Patent Publication Number: US-2022211237-A1

Title: Robot vacuum cleaner and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a by-pass continuation application of International PCT Application No. PCT/KR2020/008932 filed on Jul. 8, 2020, which is based on and claims priority to Korean Patent Application No. 10-2019-0118274 filed on Sep. 25, 2019 in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     1. Field 
     The disclosure relates to a robot vacuum cleaner and a control method thereof, more particularly to a robot vacuum cleaner that enters a return mode and removes dust around the robot vacuum cleaner by performing a dust removal operation immediately before coming into contact with a charging station and a control method thereof. 
     2. Description of Related Art 
     A robot vacuum cleaner is a device that cleans a certain area on its own without a user&#39;s manipulation. A charging station is a device for charging the robot vacuum cleaner and may be fixedly disposed at a predetermined location. 
     In the related art, there is a problem in that when the robot vacuum cleaner returns to the charging station, dust is accumulated near the charging station as the robot vacuum cleaner drags the collected dust when returning to the charging station. 
     There have been methods for removing dust from the charging station, but there is a limitation in removing the dust for the charging station having a fixed location, and there is a problem in that a manufacturing cost of the charging station is increased. 
     SUMMARY 
     Provided is a robot vacuum cleaner for removing dust around the robot vacuum cleaner before the robot vacuum cleaner returns to a charging station, and a control method thereof. 
     Additional aspects will be set forth in part in the description which follows, and in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     In accordance with an aspect of the disclosure, there is provided a robot vacuum cleaner including: a driver configured to move the robot vacuum cleaner; a memory storing information about a charging station of the robot vacuum cleaner; and a processor configured to: based on entering a return mode for returning to the charging station, control the driver to move the robot vacuum cleaner to the charging station based on the information about the charging station stored in the memory; perform a dust removal operation based on a distance between the robot vacuum cleaner and the charging station being less than or equal to a critical distance; and control the driver to move the robot vacuum cleaner such that the robot vacuum cleaner is in contact with the charging station after the dust removal operation. 
     The robot vacuum cleaner may further include a suction unit for collecting dust, and 
     the dust removal operation may include stopping an operation of the driver and operating the suction unit to remove dust around the suction unit. 
     The robot vacuum cleaner may further include a side brush, and the dust removal operation may include stopping an operation of the driver and operating the side brush to remove dust around the side brush. 
     The dust removal operation may further include stopping the operation of the suction unit and moving the robot vacuum cleaner in a first direction and a second direction to remove dust attached to the robot vacuum cleaner. 
     The processor is further configured to: control the driver to move the robot vacuum cleaner within a predetermined distance radius from a current location of the robot vacuum cleaner, based on the distance between the robot vacuum cleaner and the charging station being less than or equal to the critical distance; and perform the dust removal operation while moving within the predetermined distance radius. 
     The robot vacuum cleaner further includes: a battery for supplying power of the robot vacuum cleaner, wherein the processor is further configured to control the robot vacuum cleaner to enter the return mode based on a remaining capacity of the battery becoming a predetermined value. 
     The robot vacuum cleaner further includes: a communicator, wherein the processor is further configured to control the communicator to receive a command with respect to the return mode from the charging station. 
     The memory stores map information about a cleaning area, wherein the processor is configured to acquire information about a distance to the charging station based on the map information. 
     The robot vacuum cleaner further includes: a distance sensor configured to measure a distance to the charging station, wherein the processor is further configured to acquire information about the distance to the charging station through the distance sensor. 
     The processor is further configured to: perform a cleaning operation around the charging station after the dust removal operation, and control the driver to come into contact with the charging station after the cleaning operation. 
     In accordance with an aspect of the disclosure, there is provided a method of controlling a robot vacuum cleaner including: based on entering a return mode for returning to a charging station, moving the robot vacuum cleaner to the charging station; based on a distance between the robot vacuum cleaner and the charging station being less than or equal to a critical distance, performing a dust removal operation; and controlling the robot vacuum cleaner to be in contact with the charging station after the dust removal operation. 
     The dust removal operation may include stopping a movement of the robot vacuum cleaner and operating a suction unit of the robot vacuum cleaner to remove dust around the suction unit. 
     The dust removal operation may include stopping a movement of the robot vacuum cleaner and operating a side brush of the robot vacuum cleaner to remove dust around the side brush. 
