Cleaning system for autonomous robot

An autonomous cleaning robot comprises a chassis, at least one motorized drive wheel mounted to the chassis and arranged to propel the robot across a surface, and a pair of cleaning rollers mounted to the chassis and having outer surfaces exposed on an underside of the chassis and to each other. The cleaning rollers are drivable to counter-rotate while the robot is propelled, thereby cooperating to direct raised debris upward into the robot between the rollers. A side brush is further mounted to the chassis to rotate beneath the chassis adjacent a lateral side of the chassis about an upwardly extending side brush axis, and the outer surface of a first of the cleaning rollers of the pair extends laterally beyond the outer surface of a second of the cleaning rollers of the pair and laterally beyond the side brush axis, such that the first cleaning roller defines a cleaning width spanning the side brush axis.

TECHNICAL FIELD

This invention relates to autonomous cleaning robots, such as those used for cleaning floors.

BACKGROUND

Autonomous floor-cleaning robots clean floor surfaces without direct and continuous human intervention and operation. Some clean by sweeping debris from the floor, and ingesting the debris as they travel. Some include vacuum systems that help to draw debris into the robot. Such robots may operate on hard floor surfaces, or on floor surfaces formed by carpeting or rugs. It is desired that such robots be able to clean as close to walls and other obstacles, and as far into corners, as possible.

SUMMARY

In one aspect of the invention, an autonomous cleaning robot includes a chassis, at least one motorized drive wheel mounted to the chassis and arranged to propel the robot across a surface, and a pair of cleaning rollers mounted to the chassis and having outer surfaces exposed on an underside of the chassis and to each other. The cleaning rollers are drivable to counter-rotate while the robot is propelled, thereby cooperating to direct raised debris upward into the robot between the rollers. A side brush is further mounted to the chassis to rotate beneath the chassis adjacent a lateral side of the chassis about an upwardly extending side brush axis. The outer surface of a first of the cleaning rollers of the pair extends laterally beyond the outer surface of a second of the cleaning rollers of the pair and laterally beyond the side brush axis, such that the first cleaning roller defines a cleaning width spanning the side brush axis. In other implementations, a motor is operably connected to the side brush and at least one of the cleaning rollers, such that operation of the motor turns the side brush and at least one of the cleaning rollers.

In some examples, the outer surface of the first of the cleaning rollers of the pair extends laterally beyond the outer surface of the second of the cleaning rollers by at least about one inch. A ratio of a length of the first of the cleaning rollers to a length of the second of the cleaning rollers may be between about 10:9 and 2:1, for example. In some cases, the first of the cleaning rollers of the pair includes two roller segments disposed to rotate about a common axis.

Some embodiments have first, second, and third sensors mounted to the chassis and responsive to radiation reflected upward from a floor surface beneath the sensors. The first sensor may be disposed near a front corner of the robot, the second sensor near a front portion of the robot near the side brush, and the third sensor on a near portion of the robot near the side brush, for example.

In some examples, the side brush includes a plurality of downwardly extending bristles arranged in a circular configuration that covers between 60% and 90% of the total perimeter of the circle.

The upwardly extending side brush axis may form an angle less than 90 degrees with the underside of the chassis.

In some implementations, the side brush includes multiple discrete bristle tufts arranged in a circular configuration, with bristle-free regions between the discrete bristle tufts. The bristle-free regions may be between 10% and 30% of the total perimeter of the circle defined by the circular configuration of discrete bristle tufts. In some cases a cliff sensor is mounted to the chassis and is responsive to radiation reflected upward from a floor surface beneath the cliff sensor. The side brush bristle tufts are configured to sweep through an area directly beneath the cliff sensor. In some cases the side brush is arranged such that during rotation of the side brush bristles of the side brush sweep under the outer surfaces of both cleaning rollers of the pair.

In some examples, at least one of the cleaning rollers includes or is a roller brush with a roller core and bristles extending from the core to define the outer surface of the roller brush. In some implementations, each of the cleaning rollers is or includes a roller brush. During counter-rotation of the cleaning rollers, bristles of the first cleaning roller may extend into space between bristles of the second cleaning roller brush. In other implementations, only one of the cleaning rollers is or includes a roller brush, while the other of the cleaning rollers is free of bristles.

In some examples, the outer surface of at least one of the rollers includes an elastomeric polymer. The elastomeric polymer may form exposed surfaces of raised features of the outer surface, for example. In some cases the elastomeric polymer is in the forth of a sheath over a resilient layer.

In some implementations, the chassis has a forward outer edge segment that is linear. The forward outer edge segment is preferably generally parallel with the pair of cleaning rollers over at least a central 90% of the width of the chassis. The side brush may be arranged such that during rotation of the side brush bristles of the side brush sweep beyond the forward outer edge segment. The chassis may also have an outer side edge segment, on a side closest to the side brush, which is linear and generally perpendicular to the forward outer edge segment. The direction of rotation of the side brush may be chosen such that the time required for a portion of the side brush to sweep first under the lateral side and then under the forward outer edge segment is greater than the time required for the portion of the side brush to sweep first under the forward outer edge segment and then under the lateral side.

The first of the cleaning rollers of the pair preferably extends across at least 75% of an overall width of the cleaning robot.

The cleaning rollers together preferably cover a floor area at least 10% percent of a total floor area covered by the robot.

In most cases the cleaning rollers are configured to rotate about respective, parallel roller rotation axes. The upwardly extending side brush axis may be disposed forward of at least one of the roller rotation axes, with respect to a forward drive direction of the cleaning robot. In some examples a distance between the roller rotation axes is greater than half the sum of the diameters of the cleaning rollers. In some cases, at least one of the cleaning rollers of the pair is arranged to rotate around an axis disposed forward of the at least one motorized drive wheel, and preferably within a distance of a forward edge of the cleaning robot that is less than twice a diameter of the forward roller.

In most cases, the pair of rollers will have different lengths. Configuring the rollers such that one of the rollers in the pair (e.g., the rear roller in the direction of travel) extends beyond the axis of the side brush, can facilitate sweeping of debris by the side brush into the cleaning path of the robot, while maintaining an overall effective cleaning path width that is substantial with respect to an overall width of the robot. Debris encountered outside of the cleaning path defined by the pair of rollers can be effectively repositioned such that driving the robot forward allows the cleaning rollers to engage the debris for ingestion into the robot.

DETAILED DESCRIPTION

An autonomous robot movably supported can clean a surface while traversing that surface. The robot can remove debris from the surface by agitating the debris and/or lifting the debris from the surface by applying a negative pressure (e.g., partial vacuum) above the surface, and collecting the debris from the surface. The robot can include a cleaning system of rollers and brushes that agitate debris and facilitate the intake of the debris. As will be described in detail below, the configuration of the rollers and brush(es) can be used to ensure that the robot can collect debris from corners and crevasses and places otherwise difficult to reach for the robot.

