Patent Description:
<CIT> and <CIT> disclose cleaning pads for cleaning an environment.

Certain cleaning robots can include a cleaning pad. The cleaning pad can be mounted on an underside of the cleaning robot and can collect debris during a cleaning mission of the cleaning robot. In certain situations, dust bunnies can accumulate in front of the cleaning pad. Dust bunnies most commonly occur in areas not frequently cleaned (e.g., underneath furniture) and can include collections of hair and/or lint. The accumulated dust bunnies can interfere with the normal operation of cleaning robot sensors, such as by occluding the cleaning robot sensors. The inventors have recognized, among other things, that it may be possible to provide a cleaning pad that can mitigate the accumulation of dust bunnies in front of the cleaning pad during a cleaning mission of the cleaning robot, such as to reduce interference with the cleaning robot sensors.

According to the invention, a cleaning pad includes a mounting surface disposed on a top side of the cleaning pad. The mounting surface is configured to provide a mechanical connection to an autonomous cleaning robot. The cleaning pad includes a first outer layer disposed on a bottom side of the cleaning pad, the first outer layer having a first coefficient of friction; and a second outer layer disposed on the bottom side of the cleaning pad, the second outer layer having a second coefficient of friction less than the first coefficient of friction. The second outer layer is disposed forward of at least a portion of the first outer layer at a forward portion of the cleaning pad.

Embodiments can include one or more of the following features.

A surface area of the first outer layer is larger than a surface area of the second outer layer. A ratio of the surface area of the first outer layer to the surface area of the second outer layer is between <NUM>:<NUM> and <NUM>: <NUM>.

A forward portion of the cleaning pad is angled relative to a rear portion of the cleaning pad. An angle between the forward portion of the pad and the rear portion of the pad is between <NUM>° and <NUM>°.

The second outer layer includes a layer of material wrapped around a forward edge of the cleaning pad.

The cleaning pad includes a core, in which the mounting surface is disposed on a top surface of the core and the first and second outer layers are disposed on a bottom surface of the core. The first outer layer includes a layer of material wrapped around the core. The first outer layer is disposed directly on the bottom surface of the core, and the second outer layer is disposed on a forward portion of the first outer layer. The first outer layer is disposed directly on a rear portion of the bottom surface of the core, and the second layer is disposed directly on a forward portion of the bottom surface of the core.

The second outer layer includes a polymer, such as a polymer layer having a release coating.

The second outer layer includes a thin film coating.

The second outer layer includes a folded layer of material. The folded layer of material of the second outer layer defines a rear-facing opening.

The second outer layer spans an entire width of the cleaning pad.

A thickness of a forward segment of the cleaning pad is greater than a thickness of a rear segment of the cleaning pad.

A depression is defined in a bottom surface of the cleaning pad to a rear of the second outer layer.

The second coefficient of friction is less than half of the first coefficient of friction.

In an aspect, an autonomous cleaning robot includes a robot body including a forward portion and a rear portion; a drive system to maneuver the robot body across a floor surface; a cleaning assembly affixed to the forward portion of the robot body, the cleaning assembly including a pad holder; and a cleaning pad affixed to the pad holder of the cleaning assembly by a mounting surface of the cleaning pad. The mounting surface of the cleaning pad is disposed on a top side of the cleaning pad. The cleaning pad includes a first outer layer disposed on a bottom side of the cleaning pad, the first outer layer having a first coefficient of friction; and a second outer layer disposed on the bottom side of the cleaning pad, the second outer layer having a second coefficient of friction less than the first coefficient of friction. The second outer layer is disposed forward of at least a portion of the first outer layer at a forward portion of the cleaning pad.

A leading edge of the cleaning pad is aligned with a leading edge of the robot body.

A surface area of the first outer layer of the cleaning pad is larger than a surface area of the second outer layer.

A forward portion of the cleaning pad is angled relative to a rear portion of the cleaning pad.

The cleaning pad includes a core, in which the mounting surface is disposed on a top surface of the core and the first and second outer layers are disposed on a bottom surface of the core. The first outer layer is disposed directly on the bottom surface of the core, and the second outer layer is disposed on a forward portion of the first outer layer.

