Abstract:
An vacuum cleaning robot has a drive system adapted to autonomously move a base housing along a horizontal surface and is controlled by a computer processing unit. A dusting assembly is mounted to the base housing and is adapted to selectively rest on a surface to be cleaned. A suction source draws dirt and debris through a suction nozzle and deposits the same in the recovery tank. A power source is connected to the drive system and to the computer processing unit. The computer processing unit is adapted to direct horizontal movement of the base housing within boundaries of the surface to be cleaned based upon input data defining said boundaries.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application Ser. No. 60/319,722, filed Nov. 22, 2002. 

   BACKGROUND OF INVENTION 
   A home cleaning robot comprising a platform in combination with a cleaning implement, for example a non-woven electrostatic cloth, and a motive force to autonomously move the platform is disclosed in U.S. Pat. No. 6,459,955 to Bartsch et al. The robot moves randomly about a surface while cleaning the surface with the cloth. U.S. Pat. No. 6,481,515 to Kirkpatrick et al. describes a similar device with a surface treating sheet and also includes a chamber for storing fluid that is applied to the surface through the surface treating means. Another robotic floor cleaner disclosed in U.S. Patent Application Publication No. 2002/0002751 to Fisher utilizes disposable cleaning sheets, such as dust cloths, engaged with several sheet holder receptacles on a compliant pad. The robotic floor cleaner further comprises an appendage that can have several functions, including a sheet holder or a fluid dispenser. The U.S. Pat. No. 6,633,150 to Wallach et al. discloses a mobile robot that mops a surface by pressing a damp towel, which is mounted to the body of the robot, against the ground as the robot moves back and forth. One limitation of these types of robot cleaners is that larger debris is pushed in front of the robot without being picked up. Another limitation is that the larger debris tends to clog or bind the cloth, thus reducing the useful life of the cloth. A further limitation is that this type of cleaner does not have the capacity to pretreat and agitate stubborn sticky stains, especially from hard surfaces. 
   An automatic robotic vacuum cleaner integrating a drive system, a sensing systems, and a control system with a microprocessor is disclosed in U.S. Patent Application Publication No. 2003/0060928. Examples of commercially available robotic vacuum cleaners include the Roomba vacuum cleaner from iRobot, the Karcher RoboVac, the Robo Vac from Eureka, the Electrolux Trilobite, and the LG Electronics Robot King. Additionally, U.S. Pat. No. 6,594,844 to Jones discloses an obstacle detection system for a robot that is said to dust, mop, vacuum, and/or sweep a surface such as a floor. One limitation of such automatic robotic vacuum cleaners is that fine or embedded debris, such as liquid stains, cannot effectively be removed by a dry vacuum system alone. 
   U.S. Pat. No. 6,457,206 to Judson discloses a remote-controlled vacuum cleaner that is operable in an automatic mode and has a mister for distributing cleaning solution or water onto the surface to loosen debris during movement of the vacuum cleaner. U.S. Pat. No. 5,309,592 to Hiratsuka discloses a cleaning robot having rotary brushes and a squeegee to collect soiled water and dust for removal by suction. Further examples of robotic cleaners are disclosed in U.S. Pat. No. 5,279,672 to Betker et al., U.S. Pat. No. 5,032,775 to Mizuno et al., and U.S. Pat. No. 6,580,246 to Jacobs, which all disclose devices that comprise some type of fluid dispensing system, agitation system, and vacuum/fluid collection system. 
   SUMMARY OF INVENTION 
   According to the invention, an autonomously movable home cleaning robot comprises a base housing, a drive system mounted to said base housing wherein the drive system is adapted to autonomously move the base housing on a substantially horizontal surface having boundaries. Further, a computer processing unit for storing, receiving and transmitting data is attached to said base housing, a dusting assembly is operatively associated with the base housing and is adapted to selectively rest on a surface to be cleaned. A suction nozzle is mounted on the base housing for withdrawing dirt and debris from the surface to be cleaned and a recovery tank is mounted on the base housing and is in fluid communication with the suction nozzle. A suction source is mounted to the base housing and is in fluid communication with the suction nozzle and the recovery tank for drawing dirt and debris through the suction nozzle and for depositing the same in the recovery tank. A power source is connected to the drive system and to the computer processing unit. The computer processing unit is adapted to direct horizontal movement of the base housing within the boundaries of the surface to be cleaned based upon input data defining said boundaries. 
