SE2150161A1 - Improved navigation for a robotic work tool - Google Patents

Improved navigation for a robotic work tool

Info

Publication number
SE2150161A1
SE2150161A1 SE2150161A SE2150161A SE2150161A1 SE 2150161 A1 SE2150161 A1 SE 2150161A1 SE 2150161 A SE2150161 A SE 2150161A SE 2150161 A SE2150161 A SE 2150161A SE 2150161 A1 SE2150161 A1 SE 2150161A1
Authority
SE
Sweden
Prior art keywords
work tool
robotic
robotic work
reached
distance
Prior art date
Application number
SE2150161A
Other versions
SE544910C2 (en
Inventor
Jonas Holgersson
Original Assignee
Husqvarna Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Husqvarna Ab filed Critical Husqvarna Ab
Priority to SE2150161A priority Critical patent/SE544910C2/en
Priority to PCT/SE2022/050106 priority patent/WO2022173343A1/en
Priority to EP22704604.2A priority patent/EP4291013A1/en
Publication of SE2150161A1 publication Critical patent/SE2150161A1/en
Publication of SE544910C2 publication Critical patent/SE544910C2/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S13/56—Discriminating between fixed and moving objects or between objects moving at different speeds for presence detection
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01D—HARVESTING; MOWING
    • A01D34/00—Mowers; Mowing apparatus of harvesters
    • A01D34/006—Control or measuring arrangements
    • A01D34/008—Control or measuring arrangements for automated or remotely controlled operation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/70—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using electromagnetic waves other than radio waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/881—Radar or analogous systems specially adapted for specific applications for robotics
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
    • G01S15/06—Systems determining the position data of a target
    • G01S15/08—Systems for measuring distance only
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
    • G05D1/02—Control of position or course in two dimensions
    • G05D1/021—Control of position or course in two dimensions specially adapted to land vehicles
    • G05D1/0259—Control of position or course in two dimensions specially adapted to land vehicles using magnetic or electromagnetic means
    • G05D1/0265—Control of position or course in two dimensions specially adapted to land vehicles using magnetic or electromagnetic means using buried wires
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
    • G05D1/02—Control of position or course in two dimensions
    • G05D1/021—Control of position or course in two dimensions specially adapted to land vehicles
    • G05D1/0276—Control of position or course in two dimensions specially adapted to land vehicles using signals provided by a source external to the vehicle
    • G05D1/0278—Control of position or course in two dimensions specially adapted to land vehicles using signals provided by a source external to the vehicle using satellite positioning signals, e.g. GPS
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
    • G05D1/20—Control system inputs
    • G05D1/24—Arrangements for determining position or orientation
    • G05D1/247—Arrangements for determining position or orientation using signals provided by artificial sources external to the vehicle, e.g. navigation beacons
    • G05D1/248—Arrangements for determining position or orientation using signals provided by artificial sources external to the vehicle, e.g. navigation beacons generated by satellites, e.g. GPS
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S901/00—Robots
    • Y10S901/01—Mobile robot

Landscapes

  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Automation & Control Theory (AREA)
  • Electromagnetism (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Acoustics & Sound (AREA)
  • Robotics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental Sciences (AREA)
  • Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)
  • Manipulator (AREA)

Abstract

A robotic work tool (100) configured to operate in a work area (205), the robotic work tool (100) comprising a controller (110) configured to cause the robotic work tool to follow (410) a first side (S1) of the work area (205) at a distance for the first side (S1); determine (420) that an end (EP1, EP2) has been reached and in response thereto cause the robotic work tool to make a turn (430) and follow (440) the first side (S1) of the work area (205) at a next distance; determine that a middle (M) has been reached (450) and in response thereto cause the robotic work tool to proceed to a second side (S2) and follow (470) the second side (S2) of the work area (205) at a first distance for the second side (S2); determine that an end (EP1, EP2) has been reached and in response thereto cause the robotic work tool to make a turn and follow (480) the second side (S2) of the work area (205) at a next distance.

Description

IMPROVED NAVIGATION FOR A ROBOTIC WORK TOOL TECHNICAL FIELDThis application relates to robotic Work tools and in particular to a systemand a method for providing an improved navigation for a robotic Work tool, such as a laWnmoWer.
BACKGROUND Automated or robotic Work tools such as robotic laWnmoWers are becomingincreasingly more popular. In a typical deployment a Work area, such as a garden, theWork area is enclosed by a boundary Wire With the purpose of keeping the roboticlaWnmoWer inside the Work area.
An electric control signal may be transmitted through the boundary Wirethereby generating an (electro-) magnetic field emanating from the boundary Wire. Therobotic Work tool is typically arranged With one or more (electro-) magnetic sensorsadapted to sense the control signal.
The Work areas, such as gardens may comprise passages that are narroWcompared to the size of the robotic laWnmoWer, Which introduces a risk of the roboticWork tool getting stuck in the passage or at least not being able to navigate properly andtherefor unable to properly or sufficiently operate in the passage in a manner that servicesthe Whole area of the passage properly.
Thus, there is a need for an improved manner of enabling a reliable operationof a robotic Work tool, such as a robotic laWnmoWer, even in areas that are difficult to maneuver in.
