PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`
` (51) International Patent Classification 7 :
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`(11) International Publication Number:
`WO 00/38025
`
`GOSD 1/02
`
`(43) International Publication Date:
`
`29 June 2000 (29.06.00)
`
`
`
`(21) International Application Number: PCT/GB99/04072|(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).
`
`(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|Published
`[GB/GB]; 4 Chandler Way, Chippenham, Wiltshire SN15
`With international search report.
`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).
`
`
`
`(54) Title:
`
`IMPROVEMENTS IN OR RELATING TO FLOOR CLEANING DEVICES
`
` §
`
`R
`
`402
`
`0
`
`(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 (c.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 whenit 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
`TE
`IL
`
`Spain
`Finland
`France
`Gabon
`United Kingdom
`Georgia
`Ghana
`Guinea
`Greece
`Hungary
`Treland
`Tsrael
`Tceland
`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
`
`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
`T™
`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
`
`Silver Star Exhibit 1010 - 2
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`Silver Star Exhibit 1010 - 2
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`

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`WO 00/38025
`
`PCT/GB99/04072 _
`
`IMPROVEMENTSIN OR RELATING TO
`
`FLOOR CLEANING DEVICES
`
`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 numberof proposals to provide robotic or autonomous vacuum cleaning
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`10
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`devices whichcan clean a floor area without the need for a humanuser to push ordrag the
`
`cleaning device along the floor.
`
`It is known to provide vacuum cleaners which are fed a
`
`detailed map of a room and which are then trained to reciprocate to and fro from one side
`
`or one endof a room to the otherside or other end of the room. It is also knownto provide
`
`a robotic vacuum cleaner whichis lead around a room in a training cycle and which will
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`15
`
`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
`
`in a random fashion deflecting off obstacles as it moves around.
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`20
`
`DE 35 36 974 Al showsa floor cleaning device which performsa spiralling path over a
`surface to be cleaned.
`It requires a wet or dusttrail to be deposited on the surface to be
`cleaned in order that the machinecan followthis 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
`
`provide a robotic vacuum cleaner that can cover a floor area without the need for advance
`knowledgeofthe layout of thefloor area and which doesnotleavea 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:
`
`30
`
`
`
`(a) firstly completes a traverse around the edge of a room (or aroundafeature of the
`
`Silver Star Exhibit 1010 - 3
`
`Silver Star Exhibit 1010 - 3
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`

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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
`
`information from detectors during the traverse, and
`
`(b)
`
`when it is determined that monitored information from detectors is the same or
`
`substantially the same as previously stored information, the floor cleaning device moves
`inwards (or outwards) and completes a second traverse, the cleaning device continuing to
`move inwards (or outwards) after each traverse so as to travel in a generally inwardly (or
`
`outwardly) spiral manner until
`obstacles, has been cleaned.
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`10
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`the floor of the room, apart from areas occupied by
`
`Anotheraspect 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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`15
`
`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
`
`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,
`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 knowledge of the layout of the floor area,
`or the need to maintain a cartesian map ofthe floor area. This can simplify the processing
`requirements ofthe controller of the cleaning device and avoids the needfor a userto train
`
`20
`
`25
`
`the device or to load and update a mapofthe floor area that the device is to clean. Thus,
`the cleaning device can easily cope with different room layouts.
`It also does not require
`the cleaning deviceto leaveatrail on the floor during the cleaning operation so that the
`
`30
`
`Silver Star Exhibit 1010 - 4
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`Silver Star Exhibit 1010 - 4
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`

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`WO 00/38025
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`PCT/GB99/04072 _
`
`device can determine whereit has previously travelled within the room.
`
`on
`
`10
`
`15
`
`Each further step inwards (or outwards) occurs when a comparison of monitored
`information from the sensors with previously stored information indicates that the present
`position of the cleaning device is the same, or almost the same, as a position that the
`cleaning device hasvisited on the samecircuit.
`
`A further problem with known robotic floor cleaning devices that have no advance
`knowledge of the layoutof the floor area that they are cleaningis that they are incapable of
`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 whenit
`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,
`
`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 convergedis 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.
`
`25
`
`30
`
`The floor cleaning device carries a cleaner head or other cleaning mechanism that is
`generally of the same orsimilar 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 distanceis substantially one width of the
`cleaner head, orslightly 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
`
`Silver Star Exhibit 1010 - 5
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`Silver Star Exhibit 1010 - 5
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`

