GB2575075A - Drone apparatus - Google Patents

Abstract

A ground-based drone apparatus 101 comprises a wheel 102, a drive arrangement 103 disposed within and carried by the wheel 102 and operable to drive rotation of the wheel 102, and a balance arrangement 104 configured to generate a thrust force to balance the wheel 102 and maintain the apparatus 101 in an upright orientation. The thrust source may be propellers 105 which may be of variable pitch. I support leg arrangement 160 may be provided. The drone may carry a camera arrangement 189.

Description

DRONE APPARATUS

FIELD

This relates to a ground-based drone apparatus. In particular, this relates to a self-stabilising robotic wheel.

BACKGROUND

In recent years, significant advances have been made in the development and use of autonomous or semi-autonomous robotic vehicles, commonly known as drones.

Despite the advances, there are a number of significant barriers to the use of drones in a variety of applications.

For example, conventional aerial drones are often complex to control - in particular by inexperienced operators - and there have been a number of reported incidents involving collisions between drones and aircraft which have resulted in proposals for increased restrictions on the use of aerial drones in certain areas.

Conventional drones are also difficult to control and in some cases are unable to operate effectively in high winds or other inclement weather conditions.

The operational life of aerial drones is also limited due at least in part to the requirement for the drone to lift its own power pack.

One common application for drones is to provide a mount for a camera, since drones provide a cost effective and flexible alternative to other means of aerial photography. However, conventional aerial drones are often unable to fly safely near to ground level, such as under covered areas, and/or navigate obstacles, such as tree branches. Such obstacles make conventional aerial drones unsuitable for groundbased or near ground-based applications.

SUMMARY

According to a first aspect there is provided a ground-based drone apparatus, comprising:

a wheel;

a drive arrangement disposed within and carried by the wheel, the drive arrangement configured to drive rotation of the wheel; and a balance arrangement configured to generate a thrust force to balance the wheel and maintain the apparatus in an upright orientation.

The apparatus may take the form of a self-stabilising robotic wheel apparatus.

In use, the drive arrangement is operable to drive rotation of the wheel, while the balance arrangement maintains the balance of the wheel and thus maintains the apparatus in an upright orientation.

The drive arrangement may form part of a propulsion system of the apparatus.

The drive arrangement may be configured to engage and move the wheel so as to displace the orientation of the centre of mass of the apparatus, this displacement causing the wheel to rotate and propel the apparatus along the ground.

Alternatively or additionally, the drive arrangement may directly drive rotation of the wheel to propel the apparatus along the ground.

As described above, the balance arrangement may be configured to generate a thrust force to balance the wheel. The thrust force may be the result of fluid displacement caused by the balance arrangement.

The balance arrangement may, for example, comprise one or more variable pitch propellers.

The balance arrangement may comprise one or more ducted blade arrangements or the like.

The balance arrangement may comprise one or more variable pitch ducted blade arrangements or the like.

Embodiments of the apparatus provide a number of benefits over conventional drones. For example, the provision of a ground-based drone apparatus permits use of the apparatus under covered areas and/or in terrain where conventional aerial drones are unable to operate. The provision of a ground-based drone apparatus also obviates the requirement for the apparatus to lift its own power pack as in conventional aerial drones, permitting greater operational life to be achieved.

The apparatus may be operable autonomously, that is without direct user control.

Alternatively or additionally, the apparatus may be configured to be at least partially remotely controlled by a user. Where the apparatus is at least partially remotely controlled by a user, the apparatus comprises a wireless communication arrangement, such as radio frequency communication arrangement or the like.

The apparatus may comprise a support arrangement.

The support arrangement may be disposed within and carried by the wheel.

The support arrangement may be configured to support components of the apparatus within the wheel.

The drive arrangement may be disposed on the support arrangement.

The drive arrangement may be carried by the support arrangement.

The balance arrangement may be disposed on the support arrangement.

The balance arrangement may be carried by the support arrangement.

The support arrangement may comprise a framework.

The support arrangement may comprise one or more support struts.

The support arrangement may comprise of one or more flat plates with interlocking bolts.

The support arrangement may comprise an A-frame.

The support arrangement may comprise a chassis onto which components of the apparatus are mounted.

As described above, the apparatus comprises a wheel.

Beneficially, a ground-based drone apparatus utilising a single wheel provides an apparatus which occupies a relatively small footprint, such that the apparatus is capable of passing through relatively narrow spaces, facilitating the use of the apparatus in built up areas or for example wooded areas where conventional drones cannot operate effectively.

