Mobile cleaning robot suspension system

Abstract

A mobile cleaning robot movable within an environment may include a body, a drive arm, a reservoir, a biasing element, and a link. The drive arm may be coupled to the body and movable relative to the body. The drive arm may support a drive wheel. The reservoir may be coupled to the body and configured to convey a fluid therein. The biasing element may be coupled to the drive arm to bias the drive wheel toward a floor surface. The link may be pivotally coupled to the body and coupled to the biasing element. The link may be engageable with the reservoir to adjust the biasing element based on the amount of fluid in the reservoir.

Description

[Technical Field]

[0001] Priority Application This application is a continuation of and claims priority to U.S. Patent Application No. 17 / 878,953, filed August 2, 2022, the contents of which are incorporated by reference herein in their entirety. [Background technology]

[0002] Mobile robots include mobile cleaning robots that can perform cleaning tasks in environments such as homes. The mobile cleaning robots can run across floor surfaces and avoid obstacles while spraying fluid or applying fluid through pads, so that the fluid can be absorbed by the pads as the robot traverses the environment to effectively perform a mopping action in the environment. Summary of the Invention [Problem to be solved by the invention]

[0003] Mobile cleaning robots can navigate autonomously through an environment to perform cleaning tasks, often moving over and around obstacles. Mobile cleaning robots are equipped with suspension systems to provide sufficient downward wheel force to overcome obstacles and provide effective cleaning on various surfaces. Because obstacles can vary in shape and size, and floor types can also vary, the required downward wheel force can change during the robot's operation. Many robots use tension or compression springs directly connected to the wheel arms and are equipped with suspension systems that can effectively transmit downward force, but in mopping robots, the mass or weight of the robot can change throughout a mission, changing the transmitted downward force that is desirable for optimal cleaning performance. [Means for solving the problem]

[0004] This disclosure describes devices and methods that can help address this problem, such as by providing a suspension system including a container for storing cleaning fluid connected to one or more links and a biasing element connected to the drive arm of the wheel. As the fluid height in the tank changes, the weight or mass of the tank (and robot) changes, affecting the desired downward force for optimal cleaning performance and mobility. The tank can be movable when the volume of fluid changes, moving a link that can further move a tension spring to adjust the downward force provided to the drive arm and drive wheel (or wheels) of the robot. In this manner, the robot can be equipped with a passive suspension adjustment system to help adjust the downward force delivered based on the amount of fluid (and mass of fluid) in the tank to improve cleaning performance and mobility, as the amount of fluid in the tank changes during a cleaning mission.

[0005] For example, a mobile cleaning robot movable within an environment may include a body, a drive arm, a reservoir, a biasing element, and a link. The drive arm may be coupled to the body and movable relative to the body. The drive arm may support a drive wheel. The reservoir may be coupled to the body and configured to convey a fluid therein. The biasing element may be coupled to the drive arm to bias the drive wheel toward a floor surface. The link may be pivotally coupled to the body and coupled to the biasing element. The link may be engageable with the reservoir to adjust the biasing element based on the amount of fluid in the reservoir.

[0006] In the drawings, which are not necessarily to scale, like numerals may represent like components in different figures. Like numerals with different subscripts may represent different instances of like components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in this document. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view of a mobile cleaning robot in an environment. [Figure 2A] FIG. 2 is a bottom view of the mobile cleaning robot. [Figure 2B] FIG. 1 is an isometric view of a mobile cleaning robot. [Figure 2C] FIG. 2 is a top view of the mobile cleaning robot. [Figure 3A] 2B is a cross-sectional view of the mobile cleaning robot across the support portion 3-3 of FIG. 2A in a first condition. [Figure 3B] 2B is a cross-sectional view of the mobile cleaning robot across the support portion 3-3 of FIG. 2A in a second condition. [Figure 4] FIG. 2 is a cross-sectional view of the mobile cleaning robot. [Figure 5] FIG. 1 is a schematic diagram of a mobile cleaning robot network. [Figure 6] FIG. 1 is a schematic diagram of a system. DETAILED DESCRIPTION OF THE INVENTION

[0008] Robot Overview FIG. 1 shows a plan view of a mobile cleaning robot 100 in an environment 40. The environment 40 may be a dwelling, such as a house or apartment building, and may include rooms 42a-42e. Obstacles, such as a bed 44, a table 46, and an island 48, may be located in the rooms 42 of the environment. Each of the rooms 42a-42e may have a floor surface 50a-50e, respectively. Some rooms, such as room 42d, may include a rug, such as rug 52. The floor surface 50 may be of one or more types, such as hardwood, ceramic, low-pile carpet, medium-pile carpet, long (or high) pile carpet, or stone.

[0009] The mobile cleaning robot 100 can be operated, such as by a user 60, to autonomously clean the environment 40 in a room-by-room manner. In some examples, the robot 100 can clean the floor surface 50a of one room, such as room 42a, before moving on to the next room, such as room 42d, to clean the surfaces of room 42d. Different rooms can have different types of floor surfaces. For example, room 42e (which can be a kitchen) can have a hard floor surface, such as wood or ceramic tile, while room 42a (which can be a bedroom) can have a carpeted surface, such as medium-pile carpet. Other rooms, such as room 42d (which can be a dining room), can include multiple surfaces, where rug 52 is positioned within room 42d. The robot 100 can be configured to navigate across various floor types through one or more components, such as a suspension system. The robot's suspension system enables the robot 100 to navigate over obstacles, such as thresholds between rooms, or over rugs, such as rug 52.

[0010] Also, during cleaning or navigating operations, the robot 100 can use data collected from various sensors (such as optical sensors) and calculations (such as odometry and obstacle detection) to develop a map of the environment 40. Once the map is created, the user 60 can define rooms or zones (such as room 42) within the map. The map can be presentable to the user 60 in a user interface, such as a mobile device, allowing the user 60 to, for example, direct or change cleaning preferences.

[0011] Also, during operation, the robot 100 can detect surface types within each of the rooms 42, which may be stored on the robot or other devices. The robot 100 can update the map (or data associated with the map), such as to include or configure the surface types of the floor surfaces 50a-50e of each room 42 of the environment. In some examples, the map can be updated to show different surface types, such as within each of the rooms 42.

