A method and system for thrust control in a flight altitude layer change mode

Abstract

The application relates to a thrust control system under a FLCH mode, comprising: an upper branch, comprising: a height difference calculation module configured to calculate a height difference between a target height and a current height of an aircraft; a latch module configured to latch a value of the height difference according to a manual operation reaction time delay and an industry requirement; a vertical speed calculator configured to calculate a corresponding expected vertical speed according to the latched height difference output by the latch module; and a thrust calculator configured to calculate a corresponding thrust according to the expected vertical speed; a lower branch, comprising: a selector configured to select an integral rate according to an integral rate judgment condition; an integrator configured to integrate by time according to the selected integral rate to output a compensation thrust; and an adder configured to add the thrust from the upper branch and the compensation thrust from the lower branch to output a thrust command.

Description

Technical Field

[0001] This application relates to the field of design of automatic flight control systems for civil aircraft, and more specifically, to a thrust control scheme under the flight level change mode (FLCH mode) of an automatic flight control system for civil aircraft. Background Technology

[0002] FLCH stands for "Flight Level Change," and it is one of the most commonly used modes in the automatic flight control systems of civil aircraft. The control characteristics of FLCH mode are: when this mode is activated, the autothrottle and vertical axis control work together to control the aircraft to rapidly climb or descend to the designated flight level.

[0003] Typically, FLCH mode is activated via the FLCH button on the flight mode control panel. Because this mode is easy to operate and allows for rapid climb / descent control while maintaining target speed to prevent the aircraft from entering dangerous speed zones, it is one of the most commonly used climb / descent modes for civilian aircraft pilots.

[0004] The FLCH mode is characterized by its automatic throttle control maintaining a constant thrust to provide the energy needed for climb / descent. Vertical axis autopilot controls flight attitude via elevators, achieving target speed control.

[0005] Based on the control characteristics of FLCH mode, existing FLCH mode control methods have the following core problem: how to control engine thrust to provide enough energy to meet the necessary climb rate and acceleration / deceleration requirements for flight, without resulting in excess engine energy. Excess energy refers to the energy provided by the engine exceeding the energy required for flight climb / deceleration and acceleration / deceleration. If the excess energy is too large, it will cause excessive aircraft maneuverability, excessive load, affecting comfort, and damaging the engine.

[0006] For thrust control in FLCH mode, common control methods currently include:

[0007] (1) Without distinguishing between climb / descent altitude differences, the throttle is moved to the TOGA position during climb to provide maximum continuous thrust; during descent, it is moved to the IDLE position to provide idle thrust. This control method results in a large amount of engine energy surplus during climb / descent. Especially in climb / descent scenarios with small altitude differences, using this control method causes the aircraft to maneuver rapidly, quickly acquire the target altitude, and maintain it. The load is too high throughout the climb, affecting passenger comfort.

[0008] (2) In the FLCH climbing / descending scenario with a small height difference, the vertical axis control is fixed at a vertical speed, and the throttle only controls the speed. However, if the target speed is reduced during the climb, this mechanism may have the disadvantage of controlling the speed by reducing the throttle.

[0009] For example, reference D1 (CN 113778116 B) discloses a flight altitude change control device and method for a civil airliner, which proposes an engine throttle controller based on energy management. The difference between desired and undesired energy is used for PID control to obtain the throttle thrust. However, this control method cannot guarantee the aircraft's vertical speed, especially in FLCH mode deceleration climb / acceleration descent scenarios, where the vertical speed may be too low, resulting in excessively long time to reach the target altitude. Furthermore, the control method requires precise aircraft mass calculations; otherwise, the control effect is directly affected. However, obtaining precise mass values ​​is difficult.

[0010] Reference D2 (CN105912006 B) discloses a go-around control method for an aircraft, which proposes a thrust control method during the go-around process, including three steps: S1. Using the flight control system, the go-around thrust, the vertical velocity of the go-around target, and the airspeed of the go-around target are obtained in the current state of the aircraft; S2. Pressing the go-around button, the autothrottle pushes the throttle stick to the go-around thrust position of the aircraft, the autothrottle maintains the target thrust, the aircraft pitches up and increases the current vertical velocity to the target vertical velocity; S3. After the vertical velocity of the aircraft reaches the target vertical velocity, the aircraft climbs towards the target airspeed at the current airspeed.

