KR101403954B1 - Control method of robot cleaner system - Google Patents

Abstract

The present invention relates to a control method of a robot cleaner system, and an object of the present invention is to provide a robot cleaner system control method, And to return to the area where the cleaning is interrupted and perform the cleaning again from that point, thereby minimizing the overlapping cleaning area and enabling the cleaning of the uncleaned area.

To this end, a method of controlling a robot cleaner system according to the present invention includes: performing a cleaning operation while the robot cleaner travels on a wall reference travel pattern; Stopping the cleaning operation and returning to the docking station for charging or discharging dust; Calculating a return distance using the position information of the robot cleaner before stopping the cleaning operation; And controlling to restart the cleaning operation after returning to the cleaning stop area using the return distance.

Robot cleaner, refer to the wall driving, return to the stop area

Description

[0001] The present invention relates to a robot cleaner system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a control method of a robot cleaner system, and more particularly, to a control method of a robot cleaner system that restarts cleaning after returning to a stopped area.

Generally, the robot cleaner is a device for automatically cleaning an area to be cleaned by suctioning foreign matter such as dust from a floor surface while traveling the area to be cleaned by itself without user's operation. The robot cleaner senses distances to obstacles such as furniture, office supplies, and walls installed in the cleaning area through an infrared sensor or the like, and cleans the cleaning area while traveling to avoid collision with obstacles using the sensed information.

Cleaning of a given cleaning area by using the robot cleaner means a process in which the robot cleaner travels in a preset driving pattern and repeatedly performs a cleaning operation. If the robot cleaner determines that it is necessary to charge the battery or discharge the collected dust while performing the cleaning operation as described above (it may be determined by the robot cleaner itself or may be ordered by the user), the robot cleaner may return to the docking station To perform charging or discharging operations.

At this time, in the case of a robot cleaner (that is, a robot cleaner not equipped with a vision system such as a position recognition camera) in which the position of the robot itself can not be accurately recognized during traveling, It is impossible to know the information (location information, distance information, and the like) of the area that has already been cleaned (before stopping the cleaning). Therefore, when the cleaning is resumed after charging or discharging the dust, the robot cleaner performs the cleaning work from the beginning again, so that the cleaning area (the pre-cleaning area) before the return to the docking station is re-cleaned or the non- There is a problem that a situation may occur.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a docking station which stops a cleaning operation due to insufficient battery, The cleaning area is returned to the area where the cleaning is stopped, and the cleaning is performed again from that point, thereby minimizing the overlapping cleaning area and enabling the cleaning of the uncleaned area.

According to another aspect of the present invention, there is provided a method of controlling a robot cleaner system, including: performing a cleaning operation while the robot cleaner travels on a wall reference travel pattern; Stopping the cleaning operation and returning to the docking station for charging or discharging dust; Calculating a return distance using the position information of the robot cleaner before stopping the cleaning operation; And controlling to restart the cleaning operation after returning to the cleaning stop area using the return distance.

In addition, the wall reference travel pattern repeats a series of processes of following the reference wall surface, leaving from the reference wall surface, moving by a certain distance, and returning to the reference wall surface.

Further, the position information of the robot cleaner is estimated by using a navigation method before stopping the cleaning operation.

Further, the return distance D is calculated by using the formula D = Σd _wall + Σd _gap (where d _wall is the wall follow-up distance, and d _gap is the distance between the traces following the wall).

Further, the robot cleaner follows the wall by the return distance and returns to the cleaning interruption area.

In addition, from the end point of the wall-following cruise, the user carries out the cleaning operation for the uncleaned area while traveling on the wall reference travel pattern.

According to the present invention, the robot cleaner returns to the docking station during the cleaning operation, performs charging or discharging dust, etc., and then returns to the area where the cleaning is stopped when the cleaning operation is resumed, So that the redundant cleaning area is minimized and the cleaning area can be cleaned.

Hereinafter, before describing the embodiment of the present invention in detail, the meaning of 'restoration of the stopped area of the cleaning' in the present invention will be briefly defined, and the preconditions for applying the present invention will be described.

First, in the present invention, the robot cleaner returns to the docking station in response to a judgment of the robot cleaner itself or a command from the user during the cleaning operation to stop the cleaning after completion of charging or discharging dust, etc. It is an algorithm to return to one area and resume cleaning.