SIHVIMARY It is therefore an object of the teachings of this application to overcome or atleast reduce those problems by providing a robotic Work tool configured to operate in aWork area, the robotic Work tool comprising a controller configured to cause the robotic Work tool to follow a first side of the Work area at a distance for the first side; determine that an end has been reached and in response thereto cause the robotic work tool tomake a turn and follow the first side of the work area at a next distance; deterrnine that amiddle has been reached and in response thereto cause the robotic work tool to proceedto a second side and follow the second side of the work area at a first distance for thesecond side; deterrnine that an end has been reached and in response thereto cause therobotic work tool to make a tum and follow the second side of the work area at a nextdistance.
In one embodiment the controller is further configured to cause the roboticwork tool to proceed to second side after it is deterrnined that an end is reached.
In one embodiment the robotic work tool comprises a first magnetic sensorand a magnetic sensor second, wherein the controller is further configured to deterrninethat the middle is reached based on comparing a signal strength received by the firstmagnetic sensor and a signal strength received by the second magnetic sensor.
In one embodiment the controller is further configured to repeat followingthe first side and/or the second side at a next distance until it is deterrnined that themiddle is reached.
In one embodiment the controller is further configured to perform anadditional lap as the middle is reached.
In one embodiment the controller is further configured to perform anadditional lap as the middle is reached from the first side.
In one embodiment the controller is further configured to perform anadditional lap as the middle is reached from the second side.
In one embodiment the controller is further configured to deterrnine whetherto perform the additional lap or not based on a shape of the first side and/or a shape ofthe second side.
In one embodiment the robotic work tool comprises a satellite navigationsensor, wherein the controller is further configured to deterrnine that the end is reachedbased on the satellite navigation sensor.
In one embodiment the robotic work tool comprises a deduced reckoningnavigation sensor, wherein the controller is further configured to deterrnine that the end is reached based on the deduced reckoning navigation sensor.
In one embodiment the first distances are smaller than the next distances.
In one embodiment the first distances are the same.
In one embodiment the first distance is larger than a zone where a signalstrength is reduced due to a polarity change.
In one embodiment the next distance is increased by an amount smaller thanor equal to the width of a work tool comprised in the robotic Working tool.
In one embodiment the work area comprises terrain that is of varyingaltitude; obstacles that are not easily discemed from the ground; and/or obstacles thatare overhanging.
In some embodiments the robotic work tool is a robotic lawnmower.
In one embodiment the first side and/or second side is a side of a passagecomprised in the work area.
It is also an object of the teachings of this application to overcome theproblems by providing a method for use in a robotic work tool configured to operate ina work area, the method comprising following a first side of a work area at a distancefor the first side; deterrnining that an end has been reached and in response theretomaking a tum and following the first side of the work area at a next distance;deterrnining that a middle has been reached and in response thereto proceeding to asecond side and following the second side of the work area at a first distance for thesecond side; deterrnining that an end has been reached and in response thereto make atum and follow the second side of the work area at a next distance.
Other features and advantages of the disclosed embodiments will appearfrom the following detailed disclosure, from the attached dependent claims as well asfrom the drawings. Generally, all terms used in the claims are to be interpretedaccording to their ordinary meaning in the technical field, unless explicitly definedotherwise herein. All references to "a/an/the [element, device, component, means, step,etc.]" are to be interpreted openly as referring to at least one instance of the element,device, component, means, step, etc., unless explicitly stated otherwise. The steps ofany method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in further detail under reference to theaccompanying drawings in which: Figure 1A shows an example of a robotic lawnmower according to someembodiments of the teachings herein; Figure lB shows a schematic View of the components of an example of arobotic work tool being a robotic lawnmower according to an example embodiment ofthe teachings herein; Figure 1C shows a schematic View of a work tool of an example of a roboticwork tool being a robotic lawnmower according to an example embodiment of theteachings herein; Figure 2 shows an example of a robotic work tool system being a roboticlawnmower system according to an example embodiment of the teachings herein; Figure 3 shows a schematic View of a subsection of a work area where arobotic work tool is conf1gured to operate according to an example embodiment of theteachings herein; Figure 4 shows a corresponding flowchart for a method according to anexample embodiment of the teachings herein; Figure 5A and figure 5B shows a schematic View of an altemativesubsection of a work area where a robotic work tool is conf1gured to operate accordingto an example embodiment of the teachings herein; and Figure 6A and figure 6B each shows a schematic illustration of zones in a subsection of a work area according to an example embodiment of the teachings herein.
DETAILED DESCRIPTION The disclosed embodiments will now be described more fully hereinafterwith reference to the accompanying drawings, in which certain embodiments of theinvention are shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the embodiments set forth herein.
Like reference numbers refer to like elements throughout.
It should be noted that even though the description given herein will befocused on robotic lawnmowers, the teachings herein may also be applied to, roboticball collectors, robotic mine sweepers, robotic farrning equipment, or other robotic worktools where passages or narrow areas may have to be traversed.
Figure 1A shows a perspective view of a robotic work tool 100, hereexemplified by a robotic lawnmower 100, having a body 140 and a plurality of wheels130 (only one side is shown). The robotic work tool 100 may be a multi-chassis type ora mono-chassis type (as in figure 1A). A multi-chassis type comprises more than onemain body parts that are movable with respect to one another. A mono-chassis typecomprises only one main body part.
