POWERED TRANSPORTATION DEVICE

FIELD OF THE INVENTION

This invention relates to the field of transportation devices, and in particular to powered transportation devices for transporting a load over a surface.

BACKGROUND OF THE INVENTION

Powered transportation devices, such as automobiles and boats, are widely known in the prior art. Such transportation devices are often configured to support and/or carry a load between a first and second location, over a surface such as a ground or water. Different forms of transportation device are often required to compromise between different desired characteristics for transportation devices, such as: flexibility of travel, speed of travel, comfort of travel energy expenditure required to travel and/or cost of travel.

By way of example, a helicopter provides a high flexibility and speed of travel (over short distances), but requires a significant amount of energy to operate and is typically an expensive way to transport a load. By way of contrast, a train provides a relatively cheap (per passenger) and fast method of travelling, at the expense of flexibility of travel, as a train can only move along a set path and between predetermined locations. On the other hand, a bicycle provides an extremely cheap and relatively flexible method of travelling, but is comparatively slow and uncomfortable.

There is therefore a desire to provide a transportation device that can provide a high flexibility, speed and comfort in travelling, whilst minimising a cost and energy expenditure required to travel.

SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to examples in accordance with an aspect of the invention, there is provided a powered transportation device for transporting a load over a surface, the powered transportation device comprising: a load support adapted to support a load of the powered transportation device; a drive member adapted to generate a drive force, for moving the load of the transportation device over the surface, via contact with the medium forming the surface; a drive control system adapted to control an operation of the drive member; one or more propulsion elements, each propulsion element being adapted to generate a propulsive force, a portion of which forms a positive or negative aerodynamic lift force for modifying an apparent weight of the powered transportation device; a lift control system adapted to control the operation of the one or more propulsion elements to thereby control the lift force generated by each propulsion element; and a balance control system adapted to adapted to be operable in at least one mode in which the balance control system maintains a fore-aft balance of the powered transportation device by controlling the operation of at least the drive control system.

The skilled person will appreciate that the medium forming the surface may be made of any material, e.g. soil, water, tarmac, concrete and so on, suitable for defining a surface over which a transportation device may travel. In particular, the medium forming the surface is formed of a non-gaseous substance. The drive member contacts (i.e. interacts with) the medium forming the surface, e.g. contacts the surface itself or contacts part of the medium located below the surface, in order to generate a drive force. Thus, the drive member may comprise, in various embodiments: a wheel, a track, a water propeller, a water paddle and so on. In other words, the drive member engages with a medium/material located at or below a surface over which the transportation device transports a load. In particular, the surface is formed from a solid or liquid (i.e. non-gaseous) material. The surface therefore defines a boundary between a gaseous substance (such as air) and a non-gaseous substance (such as water or ground).

Thus, the drive member contacts or is below the surface over which the transportation device travels, and the one or more propulsion elements are above this same surface. The drive member and the one or more propulsion elements are therefore offset from one another. The drive force generated by the drive member may be perpendicular to the lift force generated by the propulsion element(s).

The lift force generated by the propulsion element is an aerodynamic force (as opposed to hydrodynamic force). Thus, the propulsion element generates the propulsive force via contact/interaction with a gas such as air. It may be seen that the direction of the lift force is perpendicular to and offset from the direction of the drive force.

There is proposed a powered transportation device having a self-balancing mode in which a fore-aft balance (i.e. pitch) of the transportation device is maintained by at least a drive member (e.g. that operates via contact with a non-gaseous environment, such as water or a ground surface). Maintaining a fore-aft balance may comprise maintaining the transportation device, in particular the load support, in an upright position.

In other words, a pitch or fore-aft balance of a transportation device can be maintained by controlling a forward/rearward drive force. Thus, a load (such as a user) could be able to control a speed of the transportation device by attempting to lean the transportation device forward/backwards, e.g. by shifting their weight, so that the transportation device needs to accelerate to overcome the attempted lean to keep the transportation device upright.

Maintaining a fore-aft balance substantially increases a comfort of travel to a user, and also provides an intuitive method of controlling a speed of the transportation device, i.e. by shifting a position of the weight of the load. It should therefore be clear that, without the balance control system, the transportation device may tilt forwards and backwards (i.e. in fore and aft directions) about the drive member (if in contact with the medium forming the surface). In other words, the transportation device may be inherently unstable in a fore-and- aft direction (i.e. when unpowered can tilt in a fore and aft direction).

The lift force generated by the propulsion element(s) can be used to modify an apparent weight of the transportation device (i.e. the effective weight that the transportation device has on the medium forming the surface),

For example, a lift force may reduce an apparent weight of the transportation device to thereby provide a smoother ride to a user or load. In other words, the lift force may support a weight of the transportation device and/or the load thereof. In this way, the lift force can provides a cushioning affect to bumps or rough terrain, by reducing an effective weight of the transportation device.

Furthermore, use of one or more propulsion elements to reduce an apparent weight of the transportation devices means that more efficient drive members can be used. In particular, this enables the usage of more efficient drive members (e.g. motors requiring less torque) in order to power the load over the surface.

Alternatively, the lift force may alternatively act to increase an apparent weight of the transportation device (i.e. as a negative lift force may act in a direction of gravity), to improve traction and/or grip of the transportation device, which may increase an agility of the transportation device.

It will be clear that, when in contact with the medium forming the surface, the drive member at least partially supports the weight of the transportation device. Thus, supporting of the weight of the transportation device (and load) can be distributed between the drive member and the propulsion element(s) by controlling a lift force provided by the propulsion element(s).

Preferably, the drive member comprises a single wheel arrangement comprising one or more wheels lying along a single axis, so that the drive member is adapted to generate the drive force via contact with a ground surface.

Use of a single wheel arrangement enables the transportation device to traverse rough or steep terrain in comfort, and reduces a weight and cost of the transportation device. In particular, wheels and suspension arrangements for typical transportation devices add substantial bulk and cost to a transportation device. By using only a single wheel arrangement, and exploiting a self-balancing capability, this cost and weight can be avoided.

In other embodiments, the drive member is adapted to generate the drive force via contact with a liquid, such as (salt)water. Thus, the drive member may comprise an underwater propeller or a jet-pump.

This enables the transportation device to traverse over water. Fore-aft balance with respect to the water reduces a chance of the transportation device capsizing as well as improving a comfort to a user of the transportation device.

The balance control system may be operable in a dual control mode, in which the balance control system is adapted to maintain a fore-aft balance of the powered transportation device by controlling the operation of both the drive control system and the lift control system.

Use of the propulsion element(s) to contribute to maintaining a fore-aft balance of the transportation device can help maintain a safety of the transportation device. This is because a speed (provided by the drive member) required to balance a particular fore-aft tilt is reduced, as the propulsive force of the propulsion elements are able to contribute to the fore- aft balancing but not the speed.

Moreover, use of a propulsion element in controlling a fore-aft balance of the transportation device allows for a greater intended lean (in a fore-aft direction) to be counteracted. This increases a safety of the transportation device.

In some embodiments, the balance control system is (further) operable in a drive control only mode, in which the balance control system is adapted to maintain a fore-aft balance of the powered transportation device by controlling the operation of the drive control system only.

The dual control mode may act as an emergency mode, e.g. when the drive control only mode is not capable of maintaining a fore-aft balance. The balance control system may default to the drive control only mode and automatically switch to the dual control mode in response to detecting that the balance control system will be unable to maintain the fore-aft balance of the transportation device using the drive control system alone.

The drive control mode would be more power efficient than the dual control mode, as generation of a drive force is typically much more efficient than generation of a lift force.

Availability of the propulsion elements enables more efficient drive members to be used (e.g. smaller wheels or tyres), as the propulsion elements can be used as a brake or steering system to account for a loss of control of the drive member (where a likelihood of loss of control is typically reduced as a size of the drive member increases).

The balance control system may be further operable in a side-to-side balancing mode, in which the balance control system is adapted to: maintain a fore-aft balance of the powered transportation device by controlling the operation of at least the drive control system; and maintain a side-to-side balance of the powered transportation device by controlling the operation of the lift control system.

In particular, the one or more propulsion element may be adapted to be operable to adjust or modify a side-to-side (i.e. port-and-starboard or lateral) balance of the transportation device. Examples of suitable propulsion elements will be well known to the skilled person (e.g. angleable rotor blades).

