JP2021112961A - Morphological transition control device, vertical takeoff and landing aircraft, morphological transition control method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air vehicle control device for transitioning the form of an air vehicle having a portion whose form is gradually changed without deviating from a safe flight range.
An automatic transition control rule 35 is applied to an air vehicle, such as a four-engine tilt airfoil VTOL aircraft having wings that are parts for stepwise transitions. For the target flight speed of the 4-engine tilt wing type VTOL aircraft, the speed target command limit value generator 351 that limits the flight speed target command to the range based on the current form, and the current wing based on the limited flight speed target command. A tilt angle scheduler 353 for determining whether to transition from the tilt angle to the next stage tilt angle is provided.
[Selection diagram] Fig. 6

Description

The present invention relates to a morphological transition control device, a morphological transition control method, and a program used for controlling the tilt angle of a vertical takeoff and landing aircraft represented by a 4-engine tilt airfoil VTOL (Vertical Takeoff Landing) aircraft. The present invention also relates to a vertical take-off and landing aircraft having such a morphological transition control device.

The 4-engine tilt-wing VTOL aircraft is a new type of aircraft that achieves both vertical take-off and landing capabilities such as helicopters and high-speed long-distance flight performance comparable to that of fixed-wing aircraft. It has tandem wings and propellers arranged in the front and rear, and by rotating these with a tilt mechanism, it transitions from helicopter mode to airplane mode. The ability to take off and land from a narrow area without a runway and to advance far away shortens the travel time of Door-To-Door and streamlines observation of the area, so not only passenger aircraft but also unmanned aerial vehicles It is expected to be a promising technology in the field.

The research and technological development so far are as follows.
-Flight from vertical takeoff and landing (helicopter mode) with the main wing tilt angle vertical (Tilt = 90 degrees) to cruising (airplane mode) with the tilt angle horizontal (Tilt = 0 degrees) (hereinafter referred to as "complete" A tandem main wing design method (shape design) for realizing (referred to as "transition") (see Non-Patent Documents 1 and 2).
-Understanding the basic aerodynamic characteristics covering the flight area for complete transition (see Non-Patent Documents 1 and 2).
-A maneuvering system configuration method for enabling complete transition flight by manual maneuvering (see Patent Document 1).
-A technology related to the attitude control rule design method (see Patent Document 1) for enabling complete transition flight by manual attitude angle command has been developed, and its effectiveness has been confirmed by flight demonstration using a small unmanned experimental aircraft.
-A guidance rule for realizing automatic program flight (navigation) has been developed, and its effectiveness has been confirmed by flight demonstration using a small unmanned experimental aircraft (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2014-231263 Japanese Unexamined Patent Publication No. 2019-073179

K. Muraoka, N.M. Okada AND D. Kubo: Quad tiltwing VTOL UAV: aerodynamic charactics AND prototype flight test, AIM 2009-1834, 2009. K. Muraoka, N.M. Okada, D.M. Kubo AND M. Sato "Transition Flight of Quad Tiltwing VTOL UAV" Proceedings of the 28th International Congress of the Aeronautical Sciences, 2012.

In the technology developed so far, it is necessary to build an automatic transition control rule for the tilt angle when automatically making a transition flight of a 4-engine tilt wing type VTOL aircraft, but while preventing deviation from the safe flight range (transition corridor). There is no control law design method for acceleration transitions and deceleration transitions.

In view of the above circumstances, an object of the present invention is a morphological transition control device, vertical To provide takeoff and landing aircraft, morphological transition control methods and programs.

In order to achieve the above object, the morphological transition control device according to the present invention is a morphological transition control device of an air vehicle having a portion for stepwise transition of the morphology, and is currently relative to the target flight speed of the air vehicle. A speed target command range limiting unit that limits the flight speed target command to a range based on the form, and a form transition determination unit that determines whether to transition the form from the current form to the next stage form based on the restricted flight speed target command. And.

The mode transition control device according to one embodiment of the present invention further includes a first limit value table in which a range of the flight speed target command is set for each of the modes of each stage, and the speed target command range limiting unit is provided. , The range of the flight speed target command is limited based on the range of the set flight speed target command.

The form transition control device according to one aspect of the present invention further includes a second limit value table in which a threshold value for whether or not to transition the current form to the next stage form is set for each of the above forms in each stage. The morphological transition determination unit determines whether to transition the morphology from the current morphology to the next stage morphology based on the threshold value.

In the mode transition control device according to one embodiment of the present invention, the threshold value is set within the range of the flight speed target command of the embodiment.

