Patent ID: 12239280

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring toFIG.1, an autonomous cleaning robot100performs an autonomous cleaning operation to in which the robot100autonomously moves about a floor surface102to clean the floor surface102by ingesting debris104located at different portions of the floor surface102. A side brush106of the robot100that extends beyond an outer perimeter of the robot100and that is rotatable in a direction of rotation108(also shown inFIG.2) to sweep debris104outside of the outer perimeter of the robot100toward a main brush120a(shown inFIG.2) on an underside of the robot100. For example, the side brush106sweeps the debris toward a region in front of the robot100or otherwise into a projected cleaning path of the robot100. During obstacle following behavior, the side brush106sweeps debris along an obstacle110as the robot100advances along a perimeter of the obstacle110and a lateral side112aof the robot100tracks the obstacle110. In the example of a robot having a rectangular front such as shown inFIG.1, the side brush106, located proximate the lateral side112a, extends beyond the lateral side112aof the robot100such that the side brush106can access debris104located along obstacles (e.g., walls, furniture, etc.) and at corners defined by obstacles. In some examples, the side brush106also extends beyond a forward surface114of the robot100.

In the example depicted inFIG.2, an arrangement of the side brush106relative to a main brush120aof the robot100is shown. A width of the main brush120adefines a cleaning width118(shown inFIG.1) of the robot100. During the autonomous cleaning operation, the main brush120ais rotated to direct debris104under the robot100into a cleaning bin122(shown schematically inFIG.1) of the robot100, and the side brush106is rotated to propel debris104toward the main brush120a. The side brush106enables the robot100to ingest debris104outside of the reach of the main brush120aof the robot100. For example, referring toFIG.1, the side brush106sweeps debris104into a projected path116of the cleaning width118of the robot100, e.g., a projected cleaning path of the robot100. The projected path116corresponds to a region within which debris104on the floor surface102will be ingested by the robot100, e.g., by a vacuum airflow, one or more rotating brushes, or a combination thereof.

As shown inFIG.2, the side brush106is rotatable to sweep the floor surface102and propel debris toward the main brush120a. The side brush106rotates about an axis of rotation124extending vertically away from the floor surface102and, in some examples, extending along an axis forming an angle less than 90 degrees with the floor surface102. As described herein, geometry of the side brush106enables the side brush106to sweep a portion of the floor surface102below the main brush120awhile the main brush120arotates to ingest debris104from the floor surface102. This allows the main brush120ato extend along a greater portion of an overall width of the robot100without resulting in disruption of operations of the main brush120aand the side brush106during the autonomous cleaning operation.

Example Autonomous Cleaning Robot

FIG.3depicts an example of the robot100. The robot100includes a front portion128that has a substantially rectangular shape. For example, the front portion128includes a region of the robot100including a bumper129of the robot100and a portion of a body131of the robot100. The forward surface114is substantially perpendicular to both of the lateral sides112a,112b, e.g., defines an angle between 85 degrees and 95 degrees with each of the lateral sides112a,112b. A rear portion130of the robot100has a substantially semicircular shape.

The robot100includes a drive system to move the robot100across a floor surface in a forward drive direction132(also shown inFIG.1). The drive system includes drive wheels134driven by motors. Two motors136are schematically shown inFIG.3, with each motor driving one of the drive wheels134. The motors136are operatively connected to a controller138(schematically shown inFIG.3) that is configured to operate the motors136to move the robot100.

The controller138is configured to operate the robot100in multiple behaviors including a coverage behavior and an obstacle following behavior. For example, when the robot100performs an autonomous cleaning operation in a space having an interior portion and a perimeter enclosing the interior portion. The perimeter is defined by obstacles, e.g., furniture, wall surfaces, etc., in the space. During the autonomous cleaning operation, the robot100selects one of its behaviors to clean the floor surface of the space. In the coverage behavior, the robot100traverses the floor surface to clean the interior portion of the enclosed space. For example, the robot100moves back-and-forth across the space, turning in response to detection of the perimeter of the enclosed space, e.g., using obstacle detection sensors of the robot100. In the obstacle following behavior, the robot100moves along a perimeter of an obstacle and hence the perimeter of the space to clean the perimeter.

As described herein, the robot100further includes the brush120a. The robot100can have a single brush or can have multiple brushes as shown inFIG.3. For example, the brush120ais one of multiple brushes120a,120bexposed to the floor surface along a bottom surface140of the robot100. The brushes120a,120bare driven to rotate by one or more motors to sweep debris on the floor surface. For example, in the example depicted inFIG.3, a single motor142is operatively connected to the controller138, which is configured to operate the motor142to drive both of the brushes120a,120b. The brushes120a,120bare configured to rotate about corresponding axes of rotation144a,144b, respectively. The axes of rotation144a,144bare parallel to the floor surface along which the robot100moves.