FIGS. 1-8, by way of general overview, pertain to an implementation of an autonomous cleaning robot100.FIG. 1A-Bshows perspective and bottom views, respectively, of the robot100. Referring toFIG. 1A, robot100includes a body110, a forward portion112, and a rearward portion114. The robot100can move across the floor surface through various combinations of movements relative to three mutually perpendicular axes defined by the body110: a transverse axis X, a fore-aft axis Y, and a central vertical axis Z. A forward drive direction along the fore-aft axis Y is designated F (referred to hereinafter as “forward”), and an aft drive direction along the fore-aft axis Y is designated A (referred to hereinafter as “rearward”). The transverse axis X extends between a right side R and a left side L of the robot100substantially along an axis defined by center points of, referring briefly toFIG. 1B, the wheel modules120a,120b. The forward portion112has a front surface103that is generally perpendicular to side surfaces104a-bof the robot100. Referring briefly to bothFIGS. 1A and 1B, rounded surfaces107a-bconnect the front surface103to the side surfaces104a-b. The front surface103is at least 90% of the width of the robot body. The rearward portion114is generally rounded, having a semicircular cross section. A user interface138disposed on a top portion of the body110receives one or more user commands and/or displays a status of the robot100. Sonar sensors530adisposed on the forward portion112serve as transducers of ultrasonic signals to evaluate the distance of obstacles to the robot100. The forward portion112of the body110further carries a bumper130, which detects (e.g., via one or more sensors) obstacles in a drive path of the robot100. For example, now referring toFIG. 1B, which shows a bottom view of the robot100, as the wheel modules120a,120bpropel the robot100across the floor surface during a cleaning routine, the robot100may respond to events (e.g. collision with obstacles, walls) detected by the bumper130by controlling the wheel modules120a,120bto maneuver the robot100in response to the event (e.g., away from an obstacle).

Still referring toFIG. 1B, the bottom surface of the forward portion112of the robot100further includes a cleaning head180, a side brush140, wheel modules120a-b, a caster wheel126, clearance regulators128a-b, and cliff sensors530b. The cleaning head180, disposed on the forward portion112, receives a front roller310awhich rotates about an axis XAand a rear roller310bwhich rotates about an axis XB. Both axes XAand XBare substantially parallel to the axis X. Referring briefly toFIG. 2, the front roller310aand rear roller310brotate in opposite directions. More particularly, the rear roller310brotates in a counterclockwise sense CC, and the front roller310arotates in a clockwise sense C. Referring back toFIG. 1B, the rollers310a-bare releasably attached to the cleaning head180. The robot body110includes the side brush140disposed on the bottom forward portion112of the robot body110. The side brush140axis ZCis offset along the axes X and Y of the robot such that it sits on a lateral side of the forward portion112of the body110. The side brush140, in use, rotates and sweeps an area directly beneath one of the cliff sensors530b. The front roller310aand the rear roller310bcooperate with the side brush140to ingest debris, a process that will be discussed in more detail later. The side brush axis ZCis disposed forward of both the front roller axis XAand the rear roller axis XB.

Wheel modules120a,120bare substantially opposed along the transverse axis X and include respective drive motors122a,122bdriving respective wheels124a,124b. Forward drive of the wheel modules120a-bgenerally induces a motion of the robot100in the forward direction F, while back drive of the wheel modules120generally produces a motion of the robot100in the rearward direction A. The drive motors122a-bare releasably connected to the body110(e.g., via fasteners or tool-less connections) with the drive motors122a-bpositioned substantially over the respective wheels124a-b. The wheel modules120a-bare releasably attached to the body110and forced into engagement with the floor surface by respective springs125(shown inFIG. 2). The spring biasing, which will be shown and described later, allows the drive wheels124a-bto maintain contact and traction with the floor surface while cleaning elements (e.g. the rollers310a-b) of the robot100contact the floor surface as well.

The robot100further includes a caster wheel126disposed to support a rearward portion114of the robot body110. The caster wheel126swivels and is vertically spring-loaded to bias the caster wheel126to maintain contact with the floor surface. The caster wheel126rides on a hard stop while the robot100is mobile. A sensor in the caster wheel126detects if the robot100is no longer in contact with a floor surface (e.g. when the robot100backs up off a stair allowing the vertically spring-loaded swivel caster126to drop). The caster wheel126additionally keeps the rearward portion114of the robot body110off the floor surface and prevents the robot100from scraping the floor surface as it traverses the floor or as the robot100climbs obstacles. The spring biasing of the caster wheel126allows for a tolerance in the location of the center of gravity CG (shown inFIG. 2) of the robot100to maintain contact between the rollers310a-band the floor10. The robot100weighs between about 10 and 60 N empty. The robot100has most of its weight over the drive wheels124a-bto ensure good traction and mobility on surfaces. The caster126disposed on the rearward portion114of the robot body110can support between about 0-25% of the robot's weight.

The clearance regulators128a-b, rotatably supported by the robot body110adjacent to and forward of the drive wheels124a-b, are rollers that maintain a minimum clearance height (e.g., at least 2 mm) between the bottom surface of the body110and the floor surface. The clearance regulators128a-bsupport between about 0-25% of the robot's weight and ensure the forward portion112of the robot100does not sit on the ground when the robot100accelerates.

The robot100includes multiple cliff sensors530b-flocated near the forward and rear edges of the robot body110. Cliff sensors530c,530d, and530eare located on the forward portion112near the front surface103of the robot and cliff sensors530band530fare located on a rearward portion114. Each cliff sensor is disposed near one of the side surfaces so that the robot100can detect an incoming drop or cliff from either side of its body110. Each cliff sensor530b-femits radiation, e.g. infrared light, and detects a reflection of the radiation to determine the distance from the cliff sensor530b-fto the surface below the cliff sensor530b-f. A distance larger than the expected clearance between the floor and the cliff sensor530b-f, e.g. greater than 2 mm, indicates that the cliff sensor530b-fhas detected a cliff-like feature in the floor topography.

The cliff sensors530c,530d, and530elocated on the forward portion112of the robot are positioned to detect an incoming drop or cliff from either side of its body110as the robot moves in the forward direction F or as the robot turns. Thus, the cliff sensors530c,530d, and530eare positioned near the front right and front left corners (e.g., near the rounded surfaces107a-bconnect the front surface103to the side surfaces104a-b). Cliff sensor530eis positioned within about 1-5 mm of the rounded surface107b. Due to the location of the side brush at the corner of the robot, a cliff sensor cannot be placed at the same location on the opposite side of the robot near rounded surface107a. In order to still capture potential cliffs near the front (e.g., when the robot100is moving in the forward direction F) or the side (e.g., when the robot is turning), the robot includes a pair of cliff sensors positioned near the corner adjacent to the side brush140. A first cliff sensor530dis located along the front edge103of the robot and a second cliff sensor530cis located along the right side of the robot. Cliff sensors530cand530dare each positioned between least 10 mm and 40 mm from the corner of the robot100(e.g., rounded surface107a). The cliff sensors530cand530dare positioned near the side brush140such that the side brush140, in use, rotates and sweeps an area directly beneath cliff sensors530cand530d.