[0011] Reference D3 (US5386954 A) discloses the flight process of an aircraft maintaining speed on an elevator, and proposes a control method in FLCH mode, which consists of two stages. Taking climb as an example, in the first stage, the elevator generates a pitch command, and simultaneously calculates the throttle command using the expected speed and the feedback real-time speed to prevent the aircraft from losing speed. In the second stage, the throttle is set to the maximum thrust position and maintained at a fixed thrust, with the aircraft controlling its speed using the elevator.

[0012] Reference D4 (US5031102 A) discloses a method and apparatus for controlling aircraft pitch and thrust axis, which proposes an automatic or semi-automatic vertical trajectory control system for aircraft, wherein during climb in FLCH mode, the thrust is controlled to the upper thrust limit; during descent in FLCH mode, the thrust is controlled to the IDLE thrust.

[0013] However, in the schemes of references D3 and D4, the upper thrust limit is still used for climbing and the IDLE thrust is still used for descent. Therefore, the above-mentioned first technical problem still exists in the schemes.

[0014] Therefore, there is a need for a thrust control scheme that can both maintain the desired vertical speed during climb / descent and ensure the kinetic energy required for the aircraft to perform acceleration and deceleration operations. Summary of the Invention

[0015] In this application, the core of the thrust control scheme in FLCH mode is to control the thrust based on the desired vertical speed and the kinetic energy required for the aircraft to accelerate and decelerate during the climb. That is, the calculated thrust should be able to maintain the desired vertical speed during the climb / descent and also ensure the kinetic energy required for the aircraft to perform acceleration and deceleration operations.

[0016] According to a first aspect of this application, a thrust control system in FLCH mode is provided, comprising:

[0017] The upper branch road includes:

[0018] The altitude difference calculation module is configured to calculate the altitude difference between the target altitude and the aircraft's current altitude;

[0019] The latch module is configured to latch the height difference based on the response time delay of manual operation and industry requirements.

[0020] A vertical speed calculator is configured to calculate the corresponding desired vertical speed based on the latch height difference output by the latch module.

[0021] A thrust calculator is configured to calculate the corresponding thrust based on the desired vertical velocity;

[0022] The lower branch road includes:

[0023] The selector is configured to select the integral rate based on the integral rate judgment condition.

[0024] An integrator, configured to integrate over time according to a selected integration rate to output compensated thrust; and

[0025] An adder is configured to add the thrust from the upper branch to the compensated thrust from the lower branch to output a thrust command.

[0026] According to a second aspect of this application, a thrust control method in FLCH mode is provided, comprising:

[0027] Thrust calculation sub-process:

[0028] Calculate the altitude difference between the target altitude and the aircraft's current altitude;

[0029] Based on the difference between the response time delay of manual operation and the latching height required by the industry;

[0030] Calculate the corresponding desired vertical velocity based on the height difference of the latch;

[0031] Calculate the corresponding thrust based on the desired vertical velocity;

[0032] Compensation thrust sub-process:

[0033] Select the integral rate based on the integral rate judgment condition;

[0034] Integrate over time according to the selected integration rate to output compensated thrust; and

[0035] The thrust from the thrust calculation subprocess is added to the compensated thrust from the compensated thrust subprocess to output a thrust command.

[0036] This overview is provided to introduce, in a simplified form, some of the concepts further described in the detailed description below. This overview is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Attached Figure Description

[0037] To describe how the above and other advantages and features of the invention are obtained, a more detailed description of the invention, which has been briefly described above, will be presented with reference to specific embodiments of the invention shown in the accompanying drawings. It will be understood that these drawings depict only exemplary embodiments of the invention and are therefore not intended to limit its scope. The invention will be described and explained using the drawings and with the aid of additional features and details, in which:

[0038] Figure 1 An example logic diagram of a thrust control system in Flight Altitude Layer Change (FLCH) mode according to an embodiment of this application is shown.

[0039] Figure 2 An example structural diagram of a latching module in a thrust control system according to an embodiment of this application is shown.

