Patent Description:
A robot cleaner (also called a cleaning robot) is an apparatus that automatically cleans a traveling region by suctioning foreign substances, such as dust, etc., from a floor while autonomously traveling about the travelling region without user manipulation.

After a battery of the robot cleaner is charged at a docking station, the robot cleaner performs cleaning while wirelessly traveling in the cleaning region, such that the robot cleaner has a weak suction force lower than that of a general cleaner. Recently, although various robot cleaners with increased maximum suction force have been developed and rapidly come into widespread use, battery consumption gradually increases in proportion to suction force, such that it is necessary to properly control suction force of the robot cleaner so as to increase an operation time of the robot cleaner.

<CIT> discloses an electric vacuum cleaner configured to control the input to an electric blower in accordance with the conditions of floor surfaces.

<CIT> discloses a vacuum cleaner configured to control the input to a fan motor and a nozzle motor driving a brush based on the kind of surface being cleaned.

<CIT> discloses a vacuum cleaner configured to measure the push-out and pull-back resistance experienced by a user and adjust it to a suitable level.

An object of the present disclosure is to provide a robot cleaner and a method for controlling the same, which may perform efficient cleaning by controlling a suction force or traveling route of the robot cleaner.

Another object of the present disclosure is to provide a robot cleaner and a method for controlling the same, which may recognize a floor state by detecting load applied to wheels of the robot cleaner so as to increase reliability and accuracy in floor state decision.

A still another object of the present disclosure is to provide a robot cleaner and a method for controlling the same, which may recognize a floor state by combining load applied to wheels of the robot cleaner, load applied to brushes, and acceleration information of the robot cleaner with one another in a complementary manner, thereby increasing accuracy in floor state decision.

In accordance with an aspect of the present invention, there is provided a robot cleaner according to claim <NUM> and a method for controlling a robot cleaner according to claim <NUM>.

As is apparent from the above description, the robot cleaner and the method for controlling the same according to the embodiments of the present disclosure may perform efficient cleaning by controlling a suction force or traveling route of the robot cleaner according to a floor state.

The robot cleaner and the method for controlling the same according to the embodiments of the present disclosure may detect load caught in wheels of the robot cleaner so as to increase reliability and accuracy in floor state decision, thereby recognizing a floor state.

The robot cleaner and the method for controlling the same according to the embodiments of the present disclosure may recognize a floor state by combining load caught in wheels of the robot cleaner, load caught in brushes, and acceleration information of the robot cleaner with one another in a complementary manner, thereby increasing accuracy in floor state decision.

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. A robot cleaner and a method for controlling the same according to embodiments of the present disclosure will hereinafter be described with reference to the attached drawings.

<FIG> is a control block diagram illustrating a robot cleaner according to an embodiment of the present disclosure. <FIG> is a view illustrating the external appearance of a robot cleaner according to an embodiment of the present disclosure.

Referring to <FIG> and <FIG>, a robot cleaner <NUM> according to the embodiment may include a sensing portion <NUM> configured to acquire information to be used for recognizing a floor state on which the robot cleaner <NUM> travels, a traveling portion <NUM> configured to move a main body <NUM>, a cleaning portion <NUM> configured to perform cleaning by scattering dust accumulated on the floor and suctioning the scattered dust during traveling of the robot cleaner <NUM>, a storage portion <NUM> configured to store information regarding the traveling route of the robot cleaner <NUM>, a user interface <NUM> configured to receive a control command from the user and display state information of the robot cleaner <NUM>, and a controller no configured to control the traveling portion <NUM> and the cleaning portion <NUM> on the basis of the detection result of the sensing portion <NUM> or the control command applied to the user interface <NUM>.

The traveling portion <NUM> may include traveling wheels 122a and 122b respectively mounted to left and right sides of the main body <NUM>. The controller <NUM> may move the main body <NUM> by rotation of the traveling wheels 122a and 122b, and may control the cleaning portion <NUM> during movement of the main body <NUM>, thereby cleaning the floor.

In the following embodiment to be described later, movement of the main body <NUM> may refer to traveling of the robot cleaner <NUM>, and the operation for allowing the robot cleaner <NUM> to travel and clean the floor will hereinafter be referred to as a cleaning traveling operation.

The controller <NUM> may recognize the floor state on the basis of the detection result of the sensing portion <NUM>, and may control the suction force and traveling route of the cleaning portion <NUM> on the basis of the recognized floor state.

The floor states to be recognized by the controller <NUM> may include a hard floor and a soft floor. The hard floor may refer to a smooth and hard floor such as a wooden floor, a tiled floor, a vinyl floor, etc. The soft floor may refer to a floor, such a carpet, having high resistance due to wool (or other fabric) and thus the robot cleaner <NUM> cannot easily move forward or backward. The carpet is a one-faced or double-faced three-dimensional textile product woven with pile yarns. The carpet is classified into a cut pile carpet and a loop pile carpet. The cut pile carpet is formed by cutting all of the looped fibers at the top of bundles, thereby creating an upright pile. The loop pile carpet is woven with loops of threads at its surface. If the floor state is a soft floor, the detection result of the controller <NUM> may be changed according to carpet types.

If a carpet is located on the floor, the floor covered with the carpet has higher resistance than the other floor having no carpet because the floor covered with the carpet has much dust or foreign substances inserted between carpet yarns, such that a higher suction force is needed for the robot cleaner to move on the carpet. Accordingly, the controller <NUM> may increase the suction force of the cleaning portion <NUM> when the floor state is the soft floor as compared to the other case in which the floor state is the hard floor, thereby increasing cleaning efficiency. In contrast, the controller <NUM> may relatively reduce the suction force of the cleaning portion <NUM> when the floor state is the hard floor, such that unnecessary power consumption is reduced and an available cleaning time of the robot cleaner <NUM> is elongated.

<FIG> is a detailed control block diagram illustrating the robot cleaner according to an embodiment of the present disclosure. <FIG> is a view illustrating an internal structure of the robot cleaner according to an embodiment of the present disclosure. <FIG> is a bottom view illustrating the robot cleaner according to an embodiment of the present disclosure.

Referring to <FIG>, the traveling portion <NUM> may include a traveling wheel <NUM> (composed of wheels 122a and 122b) respectively located at left and right ends of the main body <NUM>, a caster wheel <NUM> provided at the bottom surface of the main body <NUM>, and a wheel motor <NUM> to supply the traveling wheels <NUM> and the caster wheel <NUM> with drive power.

The traveling wheel <NUM> may rotate to move the main body <NUM>, and may include a left traveling wheel 122a arranged to a left side of the main body <NUM> on the basis of a front part (X-axis direction) of the main body <NUM>, and a right traveling wheel 122b arranged to a right side of the main body <NUM>.

By rotation of the traveling wheel <NUM>, the main body <NUM> may move forward or backward or may rotate. For example, when both the left and right traveling wheels 122a and 122b rotate while moving forward, the main body <NUM> may move straight in a forward direction. When both the left and right traveling wheels 122a and 122b rotate while moving backward, the main body <NUM> may move straight in a backward direction.

In addition, if the left and right traveling wheels 122a and 122b rotate at different speeds while rotating in the same direction, the main body <NUM> may perform curvilinear traveling to the right or left. When the left and right traveling wheels 122a and 122b rotates in different directions, the main body <NUM> may rotate clockwise or counterclockwise.

