navigation system 175 and a control unit 110 according to the above, where the control unit 110 is adapted to control the operation of the first robotic lawn mower 100. The control unit 110 is further adapted to receive position data from the navigation system 175 and instructions comprising directions for movement of the first robotic lawn mower 100a. The control unit 110 is adapted to control a wireless transmission of present position data for the first robotic lawn mower 100a together with a request for assistance when the control unit 110 has determined that the first robotic lawn mower 100a has become non-operational during operation.

This means that the first robotic lawn mower 100a may be stuck or hindered in some way during operation such that its operation is unexpectedly discontinued. This can for example be due to obstacles and surface conditions such as a slope that has become slippery. When this has happened, the first robotic lawn mower 100a does not continue trying to operate, but transmit a request for assistance together with data regarding its present position.

According to some aspects, the control unit 110 adapted to initiate a restart of the first robotic lawn mower 100a after having received corresponding instructions. Such a restart may have to be manually initiated, and therefore a user has to initiate the restart.

The robotic lawn mower system 250 comprises a further robotic lawn mower 100b that comprises a camera device 171 , a navigation system 175 and a control unit 110 according to the above, where the control unit 110 is adapted to control the operation of the further robotic lawn mower 100b. The control unit 110 is further adapted to receive position data from the navigation system 175 and to receive instructions comprising directions for movement of the further robotic lawn mower 100b. Upon request, the control unit 110 is adapted to control movement of the further robotic lawn mower 100b towards a certain provided position and to provide camera images of a first outdoor robotic work 100a tool by means of the camera device 171. In the following example, the further robotic lawn mower is constituted by a second robotic lawn mower 100b.

The robotic lawn mower system 250 further comprises at least one computing device 205, 207, 208 that is separate from the outdoor robotic lawn mowers 100a, 100b and arranged for wireless communication with the outdoor robotic lawn mowers 100a, 100b. The computing device is for example in the form of a user terminal 205 such as a mobile phone or remote control, a remote server 207 or a local server 208 comprised in the charging station 215.

The computing device 205, 207, 208 is adapted to receive a request for assistance from a first outdoor robotic lawn mower 100a that at present is not operational, and to acquire position data for the first robotic lawn mower 100a. As shown in Figure 2 and Figure 3, the computing device 205, 207, 208 is further adapted to provide instructions to the second robotic lawn mower 100b, which instructions enable the second robotic lawn mower 100b to move towards the position of the first robotic lawn mower 100a, and to provide instructions to the second robotic lawn mower 100b, which instructions enable the second robotic lawn mower 100b to acquire camera images of the first robotic lawn mower 100a using a camera device 171 comprised in the second robotic lawn mower 100b.

The instructions can either be provided automatically, or by means of user input. In the latter case, the user may have been alerted regarded the first outdoor robotic lawn mower 100a not being operational.

In this manner, the second robotic lawn mower 100b can report the situation regarding the first robotic lawn mower 100a, either to an automatic system or to a user that can initiate certain actions. According to some aspects, the second robotic lawn mower 100b is adapted to transmit the camera images to a computing device in the form of user terminal 205 that is adapted to present camera images to a user via a screen 206. The user can then decide if it seems safe to proceed with some type of action for bringing the first robotic lawn mower 100a into operation again. For example, the user can determine that it is safe to restart the first robotic lawn mower 100a by means of the displayed camera images. The user terminal 205 is then adapted to receive user input for controlling the first outdoor robotic lawn mower 100a to restart.

For example, the user can determine that an assisting robotic work lawn mower, in this example the second robotic lawn mower 100b, can assist the first outdoor robotic lawn mower 100a by means of the displayed camera images. The user terminal 205 is then adapted to receive user input for controlling the second robotic lawn mower 100b, to assist the first robotic lawn mower 100a.

According to some aspects, the user terminal 205 is adapted to receive and store instructions, which instructions enable a user to be presented with the camera images, and/or control at least the assisting robotic lawn mower 100b via the user terminal 205, and or control the first outdoor robotic lawn mower 100a to restart.

