JP2021021663A - Method for measuring wind direction and wind velocity and unmanned aircraft used in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method capable of obtaining wind direction and wind speed information and an unmanned aerial vehicle used therefor, and to provide a measuring method capable of obtaining more detailed wind direction and wind speed information and an unmanned aerial vehicle used therefor. The purpose is to do. PROBLEM TO BE SOLVED: To provide a measuring method capable of obtaining wind direction and wind speed information and an unmanned aircraft used for the measurement method, and observation by a Doppler lidar or the like is performed at an airport or the like to obtain turbulence (wind speed in a three-dimensional direction). Although the wind direction and speed have been measured, there are problems such as the cost of the measuring device and the altitude resolution of about 10 m, but this method can obtain the wind direction and speed information more accurately. .. [Selection diagram] Fig. 2

Description

The present invention relates to a method for measuring wind direction and speed and an unmanned aerial vehicle used therein.

In recent years, unmanned aerial vehicles that can fly without a person on board and can acquire information near the surface of the earth have been widely developed and marketed.

Even among unmanned aerial vehicles, so-called drones that can autonomously stay at a specific position in the air (hovering) can be hovered by multiple rotors and rotor blades, and can be realized with a lightweight and inexpensive configuration. For this reason, it has become widespread in recent years.

On the other hand, meteorological observations are very important information in human economic activities near the surface of the earth and above it, and acquisition by various methods is being attempted.

As a technique related to the above, for example, Patent Document 1 below discloses an information collecting robot provided with sensor means for measuring ambient environment information.

Japanese Unexamined Patent Publication No. 2005-271781

However, although the information collecting robot described in the above document can measure the surrounding environment information, the measurement is only information on points such as the direction and the wind speed at the position, and more detailed wind direction and wind speed information. There is a problem that the amount of information is insufficient in order to obtain the information.

Therefore, in view of the above problems, an object of the present invention is to provide a measuring method capable of obtaining more detailed wind direction and wind speed information and an unmanned aerial vehicle used for the measurement method.

The method of measuring the wind direction and the wind speed using an unmanned aerial vehicle according to one aspect of solving the above problems includes a step of acquiring position information at a first position in the air, a step of hovering at the first position, and a gravity parameter. Except for, the step of turning off the feedback control and naturally moving to the second position, and the step of obtaining the wind direction and the wind speed based on the trajectory during the movement from the first position to the second position are provided.

Further, the unmanned aerial vehicle according to another aspect includes a spherical housing and a plurality of arms having a rotary blade extending radially from the housing and rotating by a rotary machine and a rotary machine in the vicinity of the tip. It is a thing.

As described above, according to the present invention, it is possible to provide a measuring method capable of obtaining more detailed wind direction and wind speed information and an unmanned aerial vehicle used therefor.

It is a figure which shows the flow of the wind direction and the wind speed measurement method which concerns on embodiment. It is the schematic about the position measurement of the unmanned aerial vehicle in the method of measuring the wind direction and the wind speed which concerns on embodiment. It is an image figure when the wind direction and the wind speed are obtained based on the locus in the wind direction and the wind speed measurement method which concerns on embodiment. It is a figure which shows the schematic appearance (squint) of the unmanned aerial vehicle which concerns on embodiment. It is a figure which shows the schematic appearance (top surface) of the unmanned aerial vehicle which concerns on embodiment. It is a figure which shows the functional block of the unmanned aerial vehicle which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be implemented in many different embodiments and is not limited to the specific examples described in the embodiments shown below.

(Measurement method of wind direction and speed)
FIG. 1 is a diagram showing an outline of a flow of a wind direction and wind speed measuring method (hereinafter referred to as “the present method”) according to the present embodiment. As shown in this figure, in this method, (1) a step of acquiring position information at the first position in the air, (2) a step of hovering at the first position, and (3) feedback control excluding gravity parameters are performed. It includes a step of turning it off and naturally moving it to a second position, and (4) a step of obtaining a wind direction and a wind speed based on a trajectory during the movement from the first position to the second position.

The unmanned aerial vehicle (hereinafter referred to as "the aircraft") used in the present method is not limited as long as the above steps can be performed and the effect of the present invention can be achieved, but a plurality of rotors A so-called drone including a plurality of arms including rotary blades connected to the rotary machine and rotating, and a housing portion to which the plurality of arms are connected is preferable. The rotary machine is not limited as long as it has a shaft and can rotate the shaft. For example, a motor driven by electricity or an engine rotor driven by liquid fuel may be used.

