Accessory for a cleaning device
This invention relates to a barner for use with an autonomous cleaning device, apparatus for cleaning a floor surface and to a method of cleaning a floor area using an autonomous cleaning device
There has long been a desire for a vacuum cleaner which is capable of cleaning a room without the need for a human user to push or drag the cleaner around the room. A number of robotic or autonomous vacuum cleaners have been proposed and examples are shown in, inter aha, US 5,787,545 and WO 99/28800 The control mechanism for these cleaners include sensors for detecting obstacles and walls so that the vacuum cleaner is capable of guiding itself around a room so as to clean the carpet or other floor covenng without human intervention. While autonomous cleaners are generally capable of dealing with most rooms, there are certain limits on what such cleaners are capable of and autonomous cleaners have been known to struggle with certain types of obstacle in a room. One particularly problematic type of obstacle is the threshold to a descending stairway. Some autonomous cleaners have been sold with instructions not to use them in rooms having certain types of feature. Clearly, this limits the usefulness of an autonomous cleaner.
The present invention seeks to allow an autonomous cleaner to be used in rooms having a wider range of room features or obstacles.
Accordingly, a first aspect of the present invention provides a barner for use with an autonomous floor cleaning device to mark a threshold which the cleaning device should not cross, the barner compnsing a self-supporting structure having a surface which is capable of reflecting interrogatory radiation from distance sensors on the device back to the device.
The barner allows the cleaning device to be used in rooms having a much wider range of features or obstacles, such as the threshold to a descending stairway or a plant with
branches trailing onto the floor. Thus, the cleaning device can be used in more rooms of a user's home
Another aspect of the invention provides apparatus for cleaning a floor surface compnsmg. an autonomous floor cleaning device comprising a navigation system foi navigating the device around the floor surface, which system includes distance sensors which, in use, emit interrogatory radiation and receive reflected radiation from a surface so as to determine distance of the device from an obstacle; and a barner for marking a threshold which the cleaning device should not cross, the barner compnsmg a self- supporting structure having a surface which can reflect the interrogatory radiation from the distance sensors on the device back to the device
A further aspect of the invention provides a method of cleaning a floor area using an autonomous floor cleaning device, the method compnsmg: - marking a threshold which the autonomous cleaning device should not cross by placing a barner along the threshold; and
- operating the cleaning device to begin autonomously cleaning the floor area, the barner compnsmg a self-supporting structure having a surface which can reflect interrogatory radiation received from distance sensors on the device back to the device as the cleaning device moves around the floor area
The barπer can be used to mark a boundary around an obstacle that a user wishes the cleaning device to avoid, or it can be used to confine the cleaning device to a region of the room.
Embodiments of the present invention will now be descπbed, by way of example only, with reference to the accompanying drawings, m which:
Figure 1 is a perspective view of an autonomous cleaning device;
Figure 2 is a front view of the autonomous cleaning device of Figure 1,
Figure 3 is a side view of the autonomous cleaning device of Figure 1,
Figure 4 is a plan view of a room in which the autonomous cleaning device can operate, showing the use of barπers,
Figure 5 shows one form of barπer for use with the autonomous cleaning device,
Figure 6 shows the hinge mechanism of the barner of Figure 5,
Figure 7 shows a cross-sectional view along line X-X of Figure 6,
Figures 8 and 9 show two aπangements for a hinged barπer,
Figure 10 shows another type of barner for use with the autonomous cleaning device,
Figure 11 shows a cross-sectional view along line Y-Y of Figure 10,
Figure 12 shows a further type of barπer for use with the autonomous cleaning device, and,
Figure 13 is a plan view of a room showing how barπers can be used to divide the room into smaller regions to confine the autonomous cleaning device
Figure 1 shows one example of a vacuum cleaner 100 that is capable of autonomously cleaning a room The vacuum cleaner 100 has a supporting chassis 102 which is generally circular in shape and is supported on two dπven 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 which will be descπbed below The dπven 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 dπven wheel 104 is moulded from a high-strength plastics mateπal and cames a comparatively soft, πdged band around its circumference to enhance the grip of the wheel 104 when the cleaner 100 is traversing a smooth floor The soft, πdged band also enhances the ability of the wheels 104 to mount and climb over small obstacles. The driven wheels 104 are mounted independently of one another via support beaπngs (not shown) and each dπven wheel 104 is connected directly to a motor 105 which is capable of driving the respective wheel 104 in either a forward direction or a reverse direction. By driving both wheels 104 forward at the same speed, the cleaner 100 can be dπven in a forward direction. By driving both wheels 104 in a reverse direction at the same speed, the cleaner 100 can be dπven in a backward direction. By dπvmg the wheels 104 in opposite directions, the cleaner 100 can be made to rotate about its own central axis so as to effect a turning manoeuvre. The aforementioned method of dπving a vehicle is well known and will not therefore be descπbed any further here.
