Patent Publication Number: US-2020281430-A1

Title: Evacuation Station

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This U.S. patent application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application 62/096,771, filed Dec. 24, 2014, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to evacuating debris collected by robotic cleaners. 
     BACKGROUND 
     Autonomous robots are robots which can perform desired tasks in unstructured environments without continuous human guidance. Many kinds of robots are autonomous to some degree. Different robots can be autonomous in different ways. An autonomous robotic cleaner traverses a work surface without continuous human guidance to perform one or more tasks. In the field of home, office, and/or consumer-oriented robotics, mobile robots that perform household functions, such as vacuum cleaning, floor washing, lawn cutting and other such tasks, have become commercially available. 
     SUMMARY 
     A robotic cleaner may autonomously move across a floor surface of an environment to collect debris, such as dirt, dust, and hair, and store the collected debris in a debris bin of the robotic cleaner. The robotic cleaner may dock with an evacuation station to evacuate the collected debris from the debris bin and/or to charge a battery of the robotic cleaner. The evacuation station may include a base that receives the robotic cleaner in a docked position. While in the docked position, the evacuation station interfaces with the debris bin of the robotic cleaner so that the evacuation station can remove debris accumulated within the debris bin. The evacuation station may operate in one of two modes, an evacuation mode and an air filtration mode. During the evacuation mode, the evacuation station removes debris from the debris bin of a docked robotic cleaner. During the air filter filtration, the evacuation station filters air about the evacuation station, regardless of whether the robotic cleaner is docked at the evacuation station. The evacuation station may pass an air flow through a particle filter to remove small particles (e.g., ˜0.1 to ˜0.5 micrometers) before exhausting to the environment. The evacuation station may operate in the air filtration mode when the evacuation is not evacuating debris from the debris bin. For example, the air filtration mode may operate when a canister for collecting debris is not connected to the base, when the robotic cleaner is not docked with the evacuation station, or whenever debris is not being evacuated from the robotic cleaner. 
     One aspect of this disclosure provides an evacuation station including a base and a canister. The base includes a ramp, a first conduit portion of a pneumatic debris intake conduit, an air mover, and a particle filter. The ramp has a receiving surface for receiving and supporting a robotic cleaner having a debris bin. The ramp defines an evacuation intake opening arranged to pneumatically interface with the debris bin of the robotic cleaner when the robotic cleaner is received on the receiving surface in a docked position. The first conduit portion of the pneumatic debris conduit is pneumatically connected to the evacuation intake opening. The air mover has an inlet and an exhaust, with the air mover moving air received from the inlet out the exhaust. The particle filter is pneumatically connected to the exhaust of the air mover. The canister is removably attached to the base and includes a second conduit portion of the pneumatic debris intake conduit, a separator, an exhaust conduit and a collection bin. The second conduit portion is arranged to pneumatically connect to or interface with the first conduit portion to form the pneumatic debris intake conduit (e.g., as a single conduit) when the canister is attached to the base. The separator is in pneumatic communication with the second conduit portion of the debris intake conduit, with the separator separating debris out of a received flow of air. The exhaust conduit is in pneumatic communication with the separator and arranged to pneumatically connect to the inlet of the air mover when the canister is attached to the base. The collection bin is in pneumatic communication with the separator. 
     Implementations of the disclosure may include one or more of the following optional features. In some implementations, the separator defines at least one collision wall and channels arranged to direct the flow of air from the second conduit portion of the pneumatic debris intake conduit toward the at least one collision wall to separate debris out of the flow of air. At least one collision wall may define a separator bin having a substantially cylindrical shape. 
     In some examples, the separator includes an annular filter wall defining an open center region. The annular filter wall is arranged to receive the flow of air from the second conduit portion of the pneumatic debris intake conduit to remove debris out of the flow of air. The separator may include another particle filter filtering larger particles than the other particle filter. The separator may further include a filter bag arranged to receive the flow of air from the second conduit portion of the pneumatic debris intake conduit to remove debris out of the flow of air. 
     In some implementations, the collection bin includes a debris ejection door movable between a closed position for collecting debris in the collection bin and an open position for ejecting collected debris from the collection bin. The canister and the base may have a trapezoidal shaped cross section. The canister and the base may define a height of the evacuation station, the canister defining greater than half of the height of the evacuation station. Additionally or alternatively, the canister defines at least two-thirds of the height of the evacuation station. 
     In some examples, the ramp further includes a seal pneumatically sealing the evacuation intake opening and a collection opening of the robotic cleaner when the robotic cleaner is in the docked position. The ramp may further include one or more charging contacts disposed on the receiving surface and arranged to interface with one or more corresponding electrical contacts of the robotic cleaner when received in the docked position. The ramp may further include one or more alignment features disposed on the receiving surface and arranged to orient the received robotic cleaner so that the evacuation intake opening pneumatically interfaces with the debris bin of the robotic cleaner and the one or more charging contacts electrically connect to the electrical contacts of the robotic cleaner when received in the docked position. Additionally or alternatively, one or more alignment features may include wheel ramps accepting wheels of the robotic cleaner while the robotic cleaner is moving to the docked position and wheel cradles supporting the wheels of the robotic cleaner when the robotic cleaner is in the docked position. 
     The evacuation station may further include a controller in communication with the air mover and the one or more charging contacts. The controller may activate the air mover to move air when the controller receives an indication of electrical connection between the one or more charging contacts and the one or more corresponding electrical contacts. 
     Another aspect of the disclosure includes a base and a canister. The base includes a ramp, a first conduit portion of a pneumatic debris intake conduit, a flow control device, an air mover, and a particle filter. The ramp has a receiving surface for receiving and supporting a robotic cleaner having a debris bin. The ramp defines an evacuation intake opening arranged to pneumatically interface with the debris bin of the robotic cleaner when the robotic cleaner is received on the receiving surface in a docked position. The first conduit portion of the pneumatic debris intake conduit is pneumatically connected to the evacuation intake opening and the flow control device is pneumatically connected to the first conduit portion of the pneumatic debris intake conduit. The air mover has an inlet and an exhaust. The inlet is pneumatically connected to the flow control device. The air mover moves air received from the inlet or the flow control device out the exhaust. The particle filter is pneumatically connected to the exhaust. The canister is removable attached to the base and includes a second conduit portion of the pneumatic debris intake conduit, a separator, an exhaust conduit and a collection bin. The second conduit portion is arranged to pneumatically connect to or interface with the first conduit portion to form the pneumatic debris intake conduit when the canister is attached to the base. The separator is in pneumatic communication with the second conduit portion of the pneumatic debris intake conduit. The separator separates debris out of a received flow of air. The exhaust conduit is in pneumatic communication with the separator and arranged to pneumatically connect to the inlet of the air mover when the canister is attached to the base. The collection bin is in pneumatic communication with the separator. 
     In some implementations, the flow control device moves between a first position that pneumatically connects the exhaust to the inlet of the air mover when the canister is attached to the base and a second position that pneumatically connects an environmental air inlet of the air mover to the exhaust of the air mover. Additionally or alternatively, the flow control device moves to the second position, pneumatically connecting the exhaust to the inlet of the air mover, when the canister is removed from the base. The flow control device may be spring biased toward the first position or the second position. 
     In some examples, the evacuation station further includes a controller in communication with the flow control device and the air mover. The controller executes operation modes including a first operation mode and a second operation mode. During the first operation mode, the controller activates the air mover and actuates the flow control device to move to the first position, pneumatically connecting the exhaust to the inlet of the air mover. During the second operation mode, the controller activates the air mover and actuates the flow control device to the second position, pneumatically connecting the environmental air inlet of the air mover to the exhaust of the air mover. 
     The evacuation station may further include a connection sensor in communication with the controller and sensing connection of the canister to the base. The controller executes the first operation mode when the controller receives a first indication from the connection sensor indicating that the canister is connected to the base. The controller executes the second operation mode when the controller receives a second indication from the connection sensor indicating that the canister is disconnected from the base. 
     The evacuation station may further include one or more charging contacts in communication with the controller, disposed on the receiving surface of the ramp, and arranged to interface with one or more corresponding electrical contacts of the robotic cleaner when received in the docked position. When the controller receives an indication of electrical connection between the one or more charging contacts and the one or more corresponding electrical contacts it executes the first operation mode. Additionally or alternatively, when the controller receives an indication of electrical disconnection between the one or more charging contacts and the one or more corresponding electrical contacts, it executes the second operation mode. 
