PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(51) International Patent Classification 7 :
`
`
`
`G05D 1/02
`
`(11) International Publication Number:
`
`WO 00/38025
`
`29 June 2000 (29.06.00)
`
`(43) International Publication Date:
`
`(21) International Application Number:
`
`PCT/GB99/04072
`
`(22) International Filing Date:
`
`6 December 1999 (06.12.99)
`
`(30) Priority Data:
`98277775
`
`18 December 1998 (18.12.98)
`
`GB
`
`(71) Applicant (for all designated States except US): NOTETRY
`LIMITED [GB/GB]; Kingsmead Mill, Little Somerford,
`Wiltshire SN15 5JN (GB).
`'
`
`(72) Inventors; and
`(75) Inventors/Applicants (for US only): BISSET, David, Lindsey
`[GB/GB]; 4 Chandler Way, Chippenham, Wiltshire SN15
`3YG (GB). ALDRED, Michael, David [GB/GB]; 16 Suther-
`land Cresent, Cepen Park North, Chippenham, Wiltshire
`SN14 6RS (GB).
`
`(74) Agents: SMITH, Gillian, Ruth et al.; Dyson Research Limited,
`P.O. Box 2080, Malmesbury, Wiltshire SN16 OSW (GB).
`
`(81) Designated States: AE, AL, AM, AT, AU, AZ, BA, BB, BG,
`BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK, DM, EE,
`ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP,
`KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA,
`MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU,
`SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG,
`US, UZ, VN, YU, ZA, ZW, ARIPO patent (GH, GM, KE,
`LS, MW, SD, SL, SZ, TZ, UG, ZW), Eurasian patent (AM,
`AZ, BY, KG, KZ, MD, RU, TJ, TM), European patent (AT,
`BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU,
`MC, NL, PT, SE), OAPI patent (BF, BJ, CF, CG, CI, CM,
`GA, GN, GW, ML, MR, NE, SN, TD, TG).
`
`Published
`With international search report.
`
`(54) Title:
`
`IMPROVEMENTS IN OR RELATING TO FLOOR CLEANING DEVICES
`
`
`
`
`
`(57) Abstract
`
`A robotic floor cleaning device is arranged so that it firstly completes a traverse around the edge of a room (A—I), avoiding any
`obstacles in its path, and then moves inwards (at I) and completes a second traverse of the room. The cleaning device continues to move
`inwards after each traverse (e.g. at T) so as to travel in a generally inwardly spiral manner until the floor of the room, apart from areas
`occupied by obstacles (400, 402), has been cleaned. Preferably, the distance by which the cleaning device moves inwardly after each
`traverse of the room is substantially the width of the cleaning head of the cleaning device, or a distance set by the user. The cleaning device
`seeks a wall of the room if it is started from a position (W) away from a wall. The cleaning device can determine when it has completely
`traversed a room.
`
`Silver Star Exhibit 1010
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`
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`Silver Star Exhibit 1010
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`

`

`Zimbabwe
`
`Albania
`Armenia
`Austria
`Australia
`Azerbaijan
`Bosnia and Herzegovina
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`COte d’Ivoire
`Cameroon
`China
`Cuba
`Czech Republic
`Germany
`Denmark
`Estonia
`
`ES
`FI
`FR
`GA
`GB
`GE
`GH
`GN
`GR
`HU
`IE
`IL
`IS
`IT
`JP
`KE
`KG
`KP
`
`Spain
`Finland
`France
`Gabon
`United Kingdom
`Georgia
`Ghana
`Guinea
`Greece
`Hungary
`Ireland
`Israel
`Iceland
`Italy
`Japan
`Kenya
`Kyrgyzstan
`Democratic People‘s
`Republic of Korea
`Republic of Korea
`Kazakstan
`Saint Lucia
`Liechtenstein
`Sri Lanka
`Liberia
`
`LS
`LT
`LU
`LV
`MC
`MD
`MG
`MK
`
`ML
`MN
`MR
`MW
`MX
`NE
`NL
`NO
`NZ
`PL
`PT
`RO
`RU
`SD
`SE
`SG
`
`Lesotho
`Lithuania
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`The former Yugoslav
`Republic of Macedonia
`Mali
`Mongolia
`Mauritania
`Malawi
`Mexico
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.