     The dust removal operation may further include stopping the operation of the suction unit and moving the robot vacuum cleaner in a first direction and a second direction to remove dust attached to the robot vacuum cleaner. 
     The performing the dust removal operation includes: based on the distance between the robot vacuum cleaner and the charging station being less than or equal to the critical distance, moving the robot vacuum cleaner within a predetermined distance radius from a current location of the robot vacuum cleaner; and performing the dust removal operation while moving within the predetermined distance radius. 
     According to one or more embodiments of the disclosure, a robot vacuum cleaner may prevent dust from accumulating in the charging station by performing a dust removal operation around the robot vacuum cleaner before the robot vacuum cleaner returns to the charging station. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view illustrating a robot vacuum cleaner and a charging station according to an embodiment; 
         FIG. 2  is a view illustrating a movement of a robot vacuum cleaner according to an embodiment; 
         FIG. 3  is a view illustrating a method of performing a dust removal operation by a robot vacuum cleaner moving within a predetermined distance radius according to an embodiment; 
         FIG. 4  is a flowchart illustrating a method of controlling a robot vacuum cleaner according to an embodiment; 
         FIG. 5  is a flowchart illustrating a detailed control method of a robot vacuum cleaner according to an embodiment; and 
         FIG. 6  is a block diagram illustrating a robot vacuum cleaner according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the disclosure will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a view illustrating a robot vacuum cleaner and a charging station according to an embodiment. 
     The robot vacuum cleaner  100  refers to an electronic device for automatically drawing or collecting foreign substances or particles by means of suction. In  FIG. 1 , it is assumed that the robot vacuum cleaner  100  is implemented in a flat shape in close contact with a floor to collect foreign substances or particles on the floor, but this is only an example, and the robot vacuum cleaner  100  may be implemented in various shapes and sizes. 
     The robot vacuum cleaner  100  and the charging station  200  may be installed inside a house, and the robot vacuum cleaner  100  may collect foreign substances and particles while moving according to a predetermined pattern or a command received from the user and remove dust from the floor. In order to clean dust, the robot vacuum cleaner  100  may include a driver including a driving motor for rotating the wheels installed on the robot vacuum cleaner  100 . For example, one or more wheels can be disposed on the left and right sides of the robot vacuum cleaner  100  to move the robot vacuum cleaner  100 . 
     In addition, the robot vacuum cleaner  100  may include a cleaning device for sucking and collecting dust. The cleaning device may include a suction unit including a suction motor for sucking dust and a side brush for collecting dust. 
     The charging station  200  is configured to charge the robot vacuum cleaner  100 . When the robot vacuum cleaner  100  is in a return mode for returning to the charging station  200 , the robot vacuum cleaner  100  may stop cleaning and move to the charging station  200 . Specifically, since the robot vacuum cleaner  100  performs operations such as movement and suction during its cleaning operation, a battery of a certain capacity or more is required for the cleaning operation. Accordingly, when the battery of the robot vacuum cleaner  100  is consumed and the remaining capacity of the battery becomes a predetermined value, the robot vacuum cleaner  100  may go into the return mode for charging the battery and move to the charging station  200 . The predetermined value may be preset by its manufacturer and/or may be input by the user. When the remaining capacity of the battery is a predetermined value, the robot vacuum cleaner may go into the return mode, but is not limited thereto, and the robot vacuum cleaner  100  may go into the return mode due to a user input or the robot vacuum cleaner  100  may go into the return mode when the cleaning operation is completed. Also, the robot vacuum cleaner  100  may receive a command with respect to the return mode from the charging station  200  and go into the return mode. 
     According to an embodiment of the disclosure, the robot vacuum cleaner  100  may perform a dust removal operation when a distance to the charging station  200  is less than or equal to a critical distance while moving to the charging station  200 . In other words, when the distance to the charging station  200  exceeds the critical distance while the robot vacuum cleaner  100  moves to the charging station  200 , the robot vacuum cleaner  100  may move to the charging station  200  in a state that the suction unit and the side brush of the robot vacuum cleaner  100  do not operate. In addition, the robot vacuum cleaner  100  may perform a dust removal operation when the distance to the charging station  200  is less than or equal to the critical distance while moving to the charging station  200 . 
     The critical distance may be predetermined by the manufacturer and/or may be input by the user. 