   In one embodiment, the cleaning robot further comprises a cleaning fluid delivery system for depositing a cleaning fluid on the surface to be cleaned. Further, an agitator can be mounted on the base housing for agitating contact with the surface to be cleaned. 
   Preferably, the cleaning robot further includes floor condition sensors mounted on the base housing for detecting a floor condition and for generating a control signal that forms a part of the input data to the computer processing unit. Further, the computer processing unit controls at least one of the agitator, the delivery of fluid by the fluid delivery system, the suction source and the drive system in response to the control signal. In a preferred embodiment, proximity sensors are mounted on base housing for detecting the boundaries of the surface to be cleaned and for generating a second control signal that forms a part of the input data to the computer processing unit. The computer processing unit controls the drive system in response to the second control signal to keep the base housing within the boundaries of the surface to be cleaned. 
   In one embodiment, the input data is a remote control signal. In another embodiment, the input data comprises a program that guides the base assembly through a predetermined path on the surface to be cleaned. 
   Typically, the drive system comprises at least one wheel that is driven by a drive motor. 
   In a preferred embodiment, the dusting cloth is removably mounted to a pad that forms a support for the dusting cloth. 
   Further according to the invention, a method of autonomously cleaning a surface comprising the steps of: applying a suction force to the surface through a suction nozzle to remove dirt and debris from the surface, collecting the removed dirt and debris in a collection chamber, substantially simultaneously applying a dusting cloth to the surface to be cleaned and guiding the application of the suction force and the dusting cloth with the use of input data to a central processing unit. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     In the drawings: 
       FIG. 1  is a perspective view of the robotic extraction cleaner with dusting pad according to the invention. 
       FIG. 2  is a perspective bottom view of the robotic extraction cleaner with dusting pad in the operating position as shown in  FIG. 1 . 
       FIG. 3  is an exploded view of the robotic extraction cleaner with dusting pad shown in  FIG. 1 . 
       FIG. 4  is a partial cross-sectional side view of the base assembly taken across line  4 - 4  of  FIG. 1 . 
       FIG. 5  is a schematic block diagram of the robotic extraction cleaner with dusting pad as shown in  FIG. 1 . 
       FIG. 6  is a plan view of the robotic extraction cleaner with dusting pad as shown in  FIG. 1 . 
       FIG. 7  is a perspective bottom view of the robotic extraction cleaner with dusting pad in open position as shown in  FIG. 1 . 
       FIG. 8  is a perspective bottom view of the dusting pad of the robotic extraction cleaner with dusting pad as shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1-3 , a robotic extraction cleaner  10  with dusting pad is described and comprises robotic platform further comprising a top enclosure  12  and a base housing  14 . The base housing  14  provides the basic structure for the robotic platform on which all other components depend for structural support. A clean solution tank  16  is removably mounted in a solution tank recess  18  formed within the top enclosure  12 . A generally conical shaped recovery tank  20  is removably mounted to a flat surface formed on a top surface of top enclosure  12 . A plurality of proximity sensors  24 ,  26  are located within corresponding sensor apertures  22  around the outer periphery of the top enclosure  12 . The proximity sensors  24 ,  26  comprise any one or combination of commonly known sensors including infrared sensors  24 , pressure sensitive sensors  26 , or ultrasonic sensors affixed to the top enclosure  12  in alternating or parallel fashion. Alternating the arrangement of proximity sensors  24 ,  26  provides redundancy and allows for improved motion control of the robotic platform as it encounters obstacles within the room being cleaned. An electrical power switch  28  is located on a top surface of the top enclosure  12 , preferably near the recovery tank  20 , and controls the flow of power from one or more batteries  44  to a logic board  46 , both mounted to the base housing  14  within a cavity formed by the top enclosure  12 . 