The form transition control device according to one embodiment of the present invention further includes a speed target command change limiting unit that limits changes in the flight speed target command limited to a range based on the current form based on the current flight speed of the flying object. Equipped.

The mode transition control device according to one embodiment of the present invention further includes a third limit value table in which a limit value for limiting the change of the flight speed target command is set for each of the modes of each stage, and the mode transition The determination unit limits the change of the flight speed target command based on the limit value.

In the morphological transition control device according to one embodiment of the present invention, the flying object has an airspeed sensor, and the morphological transition determining unit has the current flight speed based on a detection value detected by the airspeed sensor. To judge.

In the form transition control device according to one embodiment of the present invention, the flying object has a servo mechanism for stepwise transitioning the form in response to a transition command, and the form transition determination unit uses the transition command. Based on this, the current form is determined.

The vertical take-off and landing aircraft according to one embodiment of the present invention has a morphological transition control device having the above configuration, and a wing that changes the tilt angle of the vertical take-off and landing aircraft is a portion where the morphological transition is performed stepwise.

The morphological transition control method according to the present invention is a method for controlling the morphological transition of an air vehicle having a portion for stepwise morphological transition, and is a range based on the current morphology with respect to the target flight speed of the air vehicle. The flight speed target command is limited to, and it is determined whether to transition the form from the current form to the next stage form based on the restricted flight speed target command.

The program according to the present invention is a program for controlling the morphological transition of an air vehicle having a portion for stepwise morphological transition, and is within a range based on the current morphology with respect to the target flight speed of the air vehicle. The computer is made to execute a step of limiting the flight speed target command and a step of determining whether to transition the form from the current form to the next stage form based on the limited flight speed target command.

According to the present invention, the form of an air vehicle having a portion for which the form is changed stepwise can be changed without departing from the safe flight range.

It is a figure which shows the outline of the 4-engine tilt airfoil type VTOL machine which concerns on one Embodiment of this invention. It is a figure which shows the system structure of the 4-engine tilt wing type VTOL machine which concerns on one Embodiment of this invention. It is a block diagram which shows the schematic structure of the control computer shown in FIG. It is a table which shows an example of the tilt angle change schedule from vertical takeoff to cruising flight of a 4-engine tilt wing type VTOL aircraft. It is a graph which shows the safe flight range (transition corridor) in relation to FIG. It is a block diagram which shows the structure of the automatic transition control rule shown in FIG. It is a table which shows an example of the limit value table used by the automatic transition control rule shown in FIG. It is a graph which shows the safe flight range (transition corridor) in relation to the limit value of the limit value table shown in FIG. 7. It is a flowchart which shows the operation of the automatic transition control rule shown in FIG. It is explanatory drawing of the problem to be solved by this invention. It is a top view which shows the flight plan used for the flight simulation of the 4-engine tilt wing type VTOL machine which concerns on this invention. It is a top view which shows the flight locus in a horizontal plane among the flight simulation results of the 4-engine tilt airfoil VTOL machine which concerns on this invention. It is a graph which shows the time history (parameter in a vertical plane) in the flight simulation result of the 4-engine tilt airfoil VTOL machine which concerns on this invention. It is a graph which shows the time history (horizontal parameter) in the flight simulation result of the 4-engine tilt airfoil type VTOL machine which concerns on this invention. It is a graph which shows the transition speed (relationship between a tilt angle and a speed) in the flight simulation result of the 4-engine tilt wing type VTOL machine which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Outline of 4-engine tilt-wing VTOL aircraft]
FIG. 1 is a diagram showing an outline of a four-engine tilt-blade VTOL aircraft according to an embodiment of the present invention.
The 4-engine tilt wing type VTOL aircraft 1 has four wings 11 on the left, right, front and rear that can be tilted. A propeller 12 is attached to the front of each of the wings 11, and a flaperon (used as a flap, an elevator, and an aileron) 13 is provided behind each of the wings 11. Further, the 4-engine tilt wing type VTOL aircraft 1 has a tail wing 14, and the tail wing 14 is provided with a ladder 15.

The four-engine tilt-wing VTOL aircraft 1 has three modes: vertical takeoff and landing mode, transition mode, and airplane mode. In the vertical takeoff and landing mode, the 4-engine tilt wing type VTOL aircraft 1 tilts the wing 11 so that each propeller 12 faces upward. In this case, the wings 11 are vertical. In airplane mode, the 4-engine tilt-wing VTOL aircraft 1 tilts the wings 11 so that each propeller 12 faces forward. In this case, the wing 11 is horizontal. In the transition mode, the 4-engine tilt wing type VTOL aircraft 1 tilts the wing 11 so that the propeller 12 faces diagonally upward at a predetermined angle.