The robotic lawnmower 100 may comprise charging skids for contactingcontact plates (not shown in figure 1) when docking into a charging station (not shownin figure 1, but referenced 210 in figure 2) for receiving a charging current through, andpossibly also for transferring inforrnation by means of electrical communicationbetween the charging station and the robotic lawnmower 100.
Figure 1B shows a schematic overview of the robotic work tool 100, alsoexemplified here by a robotic lawnmower 100. In this example embodiment the roboticlawnmower 100 is of a mono-chassis type, having a main body part 140. The main bodypart 140 substantially houses all components of the robotic lawnmower 100. The roboticlawnmower 100 has a plurality of wheels 130. In the exemplary embodiment of figure1B the robotic lawnmower 100 has four wheels 130, two front wheels and two rearwheels. At least some of the wheels 130 are drivably connected to at least one electricmotor 150. It should be noted that even if the description herein is focused on electricmotors, combustion engines may altematively be used, possibly in combination with anelectric motor. In the example of figure 1B, each of the wheels 130 is connected to arespective electric motor. This allows for driving the wheels 130 independently of oneanother which, for example, enables steep tuming and rotating around a geometricalcenter for the robotic lawnmower 100. It should be noted though that not all wheelsneed be connected to each a motor, but the robotic lawnmower 100 may be arranged tobe navigated in different manners, for example by sharing one or several motors 150. In an embodiment where motors are shared, a gearing system may be used for providing the power to the respective wheels and for rotating the wheels in different directions. Insome embodiments, one or several wheels may be uncontrolled and thus simply react tothe movement of the robotic lawnmower 100.
The robotic lawnmower 100 also comprises a grass cutting unit 160, such asa rotating blade 160 driven by a cutter motor 165. The grass cutting device being anexample of a work tool 160 for a robotic work tool 100. The robotic lawnmower 100also has (at least) one battery 155 for providing power to the motor(s) 150 and/or thecutter motor 165.
The robotic lawnmower 100 also comprises a controller 110 and a computerreadable storage medium or memory 120. The controller 110 may be implementedusing instructions that enable hardware functionality, for example, by using executablecomputer program instructions in a general-purpose or special-purpose processor thatmay be stored on the memory 120 to be executed by such a processor. The controller110 is configured to read instructions from the memory 120 and execute theseinstructions to control the operation of the robotic lawnmower 100 including, but notbeing limited to, the propulsion of the robotic lawnmower. The controller 110 may beimplemented using any suitable, available processor or Programmable Logic Circuit(PLC). The memory 120 may be implemented using any commonly known technologyfor computer-readable memories such as ROM, RAM, SRAM, DRAM, FLASH, DDR,SDRAM or some other memory technology.
The robotic lawnmower 100 may further be arranged with a wireless com-munication interface 115 for communicating with other devices, such as a server, apersonal computer or smartphone, the charging station, and/or other robotic work tools.Examples of such wireless communication devices are Bluetooth®, WiFi®(IEEE802. 1 lb), Global System Mobile (GSM) and LTE (Long Term Evolution), toname a few.
For enabling the robotic lawnmower 100 to navigate with reference to aboundary wire emitting a magnetic field caused by a control signal transmitted throughthe boundary wire, the robotic lawnmower 100 is further configured to have at least onemagnetic field sensor 170 arranged to detect the magnetic field (not shown) and for detecting the boundary wire and/or for receiving (and possibly also sending) information to/ from a signal generator (will be discussed with reference to figure 2). Insome embodiments, the sensors 170 may be connected to the controller 110, possiblyvia filters and an amplifier, and the controller 110 may be configured to process andevaluate any signals received from the sensors 170. The sensor signals are caused by themagnetic field being generated by the control signal being transmitted through theboundary wire. This enables the controller 110 to determine whether the roboticlawnmower 100 is close to or crossing the boundary wire, or inside or outside an areaenclosed by the boundary wire.
In some embodiments, the robotic lawnmower 100 may further comprise atleast one navigation sensor, such as a beacon navigation sensor and/or a satellitenavigation sensor 180. The beacon navigation sensor may be a Radio Frequencyreceiver, such as an Ultra Wide Band (UWB) receiver or sensor, configured to receivesignals from a Radio Frequency beacon, such as a UWB beacon. Altematively oradditionally, the beacon navigation sensor may be an optical receiver conf1gured toreceive signals from an optical beacon. The satellite navigation sensor may be a GPS(Global Positioning System) device or other Global Navigation Satellite System(GNSS) device.
In some embodiments, the robotic lawnmower 100 may further comprise atleast one deduced reckoning navigation sensor 190, such as an accelerometer and/or anodometer to mention a few examples. Utilizing the deduced reckoning navigationsensor 190, the robotic work tool 100 is able to navigate at some accuracy throughcomplicated mowing pattems even when no satellite reception is reliably received.
Figure 1C shows a schematic view of a work tool of an example of a roboticwork tool being a robotic lawnmower according to an example embodiment of theteachings herein.