[0012] Robot components Figure 2A shows a bottom view of the mobile cleaning robot 100. Figure 2B shows an isometric view of the mobile cleaning robot 100. Figure 2C shows a top view of the mobile cleaning robot 100. Figures 2A-2C are considered together below.

[0013] The cleaning robot 100 may be a mobile cleaning robot that can autonomously traverse the floor surface 50 while mopping dirt or debris 75 from different portions of the floor surface 50. As depicted in FIGS. 2A-2C , the robot 100 may include a body 102 that is movable across the floor surface 50. The body 102 may include a plurality of articulated structures to which the movable components of the cleaning robot 100 may be mounted. The articulated structures may include an outer housing 103 for covering the internal components of the cleaning robot 100, drive wheels 104 a and 104 b, a chassis to which a cleaning pad 106 is mounted, and a shock absorber 108 mounted to the outer housing.

[0014] 2A , the robot 100 may include a drive system including actuators 110a and 110b, such as motors, operable with the drive wheels 104a and 104b. The actuators 110a and 110b may be mounted to the body 102 and operably coupled to the drive wheels 104a and 104b, which are rotatably mounted to the body 102. The drive wheels 104a and 104b may support the body 102 above the floor surface 50. When driven, the actuators 110a and 110b may rotate the drive wheels 104a and 104b to move the robot 100 across the floor surface 50.

[0015] The controller (or processing unit) 112 can be located within the housing 103 and can be a programmable controller, such as a single- or multi-board computer, a direct digital controller (DDC), or a programmable logic controller (PLC). In other examples, the controller 112 can be any computing device, such as a portable computer, e.g., a smartphone, a tablet, a laptop, a desktop computer, or any other computing device that includes a processing unit and communications capabilities. The memory 114 can be one or more types of memory, such as volatile or non-volatile memory, read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, other storage devices, and other storage media. The memory 114 can be located within the housing 103 and can be coupled to and accessible by the controller 112.

[0016] 2B, the robot 100 may also include a nozzle or discharge port 116 configured to spray and eject the fluid f from the robot onto the floor surface 50. The nozzle or discharge port 116 may be coupled to a pump 118 positioned within the body 102 or housing 103. The nozzle or discharge port 116 may be coupled to the pump 118 via a pipe or piping. The robot 100 may also include a tank or container 120 configured to store the fluid f within the body 102 or housing 103 between cleaning missions, as shown in FIG. 2C. The pump 118 may be coupled to the tank 120 via a pipe or piping to connect the nozzle or discharge port 116 to the tank 120. The pump 118 may also be coupled to the controller 112.

[0017] The controller 112 can operate the actuators 110a and 110b to cause the robot 100 to navigate autonomously across the floor surface 50 during cleaning operations. The actuators 110a and 110b are operable to drive the robot 100 in forward drive and rearward directions and to turn the robot 100. The cleaning pad 106 can help support the front portion of the body 102 above the floor surface 50, while the drive wheels 104a and 104b support the middle and rear portions of the body 102 above the floor surface 50. The cleaning pad 106 can be removably mounted to the body 102 of the robot 100. In this manner, the cleaning pad 106 can be replaceable by a user, such as if it becomes soiled during a cleaning mission.

[0018] The control system may further include a sensor system 122 including one or more electrical or optical sensors. The sensor system may include one or more sensors for generating signals indicative of the current location of the robot 100, as described herein, and may include sensors for generating signals indicative of the location of the robot 100 as it progresses along the floor surface 50.

[0019] Cliff sensors 124 (shown in FIG. 2A ) may be positioned along a bottom portion of the housing 103. Each of the cliff sensors 124 may be an optical sensor that may be configured to detect the presence or absence of an object below it, such as the floor surface 50. The cliff sensors 124 may be coupled to the controller 112. The bumper 108 may be removably secured to the body 102 and may be movable relative to the body 102 while being mounted thereon. In some examples, the bumper 108 forms part of the body 102. Collision sensors 126 a and 126 b (collision sensors 126) may be coupled to the body 102 and may be engageable or configured to interact with the bumper 108. The bump sensor 126 may comprise a break beam sensor, a capacitive sensor, a switch, or other sensor capable of detecting contact between the robot 100, i.e., the bumper 108, and an object in the environment 40. The bump sensor 126 may be in communication with the controller 112.

[0020] The image capture device 128 may be a LIDAR sensor coupled to the body 102 and may extend through the bumper 108 of the robot 100, such as through an opening in the bumper 108. The image capture device 128 may be configured to generate signals based on images of the environment 40 of the robot 100 as the robot 100 moves about the floor surface 50. The image capture device 128 may send signals to the controller 112 for use in driving and cleaning routines. The image capture device 129 may be a camera coupled to the body 102 and may extend through the bumper 108 of the robot 100. The image capture device 129 may be a camera, such as a forward-facing camera, configured to generate signals based on images of the environment 40 of the robot 100 as the robot 100 moves about the floor surface 50. The image capture device 129 may send signals to the controller 112 for use in driving and cleaning routines.

[0021] The obstacle monitoring sensor 130 (shown in FIG. 2A ) can include an optical sensor facing outward from the bumper 108, which can be configured to detect the presence or absence of an object adjacent to the side of the body 102. The obstacle monitoring sensor 130 can emit a light beam horizontally, in a direction perpendicular (or nearly perpendicular) to the forward drive direction of the robot 100. The optical emitter can emit the light beam outward from the robot 100, e.g., horizontally outward, and the optical detector detects reflections of the light beam that reflect off objects near the robot 100. The robot 100 can determine the time of flight of the light beam, using, for example, the controller 112, thereby determining the distance between the optical detector and the object, and therefore the distance between the robot 100 and the object.

[0022] The robot 100 may also include one or more buttons 132 (or interfaces) that may include a user-operable interface configured to provide commands to the robot, such as to pause a mission, power on, power off, or return to a docking station.

