Title:
Automatic traveling cleaner for automatically cleaning surface to be cleaned by discriminating object placed on surface to be cleaned
Kind Code:
A1


Abstract:
It is determined whether a sensor band reacts and, if the sensor band reacts, it is determined whether the sensor band continues to react for a predetermined period of time. If the sensor band continues to react for the predetermined period of time in the previous step, it is determined that sucking is dangerous because an object is considered as an object that may possibly obstruct a cleaning work, for example, a long object such as a cord-shaped object. In accordance therewith, a control unit gives a command for stoppage of the sucking of a suction unit, whereby decrease of the sucking power by entanglement with a long object such as a cord-shaped object can be prevented, and the cleaning work can be carried out efficiently and safely.



Inventors:
Uehigashi, Naoya (Osaka, JP)
Application Number:
11/038966
Publication Date:
08/04/2005
Filing Date:
01/20/2005
Assignee:
Funai Electric Co., Ltd. (Osaka, JP)
Primary Class:
International Classes:
A47L9/28; A47L5/00; (IPC1-7): A47L5/00
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Primary Examiner:
TILL, TERRENCE R
Attorney, Agent or Firm:
OSHA BERGMAN WATANABE & BURTON LLP (HOUSTON, TX, US)
Claims:
1. An automatic traveling cleaner that performs cleaning via a cleaning suction port disposed on a bottom surface and having a predetermined area, comprising: a suction unit which performs suction via said cleaning suction port; a sensor unit which is disposed on said bottom surface, is placed ahead of said cleaning suction port in a movement direction, and detects an object on a surface to be cleaned; and a control unit which controls suction operation of said suction unit in accordance with a detection result from said sensor unit, wherein said sensor unit includes: a determination region which is disposed ahead of said cleaning suction port in the movement direction and has an area larger than said predetermined area; a first sensor band which can detect said object in a region having a dimension larger than a maximum dimension of said cleaning suction port along a direction orthogonal to the movement direction; and a second sensor band which can detect said object in a region having a dimension larger than a maximum dimension of said cleaning suction port along the movement direction, said first sensor band is disposed ahead of said determination region in the movement direction and near to an outer circumference of said determination region in the direction orthogonal to the movement direction, said second sensor band is disposed near to the outer circumference of said determination region along the movement direction, each of said first sensor band and said second sensor band has a plurality of sensors that detect said object for each predetermined region thereof, and said control unit gives a command for stoppage of suction of said suction unit in accordance with the number of sensors that have reacted among said plurality of sensors of at least one of said first sensor band and said second sensor band when said object continues to be detected for the predetermined period of time by at least one of said first sensor band and said second sensor band, said automatic traveling cleaner further comprising: a roller which is disposed on said cleaning suction port; and a roller drive unit which controls rotation of said roller, wherein said control unit gives a command for stoppage of rotation of said roller to said roller drive unit when said object continues to be detected for the predetermined period of time by at least one of said first sensor band and said second sensor band, said second sensor band has a first subsensor band and a second subsensor band that are disposed along the movement direction are disposed respectively on a left side and a right side of said determination region, and can detect said object in the region having the dimension larger than the maximum dimension of said cleaning suction port along the movement direction, and one of said first subsensor band and said second subsensor band operates in accordance with said movement direction.

2. An automatic traveling cleaner that performs cleaning via a cleaning suction port disposed on a bottom surface and having a predetermined area, comprising: a suction unit which performs suction via said cleaning suction port; a sensor unit which is disposed on said bottom surface, is placed ahead of said cleaning suction port in a movement direction, and detects an object on a surface to be cleaned; and a control unit which controls suction operation of said suction unit in accordance with a detection result from said sensor unit.

3. The automatic traveling cleaner according to claim 2, wherein said sensor unit includes: a determination region which is disposed ahead of said cleaning suction port in the movement direction and has an area larger than said predetermined area; a first sensor band which can detect said object in a region having a dimension larger than a maximum dimension of said cleaning suction port along a direction orthogonal to the movement direction; and a second sensor band which can detect said object in a region having a dimension larger than a maximum dimension of said cleaning suction port along the movement direction, said first sensor band is disposed ahead of said determination region in the movement direction and near to an outer circumference of said determination region in the direction orthogonal to the movement direction, and said second sensor band is disposed near to the outer circumference of said determination region along the movement direction.