At takeoff, the 4-engine tilt-wing VTOL aircraft 1 typically takes off in the same manner as a normal helicopter by switching modes in the order of vertical takeoff and landing mode, then transition mode, and airplane mode to achieve the desired altitude. When it reaches it, it will fly in the same form as a normal airplane. At the time of landing, the 4-engine tilt-wing VTOL aircraft 1 typically switches modes in the order of flight mode, transition mode, and vertical takeoff and landing mode, and immediately before landing, it lands in the same form as a normal helicopter.

[System configuration of 4-engine tilt-wing VTOL aircraft]
FIG. 2 is a diagram showing a system configuration of a 4-engine tilt airfoil VTOL aircraft 1.
The four-engine tilt wing type VTOL machine 1 includes four motors 16 for driving each propeller 12 and four flaperon driving units 17 for driving four flaperons 13 provided on each wing 11 (# 1 to 4). It has two tilt drive units 18 for tilt-driving a pair of front blades 11 and a pair of rear blades 11, and one ladder drive unit 19 for driving a rudder 15 provided on the tail blade 14.

The four-engine tilt wing type VTOL machine 1 controls four motor speed controllers 20 that control the speed of each motor 16, a flaperon angle servo 21a that controls each flaperon drive unit 17, and each tilt drive unit 18. It has two tilt angle servos 21b and a rudder servo 22 that controls the rudder drive unit 19.

The 4-engine tilt-wing VTOL machine 1 further includes a GPS / INS sensor 23, an air data sensor 24, a system status sensor 25, a power power supply 26, a system power supply 27, an RC receiver 28, and an extra small size. It has a modem 29 and a control computer 30.

The GPS / INS sensor 23 detects latitude / longitude, GPS altitude, ground speed, elevating rate, attitude, acceleration, and the like. The air data sensor 24 detects airspeed, barometric altitude, and the like. The system status sensor 25 detects the rotation speed, current, voltage, temperature, and the like of the motor 16. The detection results of the GPS / INS sensor 23, the air data sensor 24, and the system status sensor 25 are typically the attitude angle (pitch, roll, yaw) and speed (X direction, Y direction, Z direction) of the aircraft. ), Position (X, Y, Z), acceleration, angular acceleration, etc., which are input to the control computer 30.

The power power source 26 supplies electric power to the motor 16 via the motor speed controller 20. The system power supply 27 includes a flaperon servo 21a, a tilt servo 21b, a ladder servo 22, a GPS / INS sensor 23, an air data sensor 24, a system status sensor 25, an RC receiver 28, an extra small modem 29, and a control computer 30. Power to.

The RC receiver 28 receives a manual control command from the remote control device (propo) 131. The extra small modem 29 sends and receives commands, device status data, and the like to and from the ground station 132 via the extra small modem 133. The signal received by the RC receiver 28 and the extra small modem 29 is input to the control computer 30. The transmission signal from the control computer 30 is transmitted via the extra small modem 29.

[Control computer configuration]
FIG. 3 is a block diagram showing a schematic configuration of the control computer 30.
The control computer 30 executes a predetermined program (software).

The control computer 30 has a main control system 31, an attitude control rule 32, a guidance rule 33, a navigation rule 34, and an automatic transition control rule 35.
The main control system 31 switches the control axis when the tilt angle is changed. Manual input is possible to the main control system 31.
According to the attitude control rule 32, the main maneuvering system 31 is operated so as to keep the pitch and roll angle of the aircraft 36 at the command values with respect to the desired pitch and roll attitude commands. Pitch and roll attitude commands can be input to the attitude control rule 32 via the remote control device (propo) 131.
The guidance rule 33 captures and processes the tilt angle of the wing 11 and the sensor signal (the detection result of the motion of the aircraft 36) from the aircraft 36, makes it available in the guidance rule 33, and makes these available signals and speed target commands. , Generates commands necessary for maneuvering the aircraft 36 in response to the elevating rate command and the nose orientation command. Rule 34 generates speed target commands, lift rate commands, and heading commands according to the desired flight path and speed. The guidance rule 33 and the navigation rule 34 enable automatic program flight.