   Alternatively, or in combination with the proximity sensors  24 ,  26 , a predetermined path is programmed in to the central processing unit by the user. In yet another embodiment, the path is dictated to the central processing unit via a remote control device. 
   Referring to  FIGS. 2 and 3 , a drive system comprises a pair of drive wheels  30  that protrude through corresponding drive wheel apertures  32  which are located in spaced relation near the outer perimeter of the base  14 . A brush roll  34  protrudes through a corresponding suction aperture  36  forming a forward portion of the base  14 . A plurality of floor condition sensors  38  are mounted within corresponding condition sensor apertures  39  located through the bottom surface of the base  14  on both the forward and rearward portion of the base  14 . A dusting pad  40  is attached to a bottom surface of the base  14  behind and in spaced relation to the brush roll  34  and the drive wheels  30 . The dusting pad  40  is preferably hinged to a bottom surface of the base  14 , however other commonly known fastening methods such as detents, latches, screws, snaps or hook and loop fasteners can also be used to secure the dusting pad  40  to the base  14 . The dusting pad  40  and brush roll  34  are positioned in a generally parallel fashion with respect to the drive wheels  30 . A removable dusting cloth  42  wraps around, and is held by, the dusting pad  40  as will be described further herein. 
   Referring again to  FIG. 3 , a power source comprising a plurality of batteries  44 , which may be any commonly known battery source including alkaline, rechargeable nickel-cadmium, NiMH, or LiMH are located on base assembly  14 . When rechargeable batteries are used, a commonly known recharging circuit is used to transform available facility voltage to a level usable for the batteries  44 . A charging plug connected to the transformer is manually or automatically attached to a corresponding jack connected to the batteries thereby completing the circuit and allowing the batteries to charge. A commonly known computer processing unit further comprising a logic board  46  is located between the base  14  and the top enclosure  12 . The logic board  46  comprises a commonly known printed circuit board upon which commonly known computer processing and electronic components are mounted configured in a manner similar to that described by U.S. Pat. No. 6,459,955 to Bartsch et al. which is incorporated by reference herein in its entirety. Power from the batteries  44  is controlled by the switch  28 . When switch  28  is on, power flows to the logic board  46 . When the switch  28  is off, no power flows to the logic board  46 . The logic board  46  receives inputs from the various sensors  24 ,  26 ,  38  and provides conditioned output to drive the drive wheels  30  and regulate operation of solution delivery, suction, and brush rotation. One example of such a logic board is that used in the commercially available TALRIK II robot manufactured by Mekatronix which is incorporated herein by reference. 
   Referring to  FIG. 3 , a drive system further comprising a plurality of reversible direct current (DC) drive motors  48  are preferably mounted on an upper surface of the base  14  perpendicular to each of the drive apertures  32 . Alternatively, the drive motors  48  may be mounted on the lower surface of the base  14  or on a separate suspension plate (not shown). The drive motors  48  are directly coupled to the center of each drive wheel  30  such that rotation of the motor results in a corresponding rotation of the drive wheel  30 . Energy to power the drive motors  48  is delivered from the logic board  46  to the drive motors  48  via commonly known wiring (not shown). 
   Referring to  FIG. 2 , a floor condition sensor system comprising a plurality of floor condition sensors  38  are mounted to the bottom surface of the base  14 . Each sensor  38  provides signals relative to the condition of the surface being cleaned to the logic board  46  for processing. The logic board  46 , in turn, processes those signals and provides output to control the action of the fluid distribution system, fluid recovery system, or brush agitation. One such example of a floor condition sensing apparatus is shown in U.S. Pat. No. 6,446,302 to Kasper et al. issued on Sep. 10, 2002 and is hereby incorporated herein by reference in its entirety. 