`
`SI
`SK
`SN
`SZ
`TD
`TG
`TJ
`TM
`TR
`TT
`UA
`UG
`US
`UZ
`VN
`YU
`ZW
`
`Slovenia
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Turkmenistan
`Turkey
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`Viet Nam
`Yugoslavia
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`Silver Star Exhibit 1010 - 2
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`Silver Star Exhibit 1010 - 2
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`WO 00/38025
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`PCT/GB99/04072 _
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`INIPROVEMENTS IN OR RELATING TO
`
`FLOOR CLEANING DEVICES
`
`5
`
`This invention relates to a robotic floor cleaning device, a method of operating a robotic
`
`floor cleaning device, and to software and a control apparatus for performing the method.
`
`The invention can be used in a robotic vacuum cleaning device.
`
`There have been a number of proposals to provide robotic or autonomous vacuum cleaning
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`10
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`devices which can clean a floor area without the need for a human user to push or drag the
`
`cleaning device along the floor.
`
`It is known to provide vacuum cleaners which are fed a
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`detailed map of a room and which are then trained to reciprocate to and fro from one side
`
`or one end of a room to the other side or other end of the room. It is also known to provide
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`a robotic vacuum cleaner which is lead around a room in a training cycle and which will
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`15
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`then repeat the cycle from information stored in memory. A robotic vacuum cleaner has
`
`also been proposed which travels round the edge of a room and then moves about the room
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`in a random fashion deflecting off obstacles as it moves around.
`
`DE 35 36 974 Al shows a floor cleaning device which performs a spiralling path over a
`surface to be cleaned.
`It requires a wetor dust trail to be deposited on the surface to be
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`20
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`cleaned in order that the machine can follow this spiral path.
`
`The present invention seeks to provide a robotic vacuum cleaner which minimises or
`
`overcomes disadvantages with the prior art.
`
`In particular, the present invention seeks to
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`25
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`provide a robotic vacuum cleaner that can cover a floor area without the need for advance
`
`knowledge of the layout of thefloor area and which does not leave a trail on the floor.
`
`A first aspect of the present invention provides method of operating a robotic floor
`
`cleaning device so that the floor cleaning device:
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`30
`
`(a)
`
`firstly completes a traverse around the edge of a room (or around a feature of the
`
`Silver Star Exhibit 1010 - 3
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`Silver Star Exhibit 1010 - 3
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`WO 00/38025
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`PCT/GB99/04072 _
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`2
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`room or an object in the room) avoiding any obstacles in its path, monitoring and storing
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`information from detectors during the traverse, and
`
`(b)
`
`when it is determined that monitored information from detectors is the same or
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`substantially the same as previously stored information, the floor cleaning device moves
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`inwards (or outwards) and completes a second traverse, the cleaning device continuing to
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`move inwards (or outwards) after each traverse so as to travel in a generally inwardly (or
`
`outwardly) spiral manner until
`
`the floor of the room, apart from areas occupied by
`
`obstacles, has been cleaned.
`
`Another aspect of the invention provides a robotic floor cleaning device comprising: power
`
`operated means for moving the cleaning device along the floor, and a navigation system,
`
`including sensors and a memory means, for navigating the cleaning device around the
`
`room, the navigation system being arranged to: (a) firstly cause the cleaning device to
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`complete a traverse around the edge of a room (or around a feature of the room or an
`
`object in the room) avoiding any obstacles in its path, monitoring and storing information
`
`from the sensors in the memory during the traverse, and (b) when it is determined that
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`monitored information from the sensors is the same or substantially the same as previously
`
`stored information, cause the device to move inwards (or outwards) and complete a second
`
`traverse,
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`the device continuing to move inwards (or outwards) after each completed
`
`traverse so as to travel in a generally inwardly (or outwardly) spiral manner until the floor
`
`of the room, apart from areas occupied by obstacles, has been cleaned.
