SE2250370A1 - Refill system for an outdoor robotic work tool - Google Patents

Abstract

The present invention relates to a refill system for an outdoor robotic work tool (100) comprising:- a refill station (207) comprising a fluid outlet (209), and- a refill control module (211), configured to control filling of a refillable fluid container (180), which fluid container is configured to store a cleaning fluid, such as water, pressurized water or compressed gas, onboard the robotic work tool.The refill control module (211 ) is configured to allow filling of the fluid container via the fluid outlet when the robotic work tool docks with the refill station.The present invention further relates to a cleaning system comprising the refill system and the refillable fluid container, a robotic work tool system comprising the cleaning system, a method for filling a fluid container of an outdoor robotic work tool and a method for cleaning a sensor system of an outdoor robotic work tool.

Description

REFILL SYSTEM FOR AN OUTDOOR ROBOTIC WORK TOOL TECHNICAL FIELD The present invention relates to a refill system for an outdoor robotic work tool, such as a robotic lawn mower. The present invention further relates to a cleaning system comprising the refill system and the refillable fluid container, a robotic Work tool system comprising the cleaning system, a method for filling a fluid container of an outdoor robotic Work tool and a method for cleaning a sensor system of an outdoor robotic work tool.

BACKGROUND Outdoor robotic work tools, such as robotic lawn mowers, are becoming increasingly more popular. Other examples of outdoor robotic work tools used, and in which the disclosed refill system and/or cleaning system are applicable, are robotic ball collectors, robotic mine sweepers and robotic farming equipment.

The robotic work tool is normally equipped With a sensor system, Which may comprise one or more environmental detection sensors, such as one or more of an imaging sensor, a radar sensor, an IR sensor, an ultrasonic sensor and/or a Lidar sensor. The one or more environmental detection sensors are helpful When the robotic Work tool moves around in order to help its navigation ability.

The one or more environmental detection sensors may comprise an external surface, such as a lens or a protective cover, which is desirable to keep as clean as possible. lf dirt or debris would gather on this external surface, the one or more environmental detection sensors could provide false information or even stop being operable. Cleaning the external surface, such as the lens or protective cover, in a purely mechanical way may result in scratches, Which could also impair the function of the one or more environmental detection sensors.

An objective with the invention is thus to provide an improved, or at least an alternative, refill system facilitating cleaning of an outdoor robotic work tool.

SUMMARY The above object may be achieved with a refill system for an outdoor robotic work tool according to claim 1. Variations of the invention are set out in the dependent claims and in the following description.

The refill system for an outdoor robotic work tool as disclosed herein comprises: - a refill station comprising a fluid outlet, and - a refill control module, configured to control filling of a refillable fluid container, which fluid container is configured to store a cleaning fluid, such as water, pressurized water or compressed gas, onboard the robotic work tool, the refill control module being configured to allow filling of the fluid container via the fluid outlet when the robotic work tool docks with the refill station.

The refill system may form part of a cleaning system, which also comprises the refillable fluid container configured to be located onboard the robotic work tool. The refill system or the cleaning system may be included when manufacturing a robotic work tool system, such that the robotic work tool system may be sold with the refill system or the cleaning system incorporated. Further, the refill system or the cleaning system may be retrofitted into an existing robotic work tool system.

The outdoor robotic work tool may be a robotic lawn mower. lt may also be a robotic ball collector, a robotic mine sweeper or a robotic farming equipment. The robotic work tool is self-propelled. There is thus no need for a human being to move the robotic work tool around, e.g. by pushing it forwards. The robotic work tool has its own movement control module configured to control its movements. The refill control module and the movement control module may together be comprised in a control system of the robotic work tool.

The robotic work tool typically comprises at least one electric motor and at least one electric power source, such as a battery. The electric power source is typically recharge- able and the robotic work tool may thus regularly visit a charging station to recharge the electric power source. ln a typical work area of the robotic work tool, such as a garden, the work area can be enclosed by a boundary wire with the purpose of keeping the robotic work tool inside the work area. An electric control signal may be transmitted through the boundary wire, thereby generating an electromagnetic field emanating from the boundary wire. The robotic Work tool is in that case typically arranged with one or more control signal sensors adapted to sense the control signal.

Alternatively, or as a complement, the robotic work tool can be equipped with a navigation system that is adapted for satellite navigation by means of GPS, i.e. Global Positioning System, or some other GNSS system, i.e. Global Navigation Satellite System, for example using RTK, i.e. Real Time Kinematic. ln addition to this, the navigation system can be adapted for navigation by means of a local base station that e.g. can be housed in the charging station and provide a navigation signal that further increases the navigation aCCUFaCy.

The robotic work tool is normally equipped With a sensor system, Which may comprise one or more environmental detection sensors, such as one or more of an imaging sensor, a radar sensor, an IR sensor, an ultrasonic sensor and/or a Lidar sensor. The environ- mental detection sensor is helpful when the robotic work tool moves around in order to help its navigation ability. Alternatively, or as a complement, the environmental detection sensor may reduce, or preferably avoid, the risk of the robotic work tool running into objects, getting damaged by such objects and/or damaging the object. The object may be a fixed or movable object. The object e.g. may be a building, a plant, a tree, a garden equipment, an animal or a human being.

The one or more environmental detection sensors may comprise an external surface, such as a lens or a protective cover, which is desirable to keep clean. lf dirt or debris would gather on this external surface, the one or more environmental detection sensors could provide false information or even stop being operable.

