GB2242173A

GB2242173A - Dynamically balanced vehicle

Info

Publication number: GB2242173A
Application number: GB8908143A
Authority: GB
Inventors: Andrew George Hay
Original assignee: UK Secretary of State for Trade and Industry
Current assignee: UK Secretary of State for Trade and Industry
Priority date: 1989-04-11
Filing date: 1989-04-11
Publication date: 1991-09-25
Also published as: GB8908143D0

Abstract

A dynamically balanced vehicle for carrying a rider and/or a load has structure (16) carried by a single wheel (10) or by two wheels rotatable in parallel planes. The structure (16) carries means (27) for detecting the state of balance of the vehicle and means (20, 24) for driving the or each wheel such that the structure remains balanced above the wheel or wheels whether the vehicle is stationary or moving. The single wheel (10) comprises a frame (11) rotatable on an axle (15) and carrying peripheral rollers (13) each rotatable about an axis which is not parallel to that of the axle (15). The wheel frame (11) and the rollers (13) are driven by separate motors (20, 24) under the control of computer modules (27) and motor control system (26). If rider-less, the vehicle may be driven under remote control by radio or optical command signals. In the two-wheeled vehicle, (Figs. 3, 4), each wheel is driven by a respective servo-motor. One wheel may be able to be raised from the ground for climbing stairs. <IMAGE>

Description

Dynamically Balanced Vehicles The present invention relates to dynamically balanced vehicles.

Statically balanced vehicles, having three or more wheels and a centre of gravity acting along a line passing between ground contact points of the wheels, are the most common form of vehicle.

Dynamically balanced vehicles, having two wheels are also well known in the form of bicycles and motor cycles. Dynamically balanced vehicles have wheels which, in straight line travel of the vehicle, rotate in a single plane about parallel axes. Such a vehicle is balanced, in motion, by the gyroscopic effect of the wheels, and by reflexive adjustment to the angle between the wheel axes and to the relative positions of the centres of gravity of a rider and the machine by the rider. It is possible for a skilled rider to maintain such a vehicle balanced in a stationery position by constant readjustment of the centres of gravity.

Dynamically balanced vehicles in the form of mono-wheeled cycles are also known as entertainment devices for use in balancing acts by, for example, circus and theatre performers.

Two wheeled vehicles other than dynamically balanced ones are also known. In these the wheels rotate in parallel planes about, usually, a single axis (although there might be two adjacent parallel axes).

These are vehicles designed to be towed by humans, vehicles or animals, and examples are golf carts, rickshaws, caravans, trailers and two wheeled animal drawn carriages. In the static position these vehicles rest upon the wheels and attached structure which may be the vehicle body or the vehicle towing means.

Statically balanced vehicles have the disadvantages, in many environments, of occupying a comparatively large area and of being comparatively unmanoeuvrable for regions containing many obstacles.

According to the present invention a dynamically balanced vehicle includes structure carried by a single wheel or two wheels rotatable in parallel planes, driving means for driving the or each wheel, detection means for detecting the state of balance of the vehicle, and control means for controlling the driving means in such a way as to cause the vehicle to remain stationery or to move in a desired direction with the structure balanced above the wheel or wheels. The driving means, detection means and control means may be carried in part or in whole by the structure. The detection means may include, for example, a level sensor or an inclinometer.

According to one form of the invention the vehicle is a mono-wheel, the single wheel having a single frame rotatable about an axis and carrying at its circumference a plurality of rollers rotatable about parallel axes which are substantially not parallel to the frame axis, and the driving means being adapted to independantly drive the frame and at least those rollers contacting a surface.

The driving means may include, for example, direct mechanical gearing, smooth or toothed belts, universal or constant velocity joints, friction drive, crank drive or any combination of these. A typical means might involve direct gearing for a main gear to planet gears attached to the axle of each roller. Offset bevel gears of the type whizz would be required by this type of drive are within the scope of present gearing manufacture. Alternatively a continuous flat or toothed belt may be used to connect the various rollers.

Whilst many types of drive unit are possible direct current electrical servo-motors, which are particularly well adapted for providing the precise speed ratios required for accurate steering of the vehicle, are preferred.

