A flight control instruction generation method for aircraft composite maneuver

Abstract

The present application relates to a kind of flight control instruction generation methods for aircraft compound maneuver, first design the trajectory deflection angle, trajectory inclination angle instruction generation method for aircraft compound maneuver.Then design the calculation method for solving trajectory deflection angle, trajectory inclination angle instruction into inner loop pitch, yaw, roll three channel autopilot input.Through the above method, the automatic execution of complex maneuver of aircraft is realized.The flight control instruction generation method for compound maneuver of the present application can stably and quickly control aircraft to execute various maneuver actions.The method for generating flight control instruction in the present application is simpler, only half loop and loop need to divide the maneuver process into two segments, and the rest of the maneuver does not need to be segmented.The method of the present application can control the automatic completion of complex maneuver of aircraft, including but not limited to S-shaped maneuver, sudden pull-up, oblique pull-up, sudden turn-down, barrel roll, loop, half loop and the like.

Description

Technical Field

[0001] This invention belongs to the field of aircraft control technology and relates to a method for generating flight control commands for complex maneuvers of aircraft. Background Technology

[0002] Based on the maneuvering patterns of aircraft in aerial combat, American scholars proposed a maneuver library containing seven basic maneuvers: 1) maximum acceleration, 2) maximum deceleration, 3) maximum G-force climb, 4) maximum G-force dive, 5) maximum G-force left turn, 6) maximum G-force right turn, and 7) stable flight (all control variables remain unchanged). Compound maneuvers consist of multiple basic maneuvers. During compound maneuvers such as barrel rolls and half loops, the trajectory inclination angle, trajectory deflection angle, and roll angle can reverse by ±180° or ±360°, causing autopilots that rely on angle error feedback to fail. Existing solutions often divide a complete compound maneuver into multiple segments, each a separate basic maneuver, generating flight control commands segment by segment in the form of conditional state transitions. This method is relatively complex to implement, requiring separate design for each compound maneuver, as well as the design of conditions and control laws for maneuver entry and exit.

[0003] Aircraft autopilot systems typically have a two-loop (rate gyroscope, accelerometer) or three-loop (rate gyroscope, pseudo-angle of attack filter, accelerometer) structure, which is simple in structure and highly reliable. However, existing autopilots cannot handle the significant changes in angle error caused by the ±180° or ±360° reversals of trajectory tilt angle, trajectory deflection angle, and roll angle values ​​during large-scale complex maneuvers. Therefore, it is necessary to change the angle feedback calculation method to ensure reliable control of the aircraft's complex maneuvers. Summary of the Invention

[0004] Technical problems to be solved

[0005] To avoid the shortcomings of existing technologies, this invention proposes a method for generating flight control commands for complex maneuvers of aircraft.

[0006] Technical solution

[0007] A method for generating flight control commands for complex maneuvers of aircraft, characterized by the following generation steps:

[0008] Step 1: Generate ballistic tilt angle control command θ based on the designed maneuver. c Ballistic deflection command ψ vc With speed command V c ;

[0009] Step 2: Control the trajectory tilt angle according to the command θ cCalculate the trajectory inclination error Δθ, and use the proportional-derivative (PD) output of the trajectory inclination error as the overload command n in the vertical plane. y2 This enables tracking of ballistic tilt angle commands.

[0010]

[0011] Where: θ is the trajectory inclination angle, k θ k θ For the PD controller gain, [-n ymin ,n ymax ] is the overload instruction n y2 The upper and lower limits;

[0012] The ballistic deflection error Δψ is calculated based on the ballistic deflection command, and the PD output of the ballistic deflection error is used as the overload command n in the horizontal plane. z2 This enables tracking of ballistic deflection commands;

[0013]

[0014] Where: ψ is the current ballistic deflection angle of the aircraft, k ψ , For the PD controller gain, [-n zmax ,n zmax ] is n z2 Upper and lower limits, δ ph To set a small value, we'll use 0.01 (rad) here.

