Robot cleaner and control method for the same

Abstract

A robot cleaner includes a body to travel on a floor, an obstacle sensing unit to sense an obstacle approaching the body, an auxiliary cleaning unit mounted to a bottom of the body, to be extendable and retractable, and a control unit to control extension or retraction of the auxiliary cleaning unit when the obstacle is sensed, through adjustment of an extension or retraction degree of the auxiliary cleaning unit.

What is claimed is: 
     
         1 . A robot cleaner comprising:
 a body to travel on a floor;   an obstacle sensing unit to sense an obstacle approaching the body;   an auxiliary cleaning unit mounted to a bottom of the body, to be extendable and retractable; and   a control unit to control extension or retraction of the auxiliary cleaning unit by adjusting an extension or retraction degree of the auxiliary cleaning unit when the obstacle is sensed.   
     
     
         2 . The robot cleaner according to  claim 1 , wherein:
 the auxiliary cleaning unit is pivotably mounted to the bottom of the body; and   the control unit adjusts the extension or retraction of the auxiliary cleaning unit, based on a pivot angle formed by the auxiliary cleaning unit with respect to a travel direction of the body.   
     
     
         3 . The robot cleaner according to  claim 2 , wherein the control unit adjusts the extension or retraction degree of the auxiliary cleaning unit such that a distance between an outermost portion of the auxiliary cleaning unit and the obstacle is greater than a predetermined first critical value, but smaller than a predetermined second critical value. 
     
     
         4 . The robot cleaner according to  claim 1 , wherein the control unit compares an output signal from the obstacle sensing unit according to a sensing direction of the obstacle sensing unit with a predetermined critical value, and adjusts the extension or retraction degree of the auxiliary cleaning unit, based on a result of the comparison. 
     
     
         5 . The robot cleaner according to  claim 4 , wherein the predetermined critical value corresponds to a distance from the body to an outermost portion of the auxiliary cleaning unit. 
     
     
         6 . The robot cleaner according to  claim 1 , wherein the control unit adjusts the extension or retraction degree of the auxiliary cleaning unit, based on an output signal from the obstacle sensing unit according to an extension direction of the auxiliary cleaning unit. 
     
     
         7 . The robot cleaner according to  claim 6 , wherein the control unit adjusts the extension or retraction degree of the auxiliary cleaning unit in proportion to the output signal. 
     
     
         8 . A robot cleaner comprising:
 a body to travel on a floor;   an obstacle sensing unit to sense an obstacle approaching the body;   at least one auxiliary cleaning unit mounted to a bottom of the body, to be extendable and retractable; and   a control unit to control extension or retraction of the auxiliary cleaning unit in accordance with a shape of the sensed obstacle when the obstacle is sensed.   
     
     
         9 . The robot cleaner according to  claim 8 , wherein the control unit controls the extension or retraction of the auxiliary cleaning unit when the obstacle has a flat wall shape such that the auxiliary cleaning unit is retracted after being maintained in an extended state for a predetermined time, or is extended after being maintained in a retracted state for a predetermined time. 
     
     
         10 . The robot cleaner according to  claim 9 , wherein:
 the at least one auxiliary cleaning unit comprises at least two auxiliary cleaning units mounted to the bottom of the body; and   when the obstacle is sensed only at a lateral side of the body, the control unit only controls extension or retraction of the auxiliary cleaning unit, which is disposed in a direction corresponding to the obstacle, among the at least two auxiliary cleaning units.   
     
     
         11 . The robot cleaner according to  claim 8 , wherein:
 the at least one auxiliary cleaning unit comprises at least two auxiliary cleaning units mounted to the bottom of the body; and   when the obstacle has a corner wall shape, the control unit controls extension or retraction of the auxiliary cleaning units, which are disposed at opposite sides of the body, among the at least two auxiliary cleaning units.   
     
     
         12 . The robot cleaner according to  claim 8 , wherein the control unit controls the extension or retraction of the auxiliary cleaning unit when the shape of the obstacle has a smaller size than a reference size. 
     
     
         13 . A robot cleaner comprising:
 a body to travel on a floor;   an obstacle sensing unit to sense an obstacle approaching the body;   at least one auxiliary cleaning unit mounted to a bottom of the body, to be extendable and retractable; and   a control unit to control extension or retraction of the auxiliary cleaning unit in accordance with a travel direction of the body when the obstacle is sensed.   
     
     
         14 . The robot cleaner according to  claim 13 , wherein the control unit controls the auxiliary cleaning unit to be retracted before and after rotation of the body or before and after backward movement of the body. 
     
     
         15 . The robot cleaner according to  claim 14 , wherein:
 the at least one auxiliary cleaning unit comprises at least two auxiliary cleaning units mounted to the bottom of the body around the body; and   the control unit controls extension or retraction of the auxiliary cleaning units in accordance with a rotation direction of the body such that a preceding one of the auxiliary cleaning units in the rotation direction of the body is retracted.   
     
     
         16 . The robot cleaner according to  claim 14 , wherein the control unit controls extension degrees of the auxiliary cleaning units in accordance with a rotation direction of the body such that a preceding one of the auxiliary cleaning units in a direction opposite to the rotation direction of the body has an increased extension degree. 
     