[0040] Figure 3 An example flowchart of a thrust control method in Flight Altitude Layer Change (FLCH) mode according to an embodiment of this application is shown. Detailed Implementation

[0041] In this application, the core of the thrust control scheme in FLCH mode is to control the thrust based on the desired vertical speed and the kinetic energy required for the aircraft to accelerate and decelerate during the climb. That is, the calculated thrust should be able to maintain the desired vertical speed during the climb / descent and also ensure the kinetic energy required for the aircraft to perform acceleration and deceleration operations.

[0042] The following is for reference. Figure 1 This document describes an example logic diagram of a thrust control system in Flight Altitude Layer Change (FLCH) mode according to an embodiment of this application.

[0043] As shown in the figure, the thrust control system is implemented through a combination of upper and lower branches.

[0044] The upper branch is the thrust calculation branch, which enables thrust control based on the desired vertical velocity.

[0045] In summary, the thrust calculation branch includes the following operations:

[0046] After activating FLCH mode, the altitude difference between the aircraft's current altitude and the target altitude is first calculated. Then, the desired vertical velocity is calculated by interpolation based on the altitude difference. Finally, the thrust required to achieve the desired vertical velocity is calculated using the formula for steady climb of the aircraft.

[0047] In general, the design standards for civil aircraft stipulate requirements such as reaching the target altitude within a specified time T seconds in FLCH mode. Therefore, the principle for selecting the desired vertical speed is: if the aircraft's capabilities are not limited, it must reach the predetermined altitude within the specified time T; if the aircraft's capabilities are limited, it should climb / descend according to its maximum climb / descend performance.

[0048] Therefore, the greater the elevation difference during ascent / descent, the greater the desired vertical speed. When ascending / descending with a small elevation difference, the interpolated vertical speed will not be too large to avoid excessive load due to rapid maneuvering; when ascending / descending with a large elevation difference, the interpolated vertical speed will be slightly larger to meet the requirement of reaching the designated target layer within a specified time.

[0049] To achieve the above operations, the upper branch correspondingly provides an altitude difference calculation module, a latching module, a vertical velocity calculator, and a thrust calculator coupled via a communication medium. The communication medium includes wired media such as A664 or A429 buses, as well as wireless networks.

[0050] First, the altitude difference calculation module is configured to calculate the altitude difference (ALT) between the target altitude and the aircraft's current altitude. error The aircraft's current real-time altitude can be obtained from the aircraft's atmospheric system, while the target altitude is obtained from the flight mode control panel, for example, by manual input from the pilot.

[0051] The latching module is configured to latch the height difference based on the manual operation response time delay and industry requirements.

[0052] Specifically, the latch module employs two latches. An example logic structure of the latch module is as follows: Figure 2 As shown.

[0053] The function of the first latch is to allow the pilot confirmation time for setting the altitude. That is, only after the pilot has selected the target altitude and maintained it for a certain period will the first latch latch the target altitude and output the altitude difference (ALT). error_unchanged For example, if the aircraft is at an altitude of 500 feet and the target altitude is 2000 feet, ideally the pilot would directly adjust to 2000 feet. However, in reality, the pilot might hesitate for 0.1 seconds when adjusting to 1000 feet, then hesitate again at 1800 feet, before adjusting to 2000 feet. Without a first latch, the system might calculate the desired vertical velocity and thrust three times, treating 1000 feet, 1800 feet, and 2000 feet as the target altitude respectively. The first latch allows for a reaction confirmation period, such as Y seconds, after the pilot adjusts the target altitude before starting the calculation, thus avoiding the problems caused by the delay in manual operation reaction time. It should be understood that if the pilot is familiar with the system and skilled in operation, the confirmation time in the first latch can be set to a smaller value for such an experienced pilot. Conversely, if the pilot is an inexperienced novice with a slower reaction speed, this time can be set to a larger value.

[0054] The function of the second latch is to specify when the latch needs to be restarted during the climb / descent in FLCH mode to calculate the desired vertical velocity and thrust and output the latched height difference when the target altitude is modified.

