JPH0569896A - Automatic flight control system - Google Patents

Abstract

PURPOSE:To attain flight in the shortest arrival required time by improving accuracy of reaching a target flight point FTP while substantially reducing a load on control of a pilot. CONSTITUTION:A target roll attitude for turning by a predetermined turn rate toward a flight course to TIP is set from flight information to FTP and from a level of deviation between a flight direction of an airframe and a nose azimuth, and a command for a roll attitude of the airframe to follow up to the target roll attitude is output (step l). After finishing a turn, the roll attitude of the airframe is returned to a horizontal and controlled so as to prevent detaching from the course (step 2). The target roll attitude necessary for turning by the predetermined turn rate toward the flight course to the FTP is set to output the command for the roll attitude of the airframe to follow up to the target roll attitude (step 3). The roll attitude of the airframe is returned to the horizontal in accordance with approaching the predetermined flight course to the target flight point, and the roll attitude is controlled so as to prevent detaching from the predetermined flight course.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic flight control system for automating guided flight to a target flight point (FTP) in an aircraft (helicopter) and reducing the load on a pilot.
(AFCS).

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 11, an automatic flight control system for a helicopter has conventionally operated a pilot to fly to a target flight point based on the direction, distance and information from the navigation device to the target flight point. It is common to do.

[0003]

The conventional automatic flight control system is mainly based on manual pilot operation.
It has the following problems.

(A) The pilot has a large operational load.

(A) The accuracy of reaching the target flight point (FTP) and the time required to reach it greatly depend on the skill of the pilot.

The present invention has been made in view of the above circumstances, and the guidance flight to the target flight point is fully automated to significantly reduce the pilot's operational load and to achieve the target flight point.
It is an object of the present invention to provide an automatic flight control system that makes the accuracy of reaching (FTP) good on average and that enables flight in the shortest required arrival time.

[0007]

SUMMARY OF THE INVENTION The present invention is an automatic flight control system for a helicopter having a navigation function for providing flight information to a target flight point, after the automatic flight mode to the target flight point is engaged and then engaged. The first means to calculate the bank angle from the airspeed at the time of rotation and output the command to make a turn at a predetermined turn rate to the roll servo, after the automatic flight mode is engaged, at the predetermined turn rate When the turn is finished, the command for controlling the roll attitude is output to the roll servo to correct the deviation from the flight course and put it on the flight course up to the prospective turn point before the turn-in point. When the second means, the approach course to the target flight point, is designated, the vehicle turns at a predetermined turn rate toward the approach course to the target flight point after the second means. Command to output to the roll servo the command to return the roll attitude to the horizontal position before FTP on top while correcting the deviation with respect to the approach course to the target flight point after turning. After the control subsystem and the automatic flight mode to the target flight point are engaged, the yaw system control subsystem that outputs the command to execute the balanced turning mode (auto turn coordination mode) to the yaw servo Mode switching between the system, the pitch system subsystem that outputs commands to the pitch servo to maintain the airspeed when the automatic flight mode to the target flight point is engaged, and the roll system control subsystem Equipped with a mode control subsystem, it automatically guides flight from any flight condition to the target flight point. It is a feature.

[0008]

The automatic flight control system according to the present invention controls flight by the following four steps.

(1) Step 1a. The roll system control subsystem uses the flight information to the target flight point FTP input from the navigation function of the aircraft and the size of the deviation between the flight direction of the aircraft and the heading (hereinafter referred to as the drift angle). Therefore, when the approach course to the target flight point FTP is specified, the target roll attitude necessary for turning at the predetermined turn rate toward the predetermined flight course to the turn-in point set by the navigation function is set. The command to set the roll attitude of the machine to follow the target roll attitude is derived and output to the roll servo. When the approach course to the target flight point FTP is not specified, the target flight point FT is used instead of the predetermined flight course to the turn-in point described above.
The same command is output to the roll servo toward the predetermined flight course to P.

B. The yaw system control subsystem is engaged in the auto turn coordination mode, and outputs a command for zeroing the lateral acceleration to the yaw servo.

C. The pitch system control subsystem sets the airspeed when the enroute nab mode is engaged as the target airspeed and derives a command to make the airspeed of the aircraft follow the target airspeed. Output to servo.