`
`By following a spiralling pattern, the floor cleaning device can cover the complete floor
`
`area in an efficient manner. This method has the advantage that the floor cleaning device
`
`does not need to be programmed with advance lmowledge of the layout of the floor area,
`
`or the need to maintain a cartesian map of the floor area. This can simplify the processing
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`requirements of the controller of the cleaning device and avoids the need for a user to train
`
`the device or to load and update a map of the floor area that the device is to clean. Thus,
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`the cleaning device can easily cope with different room layouts.
`
`It also does not require
`
`the cleaning device to leave a trail on the floor during the cleaning operation so that the
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`10
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`15
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`30
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`Silver Star Exhibit 1010 - 4
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`Silver Star Exhibit 1010 - 4
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`WO 00/38025
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`PCT/GB99/04072 _
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`device can determine where it has previously travelled within the room.
`
`Each further step inwards (or outwards) occurs when a comparison of monitored
`
`information from the sensors with previously stored information indicates that the present
`
`U1
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`position of the cleaning device is the same, or almost the same, as a position that the
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`cleaning device has visited on the same circuit.
`
`A further problem with known robotic floor cleaning devices that have no advance
`
`knowledge of the layout of the floor area that they are cleaning is that they are incapable of
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`10
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`determining when they have completely traversed the floor area. By performing an
`
`inwardly spiralling coverage pattern of the floor area,
`
`the cleaning device progresses
`
`methodically towards the centre of the room. The cleaning device can determine when it
`
`has reached the middle of the room. One way for determining when the cleaning device
`
`has completely traversed a floor area is to associate stored information from each traverse,
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`15
`
`or circuit, of the floor area into strands and to determine when the strands converge,
`
`indicating that the floor area has been completely traversed. Any stored data which is
`
`not part of a strand that has converged is indicative of a part of the floor area that has
`
`not been completely traversed.
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`20
`
`The navigation system of the cleaning device can store information about the direction at
`
`which the cleaning device turns at each of the points where it stores sensor information.
`
`This can be used on later circuits to help the cleaning device in deciding which way to
`turn.
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`25
`
`The floor cleaning device carries a cleaner head or other cleaning mechanism that is
`
`generally of the same or similar width as the cleaning device.
`
`It will be appreciated that
`
`the stepping inwardly or outwardly during the spiralling method is based upon the
`
`effective width of the cleaning mechanism carried by the cleaning device so that the floor
`
`area is properly covered. Preferably the stepping distance is substantially one width of the
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`30
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`cleaner head, or slightly less than one width of the cleaner head so that each traverse
`
`slightly overlaps with the previous traverse. This ensures full coverage of the floor area
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`Silver Star Exhibit 1010 - 5
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`Silver Star Exhibit 1010 - 5
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`wo 00/38025
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`PCT/GB99/04072 ,
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`4
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`with the cleaning device travelling a minimum distance in a minimum length of time. This
`
`is an important concern with a cordless device that is capable of operating for a limited
`
`time, the operating time being dictated by the capacity of the on—board power supply.
`
`However, other stepping distances can be used where a more thorough cleaning of the
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`5
`
`floor area is required. Preferably, the stepping distance can be selected by a user of the
`
`cleaning device.
`
`The navigation system can be implemented entirely in hardware, in software running on a
`
`processor, or a combination of these. It can also be implemented as an application specific
`
`10
`
`integrated circuit (ASlC). Accordingly, further aspects of the present invention provide
`
`software and a control apparatus for operating the cleaning device in the manner described
`
`herein. The software is conveniently stored on a machine—readable medium such as a
`
`memory device.