Described herein is a cleaning pad for an autonomous cleaning robot that includes a low-friction layer at a forward portion of the cleaning pad and a fibrous layer at a rear portion of the cleaning pad. The presence of the low-friction layer helps to reduce the accumulation of debris, such as dust or pet hair, at or near a leading edge of the cleaning pad. The leading edge of the cleaning pad is positioned near cliff sensors of the autonomous cleaning robot, which detect flooring height changes, e.g., to prevent the autonomous cleaning robot from falling down a drop, such as a stair. By reducing the accumulation of debris in the vicinity of the cliff sensors, the functioning of the cliff sensors can be reliable and robust to a range of floor cleanliness conditions, and the structural integrity of the autonomous cleaning robot can be protected against damage from falls.

Referring to <FIG>, a cleaning pad <NUM> is attached to an example autonomous cleaning robot <NUM>. A drive system maneuvers the autonomous cleaning robot <NUM> is across a floor surface <NUM>. Wheels <NUM> support a rear portion <NUM> of the autonomous cleaning robot <NUM>, and the cleaning pad <NUM> supports a forward portion <NUM> of the autonomous cleaning robot <NUM>. As the autonomous cleaning robot <NUM> navigates the floor surface <NUM>, the cleaning pad <NUM> contacts the floor surface <NUM>, providing cleaning functionality, such as wet mopping or dry cleaning functionality. The cleaning pad <NUM> is reversibly attached to a pad holder <NUM> of the autonomous cleaning robot <NUM>, e.g., such that the cleaning pad <NUM> can be replaced after the autonomous cleaning robot <NUM> completes execution of a cleaning mission or when the cleaning pad <NUM> becomes soiled. The cleaning pad <NUM> can be a disposable cleaning pad or a reusable cleaning pad.

<FIG> shows a bottom view of the autonomous cleaning robot <NUM>. The cleaning pad <NUM> is disposed toward the forward portion <NUM> of the autonomous cleaning robot <NUM> to provide cleaning functionality as the autonomous cleaning robot navigates the floor surface.

The autonomous cleaning robot <NUM> includes forward cliff sensors 200a, 200b (collectively cliff sensors <NUM>) disposed in the forward corners of the autonomous cleaning robot <NUM>. The cliff sensors <NUM> can be mechanical drop sensors or light based proximity sensors, such as an IR (infrared) pair, a dual emitter-single receiver, or dual receiver-single emitter IR light-based proximity sensor aimed downward at the floor surface. The cliff sensors <NUM> span between sidewalls of the autonomous cleaning robot <NUM> and cover the corners closely to detect flooring height changes beyond a threshold accommodated by reversible robot wheel drop prior to traversal of the respective floor portions by the autonomous cleaning robot <NUM>. For example, the placement of the cliff sensors <NUM> proximate the corners of the autonomous cleaning robot <NUM> helps to ensure that the cliff sensors <NUM> trigger when the autonomous cleaning robot <NUM> overhangs a flooring drop, preventing the robot wheels <NUM> from advancing over the drop edge.

The example autonomous cleaning robot <NUM> includes one forward cliff sensor 200a, 200b in each forward corner. In some examples, an autonomous cleaning robot can include only a single forward cliff sensor, or can include two or more cliff sensors. In some examples, an autonomous cleaning robot can include one or more rear cliff sensors disposed in the rear portion <NUM> of the autonomous cleaning robot <NUM>, e.g., in one or more of the rear corners.

As the autonomous cleaning robot <NUM> navigates the floor surface to execute a dry cleaning mission, a forward portion <NUM> of the cleaning pad <NUM> crosses the floor surface before a rear portion <NUM> of the cleaning pad <NUM>, when the autonomous cleaning robot <NUM> is moving in a forward direction. For some cleaning pads, during a cleaning mission, debris from the floor surface can build up on the forward portion of the cleaning pad that is attached to the autonomous cleaning robot. For instance, debris, such as dust bunnies or pet hair, can become ensnared in a leading edge of the cleaning pad. In some cases, the debris buildup can be significant enough to occlude one or more of the forward cliff sensors <NUM>, which can hinder the ability of the cliff sensors <NUM> to detect flooring height changes.

To help prevent buildup of debris at the forward portion <NUM> of the cleaning pad <NUM>, a low-friction layer <NUM> is disposed at the forward portion <NUM> of the cleaning pad <NUM>. A fibrous layer <NUM> is disposed at a rear portion <NUM> of the cleaning pad <NUM>. The coefficient of friction between the low-friction layer <NUM> and debris is less than a coefficient of friction between the fibrous layer <NUM> and debris. For simplicity, the coefficient of friction between the low-friction layer <NUM> and debris is sometimes referred to as just the coefficient of friction of the low-friction layer <NUM>, and the coefficient of friction between the fibrous layer <NUM> and debris is sometimes referred to as just the coefficient of friction of the fibrous layer <NUM>. The low-friction layer <NUM> and the fibrous layer <NUM> are substantially coplanar, e.g., at least portions of both the low-friction layer <NUM> and the fibrous layer <NUM> are disposed on a bottom surface <NUM> of the cleaning pad <NUM>.

