An automatic go-around control device, control method and aircraft based on an overload control law

Abstract

The disclosure provides an automatic go-around control device based on overload control law, a control method and an airplane. The device comprises a reference pitch angle generating unit, a reference speed generating unit, a pitch angle control loop overload command generating unit, a speed control loop overload command generating unit and an overload command selection unit. After the airplane enters the automatic go-around mode, the device generates a reference pitch angle and a reference speed based on state information, and generates a first overload command and a second overload command respectively. The overload command selection unit preferentially outputs the first overload command within a first preset time at the beginning of go-around to ensure the rapid establishment of the go-around attitude, and then switches to the second overload command when the switching condition is met to realize accurate speed tracking. The device realizes stage-by-stage and adaptive overload command switching, which not only ensures the safe take-off attitude at the beginning of go-around, but also optimizes the subsequent speed control accuracy, effectively reduces the pilot's operation load, and improves the stability and reliability of the go-around process.

Description

Technical Field

[0001] This disclosure belongs to the field of aircraft automatic flight control technology, specifically relating to an automatic go-around control device, control method, and aircraft based on an overload control law. Background Technology

[0002] Automatic flight control systems are widely used in modern aircraft, reducing the pilot's workload and minimizing human error during flight. Automatic go-around, a crucial function of automatic flight control, is typically triggered when an aircraft encounters an anomaly during approach or landing. It is used to control the aircraft to establish a go-around attitude and re-enter a safe climb state.

[0003] In existing automatic go-around control schemes, one type typically uses pitch angle or vertical velocity targets as the controlled object, and then converts this target into control commands suitable for the flight control system through an additional control law. For aircraft using overload control laws, this type of scheme often requires an additional target conversion stage, which can easily lead to a complex control link, reduced system stability margin, and adverse effects on control performance.

[0004] Furthermore, existing technologies present the following problems: During the initial go-around phase, if the aircraft is in a low-energy state while the control system continues to output significant pitch control demands, the aircraft speed may decrease further, increasing the risk of underspeed. Under go-around thrust, the lack of effective speed constraints or boundary protection may cause the aircraft speed to increase rapidly during the go-around process, even approaching overspeed limits. Simultaneously, direct switching between different control phases may cause abrupt changes in overload commands or pitch attitude, affecting the stability and passenger comfort during the go-around process.

[0005] Therefore, an automatic go-around control scheme that is more suitable for aircraft with overload control laws is needed to take into account initial pitch establishment, speed maintenance, smooth switching, and flight boundary constraints during the go-around process. Summary of the Invention

[0006] To address the aforementioned issues, the purpose of this disclosure is to provide an automatic go-around control device, control method, and aircraft based on an overload control law, so as to realize the phased output and switching control of the first overload command and the second overload command during the automatic go-around process, thereby facilitating both attitude establishment in the initial stage of go-around and speed maintenance thereafter.

[0007] This disclosure provides an automatic go-around control device based on an overload control law, comprising: a reference pitch angle generation unit, used to generate a reference pitch angle for automatic go-around based on the aircraft's state information after the aircraft enters the automatic go-around mode; a reference speed generation unit, used to generate a reference speed for automatic go-around based on the aircraft's speed information after the aircraft enters the automatic go-around mode; a pitch angle control loop overload command generation unit, connected to the reference pitch angle generation unit, used to generate a first overload command based on the reference pitch angle and the aircraft's pitch information; and a speed control loop overload command generation unit, connected to the reference speed generation unit, used to generate a first overload command based on the reference speed and the aircraft's speed. The system generates a second overload command based on the altitude information. An overload command selection unit, whose inputs are connected to both the pitch angle control loop overload command generation unit and the speed control loop overload command generation unit, outputs a go-around overload control command to the main flight control law of the flight control computer. The overload command selection unit is configured to: output the first overload command as the go-around overload control command to the main flight control law within a first preset time after the aircraft enters automatic go-around mode; and after the first preset time, when a preset switching condition is met, switch the first overload command to the second overload command and output it to the main flight control law to control the aircraft to complete the automatic go-around.

[0008] Alternatively, the reference pitch angle generation unit may be further configured to: use a fixed value as the reference pitch angle when the aircraft is in a twin-engine go-around state; and determine the reference pitch angle based on the aircraft's flap angle and weight when the aircraft is in a single-engine go-around state.