The automatic transition control rule 35 executes automatic transition control of the tilt angle of the wing 11 corresponding to the transition flight range from vertical takeoff and landing to cruising flight. In the automatic transition control rule 35, the current speed value and the current tilt angle value are input from the air data sensor 24 and the like, the selected speed (target speed) is input from the navigation rule 34 and the like, and the speed target command and the tilt angle target are input. Output the command. The speed target command is input to the guidance rule 33, and the tilt angle target command is input to the main control system 31. For the current speed value, a signal from an airspeed sensor (not shown) included in the air data sensor 24 connected to the control computer 30 is used (not shown). Further, as the current tilt angle value, a signal from a tilt angle sensor (not shown) connected to the control computer 30 or a current tilt angle command value (output value to the tilt angle servo 21b) is used. This is because even the output value to the tilt angle servo 21b is sufficiently accurate. This eliminates the need for a tilt angle sensor.

As the selection speed (target speed) input to the automatic transition control rule 35, the speed target command in the immediately preceding stage to be input to the guidance rule 33 is used. This speed target command is the target speed value set in the way point on the program flight path input in advance using the ground station software, the target speed value set by the override command from the ground station operator during flight, etc. Given by. Which target speed value is given depends on the automatic flight mode setting selected at that time. For example, when the program flight mode is selected as the automatic flight mode, the target speed value of the waypoint is given. When the speed retention mode by override is selected, the target speed value by the override command is given. In any mode, the speed target command in the immediately preceding stage input to the guidance rule 33 means the speed value targeted by the aircraft 36 at that time.

[Details of automatic transition control law]
FIG. 4 shows an example of the tilt angle change schedule from vertical takeoff to cruising flight of the 4-engine tilt wing type VTOL aircraft 1, and FIG. 5 shows the safe flight range (transition corridor). In FIG. 5, the shaded area indicates the safe flight range, the solid line indicates the standard tilt angle change schedule, and the points on the solid line indicate the tilt angle setting points. These are set values based on the flight performance analysis results using a mathematical model based on wind tunnel test data and the like.
If the 4-engine tilt-wing VTOL aircraft 1 deviates from the safe flight range (see FIG. 5) in terms of aircraft performance while the tilt angle is being changed, safe flight cannot be continued. The automatic transition control rule 35 realizes a tilt angle change schedule from vertical takeoff and landing to cruising flight without deviating from such a safe flight range.

FIG. 6 is a block diagram showing the configuration of the automatic transition control rule 35. FIG. 7 is a table showing an example of the limit value table used in the automatic transition control rule 35. FIG. 8 is a graph corresponding to the value of FIG. 7.
As shown in FIG. 6, the automatic transition control rule 35 includes a speed target command limit value generation unit 351, a speed target command generation unit 352, a tilt angle scheduler 353, and a limit value table 354.

The speed target command limit value generation unit 351 inputs the selected speed (target speed) and the current tilt angle, and generates a speed target command limit value that limits the input target speed according to the current tilt angle. This is to prevent the transition corridor deviation due to a sudden change in the speed target command. As this limit value, the maximum speed (SpdMaxTlt) and the minimum speed (SpdMinTlt) with respect to the tilt angle are used. An example of the maximum speed (SpdMaxTlt) and the minimum speed (SpdMinTlt) with respect to the tilt angle is shown in the limit value table of FIG.

The speed target command generation unit 352 inputs the above speed target command limit value and the current aircraft speed (for example, actually measured airspeed), and generates a speed target command with further restrictions based on the current aircraft speed. do. This is to prevent excessive attitude change and deviation of the transition corridor due to a sudden change in the velocity target command with respect to the current flight speed. As this limit value, the speed target command change limit value is used. An example of the speed target command change limit value is shown in the limit value table of FIG.

The tilt angle scheduler 353 determines whether to generate a tilt angle target command different from the current tilt angle based on the above speed target command, and when generating, selects and generates the corresponding tilt angle target command. For example, in the case of a deceleration transition at the time of landing, when the above speed target command becomes smaller than the deceleration threshold value (Decel Thresh), a tilt angle target command that is one step less than the current tilt angle is selected and generated. .. For example, in the case of an acceleration transition at takeoff, when the above speed target command becomes larger than the acceleration threshold value (Accel Thresh), a tilt angle target command that is one step higher than the current tilt angle is selected and generated. An example of the deceleration threshold value (Decel Thresh) and the acceleration threshold value (Accel Thresh) is shown in the limit value table of FIG. 7 and the graph of FIG.

The limit value table 354 stores the limit values shown as an example in FIG. 7. The limit value is defined by writing in the program in the control computer 30, reading from an external file when the control computer 30 is started, or the like.