In the present invention, it is possible to return to the cleaning interruption region even if the position error is accumulated according to the change of time and space in the process of estimating the current position during running of the robot cleaner. However, the present invention is applicable to a case where the robot cleaner adopts a traveling pattern (hereinafter referred to as a 'wall reference traveling pattern') that extends a cleaning area based on a wall surface.

The wall reference driving algorithm starts from the assumption that a typical residential space consists of a closed curve. As shown in FIG. 1, when the person starts walking from S to the left hand and continues to walk on the wall, he eventually returns to the starting point S, and if he draws this trajectory, he makes a boundary including all the interior spaces of the house (The left-hand method of wall-facing). When the robot cleaner cleans the inside of the locus indicated by a bold solid line in FIG. 1, the cleanable area can be cleaned thoroughly.

2 is a travel locus diagram (a cleaning order chart) of a robot cleaner to which an RWM (Reference Wall Based Matrix) algorithm is applied, which is an example of a wall reference travel pattern. RWM Algorithm follows the wall by distance d along the reference wall Driving → Reference Rotation in 90 ° direction with the wall → Advance by a certain distance L → Turn left by 90 ° → Advance by distance d → Turn left by 90 ° → Advance for return to the reference wall → It is a way to occupy the cleaning area by repeating the process of turning 90 degrees to follow the wall again (hereinafter referred to as 'process K').

2 (1), the cleaning area (living room) is filled in by repeating the process K with the reference wall surface as (A). In the cleaning process according to the RWM algorithm based on the wall- Next, as shown in (2) of FIG. 2, the reference wall surface is changed to (B), and the cleaning operation is continued in the same manner. In this case, a locus is formed in a direction perpendicular to the locus shown in Fig. 2 (1), resulting in a matrix-like running pattern. Thereafter, as shown in FIG. 2 (3), the reference wall surface is changed back to (C) to clean the room 1, and then the reference wall surface is changed to (D) as shown in (4) The cleaning operation is performed by drawing the locus of the matrix shape.

Such an RWM algorithm is based on a wall-following trajectory, and is a pattern that travels while filling the locus (refer to the thick solid line area in FIG. 1) formed through the wall-following pattern. Therefore, the RWM algorithm can clean the entire area to be cleaned .

In addition to the RWM algorithm shown in FIG. 2, the wall-mounted reference travel pattern of the robot cleaner to which the present invention can be applied basically carries out a cleaning operation along the wall surface and follows the wall surface even when moving in the cleaning area It is possible if it is a traveling pattern. The general pattern of running on the wall refers to following the reference wall → departing from the reference wall → moving by a certain distance → returning to the reference wall again, and the wall reference driving pattern varies depending on the situation as shown in FIG. .

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 4, the robot cleaner system according to an embodiment of the present invention includes a robot cleaner 100 and a docking station 200.

Here, the docking station 200 includes a transmitting unit 210 and a charging unit 220.

The transmitting unit 210 is installed near the receiving portion of the docking station 200 and transmits an infrared optical signal or an ultrasonic signal to recognize that the robot cleaner 100 has approached the charging station 200.

The charging unit 220 converts the commercial AC power input from the outside into electric power for charging the rechargeable battery 115 of the robot cleaner 100 so that the rechargeable battery 115 of the robot cleaner 100 can be charged.

The robot cleaner 100 further includes a receiving unit 105, an input unit 110, a remaining battery level detecting unit 120, an obstacle detecting unit 125, a travel distance detecting unit 130, a control unit 135, a driving unit 140, (145) and a storage unit (150).

The receiving unit 105 receives the infrared optical signal or the ultrasonic signal generated by the transmitting unit 210 of the docking station 200 and provides the receiving information to the controller 135.

The input unit 110 includes a plurality of keys on the upper portion of the robot cleaner main body or the remote controller so that the user can input a cleaning command (start / stop of operation) of the robot cleaner 100. [ In the present embodiment, after the return operation to the docking station 200 for charging (or discharging dust) the rechargeable battery 115 is started (selected) or the charge (or dust discharge) is completed in the input unit 110, (Or dust release) function key for performing the operation. That is, when the user operates the charging (or dusting) function key once, the robot cleaner 100 returns to the docking station 200 to charge the rechargeable battery 115 (or discharge the dust) Or dust discharge), the robot cleaner 100 returns to the area where the cleaning operation is interrupted before returning to the docking station 200, and the remaining cleaned (or dusted) The cleaning of the area is performed successively.