Since the fluid container of the cleaning system disclosed herein is located onboard the robotic work tool, the cleaning of the external surface, such as the lens or the protective cover, of the one or more environmental detection sensors, could start directly when needed or desired. This cleaning is typically made without user interaction. With the cleaning system disclosed herein, there is no need for the robotic work tool to first move to a cleaning place, such as a cleaning station. Purely as an example, if moist dirt or debris, such as a moist leaf, would at least partly cover the external surface, e.g. the lens or the protective cover of a camera, the cleaning can start right away before the dirt or debris is dried on the external surface, e.g. the lens or the protective cover, which makes the cleaning easier, since it is much easier to remove moist dirt or debris than dried-in dirt or debris.

The possibility of immediately starting cleaning further has the advantage that the function of the one or more environmental detection sensors is retrieved as quickly as possible. For some robotic work tool system, the one or more environmental detection sensors are essential for the navigation and/or the movement control of the robotic work tool. Hence, for such robotic Work tool system, it may be highly desirable that the one or more environ- mental detection sensors operate/s correctly, since othenNise it may happen that the robotic work tool would not be able to navigate or move properly. Hence, with a prior art cleaning system performing cleaning in a cleaning station, it may happen that the robotic work tool Would not be capable of returning to the cleaning station, which would then lead to a stand-still of the robotic work tool.

The cleaning fluid may be a liquid, typically Water, or a gas, typically air. Water and/or air are often appropriate, since they are readily available. A cleaning agent may be mixed into the water. The gas may be compressed. The liquid may be pressurized.

The shape and the volume of the fluid container is preferably adapted to the size and the geometry of the robotic work tool, in which it is installed. For a small robotic work tool, e.g. having a weight of about 5 kg, the volume of the fluid container may be in the range of from 0.1 to 0.5 litres, such as e.g. 0.2 litres, While for a large robotic work tool, e.g. having a weight of about 500 kg, the volume of the fluid container may be in the range of from 1 to 10 litres, such as e.g. 5 litres. The location of the fluid container onboard the robotic work tool is preferably adapted to other components of the robotic work tool, such that the fluid container does not add to the total volume of the robotic work tool, e.g. such that it can be housed in an existing main body. lt may be preferable to locate the fluid container at or adjacent to the centre of gravity of the robotic work tool, as seen without the fluid container, such that the behaviour of the robotic work tool is influenced as little as possible by a fill level of the fluid container. This is especially desirable, When the fluid is a liquid, such as water.

The refill station comprises a fluid outlet. When the robotic work tool docks with the refill station, the fluid container can be filled with the cleaning fluid via the fluid outlet. The filling operation is controlled by the refill control module, e.g. such that filling only is allowed when the robotic work tool assumes a refill position in relation to the fluid outlet. Hence, it is possible to avoid any spillage of the cleaning fluid.

The refill control module may operate mechanically and/or electronically. Purely as an example, the robotic work tool may move a closure, a tap or a valve to an open position when moving into the refill position. The closure, tap or valve may be biased to a closed position, e.g. spring-biased, such that it closes again when the robotic work tool moves away from the refill position and stays in that closed position. Purely as another example, the robotic work tool system may comprise one or more switches, which are activated by the robotic work tool when it assumes the refill position. lf the fluid container is empty the first time the robotic work tool docks with the refill station, as the fluid is filled for the first time. Thereafter, the fluid container is filled again, i.e. the fluid container is refilled. The fluid container may be completely filled or only partly filled.

By utilizing the refill system and/or the cleaning system disclosed herein, it is provided a refill system offering automatic filling, including both the first filling and refilling, of the fluid container located onboard the robotic work tool, i.e. an automatic refill system is provided. Hence, not only the cleaning operation onboard the robotic work tool may operate auto- matically, but also the filling of the fluid container may operate automatically. Accordingly, the filling of the fluid container may be performed without interaction of a human being. lt is possible to have a completely automatic system, wherein the refill station is operated without the interaction of a human being under normal operating conditions. However, a human being may assist by providing e.g. maintenance.

The refill station may further comprise an electric charging station for charging a recharge- able electric power source of the robotic work tool. Hence, the refill station and the electric charging station may together form a common docking station for the robotic work tool, which makes it possible to perform the filling of the fluid container at least partly simulta- neously as charging the rechargeable electric power source. ln that case, the refill control module may be configured such that it allows refilling when it detects that charging starts, since that implies that the robotic work tool assumes the refill position. Alternatively, the refill station and the electric charging station may form two separate docking stations.

The term "fluidly connected" as used herein means the fluid can move, e.g. flow or stream, between the two components being fluidly connected. The two components may be directly fluidly connected, i.e. next to each other in the flow of the fluid, or they may be indirectly fluidly connected, indicating that there may be another component in between, such as piping or a pump.

The refill station may be configured to be fluidly connected to a fluid conduit for supplying the cleaning fluid to the refill station, such as a water conduit or a conduit for compressed gas, the fluid conduit being fluidly connected to the fluid outlet. The fluid conduit may comprise piping and/or a hose. By connecting the refill station to the fluid conduit, there is no practical limit to the amount of cleaning fluid, which may be supplied, since more cleaning fluid can be supplied to the refill station via the fluid conduit. The supply of the cleaning fluid from the fluid conduit may be performed automatically, e.g. controlled by a fluid supply control module, which may be combined with the refill control module and/or the movement control module in the control system. The fluid conduit may be configured to be temporary and/or permanently connected to the refill station.

