`
`
`
`G05D 1/02
`
`
`
`(21) International Application Number:
`PCT/US99/ 16078
`
`
`
`(22) International Filing Date:
`16 July 1999 (16.07.99)
`
`
`(30) Priority Data:
`
`
`983057613
`20 July 1998 (20.07.98)
`EP
`
`PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`Intematlonal Bureau
`
`
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`
`
`(11) International Publication Number:
`
`WO 00/04430
`
`A1
`
`(43) International Publication Date:
`
`27 January 2000 (27.01.00)
`
`(81) Designated States: AE, AL, AM, AT, AT (Utility model), AU,
`AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, CZ
`(Utility model), DE, DE (Utility model), DK, DK (Utility
`model), EE, EE (Utility model), ES, FI, Fl (Utility model),
`GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE,
`KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG,
`MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE,
`SG, SI, SK, SK (Utility model), SL, TJ, TM, TR, TT, UA,
`UG, US, UZ, VN, YU, ZA, ZW, ARIPO patent (GH, GM,
`KE, LS, MW, SD, SL, SZ, 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.
`
`
`
`
`
`(71) Applicant (for all designated States except US): THE PROC-
`
`TER & GAMBLE COMPANY [US/US]; One Procter &
`Gamble Plaza, Cincinnati, OH 45202 (US).
`
`
`(72) Inventors; and
`
`
`
`(75) Inventors/Applicants (for US only):
`BOTTOMLEY,
`Ian
`[GB/GB];
`17 Howick Street, Alnwick, Northumberland
`
`
`NE66 IUZ (GB). COATES, David [GB/GB]; 14 Percy
`Road, Shilbottle, Northumberland NE66 2HF (GB). GRAY-
`
`
`DON, Andrew, Russell [GB/GB]; 42 The Wills Building,
`Wills Oval, Newcastle—upon—Tyne NE7 7RW (GB).
`
`
`(74) Agents: REED, T., David et al.; The Procter & Gamble
`Company, 5299 Spring Grove Avenue, Cincinnati, OH
`45217—1087 (US).
`
`
`
`(54) Title: ROBOTIC SYSTEM
`
`(57) Abstract
`
`A self—propelled robot is disclosed for movement over a surface to be treated. The robot has a power supply (ll) and a pair of
`wheels (8,9) driven by motors (6, 7) for moving the robot over the ssurface. A mechanism (113, 115, 16) is provided for controllably
`depositing a fluent material onto the surface. Navigation sensors (4, 13, 18, 21) provide signals for enabling the robot to navigate over
`the surface and one or more detectors (14, 15, 17) detect the presence of the material on the surface and provide signals indicative of its
`presence. A control system (100) receives the signals from the sensors and detectors and controls the motors and the depositing mechanism
`in dependence upon the signals received from the sensors and detectors.
`
`Silver Star Exhibit 1006
`
`
`
`
`Silver Star Exhibit 1006
`
`
`
`FOR THE PURPOSES OF INFORMATION ONLY
`
` AL
`
`AM
`AT
`AU
`AZ
`BA
`BB
`BE
`BF
`BC
`3.1
`BR
`BY
`CA
`CF
`CG
`CH
`CI
`CM
`CN
`CU
`CZ
`DE
`DK
`EE
`
`ES
`FI
`FR
`GA
`GB
`GE
`GH
`GN
`GR
`HU
`IE
`IL
`IS
`IT
`JP
`KE
`KG
`KP
`
`KR
`KZ
`LC
`LI
`LK
`LR
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.
`Slovenia
`SI
`Lesotho
`LS
`Slovakia
`LT
`SK
`Lithuania
`SN
`LU
`Senegal
`Luxembourg
`Swaziland
`SZ
`Latvia
`LV
`TD
`Chad
`MC
`Monaco
`TG
`MD
`Togo
`Republic of Moldova
`MG
`TJ
`Tajikistan
`Madagascar
`TM
`Turkmenistan
`MK
`The former Yugoslav
`TR
`Turkey
`Republic of Macedonia
`TT
`Mali
`Trinidad and Tobago
`UA
`Ukraine
`Mongolia
`UG
`Mauritania
`Uganda
`US
`United States of America
`Malawi
`UZ
`Uzbekistan
`Mexico
`VN
`Viet Nam
`Niger
`YU
`Netherlands
`Yugoslavia
`ZW
`Zimbabwe
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`
`Albania
`Armenia
`Austria
`Australia
`Azerbaijan
`Bosnia and Herzegovina
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`COte d’lvoire
`Cameroon
`China
`Cuba
`Czech Republic
`Germany
`Denmark
`Estonia
`
`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
`
`ML
`MN
`MR
`MW
`MX
`NE
`NL
`NO
`NZ
`PL
`PT
`RO
`RU
`SD
`SE
`SG
`
`
`
`Silver Star Exhibit 1006 - 2
`
`Silver Star Exhibit 1006 - 2
`
`
`
`WO 00/04430
`
`PCT/US99/16078
`
`ROBOTIC SYSTEM
`
`The present
`
`invention relates to robotic systems and,
`
`more particularly to a mobile robotic system capable of
`
`movement
`
`over
`
`a
`
`surface
`
`and
`
`capable
`
`of
`
`treating the
`
`surface.