D. The mode control subsystem, based on the flight information input from the navigation function method of the aircraft,
It determines whether the approach course to the target flight point FTP is designated or not, and controls the mode switching of the roll system control subsystem.

(2) Step 2 The roll system control subsystem returns the roll posture of the machine body to the horizontal position as it approaches the predetermined flight course after the turning, and controls the roll posture so as not to be separated from the predetermined flight course.

The yaw system control subsystem outputs a command to the yaw servo to enable a balanced turn toward a predetermined flight course.

The pitch system control subsystem outputs a command for maintaining the airspeed to the pitch servo.

The mode control subsystem uses the target flight point F
When the approach course to TP is designated, the turning start anticipation distance for determining the transition to step 3 is derived from the airspeed and the anticipatory turning time constant, and is output to the roll system control subsystem. When the approach course to the target flight point FTP is not designated, the FTP on top is determined.

(3) Step 3 When the approach course to the target flight point FTP is designated, the roll system control subsystem turns at a predetermined turn rate toward a predetermined flight course to the target flight point FTP. The target roll attitude required for the above is set, and a command for causing the roll attitude of the machine body to follow the target roll attitude is derived and output to the roll servo.

The yaw system control subsystem outputs a command to the yaw servo to enable a balanced turn toward a predetermined flight course.

The pitch system control subsystem outputs a command for maintaining the airspeed to the pitch servo.

(4) Step 4 When the approach course to the target flight point FTP is designated, the roll system control subsystem makes the roll attitude of the aircraft horizontal as the predetermined flight course to the target flight point FTP is approached. Roll back and control the roll attitude so as not to leave the flight course.

The yaw system control subsystem outputs a command to the yaw servo for enabling a balanced turn toward a predetermined flight course.

The pitch system control subsystem outputs a command for maintaining airspeed to the pitch servo.

The mode control subsystem makes an FTP-on-top determination based on the flight information input from the navigation function.

As described above, the aircraft (helicopter) is automatically guided to the target flight point FTP from arbitrary flight conditions by the control of steps 1 to 4.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The automatic helicopter flight control system to the target flight point FTP according to the present invention takes the flight route shown in FIG. The control is executed to automatically guide the aircraft to the target flight point FTP.

When the approach course to the target flight point FTP is not designated, the flight route shown in FIG. 2 is taken and the control of steps 1 and 2 is executed to set the aircraft to the target flight point FTP.
Automatically guided flight to.

Details of steps 1 to 4 will be described later.

Therefore, the control system for executing the above flight control is composed of the following subsystems (1) to (4).

(1) A mode control subsystem for switching the mode of automatic flight according to the flight situation.

(2) A roll system control subsystem which outputs a command for controlling the roll attitude to the roll servo so that the aircraft is put on a predetermined flight course.

(3) A yaw system control subsystem that outputs a command for controlling sideslip to the yaw servo so that the roll system control subsystem functions effectively.

(4) A pitch system control subsystem for outputting a command for controlling the flight speed to the pitch servo.

Each of the above subsystems is constructed as shown in FIGS.

FIG. 3 is a block diagram showing the configuration of the on-top determination / turning start determination unit in the mode control subsystem. Turn from the navigation function
The in-point-on-top determination signal is input to the set terminal S of the flip-flop circuit 2 via the -1 signal rise determination circuit 1. This flip-flop circuit 2
Q output signal is taken out as a turn-in-point-on-top signal A15.

When the approach course to the target flight point FTP is designated, the turning start anticipation distance generator 3 generates the turning start anticipation distance STEN using the airspeed UA and the anticipatory turning time constant Cp14. , And to the on / off determination circuit 5 via the minus terminal of the subtractor 4. The output signal of the ON / OFF determination circuit 5 is input to the set terminal S of the flip-flop circuit 7 via the OR circuit 6 together with the output signal of the flip-flop circuit 2. Then, the Q output signal of the flip-flop circuit 7 is output to the roll system control subsystem shown in FIG. 4 as the turn-in start flag A16.

The turn-in point distance from the navigation function is input to the + terminal of the subtractor 4 and also to the -1 signal rise determination circuit 9 via the on / off determination circuit 8. The flip-flop circuits 2 and 7 are reset by the output signal of the -1 signal rise determination circuit 9.

