Patent Description:
Cleaning robots include mobile robots that perform desired cleaning tasks, such as vacuuming, in unstructured environments. Many kinds of cleaning robots are autonomous to some degree and in different ways. For example, an autonomous cleaning robot may be designed to automatically dock with an evacuation station for the purpose of emptying its cleaning bin of vacuumed debris.

<CIT>discloses a cleaning robot system including a robot and a robot maintenance station. The robot includes a robot body, a drive system, a cleaning assembly, and a cleaning bin carried by the robot body and configured to receive debris agitated by the cleaning assembly. The robot maintenance station includes a station housing configured to receive the robot for maintenance. The station housing has an evacuation passageway exposed to a top portion of the received robot. The robot maintenance station also includes an air mover in pneumatic communication with the evacuation passageway and a collection bin carried by the station housing and in pneumatic communication with the evacuation passageway. The station housing and the robot body fluidly connect the evacuation passageway to the cleaning bin of the received robot. The air mover evacuates debris held in the robot cleaning bin to the collection bin through the evacuation passageway.

The invention is defined in independent claim <NUM>, further preferred embodiments are described in the dependent claims.

According to the invention, an evacuation station includes a control system including one or more processing devices programmed to control evacuation of a debris bin of a mobile robot. The evacuation station includes a base to receive the mobile robot. The base includes an intake port to align to an exhaust port of the debris bin. The evacuation station further includes a canister to hold a bag to store debris from the debris bin and one or more conduits extending from the intake port to the bag through which debris is transported between the intake port and the bag. The cannister further comprises slots that align the bag with a bag interface end of the one or more conduits. The evacuation station also includes a motor that is responsive to commands from the control system to remove air from the canister and thereby generate negative air pressure in the canister to evacuate the debris bin by suctioning the debris from the debris bin.

In some examples, to control the amount of time to evacuate the debris bin based on the air pressure, the control system can be programmed to detect a steady state air pressure following a start of evacuation. The control system can be programmed to continue to apply the negative pressure for a predefined period of time during which the steady state air pressure is maintained and to send a command to stop operation of the motor.

The base can include electrical contacts that can mate to corresponding electrical contacts on the mobile robot to enable communication between the control system and the mobile robot. The control system can be programmed to receive a command from the mobile robot to initiate evacuation of the debris bin.

In some examples, the pressure sensor can include a Micro-Electro-Mechanical System (MEMS) pressure sensor.

In some examples, the intake port can include a rim that defines a perimeter of the intake port. The rim can have a height that is less than a clearance of an underside of the mobile robot, thereby allowing the mobile robot to pass over the rim. The intake port can include a seal inside of the rim. The seal can include a deformable material that is movable relative to the rim in response to the air pressure. In some examples, in response to the air pressure, the seal can be movable to contact, and conform to, a shape of the exhaust port of the debris bin. The seal can include one or more slits therein. In some examples, the seal can have a height that is less than a height of the rim and, absent the air pressure, is below an upper surface of the rim. In some examples, the one or more conduits can include a removable conduit extending at least partly along a bottom of the base between the intake port and the canister. The removable conduit can have a cross-sectional shape that transitions from at least partly rectangular adjacent to the intake port to at least partly curved adjacent to the canister. The cross-sectional shape of the removable conduit can be at least partly circular adjacent to the canister.

In some examples, the evacuation station can further include foam insulation within the canister. The motor can be arranged to draw air from the canister along split paths adjacent to the foam insulation leading to an exit port on the canister.

In some examples, the base can include a ramp that increases in height relative to a surface on which the evacuation station rests. The ramp can include one or more robot stabilization protrusions between a surface of the ramp and an underside of the mobile robot.

The canister includes a top that is movable between an open position and a closed position. The top can include a plunger that is actuated as the top is closed. The one or more conduits can include a first pipe and a second pipe within the canister. The first pipe can be stationary, and the second pipe can be movable into contact with the bag in response to movement of the plunger, thereby creating a path for debris to pass between the debris bin and the bag. The second pipe, when in contact with the bag, can make a substantially airtight seal to a latex membrane of the bag. The first pipe and the second pipe can be interfaced via flexible grommets. A cam mechanism can control movement of the second pipe based on movement of the plunger. The second pipe can be movable out of contact with the bag in response to moving the top into the open position.

In some examples, the control system can be programmed to control the amount of time to evacuate the debris bin based on the air pressure exceeding a threshold pressure of the canister. The threshold pressure can indicate that the bag has become full of the debris.

Advantages of the foregoing may include, but are not limited to, the following. The flap (also referred to as the door), by remaining enclosed within the exterior surface of the robot, will not contact objects in the environment when the flap (door) is in the open position. As a result, in some examples, if the flap is opened when the robot navigates along a floor surface, the flap does not contact the floor surface. The flap can be made of a flexible or compliant material or can be made of a rigid material such as a plastic.

The deformable material can last through several evacuation operations before being replaced. By being below the rim, the deformable material does not contact the mobile robot while the mobile robot is docking at the evacuation station and thus does not experience friction and contact forces that can damage the deformable material. Because the material is deformable, the material can improve air flow by creating an air-tight seal between the exhaust port of the debris bin and the intake port of the evacuation station. The seal can prevent air from leaking between the exhaust port and the intake port and can thus improve the efficiency of the negative air pressure used during the evacuation operation.

The removable conduit allows the user to easily clean debris stuck or entrained within the removable conduit. The cross-sectional shapes of the removable conduit allow the removable conduit to transport air (and, hence, the debris) without causing significant turbulence. The cross-sectional shapes of the removable conduit, by transitioning from a rectangular shape to a curved shape, further allow the base of the evacuation station to be angled to include a ramp having increasing height, which improves efficiency of evacuating debris from the debris bin.

The movable conduit allows the user to place a bag into the evacuation station without requiring the user to directly manipulate the bag to allow flow of air and debris to pass through the movable pipe into the bag. Rather, the user can simply place the bag in a canister of the evacuation station and close the top. The bag thus requires less user manipulation to operate with the evacuation station.

The controller can adaptively control the time in which it performs the evacuation operation (e.g., operates a motor of the evacuation station). The time of the evacuation operation can thus be minimized to improve power efficiency of the evacuation station and to reduce the time that the evacuation operation generates noise in the environment (caused by, for example, the motor of the evacuation station).

Any two or more of the features described in this specification, including in this summary section, can be combined to form implementations not specifically described herein.

The robots, or operational aspects thereof, described herein can be implemented as/controlled by a computer program product that includes instructions that are stored on one or more non-transitory machine-readable storage media, and that are executable on one or more processing devices to control (e.g., to coordinate) the operations described herein. The robots, or operational aspects thereof, described herein can be implemented as part of a system or method that can include one or more processing devices and memory to store executable instructions to implement various operations.

Described herein are example robots configured to traverse (or to navigate) surfaces, such as floors, carpets, or other materials, and to perform various cleaning operations including, but not limited to, vacuuming. Also described herein are examples of evacuation stations, at which the mobile robots can dock to evacuate debris stored in debris bins on the mobile robots. Referring to the example of <FIG>, a mobile robot <NUM> is configured to execute a cleaning operation to ingest debris as the mobile robot navigates about a surface <NUM> of an environment <NUM>. The ingested debris is stored in a debris bin <NUM> on the mobile robot <NUM>. The debris bin <NUM> becomes full after the mobile robot <NUM> has ingested a certain amount of debris.

