Patent Publication Number: US-11641988-B2

Title: Evacuation station system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and claims priority to U.S. application Ser. No. 15/858,912, filed Dec. 29, 2017, entitled “EVACUATION STATION,” which is a continuation of and claims priority to U.S. application Ser. No. 14/634,170, filed Feb. 27, 2015, titled “EVACUATION STATION SYSTEM,” which is a continuation of and claims priority to U.S. application Ser. No. 13/345,270, filed Jan. 6, 2012, entitled “EVACUATION STATION SYSTEM,” which claims priority to U.S. Provisional Application Ser. No. 61/430,896, filed Jan. 7, 2011, titled “EVACUATION STATION SYSTEM,” the entire contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to cleaning systems for coverage robots. 
     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 coverage robot 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 
     In general, one aspect of the subject matter described in this specification can be embodied in a cleaning system comprising: a portable vacuum including a vacuum motor, a cleaning head, an evacuation port, and a bypass mechanism configured to direct suction from the vacuum motor to either the cleaning head or the evacuation port; a robotic cleaner including a debris bin and an evacuation port assembly for the debris bin; and an evacuation station including a vacuum interface configured to mate with the portable vacuum, a cleaner interface configured to mate with the robotic cleaner, and a linkage connecting the evacuation port assembly of the debris bin and the evacuation port of the portable vacuum, wherein the evacuation station is configured to engage the bypass mechanism on mating with the portable vacuum to direct suction from the vacuum motor to the evacuation port. 
     These and other embodiments can each optionally include one or more of the following features. The cleaner interface includes an evacuation connector formed of compliant material coupled to the linkage. The evacuation connector is generally rectangular and defines a hole through which air and debris can flow into the linkage. The evacuation connector is configured to move with one degree of freedom. The evacuation connector is curved and configured to mate with a spherical shell of the robotic cleaner. The evacuation connector includes a poker configured to engage a port door of the evacuation port assembly. The poker includes a reed switch coupled to a controller of the portable vacuum, and wherein the port door includes a magnet. The port door is configured to form a seal that is substantially air tight when not in contact with the poker. The debris bin includes a microprocessor and a serial connection to the robotic cleaner. The debris bin includes a navigational sensor coupled to the microprocessor. The microprocessor is configured to communicate a bin full signal to the robotic cleaner using the serial connection. The microprocessor is configured to communicate a navigational signal to the robotic cleaner using the serial connection. The robotic cleaner includes an omnidirectional navigational sensor on a forward end opposite the debris bin and bin sensor on the debris bin. The bin sensor is configured to receive omnidirectionally, within 180 degrees, or within 90 degrees. 
     In general, another aspect of the subject matter described in this specification can be embodied in a method performed by a robotic cleaner for evacuation a debris bin of the robotic cleaner, the method comprising: determining a bin full event has occurred; navigating to an evacuation station; docking front-first at the evacuation station, wherein a front of the robotic cleaner is substantially opposite the debris bin; backing out of the evacuation station and rotating approximately 180 degrees; docking bin-first at the evacuation station; and waiting while the evacuation station vacuums debris from the debris bin for an amount of time. 
     These and other embodiments can each optionally include one or more of the following features. The method further comprises driving away from the evacuation station. The method further comprises determining that a battery is low on charge, driving away from the evacuation station, rotating 180 degrees, and docking front-first at the evacuation station to contact at least one electrical charging contact. Determining a bin full event has occurred includes receiving a bin full signal from the debris bin. The bin full signal is based on input from debris sensors in the debris bin. Docking bin-first at the evacuation station comprises using a navigational sensor on the debris bin. 
     In general, another aspect of the subject matter described in this specification can be embodied in a cleaning system comprising: an evacuation station including a portable vacuum; a robotic cleaner; a bin in the robotic cleaner configured to collect debris, the bin including a port door; and an evacuation connector coupled to an evacuation chamber of the evacuation station, the evacuation connector configured to open the port door on the bin of the robotic cleaner when the robotic cleaner drives into the evacuation station; wherein the bin includes a downwardly extending baffle behind the port door, the baffle being configured to direct evacuating suction from the portable vacuum of the evacuation station downwardly to reach a bottom of the bin. 
     These and other embodiments can each optionally include one or more of the following features. The bin includes vertical side wall next to the baffle and the port door, and the baffle is configured to direct evacuating suction along the vertical side wall. The bin includes a filter next to the baffle, the filter being configured to block debris from flowing into a vacuum fan and to allow debris to accumulate at the bottom of the bin. The bin includes a bevel on the bottom of the bin, and the baffle is configured to direct the evacuating suction across the bevel to the bottom of the bin. The evacuation connector is configured to rotate about a pivot as the robotic cleaner docks with the evacuation station. 