     According to an embodiment, the robot vacuum cleaner  100  may include a distance sensor that receives a signal transmitted by the charging station to acquire distance information from the charging station  200 . The distance sensor is configured to measure a distance from the charging station  200 , and when the distance sensor receives a signal transmitted from the charging station  200 , the robot vacuum cleaner  100  may acquire information on a distance to the charging station  200  based on the received signal. The distance sensor may include an infrared sensor, an ultrasonic sensor, a radio frequency (RF) sensor, or the like, and may be provided on one side of an inside or outside of the robot vacuum cleaner  100 . 
     Although it has been described that the distance information between the robot vacuum cleaner  100  and the charging station  200  is acquired using the signal received by the distance sensor, the robot vacuum cleaner  100  may be moved to the charging station by using location information of the charging station stored in a memory of the robot vacuum cleaner  100 . In other words, map information on a cleaning area may be stored in the memory of the robot vacuum cleaner  100 , and the robot vacuum cleaner  100  may acquire distance information from the charging station  200  based on the map information. 
     The dust removal operation is an operation of removing dust around the robot vacuum cleaner  100 , and the robot vacuum cleaner  100  removes dust around the charging station  200 , before the robot vacuum cleaner  100  comes into contact with the charging station  200 , to prevent dust from accumulating. 
     The dust removal operation according to an embodiment of the disclosure may include a first dust removal operation in which the suction unit is operated while the robot vacuum cleaner  100  is stopped, to remove dust around the suction unit, and a second dust removal operation in which the side brush is operated while the robot vacuum cleaner  100  is stopped to remove dust around the side brush. In other words, unlike a cleaning operation in which the suction unit and the side brush are operated while the robot vacuum cleaner  100  moves, the robot vacuum cleaner  100  may remove dust around the robot vacuum cleaner  100  before coming into contact with the charging state  200  through the first dust removal operation and the second dust removal operation. 
     In addition, the dust removal operation may include a third dust removal operation of moving the robot vacuum cleaner  100  in a first direction and moving the robot vacuum cleaner  100  in a second direction. Through the third dust removal operation, the robot vacuum cleaner  100  may come into contact with the charging station  200  after the robot cleaner  100  drops the dust attached to the robot cleaner  100  on the floor. The first direction may be a direction different from a direction in which the robot vacuum cleaner  100  goes into the return mode and moves to the charging station  200 , and the second direction may be a different direction from the first direction. According to an embodiment, the second direction may be opposite to the first direction. 
     According to an embodiment of the disclosure, the dust removal operation may be an operation of performing at least one of the first to third operations described above. Also, the disclosure is not limited thereto, and at least one of the first to third operations may be performed together. For example, after the third operation of making the dust attached to the robot vacuum cleaner fall on the floor is performed, the dust around the robot vacuum cleaner may be removed by performing the first dust removal operation and the second dust removal operation. However, the dust removal operation described above is not limited to the first to third operations, and may be an operation in which the suction unit and the side brush are operated like a cleaning operation while the robot vacuum cleaner  100  moves. 
     In addition, when a distance to the charging station  200  is less than or equal to the critical distance, the robot vacuum cleaner  100  may perform the dust removal operation while moving within a predetermined distance radius from a current location. A method for the robot vacuum cleaner  100  to perform the dust removal operation while moving within the predetermined distance radius will be described below with reference to  FIG. 3 . 
     When the dust removal operation is completed, the robot vacuum cleaner  100  may come into contact the charging station  200  to charge its battery. However, the disclosure is not limited thereto, and when the dust removal operation is completed, the robot vacuum cleaner  100  may perform a cleaning operation around the charging station  200  and come into contact with the charging station  200 . The robot vacuum cleaner  100  may come into contact with the charging station  200  such that the robot vacuum cleaner  100  and the charging station  200  may be physically connected and the battery of the robot vacuum cleaner  100  may be charged, but is not limited thereto. When the robot vacuum cleaner  100  approaches the charging station  200 , the battery of the robot vacuum cleaner  100  may be charged using a wireless charging method. 
     Through the process described above, the dust removal operation with respect to the robot vacuum cleaner  100  and around the robot vacuum cleaner  100  may be performed, thereby preventing dust from accumulating in the charging station. 
       FIG. 2  is a view illustrating a movement of a robot vacuum cleaner according to an embodiment. 