Mounted on the underside of the chassis 102 is a cleaner head 122. The chassis 102 carries a plurality of sensors which are designed and aπanged 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 compπse several ultra-sonic sensors and several infra-red sensors. The array of sensors will be descπbed in more detail below. Control software, composing navigation controls and steeπng devices for navigating and manoeuvring the cleaner 100 around a defined area in order to clean the carpet or other surface within the area, is housed within a housing 142 located beneath a control panel 144 or elsewhere within the cleaner 100. In the manner of known autonomous vehicles, the control software is able to receive the outputs of the sensors and to dπve the motors 105 so that obstacles are avoided whilst following a path specified by algoπthms appropπate to the nature of the vehicle. Any appropπate software can be used in this way to navigate the cleaner 100 around a room to be cleaned.
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 a suction opening in the cleaner head 122. The chassis 102 also carπes a cyclonic separator 152 for separating dirt and dust from the air drawn into the cleaner 100. The cyclonic separator, which preferably composes two cyclones in seπes, need not be described any further here, being known technology and descπbed adequately elsewhere.
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 dπven by the motois 105 which, turn, are powered by the batteπes 160. 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 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 behind the dπven wheels 104. The battery packs 160 also power the motor and fan unit 150 which draws air into the cleaner 100 via the cleaner head 122 and passes it to the cyclonic separator 152 where the dirt and dust is separated from the airflow. The battery packs 160 are also used to power the motor which drives the brush bar 125 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, as is common in many appliances, including vacuum cleaners.
The sensor aπay forming part of the vacuum cleaner 100 will now be descπbed m more detail. The aπay compπses a plurality of ultra-sonic sensors and a plurality of infra-red sensors. The majoπty 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, as can be seen from Figures 5a and 5b. However, 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 100. Details are given below.
Three ultra-sonic sensors 202, 204 and 206, each consisting of an ultra-sonic emitter and an ultra-sonic receiver, are positioned in the forward surface 180. A first of the said ultra-sonic sensors 202, comprising an emitter 202a and a receiver 202b, is directed in a forward direction so that the emitted signals are transmitted in the normal forward direction of travel of the cleaner 100. A second ultra-sonic sensor 204, composing an emitter 204a and a receiver 204b, is directed such that the emitted signals are transmitted outwardly to the left of the cleaner 100 in a direction which is perpendicular to the direction of transmission by the ultra-sonic sensor 202. A third ultra-sonic sensor 206. composing an emitter 206a and a receiver 206b, is directed such that the emitted signals are transmitted outwardly to the πght of the cleaner 100 in a direction which is perpendicular to the direction of transmission by the ultra-sonic sensor 202 and opposite to the direction of transmission by the ultra-sonic sensor 204. A fourth ultra-sonic sensor (not shown) is located in the rear of the cleaner 100 and is directed rearwardly so 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, πght and rear of the cleaner 100.
A fifth ultra-sonic sensor 210 is located in the forward surface 180. The fifth ultra-sonic sensor 210 compπses an emitter 210a and a receiver 210b The fifth ultra-sonic sensor 210 is positioned so that the emitter 210a transmits at an angle which is substantially midway between the directions in which the forward- and left-looking sensors 202, 204 transmit. In the embodiment, the sensor 210 transmits in a direction of 45° to the normal forward direction of travel of the vacuum cleaner 100 As can be seen from Figure 1, the sensor 210 transmits to the side of the cleaner 100 on which the cleaner head 122 protrudes.
The inclusion of the sensor 210 provides the vehicle 100 with greater angular control as it moves along a wall or other obstacle with the cleaner head 122 thereagainst or parallel thereto. The sensor 210 is able to detect the presence of a wall or similar large obstacle and, if the wall or other obstacle alongside which the vehicle is moving disappears (for
example, when a corner is encountered), then the vehicle 100 is made aware of the change earlier than it would have been if the sensor 210 had not been present. This allows the vehicle to take account of corners and other changes m its environment with greater accuracy and manoeuvrab ty.