For some debris, the coefficient of friction between the debris and the floor surface is higher than the coefficient of friction between the debris and the low-friction layer <NUM>. Moreover, the coefficient of friction between the debris and the floor surface can be lower than the coefficient of friction between the debris and the fibrous layer <NUM>. In such instances, the debris will slip past the forward portion <NUM> of the cleaning pad <NUM>, accumulating at the rear portion <NUM> of the cleaning pad <NUM>, where it does not block the functioning of the cliff sensors. As the low-friction layer <NUM> of the cleaning pad <NUM> moves over the debris, the debris is compressed by the pressure applied on the floor surface by the cleaning pad <NUM>. When the fibrous layer <NUM> passes over the debris, the debris accumulates at the fibrous layer <NUM>, e.g., the debris is ensnared in fibers of the fibrous layer, keeping the cliff sensors <NUM> clear. In some examples, the forward portion <NUM> of the cleaning pad <NUM> is thicker than the rear portion <NUM> of the cleaning pad <NUM> to facilitate compression of debris as the cleaning pad <NUM> passes over the debris.

Referring to <FIG>, for some debris <NUM>, the coefficient of friction between the debris <NUM> and the floor surface <NUM> is relatively low, or the debris <NUM> is too large to slip between the cleaning pad <NUM> and the floor surface <NUM>. Such debris <NUM> can build up at the forward portion <NUM> of the cleaning pad <NUM>, as shown in <FIG>. However, because the forward portion <NUM> of the cleaning pad <NUM>, e.g., the leading edge of the cleaning pad <NUM>, is formed of a slick, low-friction material, the accumulated debris is not ensnared in the cleaning pad. When the autonomous cleaning robot <NUM> navigates to the vicinity of a cliff <NUM>, the accumulated debris <NUM> can drop away from the autonomous cleaning robot <NUM>, as shown in <FIG>, freeing the cliff sensors <NUM> to detect the cliff <NUM> before the autonomous cleaning robot <NUM> navigates past the edge of the cliff <NUM>.

<FIG> are bottom and top views, respectively, of the cleaning pad <NUM>. The low-friction layer <NUM> is disposed at the forward portion <NUM> of the cleaning pad <NUM> and the fibrous layer <NUM> is disposed at the rear portion <NUM> of the cleaning pad <NUM>. In some examples, the low-friction layer <NUM> and the fibrous layer <NUM> are adjacent to one another. In some examples, the fibrous layer <NUM> extends toward the forward portion <NUM> of the cleaning pad <NUM> such that the low-friction layer <NUM> is disposed on a forward portion of the fibrous layer <NUM>. For instance, the fibrous layer <NUM> can cover the entire bottom surface <NUM> of the cleaning pad <NUM>, with the low-friction layer <NUM> being disposed on the forward portion of the bottom surface.

The coefficient of friction between the low-friction layer <NUM> and debris on the floor surface is less than the coefficient of friction between the fibrous layer <NUM> and the debris. For instance, the coefficient of friction between the low-friction layer <NUM> and debris can be between about <NUM>% and about <NUM>% of the coefficient of friction between the fibrous layer <NUM> and the debris, e.g., between about <NUM>% and about <NUM>%, e.g., between about <NUM>% and about <NUM>%. For instance, the coefficient of friction between the fibrous layer <NUM> and debris can be between about <NUM> and about <NUM>, and the coefficient of friction between the low-friction layer <NUM> and debris can be between about <NUM> and about <NUM>.

The fibrous layer <NUM> can be a fibrous, non-woven material. The low-friction layer <NUM> can be a woven material, such as a satin or satin-like material. The low-friction layer <NUM> can include a polymer, such as polyethylene terephthalate (PET) or polytetrafluoroethylene (PTFE). In some examples, the low-friction layer <NUM> can be a polymer layer having a release coating, e.g., a silicone release coating.