[0055] Specifically, if the original target altitude is greater than the aircraft's actual altitude, during a climb in FLCH mode, if the pilot continues to increase the target altitude, the second latch will be reactivated to recalculate the desired vertical velocity and increase thrust. However, during a climb in FLCH mode, if the pilot continues to decrease the target altitude (but the newly set target altitude is still greater than the aircraft's actual altitude), the second latch will not be activated, and the thrust will remain unchanged. This satisfies the industry requirement that thrust cannot decrease during a climb in FLCH mode.

[0056] Similarly, if the original target altitude is lower than the aircraft's actual altitude, during FLCH mode descent, if the pilot continues to lower the target altitude, the second latch will be restarted to recalculate the desired vertical velocity and reduce thrust. However, during FLCH mode descent, if the pilot raises the target altitude (but the newly set target altitude is still lower than the aircraft's actual altitude), the second latch will not be activated, and the thrust will remain unchanged and will not increase. This satisfies the industry requirement that thrust cannot increase during FLCH mode descent.

[0057] From a logical judgment perspective, the second latch executes the following latch judgment logic:

[0058] Among them, the output ALT of the first latch error_unchanged As an input to the second latch, the second latch initiates latching and outputs the latched ALT value if any of the following conditions are met. error_latch :

[0059] (a) If the height difference between the target height and the current height is greater than 0, and the height difference output by the first latch increases, that is, when ALT... error Greater than 0, and ALT error_unchanged If the target altitude is increased, the second latch will be activated. The scenario described is: during a climb in FLCH mode, if the target altitude is greater than the aircraft's actual altitude, and the pilot continues to increase the target altitude, the latch needs to be restarted to calculate the altitude difference and increase thrust.

[0060] (b) If the height difference between the target height and the current height is less than 0, and the height difference output by the first latch decreases, that is, when ALT... error Less than 0, and ALT error_unchanged If the target altitude is reduced, the second latch is activated. The scenario described is: during descent in FLCH mode, the target altitude is lower than the aircraft's actual altitude, and the pilot continues to lower the target altitude. In this case, the latch needs to be restarted to calculate the target altitude difference and reduce thrust.

[0061] (c) When initially activating FLCH mode, it is necessary to start latching to calculate the height target difference.

[0062] In other cases, the second latch does not activate latching, meaning there is no need to change the vertical velocity and thrust.

[0063] Without adding a second latch, if the pilot lowers the target altitude during FLCH climb or raises the target altitude during FLCH descent, the aircraft may reduce throttle to decrease thrust, violating industry requirements and causing unnecessary interference to the pilot.

[0064] It should be understood that the terms "first" and "second" mentioned above are merely for the purpose of distinguishing between the two latches, and are not specific restrictions.

[0065] The vertical speed calculator is configured to calculate the corresponding desired vertical speed based on the latched height difference output by the latch module.

[0066] When calculating the desired vertical speed, it is necessary to consider how to meet industry standards for rapid access to the target altitude level in FLCH mode, while also taking into account passenger comfort and energy-saving design features.

[0067] Specifically, firstly, civil aircraft design standards generally stipulate requirements such as reaching the target altitude within a specified time T seconds in FLCH mode. Therefore, the calculated desired vertical speed must meet this requirement. This determines the lower limit of the desired vertical speed. As long as the aircraft is climbing, it should exceed this rate of climb. Theoretically, desired vertical speeds exceeding this lower limit can meet the above requirements, but while higher vertical speeds allow for a faster arrival at the target altitude, passenger comfort may be compromised, and thrust (energy) waste may be more significant. In addition, industry requirements also include a default minimum vertical speed. Taking FLCH climb as an example: during FLCH climb, the automatic flight system cannot instruct the aircraft to descend. Therefore, a small vertical speed target, such as 250 ft / min, is set as the lower limit of the desired vertical speed to ensure that the aircraft does not descend during FLCH climb.

[0068] Therefore, the vertical velocity calculator can be implemented in several modes:

[0069] 1) The desired vertical velocity is calculated in real time based on the latched altitude difference and the specified time T for reaching the target altitude level. For example, if FLCH mode requires reaching an altitude of 8000ft within 1 minute, and the aircraft's current altitude is 5000ft, then the desired vertical velocity VS0 is calculated in real time. exp =(8000-5000) / 1=3000ft / min.