In at least one embodiment, the transportation device comprises one or more proximity sensors, each proximity sensor being adapted to generate a proximity signal indicative of a presence of an entity in close proximity to a side of the powered transportation device, wherein, when operating in the side-to-side balancing mode, the balance control system is adapted to modify the lift force provided by the propulsion system based on the one or more proximity signals.

Preferably, the one or more propulsion elements comprise a fore-end propulsion element disposed towards a fore end of the powered transportation device and an aft-end propulsion element disposed towards an aft end of the powered transportation device.

Thus, there is at least one propulsion element disposed towards a front of the transportation device and at least one propulsion element disposes towards a rear of the transportation device. This enables increased control over the fore-aft balance of the transportation device.

The one or more propulsion elements may comprise at least one first side propulsion element disposed on a first side of the powered transportation device and at least one second side propulsion element disposed on a second, opposite side of the powered transportation device.

In some embodiments, the at least one first side propulsion element comprises at least two first side propulsion elements; and the at least one second side propulsion element comprises at least two second side propulsion elements.

For example, the at least one first side propulsion element may comprise: a first side fore-end propulsion element disposed towards a fore end of the powered transportation device; and a first side aft-end propulsion element disposed towards an aft-end of the powered transportation device. The at least one second side propulsion element may comprise: a second side fore-end propulsion element disposed towards a fore end of the powered transportation device; and a second side aft-end propulsion element disposed towards an aft-end of the powered transportation device

The one or more propulsion elements may be adapted to be capable of together generating a lift force sufficient to raise the powered transportation device from a surface. This does not exclude the possibility that any one of the propulsion elements may be capable of generating a lift force sufficient to raise the powered transportation device from the surface. Of course, if only a single propulsion element is present, then that propulsion element alone may be capable of generating a lift force sufficient to raise the power transportation device from a surface.

Embodiments of the invention are most effective when the propulsion elements can generate a lift force sufficient to raise or lift the transportation device from a ground. This allows the transportation device to, for example, float/fly over rough or terrain in/on which the drive member cannot generate a drive force (e.g. water for a ground-contacting drive member or vice-versa).

This increases a flexibility of travel, effectively providing the transportation device with the capabilities of a helicopter whilst minimising a cost of travel. In particular, surface- based travel (e.g. where a weight of the transportation device is at least partially supported via the drive member) is substantially more efficient for transporting a load, at the expense of flexibility and/or comfort of travel (e.g. due to traffic or restricted locations). By providing a transportation device able to transport the load via contact with a surface or via flying, flexible travel can be achieved without significantly increasing an expense of travel, as flying only need occur when it is not possible or efficient to travel over a surface. Thus, a hybrid- form of transportation is proposed with significant benefits. Enabling a transportation device to fly also increases a speed of travel, and obstacles can be readily overcome by flying over them. A flying transportation device also enables ‘straight-line’ travel to be provided, in which the transportation device can travel directly to a location without resorting to predetermined paths. This may be useful for solving the last- mile problem.

However, enabling a flying transportation device to travel via contact with a medium forming a surface increases an efficiency and eco-friendliness of the transportation device, as ground-based travel is more economic, less resource-intensive and quieter than air-based travel.

In some examples, when traveling between a first location and a second location, the transportation device may be adapted to fly from the first location to a nearest predetermined surface path (e.g. a motorway, highway or body of water), travel along the predetermined surface path via contact with the medium forming the surface, and subsequently fly from the predetermined surface path to the second location (e.g. when proximate to the second location).

Other examples of exploiting the capability of flying and travelling via contact with a medium forming a surface will be readily apparent to the skilled person, e.g. for use in transporting a load from one island to another.

The transportation device may further comprise a flight control system adapted to control the operation of the lift control system to thereby control a flight of the powered transportation device.

Preferably, the powered transportation device further comprises an obstacle detection system adapted to detect upcoming obstacles, wherein: in response to the obstacle detection system detecting an upcoming obstacle, the flight control system generates an avoidance command for the lift control system; and in response to the avoidance command, the lift control system controls the operation of the one or more propulsion elements so as to avoid the upcoming obstacle.

The avoidance command may be a lift command, so that the lift control system controls the operation of the one or more propulsion elements to fly over/under the identified obstacles. In other examples, the avoidance command is a steering command, so that the transportation device is steered around the identified obstacle.

In examples, the transportation device may be adapted to travel over a surface via contact with the medium forming the surface until an obstacle is encountered. The transportation device may then fly over the obstacle, and thereafter continue to travel via contact with the medium forming the surface. This increases a speed and flexibility of travel, and reduces time spent waiting for an obstacle to clear or otherwise circumventing the obstacle.

Preferably, the upcoming obstacles detected by the obstacle detection system comprises upcoming vehicular traffic. In other examples, the upcoming obstacles comprises turbulence, clouds, fog, waves, environmental hazards, potholes, trees, mountains, hills, surface, ground and so on.

The balance control system may be operable in a flight mode, in which the balance control system suspends an operation of the drive control system. This can ensure that the drive control system does not attempt to balance the transportation device when the transportation device is not in contact with the medium forming the surface (i.e. when the drive member is unable to generate a drive force).

The powered transportation device may further comprise a surface detection unit adapted to detect whether the powered transportation device is in contact with the surface over which the load is transported. Preferably, the balance control system is adapted to switch mode based on a determination of the surface detection unit. It has been identified that it may be more energy efficient to control a mode of the balance control system based on whether the device is flying, taking off, landing or travelling via contact with the medium forming the surface. This means that the control modes that use of the drive control system may, for example, be automatically deactivated or switched away from when the transportation device is flying.

In some embodiments, the transportation device further comprises one or more pivoting members adapted to pivot one or more propulsion element to thereby control a direction of the propulsive force output by the one or more propulsion elements.

The powered transportation device may further comprise a retracting mechanism adapted to controllably position the drive member between: a retracted position, wherein the drive member is a first distance from the load support; and a deployed position, wherein the drive member is a second, greater distance from the load support.

Preferably, the drive member is connected to the load support by a connecting element having a length of at least lm, and even more preferably at least l.5m. Thus, the load support may be distanced from the single wheel arrangement by at least lm. Even more preferably, the single wheel arrangement (and preferably the drive control system) is distanced from other components of the transportation device by the connecting element. This means that the bulk of the transportation device is able to travel over obstacles on a surface, whilst the wheel arrangement can weave between the obstacles with a high degree of agility. This allows the transportation device to travel through narrow gaps between obstacles at a surface (e.g. between traffic) or to cut through non-solid obstacles (e.g. waves), thereby increasing a travelling speed of the transportation device over terrain having obstacles (e.g. vehicular traffic or waves) thereon.

The connecting element may be adjustable in height, e.g. between a retracted position and a deployed position, e.g. using a telescopic member. This means that the connecting element may be extended (e.g. to travel between obstacles) whilst maintaining contact with the medium forming the surface (e.g. to support a weight of the transportation device) or retracting, to maximise a ground effect and thereby efficiency of the transportation device.

The connecting element may further comprise a unidirectional actuator adapted to controllably provide a lift force to raise the powered transportation device from the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which:

Figure 1 illustrates a transportation device according to a first embodiment of the invention;

Figures 2 illustrates a propulsion element for a transportation device;

Figures 3 to 5 illustrates different configurations for a transportation device according to an embodiment;

Figure 6 illustrates a transportation device according to a second embodiment of the invention;

Figure 7 illustrates a transportation device according to a third embodiment of the invention;

Figures 8 and 9 illustrates a transportation device according to a fourth embodiment of the invention;

Figures 10 and 11 illustrate alternative buoyancy aids for a transportation device according to the fourth embodiment;

Figure 12 illustrates a transportation device according to an embodiment of the invention;

Figure 13 illustrates electronic components for a transportation device according to an embodiment of the invention; and Figures 14 and 15 illustrate a transportation device according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

According to a concept of the invention, there is proposed a transportation device for transporting a load over a surface, for example, formed from water or earth. The transportation device comprises a propulsion element that generates an aerodynamic lift force and a drive element that generates a drive force via contact with the material forming the surface. A fore-aft balance of the transportation device can be maintained by appropriate control of at least the drive force.