According to some aspects, the instructions enable the user terminal 205 to establish a wireless connection directly with at least one robotic lawn mower 100a, 100b, 100c. According to some aspects, the instructions enable the user terminal 205 to establish a wireless connection at least one robotic lawn mower 100a, 100b, 100c via a remote server 207.

This means that program instructions, for example being available in the form of a smartphone application program, and “App”, can be downloaded to the user terminal 205 and enable the user terminal 205 to perform the above.

According to some aspects, the computing device 205, 207, 208 is adapted to more or less make its own decisions. For example, the computing device 205, 207, 208 can be adapted to determine whether an assisting robotic lawn mower, such as the second robotic lawn mower 100b, can assist the first outdoor robotic lawn mower 100a such that the first outdoor robotic lawn mower 100a becomes operational. The determining is enabled by means of the acquired camera images. If that is the case, the computing device 205, 207, 208 can be adapted to control the second robotic lawn mower 100b to assist the first outdoor robotic lawn mower 100a accordingly. A user may have to approve such actions before being taken, for example via a user terminal 205 if the computing device is a user terminal.

In case the computing device is a remote server 207, this remote server may be capable of making automatic decision and taking actions automatically. Alternatively, such a remote server 207 may be positioned at a manned central where manual control is enabled, for example in the same manner as in the examples described above for a user and a user terminal. Such a manned central may be connected to several robotic lawn mower system, relieving owners/keepers of these robotic lawn mower system of the work and responsibility related to cases where assistance is requested by a robotic lawn mower.

In any case, the assistance can be performed in several ways. For example, as shown in Figure 4A, the computing device 205, 207, 208 can be adapted to provide instructions to the assisting robotic lawn mower 100b, which instructions enable the assisting robotic lawn mower 100b, 100c to push the first outdoor robotic lawn mower 100a from its present position.

This means that, upon request, the control unit 110 is adapted to control movement of the assisting robotic lawn mower 100b to abut the first robotic lawn mower 100a and to push the first robotic lawn mower 100a away from its position.

According to some aspects, as shown in Figure 4B, the assisting robotic lawn mower 100b comprises a holding means 410, and the computing device 205, 207, 208 is adapted to provide instructions to the assisting robotic lawn mower 100b. The instructions enable the assisting robotic lawn mower 100b to abut the first robotic lawn mower 100a, to control the holding means 410 to attach to the first robotic lawn mower 100a, and to tow the first robotic lawn mower 100a away from its position.

This means that, upon request, the control unit 110 is adapted to control movement of the assisting robotic lawn mower 100b to abut the first robotic lawn mower 100a, to control the holding means 410 to attach to the first robotic lawn mower 100a, and to tow the first robotic lawn mower 100a away from its position. According to some aspects, the holding means is an electromagnet 410, where the electromagnet magnetically attaches to the first robotic lawn mower 100a upon activation. This means that the control unit 110 of the assisting robotic lawn mower 100b is adapted to activate the electromagnet 410 such that the electromagnet magnetically attaches to the first robotic lawn mower 100a.

According to some aspects, the instructions provided by the computing device 205, 207, 208 include instructions to the first robotic lawn mower 100a to engage its propulsion in the movement direction of the assisting robotic lawn mower 100b, and/or to lift its grass cutting device 160 away from the ground such that movement of the first robotic lawn mower 100a is alleviated.

According to some aspects, the assisting robotic lawn mower 100b is adapted to receive at least one of said requests from a user terminal 205.

According to some aspects, the assisting robotic lawn mower 100b is adapted to receive at least one of said requests from a computing device 207, 208, separate from the assisting robotic lawn mower 100b, by means of wireless communication with said computing device 207, 208.

According to some aspects, the assisting robotic lawn mower 100b is adapted to receive at least one of said requests from a central control function that is manually or automatically operated.

In the above, the assisting robotic lawn mower has been constituted by the second robotic lawn mower 100b.