The wheel motor <NUM> may generate rotational force to rotate the traveling wheel <NUM>. Although the wheel motor <NUM> may be implemented as a DC or BLDC motor, the scope or spirit of the wheel motor <NUM> for use in the robot cleaner <NUM> according to the embodiments is not limited thereto in the same manner as in other motors contained in the robot cleaner <NUM>.

The wheel motor <NUM> may include a left wheel motor 121a configured to rotate the left traveling wheel 122a and a right wheel motor 121b configured to rotate the right traveling wheel 122b.

The left and right wheel motors 121a and 121b may independently operate according to a control signal of the controller <NUM>, and the main body <NUM> may move forward or backward or rotate according to operations of the left and right wheel motors 121a and 121b.

The caster wheel <NUM> is installed at the bottom of the main body <NUM> so that the caster wheel <NUM> may rotate in response to a movement direction of the main body <NUM>. In addition, the caster wheel <NUM> may cause the main body <NUM> to move while maintaining a stable posture.

The traveling portion <NUM> may further include a caster wheel motor (not shown) configured to generate rotational force to be supplied to the caster wheel <NUM>.

The cleaning portion <NUM> may include a brush module <NUM> to scatter dust or foreign substances from the floor to be cleaned, and a suction module <NUM> to suction the scattered dust or foreign substances.

The brush module <NUM> may include a brush 131b rotating to scatter dust or foreign substances accumulated on the floor to be cleaned, and a brush motor 131a to generate rotational force to be supplied to the brush 131b. In this case, the brush 131b may also be referred to as a drum brush as necessary.

The brush 131b may be provided at a suction inlet <NUM> formed at the bottom of the main body <NUM>, and rotates about a rotation axis (parallel to a Y-axis direction) perpendicular to a forward direction (X-axis direction) of the main body <NUM> so that the dust from the floor to be cleaned is scattered into the suction inlet <NUM>.

The suction module <NUM> may suction the dust scattered by the brush 131b into a dust box <NUM>, and may include a suction fan 132b to generate suction force needed to suction the dust into the dust box <NUM> and a suction motor 132a to generate drive power needed to rotate the suction fan 132b.

The sensing portion <NUM> may include an obstacle sensor <NUM> to detect an obstacle existing in a cleaning region to be cleaned, an image sensor <NUM> to acquire peripheral images of the cleaning region, and a wheel sensor <NUM> to detect revolutions per minute (RPM) of the wheel motor <NUM>.

The obstacle sensor <NUM> may detect the presence or absence of an obstacle existing on a traveling route of the robot cleaner <NUM>. The obstacle may refer to all kinds of objects that protrude from the bottom of the cleaning space and obstruct movement of the robot cleaner <NUM>. For example, the obstacle may include furniture such as a table or sofa, and may also include the surface of a wall through which the cleaning space is divided. In addition, the obstacle may further include an object, such as a threshold (doorstep) or a round bar, through which the robot cleaner <NUM> moves upward or downward.

In more detail, the obstacle sensor <NUM> may non-contactively detect the presence or absence of an obstacle using infrared light, visible light, or electromagnetic waves such as ultrasonic waves. For example, the obstacle sensor <NUM> may emit infrared light, detect the infrared light reflected from the obstacle, and output intensity of the detected infrared light or a Time Of Flight (TOF) difference between the emitted infrared light and the reflected infrared light to the controller no. The controller no may recognize the presence or absence of an obstacle on the basis of the output value of the obstacle sensor <NUM>, or may calculate a distance between the robot cleaner <NUM> and the obstacle on the basis of the output value of the obstacle sensor <NUM>.

The obstacle sensor <NUM> may include an emitting portion 141a to emit electromagnetic waves and a receiving portion 141b to receive the electromagnetic waves reflected from the obstacle. The emitting portion 141a may be provided at a front part of the main body <NUM>, and may emit electromagnetic waves in a forward direction of the main body <NUM>. In addition, the emitting portion 141a may include a light emitting diode (LED) to generate electromagnetic waves and a wide-angle lens to scatter the electromagnetic waves in various directions by refracting the generated electromagnetic waves.

The user interface <NUM> may include an input portion <NUM> to receive a control command from the user, and a display portion <NUM> to display one screen showing a state of the robot cleaner <NUM> or the other screen guiding the user to input a control command.

The control command entered by the user through the input portion <NUM> may include a command for selecting any one of cleaning modes composed of an automatic cleaning mode and a manual cleaning mode, and a command for selecting a suction mode. For example, the suction mode may include three modes, i.e., a first mode, a second mode, and a third mode. The suction force may increase in the order of the first mode → the second mode → the third mode. In more detail, the first mode may be a quiet mode, the second mode may be a normal mode, and the third mode may be a turbo mode.

The input portion <NUM> may include a push switch to generate an input signal by detecting user pressurization, a membrane switch, or a touch switch to generate an input signal by detecting contact of some parts of a user's body.

Although not shown in the drawings, the input portion <NUM> may further include a remote controller capable of remotely controlling the robot cleaner <NUM>.

The display portion <NUM> may be implemented as a display panel, for example, a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, or the like. In addition, each of the display portion <NUM> and the input portion <NUM> may also function as a touchscreen as necessary.

Based on the user control command and the detection result or output value of the sensing portion <NUM>, the controller <NUM> may control the traveling portion <NUM> and the cleaning portion <NUM>. A detailed control operation of the controller <NUM> will be described later.

The controller <NUM> may include an input/output (I/O) interface <NUM> to perform mediation of data communication between the controller <NUM> and various constituent elements contained in the robot cleaner <NUM>, a memory <NUM> to store a program and data therein, a graphics processor <NUM> to perform image processing, a main processor <NUM> to perform a calculation operation according to the program and data stored in the memory <NUM>, and a system bus <NUM> used as a data communication path among the I/O interface <NUM>, the memory <NUM>, the graphics processor <NUM>, and the main processor <NUM>.

The I/O interface <NUM> may receive the detection result of the sensing portion <NUM>, i.e., the output value of the sensing portion <NUM>. The I/O interface <NUM> may transmit the received detection result or output value of the sensing portion <NUM> to the main processor <NUM>, the graphics processor <NUM>, and the memory <NUM>.

In addition, the I/O interface <NUM> may transmit a control signal generated from the main processor <NUM> to the traveling portion <NUM> and the cleaning portion <NUM>.

The memory <NUM> may retrieve a control program and data needed to control the operation of the robot cleaner <NUM> from the storage portion <NUM> and store the retrieved control program and data, or may temporarily store the detection result of the sensing portion <NUM> or the like.

The memory <NUM> may include volatile memories such as SRAM, DRAM, or the like. However, the scope or spirit of the present invention is not limited thereto. If necessary, the memory <NUM> may include non-volatile memories, for example, a flash memory, an Erasable Programmable Read Only Memory (EPROM), etc..

The graphic processor <NUM> may convert an image acquired from the image sensor <NUM> into a format capable of being stored in the memory <NUM> or the storage portion <NUM>, or may change a resolution or size of the image acquired from the image sensor <NUM>.

The main processor <NUM> may process the detection result of the sensing portion <NUM> according to the program and data stored in the memory <NUM>, or may perform the calculation operation for controlling the traveling portion <NUM> and the cleaning unit <NUM>.

For example, the main processor <NUM> may detect a floor state according to the detection result of the sensing portion <NUM>, and may generate a control signal for controlling the suction force of the suction module <NUM> on the basis of the detected floor state.