[0023] As shown in Figure 2B, a lid 134 may be coupled to the body 102, such as over the tank 120. The lid 134 may be operable to open to access the tank 120, such as for inserting or removing the tank 120 or adding a fluid f (e.g., a cleaning fluid) to the tank 120. Figure 2B also shows that a link 136 may be coupled to one or more lateral sides of the tank 120. The link 136 may be part of a suspension system, as discussed in more detail below.

[0024] Robot movement In some example operations, the robot 100 may be propelled in a forward drive direction or a reverse drive direction. The robot 100 may also be propelled to turn in place or to turn while moving in a forward drive direction or a reverse drive direction.

[0025] When the controller 112 causes the robot 100 to perform a task, the controller 112 may operate the motors 110 to drive the drive wheels 104 and propel the robot 100 along the floor surface 50. The controller 112 may also operate the pump 118 to dispense a fluid f onto the floor surface 50. The controller 112 may execute software stored in the memory 114 to operate the various motors of the robot 100 and thereby cause the robot 100 to perform various running and cleaning behaviors.

[0026] Various sensors on the robot 100 may be used to assist the robot in navigating and cleaning within the environment 40. For example, the cliff sensor 124 may detect obstacles such as drop-offs and cliffs below the portion of the robot 100 where the cliff sensor 124 is located. The cliff sensor 124 may send a signal to the controller 112 so that the controller 112 can reorient the robot 100 based on the signal from the cliff sensor 124.

[0027] In some examples, bump sensor 126a can be used to detect movement of bumper 108 along the front-to-back axis of robot 100. Bump sensor 126b can also be used to detect movement of bumper 108 along one or more sides of robot 100. Bump sensor 126 can send a signal to controller 112 so that controller 112 can reorient robot 100 based on the signal from bump sensor 126.

[0028] The image capture device 128 may be configured to generate signals based on images of the environment 40 of the robot 100 as the robot 100 moves about the floor surface 50. The image capture device 128 may transmit such signals to the controller 112. In some examples, the obstacle monitoring sensors 130 may detect detectable objects, including obstacles such as furniture, walls, people, and other objects in the environment of the robot 100. In some implementations, the sensor system may include obstacle monitoring sensors along the sides, which may detect the presence or absence of objects adjacent to the sides. One or more of the obstacle monitoring sensors 130 may also serve as obstacle detection sensors, similar to the proximity sensors described herein. The image capture device 129 may be angled in an upward direction, for example, angled between 5 and 45 degrees from the floor surface 50 over which the robot 100 moves about. When angled upward, the image capture device 129 may capture images of the wall surfaces of the environment such that features corresponding to objects in the wall surfaces can be used for localization.

[0029] The robot 100 may also include sensors for tracking the distance traveled by the robot 100. For example, the sensor system may include encoders associated with the motors 110 for the drive wheels 104, which may track the distance traveled by the robot 100. In some implementations, the sensors may include optical sensors that face downward toward the floor surface. The optical sensors may be positioned to direct light through the bottom of the robot 100 toward the floor surface 50. The optical sensors may detect reflections of light and may detect the distance traveled by the robot 100 based on changes in floor features as the robot 100 travels along the floor surface 50.

[0030] The controller 112 can use data collected by sensors in the sensor system to control the traveling behavior of the robot 100 during a mission. For example, the controller 112 can use sensor data collected by obstacle detection sensors (cliff sensors 124, collision sensors 126, and image capture devices 128) of the robot 100 to enable the robot 100 to avoid obstacles in the environment of the robot 100 during a mission.

[0031] The sensor data can also be used by the controller 112 for simultaneous localization and mapping (SLAM) techniques, in which the controller 112 extracts features of the environment represented by the sensor data and builds a map of the floor surface 50 of the environment. The sensor data collected by the image capture device 128 can also be used for techniques such as vision-based SLAM (VSLAM), in which the controller 112 extracts visual features corresponding to objects in the environment 40 and builds a map using these visual features. As the controller 112 directs the robot 100 around the floor surface 50 during a mission, the controller 112 can use SLAM techniques to detect features represented in the collected sensor data and compare the features to previously stored features to determine the location of the robot 100 within the map. The map formed from the sensor data can indicate the locations of passable and impassable spaces within the environment. For example, the locations of obstacles can be indicated on the map as impassable spaces, and the locations of open floor spaces can be indicated on the map as passable spaces.

[0032] Sensor data collected by any of the sensors may be stored in memory 114. Other data generated for SLAM techniques, including cartography data forming a map, may also be stored in memory 114. This data generated during a mission may include persistent data generated during a mission that can be used during further missions. In addition to storing software for causing robot 100 to perform its actions, memory 114 may store data resulting from processing of sensor data for access by controller 112. For example, a map may be usable and updatable by controller 112 of robot 100 from one mission to another to navigate robot 100 around floor surface 50.

[0033] Persistent data, including a persistent map, helps enable the robot 100 to efficiently clean the floor surface 50. For example, the map can enable the controller 112 to direct the robot 100 to open floor spaces and avoid impassable spaces. The controller 112 can also use the map to optimize the path taken during a mission to help plan the robot 100's travel through the environment 40 for subsequent missions.

[0034] Suspension system example 3A shows a cross-sectional view of the mobile cleaning robot 300 across the indicator 3-3 of FIG. 2A in a first condition. FIG. 3A shows a cross-sectional view of the mobile cleaning robot 300 across the indicator 3-3 of FIG. 2A in a second condition. FIG. 3A and FIG. 3B are discussed together below. The mobile cleaning robot 300 can be similar to the robot 100 discussed above, and like numbers can represent like components.

[0035] The mobile cleaning robot 300 may include a body 302 and a suspension system 335 including a drive arm 338 coupled to the body at an arm pivot 339. The drive arm 338 may be movable or rotatable relative to the body 302 about the arm pivot 339. The drive arm 338 may also be coupled to the drive wheels 310, such as to support the drive wheels 310. The drive wheels 310 engage the floor surface 50 to help move the mobile cleaning robot 300 around in the environment 40. Optionally, the suspension system may include a four-bar linkage coupled to the body 302.