The refill station may comprise a fluid tank being fluidly connected to the fluid outlet. The fluid tank is used to store cleaning fluid in the refill station. The volume of the fluid tank is preferably a number of times larger than the volume of the fluid container of the robotic work tool, such as in the range of from 3-20 times larger, preferably 5-10 times larger. By using a fluid tank, it is ascertained that there is enough cleaning fluid to fill the fluid container. The fluid tank may be temporary and/or permanently connected to the fluid conduit. The fluid tank may in that case be used to even out a flow of the cleaning fluid.

Further, the fluid tank may be used to mix in a cleaning agent.

Preferably, the fluid tank is located vertically above the fluid outlet. Thereby, the cleaning fluid may be filled into the fluid container of the robotic work tool by means of gravity, such that e.g. no pump is needed.

The refill station may comprise a rain water collector and/or an inlet for manual fluid filling being fluidly connected to the fluid tank. The inlet for manual fluid filling could be used to pour water into the fluid tank. As an alternative or a complement, the inlet may be temporarily connected to a fluid conduit or to a hose. ln that case, a human being may perform the temporary connection and disconnection.

The fluid container may be a pressure tank, Which e.g. is appropriate for gases. A fluid container for a liquid, e.g. water, may also comprise air, which may be compressed when the liquid is filled.

The refill station may comprise a gas compressor, for example an air compressor, the gas compressor being fluidly connected to the fluid outlet. The gas compressor is utilized to be able to fill the fluid container of the robotic work tool with compressed gas.

The refill system may further comprise at least one position sensor configured to detect a position of the robotic work tool in relation to the refill station, and wherein the refill control module is configured to allow filling of the fluid container, when the robotic work tool assumes the refill position in relation to the fluid outlet. Hence, it is ascertained that filling only is performed When the robotic Work tool assumes the refill position in relation to the fluid outlet, which makes it possible to avoid any spillage of the cleaning fluid. The position sensor/s may be located in the refill station and/or on or in the robotic work tool. There may also be a charging position sensor configured to detect a position of the robotic work tool in relation to the charging station. These two position sensors could be combined into a COmmOn One.

The present invention further relates to a cleaning system comprising the refill system disclosed herein and the refillable fluid container, which is configured to store a cleaning fluid, such as water, pressurized water or compressed gas, onboard the robotic work tool.

The cleaning system may in that case further comprise a fluid distributor, such as a pump, a nozzle and/or a spray device, configured to distribute the fluid onto a surface of the robotic work tool to be cleaned. The fluid distributor is directly or indirectly fluidly connected to the fluid container. Hence, also the fluid distributor is located onboard the robotic work tool.

The fluid distributor is normally located at or adjacent to the one or more environmental detection sensors, e.g. such that the cleaning fluid is distributed onto the external surface, such as onto the lens or the protective cover.

The fluid distributor may cooperate with one or more wiper blades, which also may be comprised in the cleaning system. The cleaning fluid may then be used to avoid the risk of making scratches at the external surface. The cleaning fluid may e.g. be sprayed on the external surface, e.g. on the lens or the protective cover, before or while activating the one or more wiper blades. Thereby it is avoided that the one or more wiper blades operates on the external surface when yet dry, which could result in scratches, a risk which can be avoided with the cleaning system disclosed herein.

The present invention further relates to a robotic work tool system, comprising an outdoor robotic work tool with a sensor system, and the cleaning system as disclosed herein, wherein the refillable fluid container of the cleaning system is located onboard the robotic work tool, and the cleaning fluid is adapted for cleaning of the sensor system.

The sensor system may comprise a transmitter and a receiver, the cleaning system being adapted for cleaning of the transmitter and/or the receiver. The transmitter and the receiver may combined into a common unit, i.e. a transceiver.

The sensor system may comprise one or more environmental detection sensors, such as one or more of an imaging sensor, a radar sensor, an IR sensor, an ultrasonic sensor and/or a Lidar sensor. The environmental detection sensor is helpful when the robotic work tool moves around in order to help its navigation ability. Alternatively, or as a complement, the environmental detection sensor may reduce, or preferably avoid, the risk of the robotic work tool running into objects, getting damaged by such objects and/or damaging the object. The object may be a fixed or movable object. The object may e.g. be a building, a plant, a tree, a garden equipment, an animal or a human being. ln case the sensor system comprises an imaging sensor, a light source, such as a headlamp or an IR light source, may form the transmitter and the imaging sensor may form the receiver. A radar sensor typically comprises a transmitter and a receiver, often combined into a transceiver. Also an ultrasonic sensor and/or a Lidar sensor typically comprises a transmitter and a receiver, Which may be combined into a transceiver.

The transmitter and/or the receiver may comprise an external surface, such as a lens or a protective cover, which is desirable to keep clean. Purely as an example, if a cover of a headlamp is dirty, the illumination may be uneven, which may give a false sensor signal. ln case the robotic work tool comprises a rechargeable electric power source, the robotic work tool system may comprise an electric charging station for charging the rechargeable electric power source. Preferably, the refill station and the charging station form a common docking station for the robotic work tool, which makes it possible to perform the filling at least partly simultaneously as charging the rechargeable electric power source. ln that case, the volume of the fluid container is preferably adapted to the storage capacity of the rechargeable electric power source, such that they need filling/recharging at about the same time, thereby avoiding unnecessary returns to the docking station. As an alternative, and to be on the safe side, the volume of the fluid container may be made larger, such that it is the storage capacity of the rechargeable electric power source which normally is decisive for when to return to the docking station.