Embodiments are at least partly based on the realisation that a propulsion element, that generates a lift force, can modify an apparent weight of a transportation device and can, in embodiments, contribute to maintaining a fore-aft balance of a self-balancing transportation device. In particular, it has been recognised that one or more propulsion elements can both support a weight of a powered device and help control a balance of a self- balancing device.

Illustrative embodiments may, for example, be employed in the transportation of people and/or other loads.

Analogously to an aircraft, the transportation devices described herein are each treated as having three, perpendicular axes running through the centre of mass of the transportation device: a longitudinal axis (running from a fore end to an aft end); a normal axis (running from top to bottom); and a lateral axis (running from side-to-side).

As used herein, a“lift force” F _L IFT refers to a force parallel to the normal axis of a transportation device. A“thrust force” F _TH R refers to a force parallel to the direction of the longitudinal axis of a transportation device. A“lateral force” FLAT refers to a force parallel to the direction of the lateral axis. Any of these forces may be positive or negative.

An“overall lift force” refers to the combination of all lift forces acting on the transportation device. An“overall thrust force” refers to the combination of all thrust forces acting on the transportation device. An“overall lateral force” refers to the combination of all lateral forces acting on the transportation device.

When the longitudinal axis and the lateral axis of the transportation device are both parallel to a surface, a direction of a lift force is in a same axis as a gravitational force. A positive overall lift force would attempt to raise the transportation device from a surface. A negative overall lift force would attempt to push the transportation device into the surface. A lift force can therefore support a weight of the transportation device.

A“drive force” refers to a force that moves a transportation device forwards and backwards. Thus, a drive force is parallel to a direction of the longitudinal axis of the transportation device. The drive force may, in some examples, be considered a thrust force generated via contact with a solid/liquid medium.

Figures 1 to 8 describe embodiments of a transportation device in which the drive member is formed from a single wheel arrangement. Thus, the transportation device described in these Figures travels over a surface. Figures 9 to 12 describe embodiments of a transportation device in which the drive member is instead formed from a water propeller. Thus, the transportation device described in these Figures travels over a water surface.

Both forms of transportation device (i.e. ground-based or water-based) operate on similar principles, and the hereafter described propulsion elements for use with such a device may be adapted for use with either form of transportation device.

Figure 1 illustrates a transportation device 1 according to a first embodiment of the invention. The transportation device 1 is adapted to transport a load 10 over a surface 11, here a ground surface such as a road, dirt, earth and the like.

The powered transportation device 1 comprises a load support 2, a drive member 3 and one or more propulsion elements 5, 6. A chassis 8 or framework may connect the different components of the transportation device together.

The load support 2 is adapted to support a load 10 thereon. The load support 2 may, as illustrated, comprise a seat and/or handle for supporting a user or load. In other examples, the load support may comprise a container, platform, strapping system, clip and so on. The chassis 8 may also help support the load, and can therefore be considered to be part of the load support 2.

The drive member 3 is formed of a single wheel arrangement 3. The single wheel arrangement 3 comprises one or more wheels lying along a single axis. That is, each wheel of the single wheel arrangement 3 lie next to one another side-by-side so that the remainder of the transportation device is able to tilt about the single wheel arrangement 3. The single wheel arrangement 3 is adapted to support a weight of the transportation device 1 (including the load).

The single wheel arrangement 3 can generate a drive force for moving the transportation device forwards and backwards over the surface 11. Thus, the single wheel arrangement 3, via contact with the medium (e.g. the road, earth and so on) forming the ground surface, can generate a drive force. The operation of the single wheel arrangement 3 is controlled by a drive control system (not shown). The drive control system is adapted to control at least a rotation speed and rotation direction of the single wheel arrangement 3. By way of example, the drive control system may comprise one or more motors for driving each wheel of the wheel arrangement forwards and backwards over the surface 11. The drive control system may control the operation of the wheel arrangement in response to a drive control signal. The drive control system therefore controls the drive force generated by the single wheel arrangement.

The single wheel arrangement 3 is vertically offset from each one or more propulsion element 5, 6.

Each of the one or more propulsion elements 5, 6 is adapted to generate a propulsive force F _P. At least a portion (e.g. substantially all) of the propulsive force F _P forms a positive/negative aerodynamic lift force F _L IFT that acts on the powered transportation device. It would be well understood by the skilled person how a downward expulsion of a propellant (e.g. air or a chemical propellant) generates a corresponding upward lift force F _L IFT- Each propulsion system is thereby able to at least partially support a weight of the transportation device.

One exemplary propulsion element comprises a propeller (not shown) that, when rotated about its axis, generates a propulsive force that acts on the powered transportation device. However, other examples of suitable propulsion elements will be clear to the skilled person, such as a propulsive nozzle or chemical rocket. A propulsion element is any element capable of generating a propulsive force, and in particular any element capable of generating a propulsive force in air (e.g. rather than water).

The operation of each propulsion element 5, 6 is controlled by a lift control system (not shown). The lift control system may be adapted to control a magnitude and/or direction of the propulsive force, and thereby the magnitude of the lift force, generated by each propulsion system, e.g. by controlling characteristics of each propulsion element. The lift control system is adapted to control the operation of each propulsion system, for example, in response to a lift control signal.

If a propulsion element comprises a propeller, a lift control system may comprise, amongst other components, a motor, a swashplate, a gearbox and so on.

When the single wheel arrangement and each propulsion element are inactive, the transportation device may freely rotate in a fore-and-aft direction about the single wheel arrangement. The transportation device 1 comprises a balance control system 7 that is controls an operation of at least the single wheel arrangement (via the drive control system) and preferably each propulsion element (via the lift control system). The balance control system 7 may thereby generate a drive control signal and, optionally, a lift control signal.

The balance control system is adapted to be operable in at least one mode in which the balance control system maintains a fore-aft balance of the powered transportation device by controlling the operation of at least the drive control system

For example, the balance control system 7 is adapted to be operable in at least a dual control mode, in which the balance control system maintains and/or preserves a fore-aft balance of the transportation device 1 using the drive control system and the lift control system. In particular, the balance control system can use both the propulsion elements(s) 5, 6 and the single wheel arrangement 3 to maintain a level/pitch of the transportation device, and thereby the load.

In this way, the load (e.g. a user) is provided a way of controlling the acceleration or deceleration and/or speed of the self-balancing transportation device by shifting their weight about the load support (e.g. to attempt to lean the device forwards and backwards).

The balance control system 7 may comprise a gyroscope or accelerometer system that senses forward and backward tilt of the transportation device in relation to a surface. The balance control system uses this information to control/regulate the drive control system and lift control arrangement so as to keep the transportation device upright or level. Thus, in the dual control mode, a pitch of the transportation device is maintained.

By way of example, if a forward lean is detected, the drive control system may drive the single wheel arrangement forwards and a propulsion element positioned forward of the centre of mass of the transportation device may provide a positive lift force (acting against a gravitational force) to counteract the forward lean.

By way of another example, the drive control system may be driven forward to move the transportation device forwards, thereby inducing a lean in the transportation device (i.e. tilting the transportation device backwards). A propulsion element positioned rearward of the centre of mass of the transportation device may provide a positive lift force to counteract this rearward lean. Thus, the operation of the drive control system and the lift control system must be co-ordinated in order to maintain a fore-aft balance of the transportation device. In particular, a maximum forward speed (provided by the drive force) must be limited so that the drive control system cannot induce a lean in the transportation device that cannot be overcome by operating the propulsion element(s) using the lift control system. Thus, a user is provided with a multitude of ways of controlling the forward/rearward speed of the transportation device whilst maintaining the balance of the transportation device. This increases a flexibility and intuitiveness of driving the transportation device.

The balance control system may be operable in a drive control only mode, in which the balance control system 7 maintains a fore-aft balance of the transportation device by controlling the operation of the drive control system only. Thus, when operating in the drive control only mode, the balance control system does not rely on the at least one propulsion element to maintain a fore-aft balance of the transportation device.

In embodiments, in order to reduce an energy consumption, the balance control system may default to operating in the drive control only mode. The balance control system may switch to the dual control mode if it is unable to maintain a fore-aft balance using solely the drive control system (e.g. a weight or forward lean of the transportation device is too great for the drive control system alone to maintain the balance).