In the example cleaning pad <NUM>, the fibrous layer <NUM> and the low-friction layer <NUM> both span a width w of the cleaning pad <NUM>. A surface area of the fibrous layer <NUM> (e.g., the surface area of the fibrous layer <NUM> on the bottom surface <NUM> of the cleaning pad <NUM>) is equal to or greater than a surface area of the low-friction layer <NUM> (e.g., the surface area of the low-friction layer <NUM> on the bottom surface <NUM> of the cleaning pad <NUM>). For instance, a ratio of the surface area of the fibrous layer <NUM> to the surface area of the low-friction layer <NUM> can be between about <NUM>:<NUM> and about <NUM>:<NUM>, e.g., between about <NUM>:<NUM> and about <NUM>:<NUM>, e.g., about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, or about <NUM>:<NUM>. The ratio of the surface area of the fibrous layer <NUM> to the surface area of the low-friction layer <NUM> can be such that the cleaning pad retains a substantial amount of its cleaning capabilities, which are generally provided by the fibrous layer <NUM>, while achieving the ability to keep the cliff sensors free of debris, as provided by the low-friction layer <NUM>.

In the cleaning pad <NUM>, the fibrous layer <NUM> is wrapped around the cleaning pad <NUM> such that the fibrous layer <NUM> is also present on a top surface <NUM> of the cleaning pad <NUM> (<FIG>). The low-friction layer <NUM> is wrapped around a leading edge <NUM> of the cleaning pad <NUM> such that a portion of the low-friction layer <NUM> is disposed on a top surface <NUM> of the cleaning pad <NUM> (<FIG>). In some examples, the low-friction layer <NUM> is disposed only on the bottom surface <NUM> of the cleaning pad <NUM> and does not wrap around the leading edge <NUM> or onto the top surface <NUM>. In some examples, the fibrous layer <NUM> is disposed only on the bottom surface <NUM> of the cleaning pad <NUM>.

A mounting surface <NUM> is disposed on the top surface <NUM> of the cleaning pad <NUM> for mechanical connection to the autonomous cleaning robot. For instance, the mounting surface <NUM> can be shaped to be received by the pad holder <NUM> (<FIG>) of the autonomous cleaning robot <NUM>. The mounting surface <NUM> can be, e.g., cardstock, plastic, or another material appropriate for securing the cleaning pad <NUM> to the pad holder of the autonomous cleaning robot <NUM>. When the cleaning pad <NUM> is mounted on the autonomous cleaning robot, the bottom surface <NUM> of the cleaning pad <NUM>, including the fibrous and low-friction layers <NUM>, <NUM>, faces the floor surface to be cleaned.

Referring to <FIG>, in some examples, a cleaning pad <NUM> for use with the autonomous cleaning robot <NUM> is composed of multiple segments 520a-520e (collectively referred to as segments <NUM>). The cleaning pad <NUM> is composed of five segments, but in some examples cleaning pads can be composed of more or fewer segments. The segments <NUM> are defined by transition regions 522a-522d (collectively referred to as transition regions <NUM>), each extending across the width of the cleaning pad <NUM>. In each transition region <NUM>, the elements of the cleaning pad <NUM> (e.g., one or more of core layers, discussed below; a low-friction layer, and a fibrous layer) are secured together through the thickness of the cleaning pad <NUM>, such that the transition regions <NUM> to have a thickness that is less than the thickness of the segments <NUM> of the cleaning pad <NUM>.

A forward segment 520a of the cleaning pad <NUM> includes a low-friction layer <NUM>, and rear segments 520b-520e of the cleaning pad <NUM> include a fibrous layer <NUM>. The low friction layer <NUM> has a lower coefficient of friction than the fibrous layer <NUM>, e.g., as described above for the layers <NUM>, <NUM> of <FIG>. In some examples, multiple segments include the low-friction layer <NUM>.

In some examples, the forward segment 520a of the cleaning pad <NUM> is thicker than one or more of the rear segments 520b-520e, e.g., to facilitate compression of debris by the cleaning pad <NUM>. In some examples, one or more segments, e.g., the second segment 520b, of the cleaning pad <NUM> are thinner than the forward segment 520a, to provide a volume within which debris can accumulate.

In the cleaning pad <NUM>, the segments <NUM> have equal length along the direction of travel x of the cleaning pad. In some cleaning pads, one or more of the segments <NUM> can be longer or shorter than one or more of the other segments.

The segments <NUM> of the cleaning pad <NUM> can be formed by mechanical processing of a cleaning pad without segments, e.g., by mechanical embossing, ultrasonic welding, or other types of mechanical processing. Additional details about segmented cleaning pads can be found in <CIT>, the contents of which are incorporated here by reference in their entirety.