   Referring to  FIGS. 3 and 4 , a fluid distribution system comprises a clean solution tank  16 , a solution conduit  50 , a solution solenoid valve  52 , and a spray bar  54  or spray tip. Alternatively, the solution system can include a fluid pump to move solution under pressure from the solution tank  16  to the spray bar  54  or a spray tip. The clean solution tank  16  is removably mounted in a tank recess  18  formed within the top enclosure  12 . Solution tank  16  further includes a commonly known, normally closed, removable solution delivery valve (not shown). The delivery valve may be selectively removed to gain access to a solution tank inlet (not shown) filling the solution tank  16  with the necessary water and cleaning solutions. Alternatively, the delivery valve may be fixedly secured to the solution tank  16  and filling may be accomplished through a secondary inlet opening with an associated resealable cap. With the solution tank  16  removed from the top enclosure  12 , a spring forces the delivery valve closed to retain solution within the tank. When the solution tank  16  is inserted into the top enclosure  12 , a nub on a corresponding fitting (not shown) depresses the delivery valve and opens up a path for the solution to flow through. The solenoid valve  52  is electrically operated upon command from the logic board  46  and controls the flow of solution through the solution conduit  50 . The spray bar  54  comprises a hollow chamber creating a manifold that includes a series of apertures along the length of the manifold. In operation, solution is allowed to flow through the manifold by gravitational force to the surface being cleaned. One example of such a gravity feed solution delivery system on an upright extraction cleaner is found in U.S. Pat. No. 6,467,122 to Lenkiewicz et al. and is incorporated herein by reference in its entirety. 
   Again referring to  FIGS. 3 and 4 , a fluid recovery system for withdrawing wet or dry debris from the surface to be cleaned comprises a suction motor  56 , a suction fan  58 , a working air outlet  60 , the recovery tank  20 , a working air inlet  62 , a suction nozzle  64 , and a suction motor exhaust  66 . The suction motor  56  receives power as needed from the logic board  46 . The suction fan  58  is directly coupled to the suction motor  56  and is free to rotate within a fan housing. Rotation of the fan  58  creates a working airflow that lifts and carries debris from the surface as indicated by the arrows in  FIG. 4 . In the preferred embodiment, suction nozzle  64  is in fluid communication with a chamber in which the brush roll  34  resides. Alternatively, suction nozzle  64  may bypass the brush roll  34  and chamber and is located forward of the brush roll  34  is located in close proximity to the surface to be cleaned. In operation, the rotating fan  58  draws air and entrained debris from the suction nozzle  64 , through the working air inlet  62 , and into the recovery tank  20 . Liquid and debris in the working air are separated within the recovery tank  20  due to gravity pulling the debris to the bottom of the tank. Clean working air, free of debris that settled into the recovery tank  20 , moves into the working air outlet  60  into the fan housing, through the fan  58 . The motor exhaust  66  is located on an outer surface of the top enclosure  12  and is in fluid communication with the suction motor  56  and the suction fan  58 . Therefore, working air passing over the suction motor  56  is allowed to exit the enclosure  12  at the motor exhaust  66 . This commonly known fluid recovery system is also described in U.S. Pat. No. 6,467,122. 