FIG. 9 is a flowchart showing the operation of the automatic transition control rule 35.
The automatic transition control rule 35 inputs the selection speed (target speed) (step 801), and determines whether to accelerate or decelerate in order to obtain the input selection speed (step 802). This determination is made, for example, by comparing the current speed with the selected speed. If the current speed <selected speed, it is determined to be acceleration, and if the current speed> selected speed, it is determined to be decelerated. For example, when the current speed is 0 m / s and the selected speed is 30 m / s, it is determined to be acceleration. This acceleration / deceleration determination is used by the tilt angle scheduler 353.

Next, the speed target command limit value generation unit 351 generates a speed target command limit value from the selected speed and the current tilt angle (step 803). The speed target command limit value generation unit 351 reads the maximum speed (SpdMaxTlt) and the minimum speed (SpdMinTlt) according to the current tilt angle from the limit value table 354, and adds a limit to the selected speed according to the current tilt angle. Generate a target command limit. Taking the limit value table of FIG. 7 as an example, even if the selection speed is 30 m / s, when the tilt angle is currently 90 degrees, the speed target command limit value is limited to the range of 0 to 4 m / s.

Next, the speed target command generation unit 352 generates a speed target command from the current aircraft speed (measured value) and the speed command change limit value (step 804). The speed target command generation unit 352 reads the speed target command change limit value according to the current tilt angle from the limit value table 354, and adds or subtracts the speed target command change limit value to the current aircraft speed. Generate. Taking the limit value table of FIG. 7 and the graph of FIG. 8 as an example, when the selection speed is set to, for example, 30 m / s, the tilt angle is currently 90 degrees and the aircraft speed is 1 m / s. Speed target command The speed target command is 2 m / s, which is the sum of the speed target command change limit value of 1 m / s.

The speed target command generated by the speed target command generation unit 352 is output to the guidance rule 33 and the tilt angle scheduler 353 (step 805). The guidance rule 33 generates an attitude and steering angle command for following the speed target command and the altitude command, and finally operates the control surface by the output from the main control system 31.

The tilt angle scheduler 353 determines whether to generate a tilt angle target command different from the current value from the speed target command input from the speed target command generation unit 352 (step 806), and selects the corresponding tilt angle target command when generating. (Step 807). The tilt angle scheduler 353 sets a deceleration threshold value (Decel Thresh) or an acceleration threshold value (Accel Thresh) (determined by the step 802) of the tilt angle scheduler change speed according to the tilt angle from the limit value table 354. Read, compare the speed target command with the deceleration threshold (Decel Thresh) or acceleration threshold (Accel Thresh), and if the speed target command becomes smaller than the deceleration threshold (Decel Thresh) during deceleration, during acceleration When the speed target command becomes larger than the acceleration threshold value (Accel Thresh), the corresponding target tilt angle is selected from the limit value table 354, and the tilt angle target command corresponding to the target tilt angle is generated. Specifically, in the case of a deceleration transition, when the above speed target command becomes smaller than the deceleration threshold value (Decel Thresh), a tilt angle target command that is one step less than the current tilt angle is selected and generated. do. In the case of the acceleration transition, when the above speed target command becomes larger than the acceleration threshold value (Accel Thresh), the tilt angle target command that is one step higher than the current tilt angle is selected and generated. Taking the limit value table of FIG. 7 as an example, when the tilt angle is currently 90 degrees in the acceleration transition, the speed target command is compared with the acceleration threshold (Accel Thresh) of 3 m / s, and the speed is increased. When the target command reaches or exceeds 3 m / s, 80 degrees, which is one step higher than the current tilt angle of 90 degrees, is selected, and a tilt angle target command with a tilt angle of 80 degrees is generated.

The tilt angle target command output from the automatic transition control rule 35 is input to the main control system 31. The main control system 31 generates a tilt angle command and changes the tilt angle to change the form.

The automatic transition control rule 35 performs the above operation until the current aircraft speed reaches the selected speed (step 808).

The above operation will be described with a more specific example.

(1-1) Example of operation ・ After takeoff (hovering state, selection speed = 0 m / s state, tilt angle = 90 degrees, current speed = 0)
-The selection speed = 30 m / s is input (by a human) from the ground station.
-Since the selection speed changed from 0 to 30 m / s, it became acceleration.

(1-2) Speed target command limit ・ The speed target command is 4 m / s depending on the speed target command limit value.
-The speed target command is set to 1 m / s depending on the speed target command change limit value.
・ (Since the current speed is 0 m / s, selection speed + speed target command change limit value = 0 + 1 = 1)
-As a result, the speed target command = 1 m / s.