The battery remaining amount detection unit 120 detects the remaining charge amount of the rechargeable battery 115 and provides the remaining charge amount information to the control unit 135. [

The obstacle detecting unit 125 is for detecting obstacles such as furniture, office equipment, and walls installed in the cleaning area where the robot cleaner 100 travels. The obstacle sensing unit 125 transmits ultrasonic waves to a path traveled by the robot cleaner 100, An ultrasonic sensor for detecting the presence of an obstacle and a distance to an obstacle by receiving ultrasonic waves reflected by the ultrasonic wave impinging on the obstacle, or a plurality of infrared light emitting elements and a light receiving element for emitting infrared rays, An infrared sensor configured to receive infrared rays may be used.

The travel distance detecting unit 130 detects the distance traveled by the robot cleaner 100 and is provided at a lower portion of the robot cleaner 100 for driving the wheels 141 and 142 Is detected through an encoder or the like to detect the traveling distance information of the robot cleaner 100.

The control unit 135 controls the overall operation of the robot cleaner 100 and determines that charging (or dust discharge) is necessary in the process of performing the cleaning operation while the robot cleaner 100 travels in a predetermined wall reference travel pattern The cleaning operation is stopped, and control is performed to return to the docking station 200 to perform charging (or dust discharge). The control unit 135 calculates the return distance D by using the estimated position information of the robot cleaner 100 at the time of traveling before stopping the cleaning operation and the robot cleaner 100 performs the wall- And the cleaning operation is restarted after returning to the stopped area.

The driving unit 140 drives the left and right wheels 141 and 142 provided at the lower portion of the robot cleaner main body so that the robot cleaner 100 can change directions such as rotation while the robot cleaner 100 travels by itself in accordance with the control signal of the controller 135.

The suction unit 145 performs a cleaning operation for sucking foreign substances such as dust from the bottom surface of the robot cleaner 100 in accordance with a control signal from the controller 135.

The storage unit 150 stores a predetermined traveling pattern and estimated position information (coordinate, direction) and obstacle information of the robot cleaner 100 (at a specific point) obtained in the running process of the robot cleaner 100, And the wall follow-up distance d _wall calculated by the controller 135 using the estimated position information of the wall position information.

5 is a diagram for explaining a kinematic model of a differential wheel drive robot cleaner and an odometry operation for dead-reckoning. Unless a device such as a camera (vision system) for recognizing the position of the robot cleaner 100 is installed in the robot cleaner system, the robot cleaner 100 accurately detects the position (coordinates, direction) There is no recognizable way. Therefore, a method of estimating the position (coordinate, direction) of the robot cleaner 100 through an odometry operation is used. The odometry operation is performed by using the coordinates (x _t , y _t ) and the direction (x, y) of the robot cleaner 100 at time t as shown in FIG. 5 using the following expressions θ _t) from say a method of estimating the coordinates (x _{t + 1,} y _{t + 1)} and the direction (θ _{t + 1)} of the robot cleaner 100 according to the time t + 1. At this time, it is assumed that there is a time interval between the time t and the time t + 1 by a control period T (a short time of about several ms).

………………………(1)

... ... ... ... ... ... ... ... ... (One)

………………(2)

... ... ... ... ... ... (2)

………………(3)

... ... ... ... ... ... (3)

Here, the variables shown in the above equations have the following meanings.

(x _t , y _t ), (x _{t + 1} , y _{t + 1} ): x and y coordinates of the robot cleaner 100 at sampling times t and t +

θ _t and θ _{t +1} are the heading angles of the robot cleaner 100 at the sampling times t and t + 1. When the steering angle θ is read counterclockwise with respect to the x axis, ) Angle in the clockwise direction and (-) angle in the clockwise direction.

b: Distance between left and right wheels

d _l and d _{r represents} the traveling distance of the left and right wheels 141 and 142 and represents the forward positive value and the negative backward direction based on the traveling direction of the robot cleaner 100,

d _c : Travel distance in the center of the robot cleaner (100)

When the above-described odometry operation is continuously accumulated for every control cycle T, a guiding navigation for estimating the current position of the robot cleaner 100 is performed.