Fig. 1C schematically illustrates a cutting unit 160 according to someembodiments of the cutting assembly 1 according to the present disclosure. The cuttingunit 160 comprises a cutting disc 161 and a cutting member 162 arranged at a peripheryof the cutting disc 161. For reasons of brevity and clarity, the cutting unit 160 in Fig. 16is illustrated as comprising only one cutting member 162. However, the cutting unit 160 may comprise more than one cutting member 162, such as two, three, four, five, or six cutting members 162. The kinetic energy of each cutting member 162 of the cutting unit160 as described herein may be deterrnined by means of the following forrnula: El<=l/2*mv^2 WhereEk is the kinetic energy, in J oules;m is the mass, of reckonable length L of the cutting member 162, in kilograms, Wherein the reckonable length L of the cutting member 162 may bethe length L between the pivot axis 166 of the cutting member 162 and the radiallyouter portion 163 of a cutting member 162; V is the maximum attainable Velocity of the point z Which is halfway along the reckonable length L of the cutting member 162, in metres per second.
Therefore v=0, 1 047n[r-L/ 2] Where n is the maximum rotational speed, in reVolutions per minute; r is the distance from the rotational axis Ax of the cutting unit 160 to theradially outer portion 163 of a cutting member 162, in metres; Lis the reckonable length of the cutting member 162, in metres.
The piVot axis 166 of a cutting member 162 coincides With a centre line of ahole 164 conf1gured for attachment of the cutting member 162.
According to some embodiments of the cutting arrangement, the distance rfrom the rotational axis Ax of the cutting unit 160 to the radially outer portion 163 of acutting member 162 is Within the range of 160 cm to 20 cm, or is Within the range of 6cm to 12 cm, or is approximately 8.5 cm.
According to some embodiments of the cutting unit 3, the reckonable lengthL of the cutting member 162 is Within the range of 1 cm to 9 cm, or is Within the rangeof 1.7 cm to 6 cm, or is approximately 3.4 cm.
According to some embodiments of the cutting unit 160, the mass m, ofreckonable length L of the cutting member 162, is Within the range of 1 to 25 grams, or is Within the range of 1.7 to 6.5 grams, or is approximately 3.4 grams.
According to some embodiments, the thickness of the cutting member 162,i.e. the thickness of the cutting member 162 measured in a direction perpendicular to therotational plane of the cutting member 162, is Within the range of 0.2 mm to 3.5 mm, oris Within the range of 0.32 mm to 1.2 mm, or is approximately 0.63 mm.
According to some embodiments, the height h of the cutting member 162 ofthe cutting unit 160 is Within the range of 0.7 cm to 6 cm, or is Within the range of 1 cmto 2.9 cm, or is approximately 1.9 cm.
According to some embodiments of the cutting arrangement, the diameter ofthe cutting disc 161 of the cutting unit 160 is Within the range of 5 cm to 39 cm, or isWithin the range of 8 cm to 20 cm, or is approximately 14.3 cm.
According to some embodiments, the maximum attainable Velocity V of thepoint z Which is half Way along the reckonable length L of the cutting member 162 isWithin the range of 10 to 80 metres per second, or is Within the range of 15 to 50 metresper second, or is approximately 34 metres per second.
According to some embodiments, the maximum rotational speed of thecutting unit 160 is Within the range of 1 000 to 8 500 revolutions per minute, or isWithin the range of 2 400 to 7 200 reVolutions per minute, or is approximately 4 800revolutions per minute.
Figure 2 shows a schematic View of a robotic Work tool system 200 in someembodiments. The schematic View is not to scale. The robotic Work tool system 200comprises a robotic Work tool 100. As With figures 1A and 1B, the robotic Work tool isexemplified by a robotic laWnmoWer, Whereby the robotic Work tool system may be arobotic laWnmoWer system or a system comprising a combinations of robotic Worktools, one being a robotic laWnmoWer, but the teachings herein may also be applied toother robotic Work tools adapted to operate Within a Work area.
The robotic Work tool system 200 may also comprises charging station 210Which in some embodiments is arranged With a signal generator 215 and a boundaryWire 220.
The signal generator is arranged to generate a control signal 225 to betransmitted through the boundary Wire 220. To perform this, the signal generator is arranged With a controller and memory module. The controller and memory module operates and functions in the same manner as the controller 110 and memory 120 of therobotic work tool 100. The controller and memory module may also be the controllerand memory module of the charging station, hereafter simply referred to as thecontroller 216.
In one altemative or additional embodiment the controller and memorymodule may also comprise or be connected to a communication interface (not shownexplicitly but considered to be part of the controller and memory module). Thecommunication interface is enabled for communicating with other devices, such as aserver, a personal computer or smartphone, a robotic work tool 100, another signalgenerator 215 and/or another charging station 210 using a wireless communicationstandard. Examples of such wireless communication standards are Bluetooth®, WiFi®(IEEE802.1 lb), Global System Mobile (GSM) and LTE (Long Term Evolution), toname a few.
The boundary wire 220 is arranged to enclose a work area 205, in which therobotic lawnmower 100 is supposed to serve. The control signal 225 transmittedthrough the boundary wire 220 causes a magnetic field (not shown) to be emitted.
In some embodiments the control signal 225 is a sinusoid periodic currentsignal. In some embodiments the control signal 225 is a pulsed current signalcomprising a periodic train of pulses. In some embodiments the control signal 225 is acoded signal, such as a CDMA signal.
As an electrical signal is transmitted through a wire, such as the controlsignal 225 being transmitted through the boundary wire 220, a magnetic field isgenerated. The magnetic field may be detected using field sensors, such as Hall sensors.A sensor - in its simplest form -is a coil surrounding a conductive core, such as aferrite core. The amplitude of the sensed magnetic field is proportional to the derivate ofthe control signal. A large variation (fast and/or of great magnitude) results in a highamplitude for the sensed magnetic field.