This dual control mode may thereby act as a safety or recovery mode to revert the transportation device to a level or upright position/orientation in the event of a dangerous situation (e.g. overlearning).

The propulsion elements 5, 6 may be adapted to together provide a sufficiently high lift force to raise the transportation device from a surface. In other words, the propulsion elements can be controlled so that the overall lift force provided by the combination of the propulsion elements overcomes a gravitational force acting on the transportation device. Thus, the propulsion elements may enable the transportation device to fly or move through the air.

The transportation device 1 may comprise a flight control system (not shown) adapted to control the operation of the propulsion elements to control a flight of the transportation device. The balance control system and the flight control system may be combined into a same control system for the transportation device (e.g. they may form modules of a same processing unit).

The flight control system is adapted to control characteristics of the propulsion elements, via the lift control system, in order to control the flight of the transportation device. By way of example, the flight control system may be adapted to adjust a thrust force or lateral force providing by the propulsion elements.

Thus, the flight control system may generate a lift control signal for controlling an operation of the lift control system. Suitable flight control systems would be well known to the skilled person. When operating in the dual control mode, the balance control system may override an operation of the flight control system to self-balance the transportation device further using the propulsion elements. Alternatively, the balance control system and the flight control system may work together to maintain a fore-aft balance of the transportation device (e.g. the flight control system acts as part of the balance control system).

The balance control system may also be operable in a flight control mode in which an operation of the drive control system (and thereby wheel arrangement) is suspended. In other words, the drive control system is deactivated when the balance control system is in a flight control mode, so that the wheel arrangement is not rotated by the drive control system. This helps save energy and reduces powered consumption by the transportation device during a flight.

It will be appreciated that, when the transportation device is flying, there is no need for the balance control system to maintain a fore-aft balance of the transportation device (i.e. using the drive control system). Accordingly, the operation of the drive control system may be suspended/paused during flight to reduce power consumption.

In the flight control mode, the drive control system may be completely deactivated (i.e. completely inoperable) or partially deactivated (e.g. continues to drive the wheel arrangement, but not to the extent of maintaining a fore-aft balance or drives the wheel arrangement forward and backwards). Only partially deactivating the drive control system may be advantageous to, for example, prevent the wheel(s) of the wheel arrangement freely rotating and causing unnecessary wear to the wheel arrangement. In examples, when in the flight control mode, the drive control system continues to drive the wheel (e.g. rock it backwards and forwards or slowly rotate it), which may help maintain lubrication of the wheel and prevent sticking (e.g. in wet weather).

The transportation device may comprise a surface detection unit (not shown) adapted to detect when the transportation device is in contact or in proximity to a surface (i.e. via the wheel arrangement). The surface detection unit may, for example, be incorporated into the wheel arrangement or comprise a dedicated proximity sensor.

The balance control system may switch to the flight control mode in response to the surface detection unit detecting that the transportation device is not in contact with a surface, i.e. it is flying. The balance control system may switch to a self-balancing mode, such as the drive control only mode, in response to the surface detection unit detecting that the transportation device is in contact with or is approaching a surface. Preferably, the balance control system switches away from the flight control mode when approaching a surface, whilst the transportation device is still flying. This will result in the drive control system being reactivated upon a landing approach. This advantageously ensures that the fore-aft balance of the transportation device is immediately maintained or reasserted upon landing.

Optionally, the transportation device 1 comprises an obstacle detection system 9 adapted to detect upcoming obstacles, wherein: in response to the obstacle detection system detecting an upcoming obstacle, the flight control system generates a lift command for the lift control system; and in response to the lift command, the lift control system controls the operation of the one or more propulsion elements so as to lift the powered transportation device over the upcoming obstacle.

The obstacle detection system 9 may be adapted to detect potential obstacles using an object detection system that utilizes, to directly detect an upcoming obstacle, one or more of: a LIDAR system, a RADAR system, a camera, a proximity sensor; and the like.

In other examples, the obstacle detection system is adapted to receive obstacle information or environment from an external source (e.g. obtain traffic reports or obstacle reports) to identify upcoming obstacles.

In particular, the obstacle detection system may comprise: a location obtaining device (e.g. a GPD navigation system) adapted to obtain a current location of the transportation device; and an obstacle information obtaining device adapted to obtain information about the locations of obstacles. The obstacle detection system may use the obtained current location and the obstacle information to detect whether there is an upcoming obstacle.

In yet other embodiments, an external device may track the location of the transportation device (e.g. using a vehicle tracker) and issue an alert to the transportation device when it detects that the transportation device is approaching a known obstacle. In other examples, nearby vehicles or transportation devices may transmit an alert indicating that there is an obstacle ahead. Thus, the obstacle detection system may be adapted to receive an alert from an external device indicating that there is a known obstacle ahead.

The upcoming obstacles detected by the obstacle detection system may comprise upcoming vehicular traffic, rough terrain, holes, bumps, kerbs, water, hills, construction work, buildings and so on.

The obstacles detection system 9 may also be adapted to detect when an obstacle has been overcome by the powered transportation device 1. Preferably, when the powered transportation device has overcome the upcoming obstacle, it returns to a surface. Thus, the flight control system may generate a descend command for the lift control signal in response to the obstacle detection system 9 indicating that the obstacle has been overcome.

In this way, the transportation device may fly over obstacles in its path, and return to a surface when the obstacle has been overcome. This increases a travelling speed of the transportation device (e.g. as it may move in a straight line over obstacles), whilst minimising an energy expenditure of the transportation device (as less energy is spent driving along a surface than flying).

In at least one embodiment, the transportation device 1 comprises a retracting mechanism (not shown) adapted to move the wheel arrangement 3 between a deployed configuration and a retracted configuration.

The wheel arrangement may be more proximate to the remainder of the transportation device when in the retracted configuration than when in the deployed configuration. The retracting mechanism may thereby cause the wheel arrangement to act analogously to landing gear.

The wheel arrangement may thereby be retracted during a flight of the transportation device to reduce air resistance or drag, and may be deployed when the transportation device is driven along a surface. The movement between the deployed configuration and the retracted configuration may be automatic (e.g. in response to a surface detection unit) or manual (e.g. activated by a switch or mechanically moved using a handle).

In some examples, the retracting mechanism may be adapted to move the wheel arrangement from a deployed configuration to a retracted configuration in response to an obstacle. By way of example, if the wheel arrangement contacts an obstacle, the retracting mechanism may move the wheel arrangement from the deployed configuration to a retracted configuration.

The retracting mechanism may comprise a telescoping member (which telescopes in and out to move from the retracted configuration to the deployed configuration), and/or a pivoting member (which pivots the wheel arrangement from the retracted configuration to the deployed configuration).

The powered transportation device 1 may also comprise an energy storage system (not shown), such as a battery, for providing power to the various components of the transportation device. Each propulsion element 5, 6 may be replaced by a respective plurality of propulsion elements, according to various configurations of the transportation device.

The transportation device 1 may comprise an enclosure (not shown) adapted to enclose a load supported on the load support 2. This may, for example, comprise a cockpit for a user or the like.

The propulsion elements may be driven by a mix of electrically driven propulsion elements and petrol/fuel driven propulsion elements. For example, a first one or more propulsion elements may be driven by or comprise a combustion drive turbine or a jet engine, and a second one or more propulsion element may be driven by an electric motor. In some examples, the fuel engines may be adapted to drive a propulsion element and generate electricity for powering another propulsion element(s).

This enables a transportation device to have quickly-engaging propulsion element(s), as electric motors require very little start-up time, combined with high-efficiency and longevity propulsion element(s), as turbines are able to provide long-lasting and efficient propulsive force but have a relatively slow-start up time.

In some examples, the transportation device 1 may comprise additional propulsion elements adapted to generate a lift force on the transportation device. In some embodiments, the additional propulsion elements may be independent of the balance control system (i.e. they may not be controllable by the balance control system to maintain and/or control a fore- aft balance of the transportation device).

In particular examples, the additional propulsion elements are directly driven by a turbine engine, with the other propulsion elements being driven by an electric motor. The turbine engine(s) may generate the electricity for powering the electric motor. Thus, the turbine engines may provide a majority of the lift force, with the electric motor driven propulsion elements contributing to maintain a fore-aft balance of the transportation device.