     In some examples, the ramp further includes one or more alignment features disposed on the receiving surface and is arranged to orient the received robotic cleaner so that the evacuation intake opening pneumatically interfaces with the debris bin of the robotic cleaner and the one or more charging contacts electrically connected to the electrical contacts of the robotic cleaner when received in the docket position. Additionally or alternatively, the one or more alignment features may include wheel ramps accepting wheels of the robotic cleaner while the robotic cleaner is moving to the docked position and wheel cradles supporting the wheels of the robotic cleaner when the robotic cleaner is in the docked position. 
     In some examples, the separator defines at least one collision wall and channels arranged to direct the flow of air from the second conduit portion of the pneumatic debris intake conduit toward the at least one collision wall to separate debris out of the flow of air. At least one collision wall may define a separator bin having a substantially cylindrical shape. 
     In some implementations, the separator includes an annular filter wall defining an open center region. The annular filter wall is arranged to receive the flow of air from the second conduit portion of the pneumatic debris intake conduit to remove the debris out of the flow of air. The separator may include another particle filter filtering larger particles than the other particle filter. The separator may further include a filter bag arranged to receive the flow of air from the second conduit portion of the pneumatic debris intake conduit to remove debris out of the flow of air. In some examples, the collection bin includes a debris ejection door movable between a closed position for collecting debris in the collection bin and an open position for ejecting collected debris from the collection bin. The canister and the base may have a trapezoidal shaped cross section. The canister and the base may define a height of the evacuation station, the canister defining greater than half of the height of the evacuation station. Additionally or alternatively, the canister defines at least two-thirds of the height of the evacuation station. In some examples, the ramp further includes a seal pneumatically sealing the evacuation intake opening and a collection opening of the robotic cleaner when the robotic cleaner is in the docked position. 
     Yet another aspect of the disclosure provides a method that includes receiving, at a computing device, a first indication of whether a robotic cleaner is received on a receiving surface of an evacuation station in a docked position. The method further includes receiving, at the computing device, a second indication of whether a canister of the evacuation station is connected to a base of the evacuation station. When the first indication indicates that the robotic cleaner is received on the receiving surface of the evacuation station in the docked position and the second indication indicates that the canister is connected to the base, the method includes actuating a flow control valve, using the computing device, to move to a first position that pneumatically connects exhaust conduit of the canister or base to an inlet of an air mover of the canister or base and activating, using the computing device, the air mover to draw air into an evacuation intake opening defined by the evacuation station pneumatically interfacing with a debris bin of the robotic cleaner to draw debris from the debris bin of the docked robotic cleaner into the canister. When the first indication indicates that the robotic cleaner is not received on the receiving surface of the evacuation station in the docked position or the second indication indicates that the canister is disconnected from the base, the method includes actuating the flow control valve, using the computing device, to move to a second position that pneumatically connects an environmental air inlet of the air mover to a particle filter and activating, using the computing device, the air mover to draw air into the environmental air inlet and move the drawn air through the particle filter. 
     In some examples, the method includes receiving the first indication including receiving an electrical signal from one or more changing contacts disposed on the receiving surface and arranged to interface with one or more corresponding electrical contacts of the robotic cleaner when the robotic cleaner is received in the docked position. Receiving the second indication includes receiving a signal from a connection sensor sensing connection of the canister to the base. Additionally or alternatively, the connection sensor includes an optical-interrupt sensor, a contact sensor, and/or a switch. 
     In some implementations, the base includes a first conduit portion of a pneumatic debris intake conduit pneumatically connected to the evacuation intake opening. The air mover has an inlet and an exhaust, the inlet is pneumatically connected to the flow control valve and the air mover moves air received from the inlet or the flow control valve out the exhaust. The particle filter is pneumatically connected to the exhaust. 
     In some examples, the canister includes a second conduit portion of the pneumatic debris intake conduit arranged to pneumatically connect to the first conduit portion to form the pneumatic debris intake conduit when the canister is attached to the base. The separator is in pneumatic communication with the second conduit portion, the separator separating debris out of a received flow of air. The exhaust is in pneumatic communication with the separator and arranged to pneumatically connect to the inlet of the air mover when the canister is attached to the base and when the flow control valve is in the first position. The collection bin is in pneumatic communication with the separator. 
     Yet another aspect of the disclosure provides a method that includes receiving a robotic cleaner on a receiving surface. The receiving surface defines an evacuation intake opening arranged to pneumatically interface with a debris bin of the robotic cleaner when the robotic cleaner is received in a docked position. The method includes drawing a flow of air from the debris bin through a pneumatic debris intake conduit using an air mover. The method further includes directing the flow of air to a separator in communication with the pneumatic debris intake conduit. The separator is defined by at least one collision wall and channels arranged to direct the flow of air from the pneumatic debris intake conduit toward the at least one collision wall to separate debris out of the flow of air. The method further includes collecting the debris separated by the separator in a collection bin in communication with the separator. 
     In some implementations, the method further includes receiving a first indication of whether the robotic cleaner is received on the receiving surface in the docked position and receiving a second indication of whether the canister is connected to the base. When the first indication indicates that the robotic cleaner is received on the receiving surface in the docked position and the second indication indicates that the canister is connected to the base, the method further includes drawing the flow of air from the debris bin and directing the flow of air to the separator. 
     The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a perspective view of an example robotic cleaner docked with an evacuation station. 
         FIG. 2A  is top view of an example robotic cleaner. 
         FIG. 2B  is a bottom view of an example robotic cleaner. 
         FIG. 3  is a perspective view of an example ramp and base of an evacuation station. 
         FIG. 4  is a perspective view of an example base of an evacuation station. 
         FIG. 5  is a schematic view of an example base of an evacuation station. 
         FIG. 6  is a schematic view of an example canister of an evacuation station enclosing a filter. 
         FIG. 7  is a schematic view of an example canister of an evacuation station enclosing an air particle separator device. 
         FIG. 8A  is a schematic top view of an example canister of an evacuation station enclosing a filter and an air particle separator device. 
         FIG. 8B  is a schematic side view of an example canister of an evacuation station enclosing a filter and an air particle separator device. 
         FIG. 9A  is a schematic top view of an example canister of an evacuation station enclosing a two-stage air separator device. 
         FIG. 9B  is a schematic side view of an example canister of an evacuation station enclosing a two-stage air separator device. 
         FIG. 10A  is a schematic top view of an example canister of an evacuation station enclosing a filter bag. 
         FIG. 10B  is a schematic side view of an example canister of an evacuation station enclosing a filter bag. 
         FIG. 11  is a schematic view of an example evacuation station. 
         FIGS. 12A and 12B  are schematic views of an example flow control device for directing air flow through an air filter. 
         FIG. 13  is schematic view of an example controller of an evacuation station. 
         FIG. 14  is an example method for operating an evacuation station in first and second operation modes. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-5 , in some implementations, an evacuation station  100  for evacuating debris collected by a robotic cleaner  10  includes a base  120  and a canister  110  removably attached to the base  120 . The base  120  includes a ramp  130  having a receiving surface  132  ( FIG. 3 ) for receiving and supporting a robotic cleaner  10  having a debris bin  50 . As shown in  FIG. 3 , the ramp  130  defines an evacuation intake opening  200  arranged to pneumatically interface with the debris bin  50  of the robotic cleaner  10  when robotic cleaner  10  is received on the receiving surface  132  in a docked position. The docked position refers to the receiving surface  132  in contact with and supporting wheels  22   a ,  22   b  of the robotic cleaner  10 . In some implementations, the ramp  130  is included at an angle, θ. When the robotic cleaner  10  is in the docked position, the evacuation station  100  may remove debris from the debris bin  50  of the robotic cleaner  10 . In some implementations, the evacuation station  100  charges one or more energy storage devices (e.g., a battery  24 ) of the robotic cleaner  10  while in the docked position. In some examples, the evacuation station  100  simultaneously removes debris from the bin  50  while charging the battery  24  of the robot  10 . 