During the autonomous cleaning operation, the brushes120a,120bare driven to rotate in opposite directions such that each brush120a,120bdraws debris toward an inlet146to a pathway to the cleaning bin122. The inlet146can be a space between the brush120aand the brush120b. In some examples, the inlet146can be a space between the brush120aor the brush120band a housing188, e.g., to which the brushes120a,120bare mounted. For example, the robot100can include no more than one brush. The robot100includes a single brush, e.g., either the brush120aor the brush120b, and an inlet to the pathway to the cleaning bin122can be a space between the brush and the housing188.

The robot100includes a vacuum system148operable by the controller138to generate an airflow from at least the inlet146through the pathway to the cleaning bin122, thereby collecting debris proximate the inlet146in the cleaning bin122. The vacuum system148generates a negative pressure to create the airflow that carries debris drawn into the pathway by the brushes120a,120b. The rotation of the brushes120a,120bdirects debris on the floor surface toward the inlet146to enable the vacuum system148to carry the debris into the cleaning bin122.

The brushes120a,120bare each disposed in the front portion128of the robot100. This enables the widths of the brushes120a,120bto extend along a greater portion of a maximum width W1of the robot and closer to the front of the robot100, e.g., as compared to cases in which brushes are disposed in narrower portions of the semicircular rear portion130of the robot100or located near the center of the robot100near the wheels134. While a diameter of the semicircular rear portion130of the robot100has the width W1, the front portion128has a width W1through nearly its entire length, e.g., through at least 90% or more of the length of the front portion128. In this regard, in some implementations, the brushes120a,120bare disposed only in the front portion128of the robot100so that the brushes120a,120bcan extend across a greater portion of the width W1. In some examples, the width W1corresponds to a width of the front portion128. The width W1is between, for example, 20 cm and 40 cm (e.g., between 20 cm and 30 cm, between 25 cm and 35 cm, between 30 cm and 40 cm, or about 30 cm.). The brushes120a,120bextend across a width W2that is between, for example, 15 cm and 35 cm (e.g., between 15 cm and 25 cm, between 20 cm and 30 cm, between 25 cm and 35 cm, or about 25 cm). The width W2is 60% to 90% of the width W1of the robot100(e.g., between 60% and 80%, between 65% and 85%, between 70% and 90%, between 75% and 90%, between 80% and 90%, or about 75% of the width W1).

As described herein, the robot100further includes the side brush106(also referred to as a corner brush when placed in a corner), which is rotatable to sweep debris toward the brushes120a,120bof the robot100. The side brush106thus cooperates with the brushes120a,120band the vacuum system148to collect debris from the floor surface in the cleaning bin122.

The side brush106extends outwardly away from the robot100and away from the bottom surface140of the robot100. The side brush106is mounted to a motor150of the robot100, the motor150being operatively connected to the controller138. The controller138is configured to operate the motor150to rotate the side brush106, which sweeps debris on a floor surface toward the brushes120a,120b. The side brush106extends across a width W3between 2 cm and 12 cm (e.g., between 2 cm and 12 cm, between 2 cm and 4 cm, between 4 cm and 12 cm, between 6 cm and 10 cm, between 7 cm and 9 cm, about 3 cm, or about 8 cm). The width W3is between 15% and 35% of the width W1of the robot100(e.g., between 15% and 25%, between 20% and 30%, between 25% and 35%, or about 25% of the width W1). The width W3is between 5% and 40% of the width W2of the brushes120a,120b(e.g., between 5% and 15%, between 10% and 20%, between 20% and 30%, between 25% and 35%, between 30% and 40%, about 10%, or about 30% of the width W1). A width W4corresponding to a portion of the width W2of the brushes120a,120bthat overlaps the width W3of the side brush106is between, for example, 0.5 cm and 5 cm (e.g., between 0.5 and 1.5 cm, between 1.5 cm and 4 cm, between 2 cm and 4.5 cm, between 2.5 cm and 5 cm, about 1 cm, or about 2.5 cm).