The main processor <NUM> may calculate the position of the robot cleaner <NUM> on the basis of the image obtained from the image sensor <NUM>, or may calculate the direction, distance, and size of the obstacle on the basis of the output value of the obstacle sensor <NUM>.

In addition, the main processor <NUM> may perform operations needed to determine whether the obstacle will be avoided according to the direction, distance, and size of the obstacle or to determine whether the robot cleaner <NUM> will contact the obstacle. If it is expected that the robot cleaner <NUM> will avoid the obstacle, the main processor <NUM> may calculate the traveling route for avoiding the obstacle. If it is expected that the robot cleaner <NUM> will contact the obstacle, the main processor <NUM> may calculate the traveling route for arranging the obstacle and the robot cleaner <NUM>.

The main processor <NUM> may generate a control signal to be provided to the traveling portion <NUM> in such a manner that the robot cleaner <NUM> may move along the calculated traveling route.

The storage portion <NUM> may include a non-volatile memory, for example, a magnetic disk, a Solid State Drive (SSD), a Read Only Memory (ROM), an Erasable Programmable Read Only Memory (EPROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), etc. If necessary, the storage portion <NUM> may further include the above-mentioned volatile memory.

The storage portion <NUM> may permanently store the control program and data needed to control the operation of the robot cleaner <NUM>, and may also store a cleaning map generated based on the image acquired by the image sensor <NUM>.

<FIG> is a conceptual diagram illustrating a method for allowing the robot cleaner to control the suction force according to floor states according to an embodiment of the present disclosure.

As described above, the controller <NUM> may control the suction module <NUM> to have different suction forces according to floor states. For example, when the floor state is the soft floor, the controller <NUM> may control the suction module <NUM> to have a higher suction force as compared to the other case in which the floor state is the hard floor. In more detail, as shown in <FIG>, when the floor state is the soft floor, the controller <NUM> may control the suction module <NUM> to have the suction force of <NUM>%. When the floor state is the hard floor, the controller <NUM> may control the suction module <NUM> to have the suction force of <NUM>%. In addition, when the floor state is a dusty floor state, the controller <NUM> may control the suction module <NUM> to have the suction force of <NUM>%.

In this case, a reference for indicating the suction force may be a maximum output level of the suction motor 132a. For example, assuming that the maximum output level of the suction motor 132a is <NUM> watts(W), when the floor state is the soft floor, the suction module <NUM> may suction dust at the output level of 49W. Assuming that the maximum output level of the suction motor 132a is <NUM> watts(W), when the floor state is the hard floor, the suction module <NUM> may suction dust at the output level of 14W. Assuming that the maximum output level of the suction motor 132a is <NUM> watts(W), when the floor state is a dusty floor, the suction module <NUM> may suction dust at the maximum output level of 70W.

However, the suction forces of the respective floor states shown in <FIG> are only an example capable of being applied to the robot cleaner <NUM>, and the scope or spirit of the robot cleaner <NUM> is not limited thereto.

The suction force for each floor state may be established in advance. After the suction force for each floor state has been established, the suction force for each floor state may also be changed by the user as necessary.

Meanwhile, the controller <NUM> may also control not only the suction force of the suction module <NUM> but also the traveling route of the robot cleaner <NUM> on the basis of the floor states. A detailed description thereof will hereinafter be given with reference to the attached drawings.

<FIG> are views illustrating various examples for allowing the robot cleaner to control a traveling route according to floor states according to an embodiment of the present disclosure. <FIG> is a conceptual diagram illustrating a priority cleaning mode for the soft floor, <FIG> is a conceptual diagram illustrating a repeated cleaning mode for the soft floor, and <FIG> is a conceptual diagram illustrating an omitted cleaning mode for the soft floor.

In <FIG>, it is assumed that the robot cleaner <NUM> performs cleaning and traveling according to the automatic cleaning mode.

Referring to <FIG>, when the controller <NUM> determines the floor state to be the soft floor (SF) while cleaning and traveling about a cleaning region R, the controller <NUM> may control the traveling route of the robot cleaner <NUM> to perform priority cleaning of a region corresponding to the soft floor (SF).

To this end, the controller <NUM> may determine the floor state in real time or at intervals of a predetermined time.

In more detail, when the robot cleaner <NUM> travels over (or crosses) a border B between the region corresponding to the hard floor and the region corresponding to the soft floor while cleaning and traveling about the hard floor region, the controller <NUM> may determine that the floor state is changed from the hard floor to the soft floor.

The controller <NUM> may control the suction force of the suction module <NUM> to have suction force corresponding to the soft floor. In more detail, the controller <NUM> may increase the suction force of the suction module <NUM> by increasing the output of the suction motor 132a.

When the robot cleaner <NUM> travels over (or crosses) the border B between the hard floor region and the soft floor region while cleaning and traveling about the soft floor region, the controller <NUM> may determine that the floor state is changed from the soft floor to the hard floor.

In this case, the controller <NUM> may control the traveling direction of the robot cleaner <NUM> to rotate by <NUM>°, such that the robot cleaner <NUM> may re-enter the soft floor region. In more detail, the controller <NUM> may control the traveling direction by transmitting a control signal to the traveling portion <NUM>.

As described above, when the robot cleaner <NUM> moves from the soft floor region to the hard floor region, the controller <NUM> may detect such movement toward the hard floor region and then control the robot cleaner <NUM> to re-enter the soft floor region, such that the controller <NUM> may control the robot cleaner <NUM> to perform priority cleaning of the soft floor region by repeating the above movement detection and re-entry to the soft floor region.

When the priority cleaning of the soft floor region is completed, the controller <NUM> may clean the remaining hard floor region from among the entire cleaning region R. When the robot cleaner re-enters the hard floor region after completion of the priority cleaning of the soft floor region, the controller <NUM> may again reduce the suction force of the suction module <NUM>.

During the cleaning and traveling mode of the robot cleaner <NUM>, the image sensor <NUM> may acquire an image of the cleaning region R to be cleaned, and the controller <NUM> may generate a cleaning map on the basis of the acquired image. The generated cleaning map may be stored in the storage portion <NUM>.

Alternatively, as shown in <FIG>, when the controller <NUM> determines the floor state to be the soft floor while the robot cleaner <NUM> cleans and travels about the cleaning region R, the controller <NUM> may repeatedly clean the soft floor region after completion of the cleaning and traveling operation along an original traveling route.

The controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the hard floor about the entire cleaning region R. When the robot cleaner <NUM> cleans the hard floor region while cleaning and traveling about the entire cleaning region R, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the hard floor. When the robot cleaner <NUM> cleans the soft floor region, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the soft floor.

As described in the above-mentioned example, during the cleaning and traveling operation of the robot cleaner <NUM>, the image sensor <NUM> may acquire an image of the entire cleaning region R, and the controller <NUM> may generate a cleaning map on the basis of the acquired image. The generated cleaning map may be stored in the storage portion <NUM>, and the cleaning map may include information regarding the floor state of the cleaning region R.

Upon completion of the cleaning and traveling operation about the entire cleaning region R, the controller <NUM> may control the robot cleaner <NUM> to re-enter the soft floor region by controlling the traveling portion <NUM>. In this case, the controller <NUM> may use the cleaning map stored in the storage portion <NUM>. When the robot cleaner <NUM> enters the soft floor region, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the soft floor.