[0015] Step 3: Based on the tilt and turning relationship, apply the overload command n in the vertical plane. y2 and the overload command n in the horizontal plane z2 This is converted into a longitudinal overload instruction n. yc Roll angle command n zc :

[0016] when hour:

[0017]

[0018] when hour:

[0019]

[0020] Calculation to determine the direction of Δγ:

[0021]

[0022]

[0023] Δγ=Δγ-π

[0024] else

[0025] Δγ=Δγ+π

[0026] Wherein: γ c For roll angle control signal, n yc For the overload control signal in the y-direction of the velocity system, n zc For the overload control signal in the y-direction of the velocity system, δ n The set value is a small amount, here it is set to 0.1;

[0027] Step 4: Transfer the longitudinal overload command n yc Roll angle command n zc Inputting the autopilot enabled the aircraft to automatically perform compound maneuvers.

[0028] The maneuvers in step 1 include, but are not limited to: S-shaped maneuvers, rapid pull-up, diagonal pull-up, rapid descent and turn, barrel roll, somersault or half somersault.

[0029] When the maneuver in step 1 is an S-shaped maneuver: a sinusoidal signal is used as the ballistic deflection angle command, and the parameter is the maximum ballistic deflection angle ψ. max The parameters of the sinusoidal signal angular velocity ω and phase ψ0 are calculated according to the following formula:

[0030]

[0031] When the maneuver in step 1 involves a sudden pull-up: the trajectory tilt command is generated using the PID output of altitude, calculated as follows, with the parameter being the target altitude H. des Maximum ballistic inclination angle θ max Initial velocity V0, initial trajectory deflection ψ0, H is the current altitude, k H , k IH The gain of the PID controller; the parameters of the maneuver in step 1 are calculated according to the following formula:

[0032]

[0033] When the maneuver in step 1 involves a diagonal pull-up, the parameter is the desired ballistic inclination angle θ. des And θ des >0, expected ballistic deviation angle ψ des V0 is the initial velocity; the parameters of the maneuver in step 1 are calculated according to the following formula:

[0034]

[0035] The maneuver in step 1 involves a sharp descent and turn, i.e., the aircraft dives and turns simultaneously. When considered as a reverse pull-up, the parameter is the desired ballistic inclination angle θ. desAnd θ des <0, expected ballistic deviation angle ψ des V0 is the initial velocity; the parameters of the maneuver in step 1 are calculated according to the following formula:

[0036]

[0037] When the maneuver in step 1 is a barrel roll: A barrel roll is when the aircraft moves at a constant velocity 'a' along the cylindrical axis, with a reference straight line as the axis, and performs circular motion of radius 'b' on the projection of the cylinder's base. The parameters are: barrel roll angular velocity ω, dx is the forward velocity along the axis, dy is the vertical component of the velocity projected onto the cylinder's base, dz is the horizontal component of the velocity projected onto the cylinder's base, ψ0 is the initial ballistic deflection angle, and V0 is the initial velocity. The parameters of the maneuver in step 1 are calculated according to the following formula:

[0038]

[0039] When the maneuvering action in step 1 involves a loop or half-loop maneuver, the flight control command generation method is divided into two segments, along with the state transition conditions between the two segments. The flight control command refers to the trajectory deflection angle ψ. c Ballistic tilt angle command θ c ;

[0040] The term "half-loop" refers to the aircraft rolling 180° at the highest point of a loop maneuver, recovering to a level flight attitude, at which point the aircraft's heading is opposite to that when entering the loop; the ballistic inclination angle θ is defined as... Above, Δθ is given as the control variable; that is, θ c =Δθ + θ; After the action begins, Δθ is set to a constant value of 30°; The parameters of the maneuvering action in step 1 are calculated according to the following formula:

[0041]

[0042] Once the maneuver satisfies the condition that the ballistic deviation angle is opposite to the initial value and the ballistic inclination angle is 0, change to level.

[0043] The aircraft was controlled to level in advance, with θ c As a basis for judgment, the parameters of the maneuvering action in step 1 are calculated according to the following formula;

[0044] If|θ c |<δ jd1 AND cos(ψ-ψ0)<-1+δ jd2

[0045] then:

[0046]

[0047] δjd1 δ jd2 The value is set to a small amount, here it is set to 0.01 (rad).

[0048] When the maneuver in step 1 is a loop: a loop maneuver is when the aircraft continuously pulls up, draws a circle in the vertical plane, and recovers in a level flight attitude.