In particular embodiments, the wheel comprises a bicycle wheel.

The wheel may comprise an inflatable tyre.

The wheel may comprise a rim.

The tyre may be disposed on the rim.

The drive arrangement may be configured to engage the rim. In use, the drive arrangement may engage the rim to propel the apparatus along the ground.

As described above, the drive arrangement is disposed within and carried by the wheel, the drive arrangement configured to drive rotation of the wheel.

The drive arrangement may comprise a rotary drive.

The rotary drive may comprise a motor.

The motor may comprise an electric motor.

The motor may comprise a DC electric motor, such as a brushless DC electric motor.

The drive arrangement may comprise one or more drive wheel configured to engage the wheel, in particular the rim.

The drive arrangement may comprise a plurality of drive wheels, each configured to engage the wheel. In particular, but not exclusively, the drive arrangement may comprise three drive wheels.

The drive arrangement may be directly driven.

Alternatively, the drive arrangement may comprise a transmission system coupled between the rotary drive and the one or more drive wheel.

The transmission system of the drive arrangement may comprise a pulley drive arrangement.

The pulley drive arrangement may comprise one or more active pulley assemblies, that is, one or more pulley assembly which is actively driven to drive rotation of the wheel.

The pulley drive arrangement may comprise one or more passive pulley assembly, that is, one or more pulley assembly which is not actively driven.

In particular embodiments, the drive arrangement comprises one active pulley assembly and two passive pulley assemblies. Alternatively, the drive arrangement may comprise two active pulley assemblies and one passive pulley assembly.

As described above, the apparatus comprises a balance arrangement configured to balance the wheel.

It will be understood that references to balancing the wheel mean maintaining the wheel in an upright or substantially upright orientation relative to the ground.

The balancing arrangement may be configured to maintain the orientation of the wheel within a specified range of lean angle relative to vertical.

The balance arrangement may comprise a plurality of propellers. At least one of the propellers may comprise the variable pitch propeller.

In particular embodiments, the balance arrangement may comprise two variable pitch propellers.

The balance arrangement may comprise a plurality of ducted blade arrangements. At least one of the ducted blade arrangements may comprise the variable pitch ducted blade arrangement.

In particular embodiments, the balance arrangement may comprise two variable pitch ducted blade arrangements.

The balance arrangement may comprise a drive arrangement.

The drive arrangement of the balance arrangement may comprise a rotary drive.

The rotary drive may comprise a motor.

The motor may comprise an electric motor.

The motor may comprise a DC electric motor, such as a brushless DC electric motor.

The balance arrangement may be directly driven.

Alternatively, the balance arrangement may comprise a transmission system.

The transmission system may comprise a belt drive, chain drive, gear drive or the like.

The balance arrangement may comprise a pitching arrangement for varying the pitch of the one or more variable pitch propellers or ducted blade arrangements.

The pitching arrangement may comprise a linkage.

The pitching arrangement may comprise a push rod or the like.

The pitching arrangement may comprise one or more actuators.

The actuator may comprise one or more servo motors.

The apparatus may comprise a parking arrangement.

The parking arrangement may be disposed on the support arrangement.

The parking arrangement may be carried by the support arrangement.

The parking arrangement may comprise one or more legs.

The parking arrangement may comprise a plurality of legs.

In particular, but not exclusively, the parking arrangement may comprise four legs.

The leg or legs of the parking arrangement may be pivotable between a first, parked, position in which the legs engage the ground and a second, raised or running, position, and vice-versa.

In use, the parking arrangement may engage the ground to support the wheel when the apparatus is not in operation, or is otherwise stationary. The parking arrangement may be pivoted to the raised position during use. The apparatus may, however, be configured to deploy the parking arrangement while the wheel is moving, so as to act as an emergency brake.

The parking arrangement may comprise a drive for pivoting the leg or legs.

The drive may comprise an actuator.

The drive may comprise a motor.

In particular, but not exclusively, the drive may comprise a stepper motor.

The parking arrangement may be directly driven.

Alternatively, the parking arrangement may comprise a transmission system coupled between the drive and the leg or legs.

The apparatus may comprise a power supply.

The power supply may comprise an onboard power supply.

The power supply may be disposed on and carried by the support arrangement.

The power supply may take the form of a battery pack.

In particular, but not exclusively, the battery pack may comprise a LiPo battery pack.

The apparatus may be modular.