[0070] Of course, exceeding this vertical speed also meets the requirements, but passenger comfort and energy efficiency must also be taken into account. Higher vertical speeds can cause passenger discomfort. For example, in FLCH mode climb / descent scenarios with small altitude differences, excessive vertical speed will cause the aircraft to immediately acquire the target altitude, resulting in significant G-forces, which is detrimental to both economy and passenger comfort.

[0071] In addition, as mentioned above, the industry standard vertical speed should be no less than 250 ft / min. If the calculated vertical speed is less than 250 ft / min, then 250 ft / min can be used directly as the vertical speed.

[0072] However, this real-time calculation actually consumes a significant amount of system resources and has a relatively long response time. Therefore, the industry typically uses the following interpolation table method for faster calculation.

[0073] 2) The desired vertical speed is calculated using an interpolation table. Specifically, the desired vertical speed is obtained by interpolating the height difference output by the latching module based on the interpolation table. Different ascent / descent height differences will result in different desired vertical speeds.

[0074] Specifically, given that numerous pilots and aircraft worldwide perform climb / descent maneuvers at varying altitudes daily, a wealth of industry experience exists regarding optimal vertical speeds for different altitude differences that simultaneously meet industry standards for rapid arrival at target altitudes while maintaining passenger comfort and fuel efficiency. Therefore, an interpolation table can be designed based on this accumulated industry experience. This interpolation table includes multiple records. Each record includes a specific locked altitude difference and an empirically set, preferred desired vertical speed for that altitude difference. An example of such an interpolation table is shown below:

[0075] Breakpoints ALT_error_latch(ft) <![CDATA[VS exp (ft / min)]]> (1) -2000 -7700 (2) -1000 -1400 (3) -0.1 -250 (4) 0 0 (5) 0.1 250 (6) 1000 1400 (7) 2000 7700

[0076] Based on these specific records in the interpolation table, for latched height differences not recorded in the interpolation table, the corresponding expected vertical velocity can be derived through interpolation, i.e., the formula:

[0077] VS exp =f(ALT) error_latch (1)

[0078] Among them VS exp denoted by , where f represents the desired vertical velocity, and f represents interpolation based on an interpolation table.

[0079] The thrust calculator is configured to calculate the corresponding thrust based on the desired vertical velocity. At this thrust, the aircraft can maintain a steady-state desired vertical velocity to reach the target altitude.

[0080] Specifically, the required thrust can be calculated based on the desired vertical velocity using the formula for steady climb of an aircraft. An example formula for steady climb of an aircraft is shown below:

[0081] γ exp =VS exp / GS (2)

[0082] F=D+Wsinγ exp (3)

[0083] Where, γ exp GS represents the desired flight path angle; ground speed is derived from the aircraft's inertial navigation system; thrust is F; drag is D, which can be calculated from the aircraft's aerodynamic drag coefficient and flight speed; and weight is W, derived from the aircraft's flight control system.

[0084] From the formula above, we can understand that, firstly, based on the desired vertical velocity VS... exp The ratio of the ground speed GS to the desired flight path angle can be calculated.

[0085] The thrust is then calculated by adding the product of the aircraft's drag and gravity to the sine of the desired flight path angle, and output to an input of a subsequent adder.

[0086] Using the aforementioned upper branch, the desired vertical velocity and corresponding thrust can be adaptively varied. That is, when the height difference changes, the system will automatically recalculate the corresponding desired vertical velocity and thrust as needed.

[0087] However, the thrust calculated using the aforementioned upper branch cannot meet the actual requirements. The reason is:

[0088] 1) In the above thrust calculation process, parameters such as flight drag and aircraft gravity are required, but these parameters are often not accurately obtained;

[0089] 2) The aircraft’s (horizontal) speed may change during its flight, such as acceleration or deceleration, and these changes will also affect the thrust.

[0090] Therefore, in order to make the calculated thrust more accurate, a thrust compensation mechanism was designed in the lower branch.

[0091] In other words, the upper branch alone cannot accurately control the aircraft to achieve the desired vertical speed. Therefore, thrust compensation is also required through integral control of the lower branch based on vertical speed feedback. Thus, the command output by the lower branch supplements the thrust output by the upper branch.