A plurality of infra-red sensors are also included in the forward surface 180 The infrared sensors compπse emitters 220 and receivers 230. Most of the emitters 220 are aπanged in four groups of three which are spaced substantially evenly around the forward surface 180 Two additional emitters 226 are positioned close to the central axis of the cleaner 100 and are directioned so that they emit signals in a substantiall} forward direction with respect to the normal direction of travel
Further infra-red sensors 260, 262 are positioned on the chassis 102 immediately above the protruding end of the cleaner head 122 Each sensor 260, 262 compπses an emitter and a receiver. The first of these sensors 260 is directioned so that the emitter emits a signal in a direction parallel to the longitudinal axis of the cleaner head 122. The direction of the signal from the sensor 260 is therefore perpendicular to the forward direction of travel and parallel to the direction of the signal emitted by emitter 221 The sensor 260 is thus able to detect the distance of a wall or other obstacle along which the cleaner 100 is intended to travel In combination with the emitter 221 and the receivei 230a, the sensor 260 is also able to maintain the direction of travel of the cleaner 100 parallel with the wall or other obstacle along which the cleaner 100 is intended to travel This is achieved by way of the parallel signals being maintained essentially identical Any vaπation between the two signals can be easily recognised and the path of the cleaner 100 can then be adjusted to compensate for the discrepancy. As will be seen from the figure, the distance between the directions of the two signals is approximately one half of the length of the cleaner 100, although this can be vaπed to a considerable extent. Preferably, the distance will not be less than a quarter of the length of the vehicle nor more than three quarters thereof.
Passive infra-red detectors 240a, 240b, are located in the forward surface 180 for the purpose of detecting heat sources such as humans, animals and fires. The passive infrared detectors 240 are directioned so that they look m a forward direction to detect heat sources in the path of the cleaning device 100.
Two forward-looking ultra-sonic sensors 250, each composing an emitter 250a and a receiver 250b, are positioned at an uppermost extremity of the cleaner 100 so that they aie able to sense obstacles immediately in front of the cleaner and at or near an uppermost extremity thereof. In this case, the sensors 250 are positioned in the casing of the fan and motor unit 150 so that they both look along the uppermost edge of the cyclonic separator 152. The direction of each sensor 250 is parallel to the direction of the other sensor 250 The sensors 250 are able to detect any obstacles which are at a sufficiently high level not to be detected by the sensors aπanged in the forward surface 180 but which would constitute an obstruction to the forward movement of the cleaner 100. Rearward-looking sensors could also be provided at a high level if required, but none is shown in the embodiment illustrated in the drawings. It will be appreciated that a similar effect can be achieved using sensors (preferably ultra-sonic sensors) positioned lower on the cleaner than the uppermost extremity but directioned so as to look towards the appropriate area adjacent the uppermost extremity m front of the cleaner 100
Figure 4 shows a room 420 in which the cleaner can be used. Room 420 has an open fireplace 401, a descending stairway 402 and a plant 403 with branches that trail onto or near to the floor of the room. These features may present a problem for an autonomous cleaner as the cleaner may not be able to recognise these obstacles or be able to avoid them using its aπay of on-board sensors. The fireplace 401 will usually be successfully detected by pyroelectπc or passive mfra-red (PIR) sensors on the cleaner, but hot ashes may damage the cleaner if it strays too close to the fire. The stairway 402 may not be successfully recognised by some types of cleaner, which could lead to the cleaner becoming stuck at the top of the stairs 402 or falling down the stairs. The trailing branches of plant 403 may not present a distinct boundary that the cleaner can
recognise, which could cause the cleaner to become stuck due to the branches becoming wound around the cleaner brushbar or wheels.
The dashed lines 405, 406, 407 represent the positioning of barπers which a user sets up in the room. The user positions these barπers around the obstacles that the cleaner is likely to have a problem in avoiding The cleaner can detect the presence of these bamers using its on-board sensors and, in traversing the floor area, will travel around the barner thus safely avoiding the obstacle 401, 402, 403 hidden behind the barπer
It will be appreciated that other room features or obstacles can be guarded using the barner in the same manner as descπbed above
Various forms of barner will now be descπbed with reference to Figures 5 to 12.
Figure 5 shows a barπer 500 comprising a plurality of planar stπps 501. 502, 503 that are hinged 504, 505 together. The hinges 504, 505 allow the stπps to be rotated through 360° with respect to one another. This allows the stπps 501, 502, 503 to be positioned in various configurations, as required by the obstacle that is being guarded, and it also allows the strips to be folded in a concertina fashion so as to he against one another for compact storage. As shown in Figure 6, the barπer is hinged by forming ends of the planar stπps 501, 502 with a pair of hook-like portions 510, 511 which can hook onto a tubing piece 504 Figure 7 shows the cross-section along line X-X m Figure 6 It will be appreciated that there are many other possibilities for hinging the stπps togethei Each end of a stπp 501 may have a plurality of spaced apart holes and connecting πngs can be passed through holes in adjacent stπps. Alternatively, adjacent ends of stπps 501, 502 may be joined by a length of tape to form a flexible hinge or the hinge may be a weakening line the stπp itself.