After the debris bin has become full, the mobile robot can navigate to and dock at an evacuation station <NUM>. Generally, an evacuation station can additionally serve as, for example, a charging station and a docking station. The evacuation station includes a base station configured to remove debris from the debris bin, and to perform other functions vis-à-vis the mobile robot, such as charging. The evacuation station includes a control system, which can include one or more processing devices that are programmed to control operation of the evacuation station. In this example, the evacuation station <NUM> is controlled to generate negative air pressure to suction ingested debris out of the debris bin <NUM> and into the evacuation station <NUM>. As part of the evacuation operation, the debris is directed into a removable bag (not shown in <FIG>) housed in a canister <NUM> in the evacuation station <NUM>. Between the debris bin <NUM> and the bag, the evacuation station <NUM> includes conduits (not shown in <FIG>) that allow debris to pass from the debris bin <NUM> and into the bag. As described herein, the conduits can include a removable conduit that can be removed and cleaned, and a movable conduit that is controllable to move into, and out of, contact with the bag. Following evacuation, the mobile robot <NUM> can undock from the evacuation station <NUM>, and execute a new cleaning (or other) operation. The evacuation station <NUM> also includes one or more ports, to which the mobile robot <NUM> interfaces for charging.

<FIG> shows a cut-away side view of a mobile robot and an evacuation station of the type shown in <FIG>. In <FIG>, a mobile robot <NUM> is docked at an evacuation station <NUM>, thereby enabling the evacuation station <NUM> and the mobile robot <NUM> to communicate with one another (e.g., electronically and optically), as described herein. The evacuation station <NUM>, also depicted in <FIG>, includes a base <NUM> to receive the mobile robot <NUM> to enable the mobile robot <NUM> to dock at the evacuation station <NUM>. The mobile robot <NUM> may detect that its debris bin <NUM> is full, prompting the mobile robot <NUM> to dock at the evacuation station <NUM> so that the evacuation station <NUM> can evacuate the debris bin <NUM>. The mobile robot <NUM> may detect that it needs charging, also prompting the mobile robot <NUM> to return to the evacuation station <NUM> for charging.

Both the mobile robot <NUM> and the evacuation station <NUM> include electrical contacts. On the evacuation station <NUM>, the electrical contacts <NUM> are located along a rearward portion <NUM> of the base opposite to an intake port <NUM> located along a forward portion <NUM>. The electrical contacts <NUM> on the mobile robot <NUM> are located on a forward portion of the mobile robot <NUM>. Electrical contacts <NUM> on the mobile robot <NUM> mate to corresponding electrical contacts <NUM> on the base <NUM> when the mobile robot <NUM> is properly docked at the evacuation station <NUM>. The mating between the electrical contacts <NUM> and the electrical contacts <NUM> enables communication between the control system <NUM> on the evacuation station and a corresponding control system of the mobile robot <NUM>. The evacuation station <NUM> can initiate an evacuation operation and, in some cases, a charging operation, based on those communications. In other examples, the communication between the mobile robot <NUM> and the evacuation station <NUM> is provided over an infrared (IR) communication link. In some examples, the electrical contacts <NUM> on the mobile robot <NUM> are located on a back side of the mobile robot <NUM> rather than an underside of the mobile robot <NUM> and the corresponding electrical contacts <NUM> on the evacuation station <NUM> are positioned accordingly.

For example, when the electrical contacts <NUM>, <NUM> are properly mated, the evacuation station <NUM> can issue a command to the mobile robot <NUM> to initiate evacuation of the debris bin <NUM>. In some examples, the evacuation station <NUM> sends a command to the mobile robot <NUM> and will only evacuate if the mobile robot <NUM> completes a proper handshake (e.g., electrical contact between the electric contacts <NUM> and the electrical contacts <NUM>). For example, the control system <NUM> can send a communication to the mobile robot <NUM>, and receive a response to this communication from the mobile robot <NUM> and, in response, initiate an evacuation operation of the debris bin <NUM>. Additionally or alternatively, when the electrical contacts <NUM>, <NUM> are properly mated, the control system <NUM> can execute a charging operation to restore, wholly or partially, the power source of the mobile robot <NUM>. In other examples, when the electrical contacts <NUM>, <NUM> are properly mated, the mobile robot <NUM> can issue a command to the evacuation station <NUM> to initiate evacuation of the debris bin <NUM>. The mobile robot <NUM> can transmit the command to the evacuation station <NUM> through electrical signals, optical signals, or other appropriate signals.

Also, when the electrical contacts <NUM>, <NUM> are properly mated, the mobile robot <NUM> and the evacuation station <NUM> are aligned so that the evacuation station <NUM> can begin the evacuation operation. For example, the intake port <NUM> of the evacuation station <NUM> aligns with an exhaust port <NUM> of the debris bin <NUM>. Alignment between the intake port <NUM> and the exhaust port <NUM> provides for continuity of a flow path <NUM>, along which debris <NUM> travels between the debris bin <NUM> and a bag <NUM> in the evacuation station <NUM>. As described herein, the debris <NUM> is suctioned by the evacuation station <NUM> from the debris bin <NUM> into the bag <NUM>, where it is stored.

In this regard, the evacuation station includes a motor <NUM> connected to the canister <NUM>. The motor <NUM> is configured to draw air out of the canister <NUM>, and through bag <NUM>, which is air permeable. As a result, the motor <NUM> can create a negative air pressure within the canister <NUM>. The motor <NUM> responds to commands from the control system <NUM> to draw air out of the canister <NUM>. The motor <NUM> expels the air drawn out of the canister <NUM> through an exit port <NUM> on the canister <NUM>. As noted, the removal of air generates negative air pressure in the canister <NUM>, which evacuates the debris bin <NUM> by generating an air flow along the flow path <NUM> that suctions the debris <NUM>. In this example, the debris <NUM> moves along flow path <NUM> from the debris bin <NUM>, through a door unit (not shown) on the debris bin <NUM>, through the exhaust port <NUM> on the debris bin <NUM>, through intake port <NUM> on the base <NUM>, through multiple conduits 230a, 230b, 230c in the evacuation station <NUM>, and into the bag <NUM>.

Air is expelled by the motor <NUM> through an exhaust chamber <NUM> housing the motor <NUM> and through the exit port <NUM> into the environment. The bag <NUM> can be an air permeable filter bag that can receive the debris <NUM> travelling along the flow path <NUM> - which can include flows of, for example, air and debris <NUM> - and separate the debris <NUM> from air. The bag <NUM> can be disposable and formed of paper, fabric, or other appropriately porous material that allows air to pass through but traps the debris <NUM> within the bag <NUM>. Thus, as the motor <NUM> removes air from the canister <NUM>, the air passes through the bag <NUM> and exits through the exit port <NUM>.

The evacuation station <NUM> also includes a pressure sensor <NUM>, which monitors the air pressure within the canister <NUM>. The pressure sensor <NUM> can include a Micro-Electro-Mechanical System (MEMS) pressure sensor or any other appropriate type of pressure sensor. A MEMS pressure sensor is used in this implementation because of its ability to continue to accurately operate in the presence of vibrations due to, for example, mechanical motion of the motor <NUM> or motion from the environment transferred to the evacuation station <NUM>. The pressure sensor <NUM> can detect changes in air pressure in the canister <NUM> caused by the activation of the motor <NUM> to remove air from the canister <NUM>. The length of time for which evacuation is performed may be based on the pressure measured by the pressure sensor <NUM>, as described with respect to <FIG>.

