An automatic landing control method and control system for aircraft

Abstract

This invention pertains to automatic flight control technology, specifically relating to an automatic landing control method and control system for an automatic flight control system. Automatic landing technology is an extension of the approach mode function of modern transport aircraft automatic flight control systems. The automatic landing control method of this invention includes parallel execution of longitudinal mode logic and lateral mode logic. The longitudinal mode logic includes glide slope mode, leveling mode, and low nose mode, while the lateral mode logic includes localizer mode and runway alignment mode. This allows the aircraft to automatically execute the landing procedure without pilot intervention, automatically guiding the aircraft along the glide slope and localizer and aligning it with the runway until touchdown. This reduces the possibility of human error and minimizes the occurrence of safety accidents.

Description

Technical Field

[0001] This invention belongs to the field of automatic flight control technology, specifically relating to an automatic landing control method and control system for an automatic flight control system. Background Technology

[0002] Approach mode is a functional mode of the automatic flight control system for transport aircraft. This mode can automatically control the aircraft to approach the airport runway along a predetermined glide slope and heading path, and switch to manual control at the decision altitude (the minimum landing altitude for CAT II is 30 meters), whereby the pilot continues to complete the landing.

[0003] With the development of technology, people hope that aircraft can be more intelligent and have a higher level of automation, and be able to continue to descend after approaching to a height of 30 meters until touchdown and taxiing on the runway. We define this technology as automatic landing technology.

[0004] Therefore, automatic landing technology is an extension of the approach mode function of the automatic flight control system of modern transport aircraft. It is generally used at airports with low visibility, such as in foggy or snowy weather, when visual landing by the pilot is insufficient to meet safety requirements. The system needs to provide the aircraft with a reliable approach and landing channel based on landing instrument signals, automatically complete the trajectory and speed control during the landing phase, reduce the pilot's workload, and provide automatic control from approach to taxiing (deceleration to safe taxiing speed). Summary of the Invention

[0005] The purpose of this invention is to propose a control method and control system for automatic aircraft landing, which allows the pilot to automatically execute the landing procedure without intervention. It can automatically guide the aircraft along the glide slope and localizer and align it with the runway until the aircraft touches down. This can reduce the possibility of human error and reduce the occurrence of safety accidents.

[0006] This invention proposes an automatic landing control method for aircraft, which includes parallel execution of longitudinal mode logic and lateral mode logic, wherein...

[0007] The vertical pattern logic includes the following steps:

[0008] S1.1 Glide slope mode

[0009] Capture and track GS deviation signals to guide the aircraft down the glide path centerline to an altitude of X1 above the ground;

[0010] S1.2 Flattening Mode

[0011] When the aircraft reaches an altitude of X1, perform a maneuver to reduce the aircraft's vertical speed to a safe landing speed and control the aircraft to touch down with the main landing gear.

[0012] S1.3 Low nose mode

[0013] Control the aircraft's nose to turn downwards and gently bring the nose landing gear into contact with the runway;

[0014] The lateral mode logic includes the following steps:

[0015] S2.1 Course Mode

[0016] Capture and track LOC deviation signals to guide the aircraft to glide along the heading centerline to an altitude of X2 above the ground;

[0017] S2.2 Alignment with Runway Mode

[0018] When the aircraft reaches an altitude of X2, align the aircraft's heading with the runway, align the nose with the runway centerline, and keep the wings level until the nose landing gear touches down.

[0019] Advantageously, step S1.1 includes two stages: the first stage is when the aircraft's altitude is greater than or equal to 70 meters, and the second stage is when the aircraft's altitude is less than 70 meters but greater than or equal to 15 meters.

[0020] Favorably, the control rate in the first phase was:

[0021]

[0022] The control rate in the second phase was:

[0023]

[0024] Where, n zc For normal overload command, η is the glide slope angle deviation, and D X D is the straight-line distance from the aircraft to the beacon, and H is the horizontal distance from the aircraft to the beacon. RA γ is the radio altitude, and γ is the flight path inclination. γ is the differential signal of the flight path inclination angle. g K is the angle of the glide slope beam centerline. γ , K η Both are proportionality coefficients.

[0025] Advantageously, the control law for step S1.2 is:

[0026]

[0027]

[0028] in, To level the target's vertical velocity, The vertical velocity is given by ΔH, and the height above the ground is given by ΔH. For the landing speed, K d , This is the proportionality coefficient.