According to some aspects, with reference to Figure 2 and Figure 5, the robotic work tool system 250 comprises one more further robotic lawn mowers 100c, here there is one further robotic lawn mower constituting a third robotic lawn mower 100c. The computing device 205, 207, 208 is adapted to control the third robotic lawn mower 100c to move towards the position of the first robotic lawn mower 100a and to acquire camera images of the first robotic lawn mower 100a and/or the second robotic lawn mower 100b using a camera device 171. This means that the third robotic lawn mower 100c can provide camera images, while the second robotic lawn mower 100b constitutes the assisting robotic lawn mower as illustrated in Figure 4A and Figure 4B.

According to some aspects, with reference to Figure 2, Figure 6A and Figure 6B, the robotic work tool system 250 comprises one more further robotic lawn mowers 100c, here there is one further robotic lawn mower constituting a third robotic lawn mower 100c, where the third robotic lawn mower 100c, is the assisting robotic lawn mower. In Figure 6A, the third robotic lawn mower 100c pushes the first robotic lawn mower 100a as described above, and in Figure 6B, the third robotic lawn mower 100c tows the first robotic lawn mower 100a as described above. In this case, the second robotic lawn mower 100b can provide camera images, while the third robotic lawn mower 100c constitutes the assisting robotic lawn mower.

Generally, the second robotic lawn mower 100b and the third robotic lawn mower 100c are constituted by further robotic lawn mowers 100b, 100c, of which at least one is comprised in the robotic work tool system 250.

Therefore, according to some aspects, the term “further robotic lawn mower” can be regarded as a generic term that indicates a robotic lawn mower that can constitute a certain type of robotic lawn mower to be defined in different examples.

According to some aspects, all lawn mowers 110a, 110b, 100c comprised in the robotic work tool system 250 are adapted for normal grass cutting, meaning that when no requests for assistance have been issued, all robotic lawn mowers 110a, 110b, 100c, including some or all of the assisting robotic lawn mowers 100b, 100c, may work normally by cutting grass. This means that the assisting robotic lawn mowers 100b, 100c are not only service devices that are put to use only when assistance is required.

According to some aspects, one or more, and even all, robotic lawn mowers 110a, 110b, 100c comprised in the robotic work tool system 250 may be adapted to be assisting robotic lawn mowers 100b, 100c. According to some aspects, the remote computing device is a user terminal 205, a remote server 207 and/or a local server 208 in a charging station 215.

In Figure 7 it is schematically illustrated, in terms of a number of functional units, the components of a computing device 205, 207, 208 according to embodiments of the discussions herein. Processing circuitry 115 is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium 120. The processing circuitry 115 may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA. The processing circuitry thus comprises a plurality of digital logic components.

Particularly, the processing circuitry 115 is configured to cause the computing device 205, 207, 208 to perform a set of operations, or steps to control operation of the robotic lawn mowers 100a, 100b, 100c. For example, the storage medium 120 may store the set of operations, and the processing circuitry 115 may be configured to retrieve the set of operations from the storage medium 120 to cause the computing device 205, 207, 208 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuitry 115 is thereby arranged to execute at least parts of the methods as herein disclosed.

The storage medium 120 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

According to some aspects, the computing device 205, 207, 208 further comprises an interface 112 for communications with at least one external device such as a robotic lawn mowers 100a, 100b, 100c. As such, the interface 112 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline communication. The interface 112 can be adapted for communication with other devices, such as the charging station 215, and/or the robotic lawn mowers 100a, 100b, 100c. Examples of such wireless communication devices are Bluetooth®, WiFi® (IEEE802.11b), Global System Mobile (GSM) and LTE (Long Term Evolution), to name a few.

Figure 8 shows a computer program product 800 comprising computer executable instructions 810 stored on media 820 to execute any of the methods disclosed herein.

With reference to Figure 9, the present disclosure also relates to a method for a robotic work tool system 220. The method comprises receiving S100 a request for assistance from a first outdoor robotic work tool 100a that at present is not operational, and acquiring S200 position data for the first outdoor robotic work tool 100a. The method further comprises controlling S300 a second outdoor robotic work tool 100b to move towards the position of the first outdoor robotic work tool 100a, and controlling S400 the second outdoor robotic work tool 100b to acquire camera images of the first outdoor robotic work tool 100a using a camera device 171.