First, this method includes (1) a step of acquiring position information at the first position. Here, the "first position" means the information of two positions in the air in order to measure the wind direction and the wind speed obtained in this method, and the position where the measurement is started and the position where the measurement is finished. The term "first" itself has no meaning other than the above, as it is merely a term used to distinguish the two in the explanation of this method.

Here, the method of moving the aircraft to the first position is that the operator manually operates the aircraft using an operating machine (so-called remote controller or radio) and moves the aircraft to a desired position to start measurement. Well, you may set your favorite position as the first position while visually checking the coordinates, or you may autopilot to move to the preset aerial coordinates, and it is not particularly limited. Absent.

Further, the method of obtaining the position information in this "first position" is not limited, but GPS (Global Positioning System) for obtaining the position information by receiving radio waves from artificial satellites orbiting the earth is used. It is preferable to use it. In addition, since GPS can obtain three-dimensional information including altitude, it is possible to obtain an accurate wind direction and speed.

Further, among GPS, it is also preferable to use RTK-GPS (Real Time Kinetic GPS) that performs higher position measurement using position information data from a reference station installed on the ground. RTK-GPS is configured to receive radio waves from reference stations in addition to radio waves from artificial satellites used in GPS, and by taking into account the position information of the reference stations, the accuracy of measurement position by GPS is further improved. It is possible, and in the optimum case, the measurement accuracy can be within a few centimeters. The image in this case is shown in FIG. As will be described again in the configuration of the aircraft described later, the aircraft is equipped with a GPS receiver, and after acquiring the position information by the GPS receiver, it is recorded on the recording medium in the control device in the aircraft. Or, it is possible to output position information to a processing device on the ground by a wireless communication device.

Here, as is clear from the above description, the position information preferably includes latitude and longitude information, and further includes altitude information. In order to process this method more concretely, it is preferable to acquire the position information as data so that it can be processed as data by an information processing device, so-called computer, and more specifically, latitude data, longitude data, and so on. It is preferable to include altitude data. Further, in this case, it is preferable to include the time data in addition to the position information. By doing so, it is possible to obtain the wind direction and the wind speed based on the relationship with the second position information.

Further, this method includes (2) a step of hovering at the first position. Here, "hovering" refers to a flight state in which the aircraft stays near a point in the air. The term "neighborhood" here means that there is a range of error, etc., because it is practically impossible to completely keep the aircraft at one point in the air without error or fluctuation.

In this step, feedback control is performed so as to stay at that position, although not limited to the extent that hovering can be performed. More specifically, the aircraft is equipped with an acceleration sensor and a gyro sensor, and when changes occur, the number of rotations of the rotor blades is controlled so that the aircraft returns to its original position, and the aircraft stays in the same position. Control.

In addition, this method includes (3) a step of turning off the feedback control and naturally moving to the second position except for the gravity parameter. It is preferable that this step is started after the aircraft is sufficiently stabilized in the first position in the hovering.

In this step, turning off the feedback control means not performing the control to return to the original position in the feedback control for hovering described in (2) above, and "feedback excluding the gravity parameter". "Turning off control" means not considering at least one of a plurality of parameters used in feedback control, specifically, setting a parameter other than the gravity parameter to zero or an initial value. In addition, the gravity parameter is excluded here because it is the minimum necessary to prevent the aircraft from falling.

Here, the parameters in the feedback control will be described more specifically. Although various control parameters can be used, it is preferable to provide gravity parameters and thrust parameters.

The gravity parameter is a parameter that means the upward force (force in the opposite direction of gravity) required to enable the aircraft to float in the air against gravity, and by setting this parameter to an appropriate value, The aircraft will be able to stay in the same position. Gravity parameters are determined by the weight of the aircraft and may be set and fixed at the time of manufacture, and in an environment where factors other than own weight such as wind can be ignored when used by the user (for example). Actually start floating (indoors or in the air near the ground) (gradually increase the value of the thrust parameter), control while adjusting so that it stays at the same position, and the parameters obtained by that control (specifically, The thrust parameter's upward component in the direction of gravity) may be determined to be in balance with gravity and used as the gravity parameter. This gravity parameter is necessary to eliminate the influence of this wind when a wind blowing from above or a wind blowing from below is generated on the aircraft in the sky.