     A lower portion  128  of the base  120  proximate to the ramp  130  may include a profile having a radius configured to permit the robot  10  to be received and supported upon the ramp  130 . External surfaces of the canister  110  and the base  120  may be defined by front and back walls  112 ,  114  and first and second side walls  116 ,  118 . In some examples, the walls  112 ,  114 ,  116 ,  118  define a trapezoidal shaped cross section of the canister  110  and the base  120  to enable the back wall  114  of the canister  110  and the base  120  to unobtrusively abut and rest flush against a wall in the environment. When the walls  112 ,  114 ,  116 ,  118  define the trapezoidal shaped cross section, the back wall  114  may include a width (i.e., distance between the side walls  116  and  118 ) greater than a width of the front wall  112 . In other examples, the cross section of the canister  110  and the base  120  may be polygonal, rectangular, circular, elliptical or some other shape. 
     In some examples, the base  120  and the ramp  130  of the evacuation station  100  are integral, while the canister  110  is removably attached to the base  120  (e.g., via one or more latches  124 , as shown in  FIG. 4 ) to collect debris drawn from the debris bin  50  when the robot  10  is in the docked position at the evacuation station  100 . In some examples, the one or more latches  124  releasably engage with corresponding spring-loaded detents  125  ( FIG. 6 ) located on the canister  110 . The canister  110  and the base  120  together define a height H of the evacuation station  100 . In some examples, the canister  110  includes greater than half of the defined height H. In other examples, the canister  110  includes at least two-thirds of the defined height H. The canister  110  may attach to the base  120  when a user applies sufficient force, causing features located on the canister  110  to engage with the latches  124  disposed on the base  120 . A connection sensor  420  ( FIG. 4 ) may communicate with a controller  1300  (e.g., computing device) and sense connection of the canister  110  to the base  120 . In some examples, the connection sensor  420  includes a contact sensor (e.g., a switch or a capacitive sensor) sensing whether or not a mechanical connection exists between the one or more latches  124  and corresponding spring-loaded detents  125  located on the canister  110 . In other examples, the connection sensor  420  includes an optical sensor (e.g., photointerrupter/phototransistor or infrared proximity sensor) sensing whether or not the canister  110  is connected to the base  120 . The canister  110  may be removed or detached from the base  120  when a user pulls the canister  110  away from the base  120  releasing the latches  124 . The canister  110  may include a handle  102  for a user to grip to transport the canister  110 . In some examples, the canister  110  detaches from the base  120  when a user pulls upward on the handle  102 . In some examples, the canister  110  includes an actuator button  102   c  for releasing the latches  124  of the base  120  from the corresponding spring-loaded detents  125  located on the canister  110  when the user depresses the actuator button  102   c.    
     In some implementations, the canister  110  includes a debris ejection door button  102   a  for opening a debris ejection door  662  ( FIG. 6 ) when a user presses the button  102   a  to empty debris into a trash receptacle when the canister  110  is full. In some implementations, the canister  110  includes a filter access door button  102   b  for opening a filter access door  104  of the canister  110  when the button  102   b  depresses to access a filter  650  ( FIG. 6 ) or filter bag  1050  ( FIG. 10 ) for inspection, servicing, and/or replacement. Ergonomically, the buttons  102   a ,  102   b ,  102   c  may be located on or proximate to the handle  102 . 
     The evacuation station  100  may be powered by an external power source  192  via a power cord  190 . For example, the external power source  192  may include a wall outlet, delivering an alternating current (AC) via the power cord  190  for powering an air mover  126  ( FIG. 5 ) that causes debris to be pulled from the debris bin  50  of the robotic cleaner  10 . The evacuation station  100  may include a DC converter  1790  ( FIG. 17 ) for powering the controller  1300  of the evacuation station  100 . 
     In some implementations, the controller  1300  receives signals and executes algorithms to determine whether or not the robotic cleaner  10  is in the docked position at the evacuation station  100 . For example, the controller  1300  may detect the location of the robot  10  in relation to the evacuation station  100  (via one or more sensors, such as proximity and/or contact sensors) to determine whether the robotic cleaner  10  is in the docked position. The controller  1300  may operate the evacuation station  100  in an evacuation mode (e.g., first operation mode) to suck and collect debris from the debris bin  50  of the robotic cleaner  10 . When the robotic cleaner  10  is not in the docked position or the evacuation station  100  is not operating in the evacuation mode while the robotic cleaner  10  is in the docked position, the controller  1300  may operate the evacuation station  100  in an air filtration mode (e.g., second operation mode). During the air filtration mode, environmental air is drawn by the air mover  126  into the base  120  of the evacuation station  100  and filtered before being released to the environment. For instance, during the evacuation mode, environmental air may be drawn by the air mover  126  through an inlet  298  ( FIG. 5 ) of the base  120  and filtered by a particle filter  302  ( FIG. 5 ) within the base  120  and out an exhaust  300 . The base  120  may further include a user interface  150  in communication with the controller  1300  for allowing the user to input signals for execution by the evacuation station and for displaying operation and functionality of the evacuation station  100 . For example, the user interface  150  may display a current capacity of the canister  110 , a remaining time for the debris bin  50  to be evacuated, a remaining time for the robot  10  to be charged, a confirmation of the robot  10  being docked, or any other pertinent parameter. In some examples, the user interface  150  and/or controller  1300  are located on the front wall  112  of the canister  110  for improved accessibility and visibility. 
       FIGS. 2A and 2B  illustrate an exemplary autonomous robotic cleaner  10  (also referred to as a robot) for docking with the evacuation station; however, other types of robotic cleaners are possible as well, with different components and/or different arrangements of components. In some implementations, the autonomous robotic cleaner  10  includes a chassis  30  which carries an outer shell  6 .  FIG. 2A  shows the outer shell  6  of the robot  10  connected to a front bumper  5 . The robot  10  may move in forward and reverse drive directions; consequentially, the chassis  30  has corresponding forward and back ends  30   a ,  30   b , respectively. The forward end  30   a  is fore in the direction of primary mobility and the direction of the bumper  5 . The robot  10  typically moves in the reverse direction primarily during escape, bounces, and obstacle avoidance. A collection opening  40  is located toward the middle of the robot  10  and installed within the chassis  30 . The collection opening  40  includes a first debris extractor  42  and a parallel second debris extractor  44 . In some examples, the first debris extractor  42  and/or the parallel second debris extractor  44  is/are removable. In other examples, the collection opening  40  includes a fixed first debris extractor  42  and/or a parallel second debris extractor  44 , where fixed refers to an extractor installed on and coupled to the chassis  30 , yet removable for routine maintenance. In some implementations, the debris extractors  42  and  44  are composed of rubber and include flaps or vanes for collecting debris from the cleaning surface. In some examples, the debris extractors  42  and/or  44  are brushes that may be a pliable multi-vane beater or have pliable beater flaps between rows of brush bristles. 
     The battery  24  may be housed within the chassis  30  proximate the collection opening  40 . Electrical contacts  25  are electrically connected to the battery  24  for providing charging current and/or voltage to the battery  24  when the robot  10  is in the docked position and is undergoing a charging event. For example, the electrical contacts  25  may contact associated charging contacts  252  ( FIG. 3 ) located on the ramp  130  of the evacuation station  100 . 
     Installed along either side of the chassis  30  are differentially driven left and right wheels  22   a ,  22   b  that mobilize the robot  10  and provide two points of support. The forward end  30   a  of the chassis  30  includes a caster wheel  20  which provides additional support for the robot  10  as a third point of contact with the floor (cleaning surface) and does not hinder robot mobility. The removable debris bin  50  is located toward the back end  30   b  of the robot  10  and installed within or forms part of the outer shell  6 . 
     In some implementations, as shown in  FIG. 2A  the robot  10  includes a display  8  and control panel  12  located upon the outer shell  6 . The display  8  may display an operational mode of the robot  10 , debris capacity of the debris bin  50 , state of charge of the battery  24 , remaining life of the battery  24 , or any other parameters. The control panel  12  may receive inputs from a user to turn on/off the robot  10 , schedule charging events for the battery  24 , select evacuation parameters for evacuating the debris bin  50  at the evacuation station  100 , or select a mode of operation for the robot  10 . The control panel  12  may be in communication with a microprocessor  14  that executes one or more algorithms (e.g., cleaning routines) based upon the user inputs to the control panel  12 . 