The apparatus may comprise a suspension arrangement.

The suspension system may comprise one or more spring, such as a compression spring.

The apparatus may comprise a housing or cover.

Beneficially, the provision of a housing or cover protects the components of the apparatus from damage and/or prevents users from accessing components of the apparatus. The housing may also protect users from injuring themselves.

The apparatus may comprise a control system.

The control system may be disposed onboard the apparatus.

The control system may be carried by the support arrangement.

The control system may comprise, or may be housed in, an electronics assembly or housing.

The control system may comprise a microprocessor unit.

The control system may comprise an electronic speed controller.

The control system may comprise an inertial measurement unit (IMU).

The inertial measurement unit (IMU) may comprise one or more sensors.

The inertial measurement unit (IMU) may comprise one or more gyro. In particular, the inertial measurement unit (IMU) may comprise three gyros, a first gyro configured to obtain data regarding the x-axis orientation of the wheel, a second gyro configured to obtain data regarding the y-axis orientation of the wheel, and a third gyro configured to obtain data regarding the z-axis orientation of the wheel.

The inertial measurement unit (IMU) may comprise one or more magnetometer. In particular, the inertial measurement unit (IMU) may comprise three magnetometers, a first magnetometer configured to obtain data regarding the x-axis orientation of the wheel, a second magnetometer configured to obtain data regarding the y-axis orientation of the wheel, and a third magnetometer configured to obtain data regarding the z-axis orientation of the wheel.

The inertial measurement unit (IMU) may comprise one or more accelerometer.

In particular, the inertial measurement unit (IMU) may comprise three accelerometers: a first accelerometer configured to obtain data regarding the x-axis motion of the wheel; a second accelerometer configured to obtain data regarding the yaxis motion of the wheel; and a third accelerometer configured to obtain data regarding the z-axis motion of the wheel.

The control system, in particular the inertial measurement unit (IMU), may comprise one or more high pass filter. The high pass filter is configured to pass signals having a frequency at or above a selected threshold while attenuating signals with lower frequencies. In use, sensor data from the one or more gyro may be passed through the high pass filter.

The control system, in particular the inertial measurement unit (IMU), may comprise one or more low pass filter. The low pass filter is configured to pass signals having a frequency at or below a selected threshold while attenuating signals with higher frequencies. In use, sensor data from the one or more accelerometer may be passed through the low pass filter.

The control system, in particular the inertial measurement unit (IMU), may comprise an Euler orientation algorithm.

The control system, in particular the inertial measurement unit (IMU), may comprise a complementary filter. In use, the complementary filter may combine the sensor data from the sensors to provide an output signal indicative of orientation of the apparatus.

The control system may comprise one or more controller.

The control system may comprise one or more PID controller.

For example, the control system may comprise a PID controller set including at least one of a roll PID controller, a pitch PID controller, and a yaw PID controller. In use, the controller set may receive the filtered sensor data output. The controller set may combine the filtered sensor data output with any user input control signals.

The control system may comprise an attitude controller. The attitude controller may receive the signal from the controller set.

The attitude controller may combine the signal from the controller set with data output from an RPM controller.

In use, the attitude controller may process the data from the controller set and the RPM controller and outputs instruction signal to one or more of the drive arrangement, drive arrangement of the balance arrangement, and drive of the pitching arrangement.

The control system may comprise a feedback loop from the rotary drive of the drive arrangement.

Beneficially, the feedback loop from the drive arrangement facilitates control of the rotational velocity of the rotary drive of the drive arrangement.

The apparatus may be configured for use in a number of applications. For example, the apparatus may be utilised in photographic applications; for the autonomous collection of sensory data; for the transportation of goods or equipment; may be utilised in military operations for investigative missions; and/or may be used as a recreational apparatus or toy.

In particular embodiments, the apparatus may be configured for use in photographic applications.

The apparatus may comprise a camera arrangement including a camera device.

Beneficially, embodiments of the apparatus may be used in photographic applications at or near ground level, in particular but not exclusively in environments and over terrain where aerial drone photography is not practical or possible.

The camera device may comprise a photographic camera, such as a digital photographic camera device.

Alternatively or additionally, the camera device may comprise a video camera, such as a digital video camera device.

Alternatively or additionally, the camera device may comprise a thermal imaging camera, such as an infra-red camera.

Alternatively or additionally, the camera device may comprise a night vision camera.

Alternatively or additionally, the apparatus may be configured for collection of sensory data.