The variations are sensed and compared to a reference signal or pattem ofvariations in order to identify and thereby reliably sense the control signal.
The robotic work tool system 200 may also optionally comprise at least one beacon (not shown) to enable the robotic lawnmower to navigate the work area using 11 the beacon navigation sensor(s) 180 or in combination with the satellite navigationsensor 180. As systems such as RTK systems are widely known the beacon sensor andthe satellite sensor will hereafter be discussed as being the same sensor.
The work area 205 is in this application exemplified as a garden, but canalso be other work areas as would be understood. The garden contains a number ofobstacles (O), exemplified herein by a number (3) of trees (T), a rock (R), a slope (S)and a house structure (H). The trees are marked both with respect to their trunks (filledlines) and the extension of their foliage (dashed lines).
As can be seen in figure 2, the boundary wire 220 has been laid so that so-called islands are formed around the trees" trunks and the house (H). This requires thatmore boundary wire is used, than if the work area was without such obstacles. It shouldbe noted that any distances between wires are greatly exaggerated in this application inorder to make the distances Visible in the drawings. In a real-life installations theboundary wire is usually laid so that there is not distance between the wire going outand the wire coming back (distance = 0). This allows the robotic work tool 100 to crossany such sections as the magnetic field emitted by the wire going out cancels out themagnetic field emitted by the wire coming back.
The work area 205 is in this application exemplified as a garden, but canalso be other work areas as would be understood. The garden contains a number ofobstacles (O), exemplified herein by a slope (S), a rock (R), a number (3) of trees (T)and a house structure (H). The trees are marked both with respect to their trunks (filledlines) and the extension of their foliage (dashed lines).
In some embodiments the robotic work tool is arranged or configured totraVerse and operate in a work area that is not essentially flat, but contains terrain that isof Varying altitude, such as undulating, comprising hills or slopes or such. The groundof such terrain is not flat and it is not straightforward how to determine an anglebetween a sensor mounted on the robotic work tool and the ground. The robotic worktool is also or altematively arranged or configured to traVerse and operate in a work areathat contains obstacles that are not easily discemed from the ground. Examples of suchare grass or moss coVered rocks, roots or other obstacles that are close to ground and of a similar colour or texture as the ground. The robotic work tool is also or altematively 12 arranged or configured to traverse and operate in a work area that contains obstacles thatare overhanging, i.e. obstacles that may not be detectable from the ground up, such aslow hanging branches of trees (T) or bushes. Such a garden is thus not simply a flatlawn to be mowed or similar, but a work area of unpredictable structure andcharacteristics. The work area 205 exemplified with referenced to figure 2, may thus besuch a non-uniforrn work area as disclosed in this paragraph that the robotic work tool isarranged to traverse and/or operate in. This is an example of a work area or gardenwhere some robotic lawnmowers are configured to work within.
The work area may also comprise a passage P that leads from one area ofthe work are 205 to another area. The passage need not be a specific corridor, or path,but can be any part of the work area that is narrow compared to the width of the roboticwork tool. The passage is shown in figure 3 as having straight and parallel sides, but itshould be noted that the sides of the passage may have any shape or form.
It should be noted that even though the teachings herein will be mainlyexemplified and discussed as relating to traversing a passage, they may also be appliedto general traversal of a part of a work area, especially work areas with uneven orirregular sides, or even a whole work area.
Figure 3 shows a schematic view of a passage P of a general work area 205.As mentioned above, the passage P may represent any part of a work area. The passagehas two sides Sl, S2 and two ends EPl and EP2.
The robotic work tool l00 is configured to follow a side at a given distanced utilizing the magnetic sensors l70. This is achieved by comparing the signal strengthreceived by two or more sensors l70 as is known to a skilled person. This provides foran accurate deterrnination of the distance d to the boundary wire 230 assumingly beinglaid in or close to the corresponding side. In one embodiment the boundary wire is laidat the distance from the side, whereby the robotic work tool following the side t thedistance is actually following the boundary wire at a 0 distance.
Figure 4 shows a flowchart of a general method according to the teachingsherein. A manner of operating a robotic work tool l00 according to the teachings herein will be described with simultaneous reference to figures 3 and 4. 13 In figure 3 a novel and beneficial Operating path is indicated by the dashedarrows. The robotic work tool 100 is configured to traverse through and operate within apassage P (also applicable to other parts of the work area) by following 410 a first sideat a first distance. And, as the robotic work tool 100 deterrnines 420 that an endEP1/EP2 of the passage P has been reached, the robotic work tool tums around 430 andfollows 440 the first side S1 at a second or next distance d (a next distance indicating alap where the robotic work tool follows the side farther away from the side than theprevious distance). It should be noted that only the second distance d is specificallymarked in the figure to not clutter the illustration, but it would be clear to a skilledperson that the other distances are clearly illustrated even if not being specificallyreferenced.
