JP2020147266A - Variable wing kite - Google Patents

Abstract

To provide a flight body for aerial wind power generation, which enables flight control even when a tensile force of a tether is lost, and which enables stable takeoff/landing from/on the ground to be performed by thrust of a propeller attached to an airframe.SOLUTION: A variable wing kite can control a flight attitude without dependence on a tensile force of a tether by having the function of self-changing aerodynamic characteristics, and can be lifted up in the windy sky by thrust of propellers 20a and 20b even when a sufficient wind does not blow on the ground.SELECTED DRAWING: Figure 1

Description

It relates to a kite that can change aerodynamic characteristics in airborne wind power generation, can control turning and angle of attack, and can take off and land by a rotor.

Various studies have been conducted on airborne wind power generation using a wind stronger and more stable than the surface of the sky (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). Although its recognition is low in Japan and there are few researchers, in recent years, research and development has been actively carried out in Europe and the United States, and demonstration experiments of airborne wind power generation are in progress.

Unlike the tower type, the power generation method that converts the tension of a mooring winch such as a kite glider into torque and rotates the generator can evacuate to the ground at the limit of strength and ensure safety, so it is a promising power generation method in Japan where a typhoon hits. It is thought that.

Airborne wind power generation requires a flight platform for power generation such as gliders and kites with controllable turning and angle of attack. The conventional kite for airborne wind power generation controls the flight attitude by controlling the tension of tethers attached to a plurality of places by a control unit (Kite control unit: KCU) on the ground or in the air. In the case of gliders, flight control is performed by adding ailerons to fixed wings as usual.

When a wind power generator is provided in a flight platform as disclosed in Patent Document 1, efficient power generation is performed by maintaining the flight in the sky or by making a figure eight turn or the like to increase the flight speed. ..

As disclosed in Patent Document 2, even when the generator on the ground is rotated by the tension generated in the mooring winch to generate electricity, an elliptical turn or a figure eight turn is performed to obtain a strong tension to increase the speed of the machine. increase. Power is generated while pulling the tether. After the tether is pulled out, the angle of attack of the flight platform is made shallow to reduce the tension of the tether, and the winch is wound linearly with low power. The energy difference between the time of repeated power generation and the time of winding is the net amount of power generation.

Japanese Unexamined Patent Publication No. 05-296137 Special Table 2011-522167 Japanese Unexamined Patent Publication No. 2003-120511 US2017 / 0138346 A1

Conventional kites for airborne wind power generation control the flight attitude by controlling the tension of tethers attached to multiple locations, but there is a problem that if the tether loses tension due to changes in wind speed etc., it becomes uncontrollable. is there. In the case of a glider, the lift changes greatly depending on the angle of attack, so fine control is required to maintain the flight attitude.

In addition, in order to utilize the strong and stable wind in the sky, it is necessary to levitate a controllable aircraft to the sky, and a safe takeoff and landing method is an issue for both kites and gliders.
In the case of the kite, for example, as in Patent Document 4, a method of guiding from the ground to the sky while receiving the wind by swinging while adjusting the flight attitude with a tether around the installation point has been devised, but a wide range of starting places is secured. There is a drawback that requires.

In the case of a glider, it takes off vertically using the attached motor propeller, and then the propeller rotates in response to the wind to generate electricity. In the case of a glider, the weight is heavier than that of a kite, so a large thrust is required for the motor propeller that supports the aircraft vertically, and it is difficult to increase the efficiency of both takeoff and power generation with the same system.

As in Patent Document 3, it is characterized by the ability to levitate by supplying power from the ground, and by levitating in the air with its own levitation force, it is moored at a high altitude with strong winds, and an air vehicle mainly composed of a propeller that generates wind power. Is also devised, but since it has a structure without wings, it can be operated only in strong winds.

The present invention has been made in view of the above problems, and the problem to be solved is that flight control is possible even if the tension of the tether is lost, and stable takeoff and landing from the ground is attached to the aircraft. The purpose is to provide an airborne wind turbine that can be driven by the thrust of a propeller.