<FIG> depicts an example graph <NUM> of air pressure <NUM> generated over a period of time <NUM> in response to the removal of air from canister <NUM>. The air pressure <NUM>, before activation by motor <NUM>, can be atmospheric air pressure. The initial activation of the motor <NUM> can cause an initial dip <NUM> in the air pressure <NUM>. This initial dip <NUM> can occur due to a cracking pressure needed to initially open a flap or door of the door unit on the debris bin. More particularly, the initial dip <NUM> can be associated with the flap including a biasing mechanism that requires a first air pressure to move initially from a closed position to an open position that is higher than a second air pressure to maintain the flap in the open position.

As the motor <NUM> continues removing air and drawing debris <NUM> into the bag <NUM>, fluctuations <NUM> may occur in the air pressure <NUM> due to the movement of the debris <NUM> through the flow path <NUM>. That is, the debris <NUM> can cause partial occlusions of the flow path <NUM> that can cause the air pressure <NUM> to experience the fluctuations <NUM>. The partial occlusions can cause the fluctuations <NUM> to include decreases in the air pressure <NUM>. In some cases, during the evacuation operation, the air pressure <NUM> can clear the partial occlusions and decrease resistance to the air flow. The fluctuations <NUM> may thus include increase in the air pressure <NUM> after the partial occlusions are cleared. In addition, movement of the debris <NUM> within the bag <NUM> can cause changes in flow characteristics of the air, also resulting in the fluctuations <NUM>. As the debris <NUM> continues filling the bag <NUM>, the air pressure <NUM> increases due to the debris <NUM> impeding air flow through the canister <NUM>.

When the debris <NUM> is mostly or completely evacuated from the debris bin <NUM>, the bag <NUM> does not continue to fill with debris, thus resulting in a steady state <NUM> for the air pressure <NUM>. In this context, steady state <NUM> may include a constant pressure or fluctuations relative to a constant pressure that do not exceed a certain percentage, e.g., <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, etc., over the course of a period of time. The control system <NUM> can determine that the air pressure <NUM> has reached the steady state <NUM> by monitoring the air pressure <NUM> for a predefined period of time <NUM> following a start of evacuation. The air pressure <NUM> can be detected by the pressure sensor <NUM> which, in turn, can generate and transmit air pressure signals to the control system <NUM> for the processing. The control system <NUM> may use these pressure signals to determine when to terminate debris bin evacuation. In this regard, it can be advantageous to reduce the amount of evacuation time, since evacuation can be a relatively noisy process, and since evacuation time cuts-into cleaning time. Furthermore, in some cases, the majority of debris <NUM> is suctioned from the debris bin <NUM> within a fraction of the overall programmed evacuation time, making at least some of that time unnecessary. In some instances, the programmed evacuation time is <NUM> seconds, whereas the majority of debris is actually evacuated from the debris bin <NUM> within <NUM> seconds.

As shown in <FIG>, upon entry into the steady state condition <NUM>, the control system <NUM> continues to control the motor <NUM> to cause the motor <NUM> to continue to apply the negative air pressure. This negative air pressure is applied for the predefined period of time <NUM>, during which the air pressure <NUM> is maintained within a predefined range <NUM> (e.g., a range defined by a two-sided hysteresis). After that predefined period of time <NUM>, if the air pressure <NUM> remains stable (e.g., within the predefined range <NUM>), the control system <NUM> sends commands to stop operation of the motor <NUM>, thereby terminating evacuation. The motor <NUM> then stops removing air from the canister <NUM>, causing the air pressure <NUM> to return to atmospheric pressure. The predefined period of time <NUM> can be, for example, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, etc. The predefined range <NUM> can be, for example, plus or minus <NUM> Pa, <NUM> Pa, <NUM> Pa, <NUM> Pa, etc. The predefined period of time <NUM> and the predefined range can be stored on a memory storage element operable with the control system <NUM>.

In some implementations, the steady state air pressure <NUM> can decrease below a threshold pressure <NUM>, which indicates that the bag <NUM> has become substantially full of debris. In some implementations, as atmospheric conditions, debris, and other conditions will vary, the trend in the steady state air pressure <NUM> over multiple evacuations would be used to indicate that the bag <NUM> has become substantially full of debris. A combination of a threshold pressure <NUM> and the trend of the steady state air pressure <NUM> is used in some implementations. The steady state air pressure <NUM> decreases as the bag <NUM> fills and it becomes more difficult to pull air through the bag <NUM>. The threshold pressure <NUM> can be pre-determined (e.g., stored in a memory storage element accessible by the control system <NUM>) or it can be adjusted by the control system <NUM> based on a baseline reading of the steady state air pressure <NUM> when a new bag <NUM> is installed. The control system <NUM> can determine, for example, when the steady state air pressure <NUM> is below the threshold pressure <NUM>, the trend in the steady state air pressure <NUM> over multiple evacuations is sufficiently sloped, or any combination thereof, and can then transmit instructions for an operation in response to the air pressure <NUM> exceeding the threshold pressure <NUM>. For example, the control system <NUM> can transmit commands to the motor <NUM> to end evacuation of the debris <NUM>, thus causing the air pressure <NUM> to return to atmospheric pressure. The threshold pressure <NUM> can between, for example, 600Pa to <NUM> Pa, but this will depend on conditions in the system and environment. The threshold pressure <NUM> can indicate percent volume of the bag <NUM> occupied by the debris <NUM> between, for example <NUM>% and <NUM>%. Upon detecting that the bag <NUM> is full, the control system <NUM> can also output instructions to a computer system, such as a server, which maintains a user account and which can notify the user that the bag is full and needs to be changed. For example, the server can output the information to an application ("app") on the user's mobile device, which the user can access to monitor their home system. In some examples, a second threshold pressure (e.g., a notification pressure) can be used to notify the user that the bag <NUM> is nearing the full state and a limited number of additional evacuations will be possible prior to replacement of the bag <NUM>. Thus, the system can notify the user and allow the user to replace the bag <NUM> prior to the bag <NUM> being too full to allow evacuation of the robot bin.

By monitoring the air pressure <NUM> in the canister <NUM> using the pressure sensor <NUM>, the control system <NUM> can adaptively control an amount of evacuation time <NUM> that the control system <NUM> operates the motor <NUM> and, therefore, the amount of time that evacuation of the debris bin <NUM> occurs. For example, the point in time when the air pressure <NUM> exceeds the threshold pressure <NUM> and/or the point in time when the air pressure <NUM> is maintained within the predefined range <NUM> for the period of time <NUM> can dictate when evacuation ends. In some implementations, the control system <NUM> can control the evacuation time <NUM> to be between <NUM> seconds and <NUM> seconds. The air pressure <NUM>, and thus the evacuation time <NUM>, can depend on a number of factors such as, but not limited to, an amount of debris stored in the debris bin <NUM> and flow characteristics caused by, e.g., the size, viscosity, water content, weight, etc. of the debris <NUM>.

<FIG> shows a flow chart of an example process <NUM> in which a control system (e.g., the control system <NUM>) operates a motor (e.g., the motor <NUM>) of an evacuation station (e.g., the evacuation station <NUM>) based on electrical contact signals and air pressure (e.g., the air pressure <NUM>) in a canister (e.g., the canister <NUM>) of the evacuation station.