This is repeated at next distances until the robotic work tool 100 deterrnines450 that it is at or in a middle M of the passage P. The middle M may be defined as aline or as an area. More details on this will be discussed in the below. As it isdeterrnined 450 that the robotic work tool 100 is in the middle and it is deterrnined 455that an end EP1, EP2 of the passage P is reached, the robotic work tool tums around,proceeds 460 to the other or second side S2 of the passage P and follows 470 the secondside S2 at the first distance and then at a next distance 480, which procedure is repeateduntil the robotic work tool reaches the middle M again 485 upon which time the roboticwork tool 100 optionally leaves 490 the passage P or perforrns another task.
Such a systematic traversal of the passage (or other work area) has thebenefits that it ensures a sufficient and proper operation in the area, as all of it iscovered, without risking that the robotic work tool 100 is not able to perform any tums(as the tums are made in the open areas at the ends of the passage).
As a skilled person would notice when observing figure 3, there may besome overlap of a work tool, such as a cutting blade, in the middle which area may beserviced twice or doubly. In some embodiments the robotic work tool 100 is thusconfigured to operate at least partially overlapping in the middle of the passage to ensure that the middle is properly covered. In figure 3 this is specifically illustrated by the schematic representations of two cutting discs" circumference referenced Cl and C2.
As can be seen, the two circumferences (may) overlap in the middle. Likewise, by 14 increasing the distances d by an amount smaller than or equal to a circumference of awork tool, such as a cutting disc, a sufficient operation in the area can be ensured, suchas through an overlap between passings (laps of following a side).
As discussed in the above, the robotic work tool 100 may be configured todetermine that an end of a passage has been reached in different manners. The use ofmagnetic sensors may not give enough of an indication as they basically only give adistance to a boundary wire. However, the robotic work tool 100 may utilize a deducedreckoning navigation sensor 180, a beacon navigation sensor 190, a satellite navigationsensor 190 possibly in combination with a beacon navigation sensor to determine alocation relative an end point. As such sensors may not be as accurate as the magneticsensors when it comes to deterrnining an exact location or distance, they maybeneficially be used in combination with the magnetic sensors, where the magneticsensors 170 are used to ensure that an accurate distance to the side is maintained (eitheralone or supplementing the navigation sensors) while the navigation sensors 180/ 190(alone or in combination) are used to determine that an end of the passage P is reachedpossibly in combination with a map application stored in the memory 120 of the roboticwork tool 100. As this does not require the same accuracy the navigation sensors maybe used beneficially even if not being able to provide a high accuracy.
The robotic work tool 100 is in some embodiments further arranged todetermine that it is at or in the middle M of the passage utilizing the navigation sensorspossibly in combination with a map application stored in the memory 120 of the roboticwork tool 100. IN an altemative or supplemental embodiment the robotic work tool 100is arranged to determine that it is at or in the middle M of the passage utilizing themagnetic sensors 170. If two (or more) sensors are arranged at different distances to aboundary wire, such as the two front sensors 170-1, 170-2 of the robotic work tool 100in figure 1B will be when following the side as in figure 3, the two sensors will receivesignals from the boundary wire 220 at both sides S1, S2 at the same time, but atdifferent signal levels. As the sides S1, S2 are comparatively close to one another(compared to the speed of light), the two signals will be seen as the same signal by amagnetic sensor 170. However, - in the example of figure 3 and where the robotic work tool 100 is in the first illustrated location L1, the magnetic sensor closest to the first side SI (i.e sensor 170-I in figure IB), will receive a higher signal strength than the othersensor (i.e sensor 170-2 in figure IB). Whereas at the second location indicated L2 theopposite signal strengths will be received, where sensor 1702 in figure IB will receive ahigher signal strength than sensor 170-1. By comparing a first signal strength receivedby a first sensor (for example 170-I in this illustrative descriptive example) with asecond signal strength received by a second sensor (for example 170-2) it is possible todetermine which side of the middle the robotic work tool 100 is. As the relationshipchanges, the robotic work tool has crossed the middle M.
As the robotic work tool may tum and have a different sensor closer to theseide than before the tum, the robotic work tool need keep track of which side of therobotic work tool is closest to the side at any given time, such as through a tum, or atleast when following a side, to know how to differentiate between a tuming and acrossing of the middle, as the relationship between received signal strengths will changein both instances. The robotic work tool 100 is thus configured in some embodiments toadapt the deterrnination or comparison of received signal strengths based on whichsensor is closest to the side being followed. In some embodiments, the adaptation isdone at each tum. In some embodiments the adaptation is based on the deducedreckoning navigation sensor 180.
Figure 5A shows an altemative passage, where the sides S1, S2 are notparallel. In the example of figure 5A the sides are not even the same. As can be seen,the robotic work tool is still able to cover the whole area without missing any portionsby first following one side, from the side and in towards the middle M, and thenfollowing the other side, from the side and in towards the middle M by successivelyincreasing the distance the side S1, S2 is followed at.
In the example of figure 5A there will be a portion in the middle whereoperation may not be effectively provided (as indicated by the circumferences C 1, C2not overlapping). To avoid such situations the robotic work tool 100 is, in someembodiments, configured to provide an additional following or lap in the middle. This isillustrated in figure 5B where the additional lap is marked by a thicker line.
In some embodiments, the robotic work tool 100 is configured to perform an additional lap at the end of the second traversal as in figure 5B. In some embodiments, 16 the robotic work tool 100 is configured to perform an additional lap at the end of thefirst traversal. And, in some embodiments, the robotic work tool 100 is configured toperform an additional lap both at the end of the first traversal and at the end of thesecond traversal.