The height of each stπp 501, 502 is chosen so as to be sufficient to reflect the inteπogatory radiation, such as ultrasound or mfra-red radiation, received from the sensors on the cleaning device 100. As shown in Figure 2, cleaning device 100 has a
belt of sensors around its peπphery, and the barπer 500 extends at least as high as the sensors Typically the barπer has a height of around 70mm The surface of barner 500 is supported so that it extends generally vertically with respect to the floor, and the mateπal from which the barrier 500 is formed should be one that is reasonably good at reflecting radiation of the type used by the sensois on the cleaning device 100 Polypi opylene and other plastics or metals are particularly suitable materials These materials also have the advantage that the barπer 500 is strong enough to withstand repeated use and a user accidentally treading on or kicking the barπer The planar stπps 501, 502, 503 present a smooth surface that the cleaning device can easily follow The joins 504, 505 between each pair of stπps also present a smooth transition that the cleaning device can follow
The total length of the barπer 500 is chosen so as to be sufficient to span most obstacles usually encountered in a room, typically lm Of course, several barπers 500 can be used together where it is necessary to span a wide obstacle The length of each individual stπp 501 is chosen so that the length of the barner, when collapsed, is short enough to be easily stored Figures 8 and 9 show two prefeπed aπangements for the stπps forming the barner In Figure 8, the stπps 501, 502, 503, 504 are alternately of long and short lengths Thus strip 501 is longer than stπp 502, and strip 503 is longer than stπp 502 This allows the hinges, which are relatively bulky pieces, to concertina into a flatter form than would be possible if the stπps were all of equal length, since in Figure 8 hmges do not stack against one another in the folded state The same advantage is achieved by the aπangement shown in Figure 9, where the stπps 515, 516, 517, 518, 519 are of progressively decreasing length
The aπangement of hinged parts is self-supporting in most configurations However, where additional support is required, such as when the stπps 501, 502, 503 are all aligned with one another, it is possible to use additional support means The support means can compπse parts which he on the floor surface and have a groove to accept the stπp 501 and support it in a vertical position
Figure 10 shows another form of barner A length of flexible mateπal 601 such as strong paper, plastic sheeting or fabπc, is wound inside a housing 602. A free end of the stπp 601 is secured to a support 604 that is capable of standing, unaided, on a floor. Support 604 is arc-shaped to fit snugly against the side of the cylindrical housing 602 when the strip is completely withdrawn inside the housing. Alternatively, the side of housing 602 may be recessed to accommodate the support 604. A knob 603 on housing 602 allows a user to rewind an extended length of the strip 601 Figure 11 shows a cross-section along line Y-Y of Figure 10 Alternatively, the stπp 601 may be resiliency biased into a wound state inside the housing 602, and withdrawn from the housing and held in the withdrawn state, similar to a cable rewind for a vacuum cleaner To use this type of barπer, a user grasps support 604 and withdraws a sufficient length of the stπp 601 from the housing 602. Both the housing 602 and the support 604 stand on the floor and the stπp 601 presents a smooth continuous surface that can reflect radiation from a cleaner's sensor array
Figure 12 shows a further form of banner. A plurality of parts 610, 611, 612 telescope together so as to present a continuous surface to the cleaning device 100. The parts 610, 611, 612 can be shdingly moved apart from one another to extend to a required length for guarding an obstacle or shded over one another to telescope together for storage. Two, three or more parts can be used as necessary. The parts have a generally 'Y'- shaped cross-section, the arms 615 providing a stable support while the vertically extending surface 614 provides a good surface for reflecting inteπogatory radiation from cleaner 100.
While the barπer is particularly useful in guarding obstacles that the cleaner may not be able to avoid itself, Figure 13 shows another use for the barπer in dividing a large area A barπer 421 is placed across a large room 420, the barner 421 extending between opposing walls of the room. This divides the room 420 into two smaller regions 422, 423 The cleaner can then be set to clean one of the regions 422. If needed, the cleaner can then be set to clean the other region 423. The barπer may alternatively be used across the threshold dividing two rooms. There may be vaπous reasons for doing this
There may be a need to operate the cleaner in a room that is being used by humans or animals By placing the baπier across the room 421, a human or animal can continue to use region 423 while the cleaner operates unhindered m region 422. A particular region of the room may require cleaning more regularly than the entire room, such as a region of the room that is subject to high traffic, where an animal is kept, or a dining area The baπier 421 can be placed across the room so that the cleaner is confined to the region that requires the regular cleaning Also, it may be known that the cleaner has insufficient battery power to traverse the entire room, so the room is divided into regions 422. 423, with the cleaner being able to completely traverse one of the regions without stopping to have its battenes recharged