4. The automatic traveling cleaner according to claim 3, wherein said control unit gives a command for stoppage of suction of said suction unit when said object continues to be detected for a predetermined period of time by at least one of said first sensor band and said second sensor band.

5. The automatic traveling cleaner according to claim 4, further comprising: a roller which is disposed on said cleaning suction port; and a roller drive unit which controls rotation of said roller, wherein said control unit gives a command for stoppage of rotation of said roller to said roller drive unit when said object continues to be detected for a predetermined period of time by at least one of said first sensor band and said second sensor band.

6. The automatic traveling cleaner according to claim 3, wherein each of said first sensor band and said second sensor band has a plurality of sensors that detect said object for each predetermined region thereof, and said control unit gives a command for stoppage of suction of said suction unit in accordance with the number of sensors that have reacted among said plurality of sensors of at least one of said first sensor band and said second sensor band when said object continues to be detected for a predetermined period of time by at least one of said first sensor band and said second sensor band.

7. The automatic traveling cleaner according to claim 6, further comprising: a roller which is disposed on said cleaning suction port; and a roller drive unit which controls rotation of said roller, wherein said control unit gives a command for stoppage of rotation of said roller to said roller drive unit when said object continues to be detected for a predetermined period of time by at least one of said first sensor band and said second sensor band.

8. The automatic traveling cleaner according to claim 3, wherein said second sensor band has a first subsensor band and a second subsensor band that are disposed along the movement direction, are disposed respectively on a left side and a right side of said determination region, and can sense a dimension larger than the maximum dimension of said cleaning suction port along the movement direction, and one of said first subsensor band and said second subsensor band operates in accordance with said movement direction.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic traveling cleaner having an auto-traveling function in a main body of the cleaner and automatically performing cleaning of a surface to be cleaned.

2. Description of the Background Art

Conventionally, a cleaner has been developed in which a movement function is added to the cleaner so as to aim improvement of operability during the cleaning. Particularly, in recent years, development of an automatic traveling cleaner of a so-called self-inducing type obtained by mounting a microcomputer or the like and various sensors thereon is attracting people's attention. An automatic traveling cleaner of this type (hereinafter, simply referred to also as cleaner), when started to operate, begins to travel along a straight line by means of wheels driven by a driving motor. During the traveling, the cleaner measures the distance to obstacles such as furniture with a plurality of sensors or the like, confirms the step difference of the surface to be cleaned so as to travel by side stepping the step difference, and sucks the dust adhering to the surface to be cleaned by using a suction port and a brush or the like disposed in the bottom part of the main body, thereby automatically performing cleaning of the surface to be cleaned.

Japanese Patent Laying-Open No. 06-113984 discloses an automatic traveling cleaner that executes automatic cleaning by being made to learn the information necessary for cleaning in advance, and continues cleaning while evading the obstacles by sensing the distance to the obstacles with the use of a sensor.

However, in a conventional automatic traveling cleaner, it was not possible to discriminate the objects placed on the surface to be cleaned, so that all the objects placed on the surface to be cleaned were sucked.

Therefore, when an elongate entangling object such as a cord is placed, such an object may be erroneously sucked through the suction port by the cleaner while traveling and is entangled to reduce the suction power through the suction port, thereby raising a possibility of obstructing the cleaning work.

SUMMARY OF THE INVENTION

The present invention has been made in order to solve the aforementioned problems and, therefore, aims to provide an automatic traveling cleaner that avoids suction of an object that may possibly obstruct a cleaning work by discriminating the object placed on a surface to be cleaned.