As an alternative, or a complement, to a common docking station, the refill station and the electric charging station may form two separate docking stations. This could for example be appropriate if the time for filling of the fluid container is much less than the time for recharging the rechargeable electric power source and/or if the fluid conduit and the electric grid are available at different locations within the work area of the robotic work tool. ln that case, the filling of the fluid container and the recharging are performed as two independent operations. Consequently, the robotic work tool may return to the refill station when it is time to fill more cleaning fluid, independently of the charging status of the rechargeable electric power source.

The present invention also relates to a method for filling a fluid container of an outdoor robotic work tool, the method comprising: - docking the robotic work tool with a refill station, and -the refill station filling a fluid container located onboard the robotic work tool with a cleaning fluid, such as water, pressurized water or compressed gas.

Both the docking and the filling, including both the first filling and re-filling, may be performed without human interaction. lf the fluid container is empty the first time the method is to be performed, the fluid is filled for the first time. Thereafter the fluid container is filled again, i.e. refilled. The fluid container may be completely filled or only partly filled.

The method may be performed with the refill system described herein. The technical effects and advantages correspond to those described herein for the refill system and the cleaning system. The components described herein as part of the refill system or the cleaning system, may be utilized in corresponding method steps of the method.

The filling may be performed at least partly simultaneously as charging a rechargeable electric power source of the robotic work tool, e.g. in the common docking station described herein. This saves time as compared to performing filling and recharging as two independent steps performed in sequence, which e.g. is the case when the refill station and the electric charging station form two separate docking stations.

The method may further comprise: - a fill level control module monitoring a fill level of the fluid container, - the fill level control module making the robotic work tool move to the refill station when the fill level is below a refill limit.

Since the fill level control module monitors the fill level of the fluid container as well as makes the robotic work tool move to the refill station when the fill level is below a refill limit, it is possible to perform the method automatically, i.e. without human interaction. The fill level control module may be comprised in the robotic work tool, in the refill station or separate from both the refill station and the robotic work tool. lf not in the robotic work tool, there is typically provided a communication means for communication between the robotic work tool and the fill level control module.

The fill level control module may be combined with one or more of the refill control module, the movement control module and/or the optional fluid supply control module in the control system of the robotic work tool.

The fill level may be directly or indirectly monitored. lf directly monitored, the fluid container may comprise a level sensor or a pressure sensor. lf indirectly monitored, the fill level control module may keep account of how many times the sensor system of the robotic work tool is cleaned, and by multiplying with an assumed used volume per 11 Cleaning, the total consumption of cleaning fluid may be estimated. As yet an alternative, the fill level control module can monitor if the sensor performance is improved by performing the cleaning. lf not, it may be assumed that the fluid container has been emptied and needs refilling.

The present invention furthermore relates to a method for cleaning a sensor system of an outdoor robotic work tool, the method comprising: - filling the fluid container of the robotic work tool according to the method for filling a fluid container of an outdoor robotic work tool described herein - cleaning a sensor system of the robotic work tool with the cleaning fluid by means of a fluid distributor, such as a pump, a nozzle and/or a spray device, located onboard the robotic work tool, the fluid distributor distributing the cleaning fluid onto a surface of the robotic work tool to be cleaned, e.g. onto an external surface of the sensor system, such as a lens or a protective cover, the fluid distributor being fluidly connected to the fluid container.

The method may be performed with the robotic work tool system described herein. The technical effects and advantages correspond to those described herein for the robotic work tool system. The components described herein as part of the robotic work tool system, may be utilized in corresponding method steps of the method.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will hereinafter be further explained by means of non-limiting examples with reference to the appended drawings wherein: Fig. 1 shows a perspective view of an outdoor robotic work tool, exemplified as a robotic lawn mower, forming part of a robotic work tool system according to the invention. Fig. 2 shows a schematic overview of the robotic lawn mower of Fig. 1 seen from above. Fig. 3 shows a schematic overview of an exemplary work area. Fig. 4 schematically illustrates a refill station, forming part of a refill system according to the invention. Fig. 5 schematically illustrates an alternative refill station. Fig. 6 schematically illustrates a lens to be cleaned, a fluid distributor and a wiper blade. Fig. 7 illustrates a flowchart of a method according to the invention. 12 lt should be noted that the appended drawings are not necessarily drawn to scale and that the dimensions of some features of the present invention may have been exaggerated for the sake of clarity.

DETAILED DESCRIPTION The invention will in the following be exemplified by embodiments. lt should however be realized that the embodiments are included in order to explain principles of the invention and not to limit the scope of the invention, defined by the appended claims. Details from two or more of the embodiments may be combined with each other. lt 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.

Fig. 1 shows a perspective view of an outdoor robotic work tool, exemplified as a robotic lawn mower 100 and forming part of a robotic work tool system according to the invention. Fig. 2 shows a schematic overview of the robotic lawn mower 100 as seen from above. Fig. 3 shows a schematic overview of an exemplary work area 201, e.g. a garden, in which the robotic work tool, illustrated as the robotic lawn mower 100, is set to operate.