`
`15
`
`Embodiments of the present invention will now be described, by way of example only,
`
`with reference to the accompanying drawings, in which:—
`
`Figure 1 shows a perspective view of one embodiment of a robotic cleaning
`
`device;
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`20
`
`Figure 2 shows a side view of the cleaning device of Figure 1;
`
`Figure 3 shows a rear view of the cleaning device of Figure 1;
`
`25
`
`Figure 4 shows the cleaning device in a typical room and the measurements
`
`made by sensors on the device;
`
`Figure 5 schematically shows the control systems of the cleaning device of
`
`Figure l;
`
`30
`
`Figures 6A and 6B show the cleaning device navigating around a room;
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`Silver Star Exhibit 1010 - 6
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`Silver Star Exhibit 1010 - 6
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`WO 00/38025
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`PCT/GB99/04072 _
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`Figure 7 shows a flow diagram of the method of controlling the cleaning device
`
`to navigate around a room in the manner shown in Figure 6;
`
`Figure 8 shows the features of ultrasonic sensor measurements which are stored;
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`Figure 9 shows the comparison of light detector measurements;
`
`Figure 10 shows a flow diagram of steps to store light detector measurements;
`
`Figures 11A and 11B show two ultrasonic sensor measurements;
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`Figure 12 shows a flow diagram of steps for comparing ultrasonic sensor
`
`measurements.
`
`Figure 13 shows the software architecture for the cleaning device;
`
`Figures 14 to 17 show the cleaning device navigating around floor areas having
`
`different layouts.
`
`Figure 1 of the drawings shows a robotic, or autonomous, floor cleaning device in the form
`
`of a robotic vacuum cleaner 100 comprising a main body or supporting chassis 102, two
`
`chiven wheels 104, a brushbar housing 122, two rechargeable batteries 161 and 162, a dust
`separating apparatus in the form of a dual cyclonic separator 152 of the type more fully
`
`described in EP-A—0042723, a user interface 144, a light detector 17 and various sensors
`
`202, 204, 206, 208, 210, 220, 230, 240, 250 which will be more fully described. The light
`
`detector 17 detects light received from a plurality of compass points around the vacuum
`
`cleaner and is more particularly described in our co-pending International Patent
`
`Application No. [our reference GBPOO99].
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`10
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`25
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`30
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`Silver Star Exhibit 1010 - 7
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`Silver Star Exhibit 1010 - 7
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`WO 00/38025
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`PCT/GB99/04072 _
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`6
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`The supporting chassis 102 is generally circular in shape and is supported on the two
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`driven wheels 104 and a castor wheel (106, Fig. 3). The chassis 102 is preferably
`
`manufactured from high—strength moulded plastics material, such as ABS, but can
`
`equally be made from metal such as aluminium or steel. The chassis 102 provides
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`5
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`support for the components of the cleaner 100. The driven wheels 104 are arranged at
`
`either end of a diameter of the chassis 102, the diameter lying perpendicular to the
`
`longitudinal axis of the cleaner 100. Each driven wheel 104 is moulded from a high—
`
`strength plastics material and carries a comparatively soft, ridged band around its
`
`circumference to enhance the grip of the wheel 104 when the cleaner 100 is traversing a
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`10
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`smooth floor. The soft, ridged band also enhances the ability of the wheels 104 to
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`mount and climb over small obstacles.
`
`The driven wheels 104 are mounted
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`independently of one another via support bearings (not shown) and each driven wheel
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`104 is connected directly to a motor (43, Figure 5) which is capable of driving the
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`respective wheel 104 in either a forward direction or a reverse direction. A full range of
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`15
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`manoeuvres are possible by independently controlling each of the traction motors 43.