[0029] Advantageously, the control law for step S1.3 is:

[0030]

[0031] Where, θ g Let K be the target pitch angle, θ be the pitch angle, and K be the target pitch angle. θ This is the proportionality coefficient.

[0032] Advantageously, step S2.1 includes an initial capture and tracking phase, as well as an end-of-pipe tracking phase.

[0033] Advantageously, the control rate during the initial capture and tracking phases is:

[0034] p c =K φ φ+K p p+K ψ (ψ RH -ψ)+K ξ Dtanξ

[0035] The control rate during the end-of-pipe tracking phase is:

[0036] p c =K φ φ+K p p+K ξ Dtanξ

[0037] Where, ψ RH ψ is the runway heading, ψ is the aircraft heading, and p c This is the roll rate command, where ξ is the LOC deviation, φ is the roll angle, p is the roll rate, and K is the angular velocity. φ K p K ψ K ξ2 K ξ This is the corresponding proportionality coefficient.

[0038] Advantageously, the control rate of step S2.2 is:

[0039] p c =K φ (φ g -φ)+K p p

[0040] N y =K y (ψ RH -ψ)

[0041] Where, φ g For the target roll angle, Ny For rudder commands, K y This is the proportionality coefficient.

[0042] This invention also proposes an automatic landing control system for aircraft, which is embedded in the flight control system. The system includes a glide slope mode unit, a leveling-off mode unit, a nose-down mode unit, a localizer mode unit, and a runway alignment mode unit. The glide slope mode unit, leveling-off mode unit, and nose-down mode unit control the longitudinal mode logic of the aircraft, while the localizer mode unit and runway alignment mode unit control the lateral mode logic. The two logics are executed in parallel.

[0043] The glide slope modal unit captures and tracks the GS deviation signal, guiding the aircraft to glide along the glide slope centerline to an altitude of X1 above the ground.

[0044] When the aircraft reaches an altitude of X1, the flattening mode unit performs a maneuver to reduce the aircraft's vertical descent speed to a safe landing speed and controls the aircraft to touch down with the main landing gear.

[0045] The low nose modal unit controls the aircraft nose to turn downwards and makes the nose landing gear gently contact the runway.

[0046] The localizer modal unit captures and tracks the LOC deviation signal, guiding the aircraft to glide along the localizer centerline to an altitude of X2 above the ground.

[0047] When the aircraft reaches an altitude of X2, the runway alignment mode unit aligns the aircraft's heading with the runway, aligns the nose with the runway centerline, and keeps the wings level until the nose landing gear touches the ground.

[0048] Advantageously, the control law of the glide slope mode unit is:

[0049] When the aircraft's altitude is greater than 70 meters,

[0050]

[0051] When the aircraft's altitude is less than 70 meters and greater than or equal to 15 meters above the ground...

[0052]

[0053] Where, n zc For normal overload command, η is the glide slope angle deviation, and D X D is the straight-line distance from the aircraft to the beacon, and H is the horizontal distance from the aircraft to the beacon. RA γ is the radio altitude, and γ is the flight path inclination. γ is the differential signal of the flight path inclination angle. g K is the angle of the glide slope beam centerline. γ , K η Both are proportionality coefficients;

[0054] The control law for the flattened modal unit is:

[0055]

[0056]

[0057] in, To level the target's vertical velocity, The vertical velocity is given by ΔH, and the height above the ground is given by ΔH. For the landing speed, K d , This is the proportionality coefficient;

[0058] The control law for the low-head mode unit is:

[0059]

[0060] Where, θ g Let K be the target pitch angle, θ be the pitch angle, and K be the target pitch angle. θ This is the proportionality coefficient;

[0061] The control law for the course mode unit is:

[0062] Initial capture and tracking phase,

[0063] p c =K φ φ+K p p+K ψ (ψ RH -ψ)+K ξ Dtanξ

[0064] End-of-line tracking phase,

[0065] p c =K φ φ+K p p+K ξ Dtanξ

[0066] Where, ψ RH ψ is the runway heading, ψ is the aircraft heading, and p c This is the roll rate command, where ξ is the LOC deviation, φ is the roll angle, p is the roll rate, and K is the angular velocity. φ K p K ψ K ξ2 K ξ This refers to the corresponding proportionality coefficient;

[0067] The control law for the alignment runway modal unit is:

[0068] p c =K φ (φ g -φ)+K p p

[0069] N y =K y (ψ RH -ψ)

[0070] Where, φ g For the target roll angle, N y For rudder commands, K y This is the proportionality coefficient.