     Referring again to  FIG. 2B , the bin  50  may include a bin-full detection system  250  for sensing an amount of debris present in the bin  50 . The bin-full detection system  250  includes an emitter  252  and a detector  254  housed in the bin  50 . The emitter  252  transmits light and the detector  254  receives reflected light. In some implementations, the bin  50  includes a microprocessor  54 , which may be connected to the emitter  252  and the detector  254 , respectively, to execute an algorithm to determine whether the bin  50  is full. The microprocessor  54  may communicate with the battery  24  and the microprocessor  14  of the robot  10 . The microprocessor  54  may communicate with the robotic cleaner  10  from a bin serial port  56  to a robot serial port  16 . The robot serial port  16  may be in communication with the microprocessor  14 . The serial ports  16 ,  56  may be, for example, mechanical terminals or optical devices. For instance, the microprocessor  54  may report bin full events to the microprocessor  14  of the robotic cleaner  10 . Likewise, the microprocessors  14 ,  54  may communicate with the controller  1300  to report signals when the robotic cleaner  10  has docked at the ramp  130  of the evacuation station  100 . 
     Referring to  FIG. 3 , the ramp  130  of the evacuation station  100  may include a receiving surface  132  (having an inclination angle θ with respect to the supporting ground surface) selected for facilitating access to and removal of debris residing in the debris bin  50 . The inclination angle θ may also cause debris residing in the debris bin  50  to gather at the back of the bin  50  (due to gravity) when the robot  10  is received in the docked position. In the example shown, the robot  10  docks with the forward end  30   a  facing the evacuation station  100 ; however other docking orientations or poses are possible as well. In some examples, the ramp  130  includes one or more charging contacts  252  disposed on the receiving surface  132  and arranged to interface with one or more corresponding electrical contacts  25  of the robotic cleaner  10  when received in the docked position. In some examples, the controller  1300  determines the robot  10  is in the docked position when the controller receives a signal indicating the charging contacts  252  are connected to the electrical contacts  25  of the robot  10 . The charging contacts  252  may include pins, strips, plates, or other elements sufficient for conducting electrical charge. In some examples, the charging contacts  252  may guide the robotic cleaner  10  (e.g., indicate when the robotic cleaner  10  is docked). 
     In some implementations, the ramp  130  includes one or more guide alignment features  240   a - d  disposed on the receiving surface  132  and arranged to orient the received robotic cleaner so that the evacuation intake opening  200  pneumatically interfaces with the debris bin  50  of the robotic cleaner  10 . The guide alignment features  240   a - d  may additionally be arranged to orient the received robotic cleaner so the one or more charging contacts  252  electrically connect to the electrical contacts  25  of the robotic cleaner  10 . In some examples, the ramp  130  includes wheel ramps  220   a ,  220   b  accepting wheels  22   a ,  22   b  of the robotic cleaner  10  while the robotic cleaner  10  is moving to the docked position. For example, a left wheel ramp  220   a  accepts the left wheel  22   a  of the robot  10  and a right wheel ramp  220   b  accepts the right wheel  22   b  of the robot  10 . Each wheel ramp  220   a ,  220   b  may include an inclined surface and a pair of corresponding side walls defining a width of each wheel ramp  220   a ,  220   b  for retaining and aligning the wheels  22   a ,  22   b  of the robotic cleaner  10  upon the wheel ramps  220   a ,  220   b . Accordingly, the wheel ramps  220   a ,  220   b  may include a width slightly greater than a width of the wheels  22   a ,  22   b  and may include one or more traction features for reducing slippage between the wheels  22   a ,  22   b  of the robotic cleaner  10  and the wheel ramps  220   a ,  220   b  when the robotic cleaner  10  is moving to the docked position. In some examples, the wheel ramps  220   a ,  220   b  further function as guide alignment features for aligning the robot  10  when docking on the ramp  130 . 
     In some examples, the one or more guide alignment features include wheel cradles  230   a ,  230   b  supporting the wheels  22   a ,  22   b  of the robotic cleaner  10  when the robotic cleaner  10  is in the docked position. The wheel cradles  230   a ,  230   b  serve to support and stabilize the wheels  22   a ,  22   b  when the robotic cleaner  10  is in the docked position. In the example shown, the wheel cradles  230   a ,  230   b  include U-shaped depressions upon the ramp  130  having radii large enough to accept and retain the wheels  22   a ,  22   b  after the wheels  22   a ,  22   b  traverse the wheel ramps  220   a ,  220   b . In some examples, the wheel cradles  230   a ,  230   b  are rectangular shaped, V-shaped or other shaped depressions. Surfaces of the wheel cradles  230   a ,  230   b  may include a texture permitting slippage of the wheels  22   a ,  22   b  such that the wheels  22   a ,  22   b  can be rotationally aligned when at least one of the wheel cradles  230   a ,  230   b  accepts a corresponding wheel  22   a ,  22   b . The cradles  230   a ,  230   b  may include sensors (or features)  232   a ,  232   b , respectively, indicating when the robotic cleaner  10  is in the docked position. The cradle sensors  232   a ,  232   b  may communicate with the controller  1300 ,  14  and/or  56  to determine when evacuation and/or charging events can occur. In some examples, the cradle sensors  232   a ,  232   b  include weight sensors that measure a weight of the robotic cleaner  10  when received in the docked position. The features  232   a ,  232   b  may include biasing features that depress when the wheels  22   a ,  22   b  of the robot  10  are received by the cradles  230   a ,  230   b , causing a signal to be transmitted to the controller  1300 ,  14  and/or  54  that indicates the robot  10  is in the docked position. 
     In the example shown in  FIG. 3 , the evacuation intake opening  200  is arranged to interface with the collection opening  40  of the robotic cleaner  10 . For example, the evacuation intake opening  200  is arranged to pneumatically interface with the debris bin  50  via the collection opening  40  so that an air flow caused by the air mover  126  draws the debris out of the debris bin  50  and through the collection and evacuation intake openings  40 ,  200 , respectively, to a first conduit portion  202   a  of a pneumatic debris intake conduit  202  ( FIG. 5 ) of the evacuation station  100 . In some implementations, the ramp  130  also includes a seal  204  pneumatically sealing the evacuation intake opening  200  and the collection opening  40  of the robotic cleaner  10  when the robotic cleaner  10  is in the docked position. The drawn flow of air may or may not cause the primary and parallel secondary debris extractors  42 ,  44 , respectively, to rotate as the debris are drawn through the collection opening  40  of the robotic cleaner  10  and into the evacuation intake opening  200  of the ramp  130 . 
     Referring to  FIGS. 4 and 5 , in some implementations, the base  120  includes the air mover  126  having the inlet  298  and the exhaust  300 . The air mover moves air received from the inlet out the exhaust  300 . The air mover  126  may include a motor and fan or impeller assembly  326  for powering the air mover  126 . In some implementations, the base  120  houses a particle filter  302  pneumatically connected to the exhaust  300  of the air mover  126 . The particle filter  302  removes small particles (e.g., between about 0.1 and about 0.5 micrometers) from air received at the inlet  298  and out the exhaust  300  of the air mover  126 . The particle filter  302  may also remove small particles (e.g., between 0.1 and about 0.5 micrometers) from environmental air received at an environmental air inlet  1230  of the air mover  126  and out the exhaust  300  of the air mover  126 . In some examples, the particle filter  302  is a high-efficiency particulate air (HEPA) filter. The particle filter  302  may also be referred to as the HEPA filter and/or an air filter. The particle filter  302  is disposable in some examples, and in other examples, the particle filter is washable to remove any small particles collected thereon. 
     As shown in  FIG. 5 , the base  120  encloses the air mover  126  to draw a flow of air (e.g., air-debris flow  402 ) from the debris bin  50  when the robotic cleaner  10  is in the docked position and the canister  110  is attached to the base  120 . The first conduit portion  202   a  of the pneumatic debris intake conduit  202  transmits the air-debris flow  402  containing debris from the debris bin  50  to a second conduit portion  202   b  of the pneumatic debris intake conduit  202  enclosed within the canister  110 . The second conduit portion  202   b  is arranged to pneumatically interface with the first conduit portion  202   a  to form the pneumatic debris intake conduit  202  when the canister  110  is attached to the base  120 . Accordingly, the pneumatic debris intake conduit  202  corresponds to a single, pneumatic conduit for transporting the air-debris flow  402  that includes an air flow containing the debris drawn from the debris bin  50  of the robotic cleaner  10  through the collection and evacuation intake openings  40 ,  200 , respectively. 