[0049] The loop maneuver is divided into two parts, marked by passing the top of the loop:

[0050] The first segment is the same as the half-somersault, using a fixed Δθ as input, but without exiting when passing the top of the somersault, and proceeding to the next segment. The parameters of the motorized action in step 1 are calculated according to the following formula:

[0051]

[0052] The second stage of control logic is the same as the first stage, and the parameters of the maneuvering action in step 1 are calculated according to the following formula:

[0053] If|θ c |<δ jd1 AND cos(ψ-ψ0)<-1+δ jd2

[0054] then:

[0055]

[0056] When θc is near 0 and ψ is in the same direction as ψ0, the maneuver is recovered in a level flight attitude. The parameters of the maneuver in step 1 are calculated according to the following formula:

[0057] If|θ c |<δ jd1 AND cos(ψ-ψ0)>1-δ jd2

[0058] then:

[0059]

[0060] Beneficial effects

[0061] This invention proposes a flight control command generation method for complex maneuvers of aircraft. First, it designs a method for generating ballistic deflection and inclination commands for complex maneuvers. Then, it designs a calculation method to convert the ballistic deflection and inclination commands into inputs for the inner-loop pitch, yaw, and roll three-channel autopilot. Through these methods, the aircraft can automatically execute complex maneuvers.

[0062] The flight control command generation method for compound maneuvers of this invention can stably and quickly control an aircraft to perform various maneuvers. Mainstream methods typically divide compound maneuvers into multiple segments (more than three), each with a different flight control command generation method. Mainstream methods require separate design for each maneuver, necessitating the adjustment of numerous parameters and resulting in a huge workload. The method for generating flight control commands in this invention is much simpler; only half-loops and loops require dividing the maneuver process into two segments, while other maneuvers do not require segmentation. The method of this invention can control an aircraft to automatically complete compound maneuvers including but not limited to S-shaped maneuvers, pull-ups, angled pull-ups, descents with sharp turns, barrel rolls, loops, and half-loops. Attached Figure Description

[0063] Figure 1 The flight control command generation method forms a closed-loop system with the aircraft autopilot and aircraft dynamics;

[0064] Figure 2 Steps for generating flight control commands;

[0065] Figure 3 The trajectory of the aircraft in the example of a rapid climb maneuver, with the red arrow indicating the direction of the aircraft's y-axis (defined as the direction perpendicular to the aircraft's axis on the longitudinal plane of symmetry).

[0066] Figure 4 The state changes of the aircraft in the embodiment of the rapid climb maneuver;

[0067] Figure 5 The state changes of the aircraft in the embodiment of the rapid climb maneuver. Detailed Implementation

[0068] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

[0070] The specific implementation of the present invention will be explained using the F-16 fighter jet performing a rapid pull-up maneuver as an example.

[0071] Step 1, Ballistic Inclination Angle Command. The calculation method for the ballistic deflection angle command is as follows:

[0072] Pull-up: A pull-up refers to an aircraft entering and exiting a high-angle climb with significant G-forces. Because fighter jets generally have asymmetrical aerodynamic shapes, negative angles of attack generate relatively little aerodynamic force, so directly nose-down to recover from a climb takes a long time. For larger climb maneuvers, a common practice is to roll 180° near the given altitude before pulling back to level off. The entire pull-up process can be divided into three phases: the entry phase, the straight climb phase, and the exit phase. The calculation method is as follows, with the parameter being the target altitude H. des Maximum ballistic inclination angle θ max

[0073]

[0074] Step 2, as follows Figure 2 As shown, the ballistic deflection command ψ vc Ballistic tilt angle command θ c The solution is a normal overload command n. y2 ,n z2 .

[0075] During flight, the pilot controls the aircraft's pitch (up and down) by pulling the stick or pushing it back and forth according to the required ballistic angle, generating overload in the vertical plane and changing the aircraft's trajectory angle. The actual aircraft angle and the pilot's control form a feedback loop. The PD output of the trajectory angle error is used as the overload command in the vertical plane to track the trajectory angle command. The differential term can achieve an early correction effect. The formula is as follows:

[0076]

[0077] Where θ c For the desired trajectory inclination angle, n y2 Overload is required in the y-direction of the ballistic system (vertical plane normal overload).

[0078] The PD output of the ballistic deflection angle error is used as the overload command in the horizontal plane to track the ballistic deflection angle command. The differential term can achieve the effect of early correction.

[0079]

[0080] Where ψ c For the desired heading angle, n z2 Overload is required in the z-direction of the ballistic system (horizontal plane normal overload).