The flying object of the present invention is a kite in which two leading rods on the left and right are connected to the apex of the center rod by a link mechanism and a flexible sail is stretched, and a spreader slidably and orthogonally connected to the center rod. The spreader is slidably connected to the left and right leading rods, and the intersection of the center rod and the spreader has a mechanism that can be changed by a servomotor provided between each rod and the intersection. The kite can be opened and closed by moving it up and down to change the area, and the area of the left and right parts can be changed from the center rod of the kite by moving the intersection to the left and right, so the relationship between the center of gravity and the aerodynamic center can be changed. It features a kite that can be wirelessly or automatically steered.

One of the other aspects of the invention is based on a kite based on a kite that can ascend in the wind while moored by a tether attached to an appropriate position on the rod of the flying object and can be steered in the air, a controller, GPS. It is equipped with various sensors and batteries such as, and is capable of autonomous navigation. It stays in the air for applications such as wireless communication base stations, fixed-point observation, and airborne wind power generation, or meets the necessary requirements such as elliptical turning and figure eight flight. It is an airborne body that performs autonomous flight in the flight path.

One of the other aspects of the present invention may be such that it can ascend itself by having two or more motors and propellers based on the flying object, for example, two motors provided on an extension of a spreader. And by changing the direction of the thrust of the propeller by the tilt mechanism, it is a flying object with levitation ability that can control the flight by itself as a so-called bicopter. When this aircraft is used as a flight platform for airborne wind power generation, for example, it can be operated by omitting the tilt mechanism because it is bound by a tether and receives a slight wind and receives a force on the leeward side.

One of the other aspects of the present invention is a variable kite or the variable kite that can change the position of the aerodynamic center of the kite and the left and right areas by moving the intersection of the center rod and the spreader with a servomotor or the like. This is a control method characterized in that flight control is performed autonomously in an air vehicle equipped with two or more propellers and having a function of ascending by itself.

One of the other aspects of the present invention is a variable kite capable of performing flight control by changing the position of the aerodynamic center of the kite and the left and right areas by moving the position of the intersection of the center rod and the spreader with a servomotor or the like. Alternatively, when an air vehicle equipped with two or more propellers on the variable kite and having a function of ascending by itself is used for aerial wind power generation, autonomous flight that stays in the air using various sensors and controllers such as GPS, 8 It is a control program characterized in that a turning flight such as a character or an angle of attack is controlled by changing the tension and the angle of attack of the tether by deforming the kite.

The conventional kite for airborne wind power generation controls the flight posture by controlling the tension of tethers attached to multiple places with a controller on the ground or in the air, and it cannot ascend unless there is a certain amount of wind on the ground. However, according to the present invention, since the kite has a function of changing the aerodynamic characteristics by itself, the flight posture can be controlled regardless of the tension of the tether. Furthermore, even if there is not enough wind on the ground, the thrust of the propeller can ascend to a windy airspace above.

It is a figure which shows the structure of the flying body which concerns on one Embodiment of this invention. It is a figure explaining opening and closing of the kite wing of the flying body which concerns on one Embodiment. It is a figure explaining the change of the left-right area of the kite wing of the flying body which concerns on one Embodiment. It is a block diagram explaining the outline of the function of the control unit. It is a figure explaining the flight control by the variable kite wing of the flying body which concerns on one Embodiment. It is a figure explaining an example of the flight path at the time of performing aerial wind power generation.

The present invention is a variable-sweep wing kite that is composed of rods and has a flexible sail on the airframe, and can be steered by changing the positional relationship of the intersections of the rods with a servomotor to change its own aerodynamic characteristics. In addition, by providing two or more motors and propellers, the function of ascending to the air by itself and the configuration of autonomous navigation are realized.

FIG. 1 is a diagram showing a configuration of an air vehicle according to an embodiment of the present invention. The flying object 100 has a kite structure in which two leading rods (11a to 11b) on the left and right are connected by a link mechanism with one of the center rods 10 as the apex, and a flexible sail 15 is stretched, and can slide with the center rod. It has a spreader 12 that is orthogonal to each other and is connected so that it can slide with the left and right leading rods (11a to 11b), and the intersection position between the center rod and the spreader is changed to the left and right by the spreader servo 13, and the center servo 14 It has a mechanism that can change the intersection position of the center rod 10 and the spreader 12 up and down, and the kite opens and closes by moving the intersection up and down to change the area and the positional relationship between the center of gravity GC and the aerodynamic center AC. The area (15a to 15b) of the left and right parts of the sail can be changed by moving the intersection position to the left and right. The variable wing kite can be wirelessly or automatically controlled.

