WHEELS

PRIORITY CLAIM

[0001] This application claims priority from Singapore Patent Application No. 10201904295V filed on 13 May 2019.

TECHNICAL FIELD

[0002] The present invention generally relates to robotic devices, and more particularly relates to robotic devices and systems with passive reconfigurable wheels.

BACKGROUND OF THE DISCLOSURE

[0003] In modem construction, suspended ceilings are widely used in concealing the multiple communication cables, fire safety pipelines, or power cables in residential, commercial and industrial buildings. Along with suspended ceilings comes pest infestation, where the dark and dusty space over the suspended ceiling fosters pest habitations and breeding, which poses a health hazard. Timely and regular inspection and cleaning of suspended ceilings is thus essential.

[0004] The narrow space above the suspended ceiling makes it challenging for human inspection. Robots for structural inspection and diagnosis of industrial structures such as pipelines, ship hulls, and boiler tubes using a mobile platform are known in the art. However, these robots are not suitable for suspended ceiling inspection as they are typically heavy in weight and do not navigate across obstacles easily.

[0005] Thus, there is a need for a lightweight and agile robotic device that is capable of moving on different surfaces for suspended ceiling inspection and cleaning. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.

SUMMARY

[0006] According to at least one aspect of the present embodiments, a passive reconfigurable wheel for moving on different surfaces is provided. The wheel includes: a hub; a plurality of spokes, wherein an inner end of each of the plurality of spokes integrally connects to the hub, and an outer end of each of the plurality of spokes has a stopper fixedly attached thereto; and a plurality of curved limbs, wherein a first end of each of the plurality of curved limbs pivotally connects to the outer end of one of the spokes via a compliant means, and a second end of each of the plurality of curved limbs detachably couples to the first end of an adjacent curved limb via the stopper; wherein the wheel passively reconfigures from a rotational state to a partially compressed state by the second end of one of the plurality of curved limbs detaching from the respective stopper while the compliant means of the one of the plurality of curved limbs is compressed.

[0007] According to another aspect of the present embodiments, a robotic device for moving on different surfaces is provided. The robotic device includes a plurality of the passive reconfigurable wheels, a chassis having a central axis in a locomotion direction, and a plurality of motors fixedly connected to the chassis and rotatably connected to the plurality of the wheels. The robotic device may further include a dropping collection mechanism to pick up and collect droppings from the surface for cleaning purpose. [0008] And according to a further aspect of the present embodiments, a robotic system for suspended ceiling inspection is provided. The robotic system includes the robotic device, an actuation system for actuating the robotic device, and a control system in wireless communication with the actuation system. The robotic system can also be used for suspended ceiling cleaning by including a dropping collection system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to illustrate various embodiments and to explain various principles and advantages in accordance with present embodiments.

[0010] FIG. 1 depicts an illustration of a front top right perspective view of a passive reconfigurable wheel in accordance with present embodiments.

[0011] FIGs. 2A and 2B depict illustrations of an alternative passive reconfigurable wheel in accordance with the present embodiments, wherein FIG. 2A depicts a front top right perspective view, and FIG. 2B depicts a rear top left perspective view of the wheel with a motor shaft keyway.

[0012] FIG. 3A and 3B depict illustrations of side planar views of the wheel of FIG. 1 in a rotational state and a compressed state, respectively, in accordance with the present embodiments.

[0013] FIG. 4A, 4B, 4C and 4D depict illustrations of side planar views of wheel movements to overcome a height of an inverted T-channel in accordance with the present embodiments. [0014] FIGs. 5A, 5B, 5C, 5D, 5E, 5F and 5G depict illustrations of a robotic device with the wheels of FIGs. 2 A and 2B in accordance with the present embodiments, wherein FIG. 5A depicts a front top right perspective view, FIG. 5B depicts a front planar view, FIG. 5C depicts a rear planar view, FIG. 5D depicts a top planar view, FIG. 5E depicts a bottom planar view, FIG. 5F depicts a right side planar view and FIG. 5G depicts a left side planar view of the robotic device.

[0015] FIG. 6A depicts an illustration of the robotic device of FIG. 5A deployed for inspection of a suspended ceiling in accordance with the present embodiments.

[0016] FIG. 6B depicts an illustration of a robotic device with fall recovery frames for inspection of a suspended ceiling in accordance with the present embodiments.

