Fly-by-wire aircraft autopilot holding instruction changing method

Abstract

The invention discloses a fly-by-wire aircraft autopilot holding instruction changing method. Comprising the following steps of: changing a pitching keeping instruction, namely changing a pitching angle kept in an automatic driving pitching keeping mode by operating a longitudinal trimming switch on a control rod handle after the automatic driving is activated; in the change of the pitch holding command, the desired pitch angle is reduced during the previous trim and is increased during the subsequent trim. According to the method, accurate change of the attitude / course is conveniently realized without adding extra hardware resources.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft aeroelastic design, and in particular to a method for changing automatic piloting instructions of a fly-by-wire aircraft. Background Art

[0002] Pitch and heading hold are the basic modes of autopilot and are used frequently. In normal use, the pilot overrides the autopilot by manipulating the joystick / panel to change the attitude and heading, but it cannot guarantee the accurate capture of the target value, which is time-consuming and laborious; or the pilot releases the joystick / panel and inputs the expected value through the attitude control input panel to achieve precise control, but the operation is cumbersome and time-consuming. Summary of the invention

[0003] The purpose of the present invention is to provide a method for changing the automatic piloting instructions of a fly-by-wire aircraft. The present invention conveniently realizes accurate change of attitude / heading without adding additional hardware resources.

[0004] Technical solution: A method for changing the autopilot hold command of a fly-by-wire aircraft, including a pitch hold command change, which is to change the pitch angle of the autopilot pitch hold mode by manipulating the longitudinal trim switch on the joystick handle after activating the autopilot; in the pitch hold command change, the expected pitch angle decreases during the forward trim and increases during the rear trim.

[0005] In the aforementioned method of changing the hold command of the fly-by-wire aircraft autopilot, the process of changing the pitch hold command is as follows: if the single balancing time is less than or equal to T seconds, and the balancing direction is opposite to the aircraft's pitch attitude, the aircraft will level longitudinally and enter a level flight state, while maintaining the pitch angle at the initial moment that meets the leveling end condition.

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

[0007] In the above-mentioned method for changing the command of the fly-by-wire aircraft autopilot, if the single trim time is greater than T seconds, the command change is initiated; the desired pitch angle command θ 期望 =θ c +θ p , where θ c is the pitch angle at T seconds, θ p is the trim pitch angle; θ p Calculated by integrating the trim commands after T seconds.

[0008] In the above-mentioned fly-by-wire aircraft autopilot hold command change method, the pitch hold mode pitch angle limit threshold is set to ±θ 限制 , when |θ 期望 | Arrival θ 限制When the trim switch is on, θ p No longer changes; at the same time, the maximum change of a single trim pitch angle command is ±θ 限制 .

[0009] The aforementioned method for changing the autopilot holding command of a fly-by-wire aircraft also includes a heading holding command change, which is achieved by operating the lateral trim switch on the joystick handle to change the heading angle maintained in the autopilot heading holding mode after activating the autopilot; when the left trim is used, the desired heading angle decreases, and when the right trim is used, the desired heading angle increases.

[0010] In the aforementioned method of changing the automatic flight control instructions for fly-by-wire aircraft, the process of changing the heading holding instructions is as follows: if the single balancing time is less than or equal to T seconds, and the balancing direction is opposite to the aircraft's roll attitude, the aircraft will level laterally and maintain the heading angle at the initial moment that meets the leveling end condition.

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

[0012] In the above-mentioned method of changing the command of the fly-by-wire aircraft autopilot, if the single trim time is greater than T seconds, the command change is initiated, and the desired heading angle command r 期望 =r c +r p , where r c is the heading angle at T seconds, r p is the trim heading angle; r p Calculated by integrating the trim commands after T seconds.

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

[0014] Beneficial effects: The present invention provides a method for changing the pitch / heading hold command of an autopilot of a fly-by-wire aircraft, which is simple, quick and convenient to operate, and can achieve desired pitch attitude and heading changes in the autopilot state without taking hands off the stick, thereby reducing the pilot's operating burden under multi-tasking. The present invention does not add additional hardware resources, and can achieve rapid and accurate changes in the autopilot pitch / heading hold command by reusing the five-position longitudinal / lateral trim switch on the joystick handle. In addition, the command output rate of the present invention gradually changes from slow to fast, so that the aircraft has no control transients when the attitude / heading target value changes, and achieves a smooth transition of attitude and heading target value changes; at the same time, reasonable logic design avoids unexpected command changes caused by switch accidental contact or failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is a diagram of the five-position longitudinal and transverse trim switch;

[0016] Figure 2 It is a block diagram of pitch command change;

[0017] Figure 3 This is the block diagram of the heading angle command change. DETAILED DESCRIPTION

[0018] Example 1. A method for changing the automatic pilot hold command of a fly-by-wire aircraft, see Figure 1-Figure 3 , the pitch / heading control commands can be changed quickly and accurately through the five-position longitudinal and lateral trim switches on the joystick handle.