The robotic work tool 100 is in some embodiments configured to deterrnineto make an additional lap based on the shape of the side. If the side is irregularly shape(such as having a sideways extension and/or a total turning radius (accumulatedtumings) exceeding a threshold level, an additional lap is perforrned. The deterrninationmay be made at the end of each traversal (i.e as it is deterrnined that the middle M isreached), at the end of the first traversal, or at the end of the last traversal.
A traversal here being the laps performed up until it is deterrnined that themiddle has been reached, possibly including the last lap.
Figure 6A shows a schematic illustration of a passage having two sides, S1and S2, where four zones Zl-Z4 are indicated by dashed lines. Figure 6B shows a graphof the received signal strength P as a graph based on distance from a side. Theouterrnost zones, Zl, Z4 indicate an area close to the side or rather boundary wire wherethe received signal strength starts to drop. As is known to a skilled person the receivedsignal undergoes a polarity shift as a sensor passes a wire emitting the signal. To be ableto do this a drastic drop in signal strength is perceived close to the wire and in this area,the received signal is unreliable. The robotic work tool is therefore configured in someembodiments to stay out of the outerrnost zones, or at least not to perform the laps(follow the boundary in those zones, unless following the wire by straddling the wire).Therefore, the smallest (first) distance d at which the robotic work tool 100 follows aside, should be larger than the width (as in indicating a distance falling outside) of theouterrnost zones Zl, Z4. In one embodiment, the first distance d at which the roboticwork tool 100 follows a side is 20, 30 or 40 cm. Altematively the first distance d atwhich the robotic work tool 100 follows a side is 0 (straddling the wire). In someembodiments the successive or next distances are increased by 20, 30, 40 or 50 cm.
The innerrnost zones Z2 and Z3 indicate an area on each side of the middleof the passage where the received signal strength is relatively stable. It should be reminded that the received signal strength is the sum of the signal emitted from the first 17 side Sl and the signal emitted from the second side S2. Where the power line crossesthe horizontal axis indicates the position of the two sides/boundary wires S l, S2.
As discussed above, the robotic work tool is able to detect a passage fromzone 2 Z2 to zone 3 Z3 that is a crossing of the middle M, by detecting a shift in thereceived signal strength of two sensors placed at different distances from the side(s). Iffor example a first sensor l70-l is placed closer to the first side Sl, than a secondsensor 170-2 is, which in tum is placed closer to the second side S2, and the roboticwork tool is in zone 2 Z2, the robotic work tool will be able to determine that the middlehas been reached or rather crossed by deterrnining that the signal strength received bythe first sensor is no longer larger than the signal strength received by the secondsensor. The robotic work tool is thus able to determine that the robotic work tool has crossed into zone 3.

Claims (18)

1. 1. A robotic work tool (100) configured to operate in a work area (205), therobotic work tool (100) comprising a controller (110) configured to cause the robotic work tool to follow (410) a first side (S1) of the work area(205) at a distance for the first side (S1); deterrnine (420) that an end (EP1, EP2) has been reached and in responsethereto cause the robotic work tool to make a turn (430) and follow (440) the first side(S1) of the work area (205) at a next distance; deterrnine that a middle (M) has been reached (450) and in response theretocause the robotic work tool to proceed to a second side (S2) and follow (470) the secondside (S2) of the work area (205) at a first distance for the second side (S2); deterrnine that an end (EP1, EP2) has been reached and in response theretocause the robotic work tool to make a turn and follow (480) the second side (S2) of the work area (205) at a next distance.
2. The robotic work tool (100) according to claim 1, wherein the controller(110) is further configured to cause the robotic work tool to proceed to second side (S2)after it is deterrnined (455) that an end is reached.
3. The robotic work tool (100) according to claim 1 or 2 comprising a firstmagnetic sensor (170-1) and a magnetic sensor second (170-2), wherein the controller(110) is further configured to deterrnine that the middle (M) is reached based on comparing a signalstrength received by the first magnetic sensor (170-1) and a signal strength received by the second magnetic sensor (170-2).
4. The robotic work tool (100) according to any preceding claim, whereinthe controller (110) is further configured to repeat following the first side (S1) and/or the second side (S2) at a nextdistance until it is deterrnined that the middle (M) is reached.
5. The robotic Work tool (100) according to any preceding claim, Whereinthe controller (110) is further conf1gured to perforrn an additional lap as the middle (M) is reached.
6. The robotic Work tool (100) according to claim 5, Wherein the controller(110) is further conf1gured to perforrn an additional lap as the middle (M) is reachedfrom the first side (S1).
7. The robotic Work tool (100) according to claim 5 or 6, Wherein thecontroller (110) is further conf1gured to perform an additional lap as the middle (M) is reached from the second side (S2).
8. The robotic Work tool (100) according to claim 5, 6 or 7, Wherein thecontroller (110) is further configured to determine Whether to perform the additional lap or not based on a shape of the first side (S1) and/or a shape of the second side (S2).
9. The robotic Work tool (100) according to any preceding claim comprisinga satellite navigation sensor (190), Wherein the controller (110) is further conf1gured to determine that the end is reached based on the satellite navigation sensor (190).
10. The robotic Work tool (100) according to any preceding claimcomprising a deduced reckoning navigation sensor (180), Wherein the controller (110) isfurther configured to determine that the end is reached based on the deduced reckoning navigation sensor (180).