The apparatus may comprise a sensory device for collection of the sensory data.

The apparatus may comprise a mount arrangement.

The mount arrangement may be configured for coupling to, or may form part of, a support arrangement of the apparatus.

The mount arrangement may comprise a stabilisation arm coupled to the support arrangement.

The mount arrangement may be configured to permit 360 degree rotation of the camera device and/or sensory device.

The mount arrangement may comprise a stabilisation mechanism.

The mount arrangement may comprise a gimbal.

It should be understood that the features defined above or below may be utilised, either alone or in combination with any other defined feature, in any other aspect or embodiment or to form a further aspect or embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a side view of a ground-based drone apparatus;

Figure 2 shows a side view of the apparatus shown in Figure 1, with cover removed;

Figure 3 shows an enlarged perspective view of the apparatus shown in Figures 1 and 2;

Figures 4, 5 and 6 show enlarged perspective views of components of the drive arrangement of the apparatus shown in Figures 1 to 3;

Figures 7, 8, 9 and 10 show enlarged perspective views of components of the balance arrangement of the apparatus shown in Figures 1 to 3;

Figures 11 and 12 show enlarged perspective views of the parking arrangement of the apparatus shown in Figures 1 to 3;

Figure 13 to 16 show the apparatus shown in Figures 1 to 3 in operation;

Figure 17 shows an enlarged perspective view of an electronics package of the apparatus shown in Figures 1 to 3;

Figures 18 and 19 show the control system architecture of the apparatus shown in Figures 1 to 3;

Figures 20, 21 and 22 show perspective views of a second ground-based drone apparatus;

Figure 23, 24 and 25 show enlarged perspective views of components of the camera arrangement of the apparatus shown in Figures 20 to 22; and

Figure 26 shows an alternative balancing arrangement for use in the apparatus shown in Figure 1 or Figure 20.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring first to Figures 1 and 2 of the accompanying drawings, there is shown a ground-based drone apparatus 1.

As shown in Figures 1 and 2, the apparatus 1 comprises a wheel 2, a drive arrangement 3 and a balance arrangement 4 comprising two variable pitch propellers 5a,5b. The drive arrangement 3 and balance arrangement 4 disposed within, and carried by, the wheel 2.

In use, the drive arrangement 3 is operable to drive rotation of the wheel 2 to propel the apparatus 1 along the ground G, while the balance arrangement 4 maintains the balance of the wheel 2 and thus maintains the apparatus 1 in an upright orientation.

Referring now also to Figure 3 of the accompanying drawings, there is shown an enlarged perspective view of the apparatus 1 shown in Figures 1 and 2.

As shown in Figure 3, the wheel 2 comprises an inflatable tyre 6 disposed around a profiled rim 7. In the illustrated apparatus 1, the wheel 2 takes the form a 26” (660.4 mm) bicycle wheel, although it will be recognised that the wheel 2 may be of any suitable size.

As described above, the drive arrangement 3, and balance arrangement 4 are disposed within and carried by the wheel 2, the drive arrangement 3 and balance arrangement 4 supported within the wheel 2 by a support arrangement 8. In the illustrated apparatus 1, the support arrangement 8 comprises a bracket 9 with struts 10 extending therefrom. Support struts 11 are also provided and generally define an Aframe.

Referring now also to Figures 4, 5 and 6 of the accompanying drawings, which show enlarged perspective views of parts of the drive arrangement 3, the drive arrangement 3 of the apparatus 1 comprises an active pulley wheel assembly 12 and two passive pulley wheel assemblies 13, 14.

Figure 4 shows an enlarged view of the active pulley wheel assembly 12. As shown, the active pulley wheel assembly 12 comprises a mount 15 having apertures 16 for the receiving the struts 10 of the support arrangement 8 and a padeye 17 for receiving one of the support struts 11. A motor 18 is disposed on the mount 15, the motor 18 in the illustrated apparatus 1 taking the form of a brushless DC electric motor. As shown in Figure 4, the active drive pulley assembly 12 comprises a first, drive, pulley 19 mounted on a drive shaft 20 of the motor 18 and a second, driven, pulley 21 mounted on an axle 22. The axle 22 extends through an aperture (not shown) in the mount 15 and supports a v-shaped grooved wheel 23. The active drive pulley assembly further comprises a drive belt 24 which is disposed over and between the first, drive, pulley 19 and the second, driven, pulley 21. As shown in Figure 4, the drive belt 24 passes over a bearing 25 which in the illustrated apparatus 10 takes the form of a ball bearing.