FIG. 1Cshows a perspective view of the robot100with a removable top cover105removed. ReferringFIG. 1C, the robot body110supports a power source102(e.g., a battery) for powering any electrical components of the robot100, and a vacuum module162for generating vacuum airflow to deposit debris into a dust bin (not shown). Referring briefly toFIG. 2, the location of a plenum182and the dust bin202are generally shown. The plenum182is a chamber above the rollers310in the cleaning head180, and the dust bin202sits in the rearward portion114of the robot. A conduit (not shown) connects the plenum182with the dust bin202. The vacuum module162includes an impeller (not shown) driven by a motor to produce the airflow from the plenum182into the dust bin202. Referring back toFIG. 1C, a handle106can be used to release the removable top cover to provide access to the dust bin. Releasing the removable top cover also allows access to a release mechanism for the cleaning head180, which is releasably connected to the robot body110. A user can remove the dust bin202and/or the cleaning head180to clean any accumulated dirt or debris. Rather than requiring significant disassembly of the robot100for cleaning, a user can remove the cleaning head180(e.g., by releasing tool-less connectors or fasteners) and empty the dust bin202by grabbing and pulling the handle106. The robot100further supports a robot controller151, which will be described in more detail later. Generally, the controller151operates electromechanical components of the robot100, such as the user interface138, the wheel modules120a-b, and the sensors530(shown inFIGS. 1A-B).

The vacuum module, dust bin, and cleaning head disclosed and illustrated herein may include, for example, vacuum systems, dust bins, and cleaning heads as disclosed in U.S. patent application Ser. No. 13/460,261, filed Apr. 30, 2012, titled “Robotic Vacuum,” the disclosure of which is incorporated by reference herein in its entirety.

FIG. 2, a simplified schematic side view of the robot100, depicts an example of a drive wheel suspension system described above. Although only the wheel module120ais schematically shown, it should be understood a similar suspension system is used for wheel module120b. The wheel modules120aare pinned to the robot body110and receive spring biasing, for example, between about 5 and 25 Newtons, that biases the drive wheel124adownward and away from the robot body110. Referring toFIG. 2, the drive wheel124ais supported by a drive wheel suspension arm123. The drive wheel suspension arm123is a bracket having a pivot point123a, a wheel pivot point123b, and spring anchor point123cspaced from the pivot point123aand the wheel pivot123b. The pivot point123ais pinned to the robot body110, and the wheel pivot point123brotatably supports the drive wheel124a. A drive wheel suspension spring125attached to a third end123bbiases the drive wheel124atoward the floor surface10. The spring125generates a force at the spring anchor123b, causing the suspension arm123to rotate about the pivot point123ato move the drive wheel124atoward the floor surface10. For example, the drive wheel124acan receive a downward bias of about 10 Newtons when moved to a deployed position and about 20 Newtons when moved to a retracted position into the robot body110.

The center of gravity CG of the robot100is located forward of the drive axis (0-35%) to help maintain the forward portion112of the body110downward, causing engagement of the rollers310a-bwith the floor. For example, the center of gravity placement allows the robot body110to pivot forwards about the drive wheels124a,124b.

FIG. 3depicts the structure of the side brush140. The side brush140agitates debris on the floor surface, moving the debris into the forward cleaning path of the vacuum module162(shown inFIG. 1C). The side brush140extends beyond the robot body110(e.g. extends beyond, referring briefly toFIG. 1A, the side surface104and the front surface103of the robot body110) allowing the side brush140to agitate debris in hard to reach areas such as corners and around furniture so that the rollers can ingest the debris. The side brush140rotates about an axis ZCthrough which a side brush axle (not shown) spans. The side brush140further includes struts150that extend from near the free end of the axle and bristle tufts160attached to the free ends of each strut. The bristles160are fibrous and can be made of synthetic or natural fibers, such as nylon or animal hair. While the robot body110is on the floor surface10, the axis ZCis oriented such that it forms a non-perpendicular angle with the plane that defines the floor surface10and a non-perpendicular angle with the bottom surface of the robot. The angle formed with the bottom surface of the robot is less than 90 degrees. The axle145attaches directly to a motor disposed in the robot body110. The struts150are evenly spaced about the axis ZC, are generally axisymmetric about the axis ZC, and each extends about 1 to 2 inches from the axis ZC. The struts150are made of a flexible material, such as an elastomer, so that they deform when they make contact with hard surfaces and obstacles. As shown, the three flexible struts150A-C are spaced 60 degrees from one another. The bristle tufts160have substantially the same length and coverage. The bristle tufts160, arranged in a circle defined by the extension of the struts150from the axle145, cover between 10% and 30% of the total perimeter of the circle.

FIGS. 4A, 4B, and 4Cpertain to the structure of the rollers310a-bshown inFIG. 1B.FIGS. 4A and 4Cillustrate exemplary facing rollers310a-bwith spaced chevron vanes360. Roller310aand roller310bdiffer in length but are structurally similar. The length of the rear roller310ais about 7 inches, and the length of the front roller is about 6 inches. Each roller310a-bincludes flanges1840and1850of an axle330and a foam core142supporting a tube350. The tube350forms the outer surface of each roller and is of a high-friction material such as an elastomer, so as to better grip incoming debris and to allow for deformation. For example, the tube350can be manufactured from thermoplastic polyurethane (TPU). In one implementation, the wall of the tube350has a thickness of about 1 mm, an inner diameter of about 23 mm, and an outer diameter of about 25 mm. The vanes360of the elastomeric polymer tube350are raised features of the outer surface of the tube350. The outer diameter of the outside circumference swept by the tips of the vanes360is about 30 mm.

Still referring toFIGS. 4A and 4C, the rollers310face each other such that the chevron-shaped vanes360on the tube350are mirror images. Each chevron-shaped vane of the illustrated rollers include a central point365and two sides or legs367extending downwardly therefrom on the front roller310aand upwardly therefrom on the rear roller310b. The two legs of the V-shaped chevron are at an angle of 7°. A chevron shape of the vanes360draws hair and debris away from the sides of the rollers and toward a center of the rollers to further prevent hair and debris from migrating toward the roller ends where they can interfere with operation of the robotic vacuum. The vanes360are integrally formed with the tube350and define V-shaped chevrons extending from one end of the tube350to the other end. The chevron vanes360are equidistantly spaced around the circumference of the tube350. The vanes360are aligned such that the ends of one chevron are coplanar with the central point365of an adjacent chevron so as to provide constant contact between the chevron vanes360and a contact surface with which the compressible roller310engages. Such uninterrupted contact eliminates noise otherwise created by varying between contact and no contact conditions. The chevron vanes360extend from the outer surface of the tube350at an angle α of about, for example, 45° relative to a radial axis of the roller310and inclined toward the direction of rotation.