Figure 2 illustrates a propulsion element 5, 6 for use in any herein described transportation device.

The propulsion element 5, 6 comprises a propeller 21 formed of one or more rotor blades 22 connected to a central rotatable element 23. In the illustrated example, the propeller comprises four separate rotor blades.

The central rotatable element 23 rotates about an axis, thereby inducing a rotating of the one or more rotor blades 22. A rotation of the rotor blades 22 causes a propulsive force to be output by the propulsion element. A direction and/or magnitude of the propulsive force generated by a particular propulsion element 22 may be controlled by controlling one or more characteristics of the propulsion element 5, 6 (e.g. speed of rotation of the central rotatable element or angle of attack of the blades 22). Other characteristics of the propulsion element may be controlled, such as a direction of propulsive force output by the propulsive element.

In particular, the balance control system or the flight control system may be able to adjust characteristics of the propeller in order to maintain a fore-aft balance of the transportation device. Thus, the balance control system may, for example, define a speed of rotation of the propeller or an angle of attack of the blades.

The propulsion element 5, 6 may further comprise a control element 24 (for defining an operation of the propeller 21), and a support 25 for connection the propulsion element 5, 6 to the remainder of the transportation device.

The propeller 21 may comprise a protective grill (not shown) covering the one or more blades, to prevent a user or load coming into contact with the one or more blades, thereby improving a safety of the transportation device.

Figures 3 to 5 illustrate plan views of various configurations for a transportation device according to an embodiment. Any herein described transportation device, such as the later described water-based devices, may be adapted to follow the illustrated configurations.

Figure 3 illustrates a plan view of a first configuration of a transportation device 30 according to an embodiment of the invention.

The at least one propulsion element of the transportation device 30 comprises a fore- end propulsion element 35 disposed towards a fore end (i.e. front) of the transportation device and an aft-end propulsion element 36 disposed towards an aft end (i.e. rear) of the transportation device 30.

The fore-end propulsion element 35 is positioned in front of a centre of mass of the transportation device and a rear-end propulsion element 36 is positioned behind a centre of mass of the transportation device.

It will be clear that a fore-aft balance of the transportation device 30 can be modified or maintained using the propulsion elements 35, 36.

By way of example, a positive lift force (e.g. a force pushing away from a surface) provided by the fore-end propulsion element 35 will cause the transportation device to tilt backwards (e.g. to counteract a forward tilt) and a negative lift force (i.e. a force pulling towards a surface) provided by the fore-end propulsion element will cause the transportation device to tilt forward (e.g. to counteract a rearward tilt). Figure 4 illustrates a plan view of a second configuration of a transportation device 40 according to an embodiment of the invention.

The transportation device 40 comprises two fore-end propulsion elements 45, 46 and a single aft-end propulsion element 47.

The fore-end propulsion elements 45, 46 are disposed on respective sides of the transportation device 40. The fore-end propulsion elements 45, 46 thereby act as a first side propulsion element 45 disposed on a first side of the powered transportation device and a second side propulsion element 46 disposed on a second, opposite side of the powered transportation device.

Thus, there is a first side fore-end propulsion element 45 disposed towards a fore end of the powered transportation device; and a second side fore-end propulsion element 46 also disposed towards a fore end of the powered transportation device; and

Here, the term‘side’ is used to refer to a left /right hand side of the transportation device (i.e. perpendicular to a fore-aft direction), or a port/starboard side of the transportation device. Thus, if an imaginary line is drawn along the fore-aft direction of the transportation device, a first side propulsion element 45 lies on one side of this line, and a second side propulsion element 46 lies on the other side of this line.

A (first or second) side propulsion element 45, 46 will, when providing a propulsive force having a lift force component, attempt to rotate the transportation device about its longitudinal axis, i.e. attempt to perform a roll.

If both first and second side propulsion elements are activated, and provide a same lift force in a same direction, the transportation device will not roll.

If the first side propulsion element(s) provides a greater lift force than the second side propulsion element(s), but where both lift forces are in a same direction, the transportation device will perform a roll in which the first side of the transportation device rises and the second side of the transportation device lowers.

Thus, by controlling the propulsive force, and thereby lift force, output by the first and second side propulsion elements, a roll or side-to-side balance of the transportation device can be controlled.

Where the transportation device 40 comprises at least one first side propulsion element and at least one second side propulsion element, the balance control system may be operable in a side-to-side balancing mode.

In the side-to-side balancing mode, the balance control system is adapted to maintain a fore-aft balance of the powered transportation device by controlling the operation of at least the drive control system; and maintain a side-to-side balance of the powered transportation device by controlling the operation of at least the lift control system.

Thus, a side-to-side balance (or‘roll’) of the transportation device may be controlled by defining the operation of the propulsion elements, e.g. number of active propulsion elements, magnitude of propulsive force output by propulsive elements, angle of the propulsive force and so on.

Of course, when operating in the side-to-side balancing mode, the balance control system may also use the lift control system to maintain a fore-aft balance of the transportation device.

Figure 5 illustrates a plan view of a third configuration of a transportation device 50 according to an embodiment of the invention.

The transportation device 50 comprises two fore-end propulsion elements 55, 56 and two aft-end propulsion elements 57, 58.

The fore-end propulsion elements 55, 56 are formed of a first fore-end propulsion element 55 and a second fore-end propulsion element 56, disposed on respective sides of the transportation device 50. Similarly, the aft-end propulsion elements 57, 58 are formed of a first aft-end propulsion element 57 and a second aft-end propulsion element 58 that are disposed on respective sides of the transportation device 50.

The first fore-end propulsion element 55 and the first aft-end propulsion element 57 also act as first side propulsion elements, e.g. disposed on a left-hand side of the transportation device 50. The second fore-end propulsion element 56 and the second aft-end propulsion element 58 also act as second side propulsion elements, e.g. disposed on a right- hand side of the transportation device.

Other configurations for a transportation device are envisaged. In one configuration, the transportation device comprises two aft-end propulsion elements (disposed on either side) and a single fore-end propulsion element. In another configuration, the transportation device comprises at least one fore-end propulsion element, at least one aft-end propulsion element and at least one central propulsion element (disposed between the fore-end propulsion element and the aft-end propulsion element). By way of example, the propulsion element may comprise no fewer than six propulsion elements, e.g. no fewer than eight propulsion elements, optionally wherein the propulsion elements are evenly split between both sides.

Figure 6 illustrates a transportation device 60 according to a second embodiment of the invention. The transportation device 60 according to the second embodiment differs from the transportation device 10 according to the first embodiment in that the rear-end propulsion element(s) 65 is vertically offset from the fore-end propulsion element(s) 66.

Preferably, the rear end propulsion element(s) 66 is disposed above the user support.

In some embodiments, the rear end propulsion element(s) 66 contributes a majority (>50%, e.g. >65%) of the lift force for the transportation device. In particular, where the propulsion elements are able to provide sufficient lift force to raise the transportation device from the ground, the rear end propulsion element may contribute a majority (e.g. (>50%, e.g. >65%), e.g. >75%) of the lift force required to raise the transportation from the ground.

In even more preferable embodiments, the rear end propulsion element(s) is able to provide sufficient lift force by itself to raise the transportation device from the surface. In such embodiments the fore-end elements may control a direction of the transportation device by controlling at least a side-to-side lean.

In embodiments where the rear end propulsion element contributes a majority of the lift force, a centre of mass of the transportation device is located more proximate to the rear end propulsion element(s) 66 then the fore-end propulsion element(s) 65. This helps prevent the transportation device from undesirably tipping due to a large moment provided by the rear-end propulsion element.

Preferably, the transportation device 60 is configured in accordance with the second configuration (as illustrated in Figure 4). This provides a simple

Figure 7 illustrates a transportation device 70 according to a third embodiment of the invention.

The transportation device 70 according to the third embodiment differs from the transportation device 10 according to the first/second embodiment in that the transportation device 70 further comprises a connecting element 71 connecting the wheel arrangement to the remainder of the transportation device (e.g. to the chassis 9 or framework).

The length x of the connecting element 71 is preferably no less than lm, and preferably no less than l.5m. This allows the transportation device to weave in-between traffic or other obstacles, as the substantial part of the transportation device (e.g. the user support and the propulsion elements) are disposed a suitably lengthy distance from the surface.