In use, the drive belt 24 transmits rotation of the motor 18 to the grooved wheel 23 which, in turn, drives rotation of the rim 7.

Figure 5 shows an enlarged view of the passive pulley wheel assembly 13. As shown in Figure 5, the passive pulley assembly 13 comprises a mount 26 having apertures 27 for receiving the struts 10 of the support arrangement 8 and a padeye 28 for receiving one of the support struts 11. The passive pulley assembly 13 further comprises a v-shaped grooved wheel 29 similar to the grooved wheel 23, the wheel 29 mounted on an axle 30.

Figure 6 shows an enlarged view of the passive pulley wheel assembly 14. As shown in Figure 6, the passive pulley assembly 14 comprises a mount 31 having apertures 32 for receiving the struts 10 of the support arrangement 8. The passive pulley assembly 14 further comprises a v-shaped grooved wheel 33 similar to the grooved wheels 23, 29, the wheel 33 mounted on an axle 34.

Referring now also to Figures 7, 8, 9 and 10 of the accompanying drawings, there are shown enlarged perspective views of components of the balance arrangement 4.

As shown in Figures 7 and 8, the balance arrangement 4 comprises a mount 35 having apertures 36 through which the struts 10 of the support arrangement 8 can pass. The mount 35 further comprises side apertures 37 (one of which is shown in Figure 8) into which are disposed hollow support arms 38 of the propellers 5a,5b.

As shown in Figures 7 and 8, the balance arrangement 4 further comprises two servo motors 39 which, in the illustrated apparatus 10 take the form of digital servo motors. An output shaft 40 from each servo motor 39 provides mounting for a servo arm 41, the servo arms 41 coupled to push rods 42 (shown in Figure 7) coupled to the propellers 5a,5b. A brace member 43 is disposed on and coupled to the servo motors 39 and has an aperture 44 through which one of the struts 10 of the support arrangement 8 is disposed.

Referring now also to Figures 9 and 10 of the accompanying drawings, the balance arrangement 4 further comprises a motor 45 for driving the propellers 5a,5b and which, in the illustrated apparatus 1, takes the form of a brushless DC electric motor. The motor 45 is coupled to the mount 35 and an output shaft (not shown) extends into the mount 35. As shown in Figure 7, two drive gears 46 are disposed on the output shaft of the motor 45, each drive gear 46 receiving a belt (not shown) which extends through the hollow support arms 38 and couples to a drive shaft 47 of each propeller 5a,5b.

Referring now in particular to Figures 9 and 10 of the accompanying drawings, each of the propellers 5a,5b comprises a blade arrangement comprising two blades 48a,48b. While in the illustrated apparatus 1, each propeller 5a,5b comprises two blades 48a,48b, it will be understood that the propellers 5a,5b may comprise any suitable number of blades. The blades 48a,48b are held within propeller attachment blocks 49a,49b by retention bolts 50a,50b. The propeller attachment blocks 49a,49b in turn are disposed on a rotor link 51 a,51b mounted on propeller drive shaft 52a, 52b rotationally mounted in a mount 53a,53b and secured using a collar 54a,54b. As shown in Figures 9 and 10, a tensioner 55a,55b is also provided.

In order to pivot the blades 48a,48b, the balance arrangement 4 further comprises a linkage 56a,56b coupled at one end to the rotor link 51 a,b and at the other end to a push rod connector 57a,57b coupled to the push rods 42.

Referring again to Figure 3 of the accompanying drawings, in addition to the drive arrangement 3 and balance arrangement 4, the apparatus 1 further comprises an onboard power supply in the form of battery pack 58, an onboard electronics assembly 59 and a parking leg assembly 60.

As shown in Figure 3, the battery pack 58 is suspended from the support struts 10 via straps 61 and in the illustrated apparatus 1 the battery pack 58 takes the form of a Lithium ion polymer (LiPO) battery pack.

Figures 11 and 12 of the accompanying drawings show enlarged perspective views of the parking leg assembly 60. As shown, the parking leg assembly 60 comprises a housing 62 comprising an upper bracket 63 having apertures 64 formed therein for coupling the parking assembly 60 to lower ends of the support struts 10 and a pair of leg support plates 65. Compression springs 66 are disposed around the struts 10 and form a suspension system for the parking leg assembly 60. In the illustrated apparatus 1, the parking leg assembly 60 comprises two pairs of legs 67, each pair of legs 67 mounted on the support plates 65. Each leg 67 terminates in a foot or stopper 68.