(1-3) Tilt scheduler-Since the current speed is 0 m / s, the tilt angle remains 90 degrees.
-(Because the acceleration threshold value of the tilt scheduler change speed is 3 m / s. The next tilt angle is not reached until this value (3 m / s) is exceeded.

(2-1) Operation of the aircraft ・ The tilt angle is 90 degrees, and the current speed is accelerated to 1 m / s.
・ (Autopilot according to Guidance Rule 33, the same applies below)
-(Actually, parameters such as current speed and speed target command change continuously (do not increase by 1 m / s), and so on.

(2-2) Speed target command limit / selection speed = 30 m / s (value entered earlier)
-Speed target command The speed target command is 4 m / s depending on the limit value.
-The speed target command is set to 2 m / s depending on the speed target command change limit value.
・ (Since the current speed is 2 m / s, the current speed + speed target command change limit value = 1 + 1 = 2)
-As a result, the speed target command = 2 m / s.

(2-3) Tilt scheduler-Since the current speed is the current speed = 1 m / s, the tilt angle remains 90 degrees. (Because the acceleration threshold of the tilt scheduler change speed is 3 m / s.

(3-1) Operation of the aircraft ・ The tilt angle is 90 degrees, and the current speed is accelerated to 2 m / s.

(3-2) Speed target command limit ・ The speed target command is 4 m / s depending on the speed target command limit value.
-The speed target command is set to 3 m / s depending on the speed target command change limit value.
・ (Since the current speed is 2 m / s, the current speed + speed target command change limit value = 2 + 1 = 3)
-As a result, the speed target command = 3 m / s.

(3-3) Tilt scheduler ・ Since the current speed is 2 m / s, the tilt angle remains 90 degrees.
-(Because the acceleration threshold value of the tilt scheduler change speed is 3 m / s. The next tilt angle is not reached until this value (3 m / s) is exceeded.

(4-1) Operation of the aircraft ・ The tilt angle is 90 degrees, and the current speed is accelerated to 3 m / s.

(4-2) Speed target command limit / selection speed = 30 m / s (value entered earlier)
-Speed target command The speed target command is 4 m / s depending on the limit value.
-The speed target command is 4 m / s due to the speed target command change limit value.
・ (Since the current speed is 3 m / s, the current speed + speed target command change limit value = 3 + 1 = 4)
-As a result, the speed target command = 4 m / s.

(4-3) Tilt scheduler-Current speed is current speed = 3m / s.
・ The tilt angle shifts to 80 degrees at the moment when it exceeds 3 m / s.

(Because the acceleration threshold of the tilt scheduler change speed exceeded 3 m / s.)

(5)) Operation of the aircraft ・ The tilt angle is changed from 90 degrees to 80 degrees, and the current speed is accelerated to 4 m / s.

(6) To the next tilt angle After that, the same operation as above is performed until the current speed = 30 m / s.

[Effect of automatic transition control law]
In the technology developed so far, there are the following problems when flying a 4-engine tilt-wing VTOL aircraft.

As shown in FIG. 10, when the 4-engine tilt wing type VTOL aircraft is an unmanned aerial vehicle, the level of autopilot remains until the automatic program flight, so the acceleration transition and deceleration transition accompanying the change of the tilt angle are remotely controlled. Human operation by a device (propo) or a ground station console is required. Therefore, the safe transition is limited to the visual range.
As a method of changing the tilt angle that does not require human operation, for example, a method of associating a tilt angle change command with a waypoint of the program flight path and setting it in advance can be considered. However, this method does not take into account changes in speed and attitude caused by disturbances such as tilt angle changes and ambient winds. Therefore, during the tilt angle change (transition), this 4-engine tilt-wing VTOL aircraft may deviate from the safe flight range (transition corridor) in terms of aircraft performance, threatening the continuation of safe flight. (Issue 1).
When applying a 4-engine tilt-wing VTOL aircraft as a manned aircraft, the level of autopilot remains until the automatic program flight, so the pilot switches and levers to operate the acceleration transition and deceleration transition that accompany changes in the tilt angle. Operation is required. At the same time, compensation operations related to airspeed and aircraft attitude are also required, so the cockpit workload including other on-board equipment operations and air traffic control communications will be larger than that of fixed-wing passenger aircraft. Therefore, the safety risk increases compared to existing fixed-wing aircraft (Problem 2).
In order to solve these problems, it is necessary to construct an automatic transition control law, but there is no design method for a control law that performs acceleration transition and deceleration transition while preventing deviation from the safe flight range (transition corridor).