`
`Conventionally robotic systems,
`
`or
`
`robots, of
`
`this
`
`type may
`
`be described as
`
`semi—autonomous,
`
`i.e.
`
`self-
`
`propelling
`
`but
`
`relying
`
`for
`
`navigational
`
`guidance
`
`on
`
`transmitters,
`
`receivers
`
`and
`
`sensors
`
`to
`
`establish
`
`a
`
`coordinate system by which the robot navigates,
`
`in effect
`
`learning the location of obstacles within its field of
`
`movement. More recently it has been proposed to allow a
`
`robot
`
`to move without establishing a coordinate system,
`
`instead relying on the sensing of ad hoc stimuli to enable
`
`the robot
`
`to navigate around obstacles.
`
`For example,
`
`it
`
`has been proposed to provide a
`
`robotic vacuum cleaner
`
`operating along these lines.
`
`Self-navigational
`
`robotic
`
`systems of this type are referred to as autonomous robots.
`
`However,
`
`robots of
`
`these types, often intended for
`
`operation in a domestic environment, need a control system
`
`which is capable of allowing the robot
`
`to move around its
`
`environment
`
`in safety and therefore additionally need some
`
`sort of collision detection system which is capable of
`
`providing information on collisions or impending collisions
`
`to a control
`
`system capable of acting very quickly to
`
`prevent the collision or else to minimise the impact,
`
`and
`
`to perform collision avoidance by re—orienting the robot
`
`before
`
`further
`
`movement.
`
`Unfortunately,
`
`on—board
`
`processing power
`
`is inevitably limited by cost constraints
`
`in particular and therefore present systems,
`
`to avoid be
`
`prohibitively
`
`expensive,
`
`have
`
`relatively
`
`limiting
`
`navigational abilities which result,
`
`in use,
`
`in the robot
`
`tracing a path which involves passing over
`
`the same areas
`
`of the surface on plural occasions. Whilst this may not be
`
`problematic in say a vacuum cleaner,
`
`if the robot has the
`
`Silver Star Exhibit 1006 - 3
`
`Silver Star Exhibit 1006 - 3
`
`
`
`WO 00/04430
`
`PCT/US99/16078
`
`function of treating the surface in other ways,
`
`then such
`
`redundant movement may
`
`result
`
`in over-treatment of
`
`the
`
`surface which is not only wasteful of the product used for
`
`the treatment
`
`(a
`
`serious problem where
`
`the payload is
`
`restricted), but may also damage the surface or otherwise
`
`actually be harmful.
`
`The present
`
`invention is aimed at providing a self-
`
`propelled robot which can overcome such problems.
`
`According to the present
`
`invention,
`
`there is provided
`
`a self—propelled robot for movement over a surface to be
`
`treated,
`
`the robot comprising
`
`a power supply;
`
`a traction mechanism receiving power
`
`from the power
`
`supply, for moving the robot over the surface;
`
`a mechanism for
`
`controllably depositing a
`
`fluent
`
`material on to the surface;
`
`a plurality of navigation sensors providing signals
`
`for enabling the robot to navigate over the surface;
`
`one or more detectors adapted to detect
`
`the presence
`
`of
`
`the material
`
`on
`
`the
`
`surface
`
`and
`
`provide
`
`signals
`
`indicative thereof; and
`
`a
`
`control
`
`system receiving the
`
`signals
`
`from the
`
`sensors
`
`and
`
`detectors,
`
`for
`
`controlling
`
`the
`
`traction
`
`mechanism and the depositing mechanism in dependence upon
`
`the signals received from the sensors and detectors.
`
`By detecting the application of
`
`the fluent material,
`
`which may be a liquid or gaseous fluid or else a flowable
`
`powder,
`
`the over-application of material can be avoided or
`
`minimised by either navigating the robot
`
`around
`
`areas
`
`already treated and/or
`
`by
`
`controlling the
`
`depositing
`
`mechanism to stop the deposit
`
`of material
`
`over
`
`such
`
`previously treated areas.
