Abstract:
Provided are a method and apparatus for ensuring a cleaning robot to return to a charge station. The method includes the steps of: (a) measuring a battery usable time, a running speed, and an actual return distance of a cleaning robot during a cleaning operation; (b) calculating an allowable return distance on the basis of the battery usable time and the running speed; (c) comparing the actual return distance with the allowable return distance; and (d) returning the cleaning robot to the charge station when the actual return distance is larger than the allowable return distance as a result of the comparison. Therefore, it is possible to prevent the cleaning robot from being not returned to the charge station, thereby providing convenience to a user.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Korean Patent Application No. 2006-122329, filed Dec. 5, 2006, and No. 2007-12253, filed Feb. 6, 2007, the disclosure of which is hereby incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a method and apparatus for recharging a cleaning robot, and more particularly, to a method and apparatus for ensuring a cleaning robot to return to a charge station. 
         [0004]    The present invention has been produced from the work supported by the IT R&amp;D program of MIC (Ministry of Information and Communication)/IITA (Institute for Information Technology Advancement) [2005-S-026-02, Development of Embedded Software Platform and Middleware for URC] in Korea. 
         [0005]    2. Discussion of Related Art 
         [0006]    Generally, a cleaning robot is equipped with a rechargeable battery to automatically make a round in an interior space to clean the interior space. The cleaning robot equipped with the rechargeable battery performs a cleaning operation by automatically making the round in the interior space, and checks a voltage level of the battery by measuring the voltage of the battery to determine a battery recharge time at predetermined time intervals. When the battery recharge time is detected, the robot should return to a charge station, positioned at one corner of the interior, to automatically recharge the battery. 
         [0007]    When the voltage of the battery becomes lower than a certain level, a conventional cleaning robot stops a cleaning operation and moves to the charge station by recognizing robot position information and charger position information stored in a controller. However, when a recharge time of the cleaning robot is determined using the battery voltage only, there is no problem when a distance between the cleaning robot and the charge station is short; whereas if the station is too far away, the battery may be fully exhausted while returning to the charge station so that the cleaning robot stops before arriving at the charge station. In addition, when a bottom surface of the interior in which the cleaning robot moves is too slippery to perform the cleaning operation, the battery of the cleaning robot may be exhausted to make it impossible to return to the charge station and perform the cleaning operation, thereby causing inconvenience to a user. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed to an apparatus and method for ensuring a cleaning robot to return to a charge station. 
         [0009]    An aspect of the present invention provides a method for returning a cleaning robot to a charge station, including the steps of: (a) measuring a battery usable time, a running speed, and an actual return distance of a cleaning robot during a cleaning operation; (b) calculating an allowable return distance on the basis of the battery usable time and the running speed; (c) comparing the actual return distance with the allowable return distance; and (d) returning the cleaning robot to the charge station when the actual return distance is larger than the allowable return distance as a result of the comparison. 
         [0010]    Another aspect of the present invention provides a method for returning a cleaning robot to a charge station, including the steps of: (a) measuring a battery usable time when a cleaning robot is booted; (b) determining whether the cleaning robot is connected to the charge station when the measured battery usable time is less than a battery usable reference time; (c) starting to return to the charge station when the cleaning robot is not connected to the charge station, and measuring a running speed of the cleaning robot and an actual return distance; (d) calculating an allowable return distance on the basis of the battery usable time and the running speed; (e) comparing the actual return distance with the allowable return distance; and (f) generating an alarm when the actual return distance is larger than the allowable return distance as a result of the comparison. 
         [0011]    Still another aspect of the present invention provides an apparatus for returning a cleaning robot to a charge station, including: a battery detection part for measuring a battery usable time of a cleaning robot; a running speed detection part for measuring a running speed of the cleaning robot; a return distance detection part for measuring an actual return distance of the cleaning robot; and a controller for comparing the actual return distance with an allowable return distance, and returning the cleaning robot to the charge station when the actual return distance is larger than the allowable return distance. 