On the other hand, by adopting the automatic transition control rule 35 according to the present embodiment, if a desired speed target command is input, the tilt angle is changed, that is, the transition flight is automatically performed, and the form of the aircraft is changed. It is not necessary for the operator or the ground station operator to be involved in the tilt angle change operation corresponding to the above, and the deviation from the flight range is prevented, so that the flight safety is improved. Further, by combining the automatic transition control rule 35 according to the present embodiment with the existing automatic program flight function or the like, the flight task is automated, and the work of the remote operator and the ground station operator (pilot in the case of a manned aircraft). Load is reduced.

[Example Flight Simulation]
For simulation software that simulates the flight motion characteristics of the aircraft (Koji Muraoka, Masayuki Sato, Ryoji Yamamoto, QTW Flight Simulation Program SimQTW (QTW Flight Simulation Program) Ver.1, JAXA PJ0113 (2016/10/12)) , The flight simulation was carried out by incorporating the automatic transition control rule 35 according to the present invention.

Table 1 shows the specifications of the simulated 4-engine tilt-wing VTOL aircraft (FWD02: Fujinokuni Winged Drone). This aircraft is a model of the aircraft used in the flight demonstration.

なお、自動プログラム飛行機能及び自動遷移制御則に関わるプログラム・ソースは、実機搭載用と共通利用可能な構成である。

The program source related to the automatic program flight function and the automatic transition control rule has a configuration that can be commonly used with the actual aircraft.

As the current velocity value, the parameters corresponding to the airspeed sensor signal were calculated in the simulation model, and they were incorporated into the automatic transition control rule 35 part (on the software).
As the current tilt angle, the tilt angle command value (output value to the tilt angle servo) was calculated in the simulation model, and these were incorporated into the automatic transition control rule 35 part (on software).
The speed target command, which is the output from the automatic transition control rule 35, was input to the guidance rule 33, and the tilt angle command was input to the main control system 31.
As the limit value of the automatic transition control rule 35, the parameter value in the limit value table of FIG. 7 was used.
A flight simulation was carried out on the assumption that the aircraft took off manually at a tilt angle of 90 degrees, then transitioned to a tilt of 80 degrees and started advancing, and then the program flight and automatic transition were turned on.

First, we prepared a flight plan for the program flight.
The flight plan is preset in the permutation of waypoints. For each waypoint, the latitude / longitude (or distance and direction from the previous point), target altitude, and target speed of the point are set.

表２及び図１１に飛行シミュレーションに用いた飛行計画を示す。

Table 2 and FIG. 11 show the flight plan used in the flight simulation.

As shown by the white line in the plan view at the bottom of FIG. 11, this flight plan is a route that orbits around the runway while changing the major axis and the minor axis of the rectangle.
The flight simulation was started with a tilt angle of 80 degrees, a program flight ON, and an automatic transition ON.

12 to 15 show the flight trajectory and time history in the horizontal plane of the flight simulation using this flight plan. FIG. 12 is a plan view showing the flight trajectory in the horizontal plane among the flight simulation results. In FIG. 12, the white line indicates the flight plan, and the gray line near the white indicates the flight trajectory. FIG. 13 is a graph showing the time history (parameters in the vertical plane) of the flight simulation results. FIG. 14 is a graph showing the time history (horizontal / directional parameters) of the flight simulation results. FIG. 15 is a graph showing the transition speed (relationship between tilt angle and speed) in the flight simulation results.

With the switching of waypoints, it became as follows.
The airspeed target command is changed.
Along with this, the airspeed changes while the tilt angle is initially fixed.
This speed change is due to the airspeed holding loop in the autopilot mode. Due to this change, when acceleration or deceleration progresses to the tilt angle change range, the tilt angle is automatically changed. The automatic transition function monitors the target airspeed and the actual flight speed, and changes the tilt angle to fly within the safe flight range (corridor).
As for the airspeed, although an overshoot due to the tilt angle change is observed at a maximum of about 2 m / s, it generally follows the command in the acceleration and deceleration transitions.
The flight altitude follows the command generally well for all ascending and descending flight paths.
In the horizontal plane, the flight generally follows the planned route while changing the heading.

From FIG. 15, it can be seen that by using the configuration based on the automatic transition control law according to the present invention, the transition is good while maintaining the safe flight range (corridor).