`
`Material for treatment
`
`is preferably contained within
`
`a
`
`reservoir
`
`on
`
`the
`
`robot
`
`and may
`
`comprise
`
`suitable
`
`compositions
`
`for
`
`treatment of
`
`floors,
`
`carpets
`
`and other
`
`floor coverings.
`
`The robot may,
`
`if desired, also include
`
`Silver Star Exhibit 1006 - 4
`
`Silver Star Exhibit 1006 - 4
`
`
`
`WO 00/04430
`
`PCT/US99/16078
`
`means
`
`for cleaning'
`
`the floor or
`
`floor covering' prior to
`
`treatment,
`
`for example in the form of
`
`a vacuum cleaning
`
`device.
`
`The
`
`invention also includes a method of
`
`treating a
`
`surface using a
`
`robot as defined above.
`
`The
`
`treatment
`
`method may be used for various applications on carpets, and
`
`other
`
`floor
`
`coverings,
`
`such
`
`as
`
`cleaning,
`
`protective
`
`treatment,
`
`for example for stain and soil protection, fire
`
`protection,
`
`UV protection, wear
`
`resistance,
`
`dust mite
`
`control, anti microbial
`
`treatment and the like, as well as
`
`treatment
`
`to
`
`provide
`
`an
`
`aesthetic
`
`benefit
`
`such
`
`as
`
`odorization/deodorization.
`
`The treatment method may also
`
`find application on other surfaces such as synthetic floor
`
`coverings,
`
`ceramics or wood.
`
`As well as polishing hard
`
`surfaces,
`
`the robot may also be used to apply coatings to
`
`either enhance aesthetics or to act as a protective layer.
`
`Thus, according to a further aspect of the invention,
`
`there is provided a method for controllably depositing a
`
`fluent material
`
`on to floors,
`
`carpets
`
`and other
`
`floor
`
`coverings using an autonomous, self propelled, deposition—
`
`sensing robot.
`
`The material deposited may, for example, be
`
`a carpet cleaning composition,
`
`a hard surface cleaning
`
`composition, or one of
`
`a number of compositions applied
`
`simultaneously, or successively, and may include a marker,
`
`the presence of which can be detected to provide detection
`
`of
`
`the extent of
`
`treatment material deposition.
`
`Such a
`
`marker may have a limited detection life,
`24 or 48 hours.
`
`for example, 12,
`
`Non~visible treatment may also be provided by
`
`the
`
`robot of
`
`the invention,
`
`for example,
`
`for odour control,
`
`antibacterial action of dust mite control.
`
`The
`
`robot
`
`preferably
`
`comprises
`
`a
`
`plurality
`
`of
`
`navigation sensors providing signals for enabling the robot
`
`to navigate over
`
`‘the surface,
`
`and one or more detectors
`
`adapted to detect
`
`the presence of
`
`the material
`
`on
`
`the
`
`surface
`
`and provide
`
`signals
`
`indicative
`
`thereof.
`
`The
`
`Silver Star Exhibit 1006 - 5
`
`Silver Star Exhibit 1006 - 5
`
`
`
`WO 00/04430
`
`PCT/U 599/16078
`
`navigation sensors may
`
`include
`
`one
`
`or more collision
`
`sensors and/or proximity sensors.
`
`The collision sensors
`
`may
`
`include
`
`one
`
`or more
`
`lateral
`
`displacement
`
`sensors
`
`arranged on
`
`a peripheral
`
`sensor
`
`ring to provide
`
`360‘”
`
`collision
`
`detection,
`
`and/or
`
`one
`
`or
`
`more
`
`vertical
`
`displacement sensors.
`
`Utilising a generally circular shape together with a
`
`control regime which scans for the best direction of escape
`
`after
`
`the robot has become
`
`stuck (say in a corner)
`
`especially
`
`advantageous.
`
`Furthermore,
`
`it
`
`may
`
`is
`
`be
`
`additionally advantageous
`
`to detect
`
`the
`
`angle of
`
`any
`
`collision,
`
`in order to optimise the robots subsequent angle
`
`of movement away from the obstacle.
`
`The
`
`traction, mechanism preferably includes
`
`left
`
`and
`
`right, coaxially disposed drive wheels with corresponding
`
`drive motors which are preferably provided with pulse-width
`
`modulated drive signals.
`
`For depositing material on the surface,
`
`an array of
`
`delivery ports, e.g.
`
`spray nozzles, may extend generally
`
`parallel with the drive wheel axis, preferably extending to
`
`the same lateral extent as the deposition detectors.
`
`The detectors may
`
`comprise
`
`one
`
`or more
`
`sensors
`
`arranged to detect
`
`the edge of
`
`a section of previously
`
`deposited product.