     Referring to  FIG. 2 , when the robot vacuum cleaner  100  goes into return mode while performing a cleaning operation, it may move to the charging station  200 . Specifically, the robot vacuum cleaner  100  may move to the charging station based on information about the charging station  200  stored in the memory. In other words, map information on a cleaning area may be stored in the memory of the robot vacuum cleaner  100 , and the robot vacuum cleaner  100  may acquire information on the charging station  200  based on the map information. However, the disclosure is not limited thereto, and when the robot vacuum cleaner  100  includes a distance sensor, the robot vacuum cleaner  100  may acquire distance information from the charging station  200  through the distance sensor and move to the charging station  200 . Alternatively or additionally, the robot vacuum cleaner  100  may use the map information and the distance information to control movement of the robot vacuum cleaner  100 . 
     While the robot vacuum cleaner  100  is moving to the charging station  200 , if a distance between the robot vacuum cleaner  100  and the charging station  200  is less than or equal to a critical distance (a), the robot vacuum cleaner  100  may perform a dust removal operation. Specifically, when the distance from the charging station  200  is less than or equal to the critical distance a, the robot vacuum cleaner  100  may stop moving and operate a suction unit or operate a side brush to perform dust removal. In addition, the robot vacuum cleaner  100  may stop the operation of the suction unit and the side brush, move in a second direction after moving in a first direction, and perform the dust removal operation. 
     The critical distance a between the robot vacuum cleaner  100  and the charging station  200  may be predetermined by a manufacturer and/or may be input by the user. 
     In an embodiment according to the disclosure, when map information with respect to a cleaning area is stored in the memory of the robot vacuum cleaner  100 , the robot vacuum cleaner  100  may acquire distance information from the charging station based on the map information, and may identify, based on the acquired distance information, whether the distance to the charging station  200  is equal to or less than the critical distance a. The map information on the cleaning area may include an area to be cleaned by the robot vacuum cleaner  100  and location information of the charging station  200  in a shape of a space to be cleaned. According to an embodiment, when there is no map information in the memory of the robot vacuum cleaner  100 , the robot vacuum cleaner  100  may move according to a predetermined algorithm, and may generate map information according to a movement trajectory of the robot vacuum cleaner  100 . Also, distance information between the robot vacuum cleaner  100  and the charging station  200  may be acquired by storing the generated map information in the memory as in the method described above. 
     In an embodiment according to the disclosure, when the robot vacuum cleaner  100  further includes a distance sensor for measuring the distance to the charging station  200 , the robot vacuum cleaner  100  may acquire distance information to the charging station  200  through the distance sensor. Specifically, the distance sensor may receive a signal transmitted from the charging station  200 , and the robot vacuum cleaner  100  may acquire distance information between the robot vacuum cleaner  100  and the charging station  200  based on a strength of the received signal. Based on the acquired distance information, the robot vacuum cleaner  100  may identify whether the distance to the charging station  200  is equal to or less than the critical distance a. 
       FIG. 3  is a view illustrating a method of performing a dust removal operation by a robot vacuum cleaner moving within a predetermined distance radius according to an embodiment. 
     When the distance to the charging station  200  is less than or equal to the critical distance, the robot vacuum cleaner  100  may control a driver of the robot vacuum cleaner  100  to move within a predetermined distance radius from a current location of the robot vacuum cleaner  100 . In addition, the robot vacuum cleaner  100  may perform a dust removal operation on the robot vacuum cleaner  100  while moving within the predetermined distance radius. The predetermined distance may be predetermined by the manufacturer and/or may be input by the user. 
     Referring to  FIG. 3 , the robot vacuum cleaner  100  may perform a dust removal operation while moving within a radius area of a predetermined distance b from the robot vacuum cleaner  100 . Specifically, the robot vacuum cleaner  100  may operate a side brush or operate a suction unit to perform the dust removal operation with respect to the robot vacuum cleaner  100  while moving within the predetermined distance radius b. Also, the robot vacuum cleaner  100  may perform first to third dust removal operations described above with reference to  FIG. 1  while moving within the predetermined distance radius b. For example, the robot vacuum cleaner  100  may stop for a predetermined time and perform a first dust removal operation that drives the suction unit, while moving within the predetermined distance radius b, and move within the predetermined distance radius b again and stop for a while to operate a second dust removal operation that drives the side brush, and move within the predetermined distance radius b again. 
     As described above, while the robot vacuum cleaner  100  moves within a predetermined distance radius, the robot vacuum cleaner  100  may remove dust from the robot vacuum cleaner  100  and dust around the robot vacuum cleaner  100  by performing a dust removal operation with respect to the robot vacuum cleaner  100 , and return to the charging station  200 . 