As shown most clearly in Figure 12, a motor 69 is disposed within the housing 62, the motor 66 in the illustrated apparatus 1 taking the form of an electric stepper motor. An output shaft 70 of the stepper motor 69 is coupled to a curved linkage member 71, the linkage member 71 operatively associated with the legs 67 so that rotation of the output shaft 70 pivots the legs 67 from a first, parked, position to a second, raised or running, position, and vice-versa. In some instances, the parking leg assembly 60 may be deployed during running to provide an emergency brake.

Referring now also to Figures 13 to 16 of the accompanying drawings, there is shown the apparatus 1 in different stages of operation.

Figure 13 shows the apparatus 1 in its parked configuration with the legs 67 deployed.

Figure 14 shows the apparatus 1 with legs 67 retracted and running in a first direction (to the left as shown).

Figure 15 shows the apparatus 1 with legs 67 retracted and running in a second direction (to the right as shown).

Figure 16 shows the apparatus 1 returned to its parked configuration with the legs 67 deployed.

Figure 17 of the accompanying drawings shows an enlarged perspective view of the electronics assembly 59 shown in Figure 3. Shown in Figure 17 are housing 72 for a microprocessor unit (not shown), an electronic speed controller 73 in the form of a VESC, a power connector 74, and microcontroller 75 in the form of a Teensy 3.6. As shown in Figure 17, the housing 72 comprises a clamp 76 for suspending the electronics assembly 59 from the support struts 10. Other components of the electronic assembly 59 are discussed below with reference to Figures 18 and 19 of the accompanying drawings.

Figures 18 and 19 of the accompanying drawings show the control system architecture 77 for controlling the operation of the apparatus 1.

In the illustrated apparatus 1, the control system architecture 77 comprises an inertial measurement unit (IMU) 78 comprising sensors in the form of gyros 79X,79Y,79Z, accelerometers 80X,80Y,80X and magnetometers 81X,81Y,81Z which, in use, provide sensor data as to the Χ,Υ,Ζ orientation and motion of the apparatus 1.

As shown in Figure 19, sensor data from the gyros 79X,79Y,79Z passes through a high pass filter 82, sensor data from the accelerometers 80X,80Y,80X passes through a low pass filter 83, and sensor data from the magnetometers 81X,81Y,81Z passes through a low pass filter 84. In use, the high pass filter 82 passes signals having a frequency at or above a selected threshold while attenuating signals with lower frequencies while the low pass filters 83,84 pass signals having a frequency at or below a selected threshold while attenuating signals with higher frequencies. The sensor data is combined via an Euler orientation algorithm 85 to provide an output signal indicative of orientation and motion of the apparatus 1.

As shown in Figure 18, the output from the IMU 78 is combined with user input control data U in a controller set 86. In the illustrated control system 77, the controller set 86 comprises a roll PID controller 86R, a pitch PID controller 86P, and a yaw PID controller 86Y. The output from the controller set 86 forms the input for attitude controller 87.

The attitude controller 87 processes the data from the controller set 86 and outputs instruction signals to the servo motors 39 and the motor 45 of the balance arrangement 4, e.g. via pulsed width modulation (PWM), in order to effect the appropriate fluid displacement and to the motor 18 of the drive arrangement 3, e.g. via a serial interface in the form of UART, in order to effect the appropriate centre of mass displacement. However, it will be recognised that other communication protocols may be used where appropriate.

As shown in Figure 18, the control system 77 further comprises a feedback loop to the IMU.

As described above, the apparatus 1 may be utilised in a variety of application and environments. Figures 20 and 21, for example, show front and rear perspective views of a ground based drone apparatus 101 according to a second embodiment, and which is configured for use in photographic applications.

The apparatus 101 is similar to the apparatus 1 and like components are represented by like reference numerals incremented by 100.

As in the apparatus 1, the apparatus 101 comprises a wheel 102, a drive arrangement 103 and a balance arrangement 104 comprising two variable pitch propeller assemblies 105, the drive arrangement 103 and balance arrangement 104 disposed within, and carried by, the wheel 102.

In use, the drive arrangement 103 is operable to drive rotation of the wheel 102 to propel the apparatus 101 along the ground G, while the balance arrangement 104 maintains the balance of the wheel 102 and thus maintains the apparatus 101 in an upright orientation.