[0036] The mobile cleaning robot 300 may also include a container or tank 320 connectable to the body 302. For example, the tank 320 may be positionable or locatable within the body 302. The tank 320 may optionally be detachable from the body 302 of the mobile cleaning robot 300. The tank 320 may be configured to carry a fluid f therein, such as for dispensing by a sprayer or nozzle (e.g., nozzle 116), as discussed above. The tank 320 may be any container or tank configured to receive and hold a fluid therein. In other examples, the tank or tank 320 may be configured to receive dry debris.

[0037] Suspension system 335 may also include a biasing element 340 coupled to drive arm 338 and link 336. Biasing element 340 may be any biasing element, such as a tension spring, compression spring, spring bar, or torsion spring. Biasing element 340 may be coupled to a pivot 342 for coupling biasing element 340 to drive arm 338 to bias drive wheel 310 toward floor surface 50. Biasing element 340 may also be coupled to a pivot 344 for coupling biasing element 340 to link 336, such as to allow rotation of biasing element 340 relative to drive arm 338 and link 336.

[0038] The suspension system 335 may also include a link 336 that may be movably (e.g., pivotably, rotatably, or slidably) coupled to the body 302 at a pivot 346. The link 336 may include a protrusion 348, which may be a projection, a protrusion, a coupler, a slider, or other feature. The protrusion 348 may engage with a guide 350 on the tank 320 such that the protrusion 348 and the guide 350 may form a sliding linkage or a rotating mechanism so that movement of the tank causes movement of the link 336, as discussed in more detail below. Although only one link 336 is shown, the mobile cleaning robot 300 may include two (as shown in FIG. 2C ) or more links, such as three, four, five, six, seven, eight, nine, ten, etc. Link 336 may be engageable or engaged with tank 320, such as protrusion 348 and guide 350, to adjust biasing element 340 based on the amount of fluid f in tank 320. Link may be L-shaped to accommodate three connection points, as shown in Figures 3A and 3B, but may have other shapes in other examples, such as X-shaped, C-shaped, T-shaped, S-shaped, or irregular shapes.

[0039] In some example operations, the tank 320 can be filled with fluid f so that it is full or nearly full, as shown in FIG. 3 . In such a state, the weight or mass of the fluid f can exert a force on the tank 320, which can exert a force on the protrusion 348 via the guide 350. This can cause the link 336 to move toward the rear of the robot, or to its lowest position, causing the pivot 344 to move. This movement can stretch the biasing element 340 to a length L1, increasing the downward force F1 exerted by the drive wheels 310 on the floor surface 50. That is, movement of the biasing element 340 due to the mass of the fluid f can change the downward force imparted to the drive wheels 310. Although the link 336 is discussed as moving rearward when the tank 320 is full, it can be configured to move in any direction.

[0040] When fluid f is used or dispensed by the mobile cleaning robot 300, such as for a cleaning or mopping operation (as discussed above), fluid height f′ may be lowered as shown in FIG. 3B . This lowering of fluid height f′ reduces the weight or mass of the fluid within the tank 320, allowing upward movement of the tank 320 (caused by the biasing element 340) such that the distance D1 (shown in FIG. 3A ) between the tank 320 and the body 302 is reduced to a distance D2 (shown in FIG. 3B ). This movement of the tank 320 within and relative to the body 302 may result in movement of the protrusion 348. Movement of the protrusion 348 within and together with the guide 350 may result in movement or rotation of the link 336 about the pivot 346, such as to move the link 336 to the position 336′ shown in FIG. 3B . This movement moves pivot 344 closer to pivot 342, reducing the length of biasing element 340 to L2, which may be shorter than length L1. Because biasing element 340 may be a tension spring (or similar biasing element where length affects the force exerted), the shorter length L2 allows a smaller force to be exerted by biasing element 340 on pivot 342. This can cause downward force F2 to be smaller than downward force F1, which helps compensate for the decrease in weight of tank 320 caused by the decrease in fluid height f in tank 320.

[0041] In this manner, the suspension system 335 of the mobile cleaning robot 300 can help passively vary the downward force provided by the drive wheels 310 onto the floor surface 50 based on the amount of fluid f (or the weight of the fluid f) in the tank 320, which can help improve the robot's mobility through the environment and can help improve the cleaning efficiency and effectiveness of the mobile cleaning robot 300 during its mission.

[0042] Although the suspension 335 is discussed as operating with a tank for storing fluid for mopping, the suspension can also be implemented with a dry tank (such as for suction) or wet and dry tanks. In either example, the suspension 335 can be adjusted to increase the downward force of the wheels as the weight of the load increases due to dirt buildup in the load.

[0043] 4 shows a cross-sectional view of a mobile cleaning robot 400. The mobile cleaning robot 400 can be similar to the robot 100 and the mobile cleaning robot 300 discussed above, or the mobile cleaning robot 400 can differ in that its suspension system can provide active control of the length of biasing elements to adjust the downward force of the drive wheels. Any of the robots discussed above or below can be modified to include such components.

[0044] The mobile cleaning robot 400 may include a body 402 and a suspension system 435 including a drive arm 438 coupled to the body at an arm pivot 439. The drive arm 438 may be movable or rotatable relative to the body 402 about the arm pivot 439. The drive arm 438 may also be coupled to the drive wheels 410, such as to support the drive wheels 410. The drive wheels 410 may be engaged with a floor surface 50 to move the mobile cleaning robot 400 around in the environment 40.

[0045] The mobile cleaning robot 400 may also include a container or tank 420 connectable to the body 402. For example, the tank 420 may be positionable or locatable within the body 402. The tank 420 may optionally be detachable from the body 402 of the mobile cleaning robot 400. The tank 420 may be configured to carry a fluid f therein, such as for dispensing by a sprayer or nozzle (e.g., nozzle 116), as discussed above.

[0046] The suspension system 435 may also include a biasing element 440 coupled to the drive arm 438. The biasing element 440 may be any biasing element, such as a tension spring, a compression spring, a spring bar, or a torsion spring. The biasing element 440 may be coupled to the pivot 442 to apply a force to the pivot 442 to bias the drive wheel 410 toward the floor surface 50.