Further, the FTP on-top determination signal from the navigation function is input to the reset terminal R of the flip-flop circuit 11 and the -1 signal rise determination circuit 12
Is input to the set terminal S of the flip-flop circuit 11 via. The output signal of the flip-flop circuit 11 is output as the FTP on-top signal A17.

FIGS. 4 to 8 show the configuration of each part of the roll control subsystem and flight information from the navigation function. FIG. 4 is a lateral guidance control law, FIG. 5 is a drift angle calculation processing part, and FIG. Flight information from the navigation function, FIG. 7 is a nose heading deviation correction processing unit, and FIG. 8 is a roll autopilot control law.

In the lateral guidance control law shown in FIG. 4, the magnetic heading φ is input to the + terminal of the subtractor 21. on the other hand,
Approach course φFTP from the navigation function to the target flight point FTP
And turn-in point TIP approach course direction φ
The TIP is selected by the changeover switch 22 operated by the turn-in start flag A16 from the mode control subsystem shown in FIG. 3, and input to one terminal of the subtractor 21. Various flight information from the navigation function is shown in FIG.

In FIG. 6, RTIP: distance to turn-in point TIP, RFTP: distance to target flight point FTP, θDTIP: turn-in-point course deviation, θDFTP: FTP course deviation, φTIP: Turn-in-point TIP approach course azimuth, φFTP: approach-point azimuth FTP approach target course. Deviation is based on the set course, and each angle is positive in the clockwise direction from the reference axis. In the illustrated example, both θDTIP and θDFTP are negative, φFTP is positive, and φTIP is negative.

In FIG. 4, the output signal φe of the subtractor 21 is input to the adder 23. Further, the drift angle A20 from the drift angle calculation processing unit 20 shown in FIG. 5 is input to the adder 23 via the switch 24. The drift angle calculation processing unit 20 shown in FIG. 5 obtains the drift angle A20 by performing an arithmetic processing of "arctan (VB / UB)" based on the vertical ground speed UB and the horizontal ground speed VB.

Then, in FIG. 4, the output signal of the adder 23 is limited to φeL by the limiter 25, and is further corrected by the heading deviation correction processing unit 26. The signal φeT corrected by the heading deviation correction processing unit 26 is input to the adder 28 via the gain (gain heading scheduler for magnetic heading) 27. The heading deviation correction processing unit 26 is configured as shown in FIG. 7, and details thereof will be described later.

The course deviation θDFTP from the navigation function to the target flight point FTP is input to the gain scheduler 29. Also, the distance R to the target flight point FTP
The FTP is input to the multiplier 30a, the airspeed is input to the multiplier 30a via the speed ratio calculation circuit 31 and the gain switching point speed adjustment circuit 32, and the multiplication result is sent to the gain scheduler 29. In addition, the speed adjusting circuit 3
The output of 2 is input to gain scheduler 34 via multiplier 30b with the distance RTIP to the turn-in point. Further, the course deviation θDTIP to the turn-in point TIP is input to the gain scheduler 34.

The output signals of the gain schedulers 29 and 34 are selected by the changeover switch 33 operated by the turn-in start flag A16, and the gains (coarse deviation proportional gains) 36 and 3 are output via the limiter 35.
Input to 7. The output signal of the gain 36 is the switch 3
8 is input to the fade-in / out circuit 39. Then, the gain 36 and the fade-in / out circuit 3
The output signals of 9 are added by the adder 40, and then input to the bank angle limiter 41 via the adder 28. The air speed UA is input to the bank angle limiter 41 as a bank angle limit value A47 via a rate limiter 42, a gain 43, a function unit 44 of tan ⁻¹ , and a limiter 45. The output signal of the bank angle limiter 41 is output as a reference roll angle shift command A48 via the rate limiter 46.

Therefore, the heading deviation correction processing unit 2
6 is a selector switch 51, 52, 5 as shown in FIG.
It is composed of 3. The changeover switches 51, 52 are provided with changeover contacts a, b, c, and a left turn command constant 54 (B
R31), the nose bearing φeL from the limiter 25 is input to the contact point b, and the right turn command constant 55 (-BR31) is input to the contact point c. The changeover switch 51 closes the contact a when the left turn command A56 (turn-in point) ON is given, and the right turn command A57 (turn-in point) O.
The contact c is closed when N is given, and the contact b is closed otherwise. The signal taken out via the changeover switch 51 is input to the contact a of the changeover switch 53.