The side brush106is located proximate one of the lateral sides112a,112bof the robot100. In the example depicted inFIG.3, the side brush106is located proximate the lateral side112asuch that at least a portion of the side brush106extends beyond the lateral side112aduring rotation of the side brush106. A center of the side brush106is mounted between 1 cm and 5 cm from the lateral side112a(e.g., between 1 and 3 cm, between 2 and 4 cm, between 3 and 5 cm, or about 3 cm from the lateral side112a). The side brush106extends beyond the lateral side112aby between 0.25 cm and 2 cm (e.g., at least 0.25 cm, at least 0.5 cm, at least 0.75 cm, between 0.25 cm and 1.25 cm, between 0.5 cm and 1.5 cm, between 0.75 cm and 1.75 cm, between 1 cm and 2 cm, or about 1 cm).

The side brush106is also located proximate the forward surface114such that at least a portion the side brush106extends beyond the forward surface114of the robot100during rotation of the side brush106. In some examples, the center of the side brush106is mounted between 1 and 5 cm from the forward surface114(e.g., between 1 and 3 cm, between 2 and 4 cm, between 3 and 5 cm, or about 3 from the forward surface114). The side brush106extends beyond the forward surface114by between 0.25 cm and 2 cm (e.g., at least 0.25 cm, at least 0.5 cm, at least 0.75 cm, between 0.25 cm and 1.25 cm, between 0.5 cm and 1.5 cm, between 0.75 cm and 1.75 cm, between 1 cm and 2 cm, about 1 cm, or about 0.75 cm.).

By being proximate the lateral side112aand the forward surface114, the side brush106is thus located proximate a corner portion152of the robot100, the corner portion152being defined by the lateral side112aand the forward surface114. In some cases, the corner portion152includes a rounded portion connected by the lateral side112aand the forward surface114, with a segment of the corner portion152defined by the lateral side112aand a segment of the forward surface114forming substantially a right angle. The corner portion152can fit into corresponding corner geometries found in a home, e.g., defined by obstacles. For example, the corner portion152can fit into corresponding right-angled geometries defined by obstacles in the home.

By being positioned such that at least a portion of the side brush106extends beyond both the forward surface114and the lateral side112a, the side brush106can easily access and contact debris on a floor surface outside of a region directly beneath the robot100. For example, the side brush106can access debris outside of the projected path116(shown inFIG.1) of the brushes120a,120bsuch that the side brush106can contact the debris and propel the debris into the projected path of the brushes120a,120b. As the robot100travels along the floor surface, the side brush106can enable the robot100to collect debris forward of the forward surface114and adjacent to the lateral side112a. Furthermore, the side brush106can sweep debris adjacent to the corner geometries toward the brushes120a,120bso that the brushes120a,120bcan ingest the debris. In some cases, the side brush106extends forward of a forwardmost point of the forward surface114of the robot100. In such examples, the side brush106can engage debris adjacent to an obstacle forward of the robot100.

In some examples, the robot100includes a cleaning head module154that includes the brushes120a,120b. The cleaning head module154further includes the one or more motors to drive the brushes120a,120b. In some implementations, the cleaning head module154further includes the side brush106(shown inFIG.3) and the one or more motors to drive the side brush106. The side brush106is mounted proximate a corner portion156of the cleaning head module154. For example, the side brush106is mounted between 0.5 cm and 2.5 cm from the corner portion156(e.g., between 0.5 cm and 1.5 cm, between 1 cm and 2 cm, between 1.5 cm and 2.5 cm, about 1.5 cm). The cleaning head module154, including the housing188, the brush or brushes120a,120b, motor(s), and the side brush106, can be removed as a complete unit and replaced if needed.

The side brush106is mountable to a drive shaft157connected to the motor150that drives the side brush106. As depicted inFIG.4, the side brush106is removable from the cleaning head module154and thus dismountable from the drive shaft157.

The cleaning head module154is mountable, as a unit, to the rest of the robot100and is also dismountable, as a unit, from the rest of the robot100. In some cases, the cleaning head module154is mounted at least partially within the body131(shown inFIG.3) of the robot100. This can make maintenance of the cleaning head module154easier to perform. For example, the cleaning head module154, including its brushes120a,120b, can be easily replaced by a new cleaning head module with new brushes. In addition, the cleaning head module154can be movable relative to the chassis of the robot100such that the cleaning head module154can move in response to contact with obstacles along the floor surface over which the robot100moves or in response to a change in flooring type. If the side brush106is disposed on the cleaning head module154, contact between the side brush106and obstacles on the floor surface can also cause the cleaning head module154to move. This can prevent damage to the brushes120a,120b, the side brush106, and the cleaning head module154.