According to the present invention, an automatic traveling cleaner that performs cleaning via a cleaning suction port disposed on a bottom surface and having a predetermined area includes a suction unit which performs suction via the cleaning suction port, a sensor unit which is disposed on the bottom surface, is placed ahead of the cleaning suction port in a movement direction, and detects an object on a surface to be cleaned, and a control unit which controls suction operation of the suction unit in accordance with a detection result from the sensor unit. The sensor unit includes a determination region which is disposed ahead of the cleaning suction port in the movement direction and has an area larger than the predetermined area, a first sensor band which can detect the object in a region having a dimension larger than a maximum dimension of the cleaning suction port along a direction orthogonal to a movement direction, and a second sensor band which can detect the object in a region having a dimension larger than a maximum dimension of the cleaning suction port along the movement direction. The first sensor band is disposed ahead of the determination region in the movement direction and near to an outer circumference of the determination region in the direction orthogonal to the movement direction. The second sensor band is disposed near to an outer circumference of the determination region in the movement direction. Each of the first sensor band and the second sensor band has a plurality of sensors that detect the object for each predetermined region thereof. The control unit gives a command for stoppage of suction of the suction unit in accordance with the number of sensors that have reacted among the plurality of sensors of at least one of the first sensor band and the second sensor band when the object continues to be detected for a predetermined period of time by at least one of the first sensor band and the second sensor band. The automatic traveling cleaner further includes a roller which is disposed on the cleaning suction port, and a roller drive unit which controls rotation of the roller. The control unit gives a command for stoppage of rotation of the roller to the roller drive unit when the object continues to be detected for a predetermined period of time by at least one of the first sensor band and the second sensor band. The second sensor band has a first subsensor band and a second subsensor band that are disposed along the movement direction are disposed respectively on a left side and a right side of the determination region, and can detect the object in the region having the dimension larger than the maximum dimension of the cleaning suction port along the movement direction. One of the first subsensor band and the second subsensor band operates in accordance with the movement direction.

According to the present invention an automatic traveling cleaner that performs cleaning via a cleaning suction port disposed on a bottom surface and having a predetermined area includes a suction unit which performs suction via the cleaning suction port, a sensor unit which is disposed on the bottom surface, is placed ahead of the cleaning suction port in a movement direction, and detects an object on a surface to be cleaned, and a control unit which controls suction operation of the suction unit in accordance with a detection result from the sensor unit.

Preferably, the sensor unit includes a determination region which is disposed ahead of the cleaning suction port in the movement direction and has an area larger than the predetermined area, a first sensor band which can detect the object in a region having a dimension larger than a maximum dimension of the cleaning suction port along a direction orthogonal to the movement direction, and a second sensor band which can detect the object in a region having a dimension larger than a maximum dimension of the cleaning suction port along the movement direction. The first sensor band is disposed ahead of the determination region in the movement direction and near to an outer circumference of the determination region in a direction orthogonal to the movement direction. The second sensor band is disposed near to an outer circumference of the determination region in the movement direction.

In particular, the control unit gives a command for stoppage of suction of the suction unit when the object continues to be detected for a predetermined period of time by at least one of the first sensor band and the second sensor band.

In particular, each of the first sensor band and the second sensor band has a plurality of sensors that detect the object for each predetermined region thereof. The control unit gives a command for stoppage of suction of the suction unit in accordance with the number of sensors that have reacted among the plurality of sensors of at least one of the first sensor band and the second sensor band when the object continues to be detected for a predetermined period of time by at least one of the first sensor band and the second sensor band.

In particular, the automatic traveling cleaner according to the present invention further includes a roller which is disposed on the cleaning suction port, and a roller drive unit which controls rotation of the roller. Herein, the control unit gives a command for stoppage of rotation of the roller to the roller drive unit when the object continues to be detected for a predetermined period of time by at least one of the first sensor band and the second sensor band.

In particular, the second sensor band has a first subsensor band and a second subsensor band that are disposed in the movement direction are disposed respectively on a left side and a right side of the determination region, and can sense a dimension larger than the maximum dimension of the cleaning suction port along the movement direction. One of the first subsensor band and the second subsensor band operates in accordance with the movement direction.

The automatic traveling cleaner according to the present invention gives a command for stoppage of suction of the suction unit when the object continues to be detected for a predetermined period of time by at least one of the first sensor band and the second sensor band. In other words, the cleaner stops suction of the suction unit by discriminating an elongate object such as a cord which is an object that continues to be detected for the predetermined period of time. This can evade decrease or the like in the suction power of the suction unit that is generated by entanglement, and the cleaning work can be carried out efficiently and safely.

The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a bottom part of a cleaner according to an embodiment of the present invention;

FIG. 2 is a schematic block diagram describing the mechanism of the cleaner according to the embodiment of the present invention;

FIG. 3 is a conceptual view describing the cleaner according to the embodiment of the present invention that travels in a room as one example;

FIG. 4 is a flowchart describing a method of discriminating objects during the cleaning work in a control unit according to the embodiment of the present invention;

FIGS. 5A to 5C are conceptual views describing the method of discriminating objects that has been described in the flowchart of FIG. 4; and

FIG. 6 is a flowchart describing a method of discriminating objects in an automatic traveling cleaner according to a modification of the embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail with reference to the attached drawings. Here, in the drawings, identical or corresponding parts will be denoted with the same reference numerals and the description thereof will not be repeated.