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`By driving both wheels 104 forward at the same speed, the cleaner 100 can be driven in
`
`a forward direction. By driving both wheels 104 in a reverse direction at the same
`
`speed, the cleaner 100 can be driven in a backward direction. By driving the wheels
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`104 in opposite directions, the cleaner 100 can be made to rotate about its own central
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`20
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`axis so as to effect a turning manoeuvre. The aforementioned method of driving a
`
`vehicle is well known and will not therefore be described any further here.
`
`Mounted on the underside of the chassis 102 is a cleaner head 122 which includes a
`
`suction opening facing the surface on which the cleaner 100 is supported. A brush bar
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`25
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`is rotatably mounted in the suction opening and a motor (not shown) is mounted on the
`
`upper surface of the cleaner head 122 for driving the brush bar. The cleaner head 122 is
`
`mounted on the chassis 102 in such a way that the cleaner head 122 is able to float on
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`the surface to be cleaned. This is achieved in this embodiment in that the cleaner head
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`122 is pivotally connected to an arm (not shown) which in turn is pivotally connected to
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`30
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`the underside of the chassis 102. The double articulation of the connection between the
`
`cleaner head 122 and the chassis 102 allows the cleaner head to move freely in a vertical
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`Silver Star Exhibit 1010 - 8
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`Silver Star Exhibit 1010 - 8
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`WO 00/38025
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`PCT/GB99/04072 _
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`7
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`direction with respect to the chassis 102. This enables the cleaner head to climb over
`
`small obstacles such as books, magazines, rug edges, etc. A flexible or telescopic
`
`conduit is located between a rear portion of the cleaner head 122 and an inlet port
`
`located in the chassis 102.
`
`The cleaner head 122 is asymmetrically mounted on the chassis 102 so that one side of
`
`the cleaner head 122 protrudes beyond the general circumference of the chassis 102.
`
`This allows the cleaner 100 to clean close to the edge of a room on the side of the
`
`cleaner 100 on which the cleaner head 122 protrudes.
`
`In this embodiment the cleaner
`
`head 122 protrudes from the left—hand side of the cleaning device 100.
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`The chassis 102 carries a plurality of sensors which are designed and arranged to detect
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`obstacles in the path of the cleaner 100 and its proximity to, for example, a wall or other
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`boundary such as a piece of furniture. The sensors comprise several ultrasonic sensors
`
`and several infra-red sensors. The array of sensors will be described in more detail
`
`below.
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`The vacuum cleaner 100 also includes a motor and fan unit 150 supported on the chassis
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`102 for drawing dirty air into the vacuum cleaner 100 via the suction opening 124 in the
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`cleaner head 122. The cyclonic separator 152 separates dirt and dust from the air drawn
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`into the cleaner 100. The cyclonic separator 152 is releasable from the chassis 102 in
`
`order to allow emptying of the cyclonic separator 152. Two battery packs 161, 162 are
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`located on the chassis 102 on either side of the cyclonic separator 152.
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`The vacuum cleaner 100 described above operates in the following manner. In order for
`
`the cleaner 100 to traverse the area to be cleaned, the wheels 104 are driven by the
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`motors 105 which, in turn, are powered by the batteries 161, 162.
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`. The direction of
`
`movement of
`
`the cleaner 100 is determined by the control' software which
`
`communicates with the sensors which are designed to detect any obstacles in the path of
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`the cleaner 100 so as to navigate the cleaner 100 around the area to be cleaned. The
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`normal forward direction of the cleaner 100 is such that the cleaner head 122 trails
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`Silver Star Exhibit 1010 - 9
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`Silver Star Exhibit 1010 - 9
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`WO 00/38025
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`PCT/GB99/04072 _
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`8
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`behind the driven wheels 104. The battery packs 161, 162 also power the motor and fan
`
`unit 150 which draws air into the cleaner 100 via the cleaner head 122 and passes it to
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`the cyclonic separator 152 where the dirt and dust is separated from the airflow. The
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`battery packs 161, 162 are also used to power the motor which drives the brush bar
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`5
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`which, in turn assists with pick~up, particularly on carpets. The air which exits the
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`cyclonic separator 152 is passed across the motor and fan unit 150 by appropriate
`
`ducting.