         [0012]    Yet another aspect of the present invention provides an apparatus for returning a cleaning robot to a charge station, including: a battery detection part for measuring a battery usable time of the cleaning robot when the cleaning robot is booted; a running speed detection part for measuring a running speed of the cleaning robot; a return distance detection part for measuring an actual return distance of the cleaning robot; and a controller for calculating an allowable return distance on the basis of the battery usable time and the running speed when the battery usable time is less than a battery usable reference time and the cleaning robot is not connected to the charge station, and outputting an alarm when the actual return distance is larger than the allowable return distance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which: 
           [0014]      FIG. 1  is a block diagram of a cleaning robot and a charge station in accordance with an exemplary embodiment of the present invention; 
           [0015]      FIG. 2  is a control flowchart for setting cleaning reference information of the cleaning robot in accordance with an exemplary embodiment of the present invention; 
           [0016]      FIGS. 3A and 3B  show screens for setting the cleaning reference information of the cleaning robot in accordance with an exemplary embodiment of the present invention; 
           [0017]      FIG. 4  is a flowchart showing a control process of returning the cleaning robot to the charge station in accordance with an exemplary embodiment of the present invention; and 
           [0018]      FIGS. 5A to 5C  are views showing a process of returning the cleaning robot to the charge station in accordance with an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0019]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. 
         [0020]      FIG. 1  is a block diagram of a cleaning robot and a charge station in accordance with an exemplary embodiment of the present invention. Hereinafter, basic configuration and operation of a cleaning robot  100  and a charge station  120  in accordance with an exemplary embodiment of the present invention will be described with reference to  FIG. 1 . 
         [0021]    A controller  101  processes various functions of the cleaning robot  100 . In particular, the controller  101  in accordance with an exemplary embodiment of the present invention receives a battery usable time measured by a battery detection part  109 , a distance between the cleaning robot  100  and the charge station  120  measured by a return distance detection part  111 , and a running speed of the cleaning robot  100  measured by a running speed detection part  107  during a cleaning operation, and compares the distance between the cleaning robot  100  and the charge station  120  with an allowable return distance calculated by the following Formula 1. 
         [0000]      Allowable return distance=Battery usable time×Running speed−Allowable moving distance   [Formula 1] 
         [0022]    Hereinafter, the distance between the cleaning robot  100  and the charge station  120  will be referred to as an ‘actual return distance’. In this process, the allowable return distance is a distance for correcting an error, which may be generated due to a slippery surface on which the cleaning robot  100  moves, or a calculation error of the distance to the charge station  120  due to direction changes of the cleaning robot  100 . At this time, when the actual return distance is larger than the allowable return distance, a current position of the cleaning robot  100  is stored in a memory part  102 , and the cleaning robot  100  returns to the charge station  120 . In addition, the controller  101  generates an alarm through a speaker SPK to allow a user to guide the cleaning robot  100  to the charge station  120 . 
         [0023]    The memory part  102  provides a region for storing micro codes of a program for processing and controlling the controller  101 , and various storage data. In particular, the memory part  102  in accordance with an exemplary embodiment of the present invention stores cleaning reference information such as a battery usable time, an allowable moving distance, and so on. The cleaning reference information may be set by a user or previously set. For example, the user may set the allowable moving distance on the basis of a bottom material of a space to be cleaned. 
         [0024]    A key input part  103  includes various keys to provide key input data corresponding to a key pressed by a user on the controller. In particular, in accordance with an exemplary embodiment of the present invention, the user may set the cleaning reference information using keys installed at the key input part  103 . A display part  104  displays an image representing various operation information provided from the controller  101  under control of the controller  101 . 
         [0025]    A motor drive part  105  drives wheels  106  to move the cleaning robot in any direction under control of the controller  101 . The running speed detection part  107  measures the speed of the wheels  106  using a speedometer and so on to output the speed to the controller  101 . While the motor drive part  105  and the running speed detection part  107  in accordance with the present invention are shown in a divided manner for ease of understanding, the motor drive part  105  may include the running speed detection part  107 . 