According to another embodiment of the invention the vehicle is a bi-wheel, having two wheels rotatable in parallel planes.

With thins embodiment of the invention the wheels are preferably rotatable about a common axis, but alternatively the axes of rotation might be parallel and closely spaced apart.

The driving means might conveniently include a direct current servometer for each wheel.

The structure for a vehicle according to the invention might be attached to the wheel or wheels by means, such as horizontal and azimuth servo joints, allowing a degree of articulation.

In the case of a two wneel vehicle the articulation is preferably sufficient to enable the vehicle to negotiate steps.

An artificial intelligence device mounted on the structure will be necessary to enable the balancing to be carried out. The structure will also normally carry seating for a rider, loads carrying means, or both.

Riderless vehicles will normally be driven under remote control by radio or optical links.

The problem of balancing a single pole on a cart has been investigated by research workers in the field of artificial intelligence for a number of years, and the successful artificial intelligence means developed to cope with this problem might be adapted for control of vehicles according to the invention.

Wheels similar to those used for the mono-wheel form of the present invention have been known for use on multi-wheeled omnidirectional vehicles for many years. For example a wheel per se providing a continuous circular circumference from a plurality of rollers mounted at an angle on a frame is described in UK Patent 1408820. An article in Robotics Age of February 1984 describes a vehicle using 3 wheels of this type which is the subject of US Patent 4237990. The article also mentions a number of other Patents describing multi-wheeled omnidirectional vehicles. However, in all known vehicles using wheels of this type only the frame is driven, the rollers rotating to allow movement of the vehicle in the driven direction culminating from the various individual wheel drive speeds.

Such wheels, with passive rollers, would not be suitable for the present invention.

Some embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, of which Figure 1. is an end elevation of a mono-wheel vehicle according to the invention, Figure 2. is a side elevation of the mono-wheel used in the vehicle of Fig 1.

Figure 3. is an elevation of a bi-wheel vehicle according to the invention, and Figure 4 is an elevation of another type of bi-wheel vehicle according to the invention.

A mono-wheel vehicle (Fig 1.) has a wheel 10 consisting of a cylindrical frame 11 (see also Fig 2.) rotatable on an axle 15 about an axis 12. Round the periphery of the cylindrical frame 11 are mounted a plurality of rollers, such as shown at 13, rotatable about parallel axes 14 which are not parallel to the cylindrical frame axis 12.

Secured to one end of the axle 15 is a first driven pulley 17 connected by a belt 18, which may be smooth or toothed, to a first drive pulley 19. The drive pulley 19 is driveably connected to a wheel drive servo-motor 20.

A second pulley 21, on the opposite of the wheel 10 to the first driven pulley 17, is mounted on a shaft (not shown) which passes through the axle 15 to roller drive means (not shown) within the wheel 10. The second driven pulley 21 is connected by a belt 22 to a second drive pulley 23 rotatably connected to a roller drive servo-motor 24.

The servo-motors 20, 24 are carried in a frame 16 mounted on the axle 15, The frame 16 also carries a number of batteries 25, a motor control system 26, an artifical intelligence system including one or more computer modules 27, a radio receiver 28 and antenna 29, and a load platform 30. The artificial intelligence system may contain for example, a level sensor or an inclinometer (not shown).

In use the vehicle will be held with the frame 16 substantially vertical above the axis 12 of the wheel 10 and the batteries switched on to drive the roller drive and wheel drive servo-motors 20, 24. Under the control of a predetermined programme of the computer modules 27 and motor control 26 the roller drive and wheel drive servo-motors 20, 24 will be driven at speeds such that the cylindrical frame 10 and rollers 13 rotate at speeds such that the frame 16 remains balanced vertically above the wheel 10.

When it is desired that the vehicle should move radio signals from a transmitter (not shown) will be communicated to the radio receiver 28 via the antenna 29, and the command system will drive the servo-motors 20, 24 at appropriate speeds to give the required motion with the frame 16 remaining balanced.

It will be realised that many alternative versions of this embodiment, within the scope of the invention, are possible.

For example, there are many alternative drive systems, the vehicle might carry a rider as well as, or instead of, the load platform 30, and the mountings of rollers 13 might be load sensing and connected to the drive system in such a way that only those rollers 13 bearing part of the weight of the vehicle will be rotated.