`
`Suitable deposition detectors include
`
`one or more radiation sources and/or detectors, moisture
`
`detectors,
`
`reflectivity meters,
`
`conductivity meters etc.
`
`Detectors may be disposed laterally of
`
`the drive wheels,
`
`preferably forward thereof.
`
`The
`
`robot
`
`further preferably comprises
`
`a
`
`control
`
`system for controlling deposition of the material dependent
`
`on the signals received from the one or more detectors and
`
`sensors.
`
`In preferred embodiments,
`
`the
`
`control
`
`system
`
`functions to control deposition of
`
`the material
`
`(e.g.
`
`to
`
`avoid or minimise over—application)
`
`by a combination of
`
`strategies
`
`comprising
`
`a)navigating
`
`the
`
`robot
`
`around
`
`previously-treated areas of the surface (referred to herein
`
`Silver Star Exhibit 1006 - 6
`
`Silver Star Exhibit 1006 - 6
`
`
`
`WO 00/04430
`
`PCT/US99/16078
`
`as
`
`the
`
`‘navigation strategy';
`
`and
`
`b)
`
`controlling the
`
`depositing mechanism to stop or
`
`reduce
`
`the deposit of
`
`fluent material on to the surface as the robot passes over
`
`such. previously-treated areas
`
`(referred to herein as
`
`the
`
`‘deposition rate control strategy').
`
`In practice,
`
`the
`
`control
`
`system arbitrates
`
`between
`
`the
`
`two
`
`strategies
`
`depending on
`
`the
`
`signals
`
`received from the navigation
`
`sensors
`
`and deposition detectors.
`
`The ability of
`
`the
`
`control system to arbitrate between the two strategies, for
`
`example to make
`
`a
`
`rapid judgment on whether
`
`to cross or
`
`navigate around previously-treated areas
`
`and whether
`
`to
`
`maintain,
`
`reduce or
`
`stop deposition accordingly,
`
`is an
`
`important feature for ensuring controlled deposition in the
`
`context of a fully autonomous robot designed to operate in
`
`the cluttered,
`
`unstructured and
`
`track—free
`
`environment
`
`typically found in domestic and institutional situations.
`
`Alternatively,
`
`the control system can be designed to
`
`control deposition purely following a deposition rate
`
`control
`
`strategy,
`
`in other words,
`
`by
`
`controlling the
`
`depositing mechanism to stop or
`
`reduce
`
`the deposit of
`
`fluent material on to the surface as the robot passes over
`
`previously—treated areas.
`
`Of
`
`course,
`
`systems depending
`
`purely on deposition rate control require less complicated
`
`electronics than the preferred combined-strategy systems
`
`described above.
`
`On
`
`the other hand,
`
`single strategy
`
`systems can be less efficient in terms of the time required
`
`to complete the task in hand.
`
`Preferably,
`
`the control
`
`system has
`
`a hierarchical
`
`architecture
`
`and
`
`includes
`
`one
`
`or more microprocessor
`
`controllers or microcontrollers
`
`for controlling higher-
`
`level
`
`functions,
`
`and providing higher-level
`
`instructions
`
`and a plurality of lower-level function modules adapted to
`
`receive signals
`
`from the sensors
`
`and detectors
`
`and to
`
`provide control signals in response thereto.
`
`The traction
`
`mechanism and
`
`product
`
`dispensing
`
`control
`
`signals
`
`are
`
`preferably issued to a traction mechanism controller and to
`
`Silver Star Exhibit 1006 - 7
`
`Silver Star Exhibit 1006 - 7
`
`
`
`WO 00/04430
`
`PCT/US99/16078
`
`a product dispensing controller via a manifold or bus
`
`arranged to receive signal
`
`inputs from the microprocessor
`
`and a plurality of sub~processors each corresponding to a
`
`respective navigation sensor or the like.
`
`By this means, a
`
`distributed processing system can be employed to provide a
`
`high level of
`
`flexibility in control
`
`strategy, whilst
`
`allowing simple connection of
`
`the sub-processors,
`
`thus to
`
`reduce the complexity and expense of
`
`the control
`
`system.
`
`The various processors preferably include neural network
`
`functionality
`
`to
`
`provide
`
`behavioural
`
`characteristics
`
`appropriate
`
`to
`
`the
`
`chosen
`
`task
`
`of
`
`the
`
`robot,
`
`the
`
`behavioural characteristics of
`
`the processors preferably
`
`being moderated by a group of generic moderators providing
`
`necessary arbitration between the control
`
`instructions from
`
`the
`
`various
`
`processors.
