STATICALLY STABLE ROBOT USING WHEEL WITH INNER SYSTEM

Abstract

The invention relates to a vehicle including a chassis and a pair of wheels supported in spaced apart relationship by the chassis for rotation about a common axis. A pair of drive modules is associated with the respective wheels. The drive modules and the chassis are connected for rotation as a sub-assembly relative to the wheels about the common axis with the centre of mass of the sub-assembly below the common axis in a static equilibrium position. Each of the drive modules is housed substantially within the respective wheel.

Claims

1. A vehicle including a chassis, a pair of wheels supported in spaced apart relationship by the chassis for rotation about a common axis, and a pair of drive modules associated with the respective wheels, wherein the drive modules and the chassis are connected for rotation as a sub-assembly relative to the wheels about the common axis with the centre of mass of the sub-assembly below the common axis in a static equilibrium position, and wherein each of the drive modules is housed substantially within the respective wheel.

2. A vehicle according to claim 1, wherein the centres of mass of the drive modules in the static equilibrium position are disposed substantially below the common axis, to counterbalance the chassis and thereby allow the centre of mass of the chassis and any associated payload to be stably positioned substantially above the common axis.

3. A vehicle according to claim 1, wherein the drive modules are substantially frontally occluded by the respective wheels.

4. (canceled)

5. A vehicle according claim 1, wherein each of the drive modules includes at least a drive motor.

6. (canceled)

7. (canceled)

8. A vehicle according claim 1, wherein the drive modules include a computerised control module.

9. A vehicle according to claim 1, wherein the drive modules include additional counterweights, thereby to enable the chassis to support payloads with relatively higher centres of mass.

10. (canceled)

11. A vehicle according to claim 1, wherein the chassis includes a primary support platform adapted to support a payload.

12. A vehicle according to claim 11, wherein the payload includes apparatus and systems whereby the vehicle is adapted to function substantially autonomously.

13. A vehicle according to claim 11, wherein the primary support platform is counterbalanced such that the primary platform is predominantly supported at a level above the wheels of the vehicle.

14. A vehicle according to claim 11, wherein the primary support platform is adapted for use as a launch pad for one or more supplementary vehicles.

15. A vehicle according to claim 14, wherein the primary support platform is configured to include one or more docking stations enabling periodic battery charging or refilling for the one or more supplementary vehicles.

16. (canceled)

17. A vehicle according to claim 1, wherein the chassis is adapted to support one or more solar panels, to provide electric power for the drive motors and thereby extend vehicle runtime.

18. A vehicle according to claim 1, wherein the chassis is adjustable in length, thereby allowing the track between the wheels to be selectively adjusted.

19. A vehicle according to claim 1, wherein the chassis is selectively adjustable in height for obstacle avoidance and/or path optimisation.

20. A vehicle according to claim 1, wherein the vehicle includes a dynamic stability control system adapted to reduce tilting oscillations around the common axis.

21. A vehicle according to claim 1, wherein an angular orientation of the chassis, relative to the drive modules in the static equilibrium position, is selectively adjustable about the common axis.

22. A vehicle according to claim 1, wherein one or more additional wheels is incorporated between, in front of or behind the pair of wheels for stability, supplementary drive capacity and/or additional load bearing capacity.

23. A vehicle according to claim 22, wherein one or more additional wheels are supported for rotation on the common axis.

24. A vehicle according to claim 23, wherein the or each additional wheel incorporates a steering mechanism.

25. A vehicle according to claim 24, wherein two or more of the vehicles are coupled together by means of an interconnecting assembly, thereby to create a composite vehicle with four or more wheels.

26. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0031] FIG. 1 is a perspective view showing a di-wheel vehicle according to a first embodiment of the invention;

[0032] FIG. 2 is a perspective view of the vehicle of FIG. 1, with a wheel cover removed to reveal the respective internal drive module;

[0033] FIG. 3 is a perspective view of the vehicle of FIG. 2, in a forwardly inclined orientation, depicting rotation of the drive modules and chassis as a subassembly relative to the wheels;

[0034] FIG. 4 is a perspective view of the vehicle of FIGS. 1 to 3, wherein the chassis incorporates a support platform;

[0035] FIG. 5 is an exploded perspective view of the vehicle of FIG. 4, showing one of the drive modules in more detail;

[0036] FIG. 6 is an enlarged perspective view of the drive module from FIG. 5;

[0037] FIG. 7 is a partially transparent perspective view of a vehicle according to a further embodiment of the invention, in which the support platform incorporates a solar panel;

[0038] FIG. 8 is a front elevation view of the vehicle of FIG. 7, showing occlusion of the drive modules within the respective wheels, permitting the chassis to be predominantly supported at a height well above the rotational axis of the wheels in a statically stable equilibrium position;

[0039] FIG. 9 is a perspective view showing a further embodiment of the invention, in which the angular orientation of the chassis is adjustable relative to the drive modules; and

[0040] FIG. 10 is a perspective view showing another embodiment of the invention in which the angular orientation of the support platform is adjustable relative to the drive modules, independently of the chassis.