According to some aspects, the method comprises determining S500 whether an assisting outdoor robotic work tool 100b, 100c can assist the first outdoor robotic work tool 100a such that the first outdoor robotic work tool 100a becomes operational. If that is the case, the method comprises controlling S600 the assisting outdoor robotic work tool 100b, 100c to assist the first outdoor robotic work tool 100a accordingly.

According to some aspects, the method comprises sending S700 the camera images to a user terminal 205, and presenting S800 the camera images to a user via a screen 206.

According to some aspects, the method comprises a user determining whether the assisting outdoor robotic work tool 100b, 100c can assist the first outdoor robotic work tool 100a by means of the displayed camera images. According to some aspects, the method comprises using the user terminal 205 for controlling the assisting outdoor robotic work tool 100b, 100c to assist the first outdoor robotic work tool 100a. According to some aspects, the method comprises a user determining whether the first outdoor robotic work tool 100a can be restarted.

According to some aspects, the method comprises using the user terminal 205 for restarting the first outdoor robotic work tool 100a.

According to some aspects, the method comprises providing instructions to the user terminal 205, which instructions enable a user to be presented with the camera images, and to control at least the assisting outdoor robotic work tool 100b, 100c via the user terminal 205.

According to some aspects, the instructions enable the user terminal 205 to establish a wireless connection directly with at least one robotic work tool 100a, 100b, 100c. According to some aspects, the instructions enable the user terminal to establish a wireless connection with at least one robotic work tool 100a, 100b, 100c via a remote server 207.

According to some aspects, the method comprises the robotic work tool system 220 determining whether an assisting outdoor robotic work tool 100b, 100c can assist the first outdoor robotic work tool 100a by means of the acquired camera images.

According to some aspects, the method comprises the robotic work tool system 220 controlling the assisting outdoor robotic work tool 100b, 100c to assist the first outdoor robotic work tool 100a.

According to some aspects, the method comprises the assisting outdoor robotic work tool 100b, 100c pushing the first outdoor robotic work tool 100a from its present position.

According to some aspects, the method comprises the assisting outdoor robotic work tool 100b, 100c connecting to the first outdoor robotic work tool 100a and pulling the first outdoor robotic work tool 100a from its present position. According to some aspects, the second outdoor robotic work tool 100b is used as the assisting outdoor robotic work tool.

According to some aspects, the method comprises controlling a third outdoor robotic work tool 100c to move towards the position of the first outdoor robotic work tool, and controlling the third outdoor robotic work tool 100c to acquire camera images of the first outdoor robotic work tool 100a and/or the second outdoor robotic work tool 100b using a camera device 171. According to some aspects, the method comprises controlling a third outdoor robotic work tool 100c to move towards the position of the first outdoor robotic work tool, and using the third outdoor robotic work tool 100c as the assisting outdoor robotic work tool. The present disclosure is not limited to the examples above, but may vary freely within the scope of the appended claims. For example, other types of assisting actions are conceivable. For example, the assisting robotic lawn mower can be adapted to charge the first robotic lawn mower if it has been determined that the first robotic lawn mower has run out of battery charge.

The present disclosure is particularly advantageous for robotic lawn mowers and robotic lawn mower systems for a plurality of reasons.

For example, robotic lawn mowers often work on large areas, such as golf courses, parks, sport areas and the like, where a number of robotic lawn mowers are working together to mow one or more lawns. When one robotic lawn mower requires assistance, it is often time-consuming for a person to localize and walk to the robotic lawn mower requiring assistance. By means of the present disclosure, a robotic lawn mower requiring assistance can be handled in an efficient and reliable manner without an operator needing to walk to the robotic lawn mower requiring assistance and perform the required assistance.