`
`The
`
`higher-level
`
`functions
`
`preferably include one or more
`
`functions
`
`selected from
`
`determination
`
`of
`
`the
`
`robot
`
`being
`
`stuck,
`
`room size
`
`estimation,
`
`clutter
`
`level
`
`determination,
`
`and
`
`battery
`
`monitoring.
`
`The lower-level modules are preferably analog
`
`neural networks which provide, for example, edge follow and
`
`dispense
`
`control
`
`functions,
`
`together,
`
`preferably, with
`
`Cliff
`
`sensing, collision detection,
`
`speed reduction and
`
`random movement functions.
`
`One example of a self-propelled robot constructed in
`
`accordance with the present
`
`invention,
`
`and its method of
`
`operation, will
`
`now be described with reference to the
`
`accompanying drawings in which:—
`
`Figure 1 is an underneath plan view of the robot;
`
`Figure 2 is a functional diagram of the robot; and
`
`Figures 3A-C illustrate neural net aspects of part of
`
`the robot's control system.
`
`As can be seen from Figure 1,
`
`the robot of the present
`
`example is substantially circular in overall plan view.
`
`A
`
`simple plate-like chassis J.
`
`supports both the mechanical
`
`and electrical components of
`
`the robot.
`
`The plate—like
`
`chassis 1 supports the body 2 of
`
`the robot on resilient
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`rubber mountings 3 which allow the body to move relative to
`
`the chassis when a force is applied,
`
`eg by collision with
`
`an object,
`
`to a sensor ring 20 which is disposed around the
`
`periphery of the body.
`
`Four displacement sensors 4 placed
`
`at
`
`90"
`
`intervals
`
`around
`
`the
`
`robot measure
`
`lateral
`
`displacement of
`
`the body 2 relative to the chassis 1 and
`
`inform the control
`
`system of contact with an external
`
`object.
`
`The. displacement sensors 4 are based on linear
`
`Hall Effect devices which produce
`
`a voltage which
`
`is
`
`proportional to the strength of the magnetic field in which
`
`they immersed.
`
`Each sensor consists of a small permanent
`
`magnet mounted on the body shell support ring 20 and a Hall
`
`Effect device mounted on the main chassis 1. When the body
`
`moves with respect
`
`to the chassis
`
`(as happens during a
`
`collision)
`
`the voltage produced by the Hall Effect device
`
`varies and can be used to signal the control system that an
`
`object has been encountered.
`
`By examining the signals from
`
`all four sensors the angle and magnitude of
`
`the collision
`
`can be deduced.
`
`These sensors allow displacements in the
`
`order of 0.1 mm to be reliably detected.
`
`A fifth sensor
`
`18,
`
`of
`
`the
`
`same
`
`type
`
`as
`
`the displacement
`
`sensors
`
`measures vertical
`
`displacement
`
`of
`
`the
`
`body
`
`shell
`
`accommodate
`
`forces
`
`produced
`
`by
`
`objects which
`
`are
`
`4,
`
`to
`
`of
`
`insufficient height to cause lateral body movement.
`
`In an
`
`alternative construction,
`
`these sensors may be superseded
`
`by a single custom-built sensor which can measure lateral
`
`and
`
`vertical
`
`displacement
`
`simultaneously.
`
`Such
`
`an
`
`integrated sensor may be optical
`
`in nature utilising an
`
`array of photo detectors mounted on the chassis and a light
`
`source which is mounted on the body support ring.
`
`A
`
`single
`
`forward
`
`facing time—of—flight ultrasound
`
`sensor 13 is mounted at the front of the robot and is used
`
`to allow the robot to gather more information regarding its
`
`surroundings
`
`than can
`
`be
`
`achieved by
`
`the displacement
`
`sensors 4 alone.
`
`This ultrasound sensor 13 is based on a
`
`Polaroid® ranging module Polaroid 6500 series sonar ranging
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`device, Polaroid reference 615077,
`
`the data from which is
`
`pre-processed by a dedicated unit 5 on which the sensor 13
`
`is located.
`
`An ultrasonic sensor unit 5, containing the
`
`ultrasonic sensor
`
`13
`
`itself
`
`and
`
`a
`
`suitable electronic
`
`interface, are mounted on the body to provide proximity
`
`information to the robot's control system.
`
`Left
`
`and right motors 6,
`
`7 are provided to drive
`
`corresponding left and right wheels 8,
`
`9 each with a soft
`
`rubber tyre, via an integral reduction gearbox,
`
`to provide
`
`motive power to the robot.
`
`A single castor 10 mounted at
`
`the rear of the robot completes the drive/movement system
`
`and allows the chassis to move
`
`forwards or backwards and
`
`rotate on the spot. Varying the rotational speed of
`
`the
`
`left and right motors 6,
`
`7 allows the robot
`
`to be steered
`
`in any direction.