Referring to FIG. 1, a cleaner 20 according to an embodiment of the present invention includes a wheel 22 disposed on the front side relative to the movement direction as a movement function, a left wheel 23 and a right wheel 24 disposed on the rear side, a suction port 21 for sucking dust and the like on a surface to be cleaned, sensor bands 26 to 28 that detect objects placed on the surface to be cleaned, and a brush 29 that is disposed in suction port 21 and rotates in contact with the surface to be cleaned so as to brush the dust and the like into the suction port.

Left wheel 23 and right wheel 24 are each driven independently, and wheel 22 controls the direction driving. In the forward movement, left wheel 23 and right wheel 24 operate to proceed the cleaner in the forward direction. In turning the direction, wheel 22 rotates so as to achieve a desired movement direction while left wheel 23 and right wheel 24 operate to turn the direction.

Each of sensor bands 26 to 28 has a plurality of sensors sn. In FIG. 1, as one example, sensor bands 26 and 27 are each provided with five sensors sn arranged and spaced apart by a predetermined interval. The number of sensors in sensor bands 26 and 27 is set so that a range having a dimension larger than the maximum dimension of suction port 21 in the movement direction can be sensed. Further, sensor band 28 is provided with 20 sensors sn arranged and spaced apart by a predetermined interval. The number of sensors in sensor band 28 is set so that a range having a dimension larger than the maximum dimension of suction port 21 in a direction perpendicular to the movement direction can be sensed.

In the bottom surface part, a sensing region 25 having an area larger than the area of the suction port is disposed ahead of suction port 21 in the movement direction. Sensor bands 26 to 28 are disposed so as to surround this sensing region 25. Specifically, sensor bands 26 and 27 are disposed respectively on the left side and on the right side near to the outer circumference of sensing region 25 along the movement direction. Sensor band 28 is disposed near to the outer circumference of sensing region 25 along the direction perpendicular to the movement direction. Sensor band 28 is disposed ahead of sensing region 25 in the movement direction.

Referring to FIG. 2, cleaner 20 according to an embodiment of the present invention includes a control unit 2 that controls the cleaner as a whole, a position/speed detection unit 3 for sensing the position and the speed of the cleaner and outputting a sensing result to control unit 2, a motor unit 4 for rotating wheels 22 to 24, a driving control unit 5 that controls the rotation and direction of the wheels in motor unit 4 by receiving a command from control unit 2, a brush motor 6 for rotating brush 29 disposed in suction port 21, a brush control unit 7 that controls rotation of brush motor 6 by receiving a command from control unit 2, a suction unit 8 for collecting dusts by a sucking force in suction port 21 by receiving a command from control unit 2, and a suction sensor unit 9 disposed on the bottom surface part wherein sensor bands 26 to 28 directed towards the surface to be cleaned react to output a sensing result to control unit 2.

Here, the traveling of the cleaner will be described.

With reference to FIG. 3, cleaner 20 according to an embodiment of the present invention that travels inside a room 30 will be described as one example. Cleaner 20 is placed at an end in the inside of room 30, and the cleaning is started. Here, information necessary for cleaning, specifically, necessary information such as the region of cleaning, start position of cleaning, path of cleaning, and end position of cleaning, is stored in advance in a storage unit (not illustrated), and the cleaner carries out the cleaning work in accordance with the contents stored in the storage unit.

Specifically, the cleaning work is started, for example, at an end of the inside of room 30, and cleaner 20 proceeds forward at a constant speed. At that time, control unit 2 gives a command so that cleaner 20 may travel along a desired path of cleaning in accordance with the sensing result on the position and the speed obtained in position/speed detection unit 3. Further, when a forward wall of the room is sensed by a forward sense unit (not illustrated) that senses the front, the cleaner turns the direction, and proceeds at a constant speed again by being shifted by a predetermined position. When cleaner 20 is started at the cleaning start position of the cleaning region, driving control unit 5 is driven by control of control unit 2 along the cleaning path in the contents stored in the storage unit, whereby the cleaning can be performed automatically up to the cleaning end position.

Here, with reference to the flowchart of FIG. 4, a method of discriminating an object during the cleaning work by control unit 2 according to an embodiment of the present invention will be described.

