A method for changing autopilot hold commands in fly-by-wire aircraft

Abstract

This invention discloses a method for changing autopilot hold commands in fly-by-wire aircraft. It includes pitch hold command changes, which, after autopilot activation, involve manipulating the longitudinal trim switch on the control stick to change the pitch angle for autopilot pitch hold mode maintenance. During pitch hold command changes, the desired pitch angle decreases during forward trim and increases during aft trim. This invention conveniently achieves precise attitude / heading changes without adding extra hardware resources.

Description

Technical Field

[0001] This invention relates to the field of aeroelastic design technology for aircraft, and in particular to a method for changing autopilot holding commands in fly-by-wire aircraft. Background Technology

[0002] Pitch and heading hold are the basic modes of autopilot and are used frequently. In normal use, pilots control the autopilot by manipulating the stick / wheel to change the attitude and heading, but this cannot guarantee accurate capture of target values ​​and is time-consuming and laborious; or they can release the stick / wheel and input the desired value through the attitude control input panel to achieve precise control, but this is cumbersome and has poor timeliness. Summary of the Invention

[0003] The purpose of this invention is to provide a method for changing autopilot holding commands in fly-by-wire aircraft. This invention enables convenient and precise attitude / heading changes without adding extra hardware resources.

[0004] Technical Solution. A method for changing autopilot hold commands in a fly-by-wire aircraft, including pitch hold command change, which involves changing the pitch angle of autopilot pitch hold mode hold by manipulating the longitudinal trim switch on the control stick after autopilot is activated; in the pitch hold command change, the desired pitch angle decreases during forward trim and increases during aft trim.

[0005] In the aforementioned method for changing the autopilot hold command of a fly-by-wire aircraft, the pitch hold command change process is as follows: if the single trim time is less than or equal to T seconds, and the trim direction is opposite to the aircraft pitch attitude, then the aircraft longitudinally adjusts to level and enters level flight, at which point the pitch angle at the initial moment that satisfies the leveling termination condition is maintained.

[0006] In the aforementioned method for changing the autopilot hold command of a fly-by-wire aircraft, if the single trim time is less than or equal to T seconds and the trim direction is the same as the aircraft pitch attitude, the switch operation will not be responded to.

[0007] In the aforementioned method for changing autopilot hold commands in fly-by-wire aircraft, if the single trim time is greater than T seconds, command change is initiated; the desired pitch angle command θ 期望 =θ c +θ p , where θ c Let θ be the pitch angle at time T seconds. p To balance the pitch angle; θ p It is calculated by integrating the balance command after T seconds.

[0008] In the aforementioned method for changing autopilot hold commands in fly-by-wire aircraft, the pitch hold mode pitch angle limit is set to ±θ. 限制 When |θ 期望 | Reaching θ 限制At that time, regardless of whether the balance switch is turned on or off, θ p It will no longer change; at the same time, the maximum change in a single trim pitch angle command is ±θ. 限制 .

[0009] The aforementioned method for changing the autopilot hold command in fly-by-wire aircraft also includes changing the heading hold command. This involves changing the heading angle of the autopilot heading hold mode by manipulating the lateral trim switch on the control stick after the autopilot is activated. When trimming to the left, the desired heading angle is reduced, and when trimming to the right, the desired heading angle is increased.

[0010] In the aforementioned fly-by-wire aircraft autopilot hold command change method, the heading hold command change process is as follows: if the single trim time is less than or equal to T seconds, and the trim direction is opposite to the aircraft roll attitude, then the aircraft leveles laterally and maintains the heading angle at the initial moment that meets the leveling end condition.

[0011] In the aforementioned method for changing the autopilot hold command of a fly-by-wire aircraft, if the single trim time is less than or equal to T seconds and the trim direction is the same as the flight roll attitude, the switch operation will not be responded to.

[0012] In the aforementioned method for changing autopilot hold commands in fly-by-wire aircraft, if the single trim time is greater than T seconds, a command change is initiated, with the desired heading angle command r. 期望 =r c +r p , where r c Let r be the heading angle at time T seconds. p To balance the heading angle; r p It is calculated by integrating the balance command after T seconds.