The dotted line in FIG. 6A is a running locus of the robot cleaner to which the RWM algorithm described above is applied. The robot cleaner 100 returns to the docking station 200 due to insufficient remaining battery capacity while performing cleaning while traveling along the locus shown by the dotted line in FIG. 6A with the point S as a starting point, If it is necessary to perform cleaning, the robot cleaner travels on the basis of the estimated distance information (coordinates) stored in the running process before returning to the docking station 200 (before stopping the cleaning) D) is calculated and used to return to the cleaning interruption area. However, in the present invention, it is assumed that the robot cleaner 100 starts cleaning (running) with the docking station 200 as a starting point. That is, in FIG. 6A, the point S becomes the position of the docking station 200.

The robot cleaner 100 detects the coordinates of the point (S, P2) at which the wall follow-up starts (for example, S and P2) in the course of referring to the wall before returning to the docking station 200 D2, d4,...) Calculated by calculating the distance between the two points (the starting point and the ending point of the wall surface tracking) is stored in the storage unit 150. In this case, , d16) are stored in the storage unit 150 as well. In addition, it is assumed that d1, d3, d5, ... Distance is calculated by calculating the distance between the end point of the wall follow-up and the start point of the next wall follow-up in the previous running.

For example, if d1 is obtained, P1 ( _xp1 , _yp1 ) where the wall follow-up is completed in the previous running and P2 ( _xp2 , y _p2 ) is calculated and calculated.

………………(4)

... ... ... ... ... ... (4)

The return distance (D) is calculated using the equation D = Σd _wall + Σd _gap , where d _wall is the wall follow-up distance and d _gap is the distance between the trajectories following the wall.

At this time, the point where the robot cleaner 100 returns to the docking station 200 to perform the cleaning again after completing the charging or the like is a locus (wall surface following running locus) shown by a thick solid line in FIG. 6A, It is a point of consultation.

Hereinafter, the running locus (cleaning process) at the time of restoration of the actual robot cleaner 100 after stopping the cleaning and charging (or discharging the dust) will be described with reference to FIGS. 6B and 6C.

6B, when the robot cleaner 100 travels along the locus indicated by the dotted line with the point S as the starting point and stops cleaning at the point Q due to charging or the like, the return distance D is calculated as Σd _wall (d0 + d2 d + d12 + d12 + d8 + d10 + d12 +? d14) and Σd _gap (d1 + d3 + d5 + d7 + d11 + d13) (provided that the point Q (or R) As a premise). The robot cleaner 100 performs the following wall following travel by the return distance D calculated through the above-described process, and from the R point (return point) at which the wall-surface following travel is terminated, the original wall reference travel pattern A trajectory), and the cleaning operation for the uncleaned area is re-executed. In the case of FIG. 6B, the cleaning stop point Q and the cleaning return point R coincide with each other since the point Q where the cleaning is stopped exists on the wall surface following trajectory.

In the case of FIG. 6C, if the robot cleaner 100 travels along the locus indicated by the dotted line with the point S as the starting point and stops cleaning at the point Q due to charging or the like, the return distance D is calculated as Σd _wall (d0 + d2 + d4 + d6) and sigma d _gap (d1 + d3 + d5). The robot cleaner 100 performs the wall-following following travel by the calculated return distance D through the above-described process, and from the R point (return point) at which the wall-side following travel is terminated, the original wall reference travel pattern A trajectory), and the cleaning operation for the uncleaned area is re-executed. In the case of FIG. 6C, since the point Q where the cleaning is stopped does not exist on the trajectory of the wall-following trajectory, the robot cleaner 100 moves to the wall-side following driving route R, which is the final position before returning to the docking station 200, At this time, the cleaning stop point Q and the cleaning return point R become inconsistent. Accordingly, the cleaning (distance) between the point Q and the point R is redundant.

Hereinafter, a method of controlling the robot cleaner system according to an embodiment of the present invention will be described with reference to FIG.

When the user inputs an operation start signal through the input unit 110 in step 310, the control unit 135 reads the previously stored driving pattern in the storage unit 150 and then outputs the driving pattern to the driving unit 140 and the absorption unit 145 And sends a control signal. Accordingly, the robot cleaner 100 travels in accordance with a predetermined wall reference travel pattern to perform a cleaning operation (320).

The control unit 135 determines whether the remaining amount of the rechargeable battery 115 is insufficient (that is, the remaining capacity of the rechargeable battery 115) by using the detection result of the remaining battery capacity detecting unit 120, (Or dust discharge) command through the charging (or dust discharging) function key of the input unit 110 from the user, or to determine whether the charging battery 115 needs to be charged It is determined whether there is an input of a signal (330).