`
`The sensor array forming part of the vacuum cleaner 100 will now be described in more
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`10
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`detail. The array comprises a plurality of ultrasonic sensors and a plurality of infra—red
`
`sensors. The majority of the sensors are located in a forward surface 180 of the vacuum
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`cleaner 100. The forward surface 180 is substantially semi—circular in plan View.
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`Further sensors are located at the uppermost extremity of the cleaner 100, at the rear of
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`the cleaner 100, immediately over the brush bar 122, and on the underside of the cleaner
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`15
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`100.
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`The robotic vacuum cleaner is also equipped with a plurality of infra-red transmitters 210a,
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`220, 226, 230a and infra-red receivers 225, a plurality of ultrasonic transmitters 202a,
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`204a, 206a, 208a and ultrasonic receivers 202b, 204b, 206b, 208b, threshold detectors (95,
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`20
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`Fig. 5) for detecting the presence of a portable threshold locator placed, for example, at the
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`entrance to a room or at the edge of a staircase and one or more pyroelectric or passive
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`infra—red (PIR) detectors 240a, 24Gb for detecting heat sources near to the cleaning device,
`
`such as animals and fires. The four main ultrasonic receivers 202b, 204b, 206b, 208b face
`
`forwards, rearwards and to opposite sides of the robotic vacuum cleaner. The signals
`
`25
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`received by these receivers not only provide information representative of distance from a
`
`feature of the room or from an object in the room but the amplitude and width of the
`
`received signals vary according to the sensed size, shape and type of material of the object.
`
`Three of the ultrasonic sensors 202, 204 and 206, each consisting of an ultrasonic
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`30
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`emitter and an ultrasonic receiver, are positioned in the forward surface 180. A first of
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`the ultrasonic sensors 202, comprising an emitter 202a and a receiver 202b, is directed
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`Silver Star Exhibit 1010 - 10
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`Silver Star Exhibit 1010 - 10
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`WO 00/38025
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`PCT/GB99/04072 _
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`9
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`in a forward direction so that the emitted signals are transmitted in the normal forward
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`direction of travel of the cleaner 100. A second ultrasonic sensor 204, comprising an
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`emitter 204a and a receiver 204b,
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`is directed such that
`
`the emitted signals are
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`transmitted outwardly to the left of the cleaner 100 in a direction which is perpendicular
`
`U!
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`to the direction of transmission by the ultrasonic sensor 202. A third ultrasonic sensor
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`206, comprising an emitter 206a and a receiver 206b, is directed such that the emitted
`
`signals are transmitted outwardly to the right of the cleaner 100 in a direction which is
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`perpendicular to the direction of transmission by the ultrasonic sensor 202 and opposite
`
`to the direction of transmission by the ultrasonic sensor 204. A fourth ultrasonic sensor
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`10
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`208, comprising ‘an emitter 208a and a receiver 208b, is located in the rear of the cleaner
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`100 (see Figure 3) and is directed rearwardly so that the emitted signals are transmitted
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`parallel to the normal forward direction of travel of the cleaner 100 but in the opposite
`
`direction.
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`These four sensors 202, 204, 206, 208 detect the presence of walls and
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`obstacles to the front, left, right and rear of the cleaner 100.
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`15
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`The infra—red sensors provide a curtain of coverage around the forward face 180 of the
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`cleaning device 100 which serve to prevent the cleaning device 100 from colliding with
`
`an obstacle, the infra—red sensors helping to fill-in any blind spots in the ultrasonic
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`sensor coverage and to detect obstacles that the ultrasonics cannot. The ultrasonic
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`20
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`sensors provide more accurate distance information about the environment around the
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`cleaning device and it is the ultrasonic data that is stored by the cleaning device for later
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`comparison.