At the start of the process <NUM>, the control system receives (<NUM>) electrical contact signals. The electrical contact signals indicate that a mobile robot is docked at the evacuation station. In some examples, the electrical contact signals can indicate that electrical contacts of a mobile robot are in electrical and physical contact with electrical contacts of the evacuation station.

After receiving the electrical contact signals, the control system sends (<NUM>) optical start signals to initiate evacuation via, for example, an optical communication link. In some cases, the mobile robot transmits the optical start signals using the optical communication link. Because the electrical contacts of the mobile robot are in contact with the electrical contacts of the evacuation station, the mobile robot is properly aligned with the evacuation station for the evacuation station to initiate the evacuation process by transmitting the optical start signals directly to the mobile robot. The mobile robot acknowledges the start optical signal with an acknowledgement optical signal to the evacuation station before the control system begins evacuation.

The control system then transmits (<NUM>) commands to begin evacuation. The control system can transmit (<NUM>) the commands to begin evacuation after receiving the optical acknowledgement signal from the mobile robot to begin the evacuation. In some examples, the evacuation station detects the received (<NUM>) electrical contact signals and transmits (<NUM>) commands to begin the evacuation after detecting the received (<NUM>) electrical contact signals. The evacuation station thus does not receive optical start signals from the mobile robot to begin evacuation. In some implementations, the control system does not receive (<NUM>) electrical contact signals when the electrical contacts mate. The controller of the mobile robot can receive the electrical contact signals and then transmit the optical start signals to the control system in response to the electrical contact signals.

The commands transmitted (<NUM>) by the control system can instruct the motor to activate as described herein. Specifically, the motor suctions air out of the canister of the evacuation station to generate a negative air pressure within the canister. The resulting negative air pressure extends along the flow path and into the robot's debris bin, causing suction of the debris from the robot's debris bin, through the flow path, and into an air permeable bag held in the canister.

The control system continues transmitting (<NUM>) the commands, thereby continuing operation of the motor and evacuation of debris. During operation of the motor, the control system can modify the power delivered to the motor to increase or decrease the amount of negative air pressure generated within the canister.

The control system continues to receive (<NUM>) air pressure signals from the pressure sensor in the canister while evacuation continues. The measured air pressure signals vary due to variations in amounts of debris within the bag, blockage of the flow path, or the like.

Based on the air pressure signals, the control system determines (<NUM>) whether the air pressure within the canister has reached steady state. To determine (<NUM>) whether the air pressure has reached steady state, the control system determines that it has received air pressure signals indicating a pressure within a defined range for at least predefined amount of time. If the control system determines that the air pressure has been in the steady state for the predefined amount of time, the control system can transmit (<NUM>) commands to end evacuation. If the control system determines (<NUM>) that the air pressure has not reached steady state air pressure, the control system can continue transmitting (<NUM>) commands for evacuation, receive (<NUM>) air pressure signals, and determine (<NUM>) whether to transmit (<NUM>) instructions to end evacuation. In other examples, the control system can have a pre-set evacuation time (length of evacuation). In such situations, the control system does not determine the completion of evacuation based on the pressure sensor signals.

The system also determines (<NUM>) whether the steady state air pressure is (a) indicative of a non-full bag condition (b) in a range for notification of a bag that is reaching a full state, or (c) indicative of a bag full condition based on a comparison of the steady state air pressure to a threshold. If the control system determines that the air pressure exceeds both the notification and bag full threshold pressures, the control system awaits (<NUM>) the next evacuation process. If the control system determines (<NUM>) that the air pressure is below the notification threshold but above the bag full threshold pressure, the control system transmits (<NUM>) a notification to the user indicating that the bag is close to being full. If the control system determines (<NUM>) that the air pressure is below the bag full threshold pressure, the control system transmits (<NUM>) a notification to the user indicating that the bag is full and prohibits (<NUM>) further evacuation of the bin until the bag is replaced.

As described herein, motor <NUM> generates negative air pressure in the canister <NUM> to create air flow along the flow path <NUM> to carry the debris <NUM> from the debris bin <NUM> to the bag <NUM> held in the canister <NUM>. And, as described herein with respect to, for example, <FIG> and <FIG>, the control system <NUM> uses air pressure monitored by the pressure sensor <NUM> to determine the evacuation time <NUM> that the control system <NUM> activates the motor <NUM> to evacuate the bag <NUM>. Thus, sealing the air pressure of the canister <NUM> and the multiple conduits 230a, 230b, 230c from the environment can be advantageous so that the motor <NUM> operates more efficiently and so that the air pressure detected by the pressure sensor <NUM> can predictably inform the control system <NUM> of status of the evacuation operation.

In some examples as shown in <FIG>, <FIG>, the intake port <NUM> of the evacuation station <NUM> includes a rim <NUM> defining a perimeter of the intake port <NUM> and a seal <NUM> inside of the rim <NUM>. The seal <NUM> is disposed within the intake port <NUM>, and is below the rim <NUM> (e.g., between <NUM> - <NUM> below the rim). However, the seal <NUM> is not fixed relative to the intake port <NUM> or the rim <NUM>, and is movable relative thereto, e.g., in response to negative air pressure experienced through the flow path. The rim <NUM> can be located at a forward portion <NUM> of the evacuation station <NUM> so that, when the mobile robot <NUM> docks at the evacuation station <NUM>, the intake port <NUM> aligns with the exhaust port <NUM> of the debris bin <NUM>.

In the absence of the negative air pressure such as when the mobile robot <NUM> is not docked at the evacuation station <NUM>, as shown in <FIG>, the seal <NUM> is protected from contact and frictional forces due to the mobile robot <NUM> docking at the evacuation station <NUM>. The geometry of the rim <NUM> and the seal <NUM> can reduce wear of the rim <NUM> and the seal <NUM> when the mobile robot <NUM> moves over the rim <NUM> to dock at the evacuation station <NUM>. A height <NUM> of the rim <NUM> is greater than a height <NUM> of the seal <NUM> such that, when the mobile robot <NUM> passes over the rim <NUM>, the underside of the mobile robot <NUM> does not contact the seal <NUM>. In the absence of the negative air pressure, the height <NUM> of the seal <NUM> is thus below an upper surface <NUM> of the rim <NUM>. The height <NUM> can also be less than a clearance <NUM> of an underside <NUM> of the mobile robot <NUM>, as shown in <FIG>. As a result, the mobile robot <NUM> can pass over the rim <NUM> when the mobile robot <NUM> docks at the evacuation station <NUM>.

The seal <NUM> may be made of a deformable material that can be movable relative to the rim <NUM> in response to forces caused by, for example, the negative air pressure generated by the motor <NUM>. The material can be, for example, a thin elastomer. In some implementations, the elastomer ethylene propylene diene monomer (EPDM) rubber, silicone rubber, polyether block amides, Chloropene rubber, Butyl rubber, among other elastomeric materials. In the presence of the negative air pressure in the flow path during an evacuation operation, the seal <NUM> can respond to the negative air pressure generated during the evacuation operation by moving upward, toward the mobile robot <NUM>, and deforming to form an air-tight seal with the mobile robot <NUM>. In an example, the seal <NUM> conforms to a shape of the mobile robot <NUM> in an area surrounding the exhaust port <NUM> of the debris bin <NUM>. The seal <NUM> has a width that is relative to the separation between the evacuation station <NUM> and the mobile robot <NUM> when the mobile robot <NUM> is located on the evacuation station <NUM> such that the seal <NUM> can extend upwardly to contact the underside <NUM> of the mobile robot <NUM> (e.g., <NUM> to <NUM>).