As noted above, the rollers310face each other such that the chevron-shaped vanes360on the tube350are mirror images. In the example ofFIG. 4A, the chevron-shaped vanes of the longer roller (e.g., roller310b) are symmetrical about the central point365such that the length of the legs367extending to the right from the central point365have substantially the same length as the legs367extending to the left from the central point365. In order for the shorter roller (e.g., the front roller310a) to form a mirror image of the chevron-shape, the roller310ais not symmetrical about the central point365. Rather, the legs367extending to the right from the central point365have a different length than the legs367extending to the left from the central point365. The legs367of roller310aextending toward the side brush140are shorter than the legs367extending toward the side of the robot310without the side brush. In the example ofFIG. 4C, the chevron-shaped vanes of the shorter roller (e.g., roller310a) are symmetrical about the central point365such that the length of the legs367extending to the right from the central point365have substantially the same length as the legs367extending to the left from the central point365. In order for the longer roller (e.g., the roller310b) to form a mirror image of the chevron-shape, the roller310bis not symmetrical about the central point365. Rather, the legs367extending to the right from the central point365have a different length than the legs367extending to the left from the central point365. The legs367of roller310bextending toward the side brush140are longer than the legs367extending toward the side of the robot310without the side brush.

FIG. 4Billustrates a side perspective exploded view of a roller, such as roller310aofFIG. 4A. The axle330is shown, along with the flanges1840and1850of its driven end. The axle insert1930and flange1934of the non-driven end are also shown, along with the shroud730bof the non-driven end. Two foam inserts140a-bfit into the tube350to make up the collapsible, resilient foam core140for the tube350. The foam core140is resilient such that when the foam core140experiences a force that causes a deformation, upon removal of the force, the foam core140rebounds to its undeformed state. As shown, the tube350forms a sheath that encompasses the foam core140. Because the chevron vanes360extend from the outer surface of the tube350(e.g, by a height at least 10% of the diameter of the resilient tubular roller), they further prevent cord like elements from directly wrapping around the outer surface of the tube350. The vanes360therefore prevent hair or other string like debris from wrapping tightly around the foam inserts140of the roller310and reducing efficacy of cleaning.

The cleaning system includes a collection volume disposed on the robot body (e.g., the bin), a plenum arranged over the first and second roller brushes, and a conduit in pneumatic communication with the plenum and the collection volume. In some examples, the cleaning head180defines a recess having an L-shape for receiving the different length roller brushes310aand310b. The recess allows the rollers310aand310bto be in contact with a floor surface10for cleaning.

Referring toFIGS. 5A-B, the cleaning head180includes a plenum730a,730barranged over the rollers310aand310b. A conduit or ducting731a,731bprovides pneumatic communication between the plenum730a,730band the collection volume. The plenum730a,730bcooperates with the rollers310a-bto allow the vacuum module162to focus air flow through an air gap G of 1 mm or less. The conduit or ducting731a,731bis aligned with the small gap G exists between rollers310aand310bsuch that the center of the conduit or ducting731a,731blies directly above the gap G. The plenum730a,730bcan be formed of a unitary piece of molded plastic. Additionally, the shape of the plenum730a,730bcan be configured to provide minimal spacing (e.g., 1 mm or less) between the edge of the rollers and the surface of the plenum730a,730bto concentrate the airflow between the rollers.

The shape of the conduit or ducting731a,731bthat provides the pneumatic communication between the plenum730a,730band the collection volume can vary based on the desired airflow characteristics. In one example, as shown inFIG. 5A, the conduit or ducting731aextends along the length of the shorter of the two rollers310a. In this example, the conduit or ducting731adoes not extend along the portion of the longer roller310badjacent to the side brush140. By including the conduit or ducting731aonly in the region where the two rollers310aand310bare opposing one another, the airflow is concentrated between the rollers. While there is not a conduit adjacent to the additional portion of the longer roller310b(e.g., the portion adjacent to the side brush), debris collected by the longer roller310bin this region is directed toward the conduit or ducting731aby the chevron shape of the roller and a sloped portion of the shroud. Thus, the entire length of the longer roller aids in the collection of debris even in the absence of a conduit or ducting731adirectly above the roller. In another example, as shown inFIG. 5B, the conduit or ducting731bextends along the length of both the shorter rollers310aand the longer roller310b. In this example, the conduit or ducting731bhas a different width in the area between the two rollers310aand310bthan in the area adjacent to the additional portion of the longer roller310b(e.g., the portion adjacent to the side brush). The smaller opening of the portion of the conduit or ducting731bhelps to prevent air loss. By including the conduit or ducting731balong the entire length of both of the rollers, airflow can aid in debris collection along the entire length of the rollers.

FIG. 5Cis a cross sectional view of an exemplary driven end of an embodiment of a cleaning head roller310. The drivetrain, which will be described in more detail later, includes the rear roller gearbox450aand the front roller gearbox450b. The drivetrain is shown in the gearbox housing1810, along with a roller drive shaft1820and two bushings1822,1824. The roller drive shaft1820can have, for example, a square cross section or a hexagonal cross section as would be appreciate by those skilled in the art. A shroud730ais shown to extend from within the roller tube350to contact the gearbox housing1810and the bearing1824and can prevent hair and debris from reaching the gear1800. The axle330of the roller engages the roller drive shaft1820. In the illustrated embodiment, the area of the axle330surrounding the drive shaft1800includes a larger flange or guard1840and a smaller flange or guard1850spaced outwardly therefrom. The flanges/guards1840,1850cooperate with the shroud1830to prevent hair and other debris from migrating toward the gear1800. An exemplary tube overlap region1860is shown, where the tube350overlaps the shroud730a. The flanges and overlapping portions of the driven end shown inFIG. 5Ccan create a labyrinth-type seal to prevent movement of hair and debris toward the gear. In certain embodiments, hair and debris that manages to enter the roller despite the shroud overlap region1860can gather within a hair well or hollow pocket1870that can collect hair and debris in a manner that substantially prevents the hair and debris from interfering with operation of the cleaning head. Another hair well or hollow pocket can be defined by the larger flange1840and the shroud730a. The axle and a surrounding collapsible core preferably extend from a hair well on this driven end of the roller to a hair well or other shroud-type structure on the other non-driven end of the roller.