     In general, another aspect of the subject matter described in this specification can be embodied in a robotic cleaner comprising: a drive system configured to move the robotic cleaner about a coverage area; a vacuum motor to collect debris from the coverage area; and a bin to store collected debris from the coverage area, the bin comprising: an exhaust vent for the vacuum motor; a filter between the vacuum motor and a bottom of the bin; a port door next to the exhaust vent for evacuating the bin; a vertical side wall; and a downwardly extending baffle behind the port door, the baffle being configured to direct evacuating suction downwardly along the vertical side wall to reach the bottom of the bin. 
     These and other embodiments can each optionally include one or more of the following features. The bin includes a bevel on the bottom of the bin, and the baffle is configured to direct the evacuating suction across the bevel to the bottom of the bin. The baffle is curved along a direction from the filter to the vertical side wall. The port door is configured to rotate so that when the port door is open part of the port door recedes into a pocket volume. The bin further comprises a spring configured to hold the port door closed until engaged by a poker of an evacuating connector. 
     Particular embodiments of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages. A robotic cleaner can empty a bin holding debris without human interaction. The robotic cleaner can cover larger coverage areas without requiring a larger bin by emptying its bin. The bin can be emptied into a portable vacuum, for example, that can provide evacuating suction and be conveniently emptied. The bin includes features, for example a baffle and a bevel, that route evacuating suction to the bottom of the bin where debris accumulates. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIGS.  1 - 2    illustrate a cleaning system including a robotic cleaner, an evacuation station, and a portable vacuum. 
         FIGS.  3 A- 3 B  illustrate an example robotic cleaner. 
         FIG.  3 C  is a schematic diagram of an example robotic cleaner including a bin navigation sensor on a bin. 
         FIG.  4 A  is a perspective view of an example robotic cleaner showing an evacuation port assembly of the cleaning bin. 
         FIG.  4 B  is a perspective view of an example robotic cleaner showing an alternative evacuation port assembly of the cleaning bin. 
         FIG.  5    is a schematic diagram of an example removable cleaning bin. 
         FIGS.  6 A- 6 B  illustrate a bin-full detection system for sensing an amount of debris present in the bin. 
         FIGS.  7 A- 7 D  are front, side, top, and perspective views of an evacuation connector. 
         FIGS.  8 A- 8 B  are schematic diagrams illustrating a robotic cleaner docking to connect to an evacuation connector. 
         FIG.  9    illustrates an example evacuation station. 
         FIG.  10    is a flow diagram of an example process for evacuating a bin of a robotic cleaner. 
         FIG.  11    is a schematic diagram of an evacuation station and an example portable vacuum. 
         FIGS.  12 A- 12 B  are schematic diagrams of an example bypass mechanism for a portable vacuum. 
         FIGS.  13 A-D  show a sequence of events that occur during an example docking operation between an example robotic cleaner and an example evacuation station. 
         FIGS.  14 A-C  show overhead views of a sequence of events that occur during an example docking operation between an example robotic cleaner and an example evacuation station. 
         FIG.  15 A  shows a side view of airflow through an example robotic cleaner during normal vacuum operation, e.g., when the robotic cleaner is vacuuming debris off of a floor. 
         FIG.  15 B  is a schematic side view of airflow through the example robotic cleaner during evacuation to an evacuation station. 
         FIG.  16 A  is a schematic view of the inside of a bin of a robotic cleaner. The view is from the inside of the bin facing out. 
         FIG.  16 B  is a schematic view of a bin that does not show a motor or a filter. 
         FIG.  16 C  is a schematic view of the bin with the port door on top of the bin. 
         FIG.  17    is a schematic view of a bin having a port door on the top of the bin. 
         FIG.  18    is a view of a bin for a robotic cleaner from the outside. 
         FIG.  19    is a view of a bin for a robotic cleaner from the inside looking out. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIGS.  1 - 2    illustrate a cleaning system including a robotic cleaner  10 , an evacuation station  100 , and a portable vacuum  400 .  FIG.  1    is a schematic side view of the system.  FIG.  2    is a schematic overhead view of the system. 
     The robotic cleaner  10  includes a bin  50 . While cleaning, the robotic cleaner  10  collects debris in the bin  50 . When the robotic cleaner  10  detects that the bin  50  is full, the robotic cleaner  10  navigates to the evacuation station  100 . The robotic cleaner docks with a cleaner interface  200  to the evacuation station  100 . The portable vacuum  400  connects to the evacuation station using a vacuum interface  300 . The portable vacuum  400  provides suction and/or airflow to remove debris from the robotic cleaner&#39;s bin  50 . The portable vacuum  400  stores the removed debris. Evacuating the robotic cleaner&#39;s bin into the portable vacuum  400  is useful, for example, because the robotic cleaner can operate without human intervention for longer periods of time. 