Furthermore, the outdoor work of mowing lawns is associated with events such as changing weather where for example heavy rain can produce slippery muddy pools of water, and strong winds may tear of branches from trees. New obstacles such as vehicles, building material and park benches can be deployed, and holes or trenches can be dug. Furthermore, animals can also produce new obstacles, for example molehills. These events are much more common than malfunction of the robotic lawn mower itself, and by means of the present disclosure problems arising from such events can be handled in an efficient and reliable manner.

Sometimes security aspects require that remote actions such as assistance performed by an assisting robotic lawn mower has to be surveilled by an operator. In this case, camera images relayed to an operator constitute a convenient manner to handle such security aspects.

Claims

1. A method for a robotic lawn mower system (220), where the method comprises: receiving (S100) a request for assistance from a first robotic lawn mower

(100a) that at present is not operational; acquiring (S200) position data for the first robotic lawn mower (100a); controlling (S300) a second robotic lawn mower (100b) to move towards the position of the first robotic lawn mower (100a); and controlling (S400) the second robotic lawn mower (100b) to acquire camera images of the first robotic lawn mower (100a) using a camera device (171).

2. The method according to claim 1 , further comprising determining (S500) whether an assisting robotic lawn mower (100b, 100c) can assist the first robotic lawn mower (100a) such that the first robotic lawn mower (100a) becomes operational, and if that is the case, controlling (S600) the assisting robotic lawn mower (100b, 100c) to assist the first robotic lawn mower (100a) accordingly.

3. The method according to any one of the claims 1 or 2, wherein the method comprises sending (S700) the camera images to a user terminal (205), and presenting (S800) the camera images to a user via a screen (206).

4. The method according to claim 3, wherein the method comprises a user determining whether the assisting robotic lawn mower (100b, 100c) can assist the first robotic lawn mower (100a) by means of the displayed camera images.

5. The method according to claim 4, wherein the method comprises using the user terminal (205) for controlling the assisting robotic lawn mower (100b, 100c) to assist the first robotic lawn mower (100a).

6. The method according to claim 3, wherein the method comprises a user determining whether the first robotic lawn mower (100a) can be restarted.

7. The method according to claim 4, wherein the method comprises using the user terminal (205) for restarting the first robotic lawn mower (100a).

8 The method according to any one of the claims 2-7, further comprising providing instructions to the user terminal (205), which instructions enable a user to

- be presented with the camera images; and

- control at least the assisting robotic lawn mower (100b, 100c) via the user terminal (205).

9. The method according to claim 8, wherein the instructions enable the user terminal (205) to establish a wireless connection directly with at least one robotic lawn mower (100a, 100b, 100c).

10. The method according to any one of the claims 8 or 9, wherein the instructions enable the user terminal to establish a wireless connection with at least one robotic lawn mower (100a, 100b, 100c) via a remote server (207).

11. The method according to any one of the claims 2 or 3, wherein the method comprises the robotic lawn mower system (220) determining whether an assisting robotic lawn mower (100b, 100c) can assist the first robotic lawn mower (100a) by means of the acquired camera images.

12. The method according to claim 11, wherein the method comprises the robotic lawn mower system (220) controlling the assisting robotic lawn mower (100b,

100c) to assist the first robotic lawn mower (100a).

13. The method according to any one of the claims 5 or 10, wherein the method comprises the assisting robotic lawn mower (100b, 100c) pushing the first robotic lawn mower (100a) from its present position.

14. The method according to any one of the claims 5 or 12, wherein the method comprises the assisting robotic lawn mower (100b, 100c) connecting to the first robotic lawn mower (100a) and pulling the first robotic lawn mower (100a) from its present position.

15. The method according to any one of the claims 2-14, wherein the second robotic lawn mower (100b) is used as the assisting robotic lawn mower.

16. The method according to any one of the claims 2-15, wherein the method comprises controlling a third robotic lawn mower (100c) to move towards the position of the first robotic lawn mower; and controlling the third robotic lawn mower (100c) to acquire camera images of the first robotic lawn mower (100a) and/or the second robotic lawn mower (100b) using a camera device (171).