       FIG. 4  is a flowchart illustrating a method of controlling a robot vacuum cleaner according to an embodiment. 
     Referring to  FIG. 4 , when the robot vacuum cleaner  100  goes into the return mode, the robot vacuum cleaner  100  may move to the charging station  200  (S 410 ). When a battery of the robot vacuum cleaner  100  is consumed and a remaining capacity of the battery becomes a predetermined value, the robot vacuum cleaner  100  may go into the return mode. However, the disclosure is not limited thereto, and the robot vacuum cleaner  100  may go into the return mode according to a user&#39;s input, and when the cleaning operation is completed, the robot vacuum cleaner  100  may go into the return mode. In addition, the robot vacuum cleaner  100  may go into the return mode by receiving a command for the return mode from the charging station  200 . 
     While the robot vacuum cleaner  100  in the return mode and moving toward the charging station  200 , when a distance between the charging station  200  and the robot vacuum cleaner  100  becomes less than or equal to a critical distance, the robot vacuum cleaner  100  may perform the dust removal operation (S 420 ). The critical distance may be predetermined by the manufacturer and/or may be input by the user. 
     The dust removal operation is an operation of removing dust from the robot vacuum cleaner and dust around the robot vacuum cleaner  100 , and include a first dust removal operation that removes dust around the suction unit by an operation of the suction unit while the robot vacuum cleaner  100  stops, a second dust removal operation that removes dust around the side brush by an operation of the side brush while the robot vacuum cleaner  100  stops, and a third dust removal operation that moves the robot vacuum cleaner in a second direction after moving the robot vacuum cleaner in a first direction and drops or detaches dust attached to the robot vacuum cleaner  100  on the floor. 
     When the dust removal operation is completed, the robot vacuum cleaner  100  may come into contact with the charging station  200  (S 430 ). In other words, when the dust removal operation is completed, the robot vacuum cleaner  100  may return to the charging station  200  and charge the battery of the robot vacuum cleaner  100 . 
       FIG. 5  is a flowchart illustrating a detailed control method of a robot vacuum cleaner according to an embodiment. 
     Referring to  FIG. 5 , the robot vacuum cleaner  100  may perform a cleaning operation (S 510 ). When a remaining battery capacity of the robot vacuum cleaner  100  is less than or equal to a predetermined value (S 520 -Y), the robot vacuum cleaner  100  may move to the charging station  200  (S 530 ). Here, the robot vacuum cleaner  100  may move to the charging station while or after performing the cleaning (S 510 ). When the remaining battery capacity of the robot vacuum cleaner  100  exceeds the predetermined value (S 520 -N), the robot vacuum cleaner  100  may continue cleaning (S 510 ). 
     In addition, when the distance between the robot vacuum cleaner  100  and the charging station  200  are less than a critical distance (S 540 -Y), the robot vacuum cleaner  100  may perform a dust removal operation (S 550 ). The dust removal operation is an operation of removing dust from the robot vacuum cleaner  100  and dust around the robot vacuum cleaner  100 . When the distance between the robot vacuum cleaner  100  and the charging station  200  exceeds the critical distance (S 540 -N), the robot vacuum cleaner  100  may continue to move to the charging station  200  (S 530 ). In other words, when the distance to the charging station  200  exceeds the critical distance while the robot vacuum cleaner  100  moves to the charging station  200 , the robot vacuum cleaner  100  may move to the charging station  200  in a state that the suction unit and the side brush of the robot vacuum cleaner  100  do not operate. Alternatively, when the distance to the charging station  200  exceeds the critical distance, the suction unit and the side brush of the robot vacuum cleaner  100  may continue to operate while moving to the charging station  200 . 
     In addition, when the robot vacuum cleaner  100  completes the dust removal operation, the robot vacuum cleaner  100  may perform a cleaning operation around the charging station  200  (S 560 ). For example, the robot vacuum cleaner  100  may detect an area around the charging station  200  based on map information about a cleaning area stored in the memory, and perform a cleaning operation on the detected surrounding area. A cleaning operation may be a task in which the robot vacuum cleaner  100  moves around the charging station  200  and the side brush and the suction unit of the robot vacuum cleaner  100  are operated. In another embodiment, the robot vacuum cleaner  100  may further include a distance sensor for measuring a distance to the charging station  200 , and the robot vacuum cleaner  100  may detect an area around the charging station  200  through the distance sensor and perform a cleaning operation on the surrounding area of the charging station  200 . 
