TECHNICAL FIELD

This specification relates generally to evacuating debris collected by a mobile robot.

BACKGROUND

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.

SUMMARY

In some examples, a mobile robot includes a body configured to traverse a surface and to receive debris from the surface, and a debris bin within the body. The debris bin includes a chamber to hold the debris received by the mobile robot, an exhaust port through which the debris exits the debris bin; and a door unit over the exhaust port. The door unit includes a flap configured to move, in response to air pressure at the exhaust port, between a closed position to cover the exhaust port and an open position to open a path between the chamber and the exhaust port. The door unit, including the flap in the open position and in the closed position, is within an exterior surface of the mobile robot.

In some examples, the door unit can include a semi-spherical support structure within the debris bin. The flap can be mounted on, and concavely curved relative to, the semi-spherical support structure.

The exhaust port and the door unit can be adjacent to a corner of the debris bin and can be positioned so that the flap faces outwardly towards the debris bin relative to the corner.

The flap can be connected to the semi-spherical support structure by one or more hinges. The door unit can further include a stretchable material adhered, by an adhesive, to both the flap and the semi-spherical support structure. The stretchable material can cover the one or more hinges and an intersection of the flap and the semi-spherical support structure. The adhesive can be absent at a location of the one or more hinges and at the intersection of the flap and the semi-spherical support structure.

The flap can be connected to the semi-spherical support structure by a biasing mechanism. In some examples, the biasing mechanism can include a torsion spring. The torsion spring can be connected to both the flap and the semi-spherical support structure. The torsion spring can have a nonlinear response to the air pressure at the exhaust port. The torsion spring can require a first air pressure to move and thereby place the flap in an open position and a second air pressure to maintain the flap in the open position. The first air pressure can be greater than the second air pressure.

In some examples, the biasing mechanism can include a relaxing spring that can require a first air pressure to move and thereby place the flap in an open position and a second air pressure to maintain the flap in the open position. The first air pressure can be greater than the second air pressure.

In some examples, the mobile robot can be a vacuum cleaner including a suction mechanism. The surface can be a floor. The mobile robot can further include a controller to control operation of the mobile robot to traverse the floor. The controller can control the suction mechanism for suctioning debris from the floor into the debris bin during traversal of the floor.

In some examples, 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 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, and a pressure sensor to monitor the air pressure. The control system is programmed to control an amount of time to evacuate the debris bin based on the air pressure monitored by the pressure sensor.

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.

In some examples, the canister can include 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.

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