     The evacuation station  100  may be connected to an AC power source, e.g., by a power cord  102 . The evacuation station  100  may charge a battery on the robotic cleaner  10  through the cleaner interface  200 . The evacuation station  100  may also provide and receive control signals with the robotic cleaner  10  through the cleaner interface (e.g., a signal to begin evacuation). 
     The evacuation station  100  may charge a battery on the portable vacuum  400  through the vacuum interface  300 . The evacuation station  100  may provide AC power to the portable vacuum  400  through the vacuum interface  300 . The evacuation station  100  may provide and receive control signals (e.g., a signal to begin evacuation) with the portable vacuum  400  through the vacuum interface  300 . 
     The portable vacuum  400  may be a handheld vacuum cleaner. The portable vacuum  400  may be a hip pack or backpack vacuum. For example, the portable vacuum  400  may be designed to be carried by rigorous supports, e.g., supports used for hiking and the like. 
       FIGS.  3 A- 3 B  illustrate an example robotic cleaner  10 . The robotic cleaner  10  includes a chassis  31  which carries an outer shell  6 .  FIG.  3 A  illustrates the outer shell  6  of the robot  10  connected to a bumper  5 . The robot  10  may move in forward and reverse drive directions; consequently, the chassis  31  has corresponding forward and back ends,  31 A and  31 B respectively. The forward end  31 A is fore in the direction of primary mobility and in the direction of the bumper  5 ; the robot  10  typically moves in the reverse direction primarily during escape, bounces, and obstacle avoidance. A cleaning head assembly  40  is located towards the middle of the robot  10  and installed within the chassis  31 . The cleaning head assembly  40  includes a main brush  60  and a secondary parallel brush  65  (either of these brushes may be a pliable multi-vane beater or a have pliable beater flaps  61  between rows of brush bristles  62 ). A battery  25  is housed within the chassis  31  proximate the cleaning head  40 . In some examples, the main  65  and/or the secondary parallel brush  60  are removable. In other examples, the cleaning head assembly  40  includes a fixed main brush  65  and/or secondary parallel brush  60 , where fixed refers to a brush permanently installed on the chassis  31 . 
     Installed along either side of the chassis  31  are differentially driven wheels  45  that mobilize the robot  10  and provide two points of support. The forward end  31 A of the chassis  31  includes a caster wheel  35  which provides additional support for the robot  10  as a third point of contact with the floor and does not hinder robot mobility. Installed along the side of the chassis  31  is a side brush  20  configured to rotate 360 degrees when the robot  10  is operational. The rotation of the side brush  20  allows the robot  10  to better clean areas adjacent the robot&#39;s side by brushing and flicking debris beyond the robot housing in front of the cleaning path, and areas otherwise unreachable by the centrally located cleaning head assembly  40 . A removable cleaning bin  50  is located towards the back end  31 B of the robot  10  and installed within the outer shell  6 . 
       FIG.  3 C  is a schematic diagram of an example robotic cleaner  10  including a bin navigation sensor  59  on a bin  50 . In some implementations, the robot  10  includes a receiver  1020  (e.g., an infrared receiver) and the bin  50  includes a corresponding emitter  1022  (e.g., an infrared emitter). The emitter  1022  and receiver  1020  are positioned on the bin  50  and robot  10 , respectively, such that a signal transmitted from the emitter  1022  reaches the receiver  1020  when the bin  50  is attached to the robot  10 . For example, in implementations in which the receiver  1020  and the remitter  1022  are infrared, the emitter  1022  and the receiver  1020  are positioned relative to one another to facilitate line-of-sight communication between the emitter  1022  and the receiver  1020 . In some examples, the emitter  1022  and the receiver  1020  both function as emitters and receivers, allowing bi-directional communication between the robot  11  to the bin  50 . 
     In some examples, the robot  10  includes an omni-directional receiver  13  on the chassis  31  and configured to interact with a remote virtual wall beacon  1050  that emits and receives infrared signals. A signal from the emitter  1022  on the bin  50  can be receivable by the omni-directional receiver  13  and/or the remote virtual wall beacon  1050  to communicate, e.g., a bin fullness signal, or navigational signals from a bin navigation sensor  59 . While infrared communication between the robot  10  and the bin  50  has been described, one or more other types of wireless communication may additionally or alternatively be used to achieve such wireless communication. Examples of other types of wireless communication between the robot  10  and the bin  50  include electromagnetic communication and radiofrequency communication. 
     The bin fullness signal can trigger the robot  10  to navigate to an evacuation station to empty debris from the bin  10 . The robot  10  may use the bin navigation sensor  59  to dock with an evacuation station, e.g., when the robot  10  is docking bin-first so that the bin faces the evacuation station. The bin navigation sensor  59  may be an omnidirectional sensor, e.g., an omnidirectional infrared receiver. Alternatively, the bin navigation sensor  59  may be a 90 degree sensor or a 180 degree sensor. 