On the other hand, in the changeover switch 52, the contact a is closed when the left turn command A58 (FTP) ON is given,
The contact point c is closed when the right turn command A59 (FTP) ON is given, and the contact point b is closed otherwise. The signal extracted via the changeover switch 52 is the changeover switch 53.
Input to contact point b. This changeover switch 53 has the contact b closed when the turn-in start flag A16 is ON,
Otherwise, contact a closes. And the changeover switch 5
The signal extracted via 3 is the corrected heading φe
It becomes T. The above left turn command and right turn command are
As shown in FIG. 7 (b), it is input from the navigation function only while the absolute value of the turning angle θ required to get on the turn-in point course or the FTP course is 90 ° or more.

FIG. 8 shows a roll auto pilot control law in the roll system control subsystem.
As shown in the figure, the roll attitude φ is input to the + terminal of the subtractor 61, the reference roll angle shift command A48 sent from FIG. 4 is input to the − terminal, and the subtraction result is added via the gain 62. Input to the container 63. In addition, the roll rate P is gained (proportional gain) in the adder 63.
64 and 65, and the addition output is the adder 6
6 is input. The output of the subtractor 61 is input to the adder 66 via the gain 67 and the integrator 68. The output of the adder 66 is sent to the roll trim servo as a roll trim shift command A69.

FIG. 9 shows the configuration of the yaw system control servo system. The lateral acceleration Nr is input to the adder 73 via the gain 71 and the integrator 72. Further, the lateral acceleration Nr and the roll rate P are gains 74 and 7, respectively.
It is input to the adder 76 via 5, and the addition output is input to the adder 73. Then, the output signal of the adder 73 is sent to the yaw trim servo as a yaw trim shift command A77.

FIG. 10 shows the configuration of the pitch system control subsystem. The pitch rate q is input to the adder 82 via the gain 81. The pitch attitude angle θ is input to the + terminal of the subtracter 83, and the changeover switch 8
4 is input to the terminal a. A common contact of the changeover switch 84 is connected to the-terminal of the subtractor 83, and is also connected to its own terminal b via a memory 85 for storing the previous value of the cycle calculation process. In the changeover switch 84, the contact a is closed at the time of cyclic trim release, and the contact b is closed at other times. Then, the output of the subtractor 83 is input to the adder 82 via the gain 86.

On the other hand, the airspeed UA is input to the + terminal of the subtractor 87 and the terminal a of the changeover switch 88. The changeover switch 88 has a common contact connected to the-terminal of the subtractor 87, and is also connected to its own terminal b via a memory 89 for storing the previous value of the cycle calculation process. In the changeover switch 88, the contact a is closed at the time of cyclic trim release, and the contact b is closed at other times. Then, the output of the subtractor 87 is input to the adder 82 via the gain 90.

The output of the subtractor 87 is input to the integrator 92 via the gain 91. This integrator 92 is reset by cyclic trim release.
The output of the integrator 92 is the output of the adder 82 and the adder 9
3 is added, and the added output is sent to the pitch trim servo as a pitch trim shift command A95.

Next, the operation of the system of the present invention for carrying out the automatic guided flight shown in FIGS. 1 and 2 will be described. In the automatic flight control system according to the present invention, the following control operations of steps 1 to 4 are executed.

(1) Step 1 Step 1 is an automatic flight mode to the target flight point FTP as shown in FIGS.
Turn from (hereinafter referred to as enroute nab mode)
In-point TIP or the phase until transition to the predetermined flight course to the target flight point FTP.

A. The mode control subsystem shown in FIG. 3 uses the flight information to the target flight point FTP input from the navigation function by each logic circuit, and uses the target flight point FT.
It is judged whether the approach course to P is specified or not.

B. When the roll course control subsystem shown in FIGS. 4 to 8 designates the approach course to the target flight point FTP, the turn-in point T in FIG.
Entry course direction to IP φTIP, distance to turn-in point TIP RTIP, turn-in point TIP
To the desired flight course using the course deviation θDTIP, the left / right turn commands A56, A57 (FIG. 7) and the magnetic heading φ and the drift angle A20 which is the output of the circuit shown in FIG. The circuit shown in FIG. 8 generates a reference roll angle shift command A48 that sets the roll attitude necessary for turning at a predetermined turning rate at the maximum to a limit value A47.
(Roll autopilot control law)
Generate a trim shift command A69.