[Industrial applicability]

(4-engine tilt wing type) As a guidance control system for small unmanned aerial vehicles The 4-engine tilt wing type small unmanned aerial vehicle has vertical takeoff and landing capability and high-speed / long-distance flight capability.
・ Collecting wide-area information in the event of a disaster due to takeoff and landing from a narrow area ・ Detecting fish schools by taking off and landing on the deck of a ship ・ Point-to-point cargo transportation is expected to be applied to missions. Since automatic program flight is the basis for carrying out these missions, the application of the present invention is extremely promising.

(4-engine tilt wing type) As an autopilot system for passenger aircraft The 4-engine tilt wing type passenger aircraft is a new technology that improves convenience such as shortening travel time by operating Door-To-Door as a business aircraft that seats about 6 to 9 people. Expected as. Although such passenger aircraft are operated by pilots, an autopilot system is used from the viewpoint of improving safety by reducing the workload of pilots. When introducing such an autopilot system, it is extremely promising to use the configuration based on the automatic transition control law according to the present invention.
〔others〕
The present invention is not limited to the above-described embodiment, and various modifications and applications are possible within the scope of the technical idea. Implementation by its modification and application also belongs to the technical scope of the present invention.

For example, the above embodiment is an example of applying the present invention to a four-engine tilt airfoil VTOL aircraft, but the present invention is an air vehicle having a portion for transitioning the form, typically the form is stepwise according to the flight speed. It can be applied to an air vehicle having a part to be transitioned to, or an air vehicle whose safety range of the air body itself is changed by changing the form. For example, the present invention can be applied to a landing gear such as a main landing gear or an aircraft such as an aircraft having a flap, a flaperon, a morphing wing, or the like as the relevant portion.

1: 4-engine tilt wing type VTOL machine 11: Wing 21b: Tilt angle servo 35: Automatic transition control rule 36: Aircraft 351: Speed target command limit value generation unit 352: Speed target command generation unit 353: Tilt angle scheduler 354: Limit Value table

Claims (11)

It is a morphological transition control device for an air vehicle that has a part that gradually transitions morphology.
A speed target command range limiting unit that limits the flight speed target command to a range based on the current form with respect to the target flight speed of the flying object.
A morphological transition control device including a morphological transition determining unit that determines whether to transition the morphology from the current morphology to the next stage morphology based on the restricted flight speed target command. The form transition control device according to claim 1.
Further provided is a first limit value table in which the range of the flight speed target command is set for each of the forms of each stage.
The speed target command range limiting unit is a mode transition control device that limits the range of the flight speed target command based on the range of the set flight speed target command. The form transition control device according to claim 1 or 2.
Further, a second limit value table in which a threshold value for whether or not to transition the current form to the next stage form is set for each of the above-mentioned forms of each stage is provided.
The form transition determination unit is a form transition control device that determines whether to transition the form from the current form to the next stage form based on the threshold value. The form transition control device according to claim 3.
The morphological transition control device in which the threshold value is set within the range of the flight speed target command of the morphology. The form transition control device according to claims 1 to 4.
A morphological transition control device further comprising a speed target command change limiting unit that limits changes in a flight speed target command limited to a range based on the current form based on the current flight speed of the flying object. The form transition control device according to claim 5.
Further, a third limit value table in which a limit value for limiting the change of the flight speed target command is set for each of the above forms of each stage is provided.
The form transition determination unit is a form transition control device that limits changes in the flight speed target command based on the limit value. The form transition control device according to claim 5 or 6.
The airspeed sensor has an airspeed sensor.
The morphological transition determining unit is a morphological transition control device that determines the current flight speed based on the detected value detected by the airspeed sensor. The form transition control device according to claim 1 to 7.
The flying object has a servo mechanism for stepwise transitioning the form in response to a transition command.
The form transition determination unit is a form transition control device that determines the current form based on the transition command. A vertical take-off and landing aircraft having the morphological transition control device according to claims 1 to 8.
A vertical take-off and landing aircraft in which the wings that change the tilt angle of the vertical take-off and landing aircraft are the parts where the form is gradually changed. It is a method of controlling the morphological transition of an air vehicle having a part for morphological transition in a stepwise manner.
For the target flight speed of the aircraft, limit the flight speed target command to the range based on the current form,
A morphological transition control method for determining whether to transition the morphology from the current morphology to the next stage morphology based on the restricted flight speed target command. It is a program for controlling the morphological transition of an air vehicle having a part for morphological transition in stages.
A step of limiting the flight speed target command to a range based on the current form with respect to the target flight speed of the aircraft.
A program that causes a computer to perform a step of determining whether to transition the form from the current form to the next stage form based on the restricted flight speed target command.

Images