In addition, the thrust parameter is a parameter necessary for the aircraft to move freely in the sky and also for the aircraft to stay in the same position, and it rotates based on the thrust parameter and the gravity parameter. The aircraft can be rotated to fly the aircraft to the desired position or hover at the desired position. By using this thrust parameter, it is possible to move the aircraft so that it stays in the same position even if a force other than gravity is applied in the vertical direction or in the horizontal direction. it can. In addition, when hovering, a typical example of the force along the direction of gravity is based on the wind from top to bottom or from bottom to top (the force of the vertical component of the wind including these components). Yes, a typical example of a force along the horizontal direction is based on the wind along the horizontal direction (the force of the horizontal component of the wind containing these components). Thrust parameters have three-dimensional components in the horizontal and gravitational directions (vertical direction). Of course, by controlling the magnitude of this thrust parameter, the aircraft can ascend to a desired position at a desired speed.

As is clear from the above description, the feedback control for hovering means adjusting the thrust parameters other than the gravity parameter so that the aircraft stays in the same position. That is, it can be considered that this thrust parameter generated during hovering is a parameter generated by the influence of the wind in the air. The thrust parameter is three-dimensional and includes components in the gravitational direction (vertical direction) as well as in the horizontal direction. As described above, the gravitational direction (vertical direction) is derived from the vertical component of the wind in the place, and the horizontal direction is derived from the horizontal component of the wind in the place. Then, from this state, if the thrust parameter is set to zero, only the gravity parameter due to its own weight remains, and it is possible to be affected only by the wind.

According to this step, the aircraft will be affected only by the wind, and the movement of the aircraft can be considered to be purely affected by the wind (wind direction / speed). The period for which this step is performed may be a predetermined period set in advance, a period until the aircraft moves by a predetermined distance, or a period until the operator of the aircraft stops the aircraft arbitrarily. An obstacle sensor for detecting an obstacle may be provided in the aircraft, and the period may be set until the sensor detects an obstacle and the aircraft stops when it is about to collide with an obstacle or the like.

Further, this method includes (4) a step of obtaining the wind direction and the wind speed based on the trajectory during the movement from the first position to the second position. FIG. 3 shows an image in the description of this step. As shown in this figure, the aircraft first ascends, hoveres, and then turns off feedback control to move naturally.

Here, the "second position" refers to the position of the aircraft at the time when the step (3) is completed, and the "second" is used to distinguish it from the "first position". It is just a term used for, and has no other technical meaning.

In this step, the locus during the movement from the first position to the second position is obtained. Here, the "trajectory" refers to a time change of position information, and specifically means that a plurality of data composed of a combination of position information data and the time data are provided.

Here, the wind speed and the wind direction (specifically, the wind speed data and the wind direction data) can be obtained by various methods, but can be obtained by the following formula.

In the above equation, the dynamic pressure P can be obtained as a value obtained by dividing the distance flowed in the sky by the time. This can be easily calculated by using at least two combinations of position information and its time.

Further, in the above equation, the air density ρ can be obtained from the temperature and atmospheric pressure of air by using the gas state equation. That is, by equipping the aircraft with a thermometer and a barometer, it is possible to obtain the temperature and atmospheric pressure at the position and time, and it is possible to obtain the air density on the spot.

In the above formula, the drag coefficient C _D is a value which may occur by the shape possessed by the present aircraft, a constant determined at time of manufacture of the aircraft.

In the above formula, also the surface area S, as with the drag coefficient C _D, be one that depends on the shape of the aircraft, a constant determined at time of manufacture of the aircraft. That is, in this method, it is possible to determine the velocity V by appropriately obtaining the dynamic pressure P and the air density ρ, and more specifically, by obtaining the change in the position information and the air density at the position. In particular, in this method, since the position information includes a three-dimensional element, the velocity V can also be obtained three-dimensionally.

As described above, this method makes it possible to provide a measuring method capable of obtaining more detailed wind direction and wind speed information and an unmanned aerial vehicle used for the measuring method. Recently, at airports, etc., observations by Doppler lidar etc. have been carried out to measure the wind direction and speed of eddy (wind speed in the three-dimensional direction), but the measuring device is expensive and the altitude resolution is about 10 m. Although there are some problems, this method can obtain wind direction and wind speed information more accurately.

(Unmanned aerial vehicle)
The structure of this method is not limited as long as the above steps can be realized and the wind direction and speed can be measured, but it can be more easily achieved by using an unmanned aerial vehicle having the following structure, for example. it can. This will be described in detail below.