<FIG> shows a cross section of a forward portion of an example cleaning pad <NUM>, e.g., for use with the autonomous cleaning robot <NUM> of <FIG>. For instance, the cross sectional profile shown in <FIG> can be a cross sectional profile of the cleaning pad <NUM> of <FIG>. The cleaning pad <NUM> includes a core <NUM>. A fibrous layer <NUM> is disposed directly on and wrapped around the core <NUM>. A low-friction layer <NUM> is disposed on a forward portion of the fibrous layer <NUM> and wrapped around a leading edge <NUM> of the cleaning pad <NUM>. For instance, the low-friction layer <NUM> can be a tape, a spray coating, a thin film, or another suitable form of material that is applied to the forward portion of the fibrous layer <NUM>. In this configuration, both the fibrous layer <NUM> and the low-friction layer <NUM> are disposed on a bottom surface <NUM> of the cleaning pad <NUM>. The low friction layer <NUM> has a lower coefficient of friction than the fibrous layer <NUM>, e.g., as described above for the layers <NUM>, <NUM> of <FIG>. In some examples, both the fibrous layer <NUM> and the low-friction layer <NUM> are disposed directly on the core <NUM>, with the fibrous layer <NUM> being disposed directly on a rear portion of the core <NUM> and the low-friction layer <NUM> being disposed directly on a forward portion of the core <NUM>.

In the cleaning pad <NUM>, the fibrous layer <NUM> is wrapped around the entire surface of the core <NUM>, forming an overlap region <NUM> on the top surface of the cleaning pad <NUM> in which the fibrous layer <NUM> overlaps both itself and the low-friction layer <NUM>. The presence of the overlap region <NUM> lends mechanical stability to the structure of the cleaning pad <NUM> and prevents the low-friction layer <NUM> from peeling loose from the surface of the cleaning pad <NUM>.

The core <NUM> of the cleaning pad <NUM> includes multiple sub-layers, including a top structural layer 632a, a bottom structural layer 632b, and a compressible layer <NUM>. In some examples, the core <NUM> can include additional sub-layers. In some examples, the core <NUM> can be a single layer of material.

<FIG> shows a cross section of a forward portion of an example cleaning pad <NUM>, e.g., for use with the autonomous cleaning robot <NUM> of <FIG>. The cleaning pad <NUM> is composed of multiple segments 720a-720c (collectively referred to as segments <NUM>). For instance, the cross sectional profile shown in <FIG> can be a cross sectional profile of the cleaning pad <NUM> of <FIG>.

The cleaning pad <NUM> includes a core <NUM> that includes multiple sub-layers, including a top structural layer 732a, a bottom structural layer 732b, and a compressible layer <NUM>. The top structural layer 732a extends further forward than the bottom structural layer 732b.

A fibrous layer <NUM> is disposed directly on and wrapped around the core <NUM>. A low-friction layer <NUM> is disposed on the fibrous layer <NUM> at a forward segment 720a of the cleaning pad <NUM>, and wrapped around a leading edge <NUM> of the cleaning pad <NUM>. In some examples, both the fibrous layer <NUM> and the low-friction layer <NUM> are disposed directly on the core <NUM>. The low friction layer <NUM> has a lower coefficient of friction than the fibrous layer <NUM>, e.g., as described above for the layers <NUM>, <NUM> of <FIG>.

The process of forming the segments <NUM> in the cleaning pad <NUM> causes a tension force to be applied to the fibrous layer <NUM> and low-friction layer <NUM> on the bottom surface of the cleaning pad <NUM> because of the difference in length between the top and bottom structural layers 732a, 732b of the core <NUM>. The tension on the layers <NUM>, <NUM> pulls the longer top structural layer 732a downwards, causing a forward portion <NUM> of the cleaning pad <NUM> to be angled downwards relative to a rear portion <NUM> of the cleaning pad <NUM>. For instance, the angle θ of the forward portion <NUM> of the cleaning pad <NUM> relative to the plane of the cleaning pad <NUM> can be between about <NUM>° and about <NUM>°, e.g., about <NUM>°. Having the forward portion <NUM> of the cleaning pad <NUM> angled downwards can enable the forward portion <NUM> of the cleaning pad <NUM> to act as a plow, pushing debris forward as the autonomous cleaning robot navigates over the debris.

<FIG> shows a forward portion of an example cleaning pad <NUM>, e.g., for use with the autonomous cleaning robot <NUM> of <FIG>. The cleaning pad <NUM> is composed of multiple segments 820a-820c (collectively referred to as segments <NUM>). For instance, the cross sectional profile shown in <FIG> can be a cross sectional profile of the cleaning pad <NUM> of <FIG>.