According to another embodiment of the invention (Figure 3) a bi-wheel vehicle has a frame 16 mounted on two axles 45 which lies on a common axis 46. At one end of each axle 45 is a wheel 47 driveable by a servo-motor 48 at the other end of the axle.

The frame carries batteries 25, a motor control system 26, an artificial intelligence system including one or more computers 27, a radio receiver 28 and antenna 29, and a load platform 30 similar to those described for the mono-wheel embodiment described above.

In use, the vehicle will be operated in the same way as the mono-wheel embodiment described above with reference to Figures 1 and 2.

In an alternative version of the bi-wheel embodiment of the invention (Figure 4) a horizontal servo joint 60 and an azimuth servo-joint 61 are incorporated in the frame 16. This allows the centre of gravity of the supported structure to be moved relative to the wheels 47, making it possible for one wheel 47 to be temporarily raised from the ground. Such a vehicle can therefore be adapted to climb stairs.

Manoeuvring of a bi-wheel vehicle to enable a load on the platform 30 to be positioned in any required orientation is simpler than for a mono-wheel vehicle, for which orientation in plan is complicated. However a mono-wheel vehicle might include in its frame an azimuth servo joint similar to that shown at 61 in Figure 4 (or even a horizontal servo joint 60).

The use of servo joints 60, 61 can be of assistance in loading and unloading of platform 30.

It will be realised that alternative versions of the bi-wheel vehicle are possible within the scope of the invention. For example, rather than the axles 45 lying on a common axis 46 they might lie on axes parallel but slightly separated.

Claims

What is claimed is: 1. A dynamically balanced vehicle including structure carried by a single wheel or by two wheels rotatable in parallel planes, driving means for driving the or each wheel, detection means for detecting the state of balance of the vehicle, and control means for controlling the driving means in such a way as to cause the vehicle to to remain stationary or to move in a desired direction with the structure balanced above the wheel or wheels.
2. A vehicle according to Claim 1 wherein the vehicle is a monowheel, the single wheel having a single frame rotatable about an axis and carrying at its circumference a plurality of rollers rotatable about parallel axes which are substantially not parallel to the frame axis, and the driving means being adapted to independently drive the frame and at least those rollers contacting a surface.
3. A vehicle as claimed in Claim 2 wherein all the rollers are driven.
4. A vehicle as claimed in Claim 2 or in Claim 3 wherein the driving means includes direct mechanical gearing.
5. A vehicle as claimed in Claim 2 or in Claim 3 wherein the driving means includes belts.
6. A vehicle as claimed in Claim 5 wherein the belts are toothed.
7. A vehicle as claimed in Claim 2 or in Claim 3 wherein the driving means includes a universal on a constant velocity joint.
8. A vehicle as claimed in Claim 2 or Claim 3 wherein the driving means includes a friction drive.
9. A vehicle as claimed in Claim 2 or in Claim 3 wherein the driving means includes a crank drive.
10. A vehicle as claimed in Claim 1 wherein the vehicle is a biwheel vehicle having two wheels rotatable in parallel planes.
11. A vehicle as claimed in Claim 10 wherein the wheels rotate about a common axis.
12. A vehicle as claimed in Claim 10 wherein the wheels rotate about axes which are parallel.
13. A vehicle as claimed in any one of Claims 1 to 12 wherein the driving means includes a drive unit in the form of a direct current servo motor.
14. A vehicle as claimed in any one of Claims 1 to 13 wherein the structure includes an azimuth servo joint.
15. A vehicle as claimed in any one of Claims 1 to 14 wherein the structure includes a horizontal servo joint.
16. A vehicle as claimed in any one of Claims 1 to 15 wherein the driving means, detection means and control means are carried in part or in whole by the structure.
17. A vehicle as claimed in any one of Claims 1 to 16 wherein the detection means includes a level sensor.
18. A vehicle as claimed in any one of Claims 1 to 16 wherein the detection means includes an inclinometer.

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19. A vehicle substantially as herein described.
20. A vehicle substantially as herein described with reference to Figures 1 and 2, or to Figures 3 and 4 of the accompanying drawings.