As shown in <FIG>, the robot cleaner <NUM> may repeatedly clean the soft floor region having a high resistance in suction of dust or foreign substances, thereby increasing cleaning efficiency.

Alternatively, as shown in <FIG>, when the controller <NUM> determines the floor state to be the soft floor while the robot cleaner <NUM> cleans and travels about the cleaning region R, the controller <NUM> may perform omitted cleaning in which the soft floor region is omitted from the entire cleaning region R and thus the robot cleaner <NUM> cleans only the remaining region other than the soft floor region.

When the robot cleaner <NUM> enters the soft floor region by crossing the border B between the hard floor region and the soft floor region while cleaning and traveling about the hard floor region, the controller <NUM> may determine that the floor state is changed from the hard floor to the soft floor.

In this case, the controller <NUM> may rotate the traveling direction of the robot cleaner <NUM> by <NUM>°, such that the robot cleaner <NUM> may re-enter the hard floor region. In more detail, the controller <NUM> may control the traveling direction of the robot cleaner <NUM> by transmitting a control signal to the traveling portion <NUM>.

As described above, when the robot cleaner <NUM> moves from the hard floor region to the soft floor region, the controller <NUM> may detect such movement toward the soft floor region and then control the robot cleaner <NUM> to re-enter the hard floor region, such that the controller <NUM> may omit cleaning of the soft floor region by repeating the above movement detection and re-entry to the hard floor region.

Since the soft floor region is not cleaned by the robot cleaner <NUM>, the suction module <NUM> may be controlled by the suction force corresponding to the hard floor.

As illustrated in the example of <FIG>, the robot cleaner <NUM> omits the soft floor region from the entire cleaning region to be cleaned, quickly cleans only the hard floor region using a low suction force, and directs the user to manually clean the soft floor region, such that a battery lifetime of the robot cleaner <NUM> may increase and the robot cleaner <NUM> may perform efficient cleaning about the cleaning region to be cleaned.

<FIG> is a conceptual diagram illustrating a method for allowing the robot cleaner to control an exemplary case in which the robot cleaner detects a fall. <FIG> is a conceptual diagram illustrating a method for allowing the robot cleaner to control an exemplary case in which the environment stored in the cleaning map is changed.

The sensing portion <NUM> may further include a fall prevention sensor (not shown) configured to prevent the robot cleaner <NUM> from falling during traveling of the robot cleaner <NUM>. As one example of the fall prevention sensor, an infrared sensor may be used. The fall prevention sensor may emit infrared light to the floor surface, and may receive the infrared light reflected from the floor surface, such that the fall prevention sensor may detect the distance to the floor surface.

If the detected distance is equal to or longer than a predetermined distance, the controller <NUM> may determine the presence of a high possibility of falling of the robot cleaner <NUM> as shown in <FIG>, such that the controller <NUM> may transmit a fall sensing signal for indicating a high risk of falling of the robot cleaner <NUM> to the controller <NUM>, and the controller <NUM> may move the main body <NUM> in a backward direction such that the controller <NUM> may prevent the robot cleaner <NUM> from falling.

In this case, the controller <NUM> may control the robot cleaner <NUM> to move by different backward movement distances according to various states of the floor surface on which the robot cleaner <NUM> travels. In more detail, when the floor state is the soft floor, the controller <NUM> may increase the backward movement distance of the robot cleaner <NUM> as compared to the other case in which the floor state is the hard floor. For example, when the floor state is the hard floor and a high risk of falling of the robot cleaner <NUM> is detected, the controller <NUM> may control the robot cleaner <NUM> to move backward by <NUM>. When the floor state is the soft floor and a high risk of falling of the robot cleaner <NUM> is detected, the controller <NUM> may control the robot cleaner <NUM> to move backward by <NUM>.

As a result, although slip of the traveling wheel <NUM> occurs in the soft floor environment, the robot cleaner <NUM> may safely move backward.

Referring to <FIG>, when the robot cleaner <NUM> finishes cleaning of the cleaning region R, the robot cleaner <NUM> returns to a docking station <NUM> and is then charged with electricity through the docking station <NUM>. Thereafter, when the robot cleaner <NUM> performs re-cleaning of the soft floor region on the basis of the cleaning map, if the position stored as the soft floor region in the cleaning map does not correspond to the soft floor region, the robot cleaner <NUM> may again return to the docking station <NUM> without cleaning the soft floor region or may clean the entirety of the cleaning region R.

In more detail, after the robot cleaner <NUM> finishes cleaning of the cleaning region R, the user may intentionally move the carpet to the outside of the cleaning region R. In this case, when the robot cleaner <NUM> arrives at the position stored as the soft floor region in the cleaning map, the sensing portion <NUM> may detect the floor state. When the detected floor state is not identical to the soft floor, the robot cleaner <NUM> may again return to the docking station <NUM>, or may return to the docking station <NUM> after finishing cleaning of the entire cleaning region R. When the detected floor state is the soft floor, the robot cleaner <NUM> may clean the corresponding region.

As described above, after the entire cleaning region R is completely cleaned, the robot cleaner <NUM> returns to the docking station <NUM> and is then charged with electricity. Whereas a conventional robot cleaner has been designed to perform re-cleaning of the cleaning region after an internal battery thereof is fully charged with electricity, the robot cleaner <NUM> according to the embodiment may move to the cleaning region R as soon as an internal battery thereof is charged with as much electricity as it needs and may thus perform re-cleaning of the cleaning region R.

To this end, the controller <NUM> may calculate a charging ratio needed to clean the cleaning region R on the basis of the cleaning map stored in the storage portion <NUM>. In more detail, the cleaning map may include information regarding the ratio of the soft floor region to the cleaning region R and information regarding the ratio of the hard floor region to the cleaning region R. The controller <NUM> may calculate the charging ratio needed to clean the cleaning region R using the suction force corresponding to the soft floor region, the suction force corresponding to the hard floor region, and the ratio of two regions (i.e., the soft floor region and the hard floor region). For example, under the condition that the calculation result indicates the charging ratio of <NUM>%, although the robot cleaner <NUM> having returned to the docking station <NUM> is charged with electricity of <NUM>% to <NUM>%, the controller <NUM> may control the robot cleaner <NUM> to move back to the cleaning region R such that the robot cleaner <NUM> may perform re-cleaning of the cleaning region R.

<FIG> is a conceptual diagram illustrating a method for allowing the robot cleaner to move according to a point cleaning operation according to an embodiment of the present disclosure. <FIG> is a conceptual diagram illustrating a traveling route used in an exemplary case in which the robot cleaner detects a soft floor while in motion according to the point cleaning operation.

As described above, the input portion <NUM> of the robot cleaner <NUM> may include a remote controller <NUM>.

Referring to <FIG>, the remote controller <NUM> may include an input portion <NUM> to receive a control command from the user, and an emitting portion <NUM> to emit visible light and infrared light according to the user control command.

The visible light emitted from the emitting portion <NUM> may form a light spot (LS) at a user-designated position, such that feedback information regarding the user-designated position is supplied to the user. The infrared light emitted from the emitting portion <NUM> may transmit the user-designation position information and the user control command to the robot cleaner <NUM>.

The robot cleaner <NUM> may include a light reception portion (not shown) configured to receive the infrared light emitted from the emitting portion <NUM> of the remote controller <NUM>, and the controller <NUM> may control the robot cleaner <NUM> to travel along a movement route of the light spot (LS) on the basis of the infrared light received by the light reception portion.