In particular, the wheel arrangement may be disposed at least lm from the user support and the at least one propulsion element, and preferably no less than l.5m. The connecting element may be adjustable in height, so that the transportation device can move between travelling close to a surface and travelling more distant from the surface. Travelling close to a ground surface increases a ground effect, thereby making the propulsion elements more effective, whereas travelling more distant from the ground surface enables the transportation device to weave around/through obstacles whilst maintaining contact with a surface (e.g. to ensure the driving member can continue to drive the transportation device). Thus, a connecting element may be extend (e.g. up to a length x). This concept may be realised using a telescopic member.

As illustrated in Figure 7, the transportation device may comprise a jet engine 79 adapted to generate electricity for the transportation device (e.g. to power the propulsion element(s) and/or the drive control system, or other electronics of the transportation device).

The jet engine may, for example, comprise a gas turbine. In embodiments, the jet engine contributes to an overall lift force of the transportation device. In particular, an exhaust of the jet engine may output a propulsive force that acts as a lift force. The lift control system may be adapted to control an amount of propulsive force output by the jet engine to thereby control a lift force generated by the jet engine 79.

The jet engine may be employed in any herein described transportation device, and is not limited to use in this particular embodiment. However, it is preferable that the transportation device comprises a connecting element 71 having a length of at least lm, in order to safely position the jet engine a distance away from a load (e.g. prevent a load coming into contact with the jet engine.

The single wheel arrangement of any of the above-described embodiments may be replaced by a liquid-contacting or liquid-interacting drive member such as a propeller.

In some embodiments, not illustrated, the connecting element may further comprise a unidirectional actuator adapted to controllably provide a lift force to raise the powered transportation device from the surface.

The unidirectional actuator may comprise, for example, a hydraulic/pneumatic piston or spring (for pressing the drive member against a ground surface), a (water)jet and so on. The unidirectional actuator is adapted to enable the transportation device to“jump”, by being activating to thereby cause the transportation device to move upwards. Thus, the unidirectional actuator provides a sudden or“step” lift force.

This may be used to supplement, as herein described, a“jumping” ability of the transportation device (e.g. over obstacles or the like). This unidirectional actuator may be implemented in any transportation device herein described, and adapted accordingly. Figure 8 illustrates an embodiment of a transportation device 80 having such a liquid- contacting drive member 83. The transportation device is adapted for travel over a water surface 89. The medium forming the water surface is water, which extends downwardly from the water surface. Thus, the medium forming the surface 89 here comprises material below the (water) surface.

The powered transportation device 80 comprises a load support 82, a drive member 83 and one or more propulsion elements 85, 86. A chassis 88 or framework may connect the different components of the transportation device together.

The load support 83 and propulsion element(s) 85, 86 may be formed and operated in a similar manner to the transportation devices previously described. Thus, the propulsion element(s) are controlled by a lift control system (not shown).

The drive member 83 is adapted to generate a drive force via contact with water, which forms the surface 89. The drive member may contact the water a substantial distance (e.g. >lm) below the surface. Preferably, the drive member is adapted, when in use, to not extend above the surface of the water.

In this way, the drive member 83 may be entirely below the surface over which the load is transported, and the propulsion elements 85, 86 may be entirely above the surface over which the load is transported.

The drive member 83 here comprises a propeller, such as a screw propeller, adapted to generate a drive force. The operation of the drive member (e.g. rotation speed) is controlled by a drive control system (not shown). Other embodiments for the drive member will be readily apparent to the skilled person, such as paddles, pump-jets and the like. It will be clear that the transportation device 80 is able to pitch forwards and backwards with respect to the surface 89.

As before, the transportation device 80 comprises a balance control system 87 adapted to maintain a fore-aft balance of the transportation device by controlling an operation of the drive member 83 (via the drive control system) and optionally the propulsion element(s) 85, 86 (via the lift control system).

By maintain a fore-aft balance of the transportation device, a comfort of travelling over the water surface may be substantially increased.

The transportation device 80 may further comprise a buoyancy aid 84, e.g. connecting the drive member 83 to the chassis 88. The buoyancy aid is adapted to at least partially support the weight of the transportation device (and load 10). This reduces an amount of energy required to keep the transportation device upright and to keep the load 10 above the surface.

The buoyancy aid 84 may be shaped so as to minimise a surface area exposed to a moving fluid (i.e. minimise the surface of the buoyancy aid that faces or is normal to a direction of travel).

Thus, the width of the buoyancy aid 84 may be narrow comparative to a width of the transportation device (e.g. less than 10% of the width of the transportation device). Here, the width means a distance from one side (e.g. port) to another side (e.g. starboard) of the transportation device. The buoyancy aid 84 may be hydrodynamically designed to minimise exposure. Thus, the buoyancy aid may be streamlined.

In embodiments, such as illustrated in Figure 8, the buoyancy aid may be shaped like a torpedo. In other words, the buoyancy aid may be substantially cylindrical, with a pointed tip, i.e. cigar-shaped.

The transportation device 80 may comprise a connecting element 81 connecting the drive member 83 to the remainder of the transportation device (e.g. to the chassis 9 or framework), optionally via the buoyancy element. The connecting element is adapted to maintain the chassis of the transportation device above the water surface.

The length x of the connecting element 81 is preferably no less than lm, and preferably no less than l.5m. This allows for the drive element 83 to be positioned well below the water surface 89, so that the drive element 83 can provide a highly efficiency drive (e.g. without encountering waves or surface/floating debris).

Similarly, the buoyancy element may be designed so that the drive element is located more than lm below the water surface 89. This increases an efficacy of the drive member, as it will be in full contact with the water and does not need to come into contact with waves or surface debris.

Figure 9 is a frontal or cross-sectional view of the transportation device 80, for illustrating the shape of the buoyancy aid 84. As illustrated in Figure 9, the buoyancy aid 84 may be substantially cylindrical with a pointed tip.

This provides a highly efficiency buoyancy aid, which causes minimal drag on the transportation device when it moves forwards/backwards.

Figure 9 also illustrates how the transportation device 80 may comprise first side propulsion element(s) and second side propulsion element(s), as previously described.

Figures 10 and 11 illustrates an alternative buoyancy aid 94 for the transportation device 80. The buoyancy aid 94 is fish-shaped. In other words, it is formed in an elongate shape, having a height greater than its width, and a length longer than its height. The buoyancy aid tapers to a point in the direction of travel (i.e. the width of the buoyancy aid is narrower at the fore-end of the transportation device at a centre of the transportation device. This improves a hydrodynamic structure of the buoyancy aid, improving an efficiency of the transportation device.

Figure 12 illustrates a cross-sectional view of a transportation device 100 according to an embodiment.

The transportation device 100 differs from previously described transportation devices in that it further comprises a pivoting member 109 A, 109B adapted to pivot the propulsion element 105, 106 to thereby control a direction of the propulsive force output by that propulsion element. In embodiments, each propulsion element 105, 106 is associated with a respective pivoting member 109 A, 109B.

The propulsive force F _P provided by each propulsion element(s) 105, 106 may be treated as comprising directional components perpendicular to one another. These components can be treated as separate forces: the lift force F _L IFT; the thrust force F _TH R; and the lateral force FLAT·

As illustrated, as previously explained, the lift force F _L IFT acts along a vertical axis, and the lateral force FLAT acts along a lateral axis. The thrust force (not shown) acts along a horizontal axis, which is directed into or out of the page.

The propulsive force may be represented by a force vector F _P :

By controlling a direction of the propulsive force output by the propulsion element, the relative proportion of the propulsive force contributing to the different components of the force can be controlled. In this way, a magnitude of each of the lift force, thrust force and lateral forces can be controlled by altering the direction of the propulsive force.

A lateral force FLAT, or lateral component, acting on the transportation device, and offset from the longitudinal axis, will cause the transportation device to tilt or roll about the wheel arrangement 3 about its longitudinal axis. Thus, by controlling a magnitude of a lateral force output by a propulsion element, a side-to-side balance of the transportation device can be controlled. This may be useful for implementing at least the side-to-side balancing mode. Thus, the balance control system may be adapted to control a direction of the propulsive force output by the propulsion element, via the pivoting member 109 A, in order to control a side-to-side lean of the transportation device.