The work area 201 is delimited by a boundary. ln the illustrated embodiment, the work area 201 is enclosed by a boundary wire 203 with the purpose of keeping the robotic lawn mower 100 inside the work area 201. An electric control signal may be transmitted through the boundary wire 203, thereby generating an electromagnetic field emanating from the boundary wire 203. The robotic lawn mower 100 is in that case typically arranged with one or more control signal sensors (not shown) adapted to sense the control signal. The work area 201 is typically arranged such that the robotic lawn mower 100 can dock with a charging station 205.

Alternatively, or as a complement, the work area 201 may be delimited by a virtual boundary, e.g. provided by a map application or stored coordinates in the robotic lawn mower 100. Hence, the robotic lawn mower 100 may as an option comprise a navigation system that is adapted for satellite navigation by means of GPS, i.e. Global Positioning System, or some other GNSS system, i.e. Global Navigation Satellite System, for 13 example using RTK, i.e. Real Time Kinematic. ln addition to this, the navigation system can be adapted for navigation by means of a local base station that e.g. can be housed in the charging station 205 and provide a navigation signal that further increases the navigation accuracy.

The robotic lawn mower 100 is adapted for a fonNard travelling direction D, has a main body 140 and a plurality of wheels 130; in this example the robotic lawn mower 100 has four wheels 130, two front wheels and two rear wheels. The robotic lawn mower 100 comprises a control system 110 and at least one electric motor 150, where at least one of the wheels 130 is drivably connected to the at least one electric motor 150. Typically, two or four wheels are drivably connected. lt should be noted that even if the description herein is focused on electric motors, combustion engines may alternatively be used in combination with, or as an alternative to, 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 part being movable with respect to one another. A mono- chassis type comprises only one main body part. ln the illustrated embodiment, the robotic lawn mower100 is of a mono-chassis type, having a main body part, i.e. the main body 140. The main body 140 substantially houses all components of the robotic lawn mower 100.

The robotic lawn mower 100 comprises a grass cutting device 160, such as a rotating blade or a disc 160 with a plurality of separate cutting members, e.g. rotating blades, driven by a cutter motor 165. The energy of each cutting member typically is below 2 Joule when cutting. The weight of each cutting member is typically in the ranges of 1-5 grams, such as e.g. 3.4 grams. Thickness is typically the range of 0.5-1.0 mm, such as e.g. 0.63 mm.

The robotic lawn mower 100 has at least one rechargeable electric power source 155 for providing power to the electric motor arrangement 150 and/or the cutter motor 165. The rechargeable electric power source 155 is arranged to be charged by means of received charging current from the charging station 205, received through charging skids 156 or other suitable charging connectors. lnductive charging without galvanic contact, only by means of electric contact, is also conceivable. The rechargeable electric power source 155 may comprise one or more batteries that can be separately arranged or be arranged in an integrated manner to form a combined battery. 14 The robotic lawn mower 100 comprises at least one environmental detection sensor 170, 171, 172, 173, 174. ln the illustrated embodiment, the robotic lawn mower 100 comprises an imaging sensor 170, illustrated as a camera device, which is adapted to provide images of the environment around the robotic lawn mower 100. lf mounted at a front of the robotic lawn mower 100, as is illustrated, the imaging sensor 170 will provide images of the environment in front of the robotic lawn mower 100, for example images of an object located in front of the lawn mower 100. There may also, optionally, be provided one or more radar transceivers 171, an IR sensor 172, an ultrasonic sensor 173 and/or a Lidar sensor 174 in or on the robotic lawn mower 100, schematically indicated With dashed lines in Fig. 2. An optional at least one navigation sensor arrangement 175 and/or the optional at least one environmental detection sensor 170, 171, 172, 173, 174 forms part of a sensor system of the robotic lawn mower 100.

The control system 110 is adapted to control the at least one environmental detection sensor 170, 171, 172, 173, 174 and comprises a movement control module 111 adapted to i.a. control the speed and direction of the robotic lawn mower 100 in dependence of information acquired by means of the of the at least one environmental detection sensor 170, 171, 172, 173, 174. Generally, the control system 110 is adapted to at least partly process input data from the at least one environmental detection sensor 170, 171, 172, 173, 174. For example, the control system 110 is via the movement control module 111 adapted to control the speed and direction of the robotic lawn mower 100 in dependence of information deduced from acquired images from the imaging sensor 170, for example slowing down and being prepared to stop and change direction when approaching an animal, to avoid approaching areas occupied by humans and to move all the way to objects, cutting the grass all the way to the object. Fixed objects can be pre-programmed and intermittent objects have to be determined from time to time.

Typically, the one or more environmental detection sensors 170, 171, 172, 173, 174 comprise external surfaces, which should be clean in order to have the one or more environmental detection sensors 170, 171, 172, 173, 174 fully operable. They may e.g. comprise a lens or a protective cover, which is desirable to keep as clean as possible. For example, in the illustrated embodiment, the imaging sensor 170 comprises an external surface in the form of a protective lens 176, see Fig. 1. The sensor system may also comprise additional lenses or protective covers forming external surfaces of other sensors included in the sensor system. lf dirt or debris would gather on the external surface, e.g. the lens 176, the one or more environmental detection sensors 170, 171, 172, 173, 174 could provide false information or even stop being operable. ln order to be able to clean the external surface of the one or more environmental detection sensors 170, 171, 172, 173, 174, e.g. the lens 176, there is provided a cleaning system according to the invention. The cleaning system comprises a refillable fluid container 180 onboard the robotic lawn mower 100, see Fig. 2, and a refill system as described herein. The fluid container 180 is configured to store a cleaning fluid, such as water, pressurized water or compressed gas.