Referring to <FIG>, when the robot cleaner <NUM> enters the soft floor region while moving along the light spot (LS) so as to perform point cleaning, the robot cleaner <NUM> performs priority cleaning about the soft floor region and then again returns to the movement route of the light spot (LS).

When the robot cleaner <NUM> enters the soft floor region, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the soft floor. In addition, when the robot cleaner <NUM> re-enters the hard floor region, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the hard floor.

<FIG> is a conceptual diagram illustrating an exemplary case in which the robot cleaner performs cleaning and traveling while simultaneously tracing a wall surface according to an embodiment of the present disclosure. <FIG> is a conceptual diagram illustrating a method for allowing the robot cleaner to control suction force according to a floor state and information as to whether a wall surface is traced according to an embodiment of the present disclosure.

Referring to <FIG>, the robot cleaner <NUM> may perform the cleaning traveling mode while simultaneously tracing the wall surface W. In more detail, when the robot cleaner <NUM> detects the wall surface W during the cleaning traveling mode of the robot cleaner <NUM>, the robot cleaner <NUM> may perform cleaning while simultaneously traveling along the detected wall surface W.

When the robot cleaner <NUM> moves from the hard floor region to the soft floor region during the cleaning traveling mode based on the wall tracing manner, the controller <NUM> may detect entry to the soft floor region and may control the suction module <NUM> to have the suction force corresponding to the wall surface and the soft floor as shown in <FIG>. In other words, when the robot cleaner <NUM> cleans and travels about the soft floor region while simultaneously tracing the wall surface, the controller <NUM> may control the suction module <NUM> to have a third-level suction force. Assuming that the suction force corresponding to the soft floor is referred to as a second-level suction force and the suction force corresponding to the hard floor is referred to as a first-level suction force, the suction forces of the first to third levels may be denoted by "first-level suction force < second-level suction force < third-level suction force". For example, the third-level suction force may be set to the suction force of <NUM>%.

When the robot cleaner <NUM> enters the soft floor region while simultaneously tracing the wall surface as shown in <FIG> and <FIG>, the suction force of the robot cleaner <NUM> increases to maximum suction force such that the wall surface W and the floor are brought into contact with each other, resulting in increased cleaning efficiency in the soft floor region.

<FIG> is a view illustrating a blade structure of the robot cleaner according to an embodiment of the present disclosure.

Referring to <FIG>, the suction inlet <NUM> is provided with a blade <NUM> for directing the dust scattered by the brush 131b into the dust box <NUM>. The blade <NUM> may be arranged at the rear of the brush 131b, and may be formed of a flexible material such as rubber.

The blade <NUM> may be tilted downward toward the floor, such that the end of the blade <NUM> may be in close contact with the floor surface during downward movement of the blade <NUM> and may be released from close contact with the floor surface during upward movement of the blade <NUM>.

A motor (not shown) configured to provide drive power through which the blade <NUM> moves upward or downward, and the controller <NUM> may transmit a control signal to the motor in such a manner that the blade <NUM> moves upward or downward.

When the controller <NUM> determines the floor state to be the soft floor during the cleaning traveling mode of the robot cleaner <NUM>, the controller <NUM> may improve suction efficiency by moving the blade <NUM> downward.

In addition, the controller <NUM> may control the suction module <NUM> to have the suction force corresponding to the soft floor.

Meanwhile, since lint or nap easily occurs in the soft floor region and dust readily accumulates between carpet yarns in the soft floor region, a relatively large amount of dust may generally occur in the soft floor region during the cleaning traveling mode of the robot cleaner <NUM> as compared to the hard floor region. Therefore, after completion of the cleaning about the cleaning region R, when the ratio of the soft floor region to the cleaning region R is equal to or higher than a predetermined reference, the controller <NUM> may output an instruction signal for guiding the user to empty the dust box <NUM>. For example, the instruction signal may be output through the display portion <NUM>.

<FIG> are conceptual diagrams illustrating examples in which the robot cleaner informs the user of soft floor detection according to an embodiment of the present disclosure.

The robot cleaner <NUM> may visually display detection of the soft floor. The detection of the soft floor may indicate execution of high-suction-force cleaning. For example, as shown in <FIG>, in order to indicate the detection state of the soft floor, a bar-shaped symbol may be displayed as a bold bar on the display portion <NUM>. In another example, as shown in <FIG>, visible light may be projected onto the floor so as to indicate the detection state of the soft floor. In another example, as shown in <FIG>, a light source <NUM> mounted to a top surface of the robot cleaner <NUM> may be driven to indicate the detection state of the soft floor.

In order to project the visible light onto the floor, an electromagnetic emitting portion 141a of the obstacle sensor <NUM> may be used. In another example, an additional light source <NUM> mounted to a lower part of the robot cleaner <NUM> may also be used as shown in <FIG>. For example, the light sources <NUM> and <NUM> may be implemented as LEDs.

In addition, the detection state of the soft floor may also be audibly indicated through a speaker (not shown) mounted to the robot cleaner <NUM>.

The user may recognize a current suction force of the robot cleaner through the above visual or audible information, and may also recognize whether or not the robot cleaner <NUM> normally operates. As a result, the user may take appropriate measures for efficient cleaning.

For example, when information regarding the detection state of the soft floor is not supplied to the user even though the robot cleaner <NUM> enters the carpet region, the user may recognize the fact that the robot cleaner <NUM> has not detected the presence of the carpet, such that the user may directly clean the carpet region without using the robot cleaner <NUM> as necessary.

The above-mentioned embodiments have exemplarily disclosed that the robot cleaner <NUM> controls the suction force and the traveling route according to a state of the floor to be cleaned by the robot cleaner <NUM>. A method for allowing the robot cleaner <NUM> to recognize the floor state according to the embodiment of the present disclosure will hereinafter be described in detail.

Referring back to <FIG>, the sensing portion <NUM> may include a wheel sensor <NUM> to detect load applied to the traveling wheel <NUM>.

When load is applied to the traveling wheel <NUM>, the RPM of the wheel motor <NUM> increases, such that the wheel sensor <NUM> may be implemented as an encoder configured to measure the motor RPM.

In addition, the wheel sensor <NUM> may include a left wheel sensor mounted to the left wheel motor 121a so as to independently detect the RPM of the left wheel motor 121a, and a right wheel sensor mounted to the right wheel motor 121b so as to independently detect the RPM of the right wheel motor 121b.

The controller <NUM> may recognize the floor state on the basis of load applied to the traveling wheel <NUM>. For example, when the load applied to the traveling wheel <NUM> is equal to or higher than a predetermined reference value, the controller <NUM> may determine the floor state to be the soft floor. When the load applied to the traveling wheel <NUM> is less than the predetermined reference value, the controller <NUM> may determine the floor state to be the hard floor.

<FIG> is a graph illustrating the relationship between an encoder output and a duty ratio according to floor states.

Referring to <FIG>, when load is applied to the traveling wheel <NUM> according to the floor state, the RPM of the wheel motor <NUM> may be reduced and a duty ratio of the wheel motor <NUM> may be increased by Proportional Integral Derivative (PID) control. That is, when the floor state is the soft floor and the load applied to the traveling wheel <NUM> increases, the encoder output may be reduced and the duty ratio may be increased.