         [0026]    A suction part  108  drives a motor installed therein to suck dust and so on under control of the controller  101 . A power supply  110  is connected to a power supply  121  of the charge station  120  to recharge required power to the battery for operating the cleaning robot  100 . The battery detection part  109  periodically measures remaining power of the battery installed in the power supply  110  and outputs the data to the controller  101 . While the power supply  110  and the battery detection part  109  in accordance with the present invention are shown in a divided manner for ease of understanding, the power supply  110  may include the battery detection part  109 . 
         [0027]    A sensor part  112  generates an ultrasonic wave and so on and detects the ultrasonic wave reflected by an object. The returning distance detection part  111  measures the distance between the cleaning robot  100  and the charge station  120  and then outputs the data to the controller  101 . A method of measuring the distance between the cleaning robot  100  and the charge station  120  may be implemented using technology well-known in this field, so description of a specific measuring process will be omitted. The charge station power supply  121  is connected to the power supply  110  of the cleaning robot  100  to transmit power required for operating the cleaning robot  100  to the cleaning robot  100 . 
         [0028]      FIG. 2  is a control flowchart for setting cleaning reference information of the cleaning robot in accordance with an exemplary embodiment of the present invention, and  FIGS. 3A and 3B  show screens for setting the cleaning reference information of the cleaning robot in accordance with an exemplary embodiment of the present invention. Hereinafter, a method for setting cleaning reference information of the cleaning robot  100  will be described with reference to  FIGS. 2 ,  3 A and  3 B. 
         [0029]    During step  200  of  FIG. 2 , the controller  101  determines whether a request for setting cleaning reference information of the cleaning robot  100  is applied through the key input part  103  by a user. When the cleaning reference information setting request is applied, the controller  101  performs step  202 . In step  202 , the controller  101  displays a management screen for enabling a user to set the cleaning reference information through the display part  104  and then performs step  204 . In step  204 , the controller  101  determines whether a user sets cleaning reference information. When the user sets the cleaning reference information, the controller performs step  206 . In step  206 , the controller  101  stores the cleaning reference information set by the user in the memory part  102  and completes the cleaning operation. 
         [0030]    Hereinafter, the method of setting cleaning reference information will be described with reference to  FIG. 3 . 
         [0031]      FIG. 3A  shows an example of a management screen for enabling a user to set a battery usable reference time of the cleaning robot, and  FIG. 3B  shows an example of a management screen for enabling a user to set an allowable moving distance of the cleaning robot  100 . When a user sets the battery usable reference time to “2 hours 00 minutes” as shown in  FIG. 3A , the cleaning robot returns to the charge station  120  to recharge the battery when the remaining battery capacity is less than two hours in booting the cleaning robot  100 , and then starts to perform a cleaning operation after recharging the battery in the charge station until the remaining battery capacity arrives at two hours. 
         [0032]      FIG. 4  is a flowchart showing a control process of returning the cleaning robot to the charge station in accordance with an exemplary embodiment of the present invention, and  FIGS. 5A to 5C  are views showing a process of returning the cleaning robot to the charge station in accordance with an exemplary embodiment of the present invention. Hereinafter, a process of returning the cleaning robot  100  to the charge station  120  in accordance with an exemplary embodiment of the present invention will be described with reference to  FIGS. 4 and 5A  to  5 C. 
         [0033]    In step  400  of  FIG. 4 , the controller  101  periodically receives a battery usable time measured by the battery detection part  109  and then performs step  402 . In step  402 , the controller  101  compares the battery usable time with a battery usable reference time. When the battery usable time is larger than the battery usable reference time, the controller  101  moves to step  404 , and when the battery usable time is less than the battery usable reference time, the controller  101  performs step  430 . 
         [0034]    In step  404 , the controller  101  determines whether a cleaning start position is stored in the memory part  102 . When the cleaning memory part is stored, the controller performs step  406 , and when not stored, the controller  101  performs step  408 . In step  406 , the controller  101  moves the cleaning robot  100  to the cleaning start position stored in the memory part  102 . In step  408 , the controller  101  begins a cleaning operation. 
         [0035]    In step  410 , the controller  101  determines whether the cleaning operation is completed. When the cleaning operation is completed, the controller  101  performs step  412 , and when not completed, the controller  101  performs step  420 . In step  412 , the controller  101  returns the cleaning robot  100  to the charge station  120 . In step  414 , the controller  101  recharges the cleaning robot  100  and completes the cleaning operation. 