The refill system comprises a refill station 207, comprising a fluid outlet 209, and a refill control module 211, see Fig. 4, showing a schematic side view of the refill station 207.

The refill control module 211 controls filling of the fluid container 180 onboard the robotic work tool, i.e. onboard the robotic lawn mower 100 in the illustrated embodiment. The refill control module 211 allows filling of the fluid container 180 via the fluid outlet 209 of the refill station 207 and a fluid inlet 182 of the robotic lawn mower 100, when the robotic lawn mower 100 docks with the refill station 207. The cleaning fluid then passes via the fluid outlet 209 of the refill station 207 and via the fluid inlet 182 of the robotic work tool 100, into the fluid container 180. ln the illustrated embodiment, the refill control module 211 operates purely mechanically. lt comprises a closure, which is pushed to an open position by the robotic lawn mower 100, when it moves into a refill position. The closure may be biased to a closed position, e.g. spring-biased, such that it automatically closes again, when the robotic lawn mower 100 moves away from the refill position, and then stays in that closed position.

As an alternative or a complement, the refill control module may be electronically controlled or be configured to operate with a combination of mechanical and electronical control. Purely as an example, the robotic work tool system may comprise one or more switches, in or on the robotic work tool 100 and/or in or on the refill station 207, which are activated by the robotic work tool 100 when it approaches or assumes the refill position. ln that case, the refill control module 211 could comprise a refill control unit, which may be 16 located in the refill station, as indicated by dashed lines 213', or in the robotic lawn mower 100, not illustrated.

The refill station 207 may be combined with the charging station 205, as is illustrated in Fig. 3 and 4. This makes it possible to perform the filling of the fluid container 180 at least partly simultaneously as charging the rechargeable electric power source 155, e.g. via one or more charging connectors 206 cooperating with the charging skids 156 of the robotic lawn mower 100. ln the illustrated embodiment, the refill station 207 is fluidly connected to a fluid conduit 215, which may e.g. supply water. ln the illustrated embodiment, the fluid conduit 215 is indirectly connected to the fluid outlet 209 via a fluid tank 219. However, fluid conduit 215 may alternatively be directly connected to the fluid outlet 209, i.e. omitting the fluid tank 219. Dependent on the kind of fluid, the fluid tank 219 may be a pressure tank. The supply of the cleaning fluid from the fluid conduit 215 may be performed automatically, e.g. controlled by a fluid supply control module 217, which may be combined with the refill control module 211 and/or the movement control module 111 in the control system.

Since the fluid tank 219 of Fig. 4 is located vertically above the fluid container 180 of the robotic work tool, i.e. the robotic lawn mower 100, the cleaning fluid may be filled into the fluid container 180 by means of gravity, such that e.g. no pump is needed.

As an alternative, or a complement, to connecting the fluid tank 219 to the fluid conduit 215, it may also be possible to fill the fluid tank 219 via an inlet 221 for manual filling, the inlet 221 being directly or indirectly fluidly connected to the fluid tank 219. ln that case, the inlet 221 may be temporarily connected to a hose supplying the fluid, e.g. water, or a human being may fill the fluid tank 219 by means of a Waterjug.

Yet an alternative, or a complement, is to use a rain water collector (not shown), which is directly or indirectly fluidly connected to the fluid tank 219. ln that case collected rain water, possibly with addition of a cleaning agent, may be used as the cleaning fluid.

The cleaning system may further comprise at least one position sensor, illustrated as three position sensors 231, 233, 235 in Fig. 4. They are configured to detect a position of the robotic work tool, here the robotic lawn mower 100, in relation to the refill station 207. 17 The refill control module 211 is configured to allow filling of the fluid container 180, when the robotic work tool 100 assumes the refill position in relation to the fluid outlet 209. Hence, it is ascertained that filling only is performed when the robotic work tool 100 assumes the refill position in relation to the fluid outlet 209, which makes it is possible to avoid any spillage of the cleaning fluid. As an alternative, or a complement, there may also be one or more position sensors 191, 193 located in or on the robotic work tool 100, see Fig. 1.

Fig. 5 schematically illustrates an alternative refill station 307. Similar as for the refill station 207 shown in Fig. 4, it is combined in a common docking station together with the charging station 205. The alternative refill station 307 comprises a gas compressor 305. The gas compressor 305 takes ambient air from the surroundings via an inlet 321 and compresses it. The gas compressor 305 is in turn connectable to the fluid container 180 onboard the robotic work tool, i.e. onboard the robotic lawn mower 100, via the fluid outlet 309. A refill control module 311 controls filling of the fluid container 180. The refill control module 311 may work in a corresponding way as already described above for the refill control module 211 of Fig. 4.

As an alternative, or a complement, to the common docking station, as illustrated in Fig. 3-5, the refill station may be separate from the charging station 205 as indicated by dashed lines 207' in Fig. 3. This could for example be appropriate if the time for filling of the fluid container 180 is much less than the time for charging the rechargeable electric power source 155 and/or if the fluid conduit 215 and the electric grid are available at different locations within the work area of the robotic work tool 100. ln that case, the filling of the fluid container 180 and the recharging are performed as two independent opera- tions. Consequently, the robotic work tool 100 may return to the refill station 207' when it is time to fill more of the cleaning fluid, independently of the charging status of the rechargeable electric power source 155.