   Referring to  FIGS. 2 ,  3  and  4 , an agitation system is described comprising at least one brush roll  34 , a brush roll gear  68 , a belt  70 , and a brush drive source. The brush roll  34  is mounted horizontally within, and protrudes below the suction aperture  36  formed in the base  14 . Furthermore, the suction nozzle  64  is sealing mated to the suction aperture  36 . A pliable squeegee  37  is affixed to a rear edge of the suction aperture  36  and is in contact with the surface being cleaned. The brush roll  34  resides in a cavity formed within the suction aperture  36  and the suction nozzle  64 . The brush roll  34  is preferably a cylindrical dowel with flexible bristles protruding therefrom. Alternatively, the brush roll  34  comprises a plurality of pliable paddles in combination with, or separate from the bristles. An axle runs longitudinally through the center axis of the brush roll  34 . In another embodiment, pair of counter-rotating brush rolls  34  are used in place of the single brush roll  34 . Alternatively, the brush rolls  34  may rotate in the same direction. The brush roll gear  68  is fixedly attached to one of the axles. The axles rotate within commonly known bearings located on both sides of the suction aperture  36 . A belt  70  engages the brush roll gear  68  on one end and is attached to a drive gear on the other. In the preferred embodiment, brush drive is provided by an electric brush motor  72 . Power to the brush motor  72  is supplied by outputs from the logic board  46 . The brush motor  72  is suitably mounted on an upper surface of the base  14  in such a manner that the drive gear on the brush motor  72  is in alignment with the brush roll gear  68 . This commonly known agitation system is also described in U.S. Pat. No. 6,467,122. In an alternate embodiment, the electric brush motor  72  is replaced with an air driven turbine that receives its airflow from the suction fan  58 . In yet another embodiment, the brush motor  72  is eliminated and the drive belt  70  is connected to a shaft protruding from the suction motor  56 . In yet another embodiment, brush drive is accomplished via the drive wheel motor  48  through a secondary gear attached to a protruding shaft. 
   The various components work together to control the robotic extraction cleaner  10  as depicted schematically in  FIG. 5  and shown in plan view in  FIG. 6 . Power is supplied to the logic board  46  through the batteries  44  via the power switch  28 . The proximity sensors  24 ,  26  and the floor condition sensors  38  provide inputs to the logic board  46 . The logic board  46  processes the inputs and selectively sends appropriate output signals to the drive wheels  30 , solution solenoid valve  52 , brush motor  72 , and optionally to the suction motor  56 . 
   The infra-red proximity sensors  24  emit an infra-red light beam that is reflected from surrounding objects and detected by the sensor  24 . The pressure-sensitive proximity sensors  26  are activated by direct contact with a stationary object, closing a conductive path within the sensor  26  and providing a signal to the logic board  46 . The floor condition sensors  38  measure the amount of discoloration in the surface being cleaned and transmits an appropriate signal to the logic board  46 . When activated, the robot extraction cleaner  10  normally moves in a generally straight and forward direction because equal outputs are provided to each drive motor  48 . Output signals to the individual drive motors  48  change as inputs from the various sensors change. For example, when one or more of the proximity sensors  24 ,  26  detect a stationary object, output to a corresponding drive wheel  30  is slowed. Since the drive wheels  30  are now moving at different speeds, the robot extractor turns in the direction of the slower turning wheel. 
   The floor condition sensors  38  measure the relative degree of soil on the surface being cleaned by sensing color variation. As surface color variations are encountered, output to the drive wheels  30  is slowed and possibly stopped depending upon the amount of color variation detected. Output signals are then generated by the logic board  46  and transmit control signals to either the brush motor  72 , the solution solenoid valve  52 , or the suction motor  56 . The robot extractor can then apply solution to the surface and optionally agitate the surface with the brush roll  34  as needed until the condition sensors  38  detect a predetermined level of acceptable color variation. Upon reaching the predetermined level of cleanliness, output signals to the solution solenoid valve  52  and the brush motor  72  cease and drive commands to the drive wheels  30  are resumed to begin movement of the robot extractor on a straight path once again. 
   Referring to  FIGS. 2 ,  7 , and  8 , a dusting assembly is described comprising a dusting pad  40 , a dusting cloth  42 , and a plurality of hinges  74 . The dusting pad  40  further comprises a plurality of engagement members  76  that rest along the bottom surface of the base  14 . The cloth engagement members  76  are made from a resilient material including any number of commonly known plastics and further comprise a plurality of slots  78 . The cloth engagement members  76  are similar to those disclosed in U.S. Pat. No. 6,305,046 to Kingry, specifically in  FIGS. 4 through 7 , which is hereby incorporated by reference herein in its entirety. 