11. 1 1. The robotic Work tool (100) according to any preceding claim, Wherein the first distances are smaller than the next distances.
12. The robotic Work tool (100) according to any preceding claim, Wherein the first distances are the same.
13. The robotic Work tool (100) according to any preceding claim, Whereinthe first distance is larger than a zone Where a signal strength is reduced due to a polarity change (Z1, Z4).
14. The robotic Work tool (100) according to any preceding claim, Whereinthe next distance is increased by an amount smaller than or equal to the Width of a Work tool comprised in the robotic Working tool (100).
15. The robotic Work tool (100) according to any preceding claim, Whereinthe Work area (205) comprisesterrain that is of Varying altitude;obstacles that are not easily discemed from the ground; and/or obstacles that are oVerhanging.
16. The robotic Work tool (100) according to any preceding claim, Wherein the robotic Work tool (100) is a robotic lawnmower
17. The robotic Work tool (100) according to any preceding claim, Whereinthe first side (S1) and/or second side (S2) is a side of a passage (P) comprised in theWork area (205).
18. A method for use in a robotic Work tool (100) configured to operate in aWork area (205), the method comprising following (410) a first side (S1) of a Work area (205) at a distance for thefirst side (Sl); deterrnining (420) that an end (EPl, EP2) has been reached and in responsethereto making a tum (430) and following (440) the first side (S1) of the Work area(205) at a next distance;deterrnining that a middle (M) has been reached (450) and in responsethereto proceeding to a second side (S2) and following (470) the second side (S2) of theWork area (205) at a first distance for the second side (S2); deterrnining that an end (EPl, EP2) has been reached and in responsethereto make a turn and follow (480) the second side (S2) of the Work area (205) at a next distance.
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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007109624A2 (en) * 2006-03-17 2007-09-27 Irobot Corporation Robot confinement
EP2703925A1 (en) * 2011-04-28 2014-03-05 Positec Power Tools (Suzhou) Co., Ltd Automatic working system, automatic walking device and steering method thereof
EP2806325A2 (en) * 2013-04-09 2014-11-26 F. Robotics Acquisitions Ltd. Domestic robotic system and robot therefor
WO2016000734A1 (en) * 2014-06-30 2016-01-07 Husqvarna Ab Improved robotic working tool
US20160174459A1 (en) * 2014-12-22 2016-06-23 Irobot Corporation Robotic Mowing of Separated Lawn Areas
WO2017123137A1 (en) * 2016-01-11 2017-07-20 Husqvarna Ab A method and a system for navigating a self-propellered robotic tool
WO2017198222A1 (en) * 2016-05-19 2017-11-23 苏州宝时得电动工具有限公司 Automatic work system, self-moving device and control method therefor
WO2018182478A1 (en) * 2017-03-28 2018-10-04 Husqvarna Ab Improved perimeter marking for a robotic working tool
US20190025851A1 (en) * 2017-07-21 2019-01-24 AI Incorporated Polymorphic path planning for robotic devices
WO2020143972A1 (en) * 2019-01-08 2020-07-16 Husqvarna Ab A robotic tool, and methods of navigating and defining a work area for the same
WO2020199592A1 (en) * 2019-04-01 2020-10-08 珠海市一微半导体有限公司 Method for controlling robot to return to base

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE79967T1 (en) * 1985-10-15 1992-09-15 Knepper Hans Reinhard METHOD AND ARRANGEMENT FOR AUTOMATIC CONTROL OF A WORK VEHICLE.
JP4999965B2 (en) * 2010-06-04 2012-08-15 中国電力株式会社 Automatic cultivation method and automatic cultivation system
SE540131C2 (en) * 2014-12-24 2018-04-10 Husqvarna Ab Robotic work tool with trajectory correction

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007109624A2 (en) * 2006-03-17 2007-09-27 Irobot Corporation Robot confinement
EP2703925A1 (en) * 2011-04-28 2014-03-05 Positec Power Tools (Suzhou) Co., Ltd Automatic working system, automatic walking device and steering method thereof
EP2806325A2 (en) * 2013-04-09 2014-11-26 F. Robotics Acquisitions Ltd. Domestic robotic system and robot therefor
WO2016000734A1 (en) * 2014-06-30 2016-01-07 Husqvarna Ab Improved robotic working tool
US20160174459A1 (en) * 2014-12-22 2016-06-23 Irobot Corporation Robotic Mowing of Separated Lawn Areas
WO2017123137A1 (en) * 2016-01-11 2017-07-20 Husqvarna Ab A method and a system for navigating a self-propellered robotic tool
WO2017198222A1 (en) * 2016-05-19 2017-11-23 苏州宝时得电动工具有限公司 Automatic work system, self-moving device and control method therefor
WO2018182478A1 (en) * 2017-03-28 2018-10-04 Husqvarna Ab Improved perimeter marking for a robotic working tool
US20190025851A1 (en) * 2017-07-21 2019-01-24 AI Incorporated Polymorphic path planning for robotic devices
WO2020143972A1 (en) * 2019-01-08 2020-07-16 Husqvarna Ab A robotic tool, and methods of navigating and defining a work area for the same
WO2020199592A1 (en) * 2019-04-01 2020-10-08 珠海市一微半导体有限公司 Method for controlling robot to return to base

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