[0071] The beneficial effects of this invention are: the method allows the aircraft to automatically execute the landing procedure without pilot intervention, and can automatically guide the aircraft to fly along the glide slope and localizer and align with the runway until the aircraft touches down. This can reduce the possibility of human error and reduce the occurrence of safety accidents. Attached Figure Description

[0072] Figure 1 This is a flowchart of the automatic landing control method of the present invention;

[0073] Figure 2 This is the block diagram of the automatic landing control logic;

[0074] Figure 3 It is a simulation model of the control law for the glide path mode;

[0075] Figure 4 It is a simulation model of the control law for flattening modes;

[0076] Figure 5 It is a simulation model of the control law for the low-head mode;

[0077] Figure 6 It is a simulation model of the control law for the course mode;

[0078] Figure 7 It is a simulation model of the control law for the runway mode;

[0079] Figure 8 These are simulation curves of the lateral parameters for automatic landing of an aircraft;

[0080] Figure 9 It is a simulation curve of the longitudinal parameters for automatic landing of an aircraft. Detailed Implementation

[0081] The present invention will now be described in further detail with reference to the accompanying drawings.

[0082] Example 1

[0083] See Figure 1An automatic landing control method for an automatic flight control system includes longitudinal mode logic and lateral mode logic. The longitudinal mode logic includes a glide slope mode, a leveling mode, and a nose-down mode executed sequentially, while the lateral mode logic includes a localizer mode and a runway alignment mode executed sequentially. Each mode has a corresponding control law.

[0084] The functional definitions of each mode are as follows:

[0085] 1) Glide path mode

[0086] The control objective of the glide slope mode is to capture and track the GS deviation signal and guide the aircraft to glide along the glide slope centerline to an altitude of 15 meters above the ground.

[0087] The control law for the glide path mode is:

[0088] When the aircraft's altitude is greater than 70 meters,

[0089]

[0090] When the aircraft's altitude is less than 70 meters above the ground

[0091]

[0092] In the formula, n zc For normal overload command, η is the glide slope angle deviation, and D X D is the straight-line distance from the aircraft to the beacon, and H is the horizontal distance from the aircraft to the beacon. RA γ is the radio altitude, and γ is the flight path inclination. γ is the differential signal of the flight path inclination angle. g K represents the angle of the glide slope beam centerline. γ , K η Both are proportionality coefficients.

[0093] Among them, the glide slope beam centerline angle γ g It should be determined based on the beam emission angle of the airport glide slope.

[0094] K η Dsinη needs to be reasonably limited to prevent the aircraft from pitching up when it captures the glide path.

[0095] Furthermore, the control law for the glide slope mode is segmented based on radio altitude, employing different calculation methods. The segmentation method depends on the characteristics of the ground-based glide slope equipment signal; the lower the altitude, the more susceptible the accuracy may be to electromagnetic interference.

[0096] 2) Flattening mode

[0097] When the aircraft is 15m above the ground, the leveling mode will automatically activate. The control objective of leveling mode is to perform a maneuver to reduce the aircraft's descent vertical speed to a safe landing vertical speed (-0.3 to -0.6 m / s), consistent with manual landing maneuvers. Leveling mode will guide the aircraft to touchdown, with a positive pitch angle upon touchdown.

[0098] The control law for the flattened mode is:

[0099]

[0100]

[0101] In the formula, To level the target's vertical velocity, The vertical velocity is given by ΔH, and the height above the ground is given by ΔH. K represents the landing speed. d , This is the proportionality coefficient.

[0102] Horizontal velocity of the target The selection of the appropriate type should take into account the aircraft's structural load and runway length.

[0103] 3) Low nose mode

[0104] The control objective of the low nose mode is to provide rapid and controllable nose-down control of the aircraft and to make the nose landing gear make gentle contact with the runway, consistent with normal manual landing.

[0105] The control law for the low-head mode is:

[0106]

[0107] In the formula, θ g Let K be the target pitch angle, θ be the pitch angle, and K be the target pitch angle. θ This is the proportionality coefficient.

[0108] 4) Courser Mode

[0109] The control objective of the localizer mode is to capture and track the LOC deviation signal and guide the aircraft to glide along the localizer centerline to an altitude of 9 meters above the ground.

