WO2018090943A1

WO2018090943A1 - Unmanned aerial vehicle for underwater photographing

Info

Publication number: WO2018090943A1
Application number: PCT/CN2017/111264
Authority: WO
Inventors: 阮桂
Original assignee: 捷西迪（广州）光学科技有限公司
Priority date: 2016-11-18
Filing date: 2017-11-16
Publication date: 2018-05-24
Also published as: CN206265327U

Abstract

An unmanned aerial vehicle for an underwater photographing comprises a fuselage (200), a photographing device (300), a height measurement device (290), a driving device (260), an attitude control device, and a photographing device balance detection device. When the unmanned aerial vehicle moves on a water level, the photographing device balance detection device detects that an optical axis of the photographing device (300) does not form a right angle with a photographed object, and the attitude control device on the photographing device (300) changes an angle between the photographing device (300) and the unmanned aerial vehicle by means of the driving device (260), so as to compensate the change of the optical axis of a lens module, thereby ensuring a good photographing visual angle.

Description

Unmanned aerial vehicle for underwater shooting

Technical field

The present invention relates to the field of unmanned aircraft technology, and more particularly to an unmanned aerial vehicle for underwater shooting.

Background technique

At present, photography techniques using fisheye lenses and unmanned aerial vehicles equipped with cameras have been known to the public. When a camera is mounted on a drone, a wide-angle lens is usually selected for shooting, in order to obtain a large amount of information in a single shot. With a fisheye lens, you can use a camera to take pictures of the surrounding image. In the past, unmanned aerial photography was limited to aerial photography and it was impossible to capture images in water.

To take underwater images with unmanned aerial vehicles, at least consider the following questions: First, how to accurately measure the distance between the unmanned aircraft and the water surface, so that the lens is submerged in the water while keeping the body position in the air, so that the unmanned Under the flight, the aircraft can achieve underwater photography. The above flight state includes not only the hovering state but also the state of moving in the horizontal direction.

Secondly, when the unmanned aircraft adopting the rotor structure moves in the horizontal direction, the body will be tilted. How to offset the optical axis variation of the photographic device caused by the tilt of the body is a difficult point. Depending on the direction of the optical axis, the common photographic devices mounted on unmanned aircraft can be divided into two types: one is that the optical axis direction is substantially parallel to the horizontal plane, and the other is that the optical axis direction is substantially perpendicular to the horizontal plane. Since the angle of the optical axis is different from the angle of movement of the unmanned aircraft on the horizontal plane, the above two types of photographic devices also have large differences in how to compensate for the movement of the optical axis caused by the movement of the fuselage. Specifically, the latter is more sensitive to the change in the angle of the optical axis, but it is possible to approximately ignore the change in the overall center of gravity of the drone and the photographing device due to the zoom. When an imaging device equipped with a fisheye lens module is mounted on a drone, in order to avoid being blocked by the body, an arrangement in which the optical axis direction of the fisheye lens module is substantially perpendicular to the horizontal plane is generally selected. Therefore, how to solve the problem that the optical axis of the photographing device caused by the tilt of the body is quickly and accurately compensated when the optical axis is perpendicular to the horizontal plane is a problem to be solved.

Summary of the invention

The technical problem to be solved by the present invention is to provide an unmanned aerial vehicle for underwater shooting that automatically adjusts the shooting angle of view.

A technical solution adopted to solve the above technical problem: an unmanned aircraft for underwater shooting, including a body; a photographing device disposed under the fuselage, the photographing device including a lens module; a height measuring device, It is disposed at the bottom of the fuselage for measuring the distance between the fuselage and the water surface below; the driving device is disposed on the body or the photographing device for changing the angle of the photographing device relative to the body; the posture control device, It is disposed on the body or the photographing device for controlling the driving device; and the photographing device balance detecting device is disposed on the photographing device for detecting the angle of deflection between the optical axis direction of the lens module and the horizontal plane.