FIG. 4 is a schematic perspective view of the appearance of the unmanned aerial vehicle (hereinafter referred to as “the aircraft”) 1 according to the present embodiment, and FIG. 5 is a top view thereof. Further, FIG. 6 is a diagram showing a functional block of the aircraft. As shown in this figure, the aircraft is provided with a spherical housing 2 and a plurality of arms 3 extending radially from the housing 2 and having a rotor 31 and a rotor 32 in the vicinity of the tip. The control device 4 for controlling the rotor 31 and the rotor 32 is housed in the housing 2. In FIG. 6, for the sake of brevity, only two rotating machines are shown, but in reality, as described above, a plurality of rotating machines are independently connected to the control device and are controlled independently.

The housing 2 in the aircraft 1 houses the control device 4 necessary for controlling the aircraft 1. The shape of the housing 2 is not limited, but is preferably a spherical shape as shown in the above figure. The spherical shape makes it possible to receive wind evenly from any direction, up, down, left, or right, so that a more accurate wind direction and speed can be obtained. In particular, since the aircraft 1 can move independently, there is an advantage that it is possible to follow a complicated wind flow such as a winding wind.

Further, as described above, the arm 3 in the aircraft 1 is a member for supporting the rotor 31 and the rotor 32 at a desired distance from the housing, and also arranges and controls a lead wire inside the arm 3. It is a member for being able to be connected to the device 4.

Further, in the aircraft 1, a plurality of arms 3 are provided as described above, and it is preferable that these are arranged so as to be point-symmetrical from the center of the spherical housing. By arranging them so as to be point-symmetrical, it is possible to obtain buoyancy evenly and to receive the direction and strength of the wind evenly from any direction. In particular, it is preferable that the spheres are evenly arranged in the front-back, left-right, and up-down directions from the center of the sphere. In this case, the number of arms 3 is not limited, but is preferably 4 or more, more preferably 6 (3 each vertically symmetrically), and further preferably 8 as shown in the above figure. (4 each vertically symmetrically). By arranging a large number of them evenly, it is possible to receive the wind evenly from any direction.

The rotary machine 31 in the aircraft 1 is used to rotate the rotary blade 32, and the lift can be adjusted by controlling the rotation speed. Further, the rotary blade 32 in the aircraft 1 is used to generate lift, and is connected to the rotary machine to rotate.

Further, the aircraft 1 may be provided with an imaging device for acquiring image information on the ground surface and the surrounding environment, and as described above, a thermometer, a barometer, a gyro sensor, and an acceleration sensor.

In addition, in this aircraft 1, parameter control other than gravity parameters is turned off from hovering, and it is left to the pressure of the wind to float freely. Therefore, in order to avoid contact when an obstacle or the like exists nearby. It is preferable to provide an obstacle sensor. As the obstacle sensor, a distance sensor for measuring a distance, more specifically, an optical sensor such as an infrared sensor is a preferable example.

Further, as is clear from the above description, the aircraft 1 is provided with a position information acquisition device for acquiring position information. The position information acquisition device is not particularly limited, but a receiver for receiving radio waves when using GPS (including RTK-GPS) is more preferable.

It is preferable that the aircraft is provided with a transmitter for transmitting information acquired by the aircraft by the various sensors described above. By doing so, the information acquired by the aircraft can be processed by a processing device separately provided on the ground or the like, and the weight burden, processing burden, etc. of the aircraft can be reduced.

Further, in the housing 2 of the aircraft 1, the rotary machine 31, the rotary blade 32, the image pickup device, the position information acquisition device, the transmitter, and the control device 4 capable of controlling various sensors are provided. The control device 4 receives an instruction signal from the operation device operated by the operator on the ground, and performs a predetermined process (rotational speed control of the rotating machine, etc.).

The aircraft 1 is provided with an operating device (remote controller, radio) for operating from the ground, and the operator performs processing necessary for controlling the aircraft.

Further, a processing device is provided on the ground and is connected to the operating device or the aircraft to process the above-mentioned wind direction and speed processing. A so-called computer can be used as this processing device.

The present invention has industrial applicability as a method for measuring wind direction and speed and an unmanned aerial vehicle used therein.

Claims (3)

Steps to get location information at the first position in the air,
The step of hovering in the first position,
Steps to turn off feedback control and move naturally to a second position in the air, except for gravity parameters,
A method of measuring a wind direction and a wind speed using an unmanned aerial vehicle including a step of obtaining a wind direction and a wind speed based on a trajectory while moving from the first position to the second position. With a spherical housing,
An unmanned aerial vehicle including a rotating machine and a plurality of arms having rotary wings rotated by the rotating machine in the vicinity of the tip, which are radially extended from the housing. The unmanned aerial vehicle according to claim 2, wherein the plurality of arms are arranged so as to be point-finished from the center of the spherical housing.