[0047] The suspension system 435 may also include a drive system 452 including a rack 454, a pinion 456, and a bearing 458. The rack 454 may be a toothed rack, such as a straight rack or a curved rack including teeth that may be engageable or can be made to engage with the pinion 456. The pinion 456 may be coupled to an actuator or motor 460, which may be in communication with a controller (e.g., 112). The motor 460 may be operable to rotate the pinion 456. The bearing 458 may be coupled to the pinion 456 and may move with the pinion 456. The bearing 458 may be coupled to the biasing element 440 such that the biasing element 440 can move with the pinion 456 and the bearing 458.

[0048] The mobile cleaning robot 400 may also include sensors 462a and 462b (sensors 462) coupled to the body 402 and engaged with the tank 420. One or more of the sensors 462 may be configured to generate a signal based on the weight or mass of the tank 420 and transmit the signal to a controller. One or more of the sensors 462 may be a single-point load cell, a digital load cell, a beam-type load cell, a canister-type load cell, a hydraulic load cell, a strain gauge, a capacitance load cell, a piezoelectric transducer, or the like. Optionally, the sensors 462 may be one or more break beam sensors that can be activated and deactivated to have two set points. In some examples, the fluid height can be determined through fluid height measurement (using a capacitive height sensor, a resistive height sensor, a magnetic height sensor, or the like). The height sensor may be used by a controller or the like to determine the load on the tank.

[0049] In some example operations, the tank 420 can be filled with fluid f to a height f so that the tank 420 is full or relatively full, such as at the start of a cleaning or mopping mission. The sensor 462 can measure the weight or mass of the tank 420 and the fluid f therein (or can sense the fluid as it is dispensed) and can send a signal to a controller based on the sensed or detected mass or load. The controller can determine the mass of the tank based on the load signal and can command or operate the motor 460 to operate the pinion 456 to rotate and move along the rack 454. For example, when the controller determines that the fluid level is full or the load is high, it can operate the motor 460 to drive the pinion 456 to the farthest rear portion of the rack 454, which can move or extend the biasing element 440 to its maximum length, increasing the force applied by the biasing element 440 to the drive arm 438 and increasing the downward force applied by the drive wheel 410 to the floor surface 50.

[0050] As fluid f is used by the mobile cleaning robot 400, the fluid height may decrease, causing the mass or weight of the tank 420 to decrease. The change may be sensed by the sensor 462, which may alter the load signal sent by the sensor 462 to the controller. The controller may then determine that the weight has decreased (or changed), and therefore that the downward force that needs to be imparted by the drive wheels 410 is relatively small. The controller may then operate the motor 460 to drive the pinion 456 to rotate and move along the rack 454, such as toward the front of the body 402, to shorten the length of the biasing element 440. The reduction in the length of the biasing element 440 may reduce the force applied to the drive arm 438, thereby reducing the downward force applied by the drive wheels 410 to the floor surface 50.

[0051] In this manner, the suspension system 435 of the mobile cleaning robot 400 can be actively controlled by the controller of the mobile cleaning robot 400 to adjust the downward force provided by the drive wheels 410 based on the fluid height in the tank 420. Active control of the downward force can help improve the robot's mobility through the environment and can help improve the cleaning efficiency and effectiveness of the mobile cleaning robot 400 during the course of a mission.

[0052] Network Example 5 is a diagram illustrating an example of a communication network 500 that can enable networking between a mobile robot 501 and one or more other devices, such as a mobile device 504, a cloud computer system 506, or another autonomous robot 508 separate from the mobile robot 501. The network below is discussed with the robot 501 as the primary robot, although the robot 508 could also be the primary robot.

[0053] Using the communications network 510, the robot 501, the mobile device 504, the robot 508, and the cloud computer system 506 can communicate with each other to send and receive data from each other. In some examples, the robot 501, the robot 508, or both the robot 501 and the robot 508 communicate with the mobile device 504 through the cloud computer system 506. Alternatively or additionally, the robot 501, the robot 508, or both the robot 501 and the robot 508 communicate directly with the mobile device 504. Various types and combinations of wireless networks (e.g., Bluetooth, radio frequency, optical-based, etc.) and network architectures (e.g., mesh networks) may be employed by the communications network 510.

[0054] In some examples, the mobile device 504 may be a remote device that can be tethered to the cloud computer system 506 and to which a user can provide input. The mobile device 504 may include user input elements, such as one or more of a touchscreen display, buttons, a microphone, a mouse, a keyboard, or other devices that respond to input provided by a user. The mobile device 504 may include an immersive medium (e.g., virtual reality) with which the user interacts to provide input. In these examples, the mobile device 504 may be a virtual reality headset or a head-mounted display.

[0055] A user can provide input corresponding to a command to the mobile robot 501. In such a case, the mobile device 504 can send a signal to the cloud computer system 506, causing the cloud computer system 506 to send the command signal to the mobile robot 501. In some implementations, the mobile device 504 can present an augmented reality image. In some implementations, the mobile device 504 can be a smartphone, a laptop computer, a tablet computer device, or other mobile device.

[0056] According to some examples discussed herein, the handheld device 504 may include a user interface configured to display a map of the robot's environment. A robot path, such as that specified by a range planner, may be displayed on the map. The interface can receive user commands to modify the environment map by, among other things, adding, removing, or modifying no-go zones in the environment, adding, removing, or modifying intensive cleaning zones in the environment (such as areas requiring repeated cleaning), restricting the robot's travel direction or pattern in portions of the environment, or adding or modifying a cleaning order.

[0057] In some examples, communication network 510 may include additional nodes. For example, a node of communication network 510 may include an additional robot. A node of communication network 510 may also include a network-connected device capable of generating information about environment 40. Such a network-connected device may include one or more sensors, such as an acoustic sensor, an image acquisition system, or other sensor that generates a signal, to detect characteristics of environment 40 from which features can be extracted. A network-connected device may be a home camera, a smart sensor, or the like.

