ROAMING AIRBORNE EXPLORER SYSTEM

Abstract

An airborne device for surveillance of an enclosed area, comprising a platform having illuminating imaging devices, and an attached lighter than air balloon. A vertically aligned rotor provides additional lift, a rotor directed along the length of the platform provides forward and backward motion, and additional rotors aligned sideways steer and rotate the device. The rotors are driven by electric motors powered by an on-board battery. A vertically directed distance sensor measures and controls the hovering distance of the device from the roof. A reel of optical fiber is installed at the rear end of the platform, and the optical fiber unwinds from the reel and deploys behind the device as it moves forward. This optical fiber carries image data back to a monitor. The length of fiber deployed, combined with directional and accelerometer readings can be used to determine the absolute position of the device.

Claims

1. An airborne device for surveillance of an enclosed area, comprising: a platform having an illuminating device and an imaging device; and a lighter than air balloon attached to said platform, wherein said platform comprises: at least one motor driven rotor, having its axis vertically directed, such that it at least one motor driven rotor having its axis aligned along the longitudinal axis of said platform, such that it provides motion to said platform in the direction of said longitudinal axis; at least one other motor driven rotor having its axis in a generally horizontal plane at an angle to the longitudinal axis of said platform; a distance sensor directed such that it can measure the distance of said airborne device from the roof of said enclosed area; and a reel on which there is wound a length of optical fiber, said optical fiber receiving image data from said imaging device, and transmitting it to a remote monitor, wherein said reel is free to rotate such that as said platform moves in a forward direction, said reel rotates to enable said optical fiber to deploy in a backward direction from said reel.

2. An airborne device according to claim 1, wherein said platform further comprises a second sensor for determining the length of optical fiber deployed from said reel, such that the distance travelled by said airborne device can be determined.

3. An airborne device according to claim 2, wherein said second sensor is adapted to measure the number of rotations of said reel.

4. An airborne device according to claim 3, wherein said second sensor comprises an optical encoder or a slotted optical switch.

5. An airborne device according to any of previous claims 2 to 4, said platform further comprising additional sensors for determining the changes in orientation of said airborne device, such that, by combining information on said changes in orientation of said airborne device with the determined distance travelled by said airborne device, the absolute position of said airborne device can be determined.

6. An airborne device according to claim 5, wherein said additional sensors comprise at least one of a gyroscope, an accelerometer, and a digital compass.

7. An airborne device according to any of the previous claims, wherein said lighter than air balloon is of such a size and fill that it supplies the majority of the lift of said airborne device.

8. An airborne device according to any of the previous claims, wherein said lighter than air balloon is of such a size and fill that it supplies more than 90% of the lift of said airborne device.

9. An airborne device according to any of the previous claims, wherein said imaging device is a visible light camera or a FLIR camera.

10. An airborne device according to any of the previous claims, wherein the alignment of said imaging device is adjustable by means of a controlled pivoting device to enable imaging differently directed fields of view.

11. A method of determining the distance travelled by an airborne device, comprising: providing a reel of optical fiber at the rear end of said airborne device, said reel being freely rotatable; attaching a remote end of said optical fiber to a remote point; allowing said optical fiber to unravel from said reel as said airborne device moves away from said remote point; and measuring the number of rotations said reel performs during said motion, wherein said distance travelled by said airborne device is calculable from the number of rotations performed by said reel.

12. A method according to claim 11, wherein said measuring of the number of rotations said reel performs during said motion, is determined by use of an optical encoder operating on said reel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

[0045] FIG. 1 illustrates schematically a side elevation view of the payload platform of a roaming device according to an exemplary implementation of the systems of the present disclosure;

[0046] FIG. 2 is a schematic block diagram of one exemplary implementation of an electronics and control system suitable for the roaming device whose platform is shown in FIG. 1, and

[0047] FIG. 3 illustrates schematically the payload platform of FIG. 1, attached to its buoyancy balloon.

DETAILED DESCRIPTION

[0048] Reference is now made to FIG. 1, which illustrates schematically a side elevation view of the payload platform 9 of a roaming device according to an exemplary implementation of the systems of the present disclosure. The design of the roaming device shown in FIG. 1 is understood to be only one example of the manner in which the systems of this disclosure can be constructed, and is not intended to be limiting. Alternative geometric and mechanical arrangements can also be construed within the framework of this disclosure, so long as the intended operational functions of the roaming device are achieved.