Further, a body balance detecting device is further disposed on the body for detecting a deflection angle between the body and the horizontal plane; and the memory stores the deflection of the optical axis of the body or the lens module relative to the horizontal plane The correspondence between the angle and the height of the photographic device in which the body or the lens module is located with respect to the water surface; and the control unit for controlling and monitoring the operating state of the unmanned aircraft.

Further, the airframe further includes at least one rotor arm extending outwardly relative to the body in a horizontal direction, the height measuring device being disposed at a bottom end of the rotor arm.

Further, the photographic device balance detecting device is an electronic level or a gyroscope, and the lens surface of the lens module is coated with a waterproof or hydrophilic coating.

Further, the lens module of the photographing device is a fisheye lens module with a viewing angle greater than or equal to 180 degrees, the photographing device is provided with a water level measuring instrument and/or a buoy, and the photographing device is provided with a direction and a lens module. The light axis direction is the same as the fill light for underwater illumination.

Further, the height measuring device is a phase ultrasonic height measuring instrument.

Further, a bottom of the fuselage is provided with a support arm for connecting the photographing device, and the driving device is disposed on the support arm, and the support arm is provided with a telescopic mechanism that extends or shortens its length.

The beneficial effect: when the drone moves on the horizontal plane, the photographing device balance detecting device detects that the optical axis of the photographing device is not at a right angle relationship with the photographing object, and the posture control device on the photographing device changes the angle between the photographing device and the unmanned aircraft through the driving device. In order to compensate for the variation of the optical axis of the lens module, a good viewing angle is ensured.

DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

1 is a schematic structural view of an embodiment of the present invention;

2 is a schematic view of moving in a horizontal direction according to an embodiment of the present invention.

detailed description

1 is a schematic structural view of an unmanned aircraft according to an embodiment of the present invention. The unmanned aircraft may be a small aircraft that is operated in the air for external control. The unmanned aircraft has a body 200 and a photographing device 300 loaded by the body 200. However, the unmanned aircraft may also be a semi-autonomous aircraft that has built-in GPS, is programmed in advance with a control program related to the route, or may be a fully autonomous aircraft that does not require user operation, and the unmanned aircraft is loaded with a battery.

The user can use the operating device to send commands to the unmanned aircraft through wireless communication, thereby controlling the take-off, air flight, and landing of the unmanned aircraft. In addition, the photographing device 300 mounted on the unmanned aircraft can also be operated.

Exemplarily, the photographing device 300 employs a camera having a wide angle fisheye lens with a viewing angle of 180 degrees or more, and the photographing device 300 can be moved along the optical axis of the lens loaded by the body 200, and is transmitted from the photographing device 300 to the operation. The image signal of the device can be continuously transmitted from the power of the unmanned aircraft from on to off, or can be transmitted according to an instruction given by the user to the operating device 50.