If it is determined that the remaining amount of the rechargeable battery 115 is equal to or greater than the set value and there is no need to discharge dust and the charge (or dust discharge) command signal is not input from the user (NO at step 330) The robot cleaner 100 returns to step 320 and continues to perform the cleaning operation while traveling in the wall reference travel pattern.

On the other hand, if it is determined that the remaining amount of the rechargeable battery 115 is low or dust is required to be discharged, or if there is input of a charging (or dust discharge) command signal from the user (YES in step 330) A control signal is sent to the driving unit 140 and the suction unit 145 to temporarily stop the cleaning operation being performed. The control unit 135 checks the sensing signal from the receiving unit 105 and sends a control signal to the driving unit 140 so that the robot cleaner 100 returns to the docking station 200 to charge the rechargeable battery 115, (340). ≪ / RTI >

Next, the controller 135 obtains the estimated position information (coordinates (x, y), direction (?)) Of the robot cleaner 100 stored in the storage unit 150 and the formula D = The return distance D is calculated 350 using the 裡 d _wall + 裡 d _gap . Where d _wall is the wall follow-up distance, and d _gap is the distance between the track following the wall.

Then, the control unit 135 sends a control signal to the driving unit 140 to control the robot cleaner 100 to follow the wall by the return distance D calculated in step 350 (360).

Next, when the robot cleaner 100 has performed the wall-following following traveling by the return distance D, the control unit 135 sends a control signal to the driving unit 140 and the suction unit 145, (370) so that the cleaning operation for the uncleaned area is performed again while traveling according to the wall reference travel pattern (before the stop).

As a result, it is possible to prevent double cleaning of the cleaning area before returning to the docking station 200 for charging or the like (before the cleaning is stopped), and cleaning of the uncleaned area becomes possible.

FIG. 1 is a trajectory of a wall-following trajectory in the case where a left-hand traveling algorithm running along the left wall surface is applied.

FIG. 2 is a travel locus diagram (cleaning order diagram) of a robot cleaner to which an RWM (Reference Wall Based Matrix) algorithm, which is an example of a wall reference travel pattern, is applied.

3 is a view showing various types of wall reference travel patterns.

4 is a control block diagram of a robot cleaner system according to an embodiment of the present invention.

5 is a diagram for explaining a kinematic model of a differential wheel drive robot cleaner and an odometry operation for dead-reckoning.

FIG. 6A is a view for explaining the concept of a travel locus and a return distance D of a robot cleaner to which a reference wall based matrix (RWM) algorithm is applied, which is an example of a wall reference travel pattern. FIGS. (Cleaning process) at the time of returning after returning (or discharging) dust.

7 is a flowchart illustrating a method of controlling a robot cleaner system according to an embodiment of the present invention.

Description of the Related Art [0002]

100: robot cleaner 105:

110: input unit 120: battery remaining amount detection unit

125: Obstacle detecting unit 130: Odometer detecting unit

135: control unit 140:

145: suction unit 150:

200: docking station 210:

220:

Claims (6)

Performing a cleaning operation while the robot cleaner travels in a wall reference travel pattern; Stopping the cleaning operation and returning to the docking station for charging or discharging dust; Calculating a return distance for moving the robot cleaner to a cleaning stop area using position information of the robot cleaner before stopping the cleaning operation; And controlling to restart the cleaning operation after returning to the cleaning stop area by following the wall by the return distance, Wherein the robot cleaner starts the cleaning operation using the position of the docking station as a start point The method according to claim 1, The control method of the robot cleaner system is a pattern in which the wall reference travel pattern repeats a series of processes of following the reference wall surface → departing from the reference wall surface → moving by a certain distance → returning to the reference wall surface The method according to claim 1, The position information of the robot cleaner before stopping the cleaning operation is estimated from the position information of the robot cleaner at time t by using an odometry operation for estimating the position information of the robot cleaner at time t + Wherein the position information of the robot cleaner before stopping the cleaning operation includes a position of a point where the follow-up of the reference wall surface starts and a position of a point where the follow-up of the reference wall surface ends, The method of claim 3, The return distance D is calculated using the formula D = Σd _wall + Σd _gap (where d _wall is the wall follow-up distance, and d _gap is the distance between traces following the wall) delete The method according to claim 1, A control method of the robot cleaner system for restarting the cleaning of the uncleaned area while traveling in the wall reference travel pattern from the end point of the wall-

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