       FIG.  4 A  is a perspective view of an example robotic cleaner  10  showing an evacuation port assembly  80  of the cleaning bin  50 . The evacuation port assembly  80  may include a port cover  55 . In some implementations, the port cover  55  includes a panel or panels  55 A,  55 B which may slide (or be otherwise translated) along a side wall of the chassis  31  and under or over side panels of the outer shell  6  to open the evacuation port assembly  80 . The evacuation port assembly  80  is configured to mate with the cleaner interface  200  of the evacuation station  100 . In some implementations, the evacuation port assembly  80  is installed along an edge of the outer shell  6 , on a top most portion of the outer shell  6 , on the bottom of the chassis  31 , or other similar placements where the evacuation port assembly  80  has ready access to the contents of the cleaning bin  50 . In some implementations, the evacuation port assembly  80  includes a single evacuation port  80 A. In some implementations, the evacuation port assembly  80  includes a plurality of evacuation ports  80 A,  80 B,  80 C that are distributed across the cleaning bin  50 . 
       FIG.  4 B  is a perspective view of an example robotic cleaner showing an alternative evacuation port assembly  80  of the cleaning bin  50 . In  FIG.  4 B , the evacuation port assembly  80  is offset from the center of the rear of the bin  50 . An outlet  90 , e.g., of a vacuum, occupies the center of the rear of the bin  50 . The evacuation port assembly  80  may include a spring loaded door, e.g., a port door on a hinge. In some implementations, the port door opens at the bottom when a poker engages the top of the port door. 
       FIG.  5    is a schematic diagram of an example removable cleaning bin  50 . The cleaning bin  50  may be removable from the chassis  31  to provide access to bin contents and an internal filter  54 . 
       FIGS.  6 A- 6 B  illustrate a bin-full detection system for sensing an amount of debris present in the bin  50 . The bin-full detection system includes an emitter  755  and a detector  760  housed in the bin  50 . A housing  757  surrounds each of the emitter  755  and the detector  760  and is substantially free from debris when the bin  50  is also free of debris. In some implementations, the bin  50  is detachably connected to the robotic cleaner  11  and includes a brush assembly  770  for removing debris and soot from the surface of the emitter/detector housing  757 . The brush assembly  770  includes a brush  772  mounted on the robot body  31  and configured to sweep against the emitter/detector housing  757  when the bin  50  is removed from or attached to the robot  11 . The brush  772  includes a cleaning head  774  (e.g. bristles or sponge) at a distal end farthest from the robot  11  and a window section  776  positioned toward a base of the brush  772  and aligned with the emitter  755  or detector  760  when the bin  50  is attached to the robot  11 . The emitter  755  transmits and the detector  760  receives light through the window  776 . In addition to brushing debris away from the emitter  755  and detector  760 , the cleaning head  774  reduces the amount of debris or dust reaching the emitter  755  and detector  760  when the bin  50  is attached to the robot  11 . In some examples, the window  776  comprises a transparent or translucent material and is formed integrally with the cleaning head  774 . In some examples, the emitter  755  and the detector  760  are mounted on the chassis  31  of the robot  11  and the cleaning head  774  and/or window  776  are mounted on the bin  50 . 
     In some implementations, the bin  50  includes a microprocessor  57 . For example, the microprocessor may be connected to the emitter and detector  755  and  760  to execute an algorithm to determine whether the bin is full. The microprocessor may also be connected to a bin navigation sensor  59 . The microprocessor  57  may communicate with the robotic cleaner  10  from a bin serial port  58  to a robot serial port  12 . The serial ports  58  and  12  may be, for example, mechanical terminals or optical devices. For example, the microprocessor  57  may report bin full events to the robotic cleaner  10 , or report a signal that the robotic cleaner has docked (e.g., based on signals from the bin navigation sensor  59 ), or report other events from the bin navigation sensor  59 . 
       FIGS.  7 A- 7 D  are front, side, top, and perspective views of an evacuation connector  202 . The cleaner interface  200  includes the evacuation connector  202 . The evacuation connector  202  is formed of compliant material, e.g., any of various types of foams, elastomers, or rubbers. In implementations where the evacuation connector  202  is formed of foam, the evacuation connector  202  can include harder and softer layers, e.g., with the softer layer on the outside for contacting a robotic cleaner  10 . The foam can have a durometer in the range of foam used for weatherstripping. 
     The evacuation connector  202  defines a hole  208  through which air and debris can flow between the robotic cleaner  10  and an evacuation station  100 . For example, the evacuation connector  202  may be rectangular, as is shown in  FIGS.  7 A- 7 D . The evacuation connector  202  may be formed of rectangular pieces of the compliant material stacked on top of each other. The evacuation connector  202  may be curved to improve mating with a circular robotic cleaner. The evacuation connector  202  includes a poker  206  that is configured to open an evacuation port assembly  80  for evacuation. 