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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
`
`floor area is required. Preferably, the stepping distance can be selected by a user of the
`
`cleaning device.
`
`Thenavigation system can be implementedentirely in hardware, in software running on a
`
`processor, or a combination of these. It can also be implemented as an application specific
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`10
`
`integrated circuit (ASIC). 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,
`
`20
`
`Figure 2 showsa side view ofthe cleaning device of Figure 1;
`
`Figure 3 showsa rear view of the cleaning device of Figure 1;
`
`25
`
`Figure 4 showsthe 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 1;
`
`30
`
`Figures 6A and 6B showthe cleaning device navigating around a room;
`
`Silver Star Exhibit 1010 - 6
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`Silver Star Exhibit 1010 - 6
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`

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`WO 00/38025
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`PCT/GB99/04072 _
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`Figure 7 showsa flow diagram of the methodof controlling the cleaning device
`
`to navigate around a room in the manner shownin Figure 6;
`
`Figure 8 showsthe features of ultrasonic sensor measurements whichare stored;
`
`Figure 9 shows the comparisonoflight detector measurements;
`
`Figure 10 showsa flow diagram ofsteps to store light detector measurements;
`
`Figures 11A and 11B show twoultrasonic sensor measurements;
`
`Figure 12 shows a flow diagram of steps for comparing ultrasonic sensor
`
`measurements.
`
`Figure 13 showsthe 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 showsa robotic, or autonomous, floor cleaning device in the form
`
`of a robotic vacuum cleaner 100 comprising a main body or supporting chassis 102, two
`
`driven 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. Thelight
`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 GBP0099}.
`
`10
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`15
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`20
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`25
`
`30
`
`Silver Star Exhibit 1010 - 7
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`Silver Star Exhibit 1010 - 7
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`

`

`WO 00/38025
`
`PCT/GB99/04072
`
`6
`
`The supporting chassis 102 is generally circular in shape and is supported on the two
`
`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
`
`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 enhancethe grip of the whee] 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
`
`independently of one another via support bearings (not shown) and each driven wheel
`
`104 is connected directly to a motor (43, Figure 5) which is capable of driving the
`
`respective wheel 104 in either a forward direction or a reverse direction. A full range of
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`15
`
`manoeuvres are possible by independently controlling each of the traction motors 43.
`
`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
`
`104 in opposite directions, the cleaner 100 can be madeto rotate about its own central
`
`20
`
`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
`is rotatably mounted in the suction opening and a motor (not shown) is mounted on the
`
`25
`
`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 waythat the cleaner head 122is able to float on
`
`the surface to be cleaned. This is achieved in this embodimentin that the cleaner head
`
`122 is pivotally connected to an arm (not shown) which in turn is pivotally connected to
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`30
`
`the underside of the chassis 102. The double articulation of the connection between the
`
`cleaner head 122 andthe chassis 102 allows the cleaner head to movefreely in a vertical
`
`Silver Star Exhibit 1010 - 8
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`Silver Star Exhibit 1010 - 8
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`

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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 embodimentthe cleaner
`
`10
`
`head 122 protrudes from theleft-hand side of the cleaning device 100.
`
`The chassis 102 carries a plurality of sensors which are designed and arranged to detect
`
`obstacles in the path of the cleaner 100 and its proximity to, for example, a wall or other
`
`boundary such as a piece of furniture. The sensors comprise several ultrasonic sensors
`
`15
`
`and several infra-red sensors. The array of sensors will be described in more detail
`
`below.
`
`The vacuum cleaner 100 also includes a motor and fan unit 150 supported on the chassis
`
`102 for drawing dirty air into the vacuum cleaner 100 via the suction opening 124 in the
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`20
`
`cleaner head 122. The cyclonic separator 152 separates dirt and dust from the air drawn
`
`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
`
`located on the chassis 102 on either side of the cyclonic separator 152.
`
`25
`
`30
`
`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
`motors 105 which, in turn, are powered by the batteries 161, 162.
`. The direction of
`
`the cleaner 100 is determined by the control software which
`movement of
`communicates with the sensors which are designed to detect any obstacles in the path of
`the cleaner 100 so as to navigate the cleaner 100 around the area to be cleaned. The
`
`normal forward direction of the cleaner 100 is such that the cleaner head 122 trails
`
`Silver Star Exhibit 1010 - 9
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`Silver Star Exhibit 1010 - 9
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`