[0110] The control law for the course mode is:

[0111] Initial capture and tracking phase,

[0112] p c =K φ φ+K p p+K ψ (ψ RH -ψ)+K ξ Dtanξ

[0113] End-of-line tracking phase,

[0114] p c =K φ φ+K p p+K ξ Dtanξ

[0115] In the formula, ψ RH ψ is the runway heading, ψ is the aircraft heading, and p c This is the roll rate command, where ξ is the LOC deviation, φ is the roll angle, p is the roll rate, and K is the angular velocity. φ K p K ψ K ξ2 K ξ This is the corresponding proportionality coefficient.

[0116] 5) Alignment with runway mode

[0117] The runway alignment mode will automatically activate when the aircraft is 9 meters off the ground. The control objective of the runway alignment mode is to align the aircraft's heading with the runway in crosswinds and to be able to taxi along the runway centerline after touchdown. This mode uses rudder control to align the nose with the runway centerline and keep the wings level.

[0118] The control law for the runway alignment mode is:

[0119] p c =K φ (φ g -φ)+K p p

[0120] N y =K y (ψ RH -ψ)

[0121] In the formula, φ g For the target roll angle, N y For rudder commands, K y This is the proportionality coefficient.

[0122] When implementing the automatic landing control method, it should be determined at all times whether the onboard equipment has automatic landing capability; otherwise, the automatic landing will be disconnected.

[0123] In the control law of each mode, each proportional coefficient should be reasonably selected according to the control law of the aircraft's main flight control internal loop and the characteristics of the aircraft. Each input signal should be filtered to eliminate noise in the signal.

[0124] This method can be integrated into the automatic flight control system as a function to complete the automatic control of automatic landing.

[0125] Example 2

[0126] This embodiment uses the following steps to verify the automatic landing control method:

[0127] Step 1: Use mathematical simulation software such as Matlab / Simulink / Stataflow to build simulation models for each control law.

[0128] Based on the above control law algorithms, a discretized control law simulation model was established (see below). Figures 3-7 In the control law simulation model, the control law output is also limited. According to the glide slope control law parameters selected in this embodiment, see Table 1, leveling control law parameters, nose-down control law parameters, heading control law parameters, and runway alignment control law parameters.

[0129] Table 1. Glide slope control law parameters

[0130] Table 2 Parameters of the Flattening Control Law

[0131] Table 3 Low-noise control law parameters

[0132]

[0133]

[0134] Table 4. Parameters of the Course Control Law

[0135] <![CDATA[K φ ]]> 1 <![CDATA[K p ]]> 0 <![CDATA[K ξ ]]> 0.005 <![CDATA[K ψ ]]> 1.1

[0136] Table 5. Parameters of the runway control law

[0137] <![CDATA[K φ ]]> 1 <![CDATA[φ g ]]> 0 <![CDATA[K p ]]> 0.58 <![CDATA[K y ]]> 7.5 <![CDATA[ψ g ]]> 263

[0138] Step 2) Use Matlab / Simulink to build a six-degree-of-freedom full aircraft equation model, main flight control law model, glide slope beacon model, heading beacon model, and autothrottle model;

[0139] Step 3) Set the entire model execution cycle to 0.02 seconds;

[0140] Step 4) Balance the aircraft equation model;

[0141] Step 5) Connect the signals between the models from Step 1) and Step 2), see... Figure 1 .

[0142] Step 6) Set the initial parameters: glide slope angle of 2.75 degrees, airspeed of 75.3 m / s, and altitude of 500 m.

[0143] Step 7) The simulation begins and ends when the aircraft's nose landing gear touches down.

[0144] Simulation curve from Figure 4 As can be seen, when the aircraft approaches the coordinate origin, i.e., the heading beacon, the control effect is stable, with no oscillation, and it can accurately track the runway centerline. This verifies the effectiveness of the method of the present invention.