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`Figures 4A and 4B show what information the device receives from its sensors. The
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`25
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`Figures show the cleaning device 100 in a room that contains the obstacles of a table 400
`
`and sofa 402. Figure 4A shows the light compass measurements. The cleaning device
`
`measures, using its light compass 17, light received from eight different directions (L1, L2,
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`L3, L4, L5, L6, L7, L8). This combination of measurements has generally been found to
`
`be unique within a given room to within an area of several widths of the cleaning device.
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`30
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`The room in Figure 4A is illuminated by a combination of natural light from a window 702
`
`and an artificial source 700. Light from the sources is reflected by objects 400, 402 and
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`Silver Star Exhibit 1010 - 11
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`Silver Star Exhibit 1010 - 11
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`walls of the room before it reaches the light compass 17 on the cleaning device.
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`addition to the light compass 17, the cleaning device also has the set of ultrasonic sensors
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`202, 204, 206, 208. Figure 4B shows the same room, illustrating the measurements made
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`by the ultrasonic sensors. The ultrasonic sensors are shown located at the front, left, right
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`and back of the cleaning device. Each ultrasonic sensor emits a beam of ultrasound which
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`is reflected from multiple objects within the room. Each ultrasonic sensor provides a
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`signal U81, U82, U83, U84 which is indicative of the distance of objects from the
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`cleaning device. A combination of the light compass data Ll..L8 and ultrasonic sensor
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`data USl..US4 allows the cleaning device to uniquely identify its position within the room.
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`The circuit shown in Figure 5 comprises two rechargeable batteries 161, 162, a battery
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`and motor management system 41, a motor 50 for driving a suction fan, traction motors
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`43 for driving the left and right hand wheels 104 of the vacuum cleaner, a motor 28 for
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`driving the brush bar of the vacuum cleaner and processing circuitry 23, which includes
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`a microprocessor and field programmable gate arrays (FPGA). A user interface board
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`29 provides a plurality of user switches 75 by which a user can control the cleaning
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`device and a plurality of indicator lamps 76 by which the cleaning device can indicate to
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`the user. The user interface board also couples to the light detector 17, as the upper face
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`of the cleaning device provides the light detector with an unobstructed View of the
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`environment. The microprocessor and FPGA share tasks, with the FPGA mainly being
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`used to process data from the ultrasonic sensors, extracting the important information
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`from the signals received by the ultrasonic receivers. A communications bus 70 couples
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`the processing circuitry 23 to the battery and motor management system 512 and the
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`user interface board 29.
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`A non-volatile memory 96,;such as a ROM or FLASH ROM, stores the control
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`software, another memory 97 is used during normal operation of the device. The
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`movement control sensors described above are coupled to the processing circuitry 23.
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`Figures 6 and 7 illustrate one method of operating the robotic vacuum cleaner to clean a
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`room. The method causes the cleaner to traverse the room in a generally spiralling
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`Silver Star Exhibit 1010 - 12
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`Silver Star Exhibit 1010 - 12
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`manner. The cleaner is, typically, placed alongside a wall or freely in the room. Firstly, it
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`finds a room feature (step 300). Preferably this is a wall of the room or a major object or
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`feature in the room. Once it has found a room feature, the cleaning device then moves
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`forwardly along the edge of the room. This period is called the “perimeter scan”, as the
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`machine follows the perimeter of the room as closely as possible, the machine keeping the
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`wall (or other obstacle) close to the left—hand side of the machine. The machine keeps the
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`wall close to the left-hand side of the machine as this is the side from which the cleaner
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`head 122 protrudes. The various sensors on the cleaner detect obstacles in the room and
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`other room features, such as corners of a room and fireplaces, and the processing circuitry
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`23 navigates the robotic vacuum cleaner in order to avoid any such obstacles and to change
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`direction when a feature of a room is reached. At each change of direction caused by
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`reaching a feature of the room, the processing circuitry 23 stores information received
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`from the light detector 17 and also from the four main ultrasonic receivers 202b, 204b,
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`206b, 208b in memory 97. This is the information shown in figure 4. These points are
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`called “way points”. While the described embodiment uses readings from a light detector