As shown in <FIG>, in some examples, the seal <NUM> includes one or more slits <NUM> that allow the seal <NUM> to deform upward at corners of the seal <NUM> without generating excessive hoop stress in the seal <NUM> due to the upward deformation. The slit <NUM> can thus increase a lifespan of the seal <NUM> and increase the number of or duration of evacuation operations executed by the evacuation station <NUM>.

The seal <NUM> and the rim <NUM> cooperate to provide an air-tight seal between the debris bin <NUM> and the evacuation station <NUM> that is durable. In some implementations, the seal <NUM> can be replaceable. A user can remove the seal <NUM> from the rim <NUM> and replace the seal <NUM>.

In some implementations, each of the conduits 230a, 230b, 230c, in addition to providing a continuous flow path <NUM> for transporting debris, can include features that improve ease of operation, manipulation, and cleaning of the evacuation station <NUM>. As shown in <FIG> and <FIG>, for example, the conduit 230a extends partly along a bottom <NUM> of the base <NUM>. In some cases, the conduit 230a extends partly upward (e.g., along the z-axis) along the evacuation station <NUM>, connecting the debris bin <NUM> to the conduit 230b. The conduit 230b extends upward from the conduit 230a, connecting the conduit 230a to the conduit 230c. Flexible grommets <NUM> connect the conduit 230b to the conduit 230c. The conduit 230c extends upward from the conduit 230b and connects the conduit 230c to the bag <NUM>.

The conduit 230a can be sized, and dimensioned, such that a ramp <NUM>, shown in <FIG> and described herein, can have a lower height along the forward portion <NUM>. In an example, the conduit 230a can have a cross-sectional shape that transitions from at least partly rectangular to at least partly curved. As shown in <FIG>, a portion 1000a of the conduit 230a adjacent to the intake port <NUM> can have a cross-sectional shape 1005a that is rectangular, and a portion 1000c of the conduit 230a adjacent to the canister <NUM> can have a cross-sectional shape 1005c that is either circular or at least partly curved. In some implementations, the cross-sectional shape 1005c is partly circular. A portion 1000b of the conduit 230a can have a transitional cross-sectional shape 1005b that gradually transitions from the cross-sectional shape 1005a to the cross-sectional shape 1005c to reduce sharp geometries within the conduit 230a. The transitional cross-sectional shape 1005b can be partly curved, partly rectangular, partly circular, or combinations thereof. The cross-sectional shape 1005a can have a smaller height than the cross-sectional shape 1005b and the cross-sectional shape 1005c so that the ramp <NUM> can have increasing height going from the forward portion <NUM> toward the rearward portion <NUM>.

The conduit 230a can include cross-sectional areas that remain constant between the intake port <NUM> and the conduit 230b to facilitate non-turbulent air flow through the flow path <NUM>. The cross-sectional area of the cross-sectional shapes 1005a, 1005b, 1005c can be substantially constant throughout the length of the conduit 230a to reduce influence of geometry on flow characteristics through the conduit 230a.

The conduit 230a can be a transparent, removable conduit and/or a replaceable conduit in order to facilitate cleaning the debris <NUM> from the evacuation station <NUM>. A user can remove the conduit 230a and clean an interior of the conduit 230a to remove, for example, debris clogs trapped within the conduit 230a. The conduit 230a can be fastened to the base <NUM> using removable fasteners, such as, for example, screws, reversible snap fits, tongue and groove joints, and other fasteners. The user can remove the fasteners and then remove the conduit 230a from the base <NUM> to clean the interior of the conduit 230a.

The conduits 230b, 230c includes pipes that move relative to one another. In an example, the conduit 230b is a stationary pipe, and the conduit 230c is a movable pipe. Referring to <FIG>, a flexible grommet <NUM> provides a flexible interface between the conduit 230b and the conduit 230c. In some implementations, the evacuation station <NUM> can include one or more flexible grommets <NUM>. The conduit 230c pivots at the interface between the conduit 230c and the conduit 230b because of the flexibility of the grommet <NUM>.

The conduit 230c can be moved into position to interface with the bag <NUM> to establish the continuous flow path <NUM> between the debris bin <NUM> and the bag <NUM>. In some implementations, as shown in <FIG>, to move the conduit 230c relative to the conduit 230b, the evacuation station <NUM> can include a cam mechanism <NUM> (shown in <FIG>) and a plunger <NUM> located within the canister <NUM>. The cam mechanism <NUM> can include levers, cams, shuttles, and other components to transfer kinematic motion from the plunger <NUM> to the conduit 230c. The plunger <NUM> can be an elongate component that moves axially (e.g., along the z-axis 1506Z of <FIG>).

The cam mechanism <NUM> controls movement of the conduit 230c based on movement of the plunger <NUM> of the evacuation station <NUM>. In this regard, a top <NUM> of the canister <NUM> can be movable between an open position (<FIG>), and a closed position (<FIG>). Movement of the top <NUM> from the open position to the closed position actuates the plunger <NUM> which in turn causes the cam mechanism <NUM> to move the conduit 230c relative to the conduit 230b. Moving the top <NUM> from the open position (<FIG>) to the closed position (<FIG>) causes the conduit 230c to move from the receded position (circled in <FIG>) in which the conduit 230c does not interface with the bag <NUM> to the extended position (circled in <FIG>) in which the conduit 230c does interface with the bag <NUM>. Thus, the conduit 230c can be movable out of contact with the bag <NUM> in response to moving the top <NUM> into the open position (<FIG>). In addition, the conduit 230c can be movable into contact with the bag <NUM> in response to movement of the plunger <NUM>. When the conduit 230c is contact with the bag <NUM>, the conduit 230c can make a substantially airtight seal to a latex membrane <NUM> of the bag <NUM>. As a result, the conduit 230c can create a path (e.g., the continuous flow path <NUM> through the conduits 230a, 230b, 230c) for the debris <NUM> and the air to pass between the debris bin <NUM> and the bag <NUM>. In some cases, the canister can include alignment features, such as slots, that align the bag <NUM> with the bag interface end <NUM> of the conduit 230c.

The mechanisms of the top <NUM> and the conduit 230c may provide the user a convenient way to load the bag <NUM> in the evacuation station <NUM>, and to remove the bag from the evacuation station. Before the bag <NUM> is placed into the canister <NUM>, the user can open the top <NUM> (<FIG>), causing the conduit 230c to move into the receded position (<FIG>). The user can then place the bag <NUM> into the canister <NUM> such that the bag <NUM> is aligned with the conduit 230c. The user can close the top <NUM> (<FIG>), causing the conduit 230c to move into the extended position (<FIG>). The bag interface end <NUM> of the conduit 230c can connect with the bag <NUM>, thus interfacing the bag <NUM> with the conduit 230c. Thus, the user can incorporate the bag <NUM> into the flow path <NUM> without significantly manually manipulating the bag <NUM> and the bag interface end <NUM> of the conduit 230c.