PREFERRED EMBODIMENTS OF THE INVENTION

[0041] Referring initially to FIGS. 1 to 3, the invention provides an omni-directional di-wheel vehicle 1 including a chassis 2, a pair of wheels 3 supported in spaced apart relationship by the chassis for rotation about a common axis 4, and a pair of drive modules 5 associated with the respective wheels. The wheels may incorporate integral treads or tyres as required for the intended application.

[0042] The chassis 2 includes a transverse bridge section 10, and a pair of legs 12 extending generally downwardly from opposite sides of the bridge section. The legs 12 are connected at their lower ends to the respective drive modules 5 by means of lugs 14 and tubular axle formations 15, which in turn support the respective wheels for independent rotation about the common axis, as described more fully below. The drive modules 5 and the chassis 2 are thereby interconnected via the tubular axle formations as a discrete subassembly 16 for rotation relative to the wheels about the common axis 4.

[0043] The combined centre of mass of the sub-assembly 16 is at a level substantially below the common axis in a static equilibrium position of the vehicle. This configuration allows the chassis and any associated payload or supplementary system components to be positioned well above the wheel axis, with the combined mass of the chassis and payload effectively counterbalanced by the substantial combined mass of the drive modules positioned below the wheel axis.

[0044] In this way, it will be appreciated that whenever the sub-assembly incorporating the chassis is rotated forwardly or rearwardly away from the generally upright equilibrium position, for example to the forward orientation as shown in FIG. 3, a gravitationally induced restoring force will tend to return the sub-assembly to the statically stable equilibrium position. Under static load conditions, this restoring force will progressively increase with the extent of angular deviation of the sub-assembly from the equilibrium position with a maximum force occurring at an angle of +/90.

[0045] As best seen in FIGS. 5 and 6, the primary components of each of the drive modules 5 include a counterweight 20, batteries 21, an electric motor 22, a toothed drive belt 23 for the motor, and electronics enclosures 24 containing computer modules, motor controllers, power regulators, sensors and the like.

[0046] Each wheel includes a drive hub assembly 30, fixedly connected to the respective wheel and adapted to be rotatably mounted by means of bearings to a reduced diameter section 31 of the respective axle 15. The outer circumferential periphery of the drive hub incorporates teeth for engagement with the complementary internal teeth on the drive belt. As best seen in FIG. 6, the drive belt also engages a toothed drive pinion 35 on an output drive spindle of the motor, thereby to transmit drive from the motor to the wheel via the belt and drive hub.

[0047] It will be appreciated that in further embodiments, other forms of drive motor such as hydraulic or pneumatic motors and other forms of transmission such as chains and sprockets, or gears trains or gearboxes, as well as direct drive mechanisms, may additionally or alternatively be used. In one such embodiment (not shown) an electric drive motor is integrated coaxially into the axle formation 15, with the tubular body of the axle formation integrated with a stator for the motor.

[0048] As best seen in FIGS. 5 and 6, the various components of the drive modules, including the counterweights, are specifically sized, shaped and configured to be entirely or at least predominantly housed within complementary generally cylindrical cavities 40 formed within the respective wheels. In this way, the drive modules in use are wholly or at least substantially frontally occluded by the wheels, as best seen in FIG. 8.

[0049] In the embodiments shown, the wheel cavities are enclosed by removable outer covers 48 to protect the drive modules from mechanical damage and to minimise the ingress of dust or debris. In other embodiments, however, the wheel cavities may be partially or substantially open. Spoked, slotted or perforated wheels and/or wheel covers may also be used.

[0050] In the embodiment shown in FIGS. 4 and 5, the chassis 2 includes a primary support platform 50 adapted to support a payload. The support platform shown is curved with a radius similar to that of the wheels, such that the platform acts as an integral wheel guard while minimising the overall space occupied by the vehicle. However, support platforms and other support structures may be incorporated in a wide variety of shapes, sizes and configurations, according to the intended application. For example in the embodiment shown in FIGS. 7 and 8, the primary support platform 50 is adapted to support a solar panel 52, to provide supplementary electrical power for the drive motors and/or ancillary electrical equipment and prolong run time between battery charges.

[0051] In some embodiments, the support platform or the associated payload includes components and systems whereby the vehicle is adapted to function autonomously or substantially autonomously, as an omni-directional mobile platform for a robot. Examples of such components and systems include: [0052] sensors suited to the intended application (such as ranging, imaging, localisation or inertial sensors), [0053] actuators or instruments suited to the intended application (such as manipulators, robotic arms, pan/tilt mechanisms, agricultural planting, weeding, spraying or harvesting mechanisms, drilling or mining tools, firefighting tools including water nozzles or chemical sprayers, weapons systems, medical instruments or devices, research or analytical instruments or tools, or lifting and positioning tools for logistics or materials handling), [0054] lighting systems (such as laser, UV, IR, LED or floodlighting systems), [0055] energy generation or conservation equipment (such as solar panels, sails, wind turbines or fuel cells), and/or [0056] ancillary electronic equipment (such as computers, data storage media, communications or navigation equipment, antennas or networking components).