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`and ultrasonic sensors, readings from other sensors can be used. The processing circuitry
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`may also store information on the direction in which the cleaner turns at each change of
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`direction. Each time a way point is reached the cleaner monitors the information received
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`from the light detector 17 and the four ultrasonic receivers 202b, 204b, 206b, 208b and
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`compares this with way point information previously stored (step 304). When the robotic
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`vacuum cleaner reaches a position in which the information received from the light
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`detector 17 and the four ultrasonic receivers 202b, 204b, 206b, 208b is the same or
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`substantially the same as information previously stored,
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`the processing circuitry 23
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`determines that the robotic vacuum cleaner has completed a traverse around the room (step I
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`306) and is programmed to cause the robotic vacuum cleaner to step inwards by
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`substantially one cleaner width. The processing circuitry 23 continues to store way point
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`information and compares the information received from the light detector 17 and the four
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`main receivers 202b, 204b, 206b, 208b with previously stored information (step 308). The
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`cleaner progresses around the room in a generally inwardly spiralling manner.
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`Silver Star Exhibit 1010 - 13
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`As shown in Figure 6A, the vacuum cleaner starts from Position A and moves along the
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`edge of the room in a clockwise direction. At Position B it senses the presence of the wall
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`in front of it and turns 900 to the right.
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`It will already know from the sensors that there is a
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`wall on its left hand side. The cleaner then continues until it reaches Position C when it
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`will sense the presence of the table and turns so as to run along the side of the table. The
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`cleaner is programmed to keep one side close to the nearest wall or obstacle or close to the
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`most recently covered circuit of the room. Thus, when it reaches Position D it will turn to
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`the left and move forwards along the front of the table until it reaches Position B when it
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`will turn again to the left until it reaches Position F. At Position F, it will sense the
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`presence of the wall in front of it and will turn to the right and proceed along the wall until
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`it reaches Position G.
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`It will then turn right and pass through Position H until it reaches
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`Position 1. At Position 1, the light detector 17 and the four ultrasonic receivers 202b, 204b,
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`206b, 208b will detect information which is the same or substantially the same as they
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`detected at Position B. At this point, the cleaner will move inwards by, or substantially by,
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`one cleaner width and will then continue to follow the initial traverse around the room, but
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`one cleaner width within that initial traverse, via way points I, K, L, M, N until it senses
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`the existence of the sofa at Position 0. The cleaning device generally follows the
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`perimeter of the room at a scan distance of one cleaner width from the wall.
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`It stops
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`whenever it reaches a corner, stopping at the scan distance from the wall. For example, the
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`cleaning device stops at position N as it is one cleaner width from the end wall. After
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`position 0 the cleaning device runs along the perimeter of the sofa until it reaches Position
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`R when it will again follow the initial traverse around the room. When the machine returns
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`to similar way points on different circuits, e.g. way points C and J, or G and N, information
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`on the two points is associated with one another in memory in order to build up an
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`information strand. This tells the cleaner that it has returned to a similar position in the
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`room. Strands should converge towards each other as the cleaning device progresses.
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`These strands can be used to determine when a room has been completely traversed. Any
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`waypoints which have not been associated with later waypoints are indicative of parts of
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`the room which have not been completely covered by the cleaning-device.
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`Figure 6A shows the cleaning device performing a perimeter scan and stopping at point I.
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`This is possible if the cleaning device periodically takes sensor readings and compares
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`them with stored readings. However, it is preferred that sensor readings are made and
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`compared when the cleaning device is forced to change direction. Figure 6B shows this
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`preferred method of operation. During the perimeter scan, the cleaning device continues
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`until it reaches position I’. The cleaning device stops at position I’ as it has reached the
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`end wall and needs to change direction. The cleaning