Claims

1. An automatic landing control method for an aircraft, characterized in that: This method includes parallel execution of vertical mode logic and horizontal mode logic, wherein The vertical pattern logic includes the following steps: S1.1, Glide slope mode The system captures and tracks the GS deviation signal to guide the aircraft down the glide path centerline to an altitude of X1 above the ground. This process consists of two phases: the first phase occurs when the aircraft's altitude above the ground is greater than or equal to 70 meters, and the second phase occurs when the aircraft's altitude above the ground is less than 70 meters but greater than or equal to 15 meters. The control rate in the first phase was: The control rate in the second phase was: in, This is a normal overload instruction. For the glide slope angle deviation, D X Let D be the straight-line distance from the aircraft to the beacon, and let D be the horizontal distance from the aircraft to the beacon. For radio altitude, For the inclination angle of the flight path, The differential signal of the flight path inclination angle. The angle of the glide slope beam centerline. , , Both are proportionality coefficients; S1.2, Flattening Mode When the aircraft reaches an altitude of X1, perform a maneuver to reduce the aircraft's vertical speed to a safe landing speed and control the aircraft to touch down with the main landing gear. S1.3, Low-head mode Control the aircraft's nose to turn downwards and gently bring the nose landing gear into contact with the runway; The lateral mode logic includes the following steps: S2.1, Courser Mode Capture and track LOC deviation signals to guide the aircraft to glide along the heading centerline to an altitude of X2 above the ground; S2.2, Runway Alignment Mode When the aircraft reaches an altitude of X2, align the aircraft's heading with the runway, align the nose with the runway centerline, and keep the wings level until the nose landing gear touches down.

2. The automatic landing control method for aircraft according to claim 1, characterized in that: The control law for step S1.2 is: in, To level the target's vertical velocity, Vertical velocity, Height above the ground For landing speed, , This is the proportionality coefficient.

3. The automatic landing control method for aircraft according to claim 2, characterized in that: The control law for step S1.3 is: in, For the target pitch angle, The pitch angle, This is the proportionality coefficient.

4. The automatic landing control method for aircraft according to claim 1, characterized in that: Step S2.1 includes the initial capture and tracking phase and the end tracking phase.

5. The automatic landing control method for aircraft according to claim 4, characterized in that: The control rate during the initial capture and tracking phase is: The control rate during the end-of-pipe tracking phase is: in, For runway heading, For the aircraft's heading, For roll rate command, For LOC deviation, For roll angle, For the roll rate, , , , , This is the corresponding proportionality coefficient.

6. The automatic landing control method for aircraft according to claim 5, characterized in that: The control rate for step S2.2 is: in, For the target roll angle, For rudder commands, This is the proportionality coefficient.

7. An automatic landing control system for an aircraft, characterized in that: This system is embedded in the flight control system and includes a glide slope mode unit, a leveling-off mode unit, a nose-down mode unit, a localizer mode unit, and a runway alignment mode unit. The glide slope mode unit, leveling-off mode unit, and nose-down mode unit control the aircraft's longitudinal mode logic, while the localizer mode unit and runway alignment mode unit control the lateral mode logic. The two logics are executed in parallel. The glide slope mode unit captures and tracks the GS deviation signal, guiding the aircraft to glide along the glide slope centerline to an altitude of X1 above the ground; the control law of the glide slope mode unit is: When the aircraft's altitude is greater than or equal to 70 meters above the ground When the aircraft's altitude is less than 70 meters and greater than or equal to 15 meters above the ground... in, This is a normal overload instruction. For the glide slope angle deviation, D X Let D be the straight-line distance from the aircraft to the beacon, and let D be the horizontal distance from the aircraft to the beacon. For radio altitude, For the inclination angle of the flight path, The differential signal of the flight path inclination angle. The angle of the glide slope beam centerline. , , Both are proportionality coefficients; When the aircraft reaches an altitude of X1, the flattening mode unit performs a maneuver to reduce the aircraft's vertical descent speed to a safe landing speed and controls the aircraft to touch down with the main landing gear. The low nose modal unit controls the aircraft nose to turn downwards and makes the nose landing gear gently contact the runway. The localizer modal unit captures and tracks the LOC deviation signal, guiding the aircraft to glide along the localizer centerline to an altitude of X2 above the ground. When the aircraft reaches an altitude of X2, the runway alignment mode unit aligns the aircraft's heading with the runway, aligns the nose with the runway centerline, and keeps the wings level until the nose landing gear touches the ground.

8. The automatic landing control system for aircraft according to claim 7, characterized in that: The control law for the flattened modal unit is: in, To level the target's vertical velocity, Vertical velocity, Height above the ground For landing speed, , This is the proportionality coefficient; The control law for the low-head mode unit is: in, For the target pitch angle, The pitch angle, This is the proportionality coefficient; The control law for the course mode unit is: Initial capture and tracking phase, End-of-line tracking phase, in, For runway heading, For the aircraft's heading, For roll rate command, For LOC deviation, For roll angle, For the roll rate, , , , , This refers to the corresponding proportionality coefficient; The control law for the alignment runway modal unit is: in, For the target roll angle, For rudder commands, This is the proportionality coefficient.

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