Referring toFIGS.5A and5B, during the obstacle following behavior, the robot100travels adjacent a perimeter158of an obstacle160asuch that the lateral side112ais positioned adjacent the perimeter158. By being positioned proximate the lateral side112a, the side brush106is positioned to reach debris along the perimeter158of the obstacle160aduring the obstacle following behavior. For example, the lateral side112acorresponds to a dominant obstacle-following side of the robot100such that the controller138(shown inFIG.3) repositions the robot100so that the lateral side is adjacent to the followed object or wall.

As shown inFIG.3, the robot100includes multiple cliff sensors137a-137f. The cliff sensors137a-137fare configured to provide a signal when a floor surface does not occupy the region below one or more of the cliff sensors137a-137f. For example, the cliff sensors137a-137fcan be infrared emitter and receiver pairs having overlapping fields of view configured to identify when a floor surface is present beneath the cliff sensors137a-137fand redirect the robot100when the floor surface is not present (e.g., redirect the robot100away from a cliff such as a stair).

In the example ofFIG.3, the side brush106is located in the corner portion152. The location of the side brush106and its associated motor causes the brushes120a,120bto be offset from the center of the robot. For example, the brushes120a,120bare located closer to the lateral side112bthan the lateral side112aby 0.5 cm to 2.5 cm (e.g., by 0.5 to 1.5 cm, 1 cm to 2 cm, 1.5 cm to 2.5 cm, or about 1 cm). Additionally, by locating the brushes120a,120bclose to the lateral side112b(e.g., within about 3 cm), the cliff sensor137blocated on the lateral side112bis placed behind the brushes120a,120b(e.g., behind the brushes and ahead of the wheel134) while the cliff sensor137eis located proximate the brushes120. Thus, the side cliff sensors137band137eare not symmetrically located about a fore-aft axis FA of the robot100. The robot100also includes four additional cliff sensors137a,137c,137d, and137f. Two cliff sensors137cand137dare located proximate a front surface114ahead of the brushes120a,120band two cliff sensors137aand137flocated rear of the wheels134. The forward cliff sensors137c,137dand rear cliff sensors137a,137fcan be symmetrically located about the fore-aft axis FA.

The side brush106is rotatable through a cleaning area162. Because the side brush106extends beyond the lateral side112aand the forward surface114, the cleaning area162extends beyond the lateral side112aand the forward surface114. As a result, the side brush106is configured to engage debris within the cleaning area162on the floor surface102so that the debris can be swept toward the projected path116of the cleaning width118of the robot100. For example, the side brush106cooperates with the brushes120a,120band the vacuum system148to collect, within the cleaning bin122(shown inFIG.3), debris beyond a perimeter of the robot100. The cleaning width118does not extend into a portion164of the floor surface102adjacent the perimeter158of the obstacle160a. At least some of the portion164is located under the robot100because the projected path116does not extend the entire width W1of the robot100. In this regard, the brushes120a,120band the vacuum system148of the robot100(shown inFIG.3) cannot collect debris within the portion164of the floor surface102unless this debris is moved into the projected path116. The side brush106, when rotated, can facilitate this movement of the debris. For example, the side brush106reaches debris within the cleaning area162and thus sweeps the debris in the portion164toward the projected path116, thereby enabling the robot100to collect debris located within the portion164.

Furthermore, as shown inFIG.5B, because the side brush106extends beyond both the forward surface114and the lateral side112a, the side brush106is configured to extend into a corner166defined by the intersection of the obstacles160a,160b. The corner166can be difficult to clean for the robot100due to the geometry of the outer perimeter of the robot100and due to the positioning of the brushes120a,120bwithin the outer perimeter. The side brush106extends beyond the outer perimeter to enable debris to be collected from the corner166and other complex obstacle perimeter geometries, e.g., curves, crevasses, etc.

Example Side Brush

FIGS.6A-6Edepict an example of the side brush106. This example is described with respect to the X-axis, the Y-axis, and the Z-axis. The axis of rotation124of the side brush106is parallel to the Y-axis. As described herein, in some cases, the Y-axis is parallel to a vertical axis extending perpendicularly from the floor surface, while in other implementations, the Y-axis and the vertical axis form a non-zero angle.

Referring toFIG.6A, the side brush106includes a hub168, arms170, and bristle bundles172. The side brush106is axisymmetric about the axis of rotation124. The side brush106is mounted such that it can sweep a portion of the floor surface under the robot100to propel debris on the floor surface toward the brushes120a,120bas the side brush106rotates about the axis of rotation124. The portion of the floor surface swept by the side brush further includes a portion directly beneath at least one of the brushes120a,120b. As described herein, the hub168, the arms170, and the bristle bundles172are configured such that the side brush106can sweep under the brushes120a,120bwithout interfering with operation of the brushes120a,120b.