     When the cleaning operation around the charging station  200  is completed, the robot vacuum cleaner  100  may come into contact with the charging station  200  (S 570 ), and the battery of the robot vacuum cleaner  100  may be charged. 
       FIG. 6  is a block diagram illustrating a robot vacuum cleaner according to an embodiment. 
     Referring to  FIG. 6 , the robot vacuum cleaner  600  may include a driver  610 , a memory  620 , a processor  630 , a suction unit  640 , a side brush  650 , a battery  660 , a communicator  670 , and a distance sensor  680 . 
     The driver  610  may include wheels on the left and right sides of a main body of the robot vacuum cleaner  600  and a driving motor for rotating and driving the wheels. Alternatively or additionally the driver  610  may independently rotate each driving motor of a plurality of driving motors in a forward or reverse direction according to a control signal of the processor  630 . Accordingly, a rotation angle or a traveling direction of the robot vacuum cleaner  600  may be determined by differently controlling a rotational frequency of each driving motor. 
     The memory  620  may store map information about a place for the robot vacuum cleaner  600  to perform a task, such as a cleaning operation, and information about a charging station. The map information may be an image file such as a floor plan of an indoor space. However, the disclosure is not limited thereto, and various programs necessary for operating the robot vacuum cleaner  600  may be stored in the memory  620 . 
     The memory  620  may store a plurality of application programs (application program or application) executed by the processor  630  of the robot vacuum cleaner  600 , data and commands for operation of the robot vacuum cleaner  600 . At least some of these application programs may be downloaded from an external server through wireless communication. In addition, at least some of these application programs may exist, from the time of release, on the robot vacuum cleaner  600  for a basic function of the robot vacuum cleaner  600 . The application program may be stored in the memory  620 , and may be executed by the processor  630  to perform the operation of the robot vacuum cleaner  600 . 
     The memory  620  may be implemented as a non-volatile memory, a volatile memory, a flash memory, a hard disk drive (HDD) or a solid state drive (SDD). The memory  620  may be accessed by the processor  630 , and perform readout, recording, correction, deletion, update, or the like, on data by the processor  630 . According to an exemplary embodiment, the term “memory” as used herein may include a memory  620 , a read-only memory (ROM), and a random access memory (RAM) within the processor  630 , or a memory card mounted on the electronic device  600  (e.g., micro SD card, memory stick). 
     The processor  630  may, for example, control a number of hardware or software elements connected to the processor  630  by driving an operating system or application program, and perform various data processing and calculations. Further, the processor  630  may load and process a command or data received from at least one of the other components to a volatile memory and store diverse data in a non-volatile memory. 
     For this operation, the processor  630  may be realized a dedicated processor for performing functions (for example, embedded processor) or a generic-purpose processor for performing functions by running one or more software programs stored in a memory device (for example, a CPU or an application processor). 
     The processor  630  may perform a cleaning operation according to a user command. In addition, when going into the return mode during the cleaning operation, the processor may control the driver  610  to move to the charging station. Specifically, the processor  630  may control the driver  610  to move to the charging station based on information on the charging station stored in the memory  620 . As an embodiment, the information on the charging station may be acquired based on map information on the cleaning area stored in the memory  620 . However, the disclosure is not limited thereto, and the driver  610  may be controlled to move the robot vacuum cleaner  600  to the charging station while receiving a signal transmitted from the charging station through the distance sensor  680  of the robot vacuum cleaner  600 . 
     When the robot vacuum cleaner  600  goes into the return mode, the processor  630  may control the driver  610  to move the robot vacuum cleaner  600  to the charging station. 
     When a battery of the robot vacuum cleaner  600  is consumed and a remaining capacity of the battery becomes a predetermined value, the robot vacuum cleaner  600  may go into the return mode for charging the battery, and the processor  630  may control the driver  610  to move the robot vacuum cleaner  600  to the charging station. A predetermined value may be predetermined by the manufacturer and/or may be input by the user. The robot vacuum cleaner  600  may go into the return mode when the remaining capacity of the battery is a predetermined value, but is not limited thereto. The robot vacuum cleaner  600  may go into the return mode according to a user input or the robot vacuum cleaner  600  may go into the return mode when the cleaning operation is completed. In addition, the processor  630  may control the communicator  670  to receive a command for the return mode from the charging station, such that the robot vacuum cleaner  600  may go into the return mode. 