17. The method according to any one of the claims 2-14, wherein the method comprises controlling a third robotic lawn mower (100c) to move towards the position of the first robotic lawn mower; and using the third robotic lawn mower (100c) as the assisting robotic lawn mower.

18. A first robotic lawn mower (100a) comprising a navigation system (175) and a control unit (110) adapted to control the operation of the first robotic lawn mower (100), where the control unit (110) further is adapted to receive position data from the navigation system (175) and instructions comprising directions for movement of the first robotic lawn mower (100a), where the control unit (110) is adapted to control a wireless transmission of present position data for the first robotic lawn mower (100a) together with a request for assistance when the control unit (110) has determined that the first robotic lawn mower (100a) has become non-operational during operation.

19. The first robotic lawn mower (100a) according to claim 18, wherein the control unit (110) adapted to initiate a restart of the first robotic lawn mower (100a) after having received corresponding instructions.

20. A further robotic lawn mower (100b, 100c) comprising a camera device (171), a navigation system (175) and a control unit (110) adapted to control the operation of the further robotic lawn mower (100b, 100c), where the control unit (110) further is adapted to receive position data from the navigation system (175) and to receive instructions comprising directions for movement of the further robotic lawn mower (100b, 100c), where, upon request, the control unit (110) is adapted to control movement of the further robotic lawn mower (100b, 100c) towards a certain provided position and to provide camera images of a first robotic lawn mower (100a) by means of the camera device (171).

21. The further robotic lawn mower (100b, 100c) according to claim 20, wherein, upon request, the control unit (110) is adapted to control movement of the further robotic lawn mower (100b, 100c) to abut the first robotic lawn mower (100a) and to push the first robotic lawn mower (100a) away from its position.

22. The further robotic lawn mower (100b, 100c) according to any one of the claims 20 or 21, wherein the further robotic lawn mower (100b, 100c) comprises a holding means (410), where, upon request, the control unit (110) is adapted to control movement of the further robotic lawn mower (100b, 100c) to abut the first robotic lawn mower (100a), to control the holding means (410) to attach to the first robotic lawn mower (100a), and to tow the first robotic lawn mower (100a) away from its position.

23. The further robotic lawn mower (100b, 100c) according to claim 22, wherein the holding means is an electromagnet (410), and where the control unit (110) is adapted to activate the electromagnet (410) such that the electromagnet magnetically attaches to the first robotic lawn mower (100a).

24. The further robotic lawn mower (100b, 100c) according to any one of the claims 20-23, wherein the further robotic lawn mower (100b, 100c) is adapted to receive at least one of said requests from a user terminal (205).

25. The further robotic lawn mower (100b, 100c) according to any one of the claims 20-24, wherein the further robotic lawn mower (100b, 100c) is adapted to receive at least one of said requests from a computing device (207, 208), separate from the further robotic lawn mower (100b, 100c), by means of wireless communication with said computing device (207, 208).

26. The further robotic lawn mower (100b, 100c) according to any one of the claims 20-25, wherein the further robotic lawn mower (100b, 100c) is adapted to receive at least one of said requests from a central control function that is manually or automatically operated..

27. A robotic lawn mower system (250) comprising a first robotic lawn mower (100a) according to any one of the claims 18 and 19, and a further robotic lawn mower (100b) according to any one of the claims 20-26, the further robotic lawn mower constituting a second robotic lawn mower (100b), wherein the robotic lawn mower system (250) further comprises at least one computing device (205, 207, 208) that is separate from the robotic lawn mowers (100a, 100b, 100c) and arranged for wireless communication with the robotic lawn mowers (100a, 100b, 100c), where the computing device (205, 207, 208) is adapted to

- receive a request for assistance from a first robotic lawn mower (100a) that at present is not operational;

- acquire position data for the first robotic lawn mower (100a);

- provide instructions to the second robotic lawn mower (100b), which instructions enable the second robotic lawn mower (100b) to move towards the position of the first robotic lawn mower (100a); and

- provide instructions to the second robotic lawn mower (100b), which instructions enable I the second robotic lawn mower (100b) to acquire camera images of the first robotic lawn mower (100a) using a camera device (171 ) comprised in the second robotic lawn mower (100).