The cleaning pad <NUM> includes a core <NUM> that has multiple sub-layers, including a top structural layer 832a, a bottom structural layer 832b, and a compressible layer <NUM>. The bottom structural layer 832b extends further forward than the top structural layer 832a.

A fibrous layer <NUM> is disposed directly on and wrapped around the core <NUM>. A low-friction layer <NUM> is disposed on the fibrous layer <NUM> at a forward segment 820a of the cleaning pad <NUM>, and wrapped around a leading edge <NUM> of the cleaning pad <NUM>. The low friction layer <NUM> has a lower coefficient of friction than the fibrous layer <NUM>, e.g., as described above for the layers <NUM>, <NUM> of <FIG>.

The process of forming the segments <NUM> in the cleaning pad <NUM> causes a tension force to be applied to the fibrous layer <NUM> and low-friction layer <NUM> on the top surface of the cleaning pad <NUM> because of the difference in length between the top and bottom structural layers 832a, 832b of the core <NUM>. the tension on the layers <NUM>, <NUM> pulls the longer bottom structural layer 832b upwards, causing a forward portion <NUM> of the cleaning pad <NUM> to be angled upwards relative to a rear portion <NUM> of the cleaning pad <NUM>. For instance, the angle θ of the forward portion <NUM> of the cleaning pad <NUM> relative to the plane of the cleaning pad <NUM> can be between about <NUM>° and about <NUM>°, e.g., about <NUM>°. Having the forward portion <NUM> of the cleaning pad <NUM> angled upwards can enable the forward portion <NUM> to act as a wedge, driving debris under the cleaning pad <NUM>, where the debris is compressed and ensnared by the fibrous layer <NUM>.

<FIG> shows a bottom view of an example cleaning pad <NUM>, e.g., for use with the autonomous cleaning robot <NUM> of <FIG>. The cleaning pad <NUM> has a fibrous layer <NUM> disposed across the entire extent of a bottom surface of the cleaning pad. For instance, the fibrous layer <NUM> can be wrapped around the cleaning pad. A discontinuous low-friction layer disposed on the fibrous layer <NUM> at a forward portion <NUM> of the cleaning pad <NUM> includes first and second low-friction regions 904a, 904b (referred to collectively as a low-friction layer <NUM>), such that the low-friction layer <NUM> does not span the entire width w of the cleaning pad <NUM>. In this configuration, a portion of a leading edge <NUM> of the cleaning pad <NUM> includes material of the low-friction layer <NUM>, and a portion of the leading edge <NUM> includes material of the fibrous layer <NUM>. The low-friction layer <NUM> has a coefficient of friction that is less than the coefficient of friction of the fibrous layer <NUM>, as discussed above. The first and second low-friction regions <NUM> are positioned such that when the cleaning pad <NUM> is mounted on an autonomous cleaning robot, the first and second low-friction regions <NUM> are positioned generally near the forward cliff sensors of the autonomous cleaning robot.

The cleaning pad <NUM> of <FIG> has segments 920a-920e, and the first and second low-friction regions <NUM> occupy portions of a forward segment 920a. The remainder of the forward segment 920a is formed by the fibrous layer <NUM>. In some examples, a cleaning pad without segments can include a discontinuous low-friction layer that does not span the entire width of the cleaning pad.

In the cleaning pad <NUM>, the ratio of the surface area of the fibrous layer <NUM> to the surface area of the low-friction layer <NUM> can be higher than for cleaning pads in which the low-friction layer <NUM> extends across the entire width of the cleaning pad. For instance, the ratio of the surface area of the fibrous layer <NUM> to the surface area of the low-friction layer <NUM> can be between about <NUM>:<NUM> and about <NUM>:<NUM>, enabling the cleaning pad <NUM> to retain more of the cleaning capabilities provided by the fibrous layer <NUM>, while achieving the ability to keep the cliff sensors free of debris, as provided by the low-friction regions 904a, 904b aligned with the cliff sensors.