When the approach course to the target flight point FTP is not specified, the approach course direction φFTP to the target flight point FTP and the distance RFTP to the target flight point FTP in FIG.
Course deviation θDFTP to target flight point FTP
, The left / right turn commands A58, A59 (FIG. 7) and the magnetic heading φ and the output of the circuit shown in FIG. Limit value A4 for the roll posture required to turn at
The circuit shown in FIG. 8 for generating the standard roll angle shift command A48 of 7 (roll autopilot control law)
To generate a roll trim command A69.

C. The yaw system control subsystem shown in FIG. 9 uses the lateral acceleration Nr and the roll rate P to generate the yaw trim shift command A77 for smoothly performing the turning without skidding.

D. The pitch system control subsystem shown in FIG. 10 sets the airspeed UA when the enroute nab mode is engaged as the target airspeed A94, and the pitch for making the airspeed UA of the aircraft follow the target airspeed.・
Trim shift command A95 is generated.

(2) Step 2 In step 2, after the turning is completed, if the approach course to the target flight point FTP is designated as shown in FIG. 1, the turn as shown in FIG.
If you do not specify the approach course to the target flight point FTP during the phase up to in point on top, FT
It means the phase to P on top.

A. In FIG. 3, when the approach course to the target flight point FTP is designated, the mode control subsystem uses the airspeed UA and the anticipatory turning time constant CP14 to turn anticipation by the turning start anticipation distance generation unit 3 Generates the distance STEN, and further flip-flop circuit 7
The turn-in start flag A16 is generated through
Input to the circuit (lateral guidance control law) shown in to switch the mode of the roll system control subsystem.

Then, when the turn-in point TIP is reached, the turn-in-point-on-top is judged by the judging circuit 1, and the turn-in point
The on-top signal A15 is generated.

When the approach course to the target flight point FTP is not designated, the FTP on-top is determined by the determination circuit 12 and the FTP on-top signal A17 is generated.

B. The roll system control subsystem generates a roll trim shift command A69 for controlling the roll attitude A70 in the same manner as the content shown in step 1b according to FIGS. In addition,
When the roll attitude A70 specifies the approach course to the target flight point FTP, the course deviation θDTIP to the turn-in point TIP shown in FIG. 4 is turned.
The distance to the in-point TIP can be gradually moved horizontally by decreasing the distance as it approaches the turn-in point TIP by a function having the parameter RTIP as a parameter. When the approach course to the target flight point FTP is not specified, the course deviation θDFTP to the target flight point FTP shown in FIG. 4 is set to the target flight point FTP.
The distance to the target flight point FTP can be gradually decreased by decreasing the distance RFTP to the target flight point FTP.

Further, when the approach course to the target flight point FTP is designated, the turn-in / start flag A16 input from the mode control subsystem of FIG. 3 is used before the turn-in point TIP. Can make anticipatory turns.

C. The yaw system control subsystem generates the yaw trim shift command A77 for controlling the lateral acceleration Nr according to FIG. 9 in the same manner as the content shown in step 1c.

D. The pitch system control subsystem shown in FIG. 10 is similar to the content shown in step 1 d,
Generates a pitch trim shift command A95 for controlling airspeed UA.

(3) Step 3 In Step 3, as shown in FIG. 1, when the approach course to the target flight point FTP is designated, the turn-in point TIP is reached toward the target flight point FTP after the arrival of the turn-in point TIP. The phase until the end of turning.

A. Roll system control subsystem (Fig. 4 ~
8) is a roll trim shift command for controlling the roll attitude φ (FIG. 8) in the same manner as the content shown in the case of not designating the approach course to the target flight point FTP in step 1b. Generate A69.

B. Yaw system control subsystem (Fig. 9)
Is the yaw trim shift control for controlling the lateral acceleration Nr in the same manner as that described in step 1c.
Generates command A77.

C. Pitch system control subsystem (Fig. 1
0) generates a pitch trim shift command A95 for controlling the airspeed UA in the same manner as the content indicated by d in step 1.

(4) Step 4 Step 4 refers to the phase from the end of turning to the FTP in top when the approach course to the target flight point FTP is designated as shown in FIG.