Referring toFIG.6B, the hub168includes a semispherical body171having a circular cross-section, e.g., along a plane perpendicular to the axis of rotation124. In some examples, a circle O1(shown inFIG.6E) is defined by an outer perimeter of the hub168as viewed along the Y-axis. The circle O1has a diameter D1(shown inFIG.6E) between 1 cm and 3 cm (e.g., between 1 cm and 2 cm, between 1.5 cm and 2.5 cm, between 2 cm and 3 cm, or about 2 cm).

The hub168is configured to engage a side brush motor (e.g., the motor150) of the robot100(shown inFIG.3). For example, as shown inFIG.6A, the hub168includes a bore175sized and dimensioned to engage the drive shaft157(shown inFIG.4). The bore175, when engaged to the drive shaft157, enables transfer of torque from the side brush motor to the hub168such that the side brush motor can rotate the side brush106. In some cases, at least a portion of the hub168is positioned above the bottom surface140of the robot100(shown inFIG.3).

A height H1(shown inFIG.6C) of the hub168is between 0.25 cm and 1.5 cm (e.g., between 0.25 cm and 1 cm, 0.5 cm and 1.25 cm, 0.75 and 1.5 cm, or about 0.75 cm). For example, the height H1is defined by the lowest point at which the arms170is attached to the hub168and the topmost surface of the bore175. Because the hub168is a rigid plastic component, an impact force on the hub168can transfer to the drive shaft157without substantial attenuation. As a result, the impact force on the hub168can damage the drive shaft157. The height H1is relatively small so that the hub168is less likely to contact obstacles along the floor surface. The relatively small height of the hub168can thus prevent damage to the drive shaft157or the side brush motor. As described herein, the hub168can be part of the cleaning head module154. As a result, impact on the hub168can cause the cleaning head module154as a unit to move, thereby dampening the force of the impact and preventing damage to the side brush106due to the impact.

The hub168, the arms170, and the bristle bundles172can be formed of different materials. For example, the hub168is a monolithic plastic component from which the arms170, the bristle bundles172, or both extend. The hub168is formed from a rigid polymer material having an elastic modulus between 1 and 10 GPa, and the arms170are formed from an elastomeric material having an elastic modulus between 0.01 and 0.1. For example, the hub168is formed from polycarbonate or acrylonitrile butadiene styrene, and the arm170is formed from an elastomer. The arms170are thus more easily deformable than the hub168. The arms170serve as a protective sheath for the bristle bundles172that keep bristles of each of the bristle bundles172together while also being deformable such that the bristle bundles172and the arms170can deform together in response to contact with the floor surface and obstacles on the floor surface. As a result, the arms170can prevent the bristle bundles172from being damaged.

Referring toFIG.6C, the arms170extend outwardly from the hub168away from the axis of rotation124of the side brush106. The arms170each extends along a length L1(shown inFIG.6D) between 0.5 cm and 2.5 cm (e.g., between 0.5 cm and 1.5 cm, between 1 cm and 2 cm, between 1.5 cm and 2.5 cm, or about 1.5 cm.). The length L1corresponds to a straight line length from a proximal end177ato a distal end177bof each arm170, with the proximal end177abeing attached to the hub168.

Each of the arms170is angled relative to a plane173normal to the axis of rotation124of the brush106. The arms170are formed of two portions174,176that are angled differently with respect to the plane173. The differently angles portions174,176allow the arm170both to span a vertical distance between the robot100and the floor surface and form a desired swept circle for the bristle bundles172. For example, a slope of the portion174of the arms170(relative to the plane173) closest to the hub168is greater than a slope of the portion176of the arms170(relative to the plane173) further from the hub168.

The first portion174and the second portion176each extends downwardly toward a floor surface when the side brush106is mounted to the drive shaft157. In this regard, while the height H1of the hub168may be small so that the hub168is positioned above the floor surface by a clearance height, the first portion174and the second portion176extend downwardly to enable the bristle bundles172to contact the floor surface.