     In addition, in the return mode, when a distance between the robot vacuum cleaner  600  and the charging station is less than or equal to a critical distance, the processor  630  may control the suction unit  640  and the side brush  650  to perform a dust removal operation with respect to the robot vacuum cleaner. When the distance to the charging station exceeds the critical distance while the robot vacuum cleaner  600  moves to the charging station, the processor  630  may control the driver  610  to move to the charging station without operating the suction unit  640  and the side brush  650 . Alternatively or additionally, when the distance to the charging station exceeds the critical distance while the vacuum cleaner  600  moves to the charging station, the processor  630  may control the driver  610  to move to the charging station while the suction unit  640  and the side brush  650  are operating. The critical distance may be predetermined by the manufacturer and/or may be input by the user. Specifically, when the robot vacuum cleaner  600  goes into the return mode, the processor  630  may identify whether the robot vacuum cleaner  600  is less than the critical distance from the charging station based on the distance information between the robot vacuum cleaner  600  and the charging station. 
     As an example, the processor  630  may use the distance sensor  680  that receives a signal transmitted by the charging station to acquire distance information between the robot vacuum cleaner  600  and the charging station. Also, the processor  630  may control the driver  610  to move the robot vacuum cleaner  600  to the charging station by using location information of the charging station. In other words, map information on the cleaning area is stored in the memory  620  of the robot vacuum cleaner  600 , and the robot vacuum cleaner  600  may acquire distance information from the charging station based on the map information. 
     The dust removal operation is an operation of removing dust around the robot vacuum cleaner  600 , and immediately before the robot vacuum cleaner  100  comes into contact with the charging station  200 , the robot vacuum cleaner  100  removes dust around the charging station  200  to prevent dust from accumulating. 
     The dust removal operation according to an embodiment of the disclosure may include a first dust removal operation that the processor controls the suction unit  640  to be operated in a state in which the processor  630  controls the driver to stop an operation and the robot cleaner  600  is stopped such that dust around the suction unit  640  is removed, a second dust removal operation that the processor  630  controls the side brush  650  to be operated in a state that the robot vacuum cleaner  600  is stopped such that dust around the side brush  650  is removed, and a third dust removal operation that the processor  630  controls the suction unit  640  to stop the operation, and controls the driver  610  to move the robot vacuum cleaner  600  in a first direction and in a second direction such that dust around the robot vacuum cleaner  600  falls on the floor. The first direction may be a direction different from a direction in which the robot cleaner  600  moves to the charging station, and the second direction may be a direction different from the first direction. According to an embodiment, the second direction may be an opposite direction to the first direction. 
     In addition, the processor  630  may control the driver  610  to move within a predetermined distance radius from a current location of the robot vacuum cleaner  600  when a distance between the robot vacuum cleaner  600  and the charging station is less than or equal to a critical distance, and the processor  630  may perform a dust removal operation while the robot vacuum cleaner  600  moves within the predetermined distance radius. 
     In addition, when the dust removal operation is completed, the processor  630  may control the driver  610  to bring the robot vacuum cleaner  600  into contact with the charging station. Alternatively, when the dust removal operation is completed, the processor  630  may perform a cleaning operation on the charging station, and when the cleaning operation is completed, the robot vacuum cleaner  600  may control the driver  610  to come into contact with the charging station. 
     The suction unit  640  may suck dust on a bottom surface of the robot vacuum cleaner  600 . Specifically, the suction unit  640  may perform a cleaning operation by absorbing dust located in a lower part of the robot vacuum cleaner  600  while moving or stopped. In an embodiment, the suction unit  640  may further include an air purification unit for purifying pollutants in the air. 
     In addition, the suction unit  640  may have a plurality of operation modes. The plurality of operation modes may be divided according to suction strength, and may be predetermined by the user or may be changed according to the weather. For example, the operation mode may be divided into 1 to 5 according to suction strength, and when a value predetermined by the user is 3, the suction unit  640  may be operated in an operating mode of 4 or 5 higher than a value predetermined by the user, when there is a yellow dust or fine dust warning. 
     The side brush  650  may be disposed on a lower side of front sides of the robot vacuum cleaner  600  and may be configured to collect dust or the like into the suction unit  640 . Specifically, the side brush  650  may include a rotating brush rotating in a horizontal plane with respect to the floor and a side brush motor for rotating the rotating brush. According to an embodiment of the disclosure, the processor  630  may perform a dust removal operation by controlling the side brush  650  to operate in a state where the robot vacuum cleaner  600  is stopped. 