The body 200 has an X shape, and has four rotor arms at four ends of the X-shape, and each of which is equipped with a first horizontal rotor, a second horizontal rotor, a third horizontal rotor, and a third rotor that are rotatable around each of the rotating shafts. 4 horizontal rotor, the fuselage 200 includes a first wing drive mechanism, a second wing drive mechanism, a third wing drive mechanism, and a fourth wing drive mechanism that enable each horizontal rotor to rotate around the rotary shaft, and a first wing drive mechanism The built-in DC motor rotates the first wing drive mechanism or the like by the rotational force of the DC motor, and the body 200 includes control units that respectively control and monitor the operating states of the first to fourth wing drive mechanisms, and the control unit separately adjusts the respective wing drives. The rotational speed of the mechanism controls the direction and speed of movement of the unmanned aircraft. Four height measuring devices 290 are provided below the telecentric end of the four rotor arms (away from the end of the fuselage 200) for measuring the height of the unmanned aircraft from the water surface. When the unmanned aircraft hovering above the water surface, the X-shaped main axis of the fuselage 200 is parallel to the horizontal plane, and the four arms are the same height from the water surface; when the unmanned aircraft moves horizontally above the water surface, the X-shaped spindle of the fuselage 200 The roll, the lowest point is always at the telecentric end of the rotor arm, so the height measuring device 290 is disposed at the telecentric end of the rotor arm to ensure that the lowest point of the fuselage 200 is not submerged. When the drone is flying close to the surface of the water, the aforementioned height measuring device 290 is required to have a measurement accuracy of the millimeter level. In the field of unmanned aircraft, a barometric altitude sensor is typically used to detect the altitude of the flight. The error of the barometric height sensor is large, it is difficult to meet the requirements of accurate height measurement, and the accuracy of the measurement height is greatly affected by the influence of wind, temperature, humidity, dust particles on the near ground (water surface). Some of the unmanned aerial vehicles used for geographic mapping use a laser altimeter, but the laser has strong directivity. When the dip angle between the unmanned aircraft fuselage and the horizontal plane is large, it is difficult to accept the returning laser signal, and when measuring the fuselage When the water surface is away, it is necessary to pre-set the floating target on the water surface, and it is not suitable for use in the near ground (water surface) range. The pulsed ultrasonic measuring instrument has a low measurement accuracy and a large blind area (in meters), which is also incapable of the requirements of the present invention. Therefore, in the present invention, the height measuring device 290 selects a phase ultrasonic height measuring instrument with high measurement accuracy (error of about 2-6 mm) and small dead zone (2-40 mm). In addition, a temperature compensation device can be added to the above ultrasonic height measuring instrument to reduce the influence of large temperature changes near the ground. Each ultrasonic height gauge should use a different carrier frequency to prevent crosstalk. Preferably, in order to measure the accurate distance from the water surface when the body 200 is close to the water surface, the inclination of the body can also be detected by the body balance detecting device. When the inclination is greater than a predetermined threshold, The ultrasonic height measuring instrument is used to detect the distance from the rotor arm of the airframe 200 to the water surface, and according to the tilting angle and the distance, a trigonometric function transformation is performed by a control unit 250 or other module having a calculation function to obtain a close to the water surface. The exact height of the unmanned aircraft 200 from the water surface.

The body 200 is provided with a control unit 250 and a drive device 260. The control unit 250 controls the action of the unmanned aircraft, and the drive unit 260 can move and/or rotate the photographing device 300 in a specified direction with respect to the body 200. The control unit 250 is incorporated into a micro-multipurpose computer built into the body portion of the body 200 in the center of the X-shape. The driving device 260 is disposed on the front end of the support arm 270 to reduce the load when the photographing device 300 is rotated. The support arm 270 hangs from directly below the main body portion of the body 200 and is rotatable relative to the body 200. The support arm 270 hangs from directly below the main body portion of the body 200, and is rotatable in a plurality of directions with respect to the body 200 such that the body 200 is relatively stationary with respect to the photographing device 300, thereby preventing the unmanned aircraft from being Shake the body during work to avoid affecting the stability of the picture. Further, the driving device 260 may also be disposed inside the photographing device 300.

While the body 200 is kept in the air, the photographic device 300 provided with the lens module is immersed in water to capture images in the water. The photographing device 300 mounted on the body 200 is equipped with a fisheye lens module 320 having a viewing angle greater than or equal to 180 degrees. The bottom surface of the photographing device 300 is an inverted flat cone to prevent the viewing angle of the fisheye first lens module 320 from being blocked. The photographing device 300 further includes a photographing device balance detecting device. The photographing device balance detecting device may be an electronic level meter, an optical type gyroscope, a gyroscope or the like for detecting an angle between a posture of the photographing device 300 and a horizontal plane. The posture control device is provided on the body 200 or the photographing device 300, and is connected to the photographing device balance detecting device and the driving device 260, respectively. The posture control device can employ a microcontroller. The body 200 can use the posture control device to obtain an angle between the photographing device 300 and the horizontal plane by the photographing device balance detecting device, and control the driving device 260 according to the angle, and control the driving device 260 to tilt the photographing device 300 relative to the body 200 The direction is rotated to compensate the tilt angle of the body 200 such that the optical axis of the lens module 320 on the photographing device 300 is at right angles to the horizontal plane. The photographing device 300 captures an image from the fisheye lens module 320. The photographing apparatus 300 further includes a photographing unit that is disposed on the incident side and the opposite optical axis of the light incident on the lens module 320 to capture an image from the lens module 320. The photography department refers to an image sensor such as a CCD or a CMOS. In addition, the lens surface of the lens module 320 is also coated with a water-repellent or hydrophilic coating to improve the hydrophobicity of the lens surface to prevent moisture from eroding the lens and residual water droplets after the lens module leaves the water surface. Evaporation forms a large area of water stains, which in turn affects imaging. Illustratively, the material may be plated on the outermost lens surface of the lens module 320 by physical vapor deposition or sputter deposition, wherein the selection of the feed is a result of suitable selection by those skilled in the art.