[0092] Specifically, such as Figure 1 As shown, the lower branch includes a selector and an integrator, and its working principle is as follows:

[0093] Taking FLCH mode climb as an example, the integrator will start when all of the following conditions are met:

[0094] ①Activate FLCH mode;

[0095] ② Climbing phase;

[0096] Condition 1 indicates that FLCH mode is activated; Condition 2 indicates that the aircraft is in the climb phase.

[0097] The integral rate is set using the following integral rate determination conditions:

[0098] ① If the actual vertical velocity is not less than the desired vertical velocity, then the integral rate is 0. This situation indicates that if the actual vertical velocity is greater than or equal to the desired vertical velocity, the current thrust is sufficient to maintain the desired vertical velocity, and no further thrust is needed.

[0099] ② The actual vertical velocity is less than the desired vertical velocity, and the actual flight speed is less than the target flight speed, with an integral rate of K1. This situation indicates that since the actual vertical velocity is less than the desired vertical velocity and the actual flight speed is also less than the target flight speed, a relatively rapid increase in thrust is required. The increased thrust is used to increase the vertical velocity and to provide kinetic energy to the aircraft. Therefore, the value of the provided integral rate is relatively large.

[0100] ③ The actual vertical velocity is less than the desired vertical velocity, but the actual flight speed is not less than the target flight speed, and the integral rate is K2. This situation indicates that: the actual vertical velocity is less than the desired vertical velocity, so thrust still needs to be increased to increase the vertical velocity. However, since the actual flight speed is greater than the target flight speed, this excess kinetic energy can be converted into vertical velocity, so an excessively large integral rate is not required.

[0101] Therefore, the relationship of the integral rates should satisfy: K1>K2>0.

[0102] It should be understood that the purpose of the above operation is: if the actual vertical speed of the aircraft does not reach the desired vertical speed under the thrust of the upper branch, the thrust can be slowly compensated by the lower branch to achieve the desired vertical speed. Therefore, the values ​​of K1 and K2 should not be too large. The specific range of these values ​​is generally selected based on the results of simulation tests.

[0103] Specifically, if the value of K is too large in the simulation tests for the three scenarios mentioned above, the compensated vertical speed of the current aircraft may be too large, deviating far from the desired vertical speed, so the value of K is adjusted downwards. Conversely, if the value of K is too small, the compensated vertical speed of the current aircraft may be too small, still deviating far from the desired vertical speed, so the value of K is adjusted upwards. This process is repeated until the value of K causes the compensated vertical speed to fall within an acceptable range of the desired vertical speed; this value is then determined as the final value of K. Generally, the values ​​of K1 and K2 are preferably around 0-0.5.

[0104] After the selector selects the corresponding value (0, K1, or K2) based on the above integration rate judgment condition and outputs it to the integrator, the integrator integrates over time according to the selected integration rate to output the compensated thrust as another input to the adder. It can be understood that when the integration rate is 0, the integrator does not actually integrate, therefore, the output compensated thrust is also actually 0, that is, no thrust compensation is required.

[0105] Finally, the adder is configured to add the calculated thrust from the upper branch to the compensated thrust from the lower branch to output the final thrust command.

[0106] Therefore, based on the final output thrust command, the throttle lever is not necessarily limited to the TOGA or IDLE position.

[0107] When climbing / descending in FLCH mode with small elevation differences, the throttle lever is generally in the middle position, providing the necessary thrust for climbing / descending. This not only provides passengers with better comfort but also saves energy. Therefore, in this scenario, the solution proposed in this application is superior to the conventional FLCH mode thrust control method.

[0108] If the height difference is large, the throttle lever may reach the TOGA / IDLE position under thrust control. In this scenario, the throttle lever remains at the TOGA / IDLE position, and the thrust control method of this application is the same as the conventional FLCH mode thrust control method.

[0109] Having described the example logic structure diagram of the thrust control system, the following section refers to the example structure of the thrust control system. Figure 3 An example flowchart is provided to describe a thrust control method in Flight Altitude Layer Change (FLCH) mode according to an embodiment of this application.

[0110] As shown in the figure, the thrust control method begins execution when the pilot activates FLCH mode. As previously mentioned, the scheme can be divided into two branches: the left branch of the method flow executes the processing in the upper branch of the thrust control system, namely the thrust calculation sub-flow; while the right branch of the method flow executes the processing in the lower branch of the thrust control system, namely the thrust compensation sub-flow.