`
`The speed of the motors is controlled by
`
`pulse width modulating the voltages applied to the motors.
`
`This involves switching the motor current on and off very
`
`rapidly (100,000 times a second)
`
`and varying the ratio of
`
`'on'
`
`time to 'off'
`
`time.
`
`This is a very efficient way to
`
`control the power to the motors and hence their speed.
`
`Power for the robot,
`
`including the motors 6, 7 and the
`
`control system is provided by means of a battery pack 11
`
`mounted on the chassis 1.
`
`To protect the components of the
`
`robot
`
`from ‘tampering and from damage a cover or housing
`
`(not
`
`shown)
`
`is attached to the body 2
`
`to house the robot
`
`components.
`
`In the preferred embodiment,
`
`this is part-
`
`spherical or dome-like in shape.
`
`A row of spray nozzles 16 and a pump 115 (not shown in
`
`Figure 1) provide a means of dispensing treating fluid on
`
`to 'the surface to be treated and detectors 14,15,17 are
`
`provided to detect the presence of the treating fluid (or a
`
`suitable additional marker fluid).
`
`The three sensor units
`
`14, 15, 17, one placed in front of each of the drive wheels
`
`and
`
`the
`
`third 17
`
`placed centrally,
`
`emit
`
`light at
`
`a
`
`wavelength which excites a fluorescent dye in the product
`
`being detected.
`
`These sensor units incorporate a pair of
`
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`light sensitive devices positioned at
`
`9O£3
`
`to the robot's
`
`direction of travel and spaced 20mm apart, which can detect
`
`light produced by the fluorescent dye.
`
`By examining the
`
`intensity of
`
`the light detected by these devices the edge
`
`of
`
`a
`
`section of previously deposited product
`
`can
`
`be
`
`detected
`
`and
`
`hence
`
`followed.
`
`In
`
`an
`
`alternative
`
`construction,
`
`the three sensor units 14,
`
`15,
`
`17 pass
`
`a
`
`small electrical current
`
`through the floor
`
`covering by
`
`virtue of an array of stainless steel contacts which are
`
`designed to glide over
`
`the floor covering surface.
`
`The
`
`conductivity of the floor covering will vary depending upon
`
`whether or not it has recently been sprayed with product.
`
`By examining the conductivity of
`
`the floor covering,
`
`the
`
`edge of previously deposited product can be detected and
`hence followed.
`
`In an alternative construction,
`
`in which fluid is to
`
`be dispensed to an edge or corner,
`
`the positioning of the
`
`sprays
`
`is modified.
`
`The modification is such that
`
`the
`
`spray is able to dispense to the edge of
`
`the robot or
`
`beyond,
`
`for example, either by positioning nozzles at the
`
`very periphery of
`
`the underside or by additional nozzles
`
`which protrude from the casing and are directed such that
`
`they spray beyond the perimeter of the robot.
`
`The robot's control
`
`system comprises various circuit
`
`boards and components which are not
`
`shown in Figure 1
`
`in
`
`detail,
`
`but which
`
`are broadly
`
`indicated by
`
`reference
`
`numerals 12 in Figure 1.
`
`The control
`
`system will now be described in further
`
`detail.
`
`Two purposes of
`
`the control
`
`system of an autonomous
`
`mobile robot such as that of the example are to allow the
`
`robot
`
`to move within a physical environment
`
`in safety and
`
`to enable it to perform useful tasks.
`
`To do this the robot
`
`must be aware of its immediate surroundings and be able to
`
`react
`
`to particular circumstances in particular ways.
`
`A
`
`robot
`
`intended for
`
`an unconstrained domestic environment
`
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`10
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`needs
`
`to have certain basic skills,
`
`such as a collision
`
`detection skill, which might
`
`cause
`
`it
`
`to stop
`
`upon
`
`collision with an object
`
`and then take evasive action
`
`before resuming its previous activity.
`
`In the case of collision detection,
`
`the sensors 4, 18,
`
`13, which sense impacts with and proximity to objects, will
`
`inform the control system of
`
`the angle of
`
`impact and its
`
`force.
`
`The control system must react very quickly to this
`
`stimulus and prevent any further motion in this direction.
`
`A conventional approach to this problem would be to have a
`
`computer monitor
`
`the collision sensors
`
`and act upon the
`
`data to stop the motors
`
`and then perform some
`
`form of
`
`avoidance manoeuvre.