[0017] FIGs. 6C and 6D depict illustrations of a robotic device with a dropping collection mechanism for inspecting and cleaning a suspended ceiling in accordance with the present embodiments.

[0018] FIG. 7 depicts a block diagram of a robotic system including the robotic device of FIG. 5 A in accordance with the present embodiments.

[0019] And FIG. 8 depicts a block diagram of an actuation system architecture of the robotic system of FIG. 7 in accordance with the present embodiments.

[0020] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been depicted to scale.

DETAILED DESCRIPTION

[0021] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description. It is the intent of present embodiments to present a robotic device and system for suspended ceiling surveillance and inspection using passive reconfigurable wheels to move over different surfaces. The robotic device is advantageously agile and lightweight so that it can maneuver above suspended ceilings and winding spaces where a human cannot easily reach for inspection and surveillance tasks. In an embodiment, the robotic device has particular applications for surmounting a height of an inverted T-channel by a wheel being in a partially compressed state (i.e. one of the curved limbs of the wheel is compressed), where the height of the inverted T-channel is less than the diameter of the wheel. In a further embodiment, the robotic device can include a night vision camera in the robot body (e.g., on the front side of the chassis) to collect images for surveillance of pests and inspection of the suspended ceiling condition. The robotic system for inspecting the suspended ceiling can include a vision system to transfer the images to a PC or other mobile devices (e.g., smartphone, tablet, etc.), which is used to operate the robotic device remotely and functions as a control system of the robotic system. In a further embodiment, the robotic device includes fall recovery frames attached to the wheels, which advantageously prevents the robotic device from falling to and resting on its sides. In a further embodiment, the robotic device may also include a dropping collection mechanism to clean the suspended ceiling while performing an inspection.

[0022] The robotic device in accordance with present embodiments is distinguishable from prior art devices in its design and its ability to maneuver over obstacles. These advantages of the present embodiments are achieved by passive reconfigurable wheels which facilitate the robot to climb an obstacle with height less than the diameter of the wheels. On a planar terrain, the wheels retain a round shape and move in a rotational manner, which provide fast and stable locomotion which results in stable image/video feedback using the camera. Further, the wheels can be attached to the chassis such that the circumference of one wheel overlaps a circumference of an adjacent wheel. Advantageously, the robot can move or overcome a suspended ceiling hanging position without getting stuck. In addition, the geometry of the robot is symmetrical about the transverse plane which passes through axes of each of the wheels, which enhances the robot’s adaptability to move in a flipped-over state or an inverted state.

[0023] The robotic system including the robotic device, a control system, an actuation system, a power system and optionally a vision system is distinguishable from prior art robotic systems in that the robotic device is lightweight and has a small dimension, which make it suitable for suspended ceiling inspection. In an embodiment, the net weight of the robotic device is less than 350 grams, with a dimension of equal or less than 170 mm in length along the central axis, 100 mm in width perpendicular to the central axis and 40 mm in height. In a further embodiment, the chassis and the wheels can be easily manufactured by 3D printing with low costs, using Acrylonitrile butadiene styrene (ABS) or similar materials.

[0024] FIG. 1 depicts a front top right perspective view of an exemplary passive reconfigurable wheel 100. The wheel 100 includes a hub 110 in the center and a plurality of spokes 104 integrally connected to the hub 110. The hub 110 may be in the shape of a disc and may include a bore 102 which allows attachment of the wheel. Each spoke 104 may have an inner end connected to the hub 110, and have a stopper 114 fixedly attached to the opposite outer end of the spoke. The wheel 100 further includes a plurality of curved limbs 106 that form a circumference of the wheel. For each curved limb, a first end pivotally connects to the outer end of a spoke 104 via a compliant means 130, and a second end detachably couples to the first end of an adjacent curved limb via the stopper 114. When moving on a flat surface such as a flat terrain or a slope, the wheel is in a rotational state where the curved limbs 106 are coupled to the adjacent curved limbs via the stopper 114. When an obstacle is encountered, the wheel 100 can passively reconfigure from the rotational state to a partially compressed state when one of the curved limbs contacts the obstacle, by the second end of the one of the curved limbs detaching from the respective stopper 114 while its compliant means 130 is compressed as the one of the curved limbs is compressed by the obstacle.