[0111] First, in the thrust calculation sub-process:

[0112] In step 302, the altitude difference calculation module calculates the altitude difference between the target altitude and the aircraft's current altitude.

[0113] Subsequently, in step 304, the latching module calculates the difference between the manual operation response time delay and the industry-required latching height.

[0114] As previously mentioned, the latching module may include two latches.

[0115] The function of the first latch is to allow the pilot confirmation time for setting the altitude. That is, only after the pilot has selected the target altitude and maintained it for a certain period will the first latch latch the target altitude and output the altitude difference (ALT). error_unchanged Give it to the second latch.

[0116] The function of the second latch is to specify when to restart the latch to calculate the desired vertical velocity and thrust when the target altitude is modified during climb / descent in FLCH mode, and to output the latched altitude difference ALT.error_latch To meet industry needs.

[0117] Subsequently, in step 306, the vertical speed calculator calculates the corresponding desired vertical speed based on the latch height difference output by the latch module.

[0118] As mentioned earlier, the desired vertical speed in FLCH mode can meet industry standards for rapid access to the target altitude level while also taking into account passenger comfort and energy-saving design features.

[0119] The calculation can be performed in real time based on the latched height difference and the specified time T for reaching the target height level.

[0120] Using an interpolation table (see Table 1, Formula 1 and related content) to calculate the desired vertical velocity is more convenient and faster.

[0121] Next, in step 308, the thrust calculator calculates the corresponding thrust based on the desired vertical velocity. The specific calculation process can be found in formulas 2 and 3 and their related content.

[0122] Simultaneously, another sub-process for compensating thrust can also be executed concurrently, mainly including: selecting the integration rate based on the integration rate determination condition; and integrating over time according to the selected integration rate to output the compensating thrust. Specifically:

[0123] In step 303, firstly, it is determined whether the current actual vertical speed is less than the expected vertical speed.

[0124] If not, the process proceeds to step 305, where the selector selects an integration rate of 0, and the process then proceeds to step 313.

[0125] If so, the process proceeds to step 307, where it is determined again whether the actual flight speed is less than the target flight speed.

[0126] If so, the process proceeds to step 309, where the selector selects the integration rate as K1, and the process then proceeds to step 313.

[0127] If not, the process proceeds to step 311, where the selector selects the integration rate as K2, and the process then proceeds to step 313.

[0128] In step 313, the integrator integrates over time according to the integration rate received from the selector to output compensated thrust.

[0129] Finally, in step 320, the final thrust command is generated by summing the thrust output from step 308 and the thrust output from step 313.

[0130] Thus, based on the thrust command, the throttle lever can be positioned appropriately to generate the corresponding thrust.

[0131] Compared to the conventional FLCH mode technology, if the height difference is large, the throttle lever under thrust control in this solution may still reach the TOGA / IDLE position. In this scenario, the throttle lever will remain at the TOGA / IDLE position, which is the same as the thrust control method in the conventional FLCH mode.

[0132] However, when climbing / descending at small elevation differences, the throttle lever under thrust control in this solution can be positioned in the middle to provide the necessary thrust for climbing / descending. This not only provides passengers with better comfort but also saves energy. Therefore, in this scenario, the solution proposed in this application is superior to the conventional FLCH mode thrust control method.

[0133] While different embodiments have been described above, it should be understood that they are merely examples and not limitations. Those skilled in the art will appreciate that various modifications in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A thrust control system in FLCH mode, comprising: The upper branch road includes: The altitude difference calculation module is configured to calculate the altitude difference between the target altitude and the aircraft's current altitude; The latch module is configured to latch the height difference based on the response time delay of manual operation and industry requirements. A vertical speed calculator is configured to calculate the corresponding desired vertical speed based on the latch height difference output by the latch module. A thrust calculator is configured to calculate the corresponding thrust based on the desired vertical velocity; The lower branch road includes: The selector is configured to select the integral rate based on the integral rate judgment condition. An integrator, configured to integrate over time according to a selected integration rate to output compensated thrust; and An adder is configured to add the thrust from the upper branch to the compensated thrust from the lower branch and output a thrust command. The latching module includes: A first latch is configured to latch the target height and output the height difference to the input of a second latch after detecting that the selected target height has been maintained for a period of time. The second latch is configured to initiate latching based on latching decision logic to output the height difference of the latch.