FIG. 5Dis a cross sectional view of an exemplary non-driven end of an embodiment of a roller310. A pin1900and bushing1910of the non-driven end of the roller are shown seated in the cleaning head lower housing390. A shroud extends from the bushing housing1920into the roller tube350, for example with legs1922, to surround the pin1900and bushing1910, as well as an axle insert1930having a smaller flange or guard1932and a larger flange or guard1934, the larger flange1934extending outwardly to almost contact an inner surface of the shroud1920. An exemplary tube overlap region1960is shown, where the tube350overlaps the shroud730b. The flanges/guards and overlapping portions of the drive end shown inFIG. 7Dcreate a labyrinth-type seal to prevent movement of hair and debris toward the gear. The shroud is preferably shaped to prevent entry of hair into an interior of the roller and migration of hair to an area of the pin. Hair and debris that manages to enter the roller despite the shroud overlap region1960gathers within a hair well or hollow pocket1970that can collect hair and debris in a manner that substantially prevents the hair and debris from interfering with operation of the cleaning head. Another hair well or hollow pocket is defined by the larger flange1934and the shroud730b.

Referring toFIG. 6A-Billustrate front and bottom perspectives, respectively, of an exemplary drivetrain600for driving the side brush140, the rear roller310b, and the front roller310asuch that the rollers310a-bare rotating counter to another. A motor620can directly drive the side brush140. The gear ratio for the gear train from the motor620to the axle driving the rear roller310bis the same as the gear ratio for the gear train from the motor620to the axle driving the front roller310a, which is about 1:10 to 1:30 (e.g., between 1:10 and 1:15, between 1:15 and 1:20, between 1:20 and 1:25; between 1:25 and 1:30). In one particular example, the main brush spins at between 1200-1330 RPM and the corner brush is running between 50-100 RPM. From the motor shaft625, the drivetrain600includes gears such that the motor620can drive both the rear roller310band front roller310a. Side brush bevel gear630can drive a rear roller bevel gear640band a front roller bevel gear640a. The mating angles between the side brush bevel gear630and rear roller bevel gear640bcan be 90 degrees or slightly offset from 90 degrees. Likewise, the mating angle between the side brush bevel gear630and front roller bevel gear640acan also be 90 degrees or slightly offset from 90 degrees. The front roller bevel gear640acan be coupled to the drive gear655acoupled to a front roller axle660a. The rear roller bevel gear640bcan be coupled to transfer gear650b,650c, which drives a drive gear655bcoupled to a rear roller axle660b. The configuration shown inFIG. 6A-Ballows a counterclockwise rotation of the motor from the perspective ofFIG. 6Bto cause the portions closer to the floor of the rear and front rollers310a-310bto rotate towards the gap G between the rollers.

Referring toFIG. 7, to achieve reliable and robust autonomous movement, the robot100includes a robot controller151that operates cleaning system170, a sensor system500, a drive system120, and a navigation system600. The cleaning system170is configured to ingest debris with use of the rollers310, the side brush140, and the vacuum module162.

The sensor system500having several different types of sensors530which can be used in conjunction with one another to create a perception of the robot's environment sufficient to allow the robot100to make intelligent decisions about actions to take in that environment. The sensor system500includes obstacle detection obstacle avoidance (ODOA) sensors, communication sensors, navigation sensors, contact sensors, a laser scanner, and an imaging sonar etc. Referring briefly toFIGS. 1A-B, the sensor system500further includes ranging sonar sensors530a, proximity cliff sensors530b, clearance sensors operable with the clearance regulators128a-b, contact sensors operable with the caster wheel126, and a bumper sensor system400that detects when the bumper130encounters an obstacle. Additionally or alternatively, the sensor system530may include, but not limited to, proximity sensors, sonar, radar, LIDAR (Light Detection And Ranging, which can entail optical remote sensing that measures properties of scattered light to find range and/or other information of a distant target), etc., infrared cliff sensors, contact sensors, a camera (e.g., volumetric point cloud imaging, three-dimensional (3D) imaging or depth map sensors, visible light camera and/or infrared camera), etc.

The drive system120, which includes the wheel modules120a-b, can maneuver the robot100across the floor surface based on a drive command having x, y, and θ components (shown inFIG. 1A). The controller151operates a navigation system600configured to maneuver the robot100in a pseudo-random pattern across the floor surface. The navigation system600is a behavior based system stored and/or executed on the robot controller151. The navigation system600communicates with the sensor system500to determine and issue drive commands to the drive system120.

The controller151(executing a control system) is configured to cause the robot to execute behaviors, such as maneuvering in a wall following manner, a floor sweeping manner, or changing its direction of travel when an obstacle is detected by, for example, the bumper sensor system400. The robot controller151can be responsive to one or more sensors530(e.g., bump, proximity, wall, stasis, and/or cliff sensors) of the sensor system500disposed about the robot100, as described earlier. The controller151can redirect the wheel modules120a,120bin response to signals received from the sensors530, causing the robot100to avoid obstacles and clutter while treating the floor surface10. If the robot100becomes stuck or entangled during use, the robot controller151may direct the wheel modules120a,120bthrough a series of escape behaviors so that the robot100can escape and resume normal cleaning operations.

The robot controller151can maneuver the robot100in any direction across the floor surface by independently controlling the rotational speed and direction of each wheel module120a,120b. For example, the robot controller151can maneuver the robot100in the forward F, rearward A, right R, and left L directions. As the robot100moves substantially along the fore-aft axis Y, the robot100can make repeated alternating right and left turns such that the robot100rotates back and forth around the center vertical axis Z (hereinafter referred to as a wiggle motion). Moreover, the wiggle motion can be used by the robot controller151to detect robot stasis. Additionally or alternatively, the robot controller151can maneuver the robot100to rotate substantially in place such that the robot100can maneuver away from an obstacle, for example. The robot controller151can direct the robot100over a substantially random (e.g., pseudo-random) path while traversing the floor surface.

FIG. 8shows a simplified view of the bottom surface of the robot100with a body width W and a forward edge width WF. The body width W is defined by the widest portion of the robot100as measured along the transverse axis X. The forward edge width WFrefers to the width of the portion of the forward surface parallel to the transverse axis X. As the rollers310a-brotate, the outer surfaces of the rollers310a-bthat face the floor cooperate with one another to guide debris into the dust bin102. A spacing distance DS, measured along the Y-axis, between the longitudinal axes of rotation XA, XBis greater than or equal to half of the sum of the diameters of the rollers310a-b. Thus, a small gap G exists between rollers310aand310b. A front surface distance DF, also measured along the Y-axis, defines the distance between the front longitudinal axis of rotation XAand the front surface103, which is less than or equal to twice the diameter of the front roller310a. In some examples, the front edge of the front roller310ais less than about 2 cm from the front edge103of the robot (e.g., less than about 2 cm, less than about 1 cm, less than about 0.5 cm). The rear roller310bis longer than the front roller310a. The longer rear roller310bincludes two ends311a-b, and the shorter front roller310aincludes two ends312a-b. The distance between the two ends311aand311bdefines the rear roller cleaning width WR1, and the distance between the two ends312aand312bdefines the front roller cleaning width WR2. The width of the wider of the two rollers310a-b, i.e. the rear roller310a, defines the overall roller cleaning width WR. The roller cleaning width WRindicates the span of the robot100that, as the robot100is driven forward or backward, will be capable of retrieving and ingesting debris with the mechanical motion of the rollers without the aid of the side brush. The roller cleaning width WRis at least about 75% of the width W of the forward portion112of the robot100(e.g., at least about 75%, at least about 80%, at least about 90%, at least about 95%). In some examples, a ratio of the front roller310acleaning width WR1to the rear roller310bcleaning width WR2is between about 1:2 and 9:10 (e.g., between about 1:2 and 9:10; between about 6:10 and 9:10; between about 7:10 and 9:10; about 4:5; about 9:10). In some examples, the rear roller310bcleaning width WR2can be at least about 0.5 inches (e.g., at least about 0.5 inches; at least about 0.75 inches; at least about 1 inch; at least about 1.5 inches; at least about 2 inches) greater than the front roller310acleaning width WR1.