[0013] In the aforementioned method for changing the autopilot hold command of a fly-by-wire aircraft, the heading angle maintained in the heading hold mode is 0 to 359°; at the same time, the maximum change of a single trim lateral angle command is ±180°.

[0014] Beneficial Effects: This invention provides a method for changing pitch / heading hold commands in fly-by-wire aircraft autopilot. It is simple, quick, and convenient to operate, allowing for desired pitch and heading changes in autopilot mode without taking the pilot's hands off the stick, reducing the pilot's operational burden during multi-tasking. This invention does not require additional hardware resources; it achieves rapid and precise changes to pitch / heading hold commands by reusing the longitudinal / lateral five-position trim switches on the control stick. Furthermore, the command output rate of this invention gradually increases from slow to fast, ensuring no control transients during changes in attitude / heading target values ​​and achieving a smooth transition between these changes. Simultaneously, the reasonable logic design avoids undesirable command changes caused by accidental switch activation or malfunction. Attached Figure Description

[0015] Figure 1Diagram of a five-position vertical and horizontal balancing switch;

[0016] Figure 2 Modify the block diagram for pitch commands;

[0017] Figure 3 Flowchart for changing heading angle command. Detailed Implementation

[0018] Example 1. A method for changing autopilot hold commands in a fly-by-wire aircraft, see [link to example]. Figures 1-3 The pitch / heading control commands can be changed quickly and accurately through the five-position trim switches on the control stick handle.

[0019] When autopilot is not engaged, the longitudinal and lateral trim switches function as basic trim switches. Longitudinal trim corresponds to overload / pitch rate inputs, while lateral trim corresponds to roll rate commands. When autopilot is engaged and in attitude / heading hold mode, the longitudinal and lateral trim inputs do not correspond to overload or angular rate commands; instead, they change the target values ​​for pitch and heading control, as detailed below:

[0020] During longitudinal forward trim, the pitch command gradually decreases at a certain rate compared to the current pitch command; during longitudinal aft trim, the pitch command gradually increases at a certain rate compared to the current pitch command; during lateral right trim, the heading command increases clockwise at a certain rate compared to the current heading command; during lateral left trim, the heading command decreases counterclockwise at a certain rate compared to the current heading command.

[0021] 1) Change of pitch hold command

[0022] The pitch hold command change is achieved by manipulating the longitudinal trim switch on the control stick to change the pitch angle of the automatic driving pitch hold mode. Forward trim aims to decrease the pitch angle, while backward trim aims to increase the pitch angle. The specific logic is as follows:

[0023] a) If the single trim time (measured by the duration of continuous toggling of the trim switch) is less than or equal to T seconds, and the trim direction is opposite to the aircraft pitch attitude (i.e., longitudinal rear trim at pitch angle and longitudinal forward trim at pitch angle), then the aircraft will level out and enter level flight, maintaining the pitch angle at the initial moment that satisfies the leveling termination condition; if the single trim time is less than or equal to T seconds, and the trim direction is the same as the aircraft pitch attitude, then the switch operation will not be responded to.

[0024] b) If the single trimming time is greater than T seconds, initiate command change, with the desired pitch angle command θ. 期望 = "Pitch angle θ at time T seconds" c "+" Adjust the pitch angle θ p (Integral of trim command after T seconds), expect pitch angle command to be updated in real time;

[0025] c) The pitch-holding modal pitch angle limitation threshold is ±θ. 限制 That is, |θ 期望 |≤|θ 限制 |, therefore, when |θ 期望 | Reaching θ 限制 At that time, regardless of whether the balance switch is turned on or off, θ p This will no longer change; and to prevent continuous input of trim pitch angle when the switch is abnormally activated, the maximum change of a single trim pitch angle command is ±θ. 限制 .

[0026] Implementation diagram as follows Figure 2 As shown.