The driving device 260 is used as a loading mechanism to mount the photographing device 300, and serves as a driving mechanism to change the angle of the body 200 with respect to the photographing device 300. The loading mechanism refers to a mechanism that can mount components and can rotate 360°, for example, a bearing that extends on a central surface of the photographing device 300 opposite to the driving device 260 and that extends in a direction orthogonal to the optical axis direction of the lens module 320, The drive unit 260 may include a rotating shaft that extends in the same direction as the bearing and is fitted to the bearing. In this case, the driving device 260 supports the imaging device 300 by fitting the rotating shaft to the bearing, and rotates the imaging device 300 by rotating the shaft and the bearing. On the other hand, as the drive mechanism, for example, a non-coaxial sector gear group having a rotation center as a rotation center and a plurality of teeth on the outer circumference is formed on the outer surface of the photographing device 300 opposite to the drive device 260, and the drive device 260 can be It has a motor and a circular gear that can control the number of rotations such as a stepping motor or a servo motor. The gear is supported by a rotating shaft of the motor, and has teeth on the outer circumference that are complementary to the teeth of the sector gear. In this case, the driving device 260 causes the teeth of the circular gear and the teeth of the sector gear to mesh with each other, and changes the rotational force of the motor to the rotational force of the sector gear, thereby changing the angle of the body 200 with respect to the imaging device 300. There are at least two sets of sector gears whose gear axes are orthogonal to each other to achieve a pair of rotations in an orthogonal direction.

The control unit 250 of the body 200 includes a control unit, a storage unit, a communication unit, and an image processing device. The storage stores the angle of deflection of the optical axis of the unmanned aircraft fuselage or lens module relative to the horizontal plane, and the correspondence between the height of the photographic device in which the unmanned aircraft body or the lens module is located with respect to the water surface. data. After detecting the angle of deflection of the optical axis of the unmanned aircraft body or the lens module relative to the horizontal plane, the corresponding relationship in the memory may be queried according to the value of the deflection angle to obtain the fuselage 200 or the lens module 320. The height of the water is estimated to quickly adjust the flying height of the unmanned aircraft. In addition, the storage device can also store the corresponding relationship between the flying speed of the unmanned aircraft and the optical axis compensation angle of the corresponding lens module 320. After the flying speed of the unmanned aircraft is obtained by using the sensor, the lens module 320 is obtained by looking up the table. The optical axis compensates for the estimated angle and performs angle compensation. The communication unit communicates with the outside through wireless communication. The body 200 is further provided with a body balance detecting device composed of an electronic level or a gyroscope for detecting a deflection angle between the body and the horizontal plane.

The control unit receives a command from the operation device via the communication unit, and transmits a video signal of the imaging unit that images the image from the lens module 320 to the operation device. The control unit controls the first horizontal rotor drive mechanism or the like according to an instruction of the operating device to control take-off, flight, and landing of the unmanned aircraft.

The control unit controls the lens driving unit in accordance with an instruction of the operating device. In addition to the instructions related to the optical axis variation operation of the lens module 320, the command may also include instructions related to the tilting operation of the lens module 320 to manually change the optical axis. Also, the optical axis of the lens module 320 can be automatically adjusted according to the geographic data of the object being photographed.