     Referring to  FIG. 6 , the canister  110  includes the second conduit portion  202   b  arranged to pneumatically interface with the first conduit portion  202   a  to form the pneumatic debris intake conduit  202  when the canister  110  is attached to the base  120 . In some implementations, the canister  110  includes an annular filter wall  650  in pneumatic communication with the second conduit portion  202   b . The filter wall  650  may be corrugated to offer relatively greater surface area than a smooth circular wall. In some examples, the annular filter wall  650  is enclosed by a pre-filter cage  640  within the canister  110 . The annular filter wall  650  defines an open center region  655  enclosed by an outer wall region  652 . Accordingly, the annular filter wall  650  includes an annular ring-shaped cross section. The annular filter wall  650  corresponds to a separator that separates and/or filters debris out of the air-debris flow  402  received from the pneumatic debris intake conduit  202 . For example, the air mover  126  draws the air-debris flow  402  through the pneumatic debris intake conduit  202  and the annular filter wall  650  is arranged within the canister  110  to receive the air-debris flow  402  exiting the pneumatic debris intake conduit  202  at the second conduit portion  202   b . In the example shown, the annular filter wall  650  collects debris from the air-debris flow  402  received from the pneumatic debris intake conduit  202 , permitting the debris-free air flow  602  to travel through the open center region  655  to the exhaust conduit  304  arranged to pneumatically connect to the inlet  298  of the air mover  126  when the canister  110  attaches to the base  120 . In some examples, the HEPA filter  302  removes any small particles (e.g., ˜0.1 to ˜0.5 micrometers) prior to the air exiting out to the environment at the exhaust  300 . A portion of the debris collected by the annular filter wall  650  may be embedded upon the filter wall  650  while another portion of the debris may fall into a debris collection bin  660  within the canister  110 . 
     The air-debris flow  402  may be at least partially restricted from freely passing through the outer wall region  652  of the annular filter wall  650  to the open center region  655  when debris embedded upon the filter wall  650  increases. Maintenance may be performed periodically to dislodge debris from the filter wall  650  or to replace the filter wall  650  after extended use. In some examples, the annular filter wall  650  may be accessed by opening the filter access door  104  to inspect and/or replace the annular filter wall  650  as needed. For instance, the filter access door  104  may open by depressing the filter access door button  102   b  located proximate the handle  102 . 
     The debris collection bin  660  defines a volumetric space for storing accumulated debris that falls by gravity after the annular filter wall  650  separates the debris from the air-debris flow  304 . As the debris collection bin  660  becomes full of debris indicating a canister full condition, the flow of air (e.g., the air-debris flow  402  and/or the debris-free air flow  602 ) within the canister  110  may be restricted from flowing freely. In some implementations, one or more capacity sensors  170  located within the collection bin  660  or the exhaust conduit  304  are utilized to detect the canister full condition, indicating that debris should be emptied from the canister  110 . In some examples, the capacity sensors  170  include light emitters/detectors arranged to detect when the debris has accumulated to a threshold level within the debris collection bin  660  indicative of the canister full condition. As the debris accumulates within the debris collection bin  660  and reaches the canister full condition, the debris at least partially blocks the air flow causing a pressure drop within the canister  110  and velocity of the flow of air to decrease. In some examples, the capacity sensors  170  include pressure sensors to monitor pressure within the canister  110  and detect the canister full condition when a threshold pressure drop occurs. In some examples, the capacity sensors  170  include velocity sensors to monitor air flow velocity within the canister  110  and detect the canister full condition when the air flow velocity falls below a threshold velocity. In other examples, the capacity sensors  170  are ultrasonic sensors whose signal changes according to the increase in density of debris within the canister so that a bin full signal only issues when the debris is compacted in the bin. This prevents light, fluffy debris stretching from top to bottom from triggering a bin full condition when much more volume is available for debris collection within the canister  110 . In some implementations, the ultrasonic capacity sensors  170  are located between the vertical middle and top of the canister  110  rather than along the lower half of the canister so the signal received is not affected by debris compacting in the bottom of the canister  110 . When the debris collection bin  660  is full (e.g., the canister full condition is detected), the canister  110  may be removed from the base  120  and the debris ejection door  662  may be opened to empty the debris into a trash receptacle. In some examples, the debris ejection door  662  opens when the debris ejection door button  102   a  proximate the handle  102  is depressed, causing the debris ejection door  662  to swing about hinges  664  to permit the debris to empty. This one button press debris ejection technique allows a user to empty the canister  110  into a trash receptacle without having to touch the debris or any dirty surface of the canister  110  to open or close the debris ejection door  662 . 
     Referring to  FIGS. 7-9B , in some implementations, the canister  110  encloses an air particle separator device  750  (also referred to as a separator) defining at least one collision wall  756   a - h  and channels arranged to direct the air-debris flow  402  received from the pneumatic debris intake conduit  202  toward the at least one collision wall  756   a - d  to separate debris out of the air-debris flow  402 .  FIG. 7  illustrates an example air particle separator device  750   a  including collision walls  756   a - b  defining a first-stage channel  752  and collision walls  756   c - d  defining a second-stage channel  754 . In the example shown, the first-stage channel  752  receives the air-debris flow  402  from the second conduit portion  202   b  of the pneumatic debris intake conduit  202  and directs the flow  402  by centrifugal force toward collision walls  756   a - b  of the channel  752 , causing coarse debris to separate and collect within a collection bin  760 . The flow of air from the first-stage channel  752  is received by the second-stage channel  754 . The second-stage channel  754  directs the flow  402  upward toward collision walls  756   c - d  defining the channel  754 , causing fine debris to separate and collect within the collection bin  760 . The air mover  126  draws the debris-free air flow  602  through the exhaust conduit  304  and to the inlet  298  and out the exhaust  300 . In some examples, small particles (e.g., ˜0.1 to ˜0.5 micrometers) within the debris-free air flow  602  are removed by the HEPA filter  302  prior to exiting out the exhaust  300  to the environment. 
     Referring to  FIGS. 8A and 8B , in some implementations, the canister  110  encloses an annular filter wall  860  in pneumatic communication with an air-particle separator device  750   b  for filtering and separating debris from the air-debris flow  402  received from the pneumatic debris intake conduit  202  during two stages of particle separation.  FIG. 8A  illustrates a top view of the canister  110 , while  FIG. 8B  illustrates a front view of the canister  110 . In the example shown, the canister  110  includes a trapezoidal cross section allowing the canister  110  to rest flush against a wall in the environment to aesthetically enhance the appearance of the evacuation station  100 ; however, the canister  110  may be cylindrical with a circular cross section without limitation in other examples. Internal walls of the canister  110  and/or air-particle separator device  750   b  may include ribs  858  for directing air flow. For example, ribs may be disposed upon interior walls of the canister  110  in an orientation that directs debris separated by the filter  860  and/or air-particle separator device  750   b  to fall away from the exhaust conduit  304  to prevent debris from being received by the inlet  298  of the air mover  126  and clogging the HEPA filter  302 . The air flow through the exhaust  300  may be restricted if the HEPA filter  302  becomes clogged with debris. The filter  860  may include the annular filter wall  650  defining the open center region  655 , as described above with reference to  FIG. 6 . The air-particle separator device  750   b  may include collision walls  756   e - f  defining a separator bin  852  in pneumatic communication with the open center region of the filter  860  and one or more conical separators  854 . 
     In the example shown, the combination of the annular filter wall  860  and the air-particle separator device  750   b  provides debris to be removed from the air-debris flow  402  during two-stages of air particle separation. During the first stage, the filter  860  is arranged to receive the air-debris flow  402  from the pneumatic debris intake conduit  202 . The filter  860  separates and collects coarse debris from the received air-debris flow  402 . The coarse debris removed by the filter  860  may accumulate within a coarse debris collection bin  862  and/or embed upon the filter  860 . Subsequently, the second stage of debris removal commences when the air passes through the filter  860  wall and into the separator bin  852  defined by collision wall  756   e . The air entering the separator bin  852  may be referred to as a second-stage air flow  802 . In the example shown, three conical separators  854  are enclosed within the separator bin  852 ; however, the air-particle separator device  750   b  may include any number of conical separators  854 . Each conical separator  854  includes an inlet  856  for receiving the second-stage air flow  802  within the separator bin  852 . The conical separators  854  include collision walls  756   f  that angle toward each other to create a funnel (e.g., channel) that causes centrifugal force acting upon the second-stage air flow  802  to increase. The increasing centrifugal force causes the second-stage air flow  802  to spin the debris toward collision walls  756   f  of the conical separators  854 , causing fine debris (e.g., dust) to separate and collect within a fine debris collection bin  864 . When the collection bins  862 ,  864  are full, the canister  110  may be removed from the base  120  and the debris ejection door  662  may be opened to empty the debris into a trash receptacle. In some examples, a user may open the debris ejection door  662  by depressing the debris ejection door button  102   a  proximate the handle  102 , causing the debris ejection door  662  to swing about hinges  664  to permit the debris to empty from the collection bins  862  and  864 . This one button press debris ejection technique allows a user to empty the canister  110  into a trash receptacle without having to touch the debris or any dirty surface of the canister  110  to open or close the debris ejection door  662 . The air mover  126  draws the debris-free air flow  602  from the canister  110  via the exhaust conduit  304  to the inlet  298  and out the exhaust  300 . In some examples, small particles (e.g., 0.1 to 0.5 micrometers) within the debris-free air flow  602  are removed by the HEPA filter  302  prior to exiting out the exhaust  300  to the environment. 