       FIGS.  8 A- 8 B  are schematic diagrams illustrating a robotic cleaner  10  docking to connect to an evacuation connector  202 . The robot  10  is guided or aligned so that the evacuation port assembly  80  on the robot cleaning bin  50  engages the evacuation connector  202 . The robot  10  may be guided by a homing signal, tracks on a platform, guide rails, a lever, or other guiding devices. The evacuation connector  202  opens a port door  56  on the robot cleaning bin  50  when the robot  10  docks. 
     The port door  56  is configured to be substantially airtight when closed, e.g., as shown in  FIG.  8 A . The port door  56  and evacuation port assembly  80  are configured to be evacuable when opened, e.g., as shown in  FIG.  8 B . For example, the evacuation port assembly  80  may include a baffle to shape airflow within the bin  50  during evacuation. The baffle and evacuation port assembly  80  create an airflow channel from the top of the bin  50  to the bottom of the bin  50 , even though the bin evacuates from the evacuation port assembly  80  which is on the side of the bin. This is useful, for example, so that bin  50  more completely empties of debris during evacuation. In some implementations, the bin  50  is a joint sweeping-vacuuming bin. 
     In some implementations, the evacuation port assembly  80  and evacuation connector  202  are configured to signal an evacuation station  100  to begin evacuation when the evacuation port assembly  80  mates with the evacuation connector  202 . For example, the port door  56  may include one or more magnets, and the poker  206  of the evacuation connector  202  may include one or more reed switches. The reed switches may be connected to a controller on the evacuation station  100  or directly to a portable vacuum  400 . In general, the evacuation port assembly  80  includes a passive element that does not draw power and can signal the evacuation connector  202 . The evacuation connector  202  includes a receiver to match the passive element. The receiver may be, for example, a reed switch, a Hall effect receiver, a photointerruptor, or the like. 
       FIG.  9    illustrates an example evacuation station  100 . The evacuation station  100  includes a cleaner interface  200  and a vacuum interface  300 . The cleaner interface includes an evacuation connector  202 . The evacuation connector  202  empties into an air chamber  210  configured to connect to a vacuum. In some implementations, the evacuation connector  202  has one or more degrees of freedom of movement. For example, the evacuation connector  202  may be mounted on a swivel or hinge. The evacuation connector  202  is then free to move from side to side to form a better seal with a curved plane, e.g., on a robotic cleaner  10 . 
     The cleaner interface also includes a lower platform  204  and an upper platform  206  for receiving a robotic cleaner  10 . The upper platform  206  is raised compared to the lower platform, for example, to assist the robotic cleaner  10  in docking with the evacuation station  100 . The upper platform  206  includes two electrical contacts  208   a  and  208   b . The electrical contacts  208   a  and  208   b  are useful, for example, to charge the robotic cleaner  10 , to guide the robotic cleaner  10  (e.g., indicate when the robotic cleaner  10  is docked), or both. 
     In some implementations, the electrical contacts  208   a  and  208   b  are positioned to align with the electrical contacts on the robotic cleaner  10  when the robotic cleaner  10  docks front-first, so that the bin  50  of the robotic cleaner faces away from the evacuation station  100 . The robotic cleaner  10  then charges while docked front-first. The evacuation connector  202  is position to align with the evacuation port assembly  80  when the robot docks bin-first, so that the bin  50  of the robot cleaner faces the evacuation station  100 . When the robotic cleaner  10  docks bin-first, the evacuation station evacuates the bin  50 . 
       FIG.  10    is a flow diagram of an example process  1000  for evacuating a bin of a robotic cleaner. The process  1000  is performed by the robotic cleaner. The robotic cleaner may be, for example, the robotic cleaner  10  of  FIGS.  3 A and  3 B  including the bin  50  of  FIG.  5   . 
     The robotic cleaner determines that a bin full event has occurred (step  1002 ). For example, the robotic cleaner may receive a bin full signal from a bin as described above with reference to  FIGS.  6 A- 6 B . 
     The robotic cleaner navigates to an evacuation station (step  1004 ). The robotic cleaner may use various methods of navigation, and may need to traverse a household to reach the evacuation station. 
     The robotic cleaner docks to the evacuation station front-first (step  1006 ). For example, the robotic cleaner may use a front-facing omnidirectional sensor (e.g., the sensor  13  of  FIG.  3 C ) to properly align with the evacuation station. The robotic cleaner may also use electrical contacts (e.g., the electrical contacts  208   a  and  208   b  of  FIG.  9   ) to align itself with the evacuation station. The robotic cleaner docks front-first, for example, because it has a better sensor in the front or its contacts are designed to contact the evacuation station during front-first docking. Thus, the robotic cleaner can align itself with the dock first using front-first docking and then dock bin-first to evacuate the bin. In some implementations, the robotic cleaner may wait and charge its battery while docked front-first (e.g., where the batteries are low and the robotic cleaner cannot charge while docked bin-first). 