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`WO 00/38025
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`PCT/GB99/04072 _
`
`8
`
`behind the driven wheels 104. The battery packs 161, 162 also power the motor and fan
`unit 150 which drawsair into the cleaner 100 via the cleaner head 122 and passesit to
`
`the cyclonic separator 152 where the dirt and dust is separated from the airflow. The
`
`battery packs 161, 162 are also used to power the motor which drives the brush bar
`
`which, in turn assists with pick-up, particularly on carpets. The air which exits the
`
`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
`
`10
`
`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
`
`cleaner 100. The forward surface 180 is substantially semi-circular in plan view.
`Further sensors are located at the uppermost extremity of the cleaner 100, at the rear of
`
`the cleaner 100, immediately over the brush bar 122, and on the underside of the cleaner
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`15
`
`100.
`
`The robotic vacuum cleaneris also equipped with a plurality of infra-red transmitters 210a,
`
`220, 226, 230a and infra-red receivers 225, aplurality of ultrasonic transmitters 202a,
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`204a, 206a, 208a and ultrasonic receivers 202b, 204b, 206b, 208b, threshold detectors (95,
`
`Fig. 5) for detecting the presence of a portable threshold locator placed, for example,at the
`entrance to a room orat the edge of a staircase and one or more pyroelectric or passive
`infra-red (PIR) detectors 240a, 240b for detecting heat sources near to the cleaning device,
`such as animals and fires. The four mainultrasonic receivers 202b, 204b, 206b, 208b face
`
`forwards, rearwards and to opposite sides of the robotic vacuum cleaner. The signals
`
`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.
`
`20
`
`25
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`Three of the ultrasonic sensors 202, 204 and 206, each consisting of an ultrasonic
`emitter and an ultrasonic receiver, are positioned in the forward surface 180. A first of
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`30
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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
`
`direction of travel of the cleaner 100. A second ultrasonic sensor 204, comprising an
`emitter 204a and a receiver 204b,
`is directed such that
`the emitted signals are
`
`transmitted outwardlyto the left of the cleaner 100 in a direction which is perpendicular
`to the direction of transmission by the ultrasonic sensor 202. A third ultrasonic sensor
`
`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
`
`perpendicularto 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) andis directed rearwardlyso that the emitted signals are transmitted
`parallel to the normal forward direction of travel of the cleaner 100 but in the opposite
`direction.
`These four sensors 202, 204, 206, 208 detect the presence of walls and
`
`obstacles to the front, left, right and rear of the cleaner 100.
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`15
`
`The infra-red sensors provide a curtain of coverage around the forward face 180 ofthe
`
`cleaning device 100 whichserve 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
`
`sensor coverage and to detect obstacles that the ultrasonics cannot. The ultrasonic
`
`sensors provide more accurate distance information about the environment around the
`
`cleaning device andit is the ultrasonic data that is stored by the cleaning device for later
`
`comparison.
`
`Figures 4A and 4B show what information the device receives from its sensors. The
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`25
`
`Figures show the cleaning device 100 in a room that contains the obstacles of a table 400
`
`and sofa 402. Figure 4A showsthe light compass measurements. The cleaning device
`measures, usingits light compass 17, light received from eight different directions (L1, L2,
`L3, LA, 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.
`The room in Figure 4Ais 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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`30
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`Silver Star Exhibit 1010 - 11
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`Silver Star Exhibit 1010 - 11
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`wo 00/38025
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`PCT/GB99/04072 _
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`10
`
`In
`walls of the room before it reaches the light compass 17 on the cleaning device.
`addition to the light compass 17, the cleaning device also has the set of ultrasonic sensors
`
`202, 204, 206, 208. Figure 4B shows the same room,illustrating the measurements made
`by the ultrasonic sensors. The ultrasonic sensors are shownlocated atthe front,left, right
`and back of the cleaning device. Each ultrasonic sensor emits a beam of ultrasound which
`
`is reflected from multiple objects within the room. Each ultrasonic sensor provides a
`signal USI, US2, US3, US4 which is indicative of the distance of objects from the
`cleaning device. A combination of the light compass data L1..L8 and ultrasonic sensor
`data US1..US4 allowsthe cleaning device to uniquely identify its position within the room.
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`10
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`15
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`20
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`25
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`The circuit shown in Figure 5 comprises two rechargeable batteries 161, 162, a battery
`and motor management system 41, a motor 50 for driving a suction fan, traction motors
`
`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
`a microprocessor and field programmable gate arrays (FPGA). A user interface board
`29 provides a plurality of user switches 75 by which a user can control the cleaning
`device and a plurality of indicator lamps 76 by which the cleaning device can indicate to
`the user. The user interface board also couplesto the light detector 17, as the upperface
`of the cleaning device provides the light detector with an unobstructed view of the
`environment. The microprocessor and FPGAshare tasks, with the FPGA mainly being
`used to process data from the ultrasonic sensors, extracting the important information