[0025] FIGs. 2A and 2B depict a front top right and a rear top left perspective views of another exemplary passive reconfigurable wheel 200, respectively. The wheel 200 similarly includes a hub 210, a plurality of spokes 204 integrally connected to the hub, and a plurality of curved limbs 206 forming a circumference of the wheel. In some embodiments, the compliant means 230 which interconnects the spoke 204 and the respective curved limb 206 includes a torsion spring. For example, the compliant means 230 can be an assembly of a bolt, a central shaft, and a torsion spring. The curved limb 206 may have a groove 207 defined therein to allow it to bend inward towards the hub during compression. As shown in FIGs. 2A and 2B, each spoke 204 is interconnected to the respective curved limb 206 via a bolt 231, a central shaft 233, and a torsion spring 235. The passive revolute action is gained using the torsion springs 235 to support the plurality of curved limbs 206. This wheel design helps to navigate on a flat terrain in a rotational state, and one of the spokes 204 together with stoppers 214 attached thereto can act as a leg when the wheel approaches a curb or a level change with aides of the torsion spring compression. Besides a torsion spring, other compliant means may also be used, such as a flexural joint that is transformable between a straight form and a bent form. [0026] While the wheel 100 in FIG. 1 includes one stopper 114 fixedly attached to the outer end of each of the spoke 104, two stoppers 214 are fixedly attached to the outer end of each of the spoke 204 in the wheel 200. One may appreciate that other numbers and designs of stoppers may be possible depending on the geometry of the curved limb and the arrangement of the compliant means 130, 230.

[0027] In some embodiments, the hub 210 may include a bore 202 in the center of the hub to allow connections of the wheel 200 to a motor. In a further embodiment, the hub 210 may include a D- shape motor shaft slot 211 for attaching the wheel 200 to a motor shaft.

[0028] It is shown in the wheels 100 and 200 that four spokes 104, 204 are spaced equidistantly about the hub 110, 210 and four quarter-circular curved limbs 106, 206 are used to form the wheel 100, 200. One may appreciate that the wheel may include a different number of spokes and curved limbs, and the spokes may be spaced in a different arrangement with respect to the hub. Further, the spokes, curved limbs, stoppers and compliant means may be in different designs and geometries without compromising the functionality of the passive reconfigurable wheel.

[0029] FIG. 3A depicts a side planar view of the wheel 100 in a rotational state 300. For a wheel including a bolt, a central shaft and a torsion spring as the compliant means, the torsion spring is preloaded when the wheel is in a rotational state. FIG. 3B depicts an illustration of the side planar view of the wheel in a compressed state 350. In the present embodiment, all the curved limbs detach from the respective stoppers 114 on one end and move inwardly towards the hub. The angular range of the inward motion is governed by the dimensions of the wheel as well as the length of the grooves in the curved limbs. [0030] FIGs. 4A-4D depict side planar views of exemplary wheel movements to overcome a height of an inverted T-channel. In FIG. 4A, the wheel 100 moves on a flat surface in a rotational state 400. In FIG. 4B, the wheel approaches and contacts the inverted T-channel. One of the curved limbs is pressed against the inverted T- channel and compresses the compliant means, which causes the end of the curved limb to detach from the stopper 114 and reconfigures the wheel to a partially compressed state 425. In FIG. 4C, the stopper 114 contacts the top of the inverted T- channel. The curved limb connected to the stopper acts as a leg together with the stopper 114. In FIG. 4D, the wheel surmounts the inverted T-channel. The surmounting maneuver is possible due to the compliant action provided by the torsion spring. As shown above, one may appreciate that the passive reconfigurable wheel can climb an obstacle with a height less than the diameter of the wheel.

[0031] FIGs. 5A-5G depict illustrations of an exemplary robotic device 500 with the passive reconfigurable wheels 200. FIG. 5A depicts a front top right perspective view 510 of the robotic device 500. The exemplary robotic device 500 includes a chassis 501, six wheels 200, and motors (not shown) fixedly connected to the chassis and rotatably connected to the wheels. Preferably, the chassis 501 adopts an airfoil chassis design which aids the robotic device to achieve smooth and secure navigation. In some embodiments, the geometry of the robotic device 500 is symmetrical about transverse plane which passes through all the wheels axes. Advantageously, such geometry enhances its adaptability to move in a flipped-over or inverted state.