As shown in Figures 20 and 21, the wheel 102 comprises an inflatable tyre 106 disposed around a profiled rim 107. In the illustrated apparatus 101, the wheel 102 takes the form a 26” (660.4 mm) bicycle wheel, although it will be recognised that the wheel 102 may be of any suitable size and construction.

As in the apparatus 1, in the apparatus 101 the drive arrangement 103 and balance arrangement 104 are disposed within and carried by the wheel 102, the drive arrangement 103 and balance arrangement 104 supported within the wheel 102 by a support arrangement 108. In the apparatus 101, however, the support arrangement 108 comprises a chassis 110 rather than the struts 10.

As in the apparatus 1, the drive arrangement 103 in the illustrated apparatus 101 takes the form of a pulley wheel drive comprising an active pulley wheel assembly 112 and two passive pulley wheel assemblies 113, 114.

Figure 22 shows an enlarged view of the active pulley wheel assembly 112 of the drive arrangement 103 of the apparatus 101 shown in Figures 20 and 21. As shown in Figure 22, the active pulley wheel assembly 112 comprises a motor 118 which is mounted within the chassis 110. In the illustrated apparatus 101, the motor 118 takes the form of a brushless DC electric motor. The active drive pulley assembly 112 further comprises a first, drive, pulley 119 which engages and which is driven by a bevel gear 188 mounted on a drive shaft (not shown) of the motor 118. The active drive pulley assembly 112 further comprises a drive belt 124 which is disposed between the first, drive, pulley 119 and a v-grooved wheel. In use, the drive belt 124 transmits rotation of the motor 118 to the grooved wheel 123 which, in turn, drives rotation of the rim 107.

Referring again to Figures 20 and 21, the balance arrangement 104 of the apparatus 101 comprises propellers 105 although in the apparatus 101 the propellers 105a, 105b are mounted on the framework 110. The balance arrangement 104 further comprises servo motors 139 which in the illustrated apparatus 110 take the form of digital servo motors.

The balance arrangement 104 further comprises a motor 145 for driving the propeller assemblies 105a, 105b and which, in the illustrated apparatus 101, takes the form of a brushless DC electric motor. Two drive gears (not shown) are disposed on the output shaft of the motor 145, each drive gear receiving a belt (not shown) which couples to a driven gear 185 disposed on the drive shaft 147 of each propeller 105.

In the apparatus 101, each of the propellers 105a,105b comprises a blade arrangement comprising two blades 148a,148b.

In order to pivot the blades 148a, 148b, the balance arrangement 104 further comprises a push rod connector and linkage arrangement similar to that described above with reference to the apparatus 1.

As in the apparatus 1, the apparatus 101 further comprises an onboard power supply in the form of battery pack 158, an onboard electronics assembly 159. As in the apparatus 1, the battery pack 158 takes the form of a Lithium ion polymer (LiPO) battery. The electronics assembly 159 is identical to the assembly 159.

It can be seen that the battery pack 158 and onboard electronics assembly 159 are disposed at a lower position in the apparatus 101 than in the apparatus 1, this beneficially providing a lower centre of gravity of the apparatus 101.

As in the apparatus 1, the apparatus 101 also comprises a parking leg assembly 160 comprising two pairs of legs 167. In use, the legs 167 are pivotable between a first, running, position and a second, parked, position, and vice-versa.

As described above, the apparatus 101 is configured for use in photographic applications and as shown in Figure 20, and referring now also to Figures 23, 24 and 25 of the accompanying drawings, the apparatus 101 comprises a camera arrangement 189.

As shown, the camera arrangement 189 comprises a stabilisation arm 190 which is coupled to the chassis 110 and which extends over the top of the wheel 102. A mount 191 is disposed on the stabilisation arm 190 via anti-vibration mounts 192, the anti-vibration mounts 192 in the illustrated apparatus 101 taking the form of rubber balls. The mount 191 supports a gimbal 193. A camera base 194 with counterweight 195 is coupled to the gimbal 193 and supports camera device 196. The camera arrangement 189 provides stability in both pitch and roll.

Various modifications may be made to the apparatus without departing from the scope of the invention.

For example, Figure 26 shows an alternative balance arrangement 204. The balance arrangement 204 is similar to the balance arrangements 4, 104 and like components are represented by like reference signs incremented by 200.