With reference to FIG. 4, first, the cleaning work of cleaner 20 is started (step S0). Next, during the traveling, it is determined whether the sensor bands react (step S1). Specifically, it is determined whether at least one of the sensors sn in the sensor bands reacts. In the method of discriminating an object according to this embodiment, sensor band 28 and one of sensor band 26 and sensor band 27 are used. As one example, in the case shown in FIG. 3, in the first cleaning path L1, sensor band 27 and sensor band 28 are used. After the direction is turned, in the cleaning path L2, sensor band 26 and sensor band 28 are used. Namely, control unit 2 gives a command on the sensor bands to be used to suction sensor unit 2 in turning the direction in accordance with the cleaning path stored in advance in the storage unit.

When the sensor bands do not react in step S1, the flow stays in step S1 until the sensors react. On the other hand, when the sensor bands react in step S1, the flow proceeds to the next step S2.

In step S2, it is determined whether the sensor bands continue to react for a predetermined period of time. When the reaction of the sensor bands ends within the predetermined period of time in step S2, it is determined that the suction is possible (step S2#a), and the flow returns to the first step S1. This predetermined period of time is set within the period of time from the time when the sensor band 28 in FIG. 1 begins to react to an object until the object reaches suction port 21. Specifically, the predetermined period of time is set in accordance with the speed of the cleaner and the distance from suction port 21 to sensor band 28.

On the other hand, when the sensor bands continue to react for the predetermined period of time in step S2, it is determined that the suction is dangerous (step S2#). In accordance therewith, in the next step S3, control unit 2 gives a command for stoppage of the suction of suction unit 8 (step S3).

Next, in step S4, the flow stays until the reaction of the sensor bands ends. When the reaction of the sensor bands ends, the flow proceeds to the next step, and control unit 2 gives a command for operation of the suction of suction unit 8 after a fixed period of time passes (step S5). This restarts the cleaning work, and in the next step S6, it is determined whether the cleaning work is finished. When the cleaning work is finished in step S6, the operation of the cleaner is ended (step S7). If the cleaning work is not finished yet in step S6, the flow returns to the first step S1.

Here, this fixed period of time is a period of time until the object that has been regarded as being dangerous on the surface to be cleaned passes by, and is set in accordance with the speed of the cleaner.

Here, although not illustrated, together with the commands for stoppage of the suction of suction unit 8 and operation of the suction of suction unit 8, control unit 2 gives commands for stoppage of the rotation and restart of the rotation of brush 29 to brush control unit 7.

Therefore, the suction through suction port 21 or suction by rotation operation of brush 29 in accordance with the rotation of brush motor 6 is stopped, thereby preventing suction of an object that is regarded as being dangerous when being sucked.

With reference to FIG. 5A, in this example, an elongate cord-shaped object 50 is shown.

In this example, as described in FIG. 4, cleaner 20 in accordance with an embodiment of the present invention senses with sensor bands 27 and 28 in step S1, and proceeds to the next step S2. In the next step S2, since the sensor bands 27 and 28 continue to react for a predetermined period of time, the flow proceeds to the next step S2#. Namely, the sucking is determined as being dangerous, and control unit 2 gives a command for stoppage of the suction of suction unit 8. This can evade the danger of sucking such an elongate cord-shaped object 50 through suction port 21. Then, in the next step S4, the cleaning work is started when a fixed period of time passes after the reaction of sensor bands 27 and 28 ends. Therefore, stoppage of the cleaning function by entanglement of object 50 is evaded, so that the cleaning work can be stably carried out.

With reference to FIG. 5B, in this example, a suckable object 51 is shown instead of the elongate chord-shaped object 50 shown in FIG. 5A.

In this example, as described in FIG. 4, the cleaner senses with sensor bands 27 and 28 in step S1, and proceeds to the next step S2. In the next step S2, since this object is not an elongate object, the sensor bands 27 and 28 stop reacting when the object completely enters the sensor region 25. Namely, since the sensor bands 27 and 28 do not continue to react for the predetermined period of time, it is determined that the sucking is possible, and the flow returns to the first step S1. By this, control unit 2 does not give a command for stoppage of the suction of suction unit 8, whereby the normal cleaning work is continued, and object 51 is sucked through suction port 21 by suction unit 8.

With reference to FIG. 5C, in this example, an object 52 that may possibly be sucked is shown at an end of suction port 21.