     The battery  660  is configured to supply power to the robot vacuum cleaner  600 , and the battery  660  of the robot vacuum cleaner  600  may be charged by the charging station. A charging method of the battery may be a constant current constant voltage (CCCV) charging method in which a predetermined capacity is rapidly charged through a constant current (CC) charging method and the remaining capacity is charged through a constant voltage (CV) method, but is not limited thereto. According to an embodiment of the disclosure, the robot vacuum cleaner  600  may go into the return mode when the remaining capacity of the battery  660  becomes a predetermined value. 
     The communicator  670  may be communication circuitry that is configured to connect the robot vacuum cleaner  600  to an external device (e.g., a charging station, a terminal device, an external server, or the like). For example, the communicator  670  may use any of various wireless communication methods, such as NFC, a wireless LAN, IR communication, ZigBee communication, Wi-Fi, Bluetooth, or the like. Additionally, the communicator  670  may communicate with an external device in a wired manner (e.g., Ethernet, etc.). 
     Further, the communicator  670  may receive access point information from an external device. For example, the communicator  670  may receive global map information including location information about a space or a location where the robot vacuum cleaner  600  is to operate, from the external device. The communicator  670  may also transmit and receive information for updating the global map information to the external device. 
     In addition, the communicator  670  may receive a cleaning command. The cleaning command may be a cleaning command for an entire space or a cleaning command for a specific space. 
     In addition, the communicator  670  may receive a return command. Specifically, when a return command is received from the user&#39;s terminal device or when a remaining capacity of the battery of the robot vacuum cleaner  600  becomes a predetermined value, the communicator may receive a command for the return mode from the charging station. 
     The distance sensor  680  is configured to receive a signal transmitted by the charging station to acquire distance information between the robot vacuum cleaner and the charging station. Specifically, when the distance sensor  680  receives a signal transmitted from the charging station, the processor  630  may acquire distance information from the charging station based on a magnitude of the received signal. 
     In addition, the distance sensor may include an infrared ray sensor, an ultra-sonic sensor, a radio frequency (RF) sensor, or the like, and may be provided on one side of the inside or outside of the robot vacuum cleaner  600 . 
     Terms used in the disclosure are selected as general terminologies currently widely used in consideration of configurations and functions of the one or more embodiments of the disclosure, but can be different depending on intention of those skilled in the art, a precedent, appearance of new technologies, or the like. Further, in specific cases, terms may be arbitrarily selected. In this case, the meaning of the terms will be described in the description of the corresponding embodiments. Accordingly, the terms used in the description should not necessarily be construed as simple names of the terms, but be defined based on meanings of the terms and overall context of the disclosure. 
     In the disclosure, the terms “include” and “comprise” designate the presence of features, numbers, steps, operations, components, elements, or a combination thereof that are written in the specification, but do not exclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, elements, or a combination thereof. 
     In the disclosure, the term “at least one of A or B” may designate (1) only A, (2) only B, or (3) both A and B. 
     The expression “first” or “second” as used herein may modify a variety of elements, irrespective of order and/or importance thereof, and only to distinguish one element from another. Accordingly, without limiting the corresponding elements. 
     When an element (e.g., a first element) is “operatively or communicatively coupled with/to” or “connected to” another element (e.g., a second element), an element may be directly coupled with another element or may be coupled through the other element (e.g., a third element). 
     Singular forms are intended to include plural forms unless the context clearly indicates otherwise. The terms “include”, “comprise”, “is configured to,” etc., of the description are used to indicate that there are features, numbers, steps, operations, elements, parts or combination thereof, and they should not exclude the possibilities of combination or addition of one or more features, numbers, steps, operations, elements, parts or a combination thereof. 
     In the disclosure, a ‘module’ or a ‘unit’ performs at least one function or operation and may be implemented by hardware or software or a combination of the hardware and the software. In addition, a plurality of ‘modules’ or a plurality of ‘units’ may be integrated into at least one module and may be at least one processor except for ‘modules’ or ‘units’ that should be realized in a specific hardware. 
     In the disclosure, the term “user” may refer to a person using a robot vacuum cleaner or a device (e.g., an artificial intelligence robot vacuum cleaner) using the robot vacuum cleaner.