The overall lateral force (being the combination of all lateral forces) can control a sideways movement of the transportation device.

A thrust force F _TH R acting on the transportation device, and offset from the lateral axis, will cause the transportation device to tilt or pitch about its lateral axis. Thus, by controlling a magnitude of the thrust force FTHR, a fore-aft balance of the transportation device can be controlled. This may be useful for implementing at least the dual control mode.

The overall thrust force (being the combination of all thrust forces, including a drive force generated by the driver member) can control a forward and rearward movement of the transportation device.

Preferably, the pivoting member is adapted to control at least what proportion of the propulsive force F _P contributes to the lift force F _L IFT and what proportion contributes to the lateral force FLAT, by controlling a direction of the propulsive force. In some examples, the pitch force may be maintained as substantially zero or substantially constant.

Thus, the pivoting member may be adapted to rotate the propulsion element about an axis lying parallel to a fore-aft direction of the transportation device. In this way, the propulsion element may rotate within a plane having an axis parallel to the fore-aft direction of the transportation device as its normal.

In this way, the pivoting member can control a magnitude of the lateral force lateral force FLAT adjusting a sideways lean or roll of the transportation device. In particular, as the propulsion element is angled further away from a surface, so a greater lateral force FLAT is provided to control the roll or sideways lean of the transportation device.

In other embodiments, the pivoting member is adapted to control at least what proportion of the propulsive force F _P contributes to the lift force F _L IFT and what proportion contributes to a thrust force F _TH R. In some examples, the lateral force FLAT may be kept substantially constant, e.g. zero.

Thus, the pivoting member may be adapted to rotate the propulsion element about an axis lying perpendicular to a fore-aft direction of the transportation device. In this way, the propulsion element may rotate within a plane having an axis perpendicular to the fore-aft direction of the transportation device as its normal.

In yet other embodiments, the pivoting member may be adapted to control a direction of the propulsive force in three-dimensions, so as to control the proportions of the propulsive force F _P that contribute to the lift force F _L IFT, sideways force FLAT and thrust force F _TH R respectively.

The powered transportation device 100 may comprise one or more proximity sensors 104 A, 104B. Each proximity sensor is adapted to generate a proximity signal indicative of a presence of an entity in close proximity to a side of the powered transportation device. When operating in the side-to-side balancing mode, the balance control system is adapted to modify the propulsive force provided by the propulsion system based on the one or more proximity signals

Thus, the proximity sensor(s) is adapted to determine when something is proximate or close to a side of the transportation device, and control the propulsive force based on the proximity of the entity to a side of the transportation device.

It has been recognised that an entity to the side of a transportation device may affect require changes to the propulsive force to counter-act a side-to-side lean of the transportation device. By way of example, an entity to a side may affect a side-to-side balance of the transportation device (e.g. the device is pulled towards the entity due to turbulence). This will affect

Thus, by monitoring the presence of an entity to the side of a transportation device, a side-to-side balance may be more effectively controlled.

Moreover, the presence of an entity to the side of a transportation device may affect the propulsive force generated by a propulsion element. In particular, if the propulsive force has a component of lateral force - the lateral force will differ depending upon the proximity of an entity to the side of the transportation device (analogously to a ground effect). This is due to the presence of the entity interrupting with downwash of a propulsion element.

Thus, maintaining the side-to-side balance of the transportation device may be provided more effectively by monitoring entities to a side of the transportation device to assess when a lateral force component of the propulsive force should be modified to maintain a side-to-side balance of the transportation device due at least to an expected change in the lateral force due to the presence of the entity to the side.

The propulsive force may be modified by changing its direction/angle and/or magnitude.

The proximity sensor(s) may comprise an infrared sensor, a LIDAR system, a RADAR system, a camera, a capacitive proximity sensor, a photoelectric sensor and so on. Thus, the proximity sensor comprises any sensor or device capable of determining whether there is an entity in close proximity to a side of the transportation device. Preferably, the proximity sensor is adapted to determine a distance between the entity and the transportation device, in order to enhance a control of the propulsive force.

Figure 13 is a block diagram of a processing module 110, and other electronic components, for a transportation device according to an embodiment.

The processing module comprises a balance control system 111 and a flight control system 112.

The balance control system, when operating in the first-self balancing mode, is adapted to control an operation of a drive control system 113 and the lift control system 114 in order to maintain a fore-aft balance of the transportation device. In particular, the balance control system may control a magnitude/direction of a propulsive force output by a propulsion element (via the lift control system 114) and either a magnitude/direction of a drive force output by the drive element (via the drive control system 113).

The balance control system may receive an input from an accelerometer 115 or gyrometer indicative of a change to a fore-aft balance in the system. In response to this input, the balance control system, when operating in the dual control mode, controls an operation of the drive control system and the lift control system to counteract the change in the fore-aft balance.

When operating in the drive control only mode, the balance control system only controls an operation of the drive control system - such that a self-balancing of the transportation device is only maintained by controlling a forward and rearward driving of the drive element.

The flight control system 112 is adapted to control an operation of the lift control system. The flight control system 112 can therefore control a direction and/or magnitude of the propulsive force output by the propulsion elements, in particular the lift force. In this way, the flight control system can control a flight (e.g. height/altitude, direction of travel and so on) of the transportation device.

The flight control system may work alongside the balance control system (e.g. receive signals from the balance control system) in order to, along with the balance control system, maintain a fore-aft balance of the transportation device using the drive control system and the lift control system. Thus, the balance control system may be adapted to control the lift control system via the flight control system.

The balance control system 112 may be adapted to stop maintaining a fore-aft balance of the transportation device when the transportation device is in flight. This may be required, as some transportation devices may require the device to be leaned in order to travel forward (e.g. analogously to a helicopter).

Thus, the balance control system 112 may be operable in a flight mode in which the operation of the drive control system 113 is suspended.

The processing module 110 may be adapted to receive a signal from a surface detection unit 116 adapted to detect whether the powered transportation device is in contact with the surface over which the load is transported. The mode and/or operation of the balance control system 112 may depend upon the signals received from the surface detection unit 116.

In particular, the balance control system may switch to the flight mode in response to the surface detection unit determining that the transportation device is not in contact with a surface.

The flight control system 112 may receive one or more user inputs Su, and control the lift control system 114 based on the one or more user inputs. By way of example, a user input may indicate that the user desires the transportation device to fly (e.g. ascend, descend, fly forwards or backwards etc.). The user input may be provided from a user, e.g. via joystick or other user input device, or from an autonomous driving system which acts as a driver of the transportation device.

The flight control system 112 may also be adapted to receive one or more signals from an obstacle detection unit 117. The obstacle detection unit is adapted to indicate when there is an upcoming obstacle, and may provide additional information about said obstacle (e.g. distance to obstacle, size of obstacle and so on). The flight control system may be adapted to control a flight of the transportation device based on the upcoming obstacle. Thus, the flight control system may automatically cause the transportation device to fly over upcoming obstacles.

In other examples, the obstacle detection unit 117 is adapted to alert a user of the transportation device of an upcoming obstacle. In response to a user input (e.g. confirmation to avoid obstacle), the flight control system may use information about the obstacle (obtained from the obstacle detection unit) to fly over the upcoming obstacle.

Whilst previously described embodiments include both a fore-end propulsion element and an aft-end propulsion element, in some embodiments the transportation device may comprise only a single propulsion element. In particular examples, a single propulsion element may be disposed above a location of the load (e.g. a user). In examples, the single propulsion element comprises a helicopter rotor system formed of at least one rotor blade. The pitch angle of the blades may be adjustable (e.g. by the balance control system via the lift control system) to adjust or control a fore-and-aft balance and/or a side-to-side balance of the transportation device. In particular, a cyclic control system may control the pitch angle of the at least one rotor blade during its cycle in order to control a tilt of the transportation device. Of course, such an example may further comprise a tail rotor to prevent spinning sideways. Such helicopter rotor systems are well known to the skilled person.