For example, by providing a motor and propellers (20a to 20b) on the extension of the spreader 12 and a tilt mechanism (21a to 21b) at the connecting portion thereof, the flying object itself can have a function of ascending. Power supply and flight control for obtaining the thrust of the propeller are performed by the power supply and the control unit 16.

If the tether (mooring line) 30 is attached to an appropriate position of the rod constituting the flying object 100 of the present invention and the thread 31 is appropriately adjusted in consideration of the positional relationship between the center of gravity and the aerodynamic center, the flight receives wind. It is a variable-sweep kite that is maneuverable and can ascend to the windy sky even when the wind is not blowing sufficiently on the ground. The tilt mechanism (21a to 21b) can be omitted as long as the vehicle floats while being bound by the tether 30 and receiving a force on the leeward side.

FIG. 2 is a diagram illustrating opening and closing of the kite wing of the flying object 100. When the center servo 14 is operated with respect to the reference state shown by the broken line to move the center rod 10 upward with respect to the spreader 12, two rods are symmetrical with respect to the plane of symmetry M as shown by the solid line. The angle formed by the leading rods (11a to 11b) becomes smaller, and the kite wings are closed. The relative positional relationship between the thread 31 and the aerodynamic center AC also changes, and the thread 31 moves further upward than the aerodynamic center AC. In this case, the kite has a smaller angle of attack against the wind, the tension of the tether is reduced, and the accessibility to the wind is improved.

FIG. 3 is a diagram illustrating a change in the left-right area of the kite wing of the flying object 100. When the spreader servo 13 is operated to move the center rod to the left with respect to the reference state shown by the broken line, the area of the left sail 15b becomes larger than the area of the right sail 15a as shown by the solid line, and the aerodynamic center. And the center of gravity also moves to the left. As a result, the lift on the left side of the aircraft 100 increases, so that the aircraft 100 starts turning to the right.

FIG. 4 is a block diagram illustrating an outline of the function of the control unit 40 of the flying object 100 of the present invention. As shown in the figure, the control unit 40 includes a control computer 41, an R / C receiver 42, a 3-axis gyro sensor 43, a 3-axis acceleration sensor 44, a 3-axis geomagnetic sensor 45, and a pressure sensor 46.

The control computer 41 controls the rotation direction and rotation speed of the center servo 14 and the spreader servo 13 by a control program recorded in the built-in memory, and also controls the rotation speeds of the motor and the propellers (20a to 20b). The output circuits 41a to 41f of the control computer 41 include motor amplifiers Amp1 and Amp2 for motors and propellers 20a and 20b, servo outputs Sv1 and Sv2 for tilting, center servo outputs Sv3 for opening and closing wings, and variable wing areas. The spreader servo output Sv4 for this purpose is connected to each.

A commercially available multicopter (so-called drone) controller equipped with a 3-axis gyro sensor, a 3-axis acceleration sensor, a 3-axis geomagnetic sensor, and a pressure sensor may be used for the control unit 40.

The control unit 40 mainly detects the inclination of the flying object 100 by using the angle information obtained by integrating the angular velocities output by the 3-axis gyro sensor. Further, the controller 40 corrects the offset amount of the 3-axis gyro sensor 43 by using the static tilt information output by the 3-axis acceleration sensor 44. As a result, the controller 40 can make the flying object 100 take an arbitrary flight attitude.

In addition to the above-mentioned attitude control, the control unit 40 measures the altitude with the pressure sensor 46, detects the flight position with the GPS receiver 47, and stays in the air according to the program incorporated in the control computer 41. It is possible to perform autonomous flight, turning flight such as figure 8 or angle of attack by changing the tension and angle of attack of the tether by deforming the kite.

FIG. 5 is a diagram illustrating flight control by the variable kite wing of the flying object 100 of the present invention. FIG. 5A is a reference state. FIG. 5B schematically shows the state of FIG. 2 described above. When the center rod 10 moves upward, the angle of attack against the wind becomes smaller and the accessibility to the wind becomes better, so that the tension of the tether also decreases. Therefore, in the airborne wind power generation, it is in a state of being used for rewinding the tether 30.