A. The mode system control subsystem shown in FIG. 3 determines the FTP on-top and generates the FTP on-top signal A17.

B. Roll system control subsystem (Fig. 4 ~
8) shows the target flight point F in step 1b and step 2
A roll trim shift command A69 for controlling the roll posture φ (FIG. 8) is generated in the same manner as the content shown when the TP entry course is not designated.

C. The yaw system control subsystem generates a yaw trim command 13 for controlling the lateral acceleration 11 according to FIG. 9 in the same manner as the content shown in step 1 c.

D. Pitch system control subsystem (Fig. 1
0) generates a pitch trim shift command A95 for controlling the airspeed UA in the same manner as the content indicated by d in step 1.

[0077]

Since the present invention is constructed as described above, it has the following effects.

(1) When the approach course to the target flight point FTP is specified, the anticipatory turn is carried out when turning toward the target flight point FTP so that the target flight point F is reached.
It is possible to improve the accuracy of reaching TP.

(2) Since the enroute nab mode can be engaged depending on whether the approach course to the target flight point FTP is designated or not, the fully automatic guided flight to the target flight point FTP is possible. It is possible.

(3) Since the roll posture during turning can be kept constant, the ride comfort of the pilot is not impaired.

(4) With these, the pilot's operational load can be significantly reduced, and the accuracy of reaching the target flight point FTP and the time required to reach it can be improved on average.

[Brief description of drawings]

FIG. 1 is a flight route diagram when an approach course to a target flight point FTP is designated in an automatic flight control system according to an embodiment of the present invention.

FIG. 2 is a flight route diagram when the approach course to the target flight point FTP is not designated in the embodiment.

FIG. 3 is a block diagram showing a mode control subsystem in the embodiment.

FIG. 4 is a block diagram showing a lateral guidance control law of the roll system control subsystem in the embodiment.

FIG. 5 is a block diagram showing a drift angle calculation process of the roll system control subsystem in the embodiment.

FIG. 6 is an explanatory diagram showing flight information data from a navigation function in the same embodiment.

FIG. 7 is a circuit configuration diagram showing a nose heading deviation correction processing unit of the roll system control subsystem in the embodiment.

FIG. 8 is an explanatory diagram showing a roll autopilot control law of the roll system control subsystem in the embodiment.

FIG. 9 is a block diagram showing a yaw system control subsystem in the embodiment.

FIG. 10 is a block diagram showing a pitch system control subsystem in the embodiment.

FIG. 11 is an explanatory diagram showing a flight path to a target flight point according to a conventional technique.

[Explanation of symbols]

 1,9,12 -1 Signal rising judgment circuit 2,7,11 Flip-flop circuit 3 Turning start anticipation distance generation unit 5,8 ON / OFF judgment circuit 20 Drift angle calculation processing unit 25 Limiter 26 Heading deviation correction processing unit 27 gain (gain scheduler for magnetic heading) 29,34 gain scheduler 31 speed ratio calculation circuit 35 limiter 41 bank angle limiter 42,46 rate limiter

Claims (1)

[Claims] 1. In a flight control system of a helicopter having a navigation function for providing flight information to a target flight point, after the automatic flight mode to the target flight point is engaged, the bank angle is calculated from the airspeed at the time of engagement. When the automatic flight mode is engaged and the turn at the predetermined turn rate is finished, the first means for calculating the command to output to the roll servo the command for turning at the predetermined turn rate,
To the target flight point, the second means to output the command to the roll servo to correct the deviation to the flight course and put it on the flight course until the prospective turning point before the turn-in point is corrected. When the approach course is designated, the command for turning at a predetermined turn rate toward the approach course to the target flight point after the second means is output, and after the turn, the approach to the target flight point is performed. A roll system control subsystem consisting of means for outputting commands to the roll servo to return the roll attitude to the horizontal position before the target flight point on top while correcting the deviation with respect to the course, and the automatic flight mode to the target flight point. After being engaged, the yaw system control system that outputs the command to execute the balanced turning mode to the yaw servo, and the automatic flight to the target flight point above. Arbitrary flight with a pitch subsystem that outputs commands to the pitch servo to maintain the airspeed when the mode is engaged, and a mode control subsystem that switches the mode of the roll system control subsystem An automatic flight control system that automatically guides you from a condition to a target flight point.