A robotic work tool system according to the invention comprises the outdoor robotic work tool, with its sensor system, illustrated as the robotic lawn mower 100 in Fig. 1-5, and the cleaning system as disclosed herein, wherein the refillable fluid container 180 of the cleaning system is located onboard the robotic work tool 100, and the cleaning fluid is adapted for cleaning of the sensor system. 18 The cleaning system may as an option comprise a fluid distributor, see Fig. 6, in which the fluid distributor is exemplified as a nozzle 177. The nozzle 177 is configured to spray the cleaning fluid over the external surface which is to be cleaned, e.g. the lens 176 of the imaging sensor 170 illustrated in Fig. 1 and 2. The nozzle 177 cooperates with a wiper blade 178, which is also comprised in the cleaning system. The cleaning fluid may then be used to avoid the risk of the wiper blade 178 making scratches at the lens 176. The cleaning fluid may e.g. be sprayed on the lens 176, before or while activating the wiper blade 178. Thereby it is avoided that the wiper blade 178 operates on the lens 176 when yet dry, which could have resulted in scratches, a risk which can be avoided with the cleaning system disclosed herein.

The cleaning system may also be utilized to clean a transmitter of the sensor system, such as a headlamp, not illustrated, for normal light or IR, which may be used together with the imaging sensor 170, which functions as a receiver. The cleaning system may in that case be used to clean the transmitter and/or the receiver. Purely as an example, a fluid distributor like the one of Fig. 6, a nozzle 177, combined with the wiper blade 178 would be suitable for cleaning a protective cover of a headlamp.

Afill level control module 184 on board the robotic lawn mower 100 monitors the fill level of the fluid container 180 as well as makes the robotic lawn mower 100 move to the refill station 207, 207', 307 when the fill level is below a refill limit. The fill level control module may alternatively be located in the refill station 207, 207', 307 or separate from both the refill station 207, 207', 307 and the robotic work tool 100. lf not in the robotic work tool 100, there is typically provided a communication means, not illustrated, for communication between the robotic work tool and the fill level control module.

The fill level control module 184 may be combined with one or more of the refill control module 211, the movement control module 111 and/or the optional fluid supply control module 217 in the control system 110 of the robotic work tool 100.

The fill level may be directly or indirectly monitored. lf directly monitored, the fluid container 180 may comprise a level sensor or a pressure sensor, not illustrated, of types known to the skilled person. lf indirectly monitored, the fill level control module 184 may keep account of how many times the sensor system of the robotic work tool 100 is cleaned, e.g. the external surface exemplified as the lens 176, and by multiplying with an 19 assumed used volume per Cleaning, the total consumption of cleaning fluid may be estimated. As yet an alternative, the fill level control module 184 can monitor if the sensor performance is improved by performing the cleaning. lf not, it may be assumed that the fluid container 180 has been emptied and needs filling.

A method 400 for filling a fluid container 180 of an outdoor robotic work tool 100 according to the invention, see flowchart in Fig. 7, comprises: 430: Docking the robotic work tool 100 with a refill station 207, 207', 307, and 440: The refill station 207, 207', 307 filling a fluid container 180 located onboard the robotic work tool 100 with a cleaning fluid, such as water, pressurized water or compressed gas.

Both the step 430 of docking and the step 440 of filling can be performed without human interaction, as described herein. The method may be performed with the refill system described herein. The components described herein as part of the refill system or the cleaning system, may hence be utilized in corresponding method steps of the method.

The step 440 of filling may be performed at least partly simultaneously as a step 450 of charging a rechargeable electric power source 155 of the robotic work tool 100, e.g. in the common docking station described herein. This saves time as compared to performing the step 440 of filling and the step 450 of recharging as two independent steps performed in sequence, which e.g. is the case when the refill station 207' and the electric charging station 205 form two separate docking stations.

The method 400 may further comprise the optional steps: 410: Afill level control module 184 monitoring a fill level of the fluid container 180, 420: The fill level control module 184 making the robotic work tool 100 move to the refill station 207, 207', 307 when the fill level is below a refill limit.

Since the fill level control module 184 monitors the fill level of the fluid container 180 as well as makes the robotic work tool 100 move to the refill station 207, 207', 307 when the fill level is below a refill limit, it is possible to perform the method automatically, i.e. without human interaction. The fill level control module 184 may be comprised in the robotic work tool 100, in the refill station 207, 207', 307 or separate from both the refill station 207, 207', 307 and the robotic work tool 100. lf not in the robotic work tool 100, there is typically provided a communication means, not illustrated, for communication between the robotic work tool and the fill level control module.

The fill level control module 184 may be combined with one or more of the refill control module 211, the movement control module 111 and/or the optional fluid supply control module 217 in the control system 110 of the robotic work tool 100. As described above, the fill level may be directly or indirectly monitored.

The present invention furthermore relates to a method for cleaning a sensor system of an outdoor robotic work tool, the method comprising: 410, 420, 430, 440, 450: The steps of filling the fluid container of the robotic work tool according to the method for filling a fluid container of an outdoor robotic work tool described herein. 460: Cleaning a sensor system of the robotic work tool 100 with the cleaning fluid by means of a fluid distributor, such as a pump, a nozzle 177 and/or a spray device, located onboard the robotic work tool 100, the fluid distributor distributing the cleaning fluid onto a surface 176 of the robotic work tool 100 to be cleaned, the fluid distributor being fluidly connected to the fluid container 180.