     
         17 . The robot cleaner according to  claim 14 , wherein the control unit adjusts a travel speed of the body or a rotation speed of an auxiliary cleaning tool coupled to the auxiliary cleaning unit when the body rotates. 
     
     
         18 . A robot cleaner comprising:
 a body to travel on a floor;   an obstacle sensing unit to sense an obstacle approaching the body;   an auxiliary cleaning unit mounted to a bottom of the body, to be extendable and retractable; and   a control unit to control extension or retraction of the auxiliary cleaning unit in accordance with a cleaning mode of the body when the obstacle is sensed.   
     
     
         19 . The robot cleaner according to  claim 18 , wherein the control unit performs a control operation to prevent the auxiliary cleaning unit from extending when a cleaning operation is completed. 
     
     
         20 . The robot cleaner according to  claim 19 , wherein the control unit performs a control operation to prevent the auxiliary cleaning unit from extending when the obstacle is determined to be a charger or an exhaust station during return of the body to the charger or the exhaust station. 
     
     
         21 . The robot cleaner according to  claim 20 , further comprising:
 a signal sensing unit to sense a discriminating signal for the charger or the exhaust station.   
     
     
         22 . The robot cleaner according to  claim 21 , wherein the discriminating signal is an infrared signal, a radio frequency (RF) signal, or a magnetic field signal. 
     
     
         23 . The robot cleaner according to  claim 18 , wherein the control unit performs a control operation to prevent the auxiliary cleaning unit from extending for a predetermined time when a cleaning operation starts in accordance with an automatic cleaning mode. 
     
     
         24 . The robot cleaner according to  claim 18 , wherein the control unit performs a control operation to prevent the auxiliary cleaning unit from extending when the body performs a charging operation. 
     
     
         25 . The robot cleaner according to  claim 24 , wherein the control unit performs a control operation to prevent the auxiliary cleaning unit from extending when the charging operation of the body is completed or when supply of electric power to the charger is stopped. 
     
     
         26 . A control method for a robot cleaner comprising:
 driving a body of the robot cleaner such that the body travels on a floor;   sensing an obstacle approaching the body; and   controlling extension or retraction of an auxiliary cleaning unit mounted to a bottom of the body, to be extendable and retractable, by adjusting an extension or retraction degree of the auxiliary cleaning unit.   
     
     
         27 . The control method according to  claim 26 , wherein:
 the auxiliary cleaning unit is pivotably mounted to the bottom of the body; and   the controlling the extension or retraction of the auxiliary cleaning unit is executed, based on a pivot angle formed by the auxiliary cleaning unit with respect to a travel direction of the body.   
     
     
         28 . The control method according to  claim 27 , wherein the controlling the extension or retraction of the auxiliary cleaning unit is executed such that a distance between an outermost portion of the auxiliary cleaning unit and the obstacle is greater than a predetermined first critical value, but smaller than a predetermined second critical value. 
     
     
         29 . The control method according to  claim 26 , wherein the controlling the extension or retraction of the auxiliary cleaning unit is executed, based on a result of a comparison between an output signal from the obstacle sensing unit according to a sensing direction of the obstacle sensing unit and a predetermined critical value. 
     
     
         30 . The control method according to  claim 29 , wherein the predetermined critical value corresponds to a distance from the body to an outermost portion of the auxiliary cleaning unit. 
     
     
         31 . The control method according to  claim 26 , wherein the controlling the extension or retraction of the auxiliary cleaning unit is executed, based on an output signal according to an obstacle sensing direction, along which the auxiliary cleaning unit extends. 
     
     
         32 . The control method according to  claim 31 , wherein the controlling the extension or retraction of the auxiliary cleaning unit is executed in proportion to the output signal. 
     
     
         33 . A robot cleaner comprising:
 a body to travel along a floor;   a main brush unit;   a power supply,   first and second drive wheels;   a caster;   at least one auxiliary cleaning unit, the auxiliary cleaning unit being extendable and retractable in a radial direction of the body, and comprising;
 a side arm coupled to a front portion of a bottom of the body at one side of the body, the side arm being pivotable about a first coupling groove formed at one end of the side arm; 
 a second coupling groove formed at an other end of the side arm; 
 an auxiliary cleaning tool rotatably coupled to the second coupling groove; and 
 a periphery cover attached to the other end of the side arm, the periphery cover forming an outer surface of the body when the auxiliary cleaning unit is in a fully retracted position, 
   an obstacle sensing unit to sense an obstacle approaching the body;   a control unit to control extension or retraction of the auxiliary cleaning unit,   wherein the control unit adjusts the extension or retraction of the auxiliary cleaning unit based on a pivot angle of the side arm with respect to a travel direction of the body.   
     
     
         34 . The robot cleaner according to  claim 33 , wherein the control unit adjusts the extension or retraction degree of the auxiliary cleaning unit such that a distance between an outermost portion of the auxiliary cleaning unit and the obstacle is greater than a predetermined first critical value, but smaller than a predetermined second critical value.