The control unit controls the driving device 260 to change the angle of the photographing device 300 with respect to the body 200 to compensate for variations in the moving direction or the geographical position of the photographing object. The control unit may control the driving device 260 according to a control program that is prepared in advance, or may control the driving device 260 according to a signal from the photographing device or the body balance detecting device, and may also control the driving device 260 with reference to the table data stored in the memory. Further, the control unit may control the drive unit 260 by the posture control device.

The unmanned aircraft landed from the air above the surface of the water according to preset procedures or manual remote control. During the landing process, the unmanned aircraft uses the four height measuring devices 290 provided on the rotor arms to detect the height from the water surface respectively, guiding the degree of the drone to descend, so that the fuselage 200 hovering over the water surface while photographing The device 300 is partially or fully submerged in water. In the current state, since the unmanned aircraft is relatively stationary in the horizontal direction, the angle between the fisheye lens module 320 of the photographing device 300 and the horizontal direction is 90 degrees, and the fisheye lens module 320 reaches the maximum viewing range. Therefore, no compensation is required.

The schematic diagram of the unmanned aircraft moving in the direction of the arrow in Fig. 2, the direction indicated by the arrow is the direction of travel. When the unmanned aircraft moves in the horizontal direction, the two horizontal rotors on one side of the moving direction lowers the rotational speed, the body 200 is tilted in the moving direction, and the photographing device 300 connected to the body 200 is also tilted. At this time, if the optical axis compensation is not performed on the photographing device 300, the image taken by the photographing device 300 is deflected, and the image on the side in the tilt direction of the body 200 is missing.

When the photographing device balance detecting device measures that the optical axis direction of the fisheye lens module 320 is not perpendicular to the horizontal direction, the posture control device adjusts the photographing device according to the change of the angle between the optical axis direction and the horizontal direction of the fisheye lens module 320. With respect to the angle of the body 200, the optical axis direction of the fisheye lens module 320 is perpendicular to the horizontal direction.

When the unmanned aircraft with rotors hover or move near the water surface, due to the effect of the ground effect (wing effect), the lift coefficient of the unmanned aircraft rises sharply, and residual power occurs, eventually causing the drone to drift. The ground effect is caused by the reaction of the ground or water to the rotor wake of the unmanned aircraft, and is affected by factors such as the radius of the rotor, the height of the unmanned aircraft from the ground or water surface, and the flatness of the ground or water surface. According to the test, when the rotor radius is constant, the lift coefficient and the distance between the unmanned aircraft and the water surface are nonlinear in a certain range (approximately from the surface of the water surface to the distance from the water surface within 3.5 times the radius of the rotor). In this range, it is difficult to achieve compensation by the algorithm of the rotor control, and the unmanned aircraft is not easy to achieve stable hovering. When the flying height is slightly higher than the range, the lift coefficient tends to be approximately constant, and the hovering control is easier to achieve. At this time, the lift coefficient is still greater than the lift coefficient when moving away from the water surface, and the flight at the height is beneficial to reduce the The energy consumption of the human aircraft improves the life time; when the flight altitude is 4.5 times the radius of the rotor, the unmanned aircraft basically gets rid of the ground effect. In addition, when the unmanned aircraft hovering near the water surface turns to the horizontal motion at the same height, the lift coefficient is also likely to change greatly. The lift coefficient at this time is in a nonlinear relationship with the distance between the unmanned aircraft and the water surface. Slightly smaller than the range of nonlinear relationships when hovering over the water. For this reason, the support arm 270 is equipped with a telescopic mechanism capable of being driven by the motor to be elongated or shortened. The telescopic mechanism can adopt a stepping motor to drive the combination of the gear and the rack to achieve elongation shortening, and can also be used in the outer telescopic cylinder. The inner side is engraved with a spiral track, and the motor is used to push the inner telescopic cylinder to advance spirally in the direction of the main axis. When the telescopic mechanism is extended to the maximum, the maximum length of the support arm is 3.5 times to 4.5 times the radius of the rotor, so that the stable region of the ground effect can be used to stably control the flight state and extend the life time of the unmanned aircraft. In addition, the memory may store a correspondence table between the angle of deflection of the optical axis of the unmanned aircraft body or the lens module relative to the horizontal plane, and the degree of elongation of the telescopic mechanism of the support arm. When the unmanned aircraft is hovering to the horizontal motion, the deflection clamp of the optical axis of the unmanned aircraft fuselage or the lens module relative to the horizontal plane is measured according to each balance detecting device, and the corresponding data table in the memory is queried to obtain the telescopic mechanism. The length of the telescopic length is such that the depth of the water entering the photographic module remains the same when the unmanned aircraft changes from hovering to horizontal motion. In addition to preventing the unmanned aircraft from being affected by the ground effect, the telescopic mechanism can prevent the unmanned aircraft from flying too low and enter the detection blind zone of the height measuring device 290 to crash.