<FIG> shows a bottom view of an example cleaning pad <NUM>, e.g., for use with the autonomous cleaning robot <NUM> of <FIG>. A fibrous layer <NUM> is disposed on a rear portion <NUM> of a bottom surface of the cleaning pad <NUM>, and a low-friction layer <NUM> is disposed on a forward portion <NUM> of the bottom surface of the cleaning pad <NUM>. The low-friction layer <NUM> has a lower coefficient of friction than the fibrous layer <NUM>, e.g., as described above for the layers <NUM>, <NUM> of <FIG>. Depressions <NUM> are formed in the bottom surface of the cleaning pad <NUM> to the rear of the low-friction layer <NUM>. When an autonomous cleaning robot having the cleaning pad <NUM> attached thereto navigates over debris, the debris slips past the low-friction forward portion <NUM> of the cleaning pad <NUM> and accumulates in the depressions <NUM>, keeping the bottom surface <NUM> of the cleaning pad <NUM> free to clean the floor surface.

The cleaning pad <NUM> of <FIG> has segments 970a-970e, with the depressions <NUM> being formed in a second segment 970b. In some examples, a cleaning pad without segments can have depressions formed in its bottom surface.

<FIG> show cross sectional views of an example cleaning pad <NUM>, e.g., for use with the autonomous cleaning robot <NUM> of <FIG>. <FIG> shows the configuration of the cleaning pad <NUM> when attached to an autonomous cleaning robot that is moving forward, e.g., such that a forward portion <NUM> of the cleaning pad <NUM> contacts the floor surface before a rear portion <NUM> of the cleaning pad <NUM>. <FIG> shows the configuration of the cleaning pad when the autonomous cleaning robot is moving in reverse, e.g., such that the rear portion <NUM> of the cleaning pad <NUM> contacts the floor surface before the forward portion <NUM>.

The cleaning pad <NUM> includes a low-friction layer <NUM> disposed on a forward portion <NUM> of a bottom surface <NUM> of the cleaning pad <NUM>, and a fibrous layer <NUM> disposed on a rear portion <NUM> of the bottom surface <NUM>. The low-friction layer <NUM> has a lower coefficient of friction than the fibrous layer <NUM>, e.g., as described above for the layer <NUM>, <NUM> of <FIG>. The cleaning pad <NUM> also includes a folded element, such as a flap <NUM>, with a first edge <NUM> of the flap <NUM> being affixed to the low-friction layer <NUM> and a second edge <NUM> of the flap <NUM> being free. A first side <NUM> of the flap <NUM> is formed of the material of the low-friction layer and a second side <NUM> of the flap is formed of the material of the fibrous layer.

When the autonomous cleaning robot moves forward, the flap <NUM> is in the configuration of <FIG>, with the flap <NUM> being oriented toward the rear portion <NUM> of the cleaning pad <NUM> and a pocket <NUM> being defined between the flap <NUM> and the bottom surface <NUM> of the cleaning pad <NUM>. The low-friction material on the first side <NUM> of the flap <NUM> is exposed to the floor surface such that the flap <NUM> functions as an element of the low-friction layer <NUM>.

When the autonomous cleaning robot moves in reverse, the flap <NUM> is in the configuration of <FIG>, with the flap <NUM> being oriented toward the forward portion <NUM> of the cleaning pad <NUM>. The fibrous material on the second side <NUM> of the flap <NUM> is exposed to the floor surface, such that the flap <NUM> ensnares debris that would otherwise move toward the forward portion <NUM> of the cleaning pad <NUM>. When the autonomous cleaning robot again moves forward, the pocket <NUM> confines the debris ensnared by the second side <NUM> of the flap <NUM>, preventing that debris from interfering with the operation of the cliff sensors.

In some examples, the low-friction layer of a cleaning pad can provide mechanical stability to the cleaning pad. For instance, some fibrous layers can be stretchable, and some low-friction layers can be substantially less stretchable, e.g., the material of the low-friction layers can have a higher elastic modulus than the material of the fibrous layers. The presence of the low-friction layer can provide a measure of resistance to stretching of the cleaning pad, e.g., stretching along the direction of motion of the autonomous cleaning robot. In some examples, the low-friction layer can be disposed on all or a portion of the top surface of a cleaning pad to provide rigidity against stretching.

Referring to <FIG>, an autonomous cleaning robot (e.g., the autonomous cleaning robot <NUM>) includes a drive (not shown) that can maneuver the autonomous cleaning robot <NUM> across the floor surface based on, for example, a drive command having x, y, and θ components.

The forward portion <NUM> of the autonomous cleaning robot <NUM> carries a movable bumper <NUM> for detecting collisions in longitudinal (e.g., forward or rear) or lateral (e.g., left or right) directions.