         [0036]    Meanwhile, in step  420  performed by determining that the cleaning operation is not completed during step  410 , the controller  101  receives a battery usable time measured by the battery detection part  109 , an actual return distance measured by the return distance detection part  111 , and a running speed measured by the running speed detection part  107 , calculates an allowable return distance using Formula 1, and then performs step  422 . In step  422 , the controller  101  compares the actual return distance with the allowable return distance. When the actual return distance is larger than the allowable return distance, the controller  101  performs step  424 , and when the actual return distance is smaller than the allowable return distance, the controller  101  performs step  408 . In step  424 , the controller  101  stores a current position of the cleaning robot  100  in the memory part  102 , and performs step  426 . 
         [0037]    In step  426 , the controller  101  returns the cleaning robot  100  to the charge station  120 , and performs step  440 . In step  440 , the controller  101  recharges the cleaning robot  100 , and performs step  400 . 
         [0038]    Meanwhile, in step  430  performed as a result of the determination that the battery usable time is less than the battery usable reference time in step  402 , the controller  101  determines whether the cleaning robot  100  is connected to the charge station  120 . When the cleaning robot  100  is connected to the charge station  120 , the controller  101  performs step  440 , and when not connected to the charge station  120 , the controller  101  performs step  432 . 
         [0039]    In step  432 , the controller  101  attempts to return the cleaning robot  100  to the charge station  120 , receives a running speed of the cleaning robot  100  measured by the running speed detection part  107  and an actual return distance measured by the return distance detection part  111 , calculates an allowable return distance using Formula 1, and then performs step  434 . 
         [0040]    In step  434 , the controller  101  compares the actual return distance with the allowable return distance. When the actual return distance is larger than the allowable return distance, the controller  101  performs step  436 , and when the actual return distance is smaller than the allowable return distance, the controller  101  performs step  438 . In step  438 , the controller  101  generates an alarm through the speaker SPK, and performs step  430 . 
         [0041]    Meanwhile, in step  438  performed as a result of step  434 , the controller  101  returns the cleaning robot  100  to the charge station  120 , and performs step  440 . 
         [0042]    Hereinafter, a method of setting cleaning reference information will be described with reference to  FIGS. 5A to 5C . 
         [0043]      FIG. 5A  is a view showing a process of returning the cleaning robot  100  to the charge station  120  to recharge the battery during a cleaning operation in a cleaning region  500 . When it is determined that an actual return distance of the cleaning robot  100  is larger than the allowable return distance during cleaning operations a 501  and a 502 , a current position  510  of the cleaning robot  100  is stored, and the cleaning robot  100  returns (as shown in a dotted arrow a 503 ) to the charge station  120  to recharge the battery. 
         [0044]      FIG. 5B  is a view showing a process of returning the cleaning robot  100  to the charge station  120  after recharging the battery, moving to the stored cleaning start position  510 , and completing cleaning operations b 502  to b 509 . 
         [0045]      FIG. 5C  is a view showing a process (steps  430  to  438  of  FIG. 4 ) of returning (as shown in a dotted arrow c 501 ) the cleaning robot  100  to the charge station  120  when the battery usable time in booting the cleaning robot  100  is less than the battery usable reference time. At this time, when the actual return distance is larger than the allowable return distance, the cleaning robot  100  generates an alarm and attempts to return to the charge station  120 . When a user hears the alarm, moves the cleaning robot  100  and connects the cleaning robot  100  to the charge station  120 , a battery recharge operation is initiated (steps  430  to  440  performed as a result of step  436 ). Meanwhile, when the actual return distance is smaller than the allowable return distance, the cleaning robot  100  returns to the charge station  120  to recharge the battery. 
         [0046]    As can be seen from the foregoing, the present invention improves a method for returning a cleaning robot to a charge station to prevent the cleaning robot from not returning to the charge station, thereby providing convenience to a user. 
         [0047]    Although the present invention has been described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that a variety of modifications and variations may be made to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims and their equivalents.