[0019] When the autopilot is not turned on, the longitudinal and lateral trim switches are used as basic trim functions. The longitudinal trim corresponds to the overload / pitch rate input, and the lateral trim corresponds to the roll rate command. When the autopilot is turned on and in the attitude and heading hold mode, the longitudinal and lateral trim inputs do not correspond to the overload or angular rate command inputs, but to the changes in the pitch and heading control target values, as follows:

[0020] When the longitudinal trim is performed forward, the pitch command gradually decreases at a certain rate of change based on the current pitch command; when the longitudinal trim is performed backward, the pitch command gradually increases at a certain rate of change based on the current pitch command; when the lateral trim is performed right, the heading command increases clockwise at a certain rate of change based on the current heading command; when the lateral trim is performed left, the heading command decreases counterclockwise at a certain rate of change based on the current heading command.

[0021] 1) Pitch hold command change

[0022] The pitch hold command change is to change the pitch angle of the autopilot pitch hold mode by manipulating the longitudinal trim switch on the joystick handle. For front trim, the desired pitch angle decreases, and for rear trim, the desired pitch angle increases. The specific logic is as follows:

[0023] a) If the single trim time (measured by the time the trim switch is continuously pressed) 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 a pitch angle, longitudinal front trim at a pitch angle), the aircraft will perform longitudinal leveling and enter the level flight state, at which time the pitch angle at the initial moment that satisfies 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, the switch operation will not be responded to;

[0024] b) If the single trim time is greater than T seconds, the command change is initiated, and the desired pitch angle command θ 期望 = "pitch angle θ at T seconds c "+" balance pitch angle θ p ” (integral of trim command after T seconds), the pitch angle command is expected to be updated in real time;

[0025] c) The pitch hold mode pitch angle limit threshold is ±θ 限制 , that is |θ 期望 |≤|θ 限制 |, so when |θ 期望 | Arrival θ 限制 When the trim switch is on, θ p will no longer change; and to prevent continuous input of the trim pitch angle when the switch is abnormally turned on, the maximum change of a single trim pitch angle command is ±θ 限制 .

[0026] The implementation diagram is as follows Figure 2 shown.

[0027] 2) Course command change logic

[0028] The heading hold command change is to change the heading angle of the autopilot heading hold mode by manipulating the lateral trim switch on the joystick handle. When trimming to the left, the desired heading angle decreases, and when trimming to the right, the desired heading angle increases. 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, lateral right trim when rolling left), the aircraft will level laterally and maintain the heading angle at the initial moment that meets the leveling end 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, the switch operation will not be responded to;

[0030] b) If the single trim time is greater than T seconds (regardless of whether the trim direction is the same as the aircraft roll attitude), the command change is initiated and the desired heading angle command r 期望 = "Heading angle r at T seconds c "+" Trim heading angle r p ” (integral of the trim command after T seconds), it is expected that the heading angle command will be updated in real time, so that the rate of change of the heading angle command will gradually increase as the trim time increases;

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

[0032] The implementation diagram is as follows Figure 3 shown.

Claims

1. A method for changing the automatic pilot holding instruction of a fly-by-wire aircraft, characterized in that: Including the pitch hold command change, after the autopilot is activated, the pitch angle change of the autopilot pitch hold mode is achieved by operating the longitudinal trim switch on the joystick handle; in the pitch hold command change, the expected pitch angle decreases during the forward trim and increases during the rear trim.

2. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 1, characterized in that: 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 longitudinally and enter the level flight state, at which time the pitch angle at the initial moment that meets the leveling end condition is maintained.

3. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 2, characterized in that: 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.

4. The method for changing the automatic hold instruction of a fly-by-wire aircraft according to claim 2, characterized in that: If the single trim time is greater than T seconds, the command change is initiated; the desired pitch angle command θ 期望 =θ c +θ p , where θ c is the pitch angle at T seconds, θ p is the trim pitch angle; θ p Calculated by integrating the trim commands after T seconds.

5. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 4, characterized in that: Assume that the pitch angle limit threshold of the pitch hold mode is ±θ 限制 , when |θ 期望 | Arrival θ 限制 When the trim switch is on, θ p No longer changes; at the same time, the maximum change of a single trim pitch angle command is ±θ 限制 .

6. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 1, characterized in that: It also includes heading hold command changes, which is achieved by operating the lateral trim switch on the joystick handle to change the heading angle maintained in the autopilot heading hold mode after activating the autopilot; when trimming to the left, the desired heading angle is reduced, and when trimming to the right, the desired heading angle is increased.

7. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 6, 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's roll attitude, the aircraft will level laterally and maintain the heading angle at the initial moment that meets the leveling end condition.

8. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 7, characterized in that: If the single trim time is less than or equal to T seconds, and the trim direction is the same as the flying roll attitude, there will be no response to the switch operation.

9. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 7, characterized in that: If the single trim time is greater than T seconds, the command change is started, and the expected heading angle command r 期望 =r c +r p , where r c is the heading angle at T seconds, r p is the trim heading angle; r p Calculated by integrating the trim commands after T seconds.

10. The method for changing the automatic flight hold command of a fly-by-wire aircraft according to claim 9, characterized in that: The heading angle maintained in heading hold mode is 0 to 359°; at the same time, the maximum change of a single trim lateral angle command is ±180°.

Images