The relationship between the encoder output and the duty ratio may be denoted by a gradient (g) of the graph shown in <FIG>. When the gradient (g) is equal to or higher than a predetermined reference value (Th<NUM>), the controller <NUM> may determine the floor state to be the hard floor. When the gradient (g) is less than the predetermined reference value (Th<NUM>), the controller <NUM> may determine the floor state to be the soft floor.

Meanwhile, in order to reflect a weight-based linear velocity, the gradient variation (△g) may be calculated by the following equation <NUM>. A difference (△Diff. ) between a measurement value and a calculated value may be calculated by the following equation <NUM>.

In Equation <NUM>, 'g' may be denoted by "g = Encoder Output / Duty Ratio", and '△w' may be a weight based on the linear velocity and be allocated by a developer.

In Equation <NUM>, E may denote the encoder output.

<FIG> is a graph illustrating encoder outputs and calculation values of the controller when the floor state is the hard floor. <FIG> is a graph illustrating encoder outputs and calculation values of the controller when the floor state is a soft floor.

When the floor state is a smooth hard floor such as a wooden floor or a tiled floor, the encoder output (E), the gradient variation (△g), and the difference (△Diff. ) between the encoder output (E) and the gradient variation (△g) are as shown in the graph of <FIG>.

When the floor state is the soft floor such as a carpet, the encoder output (E), the gradient variation (△g), and the difference (△Diff. ) between the encoder output (E) and the gradient variation (△g) are as shown in the graph of <FIG>.

The controller <NUM> may recognize the floor state by comparing a predetermined reference value (Th<NUM>) with the difference (△Diff. Referring to <FIG>, when the difference (△Diff. ) is equal to or higher than the reference value (Th<NUM>), the controller <NUM> may determine the floor state to be the soft floor. When the difference (△Diff. ) is less than the reference value (Th<NUM>), the controller <NUM> may determine the floor state to be the hard floor.

In this case, the reference value (Th<NUM>) may be predetermined through experiments or simulations.

Meanwhile, the controller <NUM> may further reflect the duty ratio variation caused by reduction of a battery voltage as necessary, and a detailed description thereof will hereinafter be given with reference to <FIG> and <FIG>.

<FIG> is a graph illustrating floor states and duty ratios for each battery voltage. <FIG> is a graph illustrating a deviation between the duty ratios for each battery voltage.

Referring to <FIG>, when a battery voltage (v) for supplying a power-supply voltage to the robot cleaner <NUM> is reduced, the duty ratio (d) may be increased to compensate for the reduced battery voltage. In addition, as described above, as the load applied to the traveling wheel <NUM> gradually increases according to the floor state, the duty ratio (d) may also increase.

If a deviation (△d) of the duty ratios of the respective battery voltages is denoted by a quadratic equation, the resultant graph shown in <FIG> may be obtained. The controller <NUM> may calculate the deviation (△d) of the duty ratios based on battery voltages, and may use an expression "d - △d" as the duty ratio needed to calculate Equation <NUM> and Equation <NUM>.

<FIG> is a conceptual diagram illustrating an exemplary case in which the robot cleaner is located at a border between the soft floor region and the hard floor region according to an embodiment of the present disclosure.

Meanwhile, the controller <NUM> may apply the above calculation and decision process to each of the left traveling wheel 122a and the right traveling wheel 122b. When the decision results of the left traveling wheel 122a and the right traveling wheel 122b indicate the soft floor, the controller <NUM> may determine that two traveling wheels 122a and 122b of the robot cleaner <NUM> are located in the soft floor region. When the decision results of the left traveling wheel 122a and the right traveling wheel 122b indicate the hard floor, the controller <NUM> may determine that two traveling wheels 122a and 122b of the robot cleaner <NUM> are located in the hard floor region.

However, as shown in <FIG>, it should be noted that one 122a of the two traveling wheels 122a and 122b may be located in the soft floor region and the other one 122b may be located in the hard floor region without departing from the scope or spirit of the present disclosure. As described above, the controller <NUM> may independently apply the above calculation and decision process to each of the two traveling wheels 122a and 122b, such that the controller <NUM> is able to perform correct decision even when the two traveling wheels 122a and 122b are located in different regions.

If necessary, the controller <NUM> may combine the decision result based on the load applied to the traveling wheel <NUM> with the decision result based on the load applied to the brush 131b, such that the controller <NUM> may also obtain the final decision in a complementary manner. A detailed description thereof will hereinafter be given with reference to <FIG>.

<FIG> is a control block diagram illustrating a robot cleaner further including a current sensor. <FIG> is a graph illustrating an exemplary current measured by a current sensor.

Referring to <FIG>, the robot cleaner <NUM> according to one embodiment may further include a current sensor <NUM> configured to measure a current of the brush motor 131a.

When the floor state is the soft floor, load is applied not only to the traveling wheel <NUM> but also to the brush 131b. When the load is applied to the brush 131b, a current flowing in the motor 131a may increase.

Therefore, the controller <NUM> may recognize the floor state by comparing the current measured by the current sensor <NUM> with a predetermined reference value (Th<NUM>). As shown in <FIG>, when the current measured by the current sensor <NUM> is equal to or higher than a predetermined reference value (Th<NUM>), the controller <NUM> may determine the floor state to be the soft floor. When the current measured by the current sensor <NUM> is less than the predetermined reference value (Th<NUM>), the controller <NUM> may determine the floor state to be the hard floor.

<FIG> is a graph illustrating an exemplary current measured for each floor state.

Referring to <FIG>, although the floor states are actually different from each other, the current values measured by the current sensor <NUM> on the different floor states may unexpectedly overlap with each other such that it may be difficult to discriminate among the measurement current values due to overlapping of the current values. For example, when the brush 131b is spaced apart from the floor surface due to pitching of the robot cleaner <NUM>, it may be impossible to measure a correct current in which the floor state is reflected.

In more detail, when the robot cleaner <NUM> travels over the obstacle <NUM> such as a threshold, the brush 131b mounted to the bottom of the front part of the robot cleaner <NUM> may be floated on the floor. Therefore, erroneous information may be included in the floor-state decision result based on the load applied to the brush 131b.

In another example, when the carpet spread on the floor is formed in a cut pile shape and the length of yarn is in the range of <NUM> to <NUM>, both traveling wheels 122a and 122b are affected by carpet yarns and are located at different heights with respect to the floor surface, or when the carpet yarns are pressed down and squashed in the traveling direction of the robot cleaner <NUM> and rotate in the same direction as the traveling direction, erroneous information may be included in the floor-state decision result based on the load applied to the brush 131b, but the other decision result based on the load applied to the traveling wheel <NUM> may be considered reliable.

In contrast, erroneous information may be contained in the decision result based on the load applied to the traveling wheel <NUM>, and the other decision result based on the load applied to the brush 131b may be considered reliable as necessary.

For example, if he carpet spread on the floor is formed in a loop pile shape, there is a possibility that erroneous information may be contained in the decision result based on the load applied to the traveling wheel <NUM>.

When at least one of the decision result based on the load applied to the traveling wheel <NUM> and the other decision result based on the load applied to the brush 131b indicates the soft floor, the controller <NUM> may finally determine the floor state to be the soft floor.

In other words, when at least one of the load applied to the traveling wheel <NUM> and the other load applied to the brush 131b is equal to or higher than the corresponding reference value (first reference value or second reference value), the controller <NUM> may determine the floor state to be the soft floor.

<FIG> is a control block diagram illustrating a robot cleaner further including an acceleration sensor.