[0058] In the communication network 510, the wireless links may utilize various communication schemes, protocols, etc., such as, for example, Bluetooth varieties, Wi-Fi, Bluetooth Low Energy 802.15.4 (also known as BLE), Worldwide Interoperability for Microwave Access (WiMAX), infrared channels, or satellite spectrum. In some examples, the wireless links may include any cellular communication standard used to communicate between mobile devices, including, but not limited to, standards qualified as 1G, 2G, 3G, 4G, or 5G. When utilized, the network standard may qualify as one or more generations of a cellular communication standard by implementing a specification or standard, such as, for example, a specification administered by the International Telecommunication Union. For example, the 4G standard may correspond to the International Mobile Telecommunications Advanced (IMT-Advanced) specification. Examples of cellular network standards include AMPS, GSM, GPRS, UMTS, LTE, LTE Advanced, Mobile WiMAX, and WiMAX-Advanced. Cellular network standards may use a variety of channel access methods, such as FDMA, TDMA, CDMA, or SDMA.

[0059] FIG. 6 shows a block diagram of an example machine 600 in which any one or more of the techniques (e.g., methodologies) discussed herein can be implemented. The example can include or operate by logic or some components or mechanisms in machine 600, as described herein. Circuitry (e.g., processing circuitry) is a collection of circuitry embodied in the tangible entity of machine 600, including hardware (e.g., simple circuits, gates, logic, etc.). The building blocks of circuitry may be flexible over time. Circuitry includes building blocks that, when operating, can perform specific operations, either alone or in combination. In an example, the hardware of the circuitry can be invariably designed (e.g., hardwired) to perform specific operations. In an example, the hardware of the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) that include machine-readable media that are physically changed (e.g., magnetically, electrically movable arrangements of invariable mass particles, etc.) to encode instructions for specific operations. When connected to a physical component, the underlying electrical properties of the hardware component are changed, for example, from an insulator to a conductor, or vice versa. The instructions, when in operation, enable the embedded hardware (e.g., an execution unit or loading mechanism) to create, via variable connections, building blocks of hardware circuitry to perform a portion of a particular operation. Thus, in examples, a machine-readable medium element is part of the circuitry or is communicatively connected to other components of the circuitry when the device is in operation. In examples, any one of the physical components may be used in more than one member of two or more circuitries. For example, under operation, an execution unit may be used in a first circuit of a first circuitry at one time and then used again by a second circuit in the first circuitry or a third circuit in the second circuitry at a different time. Examples of the addition of these components to machine 600 are as follows:

[0060] In alternative embodiments, machine 600 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, machine 600 may operate in a server machine, a client machine, or both capacities in a server-client network environment. In an example, machine 600 may act as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. Machine 600 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web appliance, a network router, switch, or bridge, or any machine capable of executing instructions (serially or otherwise) that specify actions to be taken by that machine. Furthermore, although only a single machine is shown, the term “machine” should be interpreted to include any collection of machines individually or together that execute a set (or sets) of instructions to implement any one or more of the methodologies described herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations, etc.

[0061] The machine (e.g., computer system) 600 may include hardware processing units 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), hardware processor cores, or any combination thereof), some or all of which may communicate with each other via an interlink (e.g., a bus) 630; a main memory 604; static memory (e.g., memory or storage for firmware, microcode, basic input / output system (BIOS), unified extensible firmware interface (UEFI), etc.) 606; and mass storage device 608 (e.g., a hard drive, tape drive, flash storage, or other block device). The machine 600 may further include a display device 610, an alphanumeric input device 612 (e.g., a keyboard), and a user interface (UI) navigation device 614 (e.g., a mouse). In an example, the display device 610, the input device 612, and the UI navigation device 614 may be touchscreen displays. Machine 600 may additionally include a storage device (e.g., a drive unit) 608, a signal generator 618 (e.g., a speaker), a network interface device 620, and one or more sensors 616, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensor. Machine 600 may include an output controller 628, such as serial (e.g., Universal Serial Bus (USB)), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) communication, for communication with or control of one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0062] The processing unit 602, main memory 604, static memory 606, or mass storage device 608 may be or comprise a machine-readable medium 622 on which is stored one or more sets of data structures or instructions 624 (e.g., software) that embody or are utilized by any one or more of the techniques or functions described herein. The instructions 624 may reside, completely or at least partially, within any of the registers of the processing unit 602, main memory 604, static memory 606, or mass storage device 608 during execution by the machine 600. In an example, one or any combination of the processing unit 602, main memory 604, static memory 606, or mass storage device 608 may constitute the machine-readable medium 622. Although the machine-readable medium 622 is illustrated as a single medium, the term “machine-readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store one or more instructions 624.

[0063] The term "machine-readable medium" may include any medium capable of storing, encoding, or carrying instructions for execution by machine 600 and causing machine 600 to perform any one or more of the techniques of this disclosure, or any medium capable of storing, encoding, or carrying data structures used by such instructions or data constructs associated with such instructions. Non-limiting examples of machine-readable media may include solid-state memory, optical media, magnetic media, and signals (e.g., radio frequency signals, other photon-based signals, audio signals, etc.). In an example, a non-transitory machine-readable medium comprises a machine-readable medium with a plurality of particles having a fixed (e.g., stationary) mass and is thus a composition of matter. Thus, a non-transitory machine-readable medium is a machine-readable medium that does not include a transiently propagating signal. Examples of non-transitory machine-readable media may include non-volatile memory such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices, magnetic disks such as internal hard disks and removable disks, magneto-optical disks, CD-ROM disks and DVD-ROM disks.

[0064] The instructions 624 may further be transmitted or received over a communications network 626 using a transmission medium via a network interface device 620 utilizing any one of several transport protocols (e.g., Frame Relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), etc.) Examples of communications networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile telephone network (e.g., a cellular network), a Power On Telephone Service (POTS) network, and a wireless data network (e.g., the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, the IEEE 802.16 family of standards known as WiMax®, the IEEE 802.15.4 family of standards, a peer-to-peer (P2P) network, among others. In an example, the network interface device 620 may include one or more physical jacks (e.g., Ethernet, coaxial, or telephone jacks) or one or more antennas for connecting to the communications network 626. In an example, the network interface device 620 may include multiple antennas for wireless communication using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO). The term “transmission medium” should be interpreted to include any intangible medium capable of storing, encoding, or carrying instructions for execution by the machine 600, including digital or analog communications signals or other intangible media to facilitate communication of such software. Transmission media are machine-readable media.