`
`This
`
`is perfectly feasible, but
`
`if
`
`the same computer
`
`is required simultaneously to perform
`
`other
`
`tasks,
`
`for example,
`
`such as
`
`in the present case,
`
`monitoring
`
`other
`
`sensors
`
`and
`
`performing
`
`navigational
`
`mathematics,
`
`it soon reaches a point where the speed and
`
`power
`
`of
`
`the
`
`on-board
`
`computer
`
`required
`
`becomes
`
`prohibitively expensive
`
`if
`
`reaction times
`
`are
`
`to be
`
`acceptable.
`
`The alternative, adopted in the present
`
`invention,
`
`is
`
`to use discrete modules
`
`that perform functions in a way
`
`analogous to the reflexes of a biological organism.
`
`The
`
`advantage of
`
`this system are obvious:
`
`the main processor
`
`can merely issue high level commands such as move or turn
`and is left free to perform other abstract tasks.
`
`This alternative is a form of hierarchical distributed
`
`processing and allows the control system to be composed of
`
`simple modules
`
`that
`
`together yield faster response times
`
`than a non-distributed system of
`
`the same cost.
`
`Another
`
`significant
`
`advantage of distributed processing is
`
`its
`
`inherent robustness.
`
`If a system employing a conventional
`
`single processor approach suffers a failure,
`
`it can leave
`
`the system in an unsafe state, which in the case of a robot
`
`might allow it
`
`to crash into objects or people.
`
`The
`
`distributed approach can be designed so as to have a much
`
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`11
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`greater degree of fault tolerance,
`
`rendering the occurrence
`
`of complete system failures much less likely.
`
`Distributed
`
`processing
`
`can
`
`be
`
`implemented
`
`using
`
`conventional computers connected together by some
`
`form of
`
`network, but
`
`these tend to be expensive to design and
`
`implement.
`
`The approach adopted in the present
`
`invention
`
`is to simulate biological neural networks in real analogue
`
`hardware to provide a system that consists of behavioural
`
`modules, which are designed to perform individual
`
`tasks.
`
`These behaviours are managed by a simple micro controller,
`
`which performs higher
`
`level
`
`tasks
`
`such as mathematical
`
`functions to estimate room size or a strategy for escaping
`
`from under a table.
`
`The control
`
`system 100 will
`
`now be described with
`
`reference to Figures 2 and 3.
`
`Figure 2
`
`illustrates the
`
`functional relationship of the control system components.
`
`The control behaviours used on
`
`the
`
`robot
`
`can be
`
`divided into two basic types,
`
`Low Level
`
`and High Level.
`
`Low Level
`
`behaviours
`
`are
`
`implemented
`
`in
`
`hardware
`
`as
`
`discrete neural blocks or modules 101—105, while High Level
`
`behaviours
`
`are
`
`software
`
`algorithms
`
`running on
`
`a micro
`
`controller 106.
`
`The functions of the Low level behaviour modules 101-
`
`105 are now described in detail:—
`
`Cliff — To prevent the robot falling down stairs it is
`
`equipped with four cliff detectors 21 which warn of
`
`vertical hazards
`
`and provide signals
`
`to the cliff
`
`behaviour module 101.
`
`The cliff detectors
`
`21 are
`
`active infra red proximity sensors which comprise a
`
`modulated light source which emits a beam of infra red
`
`light directed at the target (in this case the floor),
`
`and an infra red detector which monitors the intensity
`
`of the light which is reflected. When the sensor is
`
`directed over a cliff the intensity of
`
`the reflected
`
`light decreases
`
`and the sensor
`
`informs
`
`the control
`
`system of
`
`the hazard.
`
`This behavioural
`
`function has
`
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`very
`
`high priority and when
`
`active
`
`operates
`
`to
`
`manoeuvre the robot away from the hazard and return it
`
`to a course which is modified to avoid cliff type
`
`drops.
`
`Edge Follow - The Edge Follow module 104 provides a
`
`behavioural
`
`function which uses
`
`information from the
`
`sensors 14,15,17 which allow the robot
`
`to find the
`
`edge of a previously treated area (as described above)
`
`and to travel along that edge to produce a faster scan
`
`of the floor surface.
`
`Random - In the absence of any edges the robot moves
`
`in a random direction under
`
`the action of
`
`a
`
`random
`
`movement module 114 until an object is encountered or
`
`the edge follow behaviour is activated.
`
`Collide - The collision detection module
`
`102
`
`takes
`
`input
`
`from the displacement sensors 4,18 and operates
`
`so that upon encountering an obstacle the robot stops,
`
`reverses a small distance,
`
`then turns away from the
`
`object
`
`in a direction that depends upon the angle of
`
`impact, which is determined from the signals of
`
`the
`
`displacement sensors 4,18.
`
`Reduce Speed - When
`
`an object
`
`is detected by
`
`the
`
`ultrasound sensor unit 5 within a pre-set range limit,
`
`the forward speed of
`
`the robot
`
`is reduced by the
`
`Reduce Speed module 103 to minimise the impact force
`
`generated when contact with the object occurs.