     In some examples, coarse and fine debris are separated during two stages of air particle separation using an air-particle separator device  750   c  ( FIGS. 9A and 9B ) without the use of the filter  860  (shown in  FIGS. 8A and 8B ). Referring to  FIGS. 9A and 9B , the air-particle separator device  750   c  is arranged in the canister  110  to receive the air-debris flow  402  from the pneumatic debris intake conduit  202 .  FIG. 9A  illustrates a top view of the canister  110 , while  FIG. 9B  illustrates a front view of the canister  110 . In the example shown, the canister  110  includes a trapezoidal cross section allowing the canister  110  to rest flush against a wall in the environment to aesthetically enhance the appearance of the evacuation station  100 ; however, the canister  110  may include a rectangular, polygonal, circular, or other cross section without limitation in other examples. Ribs  958  may be included upon interior walls of the canister  110  and/or air-particle separator device  750   c  to facilitate air flow. For example, ribs  958  may be disposed upon interior walls of the canister  110  and/or air-particle separator device  750   c  in an orientation that directs debris separated by the air-particle separator device  750   c  to fall away from the exhaust conduit  304  to prevent debris from being received by the inlet  298  of the air mover  126  and clogging the HEPA filter  302 . The air flow through the exhaust  300  may be restricted if the HEPA filter  302  becomes clogged with debris. 
     The air-particle separator device  750   c  includes one or more collision walls  756   g - h  defining a first-stage separator bin  952  and one or more conical separators  954 . In the example shown, the separator bin  952  includes a substantially cylindrical shape having a circular cross section. In other examples, the separator bin  952  includes a rectangular, polygonal, or other cross section. During the first stage of air particle separation, the first-stage separator bin  952  receives the air-debris flow  402  from the pneumatic debris intake conduit  202 , wherein the separator bin  952  is arranged to channel the air-debris flow  402  toward the collision wall  756   g , causing coarse debris to separate and collect within a coarse collection bin  962 . The conical separators  954 , in pneumatic communication with the separator bin  952 , receive a second-stage air flow  902  referring to an air flow with coarse debris being removed at associated inlets  956 . In the example shown, three conical separators  954  are enclosed within the first-stage separator bin  952 ; however, the air-particle separator device  750   c  may include any number of conical separators  954 . The conical separators  954  include collision walls  756   h  that angle toward each other to create a funnel that causes centrifugal force acting upon the second-stage air flow  902  to increase. The increasing centrifugal force directs the second-stage air flow  902  toward the one or more collision walls  756   h , causing fine debris (e.g., dust) to separate and accumulate within a fine debris collection bin  964 . When the collection bins  962 ,  964  are full, the canister  110  may be removed from the base  120  and the debris ejection door  662  may be opened to empty the debris into a trash receptacle. In some examples, a user may open the debris ejection door  662  by depressing the debris ejection door button  102   a  proximate the handle  102 , causing the debris ejection door  662  to swing about hinges  664  to permit the debris to empty from the collection bins  962  and  964 . The air mover  126  draws the debris-free air flow  602  from the canister  110  via the exhaust conduit  304  to the inlet  298  and out the exhaust  300 . In some examples, small particles (e.g., 0.1 to 0.5 micrometers) within the debris-free air flow  602  are removed by the HEPA filter  302  prior to exiting out the exhaust  300  to the environment. 
     Referring to  FIGS. 10A and 10B , in some implementations, the canister  110  includes a filter bag  1050  arranged to receive the air-debris flow  402  from the pneumatic debris intake conduit  202 . The filter bag  1050  corresponds to a separator that separates and filters debris out of the air-debris flow  402  received from the pneumatic debris intake conduit  202 . The filter bag  1050  can be disposable and formed of paper or fabric that allows air to pass through but traps dirt and debris.  FIG. 10A  shows a top view of the canister  110 , and  FIG. 10B  shows a side view of the canister  110 . The filter bag  1050 , while collecting debris via filtration, is porous to permit a debris-free air flow  602  to exit the filter bag  1050  via the exhaust conduit  304 . Accordingly, the debris-free air flow  602  is received by the inlet  298  of the air mover  126  and out the exhaust  300 . In some examples, small particles (˜0.1 to ˜0.5 micrometers) within the debris-free air flow  602  are removed by the HEPA filter  302  ( FIG. 5 ) disposed in the base  120  prior to exiting out the exhaust  300  ( FIG. 5 ). 
     The filter bag  1050  may include an inlet opening  1052  for receiving the air-debris flow  402  from the pneumatic debris intake conduit  202  exiting from the second conduit portion  202   b . A fitting  1054  may be used to attach the inlet opening  1052  of the filter bag  1050  to an outlet of the second conduit portion  202   b  of the pneumatic air-debris intake conduit  202 . In some implementations, the fitting  1054  includes features that poka-yoke mating the filter bag  1050  so that the bag only mates to the fitting  1054  in a proper orientation for use and expansion within the canister  110 . The filter bag  1050  includes a matching interface with features accommodating those on the fitting  1054 . In some examples, the filter bag  1050  is disposable, requiring replacement when the filter bag  1050  becomes full. In other examples, the filter bag  1050  may be removed from the canister  110  and collected debris may be emptied from the filter bag  1050 . 
     The filter bag  1050  may be accessed for inspection, maintenance and/or replacement by opening the filter access door  104 . For example, the filter access door  104  swings about hinges  1004 . In some examples, the filter access door  104  is opened by depressing the filter access door button  102   b  located proximate the handle  102 . The filter bag  1050  may provide varying degrees of filtration (e.g., ˜0.1 microns to ˜1 microns). In some examples, the filter bag  1050  includes HEPA filtration in addition to, or instead of, the HEPA filter  302  located proximate the exhaust  300  within the base  120  of the evacuation station  100 . 
     In some implementations, the canister  110  includes a filter bag detection device  1070  configured to detect whether or not the filter bag  1050  is present. For example, the filter bag detection device  1070  may include light emitters and detectors configured to detect the presence of the filter bag  1050 . The filter bag detection device  1070  may relay signals to the controller  1300 . In some examples, when the filter bag detection device  1070  detects the filter bag  1050  is not within the canister  110 , the filter detection device  1070  prevents the filter access door  104  from closing. For example, the controller  1300  may activate mechanical features or latches proximate the canister  110  and/or filter access door  104  to prevent the filter access door  104  from closing. In other examples, the filter bag detection device  1070  is mechanical and movable between a first position for preventing the filter access door  104  from closing and a second position for allowing the filter access door  104  to close. In some examples, a fitting  1054  swings or moves upward when the filter bag  1050  is removed and prevents the filter door  104  from closing. The fitting  1054  is depressed upon insertion of the filter bag  1050  allowing the filter door  104  to close. In some examples, detecting when the filter bag  1050  is not present in the canister  110  prevents the evacuation station  100  from operating in the evacuation mode, even if the robotic cleaner  10  is received at the ramp  130  in the docked position. For instance, if the evacuation station  100  were to operate in the evacuation mode when the filter bag  1050  is not present, debris contained in the air-debris flow  402  may become dislodged within the canister  110 , exhaust conduit  304 , and/or air mover  126 , restricting the flow of air to the exhaust  300  as well as causing damage to the motor and fan or impeller assembly  326  ( FIG. 5 ). 