As described earlier, air can be pulled through the air gap G between the front roller310aand the rear roller310bby, for example, by an impeller housed within or the vacuum module162(shown inFIG. 1C). The impeller can pull air into the cleaning head from the environment below the cleaning head, and the resulting vacuum suction can assist the rollers310in raising dirt and debris from the environment below the rollers310through the air gap G between the front roller310aand the rear roller310binto the dust bin202(shown in FIG.1C) of the robotic vacuum. Ends311a-bhave lengths of LR2and ends312a-bhave lengths of LR1, which are equal to the diameters of the rollers310aand310b, respectively. In the schematic as shown, the rollers310a-bcooperate to form a roller coverage region, defined by the sum of the projected area of each roller and the projected air gap area. The area ARof the roller coverage region can be determined by equation (1) below:
AR=LR1WR1+LR2WR2+GWR2(1)
In the implementation as shown, the roller coverage region area ARcovers between 10% and 50% of the total projected floor area ATof the robot100. In some examples, the roller coverage region area ARcovers between 25% and 35% of the total projected floor area AT of the robot100.

While the side brush140is rotating in a counterclockwise sense CC, any object on the floor surface in a substantially circular side brush cleaning region525contacts the side brush140. The struts and the bristles that protrude from the struts sweep the side brush cleaning region525as the axle rotates about the axis ZC. The side brush cleaning region525sweeps under the outer surfaces of the rollers310. The side brush140can generate the side brush cleaning region525that extends beyond the floor projection of the robot body110so that the robot can clean difficult-to-reach locations. The side brush cleaning region525can extend beyond both the front surface103of the robot body110and the lateral surface104aof the robot body110. In the example as shown, the roller end311aextends farther than the side brush axis ZCas measured along the X axis by about 0.5 cm to 5 cm. In some examples, the side brush includes bristles having a length that extends to the shorter of the rollers. In some additional examples, the side brush includes bristles having a length that extends past an intersection of a line extending from the generally straight side surface and a line extending generally parallel to the front generally flat surface. The struts and bristles may be positioned to contact the outer surfaces of the rollers310or may sweep under the rollers310without contacting them.

Methods of Use

FIG. 8further illustrates the sweeping of a large piece of debris D by the side brush140of the robot100as the robot100moves forward along a wall500.FIGS. 8-9together illustrate the process of facilitating the ingestion of the large piece of debris D. The robot100is in use and is being driven by its wheels to move in a forward direction F. The rollers310aand310bare rotating such that the roller surfaces closest to the ground are moving towards the gap between the rollers310a-b. The side brush140is being driven in a counterclockwise sense CC so that the portions of the side brush that extend past the robot body are rotating towards the center axis Y of the robot100. The robot100has encountered the wall500and has navigated into a position such that the side surface of the robot100is substantially parallel and in close proximity to the wall500.

The large piece of debris D initially sits against the wall500such that, as the robot100moves along the wall in the forward direction F, the large piece of debris D has a distance farther from the Y-axis than the rear roller end311a. Said another way, the roller cleaning width WRinitially does not encompass the piece of debris D. Still referring toFIG. 8, the robot moves along the wall500such that the side brush cleaning region525can reach the corner defined by the wall500and the floor. As shown, the side brush cleaning region525interferes with the wall, but the flexible structure of the side brush140allows the side brush140to deform in response to contact with the wall. When the robot reaches the large piece of debris D, the large piece of debris D enters the side brush cleaning region525and is agitated by the side brush140so that it takes a path P that generally follows the counterclockwise rotation of the side brush140. The side brush140forces the debris D to a position closer to the Y-axis than the rear roller end311a. As a result, the debris D is moved into a forward path of the roller cleaning width WRand can be ingested by the rollers. As the robot is driven forward, the large piece of debris D contacts the front roller310a. The front roller310awhich sits closer to the floor than the rear roller310b, directs the debris D towards the gap G between the rear and front rollers.

FIG. 9, a side cross section view of the rollers, now shows the debris D after it has been directed towards the gap G between the rollers. As shown, the front roller310arotates in a counterclockwise sense CC and the rear roller310brotates in a clockwise sense C. The front roller310arotates counterclockwise in this perspective such that the portion closer to the floor10rotates towards the gap G into the plenums730a-b. The rear roller310brotates towards the gap G as well and is thus rotating clockwise. As discussed, the shroud cooperates with the rollers such that the vacuum module creates a path of air suction555focused from the gap G. The path of air suction555begins near the gap G and is directed inward towards the dust bin of the robot, facilitating suction of dirt and debris into the dust bin. As shown inFIG. 9, the rollers310are collapsible to allow the debris D to pass through the gap G, despite the size of the debris being larger than the gap between the rollers. After the debris has passed through the rollers310, the rollers will retain (rebound to) their circular cross section due to their resiliency and the debris will move upward toward a dust bin conduit.

While the side brush axis is shown to be on the bottom surface of the robot, in some implementations, the side brush can extend from an inset portion of the bottom surface of the robot. The inset portion can raise and angle the side brush so that the side brush contacts the surface of the rollers as it rotates.

While sonar sensors are described herein as being arranged on the bumper, these sensors can be additionally or alternatively arranged at any of various different positions on the robot. For example, sonar sensors can be disposed on the side surfaces of the robot to allow the robot to predict incoming obstacles as it prepares to rotate.

While the wheel suspension bracket has been shown as a triangular piece of material that allows connections at three points to the spring, a wheel, and the robot body, in some implementations, the suspension bracket can be an L-shaped piece of material. The pivot points and anchor point can be located at substantially the same place as the pivot points and anchor point of the triangular version of the suspension bracket.

While an exemplary side brush has been shown and described, additional side brushes may be implemented to agitate debris from multiple directions of the robot. The number of struts may vary and the spacing may therefore also change.

While the side brush axis ZChas been described to form an angle less than 90 degrees with the bottom surface of the robot, in some implementations, the side brush axis can form an angle between 80 and 88 degrees with the bottom surface of the robot.

While the side brush axis ZChas been described to be disposed forward of the rear and front roller axes XB, XA, in some implementations, the side brush can be disposed rearward of the front roller axis and forward of the rear roller axis.