[0049] The frame 10 of the payload platform 9 should be constructed of a lightweight material, such as a lightweight polymer or fiber construction, since the lighter the payload, the smaller is the size of the balloon required to support that payload. And, the smaller the size of the balloon, the smaller the dimensions of the passageways through which the roaming device can travel or roam. At the top edge of the frame, connectors 11 are provided in order to attach the frame 10 to its lighter-than-air balloon, as will be shown in FIG. 3 hereinbelow. Additional buoyancy, and control of the hovering height of the payload platform, is provided by a main buoyancy rotor 12, which is mounted with its rotor blades generally horizontal such that it can supply lift to the payload. This rotor is operated by an electric motor 13, as is the case with all the other rotors on the payload platform. The main forward motion rotor 14, is mounted with its axis in an almost horizontal orientation, and along the longitudinal axis of the payload platform, and is installed slightly aft the center of gravity of the platform. The slight upwards tilt given to this rotor is intended to compensate for reduction in lift by the lift rotor when the other rotors are operating and drain current from the main battery. The slight upward tilt of the main traction rotor provides an additional element of lift under those conditions. A pair of laterally directed rotors 15 are provided near the front and rear ends of the payload platform in order to provide the platform with yaw motion, which is used to enable the roaming device to rotate about itself to negotiate corners of the passage or space in which it is traveling. At the rear end of the frame, there is installed a freely rotating reel or spool 16, supported on a strut structure 17. The optical fiber 18 is wound on this reel 16, and as the roaming device moves forward through the passageway being surveilled or charted, the reel rotates freely as the optical fiber 18 is deployed out behind the moving device. A revolution-counting device, such as an optical encoder device and optical slotted switch assembly 19, or any other suitable device may be used to count the number of revolutions of the reel, which can be translated into the length of fiber unwound, so that the distance traveled by the device can be determined.

[0050] The surveillance payload is mounted in the forward part of the frame, with the imaging camera 1 mounted at the front, on a controlled rotatable gimbal or pivot 2, so that the direction of the field of view of the camera can be adjusted according to the requirements of the operator. A LED illumination device 3 is also shown mounted on the front end of the frame. The electronic circuit board or boards 4 are used both for processing the camera video output and for control of all of the motion and stability functions of the payload platform through the various rotors and sensors of the platform. These electronic circuits can also be used for hovering height control and for position and distance sensing, using inputs from the various sensors installed on the platform. In addition, the electronic circuit board may be used to convert the electronic video signal from the camera to and optical signal for transmission down the optical fiber 18. The height sensor 5, may conveniently be an optical height sensor, transmitting a modulated optical beam upwards, and determining the transit time for the pulses to return to the detector after reflection off the roof or ceiling. Finally, a lightweight battery 6 is installed for powering the electronic circuitry and the electric motors for the various rotors installed on the platform.

[0051] Reference is now made to FIG. 2, which illustrates a schematic block diagram of one exemplary implementation of an electronics and control system suitable for the roaming device shown in FIG. 1. The control of the device is performed in a central control microprocessor 20, advantageously implemented on a field-programmable gate array (FPGA), device mounted on the electronic circuit board 4 on the payload platform 9. The controller receives the inputs from the various sensors to define the position of the device. These inputs include the input from the height sensor 21, the input from the spool rotation sensor 22, which is used to determine the linear distance traveled, the input from the magnetometer orientation sensor or the magnetic compass 23 and the input from the MEMS accelerometer and gyroscope devices 24. The latter two sensors 23, 24, can be integrated into a single chip motion-tracking device. One such device, the MPU-9250 available from InvenSense Inc. of San Jose, Calif., USA, has 9-axis performance, and is currently available in a single lightweight package measuring no more than 3 mm.3 mm.1 mm., and including a 3-axis gyroscope, a 3-axis accelerometer, a 3-axis digital compass and an onboard microprocessor for processing the data from all of these functions to provide the orientation of the platform in all 3 dimensions.

[0052] The integrated output information regarding the device's path and position is output through the optical fiber to the monitor station 30, where the device operator can view the progress of the device. Based on this progress, and on any preplanned surveilling program, the device operator can input control commands 25 to the device, to instruct it to perform the required motion steps, and to instruct the forward illumination 27 to operate and to control the camera alignment 28. The video signals received by the imaging camera are input 31 to the controller, and are output to the monitor station 29 through the optical fiber, after conversion from digital and analog electronic signals to optical signals.

[0053] Finally, based on the distance, height and orientation inputs, and on the planned or instructed position, height and orientation of the device, electrical outputs are supplied to the motors of the various rotors, 26A, 26B, 26C, . . . 26N in order to achieve the desired results.

[0054] It is to be emphasized that the scheme outlined in FIG. 2 is only one possible arrangement for control of the roaming explorer device, and that it is possible to use alternative control schemes to achieve the objectives in the control of the device.

[0055] Reference is now made to FIG. 3, which illustrates schematically a payload platform 9 of the type shown in FIG. 1, attached to its buoyancy balloon 30. In order to support 90% of the weight of a payload platform of the type shown in FIGS. 1, and 45 cm in length, a balloon fill of helium of volume approximately 200 to 250 l. is required. Such a balloon can support a weight of approximately 120 g. One exemplary design of the 45 cm. payload platform of FIG. 1, weighs 130 gm. Therefore, using the above-described balloon, an additional lift of 10 gm. must be supplied by the lift rotor or rotors of the platform. This example illustrates the advantage to be obtained by the use of a buoyancy balloon in the present described systems. Whereas a conventional quadcopter of that lifting ability may have a battery capacity to keep it airborne for 10 to 15 minutes, use of a buoyancy balloon 30 as in the present disclosure, increases the flight time to over 30 minutes.

[0056] It is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.