[0027] 2) Heading instruction change logic

[0028] The heading hold command change is achieved by manipulating the lateral trim switch on the control stick to change the heading angle of the autopilot heading hold mode. Left trim aims to decrease the desired heading angle, while right trim aims to increase the desired heading angle. The specific logic is as follows:

[0029] a) If the single trim time is less than or equal to T seconds, and the trim direction is opposite to the aircraft's roll attitude (i.e., lateral left trim when rolling right, and lateral right trim when rolling left), then the aircraft will level laterally and maintain the heading angle at the initial moment that satisfies the leveling termination condition; if the single trim time is less than or equal to T seconds, and the trim direction is the same as the aircraft's roll attitude, then the switch operation will not be responded to.

[0030] b) If the trim time for a single operation is greater than T seconds (regardless of whether the trim direction is the same as the aircraft's roll attitude), initiate a command change, with the desired heading angle command r. 期望 =“The heading angle r at T seconds c "+" Trim heading angle r p "(Integral of the trim command after T seconds), the heading angle command is expected to be updated in real time, so that the rate of change of the heading angle command gradually increases with the increase of trim time;

[0031] c) The heading angle for the heading hold mode is 0 to 359°. To prevent continuous input of trim lateral angle commands when the switch is abnormally turned on, the maximum change of a single trim lateral angle command is ±180°.

[0032] Implementation diagram as follows Figure 3 As shown.

Claims

1. A method for changing autopilot hold commands in a fly-by-wire aircraft, characterized in that, This includes pitch hold command change, which is achieved by manipulating the longitudinal trim switch on the control stick after activating autopilot to change the pitch angle of autopilot pitch hold mode; in pitch hold command change, the desired pitch angle decreases during forward trim and increases during backward trim. The process of changing the pitch hold command is as follows: If the single trim time is less than or equal to T seconds and the trim direction is opposite to the aircraft pitch attitude, the aircraft will level up longitudinally and enter level flight. At this time, the pitch angle at the initial moment that meets the leveling end condition will be maintained. If the single trim time is less than or equal to T seconds, and the trim direction is the same as the aircraft pitch attitude, then the switch operation will not be responded to. If the single trim time exceeds T seconds, the initiation command is changed; the desired pitch angle command is θ. 期望 =θ c +θ p , where θ c Let θ be the pitch angle at time T seconds. p To balance the pitch angle; θ p It is calculated by integrating the balance command after T seconds.

2. The method for changing autopilot hold commands in a fly-by-wire aircraft according to claim 1, characterized in that, Let the pitch-holding mode pitch angle limiting threshold be ±θ. 限制 When |θ 期望 | Reaching θ 限制 At that time, regardless of whether the balance switch is turned on or off, θ p No longer changing; meanwhile, the maximum change in a single trim pitch angle command is ±θ. 限制 .

3. The method for changing autopilot hold commands in a fly-by-wire aircraft according to claim 1, characterized in that, It also includes changes to the heading hold command, which is achieved by manipulating the lateral trim switch on the control stick after the autopilot is activated, thereby changing the heading angle of the autopilot heading hold mode; when the autopilot is adjusted to the left, the desired heading angle is reduced, and when the autopilot is adjusted to the right, the desired heading angle is increased.

4. The method for changing autopilot hold commands in a fly-by-wire aircraft according to claim 3, characterized in that, The process of changing the heading hold command is as follows: If the single trim time is less than or equal to T seconds, and the trim direction is opposite to the aircraft roll attitude, then the aircraft will level laterally and maintain the heading angle at the initial moment that satisfies the leveling end condition.

5. The method for changing autopilot hold commands in a fly-by-wire aircraft according to claim 4, characterized in that, If the single trimming time is less than or equal to T seconds, and the trimming direction is the same as the fly-roll attitude, then the switch operation will not be responded to.

6. The method for changing autopilot hold commands in a fly-by-wire aircraft according to claim 4, characterized in that, If the single trim time exceeds T seconds, initiate a command change, expecting the heading angle command r. 期望 =r c +r p , where r c Let r be the heading angle at time T seconds. p For trim heading angle; r p It is calculated by integrating the balance command after T seconds.

7. The method for changing autopilot hold commands in a fly-by-wire aircraft according to claim 6, characterized in that, The heading angle maintained in heading mode is 0–359°; at the same time, the maximum change in a single trim lateral angle command is ±180°.

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