As described herein, while the debris <NUM> is trapped within the bag <NUM>, air continues flowing through the bag <NUM> into the exhaust chamber <NUM>. As shown in <FIG>, the exhaust chamber <NUM> includes a motor housing <NUM> that houses the motor <NUM> (not shown in <FIG>). Thus, the air exiting through the exit port <NUM> carries energy associated with noise of the motor <NUM>.

The exhaust chamber <NUM> can include features to reduce or decrease the amount of noise caused by the motor <NUM>. As shown in <FIG>, in the exhaust chamber <NUM> of the canister <NUM>, the air takes two split flow paths 1405a and 1405b out through the exit port <NUM>. The split flow paths 1405a, 1405b exit through a portion <NUM> of the motor housing <NUM>. The portion <NUM> faces away from the exit port <NUM> to extend the distance that air travels between the motor <NUM> and the exit port <NUM>. In some cases, the canister <NUM> further includes foam insulation <NUM> adjacent the split flow paths 1405a, 1405b that absorb sound as the air travels along the split flow paths 1405a, 1405b. The split flow path 1405a, 1405b and the foam insulation <NUM> can together reduce the noise caused by the motor <NUM>.

The evacuation station <NUM> can include additional features that affect evacuation operation of the evacuation station <NUM>. In an example, the ramp <NUM>, as shown in <FIG> and <FIG>, assists with guiding debris <NUM> towards the intake port <NUM>. The ramp <NUM> forms an angle <NUM> with a surface <NUM> on which the evacuation station <NUM> rests. Thus, the ramp <NUM> increases in height relative to the surface <NUM>. The angle <NUM> allows gravity to cause debris <NUM> residing in the debris bin <NUM> to gather at toward the back of the debris bin <NUM> closer to the exhaust port <NUM> of the debris bin <NUM> when the mobile robot <NUM> docks at the evacuation station <NUM>. During evacuation, as the negative air pressure loosens and suctions the debris <NUM>, gravity also assists in moving the debris <NUM> toward the exhaust port <NUM> into the flow path <NUM>. Thus, the angle of the ramp <NUM> can expedite the evacuation operation.

In some examples, the evacuation station <NUM> can include features to assist in proper alignment and positioning of the mobile robot <NUM> relative to the evacuation station <NUM>. For horizontal alignment (e.g., alignment along a y-axis 1506Y shown in <FIG>) of the mobile robot <NUM> with the evacuation station <NUM>, the ramp <NUM> can include wheel ramps <NUM> (shown in <FIG>) that are sized and shaped appropriately to receive wheels of the mobile robot <NUM>. When the mobile robot <NUM> navigates up the ramp <NUM>, the wheels of the mobile robot <NUM> align with the wheel ramps <NUM>. The wheel ramps <NUM> can include traction features <NUM> (shown in <FIG>) that can increase traction between the mobile robot <NUM> and the ramp <NUM> so that the mobile robot <NUM> can navigate up the ramp <NUM> and dock at the evacuation station <NUM>.

For vertical alignment (e.g., alignment along a z-axis 1506Z shown in <FIG>), the evacuation station <NUM> can include, as shown in <FIG>, a robot stabilization protrusion <NUM> on the mobile robot <NUM> that contacts a robot stabilization protrusion <NUM> on the ramp <NUM>. When the mobile robot <NUM> docks at the evacuation station <NUM>, the robot stabilization protrusions <NUM>, <NUM> thus can maintain contact between the electrical contacts <NUM> of the mobile robot <NUM> with the electrical contacts <NUM> of the evacuation station <NUM>. The robot stabilization protrusion <NUM> on the ramp <NUM> is located between a surface <NUM> on the ramp <NUM> and the underside <NUM> of the mobile robot <NUM>. In some implementations, the ramp <NUM> can include two or more robot stabilization protrusions <NUM> and/or two or more robot stabilization protrusions <NUM>.

During the evacuation operation, the negative air pressure results in a force applied to a rear portion <NUM> of the mobile robot <NUM>. The force can cause motion of portions of the mobile robot <NUM> along the z-axis 1506Z. For example, a frontward portion (not shown in <FIG>) may lift off of the ramp <NUM>, thus potentially resulting in misalignment between the electrical contacts <NUM> and the electrical contacts <NUM>. Contact between the robot stabilization protrusion <NUM> and the robot stabilization protrusion <NUM> can reduce motion of the mobile robot <NUM> caused by the force resulting from negative air pressure that can cause the mobile robot <NUM> to lift off of the ramp <NUM>. As a result, the electrical contacts <NUM> can remain in contact with the electrical contacts <NUM> so that the evacuation operation continues uninterrupted.

The evacuation stations (e.g., the evacuation station <NUM>) described herein can be used with a number of types of mobile robots that include bins to store debris. The evacuation stations can evacuate the debris from the bins.

In an example, as shown in <FIG>, a mobile robot <NUM> can be a robotic vacuum cleaner that ingests debris from a floor surface. The mobile robot <NUM> includes a body <NUM> that navigates about a floor surface <NUM> using drive wheels <NUM>. A caster wheel <NUM> and the drive wheels <NUM> support the body <NUM> over the floor surface <NUM>. The drive wheels <NUM> and the caster wheel <NUM> can support the body <NUM>, and hence a debris bin <NUM> (e.g., the debris bin <NUM>), such that the debris bin <NUM> is supported a clearance distance <NUM> between <NUM> and <NUM> above the surface <NUM>.

The mobile robot <NUM> ingests debris <NUM> (e.g., the debris <NUM>) using a suction mechanism <NUM> to generate an air flow <NUM> that causes the debris <NUM> on the floor surface <NUM> to be propelled into the debris bin <NUM>. The suction mechanism <NUM> can thus suction debris <NUM> from the floor surface <NUM> into the debris bin <NUM> during traversal of the floor surface <NUM>. The body <NUM> supports a front roller 1614a and a rear roller 1614b that cooperate to retrieve debris <NUM> from the surface <NUM>. More particularly, the rear roller 1614b rotates in a counterclockwise sense CC, and the front roller 1614a rotates in a clockwise sense C. As the front roller 1614a and the rear roller 1614b rotate, the mobile robot <NUM> ingests the debris and the air flow <NUM> causes the debris <NUM> to flow into the debris bin <NUM>. The debris bin <NUM> includes a chamber <NUM> to hold the debris <NUM> received by the mobile robot <NUM>.

A control system <NUM> (implemented, e.g., by one or more processing devices) can control operation of the mobile robot <NUM> as the mobile robot <NUM> traverses the floor surface <NUM>. For example, during a cleaning operation, the control system <NUM> can cause motors (not shown) to rotate the drive wheels <NUM> to cause the mobile robot <NUM> to move across the floor surface <NUM>. The control system <NUM>, during the cleaning operation, can further activate motors to cause rotation of the front roller 1614a and the rear roller 1614b and to activate the suction mechanism <NUM> to retrieve the debris <NUM> from the floor surface <NUM>.

The debris bin <NUM> provides an interface between the chamber <NUM> and an evacuation station (e.g., the evacuation station <NUM>) such that the evacuation station can evacuate the debris <NUM> stored in the chamber <NUM> and the debris bin <NUM>. The debris bin <NUM> includes an exhaust port <NUM> (e.g., the exhaust port <NUM>) through which debris <NUM> can exit the chamber <NUM> of the debris bin <NUM> into the evacuation station.