     The robotic cleaner backs away from the evacuation station and rotates 180 degrees (step  1008 ). The robotic cleaner may back a specified distance to ensure that it has sufficient space to rotate. For example, the robotic cleaner may back up far enough so that it clears the lower platform  204  of the example evacuation station of  FIG.  9   . 
     The robotic cleaner docks bin-first (step  1010 ). For example, the robotic cleaner may use the bin navigational sensor  59  of  FIG.  3 C  to properly align with the evacuation station. The robotic cleaner may also use electrical contacts (e.g., the electrical contacts  208   a  and  208   b  of  FIG.  9   ) for alignment while backing into the evacuation station. 
     The robotic cleaner waits during bin evacuation (step  1012 ). For example, the evacuation station may detect that the robotic cleaner has docked properly (e.g., using magnets and reed switches as described above with respect to  FIGS.  8 A- 8 B ) and send a control signal to a portable vacuum to begin providing suction. The evacuation station or the portable vacuum includes a timing mechanism configured to provide suction for a specified amount of time. The amount of time may be based on a size of the robotic cleaner&#39;s bin. If the evacuation station evacuates different types of bins, the evacuation station may receive a signal indicating a size or an evacuation time. 
     The robotic cleaner drives forward away from the evacuation station (step  1014 ). Depending on the state of charge of the robotic cleaner&#39;s batteries, it may continue cleaning as it was before the bin full event, or it may drive forward, rotate 180 degrees and dock front-first to charge its batteries. 
       FIG.  11    is a schematic diagram of an evacuation station  100  and an example portable vacuum  400 . The portable vacuum  400  includes a vacuum motor  402  configured to suck air into the portable vacuum  400 . The portable vacuum  400  is configurable to suck air through either a cleaning head including a standard vacuum attachment  404  (e.g., a conical apparatus including brushes on rollers, or a tube connected to a slotted channel cleaning head, or the like) or through an evacuation port  406  configured to mate with the vacuum interface  300  of the evacuation station  100 . In some implementations, the portable vacuum  400  is generally configured to suck air through the standard vacuum attachment  400 . When the portable vacuum  400  mates with the vacuum interface  300  of the evacuation station  100 , the portable vacuum  400  becomes configured to suck air through the evacuation port  406 . For example, the portable vacuum  400  may include a mechanical bypass, e.g., a valve, that routes suction from the vacuum motor  402  to either the standard vacuum attachment  404  or the evacuation port  406 . The force of a person pushing the portable vacuum  400  into the evacuation station  100  may actuate the valve. 
     In another example, the portable vacuum  400  may include an electrically actuated valve. The electrically actuated valve may draw power through the evacuation station  100 . For example, the force of a person pushing the portable vacuum  400  into the evacuation station  100  may mate charging connectors for the portable vacuum  400  to the evacuation station  100 , which may be, e.g., plugged into a wall socket. The vacuum interface  300  may include features for increasing the reliability of the mating between the portable vacuum  400  and the evacuation station  100 . For example, the vacuum interface  300  may include a mechanical alignment structure (e.g., a tapered structure for guiding), electrical terminals including spring biasing or detents, or the like. 
     If the portable vacuum  400  is a corded vacuum, the evacuation station may have an AC plug, and the evacuation station  100  may be configured to pass AC current directly to the portable vacuum  400 . Alternatively, the portable vacuum  400  can be plugged directly into the wall and powered without drawing power from the evacuation station  100 . 
     In some implementations, the vacuum interface  300  includes a custom port. The portable vacuum  400  may be an AC or DC vacuum with, e.g., a custom power thin cord (e.g., retractable, spoolable, or both) to match the custom port. The evacuation station  100  may include power adapters (e.g., wall warts) for AC plugs for custom power. 
     The evacuation port  406 , separate from the standard vacuum attachment  404 , is useful for a number of reasons. Mating a standard vacuum attachment  404  may adversely affect its efficacy in normal use (e.g., by wearing parts down by friction), or be difficult to configure for reliable airtight mating. Moreover, a brush or slotted channel cleaning head may reduce the air velocity and thus the ability of the portable vacuum  400  to thoroughly evacuate debris from a robotic cleaner&#39;s bin  50 . 
     In some implementations, the evacuation port  406  is configured for high air velocity. For example, the evacuation port  406  may include a tube having a small diameter, e.g., 1.5 inches or less. The tube is preferentially round, unobstructed, substantially straight, lacks sharp turns, and minimizes any turns. The tube may be wide enough to pass certain kinds of debris; for example, the tube may have a diameter of at least % of an inch to pass two cheerios. An airflow of 0.0188 m{circumflex over ( )}3/s is sufficient for evacuation in some implementations. 