Referring to <FIG>, the sensing portion <NUM> of the robot cleaner <NUM> may further include an acceleration sensor <NUM> configured to measure acceleration of the main body <NUM>. The acceleration sensor <NUM> may measure acceleration (dx) associated with an X-axis corresponding to a forward direction of the main body <NUM> and acceleration (dz) associated with a Z-axis corresponding to a height direction of the main body <NUM>.

The controller <NUM> may monitor the output of the acceleration sensor <NUM> in real time. If the acceleration parameters dx and dz are abruptly increased, the controller <NUM> may determine that the robot cleaner <NUM> quickly starts operation or suddenly stops operation.

After the acceleration parameters dx and dz are abruptly increased and then reduced, if the acceleration parameters dx and dz are abruptly re-increased at intervals of a predetermined time, the controller <NUM> may determine that the robot cleaner <NUM> travels over the obstacle such as a threshold and then moves down.

For example, when the robot cleaner <NUM> travels over the obstacle, load similar to a load generated when the robot cleaner <NUM> moves from the hard floor region to the soft floor region may be applied to the traveling wheel <NUM>. Therefore, there is a possibility that the decision result based on the load applied to the traveling wheel <NUM> has difficulty in discriminating between the first case in which the robot cleaner <NUM> travels over the obstacle and the second case in which the robot cleaner <NUM> moves from the hard floor region to the soft floor region.

However, the output signals of the acceleration sensor having detected the above two cases may indicate different results, such that the controller <NUM> may filter out the first case in which the robot cleaner <NUM> travels over the obstacle on the basis of the output signal of the acceleration sensor <NUM>.

In more detail, when the X-axis directional acceleration and the Z-axis directional acceleration are abruptly increased, the controller <NUM> determines that the robot cleaner <NUM> travels over the obstacle such that the controller no turns off the wheel sensor <NUM>. Alternatively, although the decision result based on the output of the wheel sensor <NUM> indicates the soft floor, the controller <NUM> may not perform the suction force control and traveling route control corresponding to the soft floor.

In addition, the controller <NUM> may apply the output of the wheel sensor <NUM> to the suction force control only when the robot cleaner <NUM> has a traveling speed equal to or higher than a predetermined speed, the sensed result or the suction force control may have higher reliability. For example, the predetermined speed may be <NUM>/s. In more detail, only when the traveling speed of the robot cleaner <NUM> is equal to or higher than a predetermined reference speed, the controller <NUM> may detect load applied to the traveling wheel <NUM> using the wheel sensor <NUM>, and may apply the detected load to the suction force control. When the traveling speed of the robot cleaner <NUM> is less than the reference speed, the controller <NUM> may detect load applied to the brush 131b and apply the detected load to the suction force control, or may not perform the suction force control as necessary.

If the robot cleaner <NUM> rotates clockwise or counterclockwise to change the traveling direction or if the robot cleaner <NUM> remains stationary at one place, the controller <NUM> may not change the suction force of the suction module <NUM> to another suction force. In more detail, when the position of the robot cleaner <NUM> is not changed during rotation of the traveling wheel <NUM>, the wheel sensor <NUM> may detect no load or may not use the detection result of the wheel sensor <NUM>, such that the suction force generated by the suction module <NUM> may remain unchanged. As a result, although erroneous information occurs in the load detection result of the traveling wheel <NUM> rotating clockwise or counterclockwise at one place, the controller <NUM> may prevent erroneous information from occurring in the suction force control.

<FIG> is a conceptual diagram illustrating a method for allowing the robot cleaner to control an exemplary case in which a border region between the soft floor region and the hard floor region is short in length.

Referring to <FIG>, before the robot cleaner moves by a predetermined distance after entering the hard floor region by traveling over the border B between the soft floor region (SF) and the hard floor region (HF), the robot cleaner <NUM> is bumped against the wall or obstacle (O) and is thus unable to move forward any more, the controller <NUM> may control the suction module <NUM> to have the suction force corresponding to the soft floor.

In more detail, assuming that the spacing between the border B of the two regions and the wall or obstacle in the traveling direction of the robot cleaner <NUM> is referred to as a border section, when the distance (d) to the border section is shorter than a predetermined distance, the controller <NUM> may not perform the suction force control according to change of the floor state, and may control the suction module <NUM> to have the suction force corresponding to the previous region.

Although <FIG> has exemplarily disclosed that the robot cleaner <NUM> moves from the soft floor region to the hard floor region for convenience of description, it should be noted that the robot cleaner <NUM> may also move from the hard floor region to the soft floor region as necessary.

As a result, the robot cleaner <NUM> may apply the suction force control only to the detection result obtained when the robot cleaner <NUM> travels by the predetermined distance or longer, resulting in increased reliability in the detection result.

The robot cleaner <NUM> according to one embodiment may determine the floor state by combining the load applied to the traveling wheel <NUM>, the load applied to the brush 131b, and the acceleration of the main body <NUM> with one another in a complementary manner, such that the robot cleaner <NUM> may increase accuracy in the detection result. The robot cleaner <NUM> controls battery power to be efficiently consumed by controlling the suction force according to the floor states, resulting in a maximum battery lifespan. The robot cleaner <NUM> controls the traveling route control according to the floor states, resulting in increased cleaning efficiency.

A method for controlling the robot cleaner according to one embodiment will hereinafter be described. The above-mentioned robot cleaner <NUM> may be applied to the following method for controlling the robot cleaner. Therefore, the above-mentioned explanation and drawings may also be equally applied to the following method for controlling the robot cleaner.

<FIG> is a flowchart illustrating a method for controlling the robot cleaner according to an embodiment of the present disclosure.

Referring to <FIG>, the method for controlling the robot cleaner according to one embodiment may recognize the floor state on the basis of the sensed result of the sensing portion <NUM> (<NUM>). The floor state may include a soft floor state and a hard floor state. The soft floor may refer to a floor covered with rough fabrics, such as a carpet, having higher resistance against slippage. The hard floor may refer to a smooth and hard floor such as a wooden floor, a tiled floor, etc. The floor state may be recognized by the controller <NUM>, and it is assumed that the robot cleaner <NUM> performs the cleaning traveling mode while simultaneously traveling on the floor.

The robot cleaner <NUM> may control the suction force and the traveling route on the basis of the detected floor state (<NUM>). For example, when the floor state is the soft floor, the suction force corresponding to the soft floor may be predetermined. When the floor state is the hard floor, the suction force corresponding to the hard floor may be predetermined. The suction force corresponding to the soft floor may be higher than the suction force corresponding to the hard floor. The reason why the robot cleaner <NUM> controls the traveling route is to perform efficient cleaning according to the floor state.

Meanwhile, detection of the floor state and the control process based on the detected floor state may be performed in real time during the cleaning traveling mode of the robot cleaner or may also be performed at intervals of a predetermined time during the cleaning traveling mode of the robot cleaner. For convenience of description and better understanding of the present disclosure, it is assumed that each of the flowchart of <FIG> and the following flowchart to be described later will exemplarily disclose one cycle in which the floor state decision and the control process based on the detected floor state are performed. A method for controlling the traveling route will hereinafter be described.

<FIG> is a flowchart illustrating a method for allowing the robot cleaner to perform priority cleaning of the soft floor according to an embodiment of the present disclosure. <FIG> is a flowchart illustrating a method for allowing the robot cleaner to perform repeated cleaning of the soft floor according to an embodiment of the present disclosure. <FIG> is a flowchart illustrating a method for allowing the robot cleaner to omit cleaning of the soft floor according to an embodiment of the present disclosure. As illustrated in <FIG>, it is basically assumed that the robot cleaner <NUM> cleans and travels about the hard floor region.