In <FIG>, a bin door <NUM> is open so that an evacuation door unit <NUM> is visible. During the cleaning operation and the evacuation operation, the bin door <NUM> is typically closed. The user can open the bin door <NUM> by rotating the bin door <NUM> about hinges <NUM> to manually empty debris <NUM> from the debris bin <NUM>.

As shown in <FIG>, the evacuation door unit <NUM> of the debris bin <NUM> can include a flap (also referred to as a door) <NUM> that opens and closes to control flow of the debris <NUM> between the chamber <NUM> and external devices. The door unit <NUM> includes a support structure <NUM> disposed within the debris bin <NUM>. The support structure <NUM> can be semi-spherical. The door unit <NUM> is located over the exhaust port <NUM>. The flap <NUM> is configured to move between a closed position shown in <FIG> and an open position shown in <FIG>. The flap <NUM> is mounted on the support structure <NUM>. The flap <NUM> moves from the closed position to the open position in response to a difference in air pressure at the exhaust port and within the debris bin <NUM>. As described herein, the evacuation station can generate a negative air pressure, thus causing the air in the debris bin <NUM> to generate an air pressure that moves the flap <NUM> from the closed position (<FIG>) to the open position (<FIG>). In the closed position (<FIG>), the flap <NUM> blocks air flow between the debris bin <NUM> and the environment. In the open position (<FIG>), the flap <NUM> provides a path <NUM> between the debris bin <NUM> and the exhaust port <NUM>.

The door unit <NUM> can include a biasing mechanism that biases the flap <NUM> into the closed position (<FIG>). In an example, as shown in <FIG>, which depicts an underside of the door unit <NUM>, a torsion spring <NUM> biases the flap <NUM> into the closed position (<FIG>). The flap <NUM> rotates about a hinge <NUM> having a rotational axis <NUM>, and the torsion spring <NUM> applies force that generates a torque about the axis <NUM> that biases the flap <NUM> into the closed position (<FIG>). The hinge <NUM> connects the flap <NUM> to the support structure <NUM> of the door unit <NUM>.

In another example, as shown in <FIG>, which depicts the underside of the door unit <NUM>, and <FIG>, which depicts a top perspective view of the door unit <NUM> within the debris bin <NUM>, a leaf spring <NUM> biases the flap <NUM> into the closed position. The flap <NUM> rotates about a flexible coupler <NUM> that has an approximate rotational axis, and the leaf spring <NUM> applies force that generates a torque about the rotational axis that biases the flap into the closed position. The flexible coupler <NUM> acts like a hinge which does not have any relative rotation of parts at a mechanical interface, like a mechanical hinge.

In another example, as shown in <FIG> which depicts a cross-sectional view of the door unit <NUM> and a relaxing spring <NUM> of the door unit <NUM> that biases the flap <NUM> into the closed position. In this example, the spring force that holds the flap <NUM> shut relaxes as the flap <NUM> opens. Because the spring force relaxes as the flap <NUM> opens, the magnitude of the pressure wave that the debris bin sees during evacuation is determined by the cracking pressure on the flap <NUM>. The amount of material evacuated is affected by how wide the flap <NUM> opens. With flow, after the flap <NUM> opens, the pressure drops. The relaxing spring <NUM> is believed to provide a spring with a high crack force but a low dwell force. The flap <NUM> is designed to be closed by a sliding interaction between the spring <NUM> and a lever arm <NUM> as the flap <NUM> opens, the contact point slides up and shortens the lever arm <NUM> between the spring <NUM> and a flap pivot <NUM> and thus reduces the moment on the flap <NUM>. As a result, a smaller force on the flap <NUM> (e.g., from pressure) is required to maintain the flap <NUM> open. In some examples, the sliding could be aided by a roller on the flap <NUM> along the lever arm <NUM> to reduce sliding friction.

During the evacuation operation, the air pressure generated against the flap <NUM> causes the flap <NUM> to overcome the biasing force exerted by the biasing mechanism (e.g., the torsion spring <NUM>, the leaf spring <NUM>, the relaxing spring <NUM>), thus causing the flap <NUM> to move from the closed position (<FIG>) to the open position (<FIG>).

During the cleaning operation, the flap <NUM> of the door unit <NUM> closes the exhaust port <NUM> such that the debris <NUM> cannot escape through the exhaust port <NUM>. As a result, the debris <NUM> ingested into the debris bin <NUM> remains in the chamber <NUM>. During an evacuation operation as described herein, air pressure causes the flap <NUM> of the door unit <NUM> to open, thereby exposing the exhaust port <NUM> such that the debris <NUM> in the chamber <NUM> can exit through the exhaust port <NUM> into the evacuation station.

<FIG> depict the flap <NUM> in the closed position. <FIG>, <FIG> show the same perspectives of the door unit <NUM>, as <FIG>, and <FIG>, respectively, but the flap <NUM> is in the open position. A biasing mechanism <NUM> (e.g., a biasing mechanism that includes the torsion spring <NUM> of <FIG>, the leaf spring <NUM> of <FIG>, or the relaxing spring <NUM> of <FIG>), biases the flap <NUM> into the closed position (<FIG>). As described herein, the negative air pressure causes the flap <NUM> to move into the open position (<FIG>). The flap <NUM> in the open position (<FIG>) forms the path <NUM>, which allows air and thus the debris <NUM> to flow through the exhaust port <NUM> into the evacuation station.

The flap <NUM> in the closed position in <FIG> and in the open position in <FIG> remain within an exterior surface <NUM> (e.g., a bottom surface) of the debris bin <NUM>. Thus, the flap <NUM> cannot inadvertently contact objects outside of the debris bin <NUM>, such as the floor surface <NUM> about which the mobile robot <NUM> moves. In some cases, the flap <NUM>, at a full extension toward the exterior surface <NUM> when the flap <NUM> is in the open position (<FIG>), the flap <NUM> is above the exterior surface <NUM> by a distance between <NUM> and <NUM>. In some implementations, the flap <NUM> may extend past the exterior surface <NUM>. In such cases, to prevent the flap <NUM> from contacting the floor surface (e.g., the surface <NUM> of <FIG>), the flap <NUM> can extend a distance less than the clearance distance <NUM>.

The biasing mechanism <NUM> (e.g., which can include the torsion spring <NUM>, the leaf spring <NUM>, or the relaxing spring <NUM>) can have a nonlinear response to the air pressure at the exhaust port <NUM>. For example, as the flap <NUM> moves from the closed position to the open position, the torque generated by the biasing mechanism <NUM> can decrease because a lever arm about the axis <NUM> for the biasing force of the biasing mechanism <NUM> decreases. Thus, the biasing mechanism <NUM> can require a first air pressure to move initially from the closed position (<FIG>) to the open position (<FIG>) that is higher than a second air pressure to maintain the door in the open position (<FIG>). The first air pressure can be <NUM>% to <NUM>% greater than the second air pressure, depending on conditions in the environment and the composition of the debris.