While the struts of the side brush have been described as flexible, in some implementations, the struts can be rigid. For example, struts that do not extend beyond the body of the robot do not impact nearby hard surfaces and obstacles as described earlier and thus can be rigid without risk of damage.

While the axle of the side brush has been described as a separate component from the motor shaft, in some implementations, the axle of the side brush could be the motor shaft. In some examples, now referring toFIG. 10, an annular structure152can support bristles160, which extend from the annular structure152at angle of about 25 to 35 degrees to the plane formed by the annular structure towards the floor, thus forming a circular brush to retrieve debris. In another example, the bristles can extend at an angle from one another such that they are crossed. As noted above, the cliff sensors are located under the reach of the side brush. As such, in order to allow the IR sensors to observe the flooring beneath the robot, the bristles can be grouped into bundles of bristles that extend to form a generally circular brush structure with gaps between the bundles of bristles. In general, as measured about the circumference of the circle formed by the bristles, between about 60% to about 90% (e.g., between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%) of the circumference can be occupied by the bristles leaving about 10% to about 40% (e.g., between about 10% to about 20%, between about 20% to about 30%, between about 30% to about 40%) open to observe the IR reflection by the cliff sensors. The bristle materials may include synthetic fibers, animal or plant fibers, or other fibrous material known in the art.

The drivetrain described above is one example of a means of driving the robot rollers and side brush with a single mechanical energy source. Other power delivery systems or configurations of the drivetrain above can be implemented to rotate the rollers and side brush. While the drivetrain is described having the gear configuration as shown inFIG. 5, it should be understood that the gear ratios of the drivetrain can be modified as needed for torque, velocity, and rotation direction specifications of any implementation of the robot. The drivetrain can be modified to have additional or fewer gears to attain a desired gear ratio desired rotation sense. The drivetrain may also include a belt, a chain, or another means known in the art to transmit force over longer distances through the drivetrain. In implementations where the axis of the side brush creates an acute angle with the floor, one of the mating (rear roller or front roller) bevel gears could mate with the side brush bevel gear at less than 90 degrees, and the other mating bevel gear could mate with the side brush bevel gear at greater than 90 degrees.

While the drivetrain is described to simultaneously drive both rollers and the side brush, in some implementations, separate drivetrains can drive each roller and the side brush. In other implementations, a drivetrain can drive one roller and the side brush, and the other roller can be undriven or be driven by a separate drivetrain.

The rotational velocity of the front roller and the rear roller can be different than the rotational velocity of the motor output, and can be different than the rotational velocity of the impeller. The rotational velocity of the impeller can be different than the rotational velocity of the motor. In use, the rotational velocity of the front and rear rollers, the motor, and the impeller can remain substantially constant.

While a foam core has been described to support the tube of the rollers, in other implementations, curvilinear spokes replace all or a portion of the foam supporting the tube. The curvilinear spokes can support the central portion of the roller, between the two foam inserts and can, for example, be integrally molded with the roller tube and chevron vane.

While the rollers are shown to include six chevron vanes in one implementations, in other implementations, the rollers may have more or fewer vanes. For example, with larger flexible vanes, each vane can contact the floor for a longer period of time. As a result, fewer vanes can be used to maintain the same amount of floor contact time.

While the vane angle α is described to be about 45° relative to a radial axis, in some implementations, the angle α of the chevron vanes can be between 30° and 60° to the radial axis. Angling the chevron vanes in the direction of rotation can reduce stress at the root of the vane, thereby reducing or eliminating the likelihood of vane tearing away from the resilient tubular member. The one or more chevron vanes contact debris on a cleaning surface and direct the debris in the direction of rotation of the compressible roller.

While the angle between the legs of the V of the V-shaped chevrons has been described as 7°, in other implementations, the legs of the V are at a 5° to 10° angle relative a linear path traced on the surface of the tubular member and extending from one end of the tube to the other end. By limiting the angle θ to less than 10° the compressible roller can be more easily manufactured by molding processes. Angles steeper than 10° can create failures in manufacturability for elastomers having a durometer harder than 80 shore A.

While the tube has been described as elastomeric, in some implementations, the tube is injection molded from a resilient material of a durometer between 60 and 80 shore A. A soft durometer material than this range can exhibit premature wear and catastrophic rupture and a resilient material of harder durometer can create substantial drag (i.e. resistance to rotation) and can result in fatigue and stress fracture.

The rollers shown in this example comprise concentric layers. While each roller is shown and described to be continuous, in some implementations, at least one of the rollers, such as the front roller or the rear roller, can comprise two or more separate longitudinal roller segments rotating about the same axis of rotation. The segments of a single roller can each have their own driving mechanism or be coupled so that a single drivetrain can actuate all the segments. In other implementations, the lengths and diameters related to the roller (e.g. of the tube, the vanes, etc.) may vary.

While the vanes are shown to span continuously from the outer ends of the rollers to the center of the rollers, in some implementations, the vanes can discontinuously converge via segments that are along the same line. As these raised segments are not attached to one another, they are more flexible than a continuous vane. Further, while the rollers have been described to be continuous structures that span from one side of the robot to the other side of the robot, in some implementations, the front or rear roller can be split into sections that rotate about the same axis. For example, the front roller may have two equally sized sections that rotate about an axis XA. A gap may be situated between the two sections.

While the length of the rear roller310bhas been described to be 7 inches and the length of the front roller310ahas been described to be 6 inches, in other implementations, the length of the rollers can be longer or shorter. For example, with a larger diameter side brush, the front roller can be, for example, half the length of the rear roller. The rear roller can be shorter as well with the larger diameter side brush.

In some implementations, the rollers are driven individually by corresponding brush motors or by one of the wheel drive motors or side brush motor. One roller may be driven independently from the other roller. The driven roller brush agitates debris on the floor surface, moving the debris into a suction path for evacuation to the collection volume. Additionally or alternatively, one of the two rollers can be driven while the other is not driven but still has a rotational degree of freedom about its longitudinal axis. The driven roller brush may move the agitated debris off the floor surface and into a dust bin adjacent the roller brush or into one of the ducting. The driven roller may rotate so that the resultant force on the floor pushes the robot forward.

Moreover, the rollers may rotate in the same or opposite directions about their respective longitudinal axis XA, XB. Preferably, the rollers counter-rotate such that both of their facing surfaces move upward during floor cleaning, to help to draw debris into the robot. In some examples, the robot includes first and second roller motors. The first roller motor can be coupled to the front roller and drives the front roller brush in a first direction. The second roller motor can be coupled to the rear roller and drives the rear roller in a second direction opposite the first direction. The first direction of rotation may be a forward rolling direction with respect to the forward drive direction.

In some implementations the side brush axis ZCforms a 10-20 degree angle with the axis Z. While the side brush cleaning region is shown and described to be substantially round, it should be understood that greater offsets of the axis ZCfrom the floor surface result in a more oblong shape for the side brush cleaning region.