Referring to <FIG>, the robot cleaner <NUM> may recognize and detect the floor state on the basis of the detection result of the sensing portion <NUM> (<NUM>).

When the floor state is the soft floor (Yes in <NUM>), the robot cleaner <NUM> may raise the suction force (<NUM>). That is, the robot cleaner <NUM> may be controlled to have the suction force corresponding to the soft floor.

Simultaneously, the robot cleaner <NUM> may perform priority cleaning about the soft floor region (<NUM>). For example, when the robot cleaner <NUM> moves from the soft floor region to the hard floor region, the controller <NUM> may recognize such movement toward the hard floor region, and may control the robot cleaner <NUM> to re-enter the soft floor region, such that the controller <NUM> may control the robot cleaner <NUM> to perform priority cleaning about the soft floor region by repeating the above movement detection and re-entry to the soft floor region.

When the priority cleaning of the soft floor region is completed (Yes in <NUM>), the controller <NUM> may again reduce the suction force (<NUM>), and may clean the remaining hard floor region from among the entire cleaning region R (<NUM>).

Referring to <FIG>, the controller <NUM> may recognize and detect the floor state (<NUM>), and may clean the entire cleaning region R (<NUM>). The controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the hard floor in the entire cleaning region R. When the robot cleaner <NUM> cleans the hard floor region while simultaneously traveling about the entire cleaning region R, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the hard floor. When the robot cleaner <NUM> cleans the soft floor region while simultaneously traveling about the entire cleaning region R, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the soft floor.

During the cleaning traveling mode of the robot cleaner <NUM>, the image sensor <NUM> may acquire an image regarding the cleaning region, and may store a cleaning map generated based on the acquired image in the storage portion <NUM> (<NUM>). The cleaning map may include information regarding the floor state of the cleaning region R.

If the robot cleaner <NUM> finishes cleaning and traveling about the entire cleaning region R, the robot cleaner <NUM> may perform repeated cleaning about the region corresponding to the soft floor (<NUM>). In more detail, the controller <NUM> may control the traveling portion <NUM> such that the robot cleaner <NUM> may re-enter the soft floor region. When the robot cleaner <NUM> enters the soft floor region, the controller <NUM> may control the suction module <NUM> to generate the suction force corresponding to the soft floor.

Referring to <FIG>, the robot cleaner <NUM> may repeatedly clean the soft floor region in which the robot cleaner <NUM> has difficulty in suctioning dust or foreign substances, resulting in increased cleaning efficiency.

When the floor state is the soft floor (Yes in <NUM>), the robot cleaner <NUM> may perform omitted cleaning in which the soft floor region is omitted from the entire cleaning region and thus the robot cleaner <NUM> cleans only the remaining region other than the soft floor region (<NUM>). That is, the robot cleaner <NUM> may clean only the hard floor region.

For example, when the robot cleaner <NUM> enters the soft floor region by crossing the border B between the hard floor region and the soft floor region while cleaning and traveling about the hard floor region, the controller <NUM> may determine that the floor state is changed from the hard floor to the soft floor.

In this case, the controller <NUM> may rotate the robot cleaner <NUM> by <NUM>°, such that the robot cleaner <NUM> may re-enter the hard floor region. In more detail, the controller <NUM> may control the traveling direction of the robot cleaner <NUM> by transmitting a control signal to the traveling portion <NUM>.

Referring to <FIG>, the robot cleaner <NUM> may quickly clean only the hard floor region using low suction force without cleaning the soft floor region, and may guide the user to manually clean the soft floor region, such that the battery lifetime of the robot cleaner <NUM> may increase and the robot cleaner <NUM> may perform efficient cleaning. <FIG> is a flowchart illustrating a method for allowing the robot cleaner to perform the cleaning traveling operation while simultaneously tracing a wall surface according to an embodiment of the present disclosure.

Referring to <FIG>, the robot cleaner <NUM> may recognize and detect the floor state on the basis of the detection result of the sensing portion <NUM> (<NUM>). When the floor state is the soft floor (Yes in <NUM>) and the robot cleaner <NUM> performs cleaning while simultaneously tracing the wall surface (Yes in <NUM>), the robot cleaner <NUM> may control the suction module <NUM> to have the third-level suction force (<NUM>).

Alternatively, when the floor state is the soft floor (Yes in <NUM>) and the robot cleaner <NUM> does not trace the wall surface (No in <NUM>), the robot cleaner <NUM> may control the suction module <NUM> to have the second-level suction force (<NUM>). In this case, the third-level suction force may be higher than the second-level suction force.

<FIG> is a flowchart illustrating a method for allowing the robot cleaner to recognize the floor state according to an embodiment of the present disclosure.

Referring to <FIG>, the robot cleaner <NUM> may detect load applied to the traveling wheel <NUM> (361a), and may detect load applied to the brush 131b (361b). The load applied to the traveling wheel <NUM> may be detected by the wheel sensor <NUM>, and the load applied to the brush 131b may be detected by the current sensor <NUM> configured to measure the current of the brush motor 131a.

The robot cleaner <NUM> may detect the floor state on the basis of the load applied to the traveling wheel <NUM> (362a), and may detect the floor state on the basis of the load applied to the brush 131b (362b).

The operation for detecting the floor state on the basis of the load applied to the traveling wheel <NUM> may include detecting the floor state on the basis of rpm information of the wheel motor and the duty ratio of the wheel motor. A detailed description thereof is identical to those of the robot cleaner <NUM> disclosed in the above-mentioned embodiments, and as such a detailed description thereof will herein be omitted for convenience of description.

The operation for detecting the floor state on the basis of the load applied to the brush 131b may include determining whether the current of the brush motor 131a is equal to or higher than a predetermined reference value.

When at least one of two decision results indicates the soft floor (Yes in <NUM>), the robot cleaner <NUM> may finally determine the floor state to be the soft floor (<NUM>), and may thus perform optimum control appropriate for the soft floor. The robot cleaner <NUM> may perform cleaning using different suction forces according to the floor states, may control the traveling route in different ways according to the floor states, and may visually or audibly inform the user of the detection result of the floor state. In addition, when the floor state is the soft floor, the robot cleaner <NUM> may control the blade <NUM> to move down, resulting in increased suction efficiency of dust or foreign substances.

Claim 1:
A cleaner comprising:
a main body (<NUM>),
a brush module (<NUM>) disposed at a lower part of the main body (<NUM>), comprising:
a brush (131b) configured to scatter foreign substances on a floor, and
a brush motor (131a) configured to rotate the brush;
a suction fan (132b) configured to suction the foreign substances;
a sensor (<NUM>) configured to detect, at predetermined time intervals, a load applied to the brush (131b), wherein the load applied to the brush (131b) varies based on a type of the floor;
a blade (<NUM>) configured to direct foreign substances scattered by the brush into a dust box (<NUM>) formed in the main body (<NUM>), and
a controller (<NUM>) configured to increase the suction force of the suction fan (132b) and move the blade (<NUM>) downwards in response to the load increasing as a result of the cleaner entering a soft floor from a hard floor, and
decrease the suction force of the suction fan and move the blade upwards in response to the load decreasing as a result of the cleaner entering the hard floor from the soft floor.