     Referring to  FIG. 10A , in some implementations, the canister  110  includes a trapezoidal cross section allowing the canister  110  to rest flush against a wall in the environment to aesthetically enhance the appearance of the evacuation station  100 . The canister  110  may however, include a rectangular, polygonal, circular, or other cross section without limitation in other examples. The filter bag  1050  expands as the collected debris accumulates therein. Expansion of the filter bag  1050  into contact with interior walls  1010  of the canister  110  may result in debris only accumulating at a bottom portion of the filter bag  1050 , thereby chocking the air flow through the filter bag  1050 . In some implementations, the filter bag  1050  and/or interior walls  1010  of the canister  110  include protrusions  1080 , such as ribs, edges or ridges, disposed upon and extending away from the exterior surface of the filter bag  1050  and/or extending into the canister  110  from the interior walls  1010 . As the filter bag  1050  expands, the protrusions  1080  on the bag  1050  abut against the interior walls  1010  of the canister  110  to prevent the filter bag  1050  from fully expanding into the interior walls  1010 . Similarly, when the protrusions  1080  are disposed on the interior walls  1010 , the protrusions  1080  restrict the bag  1050  from fully expanding into flush contact with the interior walls  1010 . Accordingly, the protrusions  1080  ensure that an air gap is maintained between the filter bag  1050  and the interior walls  1010 , such that the filter bag  1050  cannot fully expand into contact the interior walls  1010 . In some examples, the protrusions  1080  are elongated ribs uniformly spaced in parallel around the exterior surface of the filter bag  1050  and/or the surface of the interior walls  1010 . The spacing between adjacent protrusions  1080  is small enough to prevent the filter bag  1050  from bowing out and into contact with the interior walls. In some implementations, the canister  110  is cylindrical and the protrusions  1080  are elongated ribs that run vertically down the length of the canister  110  and around the entire circumference of the canister  110  such that airflow continues to be uniform through the entire surface of the unfilled portion of bag even as debris compacts in the bottom of the bag. 
       FIG. 11  shows a schematic view of an example evacuation station  100  including an air particle separator device  750  and an air filtration device  1150 . The evacuation station  100  includes a base  120 , a collection bin  1120  and a ramp  130  for docking with the autonomic robotic cleaner  10 . The example robotic cleaner  10  docking with the ramp  130  is described above with reference to  FIGS. 1-5 ; however, other types of robots  10  are possible as well. In the example shown, the base  120  houses a first air mover  126   a  (e.g. a motor driven vacuum impeller) and the air particle separator device  750 . When the robot  10  is in the docked position, the first air mover  126   a  draws an air-debris flow  402  through a pneumatic debris intake conduit  202  to pull debris from within the debris bin  50  of the robotic  10 . The pneumatic debris intake conduit  202  provides the air-debris flow  402  from the debris bin  50  to a single stage particle separator  1152  of the air particle separator device  750 . The centrifugal force created by the geometry of the single stage particle separator  1152  causes the air-debris flow  402  to direct toward one or more collision walls  756  of the separator  1152 , causing particles to fall from the drawn air  402  and collect in the collection bin  1120  disposed beneath the single stage particle separator  1152 . A filter  1154  may be disposed above the single stage particle separator  1152  to prevent debris from being drawn up and through the first air mover  126   a  and damaging the first air mover  126   a.    
     A second air mover  126   b  of the air filtration device  1150  provides suction and draws the debris-free air flow  602  from the air mover  126   a  through and into the air filtration device  1150 . In some examples, the second air mover  126   b  of the air filtration device  1150  includes a fan/fin/impeller that spins. A particle filter  302  may remove small particles (e.g., ˜0.1 to ˜0.5 microns) from the debris-free air flow  602 . In some examples, the particle filter  302  is a HEPA filter  302  as described above with reference to  FIGS. 4 and 5 . Upon passing through the air particle filter  302 , the debris-free air flow  602  may exhaust into the environment external to the evacuation station  100 . 
     The air filtration device  1150  may further operate as an air filter for filtering environmental air external to the evacuation station  100 . For example, the second air mover  126   b  may draw the environmental air  1102  to pass through the HEPA filter  302 . In some examples, the air filtration device  1150  filters the environmental air via the HEPA filter  302  when the robot  10  is not received in the docked position, and/or the debris bin  50  of the robot  10  is not being evacuated. In other examples, the air filtration device  1150  simultaneously draws environmental air  1102  and debris-free flow  602  exiting the air particle separator device  750  through the HEPA filter  302 . 
     In some implementations, the collection bin  1120  is removably attached to the base  120 . In the example shown, the collection bin  1120  includes a handle  1122  for carrying the collection bin  1120  when removed from the base  120 . For instance, the collection bin  1120  may be detached from the base  120  when the handle  1122  is pulled by the user. The user may transport the collection bin  1120  via the handle  1122  to empty the collected debris when the collection bin  1120  is full. The collection bin  1120  may include a button-press actuated debris ejection door, similar to the debris ejection door  662  described above with reference to  FIG. 6 . This one button press debris ejection technique allows a user to empty the collection bin  1120  into a trash receptacle without having to touch the debris or any dirty surface of the collection bin  1120  to open or close the debris ejection door  662 . 
     In some implementations, referring to  FIGS. 12A and 12B , an example evacuation station  100  includes a flow control device  1250  in communication with a controller  1300  that selectively actuates the flow control device  1250  between a first position ( FIG. 12A ) when the evacuation station  100  operates in an evacuation mode and a second position ( FIG. 12B ) when the evacuation station  100  operates in an air filtration mode. In some examples, the flow control device  1250  is a flow control valve spring biased toward the first position or the second position. The flow control device  1250  may be actuated between the first and second positions to selectively block one air flow passage or another. 
     Referring to  FIG. 12A , when the robotic cleaner  10  is received in the docked position at the ramp  130 , the evacuation station  100  may operate in the evacuation mode to evacuate debris from the debris bin  50  of the robotic cleaner  10 . During the evacuation mode, in some examples, the controller  1300  activates an air mover  126  (motor and impeller) and actuates the flow control device  1250  to the first position, pneumatically connecting the pneumatic debris intake conduit  202  to the inlet  298  of the air mover  126 . An air-debris flow  402  may be drawn by the air mover  126  through the pneumatic debris intake conduit  202 . The canister  110  may enclose a filter  1260  in pneumatic communication with the pneumatic debris intake conduit  202  for filtering/separating debris out of the air-debris flow  402 . Additionally or alternatively, the canister  110  may enclose an air particle separator device  750  for separating the debris out of the air-debris flow  402 , as discussed in the examples above. A debris collection bin  660  may store accumulated debris that fall by gravity after being separated from the air-debris flow  304  by the filter  1260 . The flow control device  1250  in the first position pneumatically connects the exhaust conduit  304  to the inlet of  298  of the air mover  126 . Accordingly, upon separating/filtering debris out of the air-debris flow  402 , a debris-free air flow  602  may travel through the exhaust conduit  304  and into the air mover  126  and out the exhaust  300  when the flow control device  1250  is in the first position associated with the evacuation mode. The flow control device  1250 , while in the first position, also blocks environmental air  1202  ( FIG. 12B ) from being drawn by the air mover  126  through an environmental air inlet  1230  of the air mover  126  and out the exhaust  300 . 
     Referring to  FIG. 12B , when the robotic cleaner  10  is not in the docked position or the robotic cleaner  10  is in the docked position but the evacuation station is not evacuating debris, the evacuation station  100  may operate in the air filtration mode. During the air filtration mode, in some examples, the controller  1300  activates the air mover  126  and actuates the flow control device  1250  to the second position, pneumatically connecting the environmental air inlet  1230  to the exhaust  300  of the air mover  126  while pneumatically disconnecting the inlet  298  of the air mover  126  from the exhaust conduit  304 . For example, the air mover  126  may draw the environmental air  1202  via the environmental air inlet  1230  to pass through an air particle filter  302  such as a HEPA filter described above. Upon passing through the air particle filter  302  (e.g., HEPA filter) the environmental air  1202  may travel out the exhaust  300  and back into the environment. Since the flow control device  1250  in the second position pneumatically disconnects the inlet  298  from the exhaust conduit  304 , no air flow is drawn by the air mover  126  through the pneumatic debris intake conduit  202  or the exhaust conduit  304 . 