[0065] Notes and Examples The following non-limiting examples, detailing specific aspects of the present subject matter, among other things, solve the problems and provide the benefits discussed herein.

[0066] Example 1 is a mobile cleaning robot movable within an environment, the mobile cleaning robot comprising: a body; a drive arm coupled to the body and movable relative to the body, the drive arm supporting a drive wheel; a container coupleable to the body and configured to carry a fluid therein; a biasing element coupled to the drive arm to bias the drive wheel toward a floor surface; and a link pivotally coupled to the body and coupled to the biasing element, the link engageable with the container to adjust the biasing element based on the amount of fluid in the tank.

[0067] In Example 2, the subject matter of Example 1 optionally includes, wherein moving the biasing element varies the downward force imparted to the drive wheel.

[0068] In Example 3, the subject matter of Example 2 optionally includes, wherein the link is coupled to the tank through at least one of a sliding engagement and a pivoting engagement.

[0069] In Example 4, the subject matter of Example 3 optionally includes, wherein the link is coupled to a first lateral side of the tank.

[0070] In Example 5, the subject matter of Example 4 optionally includes a second link coupled to a second lateral side of the tank opposite the link and the first lateral side of the tank, and a second biasing element coupled to the second drive arm for biasing a second drive wheel coupled to the second drive arm toward the floor surface.

[0071] In Example 6, the subject matter of any one or more of Examples 1-5 optionally includes, wherein the biasing element comprises a tension spring.

[0072] In Example 7, the subject matter of any one or more of Examples 1-6 optionally includes, wherein the tank is configured to move vertically based on an amount of fluid in the tank.

[0073] In Example 8, the subject matter of Example 7 optionally includes causing the link to at least one of slide or rotate relative to the body, wherein the vertical movement of the tank causes the link to at least one of slide or rotate relative to the body.

[0074] Example 9 is a mobile cleaning robot movable within an environment, the mobile cleaning robot comprising: a body; a drive wheel arm coupled to the body and movable relative to the body, the drive wheel arm supporting the drive wheel; a tank coupleable to the body and configured to receive and hold a fluid therein; a biasing element coupled to the drive arm to bias the drive wheel toward a floor surface; an actuator coupled to the body and the biasing element; a transducer coupled to the tank and configured to generate a load signal based on the amount of fluid in the tank; and a controller configured to determine a mass of the tank based on the load signal and to operate the actuator based on the determined mass to adjust the biasing element.

[0075] In Example 10, the subject matter of Example 9 optionally includes wherein the actuator comprises a rack coupled to the body, and the actuator comprises a pinion engaged with the rack, the pinion coupled to the biasing element and drivable to move the pinion along the rack to adjust the length of the biasing element.

[0076] In Example 11, the subject matter of any one or more of Examples 9-10 optionally includes, wherein moving the biasing element varies a downward force imparted to the drive wheel.

[0077] In Example 12, the subject matter of Example 11 optionally includes, wherein the actuator is coupled to a first lateral side of the tank.

[0078] In Example 13, the subject matter of Example 12 optionally includes a second actuator coupled to a second lateral side of the tank opposite the actuator and the first lateral side of the tank.

[0079] In Example 14, the subject matter of any one or more of Examples 9-13 optionally includes wherein the biasing element comprises a tension spring and the transducer comprises a load cell.

[0080] Example 15 is a mobile cleaning robot movable within an environment, the mobile cleaning robot comprising: a body; drive wheels coupled to the body and engageable with a floor surface; a container coupleable to the body and configured to receive and hold a mass therein; a biasing element coupled to the drive wheels to bias the drive wheels toward the floor surface; and a link coupled to the body and the biasing element, the link engageable with the container to adjust the force applied by the drive wheels based on the mass carried by the container.

[0081] In Example 16, the subject matter of Example 15 optionally includes, wherein moving the biasing element varies the downward force imparted to the drive wheel.

[0082] In Example 17, the subject matter of Example 16 optionally includes, wherein the link is coupled to the container through at least one of a sliding engagement and a pivoting engagement.

[0083] In Example 18, the subject matter of Example 17 optionally includes, wherein the link is positioned on a first lateral side of the tank.

[0084] In Example 19, the subject matter of Example 18 optionally includes a second link positioned on a second lateral side of the tank opposite the link and the first lateral side of the tank, and a second biasing element coupled to the second drive arm for biasing a second drive wheel coupled to the second drive arm toward the floor surface.

[0085] In Example 20, the subject matter of any one or more of Examples 15-19 optionally includes, wherein the tank is configured to move vertically based on the amount of fluid in the container.

[0086] In Example 21, the apparatus or method of any one or any combination of Examples 1 through 20 may be optionally configured such that all of the elements or options described are available for use or selection.

[0087] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. Furthermore, the inventors also contemplate examples that use any combination or permutation of those elements (or one or more aspects thereof) shown or described, either with respect to the specific example (or one or more aspects thereof) or with respect to any other example (or one or more aspects thereof) shown or described herein.

[0088] In the event of a conflicting usage between this document and any document incorporated by reference, the usage in this document controls. The terms "including" and "in which" are used herein as the plain English equivalents of the respective terms "comprising" and "wherein." Also, in the appended claims, the terms "including" and "comprising" are open-ended, i.e., systems, devices, articles, compositions, formulations, or methods that include elements in addition to the elements listed after such term in a claim are still deemed to be within the scope of that claim.