As shown in Figure 26, the balance arrangement 204 comprises a motor 245 for driving propellers 205a,205b, the motor 245 taking the form of a brushless DC electric motor. The motor 245 is coupled to mount 235. The balance arrangement 204 comprises a single driven gear 246 disposed on the output shaft of the motor 245, the drive gear 246 receiving a belt (not shown) which extends through the hollow support arms 238 and couples to a drive shaft 247 of each propeller 205a,205b.

Each of the propellers 205a,205b comprises a blade arrangement comprising two blades 248a,248b. In order to pivot the blades 248a,248b, the balance arrangement 204 further comprises a linkage 253a,b coupled to push rods 242, the push rods 242a,242b operated by servo motors 239 in a similar manner to the servo motors 39,139 described above.

As described above, the apparatus 1, 101 provide a number of benefits over conventional drone apparatus. For example, the provision of a ground-based drone apparatus permits use of the apparatus under covered areas and/or in terrain where conventional aerial drones are unable to operate. The provision of a ground-based drone apparatus also obviates the requirement for the apparatus to lift its own power pack as in conventional aerial drones, permitting greater operational life to be achieved.

Claims (25)

1. A ground-based drone apparatus, comprising:

a wheel;

a drive arrangement disposed within and carried by the wheel, the drive arrangement configured to drive rotation of the wheel; and a balance arrangement configured to generate a thrust force to balance the wheel and maintain the apparatus in an upright orientation.

2. The apparatus of claim 1, wherein the apparatus takes the form of a selfstabilising robotic wheel apparatus.

3. The apparatus of claim 1 or 2, wherein the drive arrangement is configured to engage and move the wheel so as to displace the orientation of the centre of mass of the apparatus, this displacement causing the wheel to rotate and propel the apparatus along the ground.

4. The apparatus of claim 1, 2 or 3, wherein the balance arrangement is configured to generate a fluid displacement to cause the thrust force to balance the wheel.

5. The apparatus of any preceding claim, wherein the balance arrangement comprises one or more variable pitch propellers or variable pitch ducted blade arrangements.

6. The apparatus of any preceding claim, comprising a support arrangement disposed within and carried by the wheel.

7. The apparatus of claim 6, wherein the drive arrangement is disposed on and/or carried by the support arrangement.

8. The apparatus of claim 6 or 7, wherein the balance arrangement is disposed on and/or carried by the support arrangement.

9. The apparatus of any preceding claim, wherein the wheel comprises a rim and wherein the drive arrangement is configured to engage the rim.

10. The apparatus of any preceding claim, wherein the drive arrangement comprises a rotary drive, such as an electric motor.

11. The apparatus of any preceding claim, wherein the drive arrangement comprises one or more drive wheel configured to engage the wheel.

12. The apparatus of claim 11, when dependent on claim 10, wherein the drive arrangement comprises a transmission system coupled between the rotary drive and the one or more drive wheel.

13. The apparatus of claim 12, wherein the transmission system of the drive arrangement comprises a pulley drive arrangement.

14. The apparatus of any preceding claim, wherein the balancing arrangement is configured to maintain the orientation of the wheel within a specified range of lean angle relative to vertical.

15. The apparatus of any preceding claim, wherein the balance arrangement comprises a drive arrangement.

16. The apparatus of claim 15, wherein the drive arrangement of the balance arrangement comprises a rotary drive, such as an electric motor.

17. The apparatus of any preceding claim, wherein the balance arrangement comprises a transmission system.

18. The apparatus of any preceding claim, when dependent on claim 5, wherein the balance arrangement comprises a pitching arrangement for varying the pitch of the one or more variable pitch propellers or variable pitch ducted blade arrangements.

19. The apparatus of claim 18, wherein the pitching arrangement comprises:

a linkage;

a push rod; and one or more actuator, such as a servo motor.

20. The apparatus of any preceding claim, comprising a parking arrangement comprising a plurality of legs pivotable between a first, parked, position in which the legs engage the ground and a second, raised or running, position, and vice-versa.

21. The apparatus of any preceding claim, comprising a power supply disposed on and/or carried by the support arrangement.

22. The apparatus of any preceding claim, comprising a mount arrangement.

23. The apparatus of claim 23, wherein the mount arrangement comprises at least one of:

a stabilisation arm; and a stabilisation mechanism, such as a gimbal.

24. The apparatus of any preceding claim, comprising a camera device, wherein the camera device comprises at least one of: a digital photographic camera device; a digital video camera device; a thermal imaging camera, such as an infrared camera; and a night vision camera.

25. The apparatus of any preceding claim, comprising a sensory device for collecting sensory data.