In this example, as described in FIG. 4, the cleaner senses with sensor bands 27 and 28 in step S1, and proceeds to the next step S2. In the next step S2, since the sensor bands 27 and 28 continue to react for a predetermined period of time, the flow proceeds to the next step S2#. Namely, the sucking is determined as being dangerous, and control unit 2 gives a command for stoppage of the suction of suction unit 8, in the same manner as in FIG. 5A.

In this case, depending on the sucking power, the object 52 may be sucked through the lateral side. Therefore, supposing that object 52 is an elongate cord-shaped object such as object 50, the sucking of suction unit 8 is stopped, whereby the danger of sucking the object through suction port 21 can be evaded with certainty.

On the other hand, supposing that object 52 is not an elongate cord-shaped object such as object 50 and is simply normal rubbish, the object can be sucked through suction port 21 in the next cleaning path after the direction is turned. For example, the determination such as in FIG. 5C is made in the cleaning path L1 of FIG. 3, and the process is carried out in accordance with a determination method similar to the one described above in the next cleaning path L2. Namely, when object 52 is an elongate cord-shaped object such as object 50, control unit 2 gives a command for stoppage of the suction of suction unit 8, whereas when object 52 is normal rubbish, object 52 is sucked through suction port 21 by suction unit 8.

Here, as described above, in the above-mentioned determination method, sensor bands 27 and 28 are used in the cleaning path L1, and sensor bands 26 and 28 are used in the cleaning path L2.

By an automatic traveling cleaner according to the embodiment of the present invention, the danger of entangling an elongate cord-shaped object in the suction port can be evaded with certainty, so that the cleaning work can be carried out efficiently and safely by differentiating normal rubbish from others.

Modification of the Embodiment

In the above-described embodiment, a determination method of differentiating an elongate cord-shaped object to perform the cleaning work safely has been described. On the other hand, when the object is large compared with suction port 21, there is little danger of sucking the object through suction port 21.

As a modification of the embodiment, a determination method of differentiating a large object that has no possibility of being sucked will be described.

With reference to the flowchart of FIG. 6, a method of differentiating an object in an automatic traveling cleaner according to a modification of the embodiment of the present invention will be described.

With reference to FIG. 6, as described in the above-mentioned embodiment, the cleaning work of cleaner 20 is started (start) (step S0). Next, it is determined whether the sensor bands react during the traveling (step S1). When the sensor bands do not react in step S1, the flow stays in step S1 until the sensor bands react. On the other hand, when the sensor bands react in step S1, the flow proceeds to the next step S2. In step S2, it is determined whether the sensor bands continue to react for a predetermined period of time. When the reaction of the sensor bands ends within the predetermined period of time, it is determined that sucking is possible (step S2#a), and the flow returns to the first step S1. On the other hand, when the sensor bands continue to react for the predetermined period of time in step S2, the flow proceeds to the next step S2a.

In step S2a, it is determined whether a predetermined number or more of the sensors are reacting. When the predetermined number or more of the sensors are reacting in step S2a, it is determined that the suction of the object through suction port 21 is impossible (step S2b), and the cleaning work is continued (step S2c). Then, the flow proceeds to step S6.

When the predetermined number or more of the sensors do not react, the flow proceeds to step S2#, where it is determined that the suction is dangerous. The subsequent processing procedures are the same as described with reference to the flowchart of FIG. 4.

In the modification of the embodiment of the present invention, the cleaning work is continued when a predetermined number or more of the sensors are reacting. In other words, the object is considered to be a large object because the predetermined number or more of the sensors are reacting. Therefore, in this case, suction of the object is considered to be impossible because the object is too large compared with the size of suction port 21. By this, it is not necessary to stop the suction by suction unit 8, so that the cleaning work can be carried out more efficiently. Here, the predetermined number of the sensors can be set in accordance with the size, shape, or the like of suction port 21, or the suction power of suction unit 8.

This allows determination of whether the suction through suction port 21 is possible or impossible, thereby achieving an efficient cleaning work.

Here, in the above-described embodiment, a method of discriminating an object has been described in which a rectangular sensing area 25 having a larger area than the area of suction port 21 in the movement direction of suction port 21 is provided, and the object is discriminated by using the flowcharts described in FIGS. 4 and 6; however, the present invention is not limited to this alone. By further enlarging the sensing area 25, a more precise process of discriminating an object can be executed, whereby an efficient cleaning work can be carried out.

Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.





 
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