       FIGS.  12 A- 12 B  are schematic diagrams of an example bypass mechanism  408  for a portable vacuum  400 . When the portable vacuum  400  is not mated to a vacuum interface  300  of an evacuation station, the portable vacuum  400  draws air through a standard vacuum attachment  404 . When the portable vacuum  400  is mated to the vacuum interface  300 , a poker  302  of the vacuum interface  300  engages the bypass mechanism  408  to configure the portable vacuum  400  to draw air through an evacuation port  406 . 
       FIGS.  13 A-D  show a sequence of events that occur during an example docking operation between an example robotic cleaner  10  and an example evacuation station. During docking, the robotic cleaner moves closer to the evacuation station, creating a seal between a port door  56  of a bin  50  and an evacuation connector  202 , so that debris  1302  can be evacuated from the bin  50  into the evacuation station. The debris  1302  can accumulate at the bottom of the bin  50  by gravity. 
     The evacuation connector  202  leads to an evacuation chamber  210  which is connected to, e.g., a hose  212 . A hose  212  upstream of the evacuation connector  202  can be useful, for example, to maintain circular cross section air flow while absorbing lateral movement. Hence the hose  212  can be useful even if evacuation station includes a mechanically docked hand vacuum (e.g.,  FIG.  11   ). The evacuation station also includes a poker  206  configured to engage the port door  56  during docking and open the port door  56 . 
     The robotic cleaner  10  includes a sweeping chamber  14  that includes, for example, a vacuum motor and rollers. The bin  50  includes a filter  54  and a bin door  64 . The filter  54  allows air to pass during cleaning and collects debris  1302 . The bin  50  is shaped by a bin upper wall  66 , a bevel  68 , and a vertical baffle  70 . The baffle  70  is configured to route horizontal airflow from the evacuation connector  202  to vertical airflow, providing a path for the debris  1302  out of the bin  50 . 
     The evacuation connector can include a reed switch  214 . The reed switch  214  is configured to be actuated when a magnet  72  in the bin  50  is brought within a certain distance of the reed switch  214 . When the robotic cleaner  10  is docked, the reed switch  214  activates a vacuum that provides suction to evacuate the bin  50 . Alternatively, a mechanical switch can be used to activate the vacuum that provides suction to evacuate the bin  50 . 
     In  FIG.  13 A , the poker begins to engage the port door  56  as the robotic cleaner approaches. In  FIG.  13 B , the poker has pushed the port door  56  has been opened by the poker  206 . Because the port door  56  opens by the motion of the robotic cleaner docking, additional actuators need not be present to rotate the port door  56 . The robotic cleaner is configured to dock with enough force to open the port door  56  even though the port door is normally secured closed (e.g., the robotic cleaner can overcome the force of a spring that secures the port door.) 
     In  FIG.  13 C , the evacuation connector contacts the bin, forming a seal. The vacuum of the evacuation station is activated (e.g., by the reed switch  214 , or a mechanical switch). In  FIG.  13 D , the debris  1302  is evacuated from the bin  50  into the evacuation station. 
       FIGS.  14 A-C  show overhead views of a sequence of events that occur during an example docking operation between an example robotic cleaner  10  and an example evacuation station. The robotic cleaner  10  includes a bin with a filter  54 , a baffle  70  configured to direct horizontal airflow to a vertical direction, a bin door  64 , and a port door  56 . The baffle  70  can be a curved wall. 
     The baffle  70  can be configured to extend the airflow directed by the baffle  70  a certain distance laterally, for example, more than 1/10 the width of the bin, or nearly ⅕ the width of the bin or more. The baffle  70  can be curved, for example, so that it does not consume more bin volume (e.g., than a lower diameter tube) and still directs airflow further into the bin than a flat wall would. 
     The evacuation station includes an evacuation connector  202 , an evacuation chamber  210  coupled to the evacuation connector  202  to receive debris, and a pivot  216  that the evacuation connector  202  rotates about. The evacuation chamber  210  can also rotate about the pivot  216 . 
     In  FIG.  14 A  the robotic cleaner  10  begins to approach the evacuation station. The robotic cleaner  10  aligns along a center line of a docking corridor of the evacuation station, and then moves towards the evacuation station. The docking corridor is configured to tolerate some error by the robotic cleaner  10  in its alignment with the center line, e.g., 10 degrees or less of error. 
     In  FIG.  14 B , the robotic cleaner  10  makes contact with the evacuation connector, a protruding stopping member  218 , or both. The protruding stopping member protrudes from the side of the evacuation station opposite the side with the evacuation connector  202 . 