The first portion174and the second portion176also each extends outwardly from the hub168, e.g., in a direction along the plane173. The first portion174is attached to the hub168at the proximal end177aof each arm170and extends outwardly from the hub168away from the axis of rotation124. The second portion176extends outwardly from the first portion174away from the axis of rotation124and terminates at the distal end177bof each arm170. For example, referring toFIG.6D, the first portion174and the second portion176both extend outwardly away from the axis of rotation124such that the distal end177bof each arm170is swept through a circle O2when the side brush106is rotated about the axis of rotation124. The circle O2corresponds to a circle swept by an outer point of the distal end177bof each arm170when viewed along the Y-axis. The circle O2has a diameter D2between 2 cm and 4 cm (e.g., between 2 cm and 3 cm, between 2.5 cm and 3.5 cm, between 3 cm and 4 cm, or about 3 cm). By each extending outwardly away from the axis of rotation124, the first portion174and the second portion176allow the side brush106to extend outwardly from the robot100, e.g., to extend and cover an area beyond the outer perimeter of the robot100and to cover an area outside of the cleaning width of the robot100and beneath the robot100.

Referring back toFIG.6C, the first portion174extends downwardly from the hub168. In some examples, the second portion176also extends downwardly from the first portion174. By extending downwardly from the hub168, the arms170enable the bristle bundles172to be positionable to contact the portion of the floor surface below the side brush106. For example, a height H2of each arm170between the proximal end177a(e.g., a lowermost point of the proximal end177a) and the distal end177b(e.g., a lowermost point of the distal end177b) is between 0.25 and 1.5 cm (e.g., between 0.25 cm and 1 cm, 0.5 cm and 1.25 cm, 0.75 cm and 1.5 cm, or about 0.8 cm).

In some examples, an angle A1between the first portion174of each of the arms170and the plane173is larger than an angle A2between the second portion of the each of the arms and the plane173. The angle A1and the angle A2correspond to angles as measured within the X-Y plane when the axis along which the second portion176extends parallel to the X-axis. The first portion174of each of the arms170is angled upward relative to the second portion176such that the first portion174has a shallower angle relative to the plane173than the steeper angle of the second portion176relative to the plane173. The angle A1is between 70 and 90 degrees (e.g., between 70 and 80 degrees, between 75 degrees and 85 degrees, between 80 degrees and 90 degrees, or about 80 degrees). The angle A2is between 0 and 60 degrees (e.g., between 15 and 60 degrees, between 15 and 45 degrees, between 15 and 30 degrees, or about 30 degrees).

The second portion176of each of the arms170is angled relative to the first portion174in a direction opposite the direction of rotation108of the side brush106. For example, referring toFIG.6E, each of the arms170extends from a portion of the hub168along the circle O1. An angle A3corresponds to an angle between (i) an axis along the X-Z plane and along which the second portion176of an arm170extends and (ii) a line181tangent to the circle O1and extending through the point at which the axis of the second portion176intersects the circle O1. The angle A3is between, for example, 30 and 60 degrees (e.g., between 30 and 50 degrees, 35 and 55 degrees, 40 and 60 degrees, etc.). In some cases, the first portion174of each of the arms170extends along a radial axis and thus is substantially perpendicular to the tangent line181. This angle of the second portion176relative to the tangent line181can reduce stress concentrations along the arms170when the arms170deflect during rotation of the side brush106.

In some implementations, referring back toFIG.6B, an angle A4between the first portion174of each of the arms170and the second portion176of each of the arms170is between 100 and 160 degrees (e.g., between 100 and 140 degrees, between 110 and 150 degrees, between 120 and 160 degrees, or about 130 degrees). The bristle bundles172each includes multiple bristles that sweep the floor surface as the side brush106is rotated during the autonomous cleaning operation. Referring back toFIG.2, the bristle bundles172of the side brush106can sweep the floor surface102and propel debris toward the main brush120a. Each of the bristle bundles172is repositioned as the side brush106is rotated. For example, at least a portion of the bristle bundles172, e.g., the bristle bundle172a, as shown inFIG.2, is positionable below the main brush120aduring a portion of the rotation of the side brush106and during rotation of the main brush120a.

In the example depicted inFIGS.6A-6E, the bristle bundles172extend from the arms170along an axis at a non-zero angle relative to an axis perpendicular to the axis of rotation124, e.g., an axis extending through a radius of any of the concentric circles O1, O2, or O3. In some implementations, each of the bristle bundles172extend parallel to the perpendicular axis. The bristle bundles172each includes multiple deflectable fibers assembled in a bundle.