The method for cleaning a sensor system of an outdoor robotic work tool may be performed with the robotic work tool system described herein.

Further modifications of the invention within the scope of the appended claims are feasible. As such, the present invention should not be considered as limited by the embodiments and figures described herein. Rather, the full scope of the invention should be determined by the appended claims, with reference to the description and drawings.

Claims (1)

1.Claims A refill system for an outdoor robotic work tool (100), the refill system comprising: - a refill station (207, 207', 307) comprising a fluid outlet (209, 309), and - a refill control module (211), configured to control filling of a refillable fluid container (180), which fluid container (180) is configured to store a cleaning fluid, such as water, pressurized water or compressed gas, onboard the robotic work tool (100), the refill control module (211) being configured to allow filling of the fluid container (180) via the fluid outlet (209, 309) when the robotic work tool (100) docks with the refill station (207, 207', 307). The refill system according to claim 1, wherein the refill station (207, 207', 307) further comprises an electric charging station (205) for charging a rechargeable electric power source (155) of the robotic work tool (100). The refill system according to any one of the preceding claims, wherein the refill station (207, 207', 307) is configured to be fluidly connected to a fluid conduit (215) for supplying the cleaning fluid to the refill station (207, 207', 307), such as a water conduit or a conduit for compressed gas, the fluid conduit (215) being fluidly connected the fluid outlet (209, 309). The refill system according to any one of the preceding claims, wherein the refill station (207, 207') comprises a fluid tank (219) being fluidly connected to the fluid outlet (209), preferably the fluid tank (219) being located vertically above the fluid outlet (209). The refill system according to claim 4, wherein the refill station (207, 207') comprises a rain water collector and/or an inlet (221) for manual fluid filling being fluidly connected to the fluid tank (219). The refill system according to any one of the preceding claims, wherein the fluid container is a pressure tank. The refill system according to any one of the preceding claims, wherein the refill station (307) comprises a gas compressor (305), for example an air compressor,the gas Compressor (305) being fluidly connected to the fluid outlet (309). The refill system according to any one of the preceding claims, wherein the refill system further comprises at least one position sensor (191, 193; 231, 233, 235) configured to detect a position of the robotic work tool (100) in relation to the refill station (207, 207', 307), and wherein the refill control module (211) is configured to allow filling of the fluid container (180) when the robotic work tool (100) assumes a refill position in relation to the fluid outlet (209, 309). A cleaning system comprising: -the refill system according to any one of the preceding claims, and -the refillable fluid container (180) configured to store a cleaning fluid, such as water, pressurized water or compressed gas, onboard the robotic work tool (100). The cleaning system according to claim 9, wherein the cleaning system further comprises a fluid distributor (177), such as a pump, a nozzle and/or a spray device, configured to distribute the fluid onto a surface (176) of the robotic work tool (100) to be cleaned, the fluid distributor (177) being fluidly connected to the fluid container (180). A robotic work tool (100) system, comprising - an outdoor robotic work tool (100) with a sensor system, and -the cleaning system according to claim 9 or 10, wherein the refillable fluid container (180) of the cleaning system is located onboard the robotic work tool (100), and the cleaning fluid is adapted for cleaning of the sensor system. The robotic Work tool (100) system according to claim 11, wherein the sensor system comprises a transmitter and a receiver, the cleaning system being adapted for cleaning of the transmitter and/or the receiver. The robotic work tool (100) system according to claim 11 or 12, wherein the sensor system comprises one or more environmental detection sensors, such as one or more of an imaging sensor (170), a radar sensor (171), an IR sensor (172),an ultrasonic sensor (173) and/or a Lidar sensor (174). The robotic work tool (100) system according to claim 11, 12 or 13, wherein the robotic work tool (100) comprises a rechargeable electric power source (155), wherein the robotic work tool (100) system comprises an electric charging station (205) for charging the rechargeable electric power source (155), and wherein the refill station (207, 307) and the charging station (205) form a common docking station for the robotic work tool (100). A method (400) for filling a fluid container (180) of an outdoor robotic work tool (100), the method comprising: - docking (430) the robotic work tool (100) with a refill station (207, 207', 307), -the refill station (207, 207', 307) filling (440) a fluid container (180) located onboard the robotic work tool (100) with a cleaning fluid, such as water, pressurized water or compressed gas, preferably the filling (440) being performed at least partly simultaneously as charg- ing (450) a rechargeable electric power source (155) of the robotic work tool (100). The method (400) according to claim 15, further comprising: - a fill level control module (184) monitoring (410) a fill level of the fluid container (180), - the fill level control module (184) making (420) the robotic work tool (100) move to the refill station (207, 207', 307) when the fill level is below a refill limit. .A method (400) for cleaning a sensor system of an outdoor robotic work tool (100), the method comprising: - filling the fluid container (180) of the robotic work tool (100) according to the method of claim 15 or 16, - cleaning (460) a sensor system of the robotic work tool (100) with the cleaning fluid by means of a fluid distributor (177), such as a pump, a nozzle and/or a spray device, located onboard the robotic work tool (100), the fluid distributor (177) distributing the cleaning fluid onto a surface (176) of the robotic work tool (100) to be cleaned, the fluid distributor (177) being fluidly connected to the fluid container (180).