[0081] When θ crosses 90°, ψ v The value of Δψ is flipped (changed by 180°). Therefore, calculate Δψ. v When this is the case, values ​​near ±180° are considered to be values ​​near 0°. This can be achieved using the periodicity of the sine function and its approximation property near kπ:

[0082] If | sin(ψ c -ψ)|<δ ph AND|ψ c -ψ|>1

[0083] then:

[0084] Δψ=sin(ψ c -ψ)

[0085] δ ph The set value is a small amount, which is 0.01 here.

[0086] Step 3, set the ballistic inclination angle and ballistic deviation angle commands n y2 ,n z2 Based on the tilt-turn relationship, it is converted into a longitudinal overload command n yc Roll angle command γ c ;

[0087] Bank to turn (BTT) involves increasing the aircraft's roll angle during a turn, ensuring the aircraft's y-axis always points in the direction requiring overload, thus achieving a sideslip-free turn. The BTT controller calculates the required overload in the y and z directions of the ballistic system, and then calculates the roll angle command and longitudinal overload command. The formulas are as follows:

[0088] γ c =-atan2(n z2 ,n y2 )

[0089]

[0090] n zc =0

[0091] To prevent n y2 n z2 When crossing near 0, it causes γ c Significant, high-frequency flipping. y2 n z2 When both are relatively small, the tilt angle remains constant. At this time, the total required overload of the aircraft is small, and it is approximately in a free fall state. Therefore, the direction of the overload is meaningless and can be ignored.

[0092]

[0093] Δγ=γ c -γ=0

[0094]

[0095] n zc =0

[0096] γ c For roll angle control signal, nyc For the overload control signal in the y-direction of the velocity system, n zc This is the overload control signal in the y-direction of the velocity system. δn is a small value that can be set to 0.1.

[0097] When γ c When -γ exceeds ±180°, the reverse rotation will cover less angle (for example, the difference between +150° and -170° is +320°, while the reverse rotation only requires -40°). Therefore, in this case, the feedback roll angle error Δγ needs to be recalculated.

[0098]

[0099]

[0100] Δγ=γ c -γ-π

[0101] else

[0102] Δγ=γ c -γ+π

[0103] Step 4, take the longitudinal overload command n obtained in the previous step. yc Roll angle command γ c Input the aircraft autopilot.

[0104] Autopilots include a pitch channel longitudinal overload three-loop autopilot, a yaw channel three-loop lateral overload autopilot, and a roll channel two-loop roll angle autopilot.

[0105] The longitudinal overload three-loop autopilot takes the longitudinal overload command as input n yc The elevator deflection command is output. This enables fast and stable tracking of longitudinal overload signals.

[0106] The lateral overload three-loop autopilot takes 0 as input and the rudder deflection angle δr command as output. It can stabilize and suppress lateral overload when the aircraft is making a banked turn or encountering crosswinds.

[0107] The two-loop roll angle autopilot takes the roll angle error Δγ command as input and the aileron deflection angle command δa as output, achieving fast and stable tracking of the desired roll angle.

[0108] like Figure 4 As shown, the aircraft pulls up at a large angle to climb, first flips 180° near the target altitude, then pulls up to reduce the trajectory angle, and after approaching level, flips 180° again to return to level flight.

[0109] It must be noted that in any of the above embodiments, the methods are not necessarily executed in sequence according to the sequence number. As long as it cannot be inferred from the execution logic that they must be executed in a certain order, it means that they can be executed in any other possible order.

[0110] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for generating flight control commands for complex maneuvers of aircraft, characterized in that... The generation steps are as follows: Step 1: Generate ballistic tilt control commands based on the designed maneuvers. Ballistic deflection command With speed command ; Step 2: Control the trajectory angle according to the instructions Calculate the ballistic inclination error The proportional-derivative (PD) output of the ballistic inclination angle error is used as the overload command in the vertical plane. This enables tracking of ballistic tilt angle commands. in: For the trajectory inclination angle, , For PD controller gain, Overload command The upper and lower limits; Calculate the ballistic deviation angle error based on the ballistic deviation angle command. The PD output of the ballistic deviation angle error is used as the overload command in the horizontal plane. This enables tracking of ballistic deflection commands; in: This represents the aircraft's current ballistic deflection angle. , For PD controller gain, for Upper and lower limits, For the set small quantity; Step 3: Based on the tilt and turning relationship, apply the overload command in the vertical plane. and overload commands in the horizontal plane Transformed into a longitudinal overload command Roll angle command : when hour: when hour: Sure Direction calculation: when At that time, if ,but ,otherwise ; in: For roll angle control signal, For overload control signal in the y-direction of the velocity system, For overload control signal in the y-direction of the velocity system, For the set small quantity; Step 4: Transfer the longitudinal overload command Roll angle command Inputting the autopilot enabled the aircraft to automatically perform compound maneuvers.

2. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: The maneuvers in step 1 include, but are not limited to: S-shaped maneuvers, rapid pull-up, diagonal pull-up, rapid descent and turn, barrel roll, somersault or half somersault.

3. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: When the maneuver in step 1 is an S-shaped maneuver: a sinusoidal signal is used as the ballistic deflection angle command, and the parameter is the maximum ballistic deflection angle. angular velocity of sinusoidal signal Initial ballistic deflection The parameters of the maneuvering action in step 1 are calculated according to the following formula: ， This is the initial velocity.

4. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: When the maneuver in step 1 involves a sudden pull-up: the trajectory tilt command is generated using the PID output of altitude, calculated as follows, with the parameter being the target altitude. Maximum ballistic inclination angle Initial velocity Initial ballistic deflection H is the current height. , , The gain of the PID controller; the parameters of the maneuver in step 1 are calculated according to the following formula: 。 5. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: When the maneuver in step 1 involves a diagonal pull-up, the parameter is the desired ballistic inclination angle. and >0, expected ballistic deflection , The initial velocity; the parameters of the maneuver in step 1 are calculated according to the following formula: 。 6. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: The maneuver in step 1 involves a sharp descent and turn, i.e., the aircraft dives and turns simultaneously. When considered as a reverse pull-up, the parameter is the desired ballistic inclination angle. and <0, expected ballistic deflection , The initial velocity; the parameters of the maneuver in step 1 are calculated according to the following formula: 。 7. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: When the maneuver in step 1 is a barrel roll: a barrel roll is when the aircraft moves at a constant speed 'a' along the cylindrical axis with a reference straight line as the axis, and performs a circular motion with a radius of 'b' on the projection of the bottom surface of the cylinder, with the parameter being the barrel roll angular velocity. , Forward speed along the axis, The vertical component of the velocity projected onto the base of the cylinder. The horizontal component of the velocity projected onto the base of the cylinder. For the initial ballistic deflection angle, The initial velocity; the parameters of the maneuver in step 1 are calculated according to the following formula: 。 8. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: When the maneuvering action in step 1 involves a loop or half-loop maneuver, the flight control command generation method is divided into two segments, along with the state transition conditions between the two segments. The flight control command refers to the trajectory deflection angle. Ballistic tilt angle command ; The term "half-loop" refers to the aircraft rolling 180° at the highest point of a loop maneuver, recovering to a level flight attitude, at which point the aircraft's heading is opposite to that when entering the loop; ballistic inclination angle. Defined in Above, given As a control variable; that is After the action begins, set... The constant value is set to 30°; the parameters of the maneuvering action in step 1 are calculated according to the following formula: Once the maneuver satisfies the condition that the ballistic deviation angle is opposite to the initial value and the ballistic inclination angle is 0, change to level. To level the aircraft in advance, As a basis for judgment, the parameters of the maneuvering action in step 1 are calculated according to the following formula; if ,but ; in: The initial velocity, Initial ballistic deflection, , The set value is a small amount, set to 0.01 rad.

9. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: When the maneuver in step 1 is a loop: a loop maneuver is when the aircraft continuously pulls up, draws a circle in the vertical plane, and recovers in a level flight attitude. The loop maneuver is divided into two parts, marked by passing the top of the loop: The first section is the same as the half somersault, using a fixed... The input is used, but the exit is not changed when passing the top of the somersault, and the next segment is entered. The parameters of the motor action in step 1 are calculated according to the following formula: The second stage of control logic is the same as the first stage, and the parameters of the maneuvering action in step 1 are calculated according to the following formula: if ,but ; when Near 0, and When the direction is the same, the aircraft recovers in a level flight attitude. The parameters of the maneuver in step 1 are calculated according to the following formula: if ,but ; in: The initial velocity, Initial ballistic deflection, , The set value is a small amount, set to 0.01 rad.

10. The method for generating flight control commands for complex maneuvers of aircraft according to claim 1, characterized in that: The small amount Set to 0.01 rad. Set it to 0.1.

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