FIG. 5C schematically shows the state of FIG. 3 described above, and when the center rod 10 is moved to the left, the flying object 100 can be turned to the right. On the contrary, when the center rod 10 is moved to the left as shown in FIG. 5D, the flying object 100 can be turned to the left.

FIG. 6 is a diagram illustrating an example of a flight path when performing airborne wind power generation. A generator 50 is installed on the ground, and by pulling the tether 30, the generator can be rotated to generate electricity, and conversely, a mechanism for winding the tether as a motor is provided.

Although the aircraft 100 is on the ground in the initial state, it must take off to a strong and stable wind-blown sky in order to generate wind power. The aircraft 100 can take off by obtaining lift from the wind when a wind with a sufficient wind speed is blowing, but it is possible to take off by using the thrust of the propeller even if the wind speed is insufficient (51).

After reaching the sky, power is generated while rotating the generator with the tension of the tether (52). At that time, the greater the tension, the better the power generation efficiency. Therefore, it is effective to increase the flight speed by making a figure eight turn as shown in the figure while changing the kite wing.

There is a limit to the length of the tether 30, and the kite must support the weight of the tether itself as the tether 30 is pulled out. Therefore, when the tether 100 rises to an appropriate altitude (53 in the figure), the tether 100 Is in the state of rewinding in FIG. 5B described above, the tension of the tether 30 is lowered, and the tether 30 is rewound with as low power as possible. When the vehicle body 100 descends to the lower limit of the airspace where a stable and strong wind blows (54 in the figure), the vehicle body 100 is returned to the reference state of FIG. 5 (a) and power generation is restarted. Power generation and rewinding are repeated, and the energy difference between the two becomes the net amount of power generation.

10 ... Center rod, 11a to 11b ... Leading rod, 12 ... Spreader, 13 ... Spreader servo, 14 ... Center servo, 15 ... Sail, 15a ... Right side sail, 15b ... Left side sail, 16 ... Power supply and control unit, 20a to 20b ... Motors and propellers, 21a to 21b ... Tilt mechanism, 30 ... Tether (mooring line), 31 ... Thread, 40 ... Control unit, 41 ... Control computer, 41a to 51f ... Output circuit, 42 ... R / C receiver, 43 ... 3-axis gyro sensor, 44 ... 3-axis acceleration sensor, 45 ... 3-axis geomagnetic sensor, 46 ... pressure sensor, 47 ... GPS receiver, 50 ... generator, 51 ... air vehicle at takeoff, 52 ... at power generation Air vehicle, 53 ... Air vehicle with upper limit of tether, 54 ... Air vehicle with lower limit of boundary layer, 100 ... Air vehicle, AC ... Aerodynamic center, Amp1 to Amp2: Motor amplifier output, GC ... Center of gravity, M ... Symmetric plane, Sv1 to Sv4 : Servo output

Claims (7)

Two leading rods on the left and right are connected to the apex of the center rod by a link mechanism, and a flexible sail is stretched, and it has a spreader connected orthogonally to the center rod so that it can slide, and the center rod and the spreader A kite-shaped flying object that has a mechanism that allows the position of the intersection to be changed by a servomotor, and that can change the aerodynamic characteristics by moving the intersection up, down, left, and right. A kite that can be maneuvered in the air while being moored by a tether attached to the appropriate position of the rod of the flying object. An air vehicle that can ascend by itself by having two or more motors, a propeller, and a tilt mechanism of the motors based on the air vehicle. It has a function of being able to levitate by adding two or more motors and a tilt mechanism of a propeller and a motor to a kite that can be operated in the air by receiving wind while being moored by a tether attached to the rod of the flying object at an appropriate position. Air vehicle. An air vehicle that omits the tilt mechanism of the air vehicle according to claim 4. The control method and control program according to any one of claims 1 to 5, wherein the flight control is performed autonomously. The flying object according to any one of claims 2, 4, and 5, which may be an autonomous flight that stays in the air using various sensors and controllers such as GPS, or a turning flight such as a figure eight. A control program that controls flight by changing the tension and angle of attack of the tether by deforming the kite.