In other examples, a single propulsion element may comprise a helicopter rotor system formed of at least first and second rotor blades which rotate about a same axis, but preferably rotate in different directions (e.g. a first clockwise and a second anti-clockwise). Thus, the propulsion element may comprise coaxial rotors. In further such example, the blades may be controlled so as to enable a steering of the transportation device (e.g. using inertia of the blades). By way of example, a first blade may be rotated more quickly than the second blade, in order to steer the transportation device away from a rotation of the first blade. Methods of controlling the direction of the transportation device using helicopter rotors would be well known to the skilled person.

It will be appreciate that a propulsion element of any other transportation device herein described may be formed in a same manner as the previously described single propulsion elements. For example, a transportation device may comprise two or more propulsion elements each formed of a helicopter rotor system formed of at least one rotor blade.

There is also envisaged a steering self-balancing mode for the balance control system of any previously described embodiment. For operating in the steering self-balancing mode, the balance control system should be able to control a direction of the drive member (e.g. via a steering mechanism). Thus, the transportation device may comprise a steering mechanism adapted to control a direction of the drive member.

When operating in the steering self-balancing mode, the balance control system is adapted to maintain a fore-aft balance of the transportation device using at least the drive control system and maintain a side-to-side balance of the transportation device by controlling a drive direction of the wheel arrangement.

By way of example, if the balance control system detects that a transportation device is leaning towards a left side, the balance control system may turn the drive member to the left, so that the transportation device drives towards a left and overcomes the lean (thereby maintaining the transportation device in an upright position).

Embodiments may comprise the steering mechanism for controlling the travel direction of the transportation device. In other embodiments, the travel direction is controlled by leaning the transportation device (analogous to a motor cycle), or by controlling the direction of the propulsive force output by the propulsion element(s), analogously to a helicopter. Other methods of controlling a direction of travel will be readily apparent to the skilled person.

There is also envisaged a power-saving self-balancing mode, for being employed when each propulsion element comprises a propeller. In the power-saving self-balancing mode, the balance control system is adapted to maintain a fore-aft balance of the powered transportation device by controlling the operation of the drive control system only. The balance control system further controls the propeller(s) of the propulsion element(s) so that there speed of rotation depends upon a speed of the transportation device. In one embodiment, the propeller(s) are controlled so that the rotational speed of the propeller(s) is substantially equal (e.g. ±5% or ±1% difference) to the speed of the transportation device. This minimises a drag on the transportation device cause by the propeller(s), thereby providing a more efficient transportation device. Such an embodiment also reduces a start-up time for the propellers (e.g. if required to lift the transportation device or if the transportation device switches to the dual control mode).

There is also envisaged a lift control only-balancing mode, in which a fore-aft balance of the transportation device is maintained by controlling the operation of the lift control system only. Thus, in the lift control only-balancing mode, the drive control system may not contribute to maintain a fore-aft balance of the transportation device. In particular, the drive control system may be operated to control a forward/rearward speed of the transportation device and the lift control system may be controlled to maintain a fore-aft balance of the transportation device (i.e. that is attempted to be modified by the speed of the transportation device).

Figures 14 and 15 illustrate yet another embodiment of the invention, which comprises a powered transportation device 140 for transporting a load 10 over a surface.

The transportation device 140 comprises a load support 142 for supporting the load. Here, the load support comprises an enclosure for the load 10.

The transportation device 140 further comprises a drive member 143. The drive member may be embodied as in any previously described embodiment (e.g. operate via contact with a ground surface, such as using a wheel, or via a liquid, such as using a propeller).

The transportation device 140 further comprises a propulsion element 145 adapted to generate a propulsive force, a portion of which provides sufficient lift force to raise the transportation device from the surface (i.e. to fly). The propulsion element 145 here comprises coaxial rotors, but may instead comprise other propulsion elements (e.g. single rotor, pair of rotors etc.).

The propulsion element 145, load support 142 and drive member 143 are vertically aligned, so that they are stacked on top of one another. They need not be directly aligned with one another, e.g. one or more elements may be offset from a vertical axis.

In preferable embodiments, the drive member 143 is (controllably) rotatably connected to the load support. In particular, the transportation device may comprise a drive member angle control unit 146 adapted to control an angle of the control unit with respect to the load support. The drive member angle control unit 146 may be adapted to control a fore- aft angle and/or a side-to-side angle of the drive member 143 with respect to the load support.

Enabling control of the angle of the drive member 143 enables the drive member to act as a counter-weight to modify a lean angle of the transportation device, and thereby to control a direction of travel of the transportation device 140 (when in flight). In other words, controlling an angle of the drive member 143 enables a modification to be made to a centre of gravity of the transportation device to enable control over the angle of the transportation device, in particular the propulsion element.

Using control of the angle of the drive member to control the angle of the propulsion system avoids the need for cyclic control of the propulsion element. This avoids the need for potentially expensive control circuitry and/or equipment.

Thus, the drive member 143 can act as a counter- weight to modify a lean of the transportation device. For example, the drive member 143 may be controlled to have a fore- aft lean with respect to the load support in order to control a pitch of the transportation device. In another or further example, the drive member 143 may be controlled to have a particular side-to-side (e.g. in a port or starboard direction) in order to control a roll of the transportation device.

In preferable embodiments, the drive member is controllably rotatably in any direction with respect to the transportation device (i.e. movable from side-to-side as well as in a fore-aft direction). This effectively enables the angle of the drive member, with respect to the load support, to control a direction of the propulsive force provided by the propulsion element, and thereby a direction of travel of the transportation device.

In some further embodiments, the propulsion element 145 is freely rotatably connected to the load support 142, e.g. via a ball joint 147 or the like. This improves an agility of the transportation device in responding to a movement of the drive member

In particular, as the drive member is moved in a particular direction with respect to the load support, this will cause an equal and opposite movement in the load support. This causes the load support to rotate away from the propulsion element (due to inertia).

Thus, for example, if the drive member is rotated forward, so the propulsion element will be rotated forward with respect to the load support. This thereby increases an agility of the transportation device.

This feature is best illustrated by Figure 15, which illustrates a scenario in which the drive member has just been rotated forward, thereby effectively moving the load support backwards, and causing the propulsion element to also tip forward. This results in the transportation device moving forward (as the propulsion element will be tilted to thereby provide a thrust force to propel the transportation device forwards).

These embodiments are particularly useful when the transportation device is operable in a flight mode.

As used herein, the term“wheel” is used to refer to any ground contacting member suitable for driving a transportation device, such as a (caterpillar) track, roller, caster, wheel- and-axis, and so on.

The term“propeller” is used to refer to any element comprising one or more blades that, when rotated, generates a propulsive force on the transportation device. Here, the propulsive force comprises at least a lift force that supports a weight of the transportation device. The propeller may form part of a helicopter rotor, and may be formed of a rotor head and one or more blades. Optionally, the propeller also comprises a shaft.

Preferably, any of the herein described transportation devices are autonomous or self- driving. Thus, the transportation device may comprise an automatic navigation system, e.g. employing one or more external sensors, a satellite navigation system and/or a control system for controlling a speed and direction of the transportation device.

It is envisaged that future developments will comprise an artificial intelligence system adapted to monitor and predict the movement of matter in the vicinity of the transportation device (e.g. other traffic, airflow, upcoming terrain and so on), and be adapted to modify the operation of the drive control system and/or the lift control system based on a prediction of upcoming movement of matter. For example, an artificial intelligence system may be able to predict a change in air flow around a transportation device (e.g. due to upcoming obstacles) and adjust an operation of the lift control system and/or drive control system. In other words, there may be a monitoring system that effectively allows for active “airflow noise” cancellation, by predicting changes in upcoming airflow surrounding the transportation device.

Such an artificial intelligence system may comprise, for example, one or more cameras and a neural network system adapted to receive input from the camera and determine steps to take to account for predicted changes in the vicinity/environment of the transportation device (e.g. predicted changes in airflow/turbulence and so on). Suitable methods of adapting a neural network system would be known to the skilled person.

It is also envisaged that embodiments may comprise a traffic collision avoidance system (TCAS), adapted to communicate with other transportation devices to (automatically) avoid collisions with such devices. In embodiments, a permissible distance between transportation device may depend on the speed of the transportation devices, e.g. at a low speed the transportation devices are permitted to be closer. This is because slow moving transportation device have a reduced impact on air flow and turbulence that fast moving transportation devices, meaning that slow moving devices can get closer to one another without affecting the operation of the close transportation device.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.