The photographing device may further be equipped with a water level measuring instrument and/or a buoy (not shown), and the water level measuring instrument detects an actual measured value, and can provide the water detecting depth of the photographing device 300 more accurately than the height measuring device 290, thereby The photographing device 300 is always kept at the same depth when photographing in water, and the detection dead zone of the height measuring device 290 can be overcome by the water level measuring instrument. When the support arm with the telescopic mechanism is used, the height measuring device 290 can be used to obtain an accurate telescopic length, and the inside of the pontoon has a cavity filled with air, which can provide buoyancy and prevent the photographic device from entering the water too fast and too deep to improve safety. . Further, the photographing device is provided with a fill light for underwater illumination in the same direction as the optical axis of the lens module. Preferably, the fill light is four or more, and is disposed around the lens module at equal intervals to improve visibility in the water and reduce the loss of corners of the fisheye lens module which are prone to occur in a dark environment.

The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, and can be made without departing from the spirit of the invention within the scope of the knowledge of those skilled in the art. Various changes.

Claims

An unmanned aircraft for underwater shooting, comprising:

body;

a photographing device disposed under the fuselage, the photographing device comprising a lens module;

a height measuring device disposed at the bottom of the fuselage for measuring a distance between the body and the water surface below;

a driving device disposed on the body or the photographing device for changing an angle of the photographing device relative to the body;

a posture control device disposed on the body or the photographing device for controlling the driving device;

A photographing device balance detecting device is disposed on the photographing device for detecting a deflection angle between an optical axis direction of the lens module and a horizontal plane.
The unmanned aircraft for underwater shooting according to claim 1, further comprising:

a body balance detecting device disposed on the body for detecting a deflection angle between the body and the horizontal plane;

a memory for storing a correspondence relationship between a deflection angle of an optical axis of the body or the lens module with respect to a horizontal plane and a height of the camera device in which the body or the lens module is located with respect to the water surface;

A control unit for controlling and monitoring the operating state of the unmanned aircraft.
The unmanned aircraft for underwater photography according to claim 1, further comprising: said body including at least one rotor arm extending outward in a horizontal direction relative to the body, said height The measuring device is placed at the bottom of the end of the rotor arm.
The unmanned aerial vehicle for underwater shooting according to claim 1, wherein the photographic device balance detecting device is an electronic level or a gyroscope, and the lens surface of the lens module is coated with water repellency or hydrophilicity. Plating.
The unmanned aerial vehicle for underwater shooting according to claim 1, wherein the lens module of the photographing device is a fisheye lens module having a viewing angle greater than or equal to 180 degrees, and the photographing device is provided with a water level. A measuring instrument and/or a pontoon, the photographic apparatus is provided with a fill light having the same direction as the optical axis of the lens module for underwater illumination.
The unmanned aerial vehicle for underwater photography according to claim 1, wherein the height measuring device is a phase ultrasonic height measuring instrument.
The unmanned aerial vehicle for underwater shooting according to any one of claims 1 to 6, wherein the bottom of the fuselage is provided with a support arm for connecting the photographing device, and the driving device is disposed on the support arm. The support arm is provided with a telescopic mechanism that elongates or shortens its length.