[0032] FIG. 5B depicts a front planar view 520 of the robotic device 500. The robotic device 500 may further include controllable intensity LED lights 202 and a camera 204 on the front side of the chassis 501. The camera 204 may be a normal RGB camera, a thermal camera, or a night vision camera for collecting sensory information as required. For use in suspended ceiling inspection and surveillance, the camera 204 is preferably a Wi-Fi enabled HD night vision camera for collecting images or videos of the suspended ceiling condition in a dark environment. When the robotic device 500 moves on a planar terrain, the wheels 200 retain its shape and move in a rotational state with fast and stable locomotion such that stable image/video feedback using the camera 204 can be provided.

[0033] FIG. 5C depicts a rear planar view 530 of the robotic device 500. The robotic device 500 may further include a switch 506 on the rear side of the chassis 501 in connection with the motor driver to control an on/off powered state of the robotic device 500.

[0034] FIGs. 5D and 5E depict a top planar view 540 and a bottom planar view 550 of the robotic device 500, respectively. In some embodiments, the robotic device 500 further includes housings 508 for placing the motors. In the present embodiment, the six housings 508 are different in their widths, with the two housings in the middle wider than the others. This is to allow the six wheels 200 to be arranged with different distances from the central axis L of the chassis (the vertical dotted line), corresponding to the locomotion direction. As a result, the six wheels 200 are attached to the robot body such that the circumference of one wheel overlaps with the adjacent wheel. This arrangement advantageously prevents the robotic device 500 from getting stuck at T-sections, and ensures that the robotic device 500 can move or overcome the hanging position at the construction. Such a systematic wheel arrangement also allows for better stability of the robot and it helps the robot overcome curbs.

[0035] FIGs. 5F and 5G depict a right side planar view 560 and a left side planar view 570 of the robotic device 500, respectively. It is clearly seen that the circumference of the middle wheel overlaps with the circumferences of the adjacent wheels on the side. Furthermore, the transverse plane T is shown in FIGs. 5F and 5G, which is the plane that passes through each of the wheel axes. One can appreciate that the robotic device 500 has a geometry that is symmetrical about the transverse plane T such that it is capable of moving even when flipped upside down.

[0036] FIG. 6A depicts a robotic device 610 deployed for inspection of an exemplary suspended ceiling. Depending on the desired applications, the robotic device 610 can also be deployed in other environments, such as uneven roads, curbs, staircases, or the like. In the present embodiment, the suspended ceiling includes ceiling tiles 601 surrounded by channel beams 602 to support the ceiling tiles. The ceiling tiles 601 are substantially flat, and the channel beams 602 may be inverted T- section or I-section beams with a height. The AS/NZS 2785:2000 standard provides a guideline for the specifications for the suspended ceilings systems for use in residential, commercial and industrial constructions. To enable deployment over the suspended ceiling, the diameters of the wheels of the robotic device 610 is preferably determined based on the height of the channel beams 602. In one embodiment, the channel height according to the AS/NZS 2785:2000 standard is in a range of 40-100 mm, and the diameter of the wheels is selected as 105 mm based on the range of the channel height.

[0037] In some embodiments, the robotic device 610 is made lightweight and compact for suspended ceiling inspection purposes. The chassis 501 and wheels 200 of the robotic device can be 3D printed using Acrylonitrile butadiene styrene (ABS) material or similar materials. The 3D printed ABS robotic device is simple in fabrication, has a low manufacturing cost, and is lightweight. In the present embodiment, the dimension of the robotic device is equal or less than 170 mm in length along the central axis, 100 mm in width perpendicular to the central axis and 40 mm in height. The net weight of the robotic device is less than 350 grams. When deployed for suspended ceiling inspection and surveillance, the robotic device 610 can be remotely controlled, allowing the operator to observe the images and video feedback collected by the built-in camera and to control the movements of the wheeled robotic device. Preferably, the robot device 610 can also save trajectories, navigation information, and images of the surrounding environment in its memory, so that, for example, it can navigate the robotic device 610 for future inspections or allow the robotic device 610 to retreat from the deployed location even when it loses connection to the server.