     Referring back to  FIGS. 2A-2B , air flow generated within the debris bin  50  of the robot  10  during the evacuation mode allows debris in the bin  50  to be sucked out and transported to the evacuation station  100 . The air flow within the debris bin  50  must be sufficient to permit the debris to be removed while avoiding damage to the bin  50  and a robot motor (not shown) housed within the bin  50 . When the robotic cleaner  10  is cleaning, the robot motor may generate an air flow to draw debris from the collection opening  40  into the bin  50  to collect the debris within the bin  50 , while permitting the air flow to exit the bin  50  through an exhaust vent (not shown) proximate the robot motor. The evacuation station can be used, for example, with a bin such as that disclosed in U.S. patent application Ser. No. 14/566,243, filed Dec. 10, 2014 and entitled, “DEBRIS EVACUATION FOR CLEANING ROBOTS”, which is hereby incorporated by reference in its entirety. 
       FIG. 13  shows an example controller  1300  enclosed within the evacuation station  100 . The external power supply  192  (e.g., wall outlet) may power the controller  1300  via the power cord  190 . The DC converter  1390  may convert AC current from the power supply  192  into DC current for powering the controller  1300 . 
     The controller  1300  includes a motor module  1702  in communication with the air mover  126  using AC current from the external power supply  192 . The motor module  1302  may further monitor operational parameters of the air mover  126  such as, but not limited to, rotational speed, output power, and electrical current. The motor module  1302  may activate the air mover  126 . In some examples, the motor module  1302  actuates the flow control valve  1250  between the first and second positions. 
     In some implementations, the controller  1300  includes a canister module  1304  receiving a signal indicating a canister full condition when the canister  110  has reached its capacity for collecting debris. The canister module  1304  may receive signals from the one or more capacity sensors  170  located within the canister (e.g., collection chambers or exhaust conduit  304 ) and determine when the canister full condition is received. In some examples, an interface module  1306  communicates the canister full condition to the user interface  150  by displaying a message indicating the canister full condition. The canister module  1304  may receive a signal from the connection sensor  420  indicating if the canister  110  is attached to the base  120  or if the canister  110  is removed from the base  120 . 
     In some examples, a charging module  1308  receives an indication of electrical connection between the one or more charging contacts  252  and the one or more a corresponding electrical contacts  25 . The indication of electrical connection may indicate the robotic cleaner  10  is received in the docked position. The controller  1300  may execute the first operation mode (e.g., evacuation mode) when the electrical connection indication is received at the charging module  1308 . The charging module  1308 , in some examples, receives an indication of electrical disconnection between the one or more charging contacts  252  and the one or more a corresponding electrical contacts  25 . The indication of electrical disconnection may indicate the robotic cleaner  10  is not received in the docked position. The controller  1300  may execute the second operation mode (e.g., air filtration mode) when the electrical disconnection indication is received at the charging module  1308 . 
     The controller  1300  may detect when the charging contacts  252  located upon the ramp  130  are in contact with the electrical contacts  25  of the robotic cleaner  10 . For example, the charging module  1308  may determine the robotic cleaner  10  has docked with the evacuation station  100  when the electrical contacts  25  are in contact with the charging contacts  252 . The charging module  1308  may communicate the docking determination to the motor module  1302  so that the air mover  126  may be powered to commence evacuating the debris bin  50  of the robotic cleaner  10 . The charging module  1308  may further monitor the charge of the battery  24  of the robotic cleaner  10  based on signals communicated between the charging and electrical contacts  25 ,  252 , respectively. When the battery  24  needs charging, the charging module  1308  may provide a charging current for powering the battery. When the battery  24  capacity is full, or no longer needs charging, the charging module  1308  may block the supply of charging through the electrical contacts  25  of the battery  24 . In some examples, the charging module  1308  provides a state of charge or estimated charge time for the battery  24  to the interface module  1306  for display upon the user interface  150 . 
     In some implementations, the controller  1300  includes a guiding module  1310  that receives signals from the guiding device  122  (emitter  122   a  and/or detector  122   b ) located on the base  120 . Based upon the signals received from the guiding device  122 , the guiding module may determine when the robot  10  is received in the docked position, determine a location of the robot  10 , and/or assist in guiding the robot  10  to toward the docked position. The guiding module  1310  may additionally or alternatively receive signals from sensors  232   a ,  232   b  (e.g., weight sensors) for detecting when the robot  10  is in the docked position. The guiding module  1310  may communicate to the motor module  1302  when the robot  10  is received in the docked position so that the air mover  126  can activated for drawing out debris from the debris bin  50  of the robot. 
     A bin module  1312  of the controller  1300  may indicate a capacity of the debris bin  50  of the robotic cleaner  10 . The bin module  1312  may receive signals from the microprocessor  14  and/or  54  of the robot  10  and the capacity sensor  170  that indicate the capacity of the bin  50 , e.g., the bin full condition. In some examples, the robot  10  may dock when the battery  24  is in need of charging but the bin  50  is not full of debris. For instance, the bin module  1312  may communicate to the motor module  1302  that evacuation is no longer needed. In other examples, when the bin  50  becomes evacuated of debris during evacuation, the bin module  1312  may receive a signal indicating that the bin  50  no longer requires evacuation and the motor module  1302  may be notified to deactivate the air mover  126 . The bin module  1312  may receive a collection bin identification signal from the microprocessor  14  and/or  54  of the robot  10  that indicates a model type of the debris bin  50  used by the robotic cleaner  10 . 
     In some examples, the interface module  1306  receives operational commands input by a user to the user interface  150 , e.g., an evacuation schedule and/or charging schedule for evacuating and/or charging the robot  10 . For instance, it may be desirable to charge and/or evacuate the robot  10  at specific times even though the bin  50  is not full and/or the battery  24  is not entirely depleted. The interface module  1306  may notify the guiding module  1310  to transmit honing signals through the guiding device  122  to call the robot  10  to dock during the time of a set charging and/or evacuation event specified by the user. 
       FIG. 14  provides an example arrangement of operations for a method  1400 , executable by the controller  1300  of  FIG. 13 , for operating the evacuation station  100  between an evacuation mode (e.g., a first operation mode) and an air filtration mode (e.g., a second operation mode). The flowchart starts at operation  1402  where the controller  1300  receives a first indication of whether the robotic cleaner  10  is received on the receiving surface  132  in the docked position, and at operation  1404 , receives a second indication of whether the canister  110  is connected to the base  120 . The controller  1300  may receive the first and second indications of operations  1802 ,  1804 , respectively, in any order or in parallel. In some examples, the first indication includes the controller  1300  receiving an electrical signal from the one or more charging contacts  252  disposed on the receiving surface  132  that interface with electrical contacts  25  when the robotic cleaner  10  is in the docked position. In some examples, the second indication includes the controller  1300  receiving a signal from the connection sensor  420  sensing connection of the canister  110  to the base  120 . 
     At operation  1406 , when the first indication indicates the robotic cleaner  10  is received on the receiving surface  132  of the ramp  130  in the docked position and the second indication indicates that the canister  110  is attached to the base  120 , the controller  1300  executes the evacuation mode (first operation mode) at operation  1408  by actuating the flow control device  1250  to move to the first position ( FIG. 12A ) that pneumatically connects the evacuation intake opening  200  to the canister  110  and activates the air mover  126  to draw air into the evacuation intake opening  200  to draw debris from the debris bin  50  of the docked robotic cleaner  10  into the canister  110 . However, when at least one of the first indication indicates the robotic cleaner  10  is not received on the receiving surface  132  in the docked position or the second indication indicates that the canister  110  is disconnected from the base  120  at operation  1406 , the controller  1300 , at operation  1410 , executes the air filtration mode (second operation mode) by actuating the flow control valve  1250  to move to the second position ( FIG. 12B ) that pneumatically connects the environmental air inlet  1230  ( FIGS. 12A and 12B ) to the exhaust  300  of the air mover  126  while pneumatically disconnecting the inlet  298  of the air mover  126  from the exhaust conduit  304 . During the air filtration mode, the air mover  126  may draw environmental air  1202  through the environmental air inlet  1230  and the particle filter  302  and out the exhaust  300 . In some implementations, operation  1408  additionally detects whether or not the evacuation mode is executing or has recently stopped executing. When operation  1406  determines the evacuation mode is not executing, the controller  1300 , at operation  1410 , executes the air filtration mode even though the canister  110  is attached to the base  120  and the robotic cleaner  10  is received in the docked position. 
     While operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multi-tasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.