     By contacting both the evacuation connector  202  and the protruding stopping member  218 , the robotic cleaner can create a firm seal (e.g., substantially airtight) between the evacuation connector  202  and the port door  56  as the evacuation connector  202  rotates about the pivot  216 . As described above, the evacuation connector  202  can be formed of foam or other material that permits resilient contact and also supports the firm seal. 
     A stopper  224  on the side of the evacuation connector  202  opposite the robotic cleaner  10  prevents the evacuation connector  202  from rotating too far about the pivot  216 . For example, the stopper  224  can be configured so that the evacuation connector  202  can pivot through 40 degrees. Although the evacuation connector  202  is shown as being offset from the center line (to match the port door  56  which is not in the center of the robot  10 ), the port door  56  and the evacuation connector  202  can be aligned with the center line of the docking corridor. In that case, the evacuation connector  202  can be constrained (e.g., by the stopper  224 ) to rotate only through 5-20 degrees. 
     The evacuation connector  202  can have a curvature that is wide enough to assist in forming a seal even though there is uncertainty in the position of the port door  56  (e.g., because of navigational uncertainty). For example, the evacuation connector  202  can be about two times or three times the width of the opening by the port door  56 . 
     In  FIG.  14 C , the robotic cleaner is pressed against both the protruding stopping member  218  and the evacuation connector  202 . A substantially airtight seal is formed between the evacuation connector  202  and the open port door  56 . The evacuation connector  202  is substantially aligned with the rear wall of the robotic cleaner  10  when docked. 
       FIG.  15 A  shows a side view of airflow through an example robotic cleaner  10  during normal vacuum operation, e.g., when the robotic cleaner  10  is vacuuming debris off of a floor. A fan  74  draws air and debris into the bin  50 , and a filter  54  keeps debris from the fan  74 . The fan  74  also creates suction at the port door  56  that can assist in keeping the port door closed. 
     Because the suction created during normal evacuation vacuum operation assists in keeping the port door open, the port door  56  can be configured so that part of the port door  56  swings in to a pocket volume independent from the vacuum chamber when the port door  56  is opened. The pocket volume can be in front of or behind the filter. Exhaust  76  flows out of the robot cleaner  10  as the air and debris is drawn in by the fan  74 . The port door  56  can be next to an exhaust vent. 
       FIG.  15 B  is a schematic side view of airflow through the example robotic cleaner  10  during evacuation to an evacuation station. The port door  56  is held open (e.g., by a poker.) Suction in the evacuation chamber  210  draws air and debris out of the bin  50 . Some air draw is permitted through the bin mouth  78 . 
       FIG.  16 A  is a schematic view of the inside of a bin of a robotic cleaner. The view is from the inside of the bin facing out. The bin includes a bin upper wall  66  and a filter  54 . The bin includes a port door  56  which is behind a vertical baffle  70  (and illustrated by dashed lines to indicate its location behind the baffle  70 ). Suction from the evacuation station draws air and debris through the port door  56 . The bevel  68  and vertical baffle  70  serve to redirect airflow through the bin and out the port door  56 . The air and debris flows around the filter  54  and out the port door  56  to the evacuation station. 
       FIG.  16 B  is a schematic view of a bin that does not show a motor or a filter. The port door  56  is located in the center of the bin. A bevel  68  and a baffle  70  serve to direct air to the rear wall and center. 
       FIG.  16 C  is a schematic view of the bin with the port door  56  on top of the bin. The port door  56  can be configured to open on contact with a poker of an evacuation connector as described above. 
       FIG.  17    is a schematic view of a bin having a port door  56  on the top of the bin. When the robotic cleaner docks, the poker  206  on the evacuation connector  202  opens the port door  56  to evacuate debris  1302  into the evacuation chamber  210 . Because the port door  56  is on the top of the bin, lateral movement from the robotic cleaner does not secure the seal between the evacuation connector  202  and the bin. A mating device, for example, a small wheel  220  and pivoted arm  222 , can apply pressure to the evacuation connector  202  to create a substantially airtight seal. The pivoted arm  222  can be configured to move about the wheel  220 , for example, by a servo motor actuated by a reed switch (e.g., a reed switch  214  that also actuates a vacuum to evacuate the bin).  FIG.  18    is a view of a bin for a robotic cleaner from the outside. The bin includes a port door  56  that is off center. The port door  56  can be opened, e.g., by a poker, for evacuation of debris within the bin. The bin also includes a vent where exhaust  76  can flow out of the bin while the robotic cleaner vacuums debris from the floor. 
       FIG.  19    is a view of a bin for a robotic cleaner from the inside looking out. The bin includes a filter  54  that curves around in front of a fan and an exhaust vent. The bin also includes a baffle  70  and a bevel  68  that shape airflow from a port door (behind the baffle) to allow evacuation of debris from the bottom of the bin. 
     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.