[0038] FIG. 6B depicts an alternative embodiment of a robotic device 620 for inspection of the suspended ceiling. The robotic device 620 includes four passive reconfigurable wheels 622, with a fall recovery frame 625 attached to each of the wheels. The fall recovery frame 625 may be fixedly or detachably attached to the spokes of the wheel 622, or attached in other suitable manners. As shown in the front top left view of the robotic device 620, the fall recovery frames 625 advantageously allow self-recovery actions even when the robotic device topples down during locomotion, and prevent the robotic device from falling and resting on its side.

[0039] FIG. 6C depicts a bottom planar view of another alternative embodiment of a robotic device 630 for inspection of the suspended ceiling. The robotic device 630 may additionally include a dropping collection mechanism 640 at the bottom of the chassis, which allows the robotic device 630 to pick up droppings and clean the suspended ceiling during the inspection. Referring to FIG. 6D, a rear top right perspective view, a top view and a right side planar view of the exemplary dropping collection mechanism 640 are provided, respectively. In an embodiment, the dropping collection mechanism 640 uses adhesive tape 648 to collect the droppings. The adhesive tape 648 may be provided on an unwinding pulley 645, which unwinds to release the tape. The dropping collection mechanism may further include a first motor

641 for winding the adhesive tape 648 onto a winding alley 644, and a second motor

642 for pushing the adhesive tape 648 towards the suspended ceiling surface. A dead weight block 646 may also be used to push the adhesive tape 648 towards the suspended ceiling, and a sliding rod 647 is provided to constrain the downward movements of the dead weight block 646. A collecting tray 649 is provided to remove and collect the droppings from the adhesive tape when the tape passes through and tray. By collecting the droppings in the collecting tray 649, one can also examine the collected droppings to obtain information on the types of pests breeding in the suspended ceiling. In operation, unused adhesive tape 648 is pulled from the unwinding pulley 645 and brought into proximity with the suspended ceiling surface. After picking up droppings from the suspended ceiling, the droppings are collected in the collecting tray 649 and used adhesive tape is winded onto the winding pulley 644.

[0040] FIG. 7 depicts an exemplary block diagram of a robotic system 700 including the robotic device 500 (or other embodiments such as robotic device 610, 620, 630). The robotic device 500 includes a frame or chassis 501 and wheels 200. The robotic system 700 includes an actuation system 702 for actuating the robotic device 500 and includes a control system 704. The control system 704 can be a mobile device such as a smartphone, a tablet, or a PC, via which the user can control and teleoperate the robotic device 500. The control system 704 is preferably in wireless communication with the actuation system 702. The robotic system 700 also includes a power system 706 for providing the necessary voltages to the subsystems like the robotic device 500 and actuators in the actuation system 702. [0041] The robotic system 700 may additionally include a vision system 708, which provides vision feedback to the control system 702. Preferably, the vision system 708 is a Wi-Fi enabled vision system including a Wi-Fi module for video or image transfer. When the robotic device 500 is teleoperated by the control system 704, real time video feedback can be transferred back to the control system 704 (e.g., mobile device or PC screen) via the vision system 708 for inspection purpose.

[0042] FIG. 8 depicts a block diagram 800 of an exemplary actuation system architecture of the robotic system 700. The actuation system architecture may include a motion controller 801 (e.g., a programmable logic device Arduino, a dedicated digital signal processor, etc.) in communication with the control system 704 (e.g., an Android phone, a tablet etc.) to implement a variety of motion tasks. Further, the actuation system architecture may include one or more actuators M1-M8 (e.g., Pololu Servo Actuators or others) electrically coupled to the motion controller 801. In some embodiments, 13-volt power is supplied to the actuators.

[0043] Thus, it can be seen that the present embodiments provide passive reconfigurable wheels for moving on different surfaces, and robotic devices and systems including such wheels. The robotic devices and systems in accordance with the present embodiments have a robust ability to navigate across flat surfaces and obstacles. With a lightweight design, the robotic devices and systems demonstrate superior applications in suspended ceiling inspection and surveillance.

[0044] While exemplary embodiments have been presented in the foregoing detailed description of the present embodiments, it should be appreciated that a vast number of variations exist. It should further be appreciated that the exemplary embodiments are only examples, and are not intended to limit the scope, applicability, operation, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing exemplary embodiments of the invention, it being understood that various changes may be made in the function and arrangement of steps and method of operation described in the exemplary embodiments without departing from the scope of the invention as set forth in the appended claims.