Referring toFIG.6B, each of the bristle bundles172extends from a corresponding second portion176of the arms170, each bristle bundle172terminating at a corresponding distal end180. The bristle bundles172extend from the arms170along axes parallel to the axes along which the second portions176of the arms170extend. A length L2of the bristle bundles172beyond the arms170(shown inFIGS.6B and6D) is between 1 cm and 5 cm (e.g., between 1 cm and 4 cm, between 1.5 cm and 4.5 cm, between 2 cm and 5 cm, about 2.5 cm, or about 3 cm.). The length L2corresponds to a straight line length from the distal end177bof each arm170to the distal end180of each bristle bundle172. The length L2is 40% and 80% of the length L1of the arms170(e.g., between 40% and 60%, between 50% and 70%, between 60% and 80%, about 50%, about 60%, or about 70% of the length L1of the arms170). A height H3of each bristle bundle172between the distal end177bof each arm170(e.g., a lowermost point of the distal end177b) and the distal end180of each bristle bundle172is between 0.25 and 2 cm (e.g., between 0.25 cm and 1.5 cm, between 0.5 cm and 1.75 cm, between 0.75 cm and 2, or about 1 cm).

At least the distal end180of each bristle bundle172is configured to engage the floor surface and engage debris on the floor surface to propel the debris toward the brushes of the robot100(shown inFIG.2). In this regard, referring briefly back toFIG.2, at least a portion of each of the bristle bundles172is positionable beyond the front surface114and the lateral side112aof the robot100.

Referring toFIG.6D, the distal end180of each bristle bundle172is swept through a circle O3, which corresponds to a circle swept by the distal end180of each bristle bundle172when viewed along the Y-axis. The circle O3is defined by a diameter D3. In some cases, if the side brush106is mounted such that its axis of rotation124is parallel to the vertical axis, the diameter D3is equal to the width W3(shown inFIG.3). Alternatively, if the side brush106is mounted at an angle relative to the vertical axis, the diameter D3may differ from the width W3. In this regard, the diameter D3is between, for example, 2 cm and 10 cm (e.g., between 2 cm and 6 cm, between 6 cm and 10 cm, between 7 cm and 9 cm, or about 8 cm). In some cases, the diameter D1(shown inFIG.6E) is between 10% and 40% of the diameter D3(e.g., between 10% and 30%, 15% and 35%, 20% and 40%, or about 25% of the diameter D3.). In some cases, the diameter D2is between 20% and 50% of the diameter D3(e.g., between 20% and 40%, 25% and 45%, or 30% and 40% of the diameter D3.).

In some cases, the bristle bundles172are attached to the arms170, the hub168, or both. For example, a proximal end (not shown) of the bristle bundles172is attached to the arms170or the hub168. Alternatively or additionally, the bristle bundles172extend through the arms170and are attached to the arms170along the length or a portion of the length of the arms170.

Referring toFIG.7A, a top portion182of the hub168is configured to collect filament debris engaged by the side brush106. During an autonomous cleaning operation, filament debris, including hair, threads, carpet fibers, etc., can wrap around the side brush106during rotation of the side brush106. The filament debris, if wrapped around the arms170or the bristle bundles172, can impede operations of the side brush106. The filament debris can also impede operations of the side brush motor if the filament debris is wrapped around the drive shaft of the side brush motor. The top portion182of the hub168is configured such that the filament debris is collected in a region away from the arms170and the bristle bundles172.

As shown inFIGS.7A-7C, the top portion182of the hub168includes an inset portion184to collect filament debris engaged by the side brush106. Due to the angles of the arms170and the bristle bundles172relative to the axis of rotation124(shown inFIG.6A), the filament debris tends to gather toward the top portion182of the hub168. Referring also toFIGS.4and8, the cleaning head module154includes an opening186that is also configured to collect the filament debris. The drive shaft157extends through the opening186. In this regard, the side brush106is mounted at the opening186to the drive shaft157.

As shown inFIG.8, the inset portion184of the hub168is positioned to receive the filament debris, and the opening186is positioned to receive the filament debris from the inset portion184. The inset portion184and an inset portion187along the housing188define a region where the filament debris is collected. The housing188can be a housing of the cleaning head module154or a housing of the robot100. Barriers190circumferentially arranged about the opening186extend through the inset portion187to inhibit the filament debris from moving beyond the region defined by the inset portion184and the inset portion187. If the filament debris moves beyond this region, the filament debris is collected in the opening186. For example, the filament debris is collected around the drive shaft157.

To remove the filament debris collected by the side brush106, the side brush106is dismounted from the drive shaft157. The filament debris tends to collects outside of the opening186due to the barriers190, thereby making the process of removing the filament debris easier. For example, the region defined by the inset portion184and the inset portion187is easily manually accessible once the side brush106is dismounted. The user can dismount the side brush106and manually remove the filament debris from the region.