In some examples, the cleaning pad (not shown) extends beyond the width of the bumper <NUM> such that the autonomous cleaning robot <NUM> can position an outer edge of the cleaning pad up to and along tough-to-reach surfaces or into crevices, such as at a wall-floor interface. In some examples, the cleaning pad extends up to the edges and does not extend beyond a pad holder (not shown) of the robot. In such examples, the cleaning pad can be bluntly cut on the ends and absorbent on the side surfaces. The autonomous cleaning robot <NUM> can push the edge of the cleaning pad against wall surfaces. The position of the cleaning pad further allows the cleaning pad to clean the surfaces or crevices of a wall by the extended edge of the cleaning pad while the autonomous cleaning robot <NUM> moves in a wall following motion. The extension of the cleaning pad <NUM> thus enables the autonomous cleaning robot <NUM> to clean in cracks and crevices.

A reservoir <NUM> within the body <NUM> holds a cleaning fluid (e.g., cleaning solution, water, and/or detergent). The autonomous cleaning robot <NUM> has a fluid applicator <NUM> connected to the reservoir <NUM> by a tube. The fluid applicator <NUM> can be a sprayer or spraying mechanism including a one or more nozzles <NUM>. In some examples of the fluid applicator <NUM>, multiple nozzles are configured to spray fluid in different directions. The fluid applicator may apply fluid downward through a bottom portion of the bumper <NUM> rather than outward, dripping or spraying the cleaning fluid directly in front of the autonomous cleaning robot <NUM>. In some examples, the fluid applicator is a microfiber cloth or strip, a fluid dispersion brush, or a sprayer. In some examples, the autonomous cleaning robot <NUM> includes a single nozzle.

The cleaning pad and autonomous cleaning robot <NUM> are sized and shaped such that the process of transferring the cleaning fluid from the reservoir <NUM> to the absorptive cleaning pad maintains the forward and aft balance of the autonomous cleaning robot <NUM> during dynamic motion. The fluid is distributed so that the autonomous cleaning robot <NUM> continually propels the cleaning pad over the floor surface without the increasingly saturated cleaning pad and decreasingly occupied fluid reservoir <NUM> lifting the rear portion <NUM> of the autonomous cleaning robot <NUM> and pitching the forward portion <NUM> of the autonomous cleaning robot <NUM> downward, which can apply movement-prohibitive downward force to the autonomous cleaning robot <NUM>. Thus, the autonomous cleaning robot <NUM> is able to move the cleaning pad across the floor surface even when the cleaning pad is fully saturated with fluid and the reservoir is empty. The autonomous cleaning robot <NUM> can track the amount of floor surface travelled and/or the amount of fluid remaining in the reservoir <NUM>, and provide an audible and/or visible alert to a user to replace the cleaning pad and/or to refill the reservoir <NUM>. In some implementations, the autonomous cleaning robot <NUM> stops moving and remains in place on the floor surface if the cleaning pad is fully saturated or otherwise needs to be replaced, if there remains floor to be cleaned.

The robots and techniques described herein, or portions thereof, can be 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 described herein, or portions thereof, can be implemented as all or part of an apparatus or electronic system that can include one or more processing devices and memory to store executable instructions to implement various operations.

Operations associated with implementing all or part of the robot operation and control described herein can be performed by one or more programmable processors executing one or more computer programs to perform the functions described herein. For example, the mobile device, a cloud computing system configured to communicate with the mobile device and the autonomous cleaning robot, and the robot's controller may all include processors programmed with computer programs for executing functions such as transmitting signals, computing estimates, or interpreting signals.

The controllers and mobile devices described herein can include one or more processors. 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.

The robot control and operating techniques described herein may be applicable to controlling other mobile robots aside from cleaning robots. For example, a lawn mowing robot or a space-monitoring robot may be trained to perform operations in specific portions of a lawn or space as described herein.

Claim 1:
A cleaning pad (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) comprising:
a mounting surface (<NUM>) disposed on a top side of the cleaning pad, the mounting surface configured to provide a mechanical connection to an autonomous cleaning robot (<NUM>);
a first outer layer (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) disposed on a bottom side of the cleaning pad, the first outer layer having a first coefficient of friction; and
a second outer layer (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; 904a, 904b; <NUM>) disposed on the bottom side of the cleaning pad, the second outer layer having a second coefficient of friction less than the first coefficient of friction,
characterized in that the second outer layer is disposed forward of at least a portion of the first outer layer at a forward portion (<NUM>; <NUM>) of the cleaning pad,
wherein a surface area of the first outer layer is larger than a surface area of the second outer layer, optionally in which a ratio of the surface area of the first outer layer to the surface area of the second outer layer is between <NUM>:<NUM> and <NUM>:<NUM>.