`from the signals received by the ultrasonic receivers. A communications bus 70 couples
`the processing circuitry 23 to the battery and motor management system 512 and the
`user interface board 29.
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`A non-volatile memory 96,’such as a ROM or FLASH ROM,stores the control
`software, another memory 97 is used during normal operation of the device. The
`movementcontrol 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
`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 cleaneris, typically, placed alongside a wall or freely in the room. Firstly,it
`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. Onceit has found a room feature, the cleaning device then moves
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`forwardly along the edge of the room. This periodis called the “perimeter scan”, as the
`machine follows the perimeter of the room asclosely as possible, the machine keeping the
`wall (or other obstacle) close to the left-hand side of the machine. The machine keeps the
`wall close to the left-hand side of the machineas 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 processingcircuitry
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`23 navigates the robotic vacuum cleanerin order to avoid any such obstacles and to change
`direction when a feature of a room is reached. At each change of direction caused by
`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
`and ultrasonic sensors, readings from other sensors can be used. The processingcircuitry
`may also store information on the direction in which the cleaner turns at each change of
`direction. Each time a way pointis 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). Whenthe robotic
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`vacuum cleaner reaches a position in which the information received from the light
`detector 17 and the four ultrasonic receivers 202b, 204b, 206b, 208b is the same or
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`the processing circuitry 23
`substantially the same as information previously stored,
`determinesthat the robotic vacuum cleaner has completeda traverse around the room (step |
`306) and is programmed to cause the robotic vacuum cleaner to step inwards by
`substantially one cleaner width. The processing circuitry 23 continues to store way point
`information and compares the information received from the light detector 17 and the four
`main receivers 202b, 204b, 206b, 208b with previously stored information (step 308). The
`cleaner progresses aroundthe room in a generally inwardly spiralling manner.
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`Silver Star Exhibit 1010 - 13
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`Silver Star Exhibit 1010 - 13
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`WoO00/38025
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`PCT/GB99/04072 _
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`12
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`As shown in Figure 6A, the vacuum cleaner starts from Position A and movesalong the
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`edge of the room in a clockwise direction. At Position B it senses the presence of the wall
`in front of it and turns 90° to the right.
`It will already know from the sensorsthat 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 presenceofthe table and turns soas to run alongthe side of the table. The
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`cleaner is programmed to keep oneside 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 E whenit
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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 I. At Position I, 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
`detected at Position B. Atthis point, the cleaner will move inwards by, or substantially by,
`one cleaner width and will then continueto follow the initial traverse around the room, but
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`one cleaner width within that initial traverse, via way points J, K, L, M, N until it senses
`the existence of the sofa at Position O. The cleaning device generally follows the
`perimeter of the room at a scan distance of one cleaner width from the wall.
`It stops
`wheneverit reaches a corner, stopping at the scan distance from the wall. For example, the
`Cleaning device stops at position N as it is one cleaner width from the end wall. After
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`position O the cleaning device runs along the perimeter ofthe sofa until it reaches Position
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`R whenit 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
`on the two points is associated with one another in memory in order to build up an
`information strand. Thistells the cleaner that it has returned to a similar position in the
`room. Strands should converge towards each other as the cleaning device progresses.
`These strands can be used to determine when a room has been completely traversed. Any
`waypoints which have not been associated with later waypoints are indicative of parts of
`the room which have not been completely covered by the cleaning device.
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`Silver Star Exhibit 1010 - 14
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`Silver Star Exhibit 1010 - 14
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`WO 00/38025
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`Figure 6A showsthe cleaning device performing a perimeter scan and stopping at pointI.
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`This is possible if the cleaning device periodically takes sensor readings and compares
`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 showsthis
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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 device takes readings from its
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`sensors and makes a comparisonofthis new data with stored data and recognises that point
`I’ is the sameas pointB and that the cleaning device has therefore completed onecircuit of
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`the floor area. This causes the cleaning device to step inwardly to begin the next circuit of
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`the room.