[0057] In one embodiment, the support platform is adapted to support one or more robotic arms or other robotic devices. The platform may also be adapted for use as a launch pad for one or more other autonomous or supplementary support vehicles such as UAVs, UGVs, AUVs or other teleoperable devices.

[0058] One particularly advantageous form of the invention is adapted for agricultural applications, whereby the vehicle is used to traverse successive rows of planted vines, crops or trees to carry out monitoring and manipulation tasks such as pest detection, surveillance, mapping, yield estimation, planting, weeding, pruning, watering, fertilising or harvesting. For these purposes, the vehicle may include suitable combinations of sensing, computing and manipulation equipment such as cameras, lasers, radar scanners, robotic arms, spray nozzles, plotters and the like.

[0059] In some embodiments (not shown) the bridge section of the chassis is also adjustable in length, for example by means of telescopically extensible rods or rails, thereby allowing the track between the wheels to be selectively adjusted. If required, adjustment of chassis length may be effected on the fly, in response to control inputs from the control system, to assist the vehicle to navigate obstacles or varying terrain conditions. In some embodiments, the height of the chassis and/or the support platform is adjustable. In some embodiments, the mass of the counterweight in each drive module is selectively adjustable, for example by installing or removing discrete weight modules formed from a heavy material such as iron or lead, or by adding or removing a liquid such as water from ballast tanks incorporated into the drive modules.

[0060] In addition to the static stability inherent in the vehicle, passive damping mechanisms as well as active control systems may also be incorporated to enhance dynamic stability. Such systems may include gyroscopic or inertial sensors, supplementary drive motors, active damping systems and other elements as required. Additional wheels, skids, props or suspension elements may also be provided to enhance stability or to limit the maximum extent of angular deviation of the chassis from the static equilibrium position, if needed. The vehicle preferably also includes dynamic control systems utilising various sensors and other elements outlined above to improve or optimise operational efficiency, regulate power consumption, minimise dynamic oscillations, avoid obstacles and/or optimise navigation and path following strategies.

[0061] In the embodiment of FIG. 9, the angular orientation of the chassis and the associated support platform is selectively adjustable about the common axis, relative to the drive modules in the static equilibrium position. This may be advantageous for a variety of purposes, for example to orientate a solar panel on the support platform optimally toward the sun, to orientate a sail or blade for wind-assisted propulsion, to level the platform when operating on inclined terrain, to level the platform in compensation for unbalanced payloads, or to counteract the effect of dynamic forces during acceleration or deceleration of the vehicle. In this embodiment, the rotational adjustment is effected by rotation of the lugs 14 and hence the legs 12 of the chassis about the respective axles 15.

[0062] A variation of this embodiment is shown in FIG. 10. In this case, however, it will be seen that the rotational orientation of the legs 12 and other primary components of the chassis is fixed relative to the drive modules in the static equilibrium. However, the support platform 50 is rotatable about the common axis relative to the chassis, by means of radial support arms 55 which are connected to the respective axles 15. In this case, the rotational adjustment of the orientation of the primary support platform about the common axis with respect to the drive modules is effected by rotation of the arms 55 about the respective axles 15, independently of the chassis.

[0063] In variations of this embodiment, a supplementary support platform may also be mounted to the bridge section of the chassis itself. This enables some components or payloads on the supplementary support platform to be maintained in a substantially horizontal orientation, while simultaneously allowing other components on the primary support platform, such as solar panels, to be optimally inclined for particular operational purposes (or vice versa).

[0064] It will be appreciated that the invention in its various preferred embodiments provides a vehicle or mobile platform with a number unique features and advantages. By enabling the primary components of the drive modules such as batteries, motors, and controllers as well as additional counterweights to be substantially contained inside and positioned low within the respective wheels, the chassis bridge and payload can be positioned well above the wheel axis with the combined mass effectively counterbalanced by the drive modules. This lowers the overall centre of mass while providing significantly increased ground clearance within the footprint or wheel track of the vehicle. The inherent stability of the vehicle obviates the need for additional wheels, which in turn obviates the need for a separate steering mechanism, whether based on wheel pivoting or skid-steering systems. This reduces manufacturing cost due to the relatively small number of components and the inherent simplicity of the design, while increasing operational efficiency and manoeuvrability, in a highly flexible, adaptable and compact vehicle platform.

[0065] In particular, the ability to rely on extremely low positioning of the centre of mass of the drive modules improves static stability and thereby enables relatively higher payload masses or higher positioning of the payload on the chassis relative to previously known di-wheel vehicles. In some embodiments, the support platform may even be positioned above the maximum wheel height, thereby providing substantially greater ground clearance than even conventional wheeled vehicles, or vehicles with conventional axle arrangements. High manoeuvrability and omni-directionality is derived from the ability of the vehicle to pivot around its central vertical axis (by driving the wheels at equal speed in opposite directions). At the same time, vehicle motion is inherently efficient, since no wheels are required to drag or skid (assuming point contact for the wheels or tyres) during rolling or turning in any direction. In these and other respects, the invention represents a practical and commercially significant improvement over the prior art.

[0066] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.