While the roller coverage region area ARhas been described to occupy between 20% and 50% of the total projected area ATof the robot, in some implementations, the roller coverage region area can occupy a smaller or larger percent of the total projected area. For example, in cases where the side brush can sweep a larger area, the rollers can have a smaller width and still allow the robot to achieve a similar cleaning efficacy. Conversely, in cases where the side brush can sweep a smaller area, the rollers can have a larger width to achieve a similar cleaning efficacy.

While the path of air suction is shown to originate at the gap between the rollers, the path of air suction may extend to air substantially contacting the floor. The path of air flow may extend past the gap and towards the floor, further assisting the rollers in guiding the debris towards the dust bin.

In some implementations, the robot has at least one roller with bristles and/or beater flaps. The bristles are fibrous and can be made of synthetic or natural fibers, such as nylon or animal hair.FIG. 11Ashows a side view of an example cleaning head180where the front roller310ahas three sets of one longitudinal row315of bristles318and the rear roller310bhas three sets of two longitudinal rows325a-bof bristles320a-b. The longitudinal rows325a-bof a set are circumferentially spaced about the roller core140. Each bristle318,320a,320bhas one end attached to the core140and the other end unattached. The bristles318,320a,320bof the same row (e.g. rows315,325a,325b) all have substantially the same length.

Each bristle318,320a,320bhas a bristle offset O, defined as how far forward or behind the rotation axis XA, XBof the brush310the bristles318,320a,320bare mounted with respect to the intended direction C of brush310rotation. Bristles318,320a,320bmounted forward of the center axis XA, XBwill naturally be swept-back when contacting the floor10, thus resulting in reduced power consumption compared to configurations of bristles mounted behind the center axes. Bristles318,320a,320bmounted in front of the center axis XA, XBof the roller310also yield longer bristles318,320a,320bfor the same effective diameter, creating a roller310that is relatively less stiff. As a result, a current draw or power consumption while traversing and cleaning a carpeted floor surface can be significantly reduced compared to a rear offset bristle configuration. The bristles318,320a,320bhave an offset of, for example, between 0 and 3 mm behind the center axis XA, XBof the brush310.

For the rear roller310b, the first row325ahas bristles320aof diameter 0.009 inches, and the second row has bristles320bof diameter 0.005 inches. The first bristle row325a(the larger diameter bristle row) is relatively less stiff than the second bristle row325b(the smaller diameter bristle row) to impede filament winding about the roller core140(i.e., the shorter bristles are stiffer). As the robot100picks up hair from the surface10, the hair may not be directly transferred from the surface to the dust bin, but rather may require some time for the hair to migrate from the brush310and into the plenum182and then to the dust bin. Flexible bristles reduce entrapment of the hair on the rollers, causing more deposition of the hair into the dust bin.

Rollers310a,310bare spaced apart such that distal second ends of their respective bristles318,320,330are distanced by a gap of, for example, about 1-10 mm. As the plenum182accumulates debris, the brushes310a,310bscrape the debris off the plenum182, thus minimizing debris accumulation. The bristles320a-bare long enough to interfere with the plenum182keeping the inside of the plenum182clean and allowing for a longer reach into transitions and grout lines on the floor surface10. The bristles320a-bare also long enough to interfere with the bristles318.

Both brushes310a,310binclude vanes340arranged between and substantially parallel to the rows315of bristles318or dual-rows325of bristles320,330. Each vane340includes an elastomeric material with one end attached to the core140to the other end free. The vanes340prevent hair from wrapping about the roller core314. Additionally, the vanes340keep the hair towards the outer portion of the roller core314for easier removal and cleaning.

FIG. 11Bis perspective view of the rear roller310b. Referring toFIG. 11B, the vanes340define a chevron shape on the core140. The vanes340are shorter than the bristles318,320,330. The vanes340facilitate the removal of hair wrapped around the core140because the vanes340prevent the hair from deeply wrapping tightly around the roller core314. The vanes340increase the airflow past the rollers310a,310b, which in turn increases the deposition of hair and other debris into the dust bin202b. Since the hair is not deeply wrapped around the core140of the roller310, the vacuum can still pull the hair off the roller310. The first and second bristle rows325a,325bare separated circumferentially along the core140by a narrow gap. The rows325a,325balso define a chevron shape on the core140.

While the bristles of the first row were described to have diameter of 0.009 inches and the bristles of the second row were described to have a diameter of 0.005 inches, in some examples, the bristles of the first row have a bristle diameter of 0.003-0.010 inches and are adjacent and parallel to a bristles of the second row having a bristle diameter of between 0.001-0.007 inches.

While the bristles were described to have substantially the same length, bristles of one row may be longer than bristles of another row. For example, in the case of a roller with three sets of two longitudinal rows of bristles, the row farther offset from the roller axis of rotation can be shorter than the other row. The cascaded bristle length can ensure that that both rows of bristles have equal contact with the ground surface. In some examples, the bristle length of the farther offset row of bristles is less than 90% of the bristle length of the second row. In some implementations, the farther offset row may further be made of a different material composition than the bristles of other row. The bristle composition of the first row can be stiffer than the bristle composition of the second row. A combination of soft and stiff bristles, where the soft bristles longer than the stiff bristles, can allow the hair to be trapped in the longer soft bristles and therefore migrate to the collection bin faster. Additionally, the combination of denser and/or stiffer bristles enables retrieval of debris, particularly hair, from a myriad of surface types. The first row of bristles can be effective at picking up debris from hard flooring and hard carpet. The soft bristles can be better at being compliant and releasing collected hair into the plenum. As the cleaning system suctions debris from the floor surface, dirt and debris can adhere to the plenum of the cleaning head.

While the number of longitudinal rows are shown to be one or two, in other implementations, there can be three or more longitudinal rows of bristles for a set. The cleaning head may further include other elements to assist with cleaning. For example, the cleaning head can include a wire bail to prevent larger objects (e.g., wires, cords, and clothing) from wrapping around the brushes. The wire bails may be located vertically or horizontally, or may include a combination of both vertical and horizontal arrangement.

The robot may further include at least one brush bar arranged parallel to and engaging the bristles of one of the rollers. The brush bars can interfere with the rotation of the engaged rollers to strip fibers or filaments from the engaged bristles. As the rollers rotate to clean a floor surface, the bristles can make contact with the brush bar. The brush bars agitate debris (e.g., hair) on the ends of the brushes and swipes them into the vacuum airflow for deposition into the dust bin. The roller allows the robot to increase its collection of debris specifically hair in the dust bin, and reduce hair entangling on the brushes.

While the alternative implementation for the rollers described above includes bristles on both rollers, in some implementations, one roller can be an elastomeric roller of the exemplary implementation of this disclosure, and the other roller can be a brush roller as described above. Each roller in such a combination can be designed to pick up specific types of debris so that the robot can generally ingest many kinds of debris.