[0089] The above description is intended to be illustrative, not limiting. For example, the examples described above (or one or more aspects thereof) can be used in combination with each other. Other embodiments may be utilized by those skilled in the art upon reviewing the above description. The Abstract is provided to comply with 37 CFR §1.72(b) to allow the reader to quickly ascertain the nature of the disclosure. The Abstract has been submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be construed as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Accordingly, the following claims are incorporated herein in the Detailed Description as an example or embodiment, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. [Explanation of symbols]

[0090] 40 Environment Rooms 42, 42a, 42b, 42c, 42d, and 42e 44 beds 46 tables 48 Island 50, 50a, 50b, 50c, 50d, 50e floor surface 52 Rugs 60 User 100 Mobile Cleaning Robot 102 Main Unit 103 Outer housing 104, 104a, 104b driving wheels 106 Cleaning Pad 108 Buffer 110, 110a, 110b Actuator, motor 112 Control and processing devices 114 memory 116 Nozzle, discharge port 118 Pump 120 Tanks, containers 122 Sensor System 124 Cliff Sensor 126, 126a, 126b Collision sensors 128 Image Acquisition Device 129 Image Acquisition Device 130 Fault monitoring sensor 132 buttons 134 Lid 136 links 300 Mobile Cleaning Robot 302 Main Unit 320 Containers, tanks 335 Suspension System 336, 336' Link 338 Drive Arm 339 Arm Pivot 340 energizing element 342 Axis 344 Axis 346 Axis 348 Protrusion 350 Information Department 400 Mobile Cleaning Robot 402 Main Unit 410 Drive Wheel 420 Containers, tanks 435 Suspension System 438 Drive Arm 439 Arm pivot 440 energizing element 442 Axis 452 Drive System 454 racks 456 Pinion 458 Bearings 460 Actuators and motors 462, 462a, 462b sensors 500 Communication Network 501 Mobile Robot 504 Mobile Devices 506 Cloud Computer System 508 other autonomous robots 600 machines 602 Hardware Processing Unit 604 Main Memory 606 Static Memory 608 Mass Storage 610 Display device 612 Alphanumeric Input Device 614 User interface running device 616 Sensors 618 Signal Generator 620 Network Interface Device 622 Machine-Readable Medium 624 command 626 Communication Network 628 Output Control Device 630 Interlink D1, D2: Distance between the tank 320 and the body 302 f fluid f', f1 fluid height F1, F2 Downward force L1 length

Claims

1. A mobile cleaning robot capable of moving within an environment, comprising: The main body and a drive arm coupled to the body, the drive arm being movable relative to the body and supporting a drive wheel; a container connectable to the body, the container configured to carry a fluid therein; a biasing element coupled to the drive arm to bias the drive wheel toward a floor surface; a link pivotally connected to the body and connected to the biasing element, the link engageable with the container to adjust the biasing element based on the amount of fluid in the tank; A mobile cleaning robot comprising:

2. The mobile cleaning robot of claim 1 , wherein movement of the biasing element varies a downward force imparted to the drive wheel.

3. The mobile cleaning robot of claim 2 , wherein the link is coupled to the tank through at least one of a sliding engagement and a pivoting engagement.

4. The mobile cleaning robot of claim 3 , wherein the link is coupled to a first lateral side of the tank.

5. a second link coupled to the link and to a second lateral side of the tank opposite the first lateral side of the tank; a second biasing element coupled to the second drive arm for biasing a second drive wheel coupled to the second drive arm toward the floor surface; The mobile cleaning robot of claim 4 further comprising:

6. The mobile cleaning robot of claim 1 , wherein the biasing element comprises a tension spring.

7. The mobile cleaning robot of claim 1 , wherein the tank is configured to move vertically based on the amount of fluid in the tank.

8. 8. The mobile cleaning robot of claim 7, wherein vertical movement of the tank causes the link to at least one of slide and rotate relative to the body.

9. A mobile cleaning robot capable of moving within an environment, comprising: The main body and a drive wheel arm coupled to the body, the drive wheel arm being movable relative to the body and supporting a drive wheel; a tank connectable to the body, the tank configured to receive and retain a fluid therein; a biasing element coupled to the drive wheel arm to bias the drive wheel toward a floor surface; an actuator coupled to the body and the biasing element; a transducer coupled to the tank and configured to generate a load signal based on the amount of fluid in the tank; A control device, determining a mass of the tank based on the load signal; and and operating the actuator based on the determined mass to adjust the biasing element. a control device comprising: A mobile cleaning robot comprising:

10. 10. The mobile cleaning robot of claim 9, wherein the actuator comprises a rack coupled to the body, and the actuator comprises a pinion engaged with the rack, the pinion coupled to the biasing element and drivable to move the pinion along the rack to adjust the length of the biasing element.

11. 10. The mobile cleaning robot of claim 9, wherein movement of the biasing element varies a downward force imparted to the drive wheel.

12. The mobile cleaning robot of claim 11 , wherein the actuator is coupled to a first lateral side of the tank.

13. 13. The mobile cleaning robot of claim 12, further comprising a second actuator coupled to the actuator and to a second lateral side of the tank opposite the first lateral side of the tank.

14. 10. The mobile cleaning robot of claim 9, wherein the biasing element comprises a tension spring and the transducer comprises a load cell.

15. A mobile cleaning robot capable of moving within an environment, comprising: The main body and a drive wheel coupled to the body and engageable with a floor surface; a container connectable to the body, the container configured to receive and retain a mass therein; a biasing element coupled to the drive wheel to bias the drive wheel toward a floor surface; a link coupled to the body and the biasing element, the link engageable with the container to adjust the force applied by the drive wheel based on a mass carried by the container; and A mobile cleaning robot comprising:

16. 16. The mobile cleaning robot of claim 15, wherein movement of the biasing element varies a downward force imparted to the drive wheel.

17. 17. The mobile cleaning robot of claim 16, wherein the link is coupled to the container through at least one of a sliding engagement and a pivoting engagement.

18. 18. The mobile cleaning robot of claim 17, wherein the link is positioned on a first lateral side of the tank.

19. a second link positioned on a second lateral side of the tank opposite the link and the first lateral side of the tank; a second biasing element coupled to the second drive arm for biasing a second drive wheel coupled to the second drive arm toward the floor surface; 20. The mobile cleaning robot of claim 18, further comprising:

20. 16. The mobile cleaning robot of claim 15, wherein the tank is configured to move vertically based on the amount of fluid in the container.

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