28. The robotic lawn mower system (250) according to claim 27, wherein the second robotic lawn mower (100) is adapted to transmit the camera images to a computing device in the form of user terminal (205) that is adapted to present camera images to a user via a screen (206).

29. The robotic lawn mower system (250) according to claim 28, wherein the user terminal (205) is adapted to receive user input for controlling the first robotic lawn mower (100a) to restart.

30. The robotic lawn mower system (250) according to claim 28, wherein the user terminal (205) is adapted to receive user input for controlling an assisting robotic lawn mower (100b, 100c) to assist the first robotic lawn mower (100a).

31. The robotic lawn mower system (250) according to any one of the claims

27-30, wherein the user terminal (205) is adapted to receive and store instructions, which instructions enable a user to

- be presented with the camera images; and/or

- control at least one assisting robotic lawn mower (100b, 100c) via the user terminal (205), and/or

- control the first robotic lawn mower (100a) to restart..

32. The robotic lawn mower system (250) according to claim 31 , wherein the instructions enable the user terminal (205) to establish a wireless connection directly with at least one robotic lawn mower (100a, 100b, 100c).

33. The robotic lawn mower system (250) according to any one of the claims 31 or 32, wherein the instructions enable the user terminal (205) to establish a wireless connection to at least one robotic lawn mower (100a, 100b, 100c) via a remote server (207).

34. The robotic lawn mower system (250) according to any one of the claims 28 or 29, wherein the computing device (205, 207, 208) is adapted to determine whether an assisting robotic lawn mower (100b, 100c) can assist the first robotic lawn mower (100a) by means of the acquired camera images.

35. The robotic lawn mower system (250) according to claim 34, wherein the computing device (205, 207, 208) is adapted to control the assisting robotic lawn mower (100b, 100c) to assist the first robotic lawn mower (100a).

36. The robotic lawn mower system (250) according to any one of the claims 30 or 35, wherein the computing device (205, 207, 208) is adapted to provide instructions to the assisting robotic lawn mower (100b, 100c), which instructions enable the assisting robotic lawn mower (100b, 100c) to push the first robotic lawn mower (100a) from its present position.

37. The robotic lawn mower system (250) according to any one of the claims 30-36, wherein the assisting robotic lawn mower (100b, 100c) comprises a holding means (410), where the computing device (205, 207, 208) is adapted to provide instructions to the assisting robotic lawn mower (100b, 100c), which instructions enable the assisting robotic lawn mower (100b, 100c) to abut the first robotic lawn mower (100a), to control the holding means (410) to attach to the first robotic lawn mower (100a), and to tow the first robotic lawn mower (100a) away from its position.

38. The robotic lawn mower system (250) according to claim 37, wherein the holding means is an electromagnet (410), where the electromagnet magnetically attaches to the first robotic lawn mower (100a) upon activation.

39. The robotic lawn mower system (250) according to any one of the claims 30-38, wherein the second robotic lawn mower (100b) is the assisting robotic lawn mower.

40. The robotic lawn mower system (250) according to any one of the claims

30-39, wherein the robotic lawn mower system (250) comprises one more further robotic lawn mower (100c) according to any one of the claims 20-26, constituting a third robotic lawn mower (100c), where the computing device (205, 207, 208) is adapted to control the third robotic lawn mower (100c) to move towards the position of the first robotic lawn mower (100a) and to acquire camera images of the first robotic lawn mower (100a) and/or the second robotic lawn mower (100b) using a camera device (171).

41. The robotic lawn mower system (250) according to any one of the claims 30-38, wherein the robotic lawn mower system (250) comprises one more further robotic lawn mower (100c) according to any one of the claims 20-26, constituting a third robotic lawn mower (100c), where the third robotic lawn mower (100c) is the assisting robotic lawn mower.

42. The robotic lawn mower system (250) according to any one of the claims

27-41 , wherein the remote computing device is a user terminal (205), a remote server (207) and/or a local server (208) in a charging station (215).