2. The thrust control system as described in claim 1, characterized in that, The latching judgment logic includes: (a) If the height difference between the target height and the current height is greater than 0, and the height difference output by the first latch increases, then the second latch is activated; (b) If the height difference between the target height and the current height is less than 0, and the height difference output by the first latch decreases, then the second latch is activated; (c) When the FLCH mode is initially activated, the second latch is started.

3. The thrust control system as described in claim 1, characterized in that, The vertical velocity calculator uses an interpolation table to calculate the desired vertical velocity according to the following formula: （1） in, VS exp This represents the desired vertical velocity. f Indicates that interpolation is performed based on the interpolation table, ALT error_latch This indicates the height difference of the latch output by the latch module.

4. The thrust control system as described in claim 1, characterized in that, The thrust calculator calculates the thrust according to the following formula for steady climb of an aircraft: （2） （3） in, γ exp Indicates the desired flight path angle; GS Indicates ground speed; F For thrust; D For flight drag; W For the aircraft's gravity.

5. The thrust control system as described in claim 1, characterized in that, The selector selects the integral rate based on the following integral rate judgment condition: Climbing phase in the FLCH mode: 1) If the actual vertical velocity is not less than the expected vertical velocity, then the integral rate is 0; 2) If the actual vertical speed is less than the expected vertical speed and the actual flight speed is less than the target flight speed, then the integral rate is K1; 3) If the actual vertical speed is less than the expected vertical speed, and the actual flight speed is not less than the target flight speed, then the integral rate is K2; The relationship between the integral rates satisfies: K1>K2>0.

6. A thrust control method in FLCH mode, comprising: Thrust calculation sub-process: Calculate the altitude difference between the target altitude and the current altitude of the aircraft; Based on the difference between the response time delay of manual operation and the latching height required by the industry; Calculate the corresponding desired vertical velocity based on the height difference of the latch; Calculate the corresponding thrust based on the desired vertical velocity; Compensation thrust sub-process: Select the integral rate based on the integral rate judgment condition; Integrate over time according to the selected integration rate to output compensated thrust; and The thrust from the thrust calculation subprocess is added to the compensated thrust from the compensated thrust subprocess to output a thrust command. The step of determining the difference between the manual operation response time delay and the industry-required latch height includes: After detecting that the selected target height has been maintained for a period of time, the first latch latches the target height and outputs the height difference to the input of the second latch; The second latch starts latching according to the latching judgment logic to output the height difference of the latch.

7. The thrust control method as described in claim 6, characterized in that, in, The latching judgment logic includes: (a) If the height difference between the target height and the current height is greater than 0, and the height difference output by the first latch increases, then the second latch is activated; (b) If the height difference between the target height and the current height is less than 0, and the height difference output by the first latch decreases, then the second latch is activated; (c) When the FLCH mode is initially activated, the second latch is started.

8. The thrust control method as described in claim 6, characterized in that, The step of calculating the corresponding desired vertical velocity based on the latched height difference includes: The desired vertical velocity is calculated using an interpolation table according to the following formula: （1） in, VS exp This represents the desired vertical velocity. f Indicates that interpolation is performed based on the interpolation table, ALT error_latch This indicates the height difference of the latch; and The step of calculating the corresponding thrust based on the desired vertical velocity includes: calculating the thrust according to the following formula for steady climb of an aircraft: （2） （3） in, γ exp Indicates the desired flight path angle; GS Indicates ground speed; F For thrust; D For flight drag; W For the aircraft's gravity.

9. The thrust control method as described in claim 6, characterized in that, Select the integral rate based on the following integral rate criteria: Climbing phase in the FLCH mode: Determine whether the current actual vertical velocity is less than the expected vertical velocity: If not, the integration rate is 0; If so, then determine whether the actual flight speed is less than the target flight speed: If so, then select the integration rate as K1; If not, then select the integration rate as K2; The relationship between the integral rates satisfies: K1>K2>0.

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