`
`Dispense - A dispense control module 105 has
`
`inputs
`
`from a fluid level sensor 203 and sensors 14, 15,
`
`17
`
`via the Edge Follow module 104.
`
`If the UV sensors 14,
`
`15,
`
`17
`
`report untreated carpet
`
`in the direction of
`
`travel
`
`the
`
`treatment
`
`chemical
`
`is
`
`dispensed until
`
`treated areas are encountered or fluid level reaches a
`
`lower limit.
`
`High
`
`level
`
`behaviours
`
`are
`
`determined within
`
`the
`
`microcontroller 106 and comprise the following functional
`
`modules:-
`
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`stuck - A routine 107 determines if there have been
`
`more than a chosen number of collisions in a select
`
`period and causes
`
`the robot
`
`to stop and use
`
`the
`
`ultrasound range finder 5,
`
`13
`
`to find the longest
`
`clear path and move in that direction.
`
`The robot will
`
`rotate on the spot, by operating the wheels 8,
`
`9
`
`in
`
`opposite directions,
`
`looking for
`
`the longest clear
`
`path. When the best direction is discovered the robot
`
`will move off in that direction.
`
`Estimate Room size - By using statistics gathered from
`
`the ultrasound sensor
`
`13
`
`and measuring
`
`the
`
`time
`
`between collisions the routine 108 is able to estimate
`
`the area of the room.
`
`This is used to determine how
`
`long the robot should take to treat a particular room.
`
`Estimate clutter
`
`level
`
`- By comparing estimates of
`
`room size against collisions per minute a routine 109
`
`is able to deduce a factor describing the complexity
`
`of the room.
`
`This can then be used to modify the run
`
`time to allow for the level of clutter.
`
`Battery Monitor - A battery monitor routine 110 checks
`
`the state of
`
`the battery by monitoring the output
`
`voltage and current.
`
`It uses
`
`this information to
`
`estimate how long the battery will be able to support
`
`the robot's systems before a
`
`re-charge is needed.
`
`When
`
`the monitor
`
`routine decides
`
`that
`
`the battery
`
`state
`
`is
`
`approaching
`
`the
`
`point where
`
`reliable
`
`operation is no longer possible,
`
`the user is warned by
`
`illumination of a battery low indicator.
`
`If the robot
`
`is
`
`allowed
`
`to continue
`
`to operate without
`
`being
`
`re—charged the monitor
`
`routine will
`
`shut
`
`the robot
`
`down
`
`in a
`
`safe and controlled fashion when
`
`power
`
`levels reach a predetermined point. Nickel Cadmium or
`
`Nickel Metal Hydride
`
`batteries
`
`require
`
`careful
`
`charging to ensure maximum capacity and life span and
`
`the monitor routine also controls the charging cycle
`
`of the battery to ensure that these needs are met.
`
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`14
`
`Traditionally neural network designers have insisted
`
`that every neuron in a network is connected to every other
`
`neuron in that network. Whilst this allows the network the
`
`greatest
`
`level of flexibility, very many (even as high as
`
`90%) of these connections will never be used.
`
`The present
`
`system allows
`
`pre-configured
`
`neural
`
`networks
`
`to
`
`be
`
`connected together in a much less complex way allowing the
`
`behaviour of
`
`the
`
`robot
`
`to dynamically
`
`adjust
`
`to the
`
`immediate environment in a continuous fashion.
`
`This
`
`so—called "Manifold Architecture"
`
`comprises
`
`an
`
`analogue bus or manifold 111, connecting all the behaviour
`
`modules
`
`101-105
`
`and their associated actuators
`
`to each
`
`other.
`
`Four generic moderators arbitrate between the
`
`behaviours, and give rise to a prototype behaviour of their
`
`own which regulates the overall activity of the robot via a
`
`motor controller 112 and dispensing fluid pump controller
`
`113 driving the pump 115.
`
`These generic moderators sum all
`
`the excitatory and inhibitory inputs and apply a non-linear
`
`transfer function to the results.
`
`The outputs from these
`
`moderators form the inputs to the motor controllers.
`
`In order
`
`to explain the function of
`
`the manifold
`
`architecture, it is necessary to describe the basic neural
`
`aspects of
`
`the control
`
`system.
`
`Figures
`
`3A—C will
`
`be
`
`referenced for this purpose.
`
`A single neuron (see Fig.
`
`3A) has three basic types of
`
`connections, excitatory inputs which cause the neuron to
`
`'fire',
`
`inhibitory inputs which suppress activity and the
`
`output