   The dusting pad  40  is attached to the base  14  via the plurality of hinges  74  affixed along a length of one side of the dusting pad  40  and at the rear of the base  14  on the other. A commonly known magnetic latch  80  is affixed to a top surface of the dusting pad  40 . A steel catch  82  is located on the underside of the base  14  such that the catch  82  aligns with the latch  80  when the dusting pad  40  is placed in the closed position as defined by the upper surface of the dusting pad  40  being in direct contact with the lower surface of the base  14 . Magnetic force between the latch  80  and the catch  82  maintains contact between the top of the dusting pad  40  and the bottom of the base  14  during use. To open the dusting pad  40 , the user applies hand force to overcome the magnetic force, allowing the dusting pad  40  to rotate about the hinges  74  which then allows access to the engagement members  76 . Alternatively, the dusting pad  40  is fixedly attached to the bottom surface of the base  14 . The cloth engagement members  76  are accessible from the bottom and the dusting cloth  42  is removed directly from the bottom. 
   The dusting cloth  42  is wrapped around the dusting pad  40  in a longitudinal direction. In the preferred embodiment, the dusting cloth  42  is an electrostatically charged dry cloth that attracts oppositely charged debris particles. In an alternate embodiment, the dusting cloth  42  is a pre-moistened cloth suitable for removing sticky stains. The dusting cloth  42  is attached to the pad  40  by forcing the cloth  42  into the slots  78 , thus providing an easy method of inserting and removing the dusting cloth  42  from the unit as disclosed in FIG. 2 of U.S. Pat. No. 6,305,046 to Kingry. 
   In operation, the user connects the robot extraction cleaner  10  to facility power to energize the charging circuit. Once a full charge on the batteries  44  is achieved, the user removes the charging circuit from the robot extractor cleaner  10  and engages the electrical switch  28 . Power is then delivered to the logic board  46 . The logic board  46  controls output based on input from the proximity sensors  24 ,  26  and the floor condition sensors  38 . The robot extraction cleaner  10  moves across the surface to be cleaned in a random fashion, changing speed and direction as the proximity sensors  24 ,  26  encounter obstructions and as inputs from the floor condition sensors  38  change. The logic board  46  directs the robot extraction cleaner  10  to move in a direction that prefers the suction nozzle  64  in a forward position and the dusting cloth  42  in a rearward position. As such, larger loose debris is removed from the surface before the dusting cloth  42  passes. This sequence allows for longer life of the dusting cloth  42  and improved cleaning of the surface. After use, the user turns the electrical switch  28  to the off position, thus interrupting power to the logic board  46 . The user removes the recovery tank  20  from the top enclosure  12 . Debris from the recovery tank  20  is dumped into an appropriate disposal receptacle. The now dirty dusting cloth  42  is removed from the dusting pad  40  by overcoming the magnetic latch  80 , rotating the dusting pad  40  to the open position, removing the dusting cloth  42 , and similarly properly disposing of the dusting cloth  42 . A new dusting cloth  42  is attached. The recovery tank  20  is reattached to the top enclosure  12 . The robot extraction cleaner  10  is reattached to the charging circuit to replenish power to the batteries  44 , whereby the entire cleaning process may begin again. 
   While the preferred invention has been described as a robotic extraction cleaner, it can also be appreciated that several subsets of the preferred embodiment may be recombined in new and different ways to provide various configurations. Any of the floor condition sensor system, fluid distribution system, fluid recovery system, or agitation system may be used alone or in combination to create an apparatus to solve specific cleaning problems not requiring all the capabilities of all the subsystems herein described. Furthermore, while the invention is described as an extraction system, it may also describe a dry removal system whereby dry debris is withdrawn and deposited in a dirt receptacle or filter bag. 
   While the invention has been specifically described in connection with certain specific embodiments, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the foregoing disclosure and drawings without departing from the spirit of the invention which is set forth in the appended claims.