The door unit <NUM> can be positioned to increase the speed at which debris <NUM> can be evacuated from the debris bin <NUM>. Referring <FIG>, which shows the flap <NUM> in the closed position (e.g., as shown in <FIG>), the door unit <NUM> is located on a half <NUM> of a full length <NUM> of the debris bin <NUM>. The door unit <NUM> is located opposite to the suctioning mechanism <NUM> that occupies a half <NUM> of the full length <NUM>. The door unit <NUM> is located adjacent a corner <NUM> of the debris bin <NUM> such that the door unit <NUM> is within a distance of <NUM>% to <NUM>% of the full length <NUM> of the debris bin <NUM> to the corner <NUM>. The door unit <NUM> can be partially located within a rearward portion <NUM> of the debris bin <NUM>. The flap <NUM> faces outwardly towards the debris bin <NUM> from the corner <NUM> such that debris <NUM> from a large portion of the debris bin <NUM> is directed toward the path <NUM> provided by the flap <NUM> in the open position (<FIG>). As a result, when the flap <NUM> is in the open position (<FIG>) and the evacuation station has initiated the evacuation operation, the negative air pressure can cause debris <NUM> from difficult-to-reach locations throughout the debris bin <NUM>-including, for example, corners and areas in the rearward portion <NUM>-to flow into the path <NUM> to be evacuated into the evacuation station.

In an example, the full length <NUM> of the debris bin <NUM> is between <NUM> and <NUM> centimeters. The debris bin can have a width <NUM> between <NUM> and <NUM> centimeters. The door unit <NUM> is located between <NUM> to <NUM> centimeters from the corner <NUM> (e.g., a horizontal distance between <NUM> and <NUM> centimeters, a vertical distance between <NUM> and <NUM> centimeters). The door unit <NUM> can have a diameter between <NUM> centimeters and <NUM> centimeters.

As shown in <FIG>, <FIG>, and <FIG>, the flap <NUM> can be made of a solid plastic or other rigid material and can be concavely curved relative to, the support structure <NUM>. Thus, air pressure within the debris bin <NUM> on the flap <NUM> during the evacuation operation can result in greater forces on the flap <NUM> to cause the flap <NUM> to more easily move from the open position (<FIG>) to the closed position (<FIG>).

A stretchable material <NUM> can cover part of the flap <NUM> such that debris <NUM> entering through the path <NUM> when the flap <NUM> is open (<FIG>) does become lodged between the flap <NUM> and the support structure <NUM>. The stretchable material <NUM> can be formed of a resilient material, such as an elastomer. In some implementations, the stretchable material <NUM> can be formed of ethylene propylene diene monomer (EPDM) rubber, silicone rubber, polyether block amides, Chloropene rubber, Butyl rubber, among other elastomeric materials. As shown in <FIG>, the stretchable material <NUM> can cover an intersection <NUM> (shown in <FIG> of the flap <NUM> and the support structure <NUM>. Debris <NUM> and other foreign material along the intersection <NUM> can prevent the flap <NUM> from closing and forming a seal with the support structure <NUM>. Thus, the stretchable material <NUM> prevents debris <NUM> from gathering at the intersection <NUM> so that the debris <NUM> does not interfere with proper functionality of the flap <NUM> of the door unit <NUM>. In some implementations, the hinge and stretchable material could be replaced with a flexible coupler (e.g., as described with respect to <FIG>) made of similar stretchable materials to perform the same function. In such implementations, the flap <NUM> is attached to the support structure <NUM> by the flexible coupler.

An adhesive can be used to adhere the stretchable material <NUM> to the flap <NUM> and to the support structure <NUM>. The stretchable material <NUM> can be adhered to the flap <NUM> along a fixed portion <NUM> and can be adhered to the support structure <NUM> along a fixed portion <NUM>. The adhesive can be absent at a location <NUM> of or above the hinge (e.g., the hinge <NUM>) about which the flap <NUM>. The adhesive can further be absent at the intersection <NUM> of the flap <NUM> and the support structure <NUM>. Thus, the stretchable material <NUM> can flex and deform along the location <NUM> while the fixed portions <NUM>, <NUM> of the stretchable material <NUM> remain fixed to the flap <NUM> and the support structure <NUM>, respectively, and do not flex. The absence of adhesive along the location <NUM> provides a flexible portion for the stretchable material <NUM> so that the stretchable material <NUM> does not break or fracture due to excessive stress caused by the movement of the flap <NUM> from the closed position (<FIG>) to the open position (<FIG>).

During the cleaning operation, the flap <NUM> biased into the closed position (<FIG>) due to the biasing mechanism <NUM> prevents the debris <NUM> from exiting the debris bin <NUM> through the exhaust port <NUM>. During an evacuation operation, the mobile robot <NUM> docks at the evacuation station so that the evacuation station can generate negative air pressure to evacuate the debris <NUM>. The debris <NUM> can flow through the exhaust port <NUM> with air flow generated during the evacuation operation. The flap <NUM>, forced into the open position (<FIG>) due to the negative air pressure generated during the evacuation operation, provides the path <NUM> so that the debris <NUM> can travel along a flow path (e.g., flow path <NUM>) to a bag (e.g., bag <NUM>) of the evacuation station. As the debris flow through the exhaust port <NUM>, the stretchable material <NUM> further prevents the debris <NUM> from gathering around the biasing mechanism <NUM> and at the intersection <NUM>. Thus, after the evacuation operation, the biasing mechanism <NUM> can easily bias the flap <NUM> into the closed position (<FIG>), and the mobile robot <NUM> can continue the cleaning operation and continue ingesting debris <NUM> and storing debris <NUM> in the debris bin <NUM>.

The robots described herein can be controlled, at least in part, using one or more computer program products, e.g., one or more computer programs tangibly embodied in one or more information carriers, such as one or more non-transitory machine-readable media, for execution by, or to control the operation of, one or more data processing apparatus, e.g., a programmable processor, a computer, multiple computers, and/or programmable logic components.

Operations associated with controlling the robots described herein can be performed by one or more programmable processors executing one or more computer programs to perform the functions described herein. Control over all or part of the robots and evacuation stations described herein can be implemented using special purpose logic circuitry, e.g., an FPGA (field programmable gate array) and/or an ASIC (application-specific integrated circuit).

Generally, a processor will receive instructions and data from a read-only storage area or a random access storage area or both. Elements of a computer include one or more processors for executing instructions and one or more storage area devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from, or transfer data to, or both, one or more machine-readable storage media, such as mass PCBs for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Machine-readable storage media suitable for embodying computer program instructions and data include all forms of non-volatile storage area, including by way of example, semiconductor storage area devices, e.g., EPROM, EEPROM, and flash storage area devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

Claim 1:
An evacuation station (<NUM>; <NUM>) configured to hold a bag comprising:
a control system (<NUM>) comprising one or more processing devices programmed to control evacuation of a debris bin (<NUM>; <NUM>) of a mobile robot (<NUM>; <NUM>);
a base (<NUM>) to receive the mobile robot, the base comprising an intake port (<NUM>) to align to an exhaust port (<NUM>) of the debris bin;
a canister (<NUM>) to hold a bag (<NUM>) to store debris from the debris bin;
one or more conduits (230a; 230b; 230c) extending from the intake port to the bag, through which debris is transported between the intake port and the bag,
wherein the cannister further comprises:
a top (<NUM>) movable between an open position and a closed position;
a motor (<NUM>) that is responsive to commands from the control system to remove air from the canister and thereby generate negative air pressure in the canister to evacuate the debris bin by suctioning the debris from the debris bin,
characterized in that:
the cannister further comprises slots that align the bag with a bag interface end (<NUM>) of the one or more conduits,
and that
the motor is positioned below the cannister.