Other Implementations

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made.

For example, while the side brush106is described as extending beyond the forward surface114and the lateral side112aof the robot100, in some implementations, the side brush106extends beyond only the forward surface114of the robot100or only the lateral side112aof the robot100.

The hub168of the side brush106is shown inFIG.2as being positioned forward of the brushes120a,120b. For example, the hub168is forward of both of the axes of rotation144a,144b. In some implementations, the hub168is positioned horizontally adjacent to the brushes120a,120b. In some implementations, the side brush106is positioned rearward of the brushes120a,120b, e.g., such that the hub168is mounted rearward of the brushes120a,120b.

As depicted inFIG.2, the axis of rotation124is substantially perpendicular to the floor surface (e.g., the axis of rotation124is substantially vertical). For example, the axis of rotation124and the floor surface form an angle between 85 degrees and 90 degrees. Alternatively, in some implementations, the axis of rotation124is at a non-zero angle relative to a vertical axis. For example, the axis of rotation124and the floor surface form an angle less than 85 degrees (e.g., between 60 and 85 degrees, 70 and 80 degrees, about 75 degrees, etc.). In this regard, the axis of rotation124and a vertical axis form an angle greater than 5 degrees (e.g., between 5 and 30 degrees, 10 and 20 degrees, about 15 degrees, etc.)

In some implementations, the brushes120a,120binclude rollers having outer surfaces that engage and brush debris on the floor surface. The outer surface can be, for example, cylindrical. In some cases, the brushes120a,120binclude bristles to engage and brush debris.

While the side brush106and the brushes120a,120bare described as being driven by multiple motors, in some implementations, the side brush106and the brushes120a,120bare driven by a single motor. The robot100includes a drivetrain to transfer torque from the motor to each of the brushes106,120a,120b. Alternatively, the robot100includes three distinct motors, each configured to drive a corresponding one of the brushes106,120a,120b.

While the robot100is depicted inFIG.3as including two brushes120a,120b, in some implementations, a robot includes a single brush rotatable about an axis parallel to the floor surface. The single brush directs debris on the floor surface toward a bin of the robot. Furthermore, while the brushes120a,120bare depicted as having equal widths W2, in some implementations, one of the brushes is longer than the other of the brushes. For example, one brush has a width that is 70% to 90% of the width of the other brush.

While the robot100is depicted inFIG.3as including a single side brush106, in some implementations, the robot100includes multiple side brushes. For example, one of the side brushes is located proximate the lateral side112a, while the other of the side brushes is located proximate the lateral side112b. In some implementations, if the robot100includes multiple side brushes, either of the lateral sides112a,112bis placed adjacent the obstacle during the obstacle following behavior. The robot100does not have a dominant obstacle-following side. In this regard, to clean adjacent an obstacle, the robot100does not need to be reoriented so that a dominant side of the robot100is placed adjacent the obstacle.

While the side brush106is shown and described as a corner brush being positioned proximate the right lateral side112aof the robot100, in some implementations, the corner brush can be positioned instead on the left lateral side112bof the robot100. The dominant obstacle-following side of the robot100can correspond to a left side of the robot100rather than a right side of the robot100.

While the side brush106is shown and described as a corner brush being positioned proximate the right lateral side112aof the robot100, in some implementations, the robot can include two corner brushes with one positioned on the right lateral side and the other on the left lateral side112bof the robot100.

In some additional examples, the robot100can be square in shape and include four corner brushes with one positioned on or near each of the corners. Having four corner brushes would allow the robot100to move in the forward or backward direction while still sweeping dirt into the path from beyond the perimeter of the robot100.

While the arms170ofFIGS.6A-6Eare described as extending outwardly from the hub168away from the axis of rotation124of the side brush106, in some implementations, the arms170extend substantially radially outwardly from the hub168away from the axis of rotation124. For example, the arms170extend along axes radiating from the axis of rotation124along a plane normal to the axis of rotation124. In some cases, at least the first portion174of each arm170extends along a radial axis, e.g., downward and along the radial axis. The second portion176extends along an axis at a non-zero angle relative to the radial axis, e.g., downward and along the axis.

In the example depicted inFIGS.6A-6E, the side brush106includes five distinct arms170and five corresponding distinct bristle bundles172. However, in other implementations, a side brush can include two, three, four, six, or more distinct arms and distinct bristle bundles. While the depicted example shows a single bristle bundle per arm, in alternative implementations, a side brush can include two or more bristle bundles per arm.

Accordingly, other implementations are within the scope of the claims.