[0009] Alternatively, the reference speed generation unit may be further configured to: use the larger of the speed at which the aircraft enters the automatic go-around mode and the speed selected on the flight mode control panel as the reference speed, and use the minimum selected speed of the aircraft as the lower limit of the reference speed.

[0010] Alternatively, the pitch angle control loop overload command generation unit may be further configured to: determine the dynamic upper limit of the first overload command based on the aircraft's current airspeed and minimum selectable speed, and limit the first overload command based on the dynamic upper limit.

[0011] Alternatively, it may also include a limit generation unit, which is used to generate an upper limit value of the second overload command based on the pitch angle limit and to generate a lower limit value of the second overload command based on the track tilt angle limit.

[0012] Alternatively, the limiting generation unit can be further configured to: when the second overload instruction exceeds the upper limit value, limit the second overload instruction to the upper limit value; when the second overload instruction is lower than the lower limit value, limit the second overload instruction to the lower limit value.

[0013] Alternatively, the overload instruction selection unit may include a fader, which is used to achieve a smooth transition of instructions during the switching from the first overload instruction to the second overload instruction.

[0014] Alternatively, the preset switching conditions may include at least: a second preset time or more has elapsed since entering the automatic go-around mode; or the second overload command is greater than the first overload command between the first preset time and the second preset time.

[0015] This disclosure provides an automatic go-around control method for an aircraft based on an overload control law, comprising the following steps: when the aircraft enters the automatic go-around mode, a reference pitch angle for the automatic go-around is generated based on the aircraft's state information, and a reference speed for the automatic go-around is generated based on the aircraft's speed information; a first overload command is generated based on the reference pitch angle and the aircraft's pitch information, and a second overload command is generated based on the reference speed and the aircraft's speed information; within a first preset time after the aircraft enters the automatic go-around mode, the first overload command is used as a go-around overload control command and output to the main flight control law of the flight control computer; after the first preset time, when a preset switching condition is met, the go-around overload control command is switched from the first overload command to the second overload command and output to the main flight control law of the flight control computer.

[0016] Alternatively, when generating the reference pitch angle for automatic go-around based on the aircraft's state information, the process may include: when the aircraft is in a twin-engine go-around state, using a fixed value as the reference pitch angle; and when the aircraft is in a single-engine go-around state, obtaining the reference pitch angle by interpolation based on the aircraft's flap angle and weight.

[0017] Alternatively, when generating a reference speed for automatic go-around based on the aircraft's speed information, the process may include: using the larger of the aircraft's speed when entering automatic go-around mode and the speed selected on the flight mode control panel as the reference speed, and using the aircraft's minimum selected speed as the lower limit of the reference speed.

[0018] Alternatively, when generating the first overload command, the process may include: determining the dynamic upper limit of the first overload command based on the aircraft's current airspeed and minimum selectable speed, and limiting the first overload command based on the dynamic upper limit.

[0019] Alternatively, it may also include: generating an upper limit value for the second overload command based on pitch angle limitations, and generating a lower limit value for the second overload command based on track tilt angle limitations.

[0020] Alternatively, it may also include: when the second overload instruction exceeds the upper limit value, limiting the second overload instruction to the upper limit value; when the second overload instruction is lower than the lower limit value, limiting the second overload instruction to the lower limit value.

[0021] Alternatively, a fader can be used to achieve a smooth transition of instructions during the switch from the first overload instruction to the second overload instruction.

[0022] Alternatively, the preset switching conditions may include at least: a second preset time or more has elapsed since entering the automatic go-around mode; or the second overload command is greater than the first overload command between the first preset time and the second preset time.

[0023] This disclosure provides an aircraft including the automatic go-around control device based on overload control law as described in any of the preceding claims.

[0024] Based on the above, this disclosure, by implementing phased output and switching control of the first and second overload commands during the automatic go-around process, helps to balance attitude establishment in the initial stage of go-around and subsequent speed maintenance, and improves the smoothness of automatic go-around control. This disclosure has at least the following beneficial effects:

[0025] This disclosure generates a first overload command and a second overload command respectively, and outputs the first overload command at the beginning of the automatic go-around and switches to output the second overload command after the preset switching conditions are met. This achieves phased output and switching control of overload control commands during the automatic go-around process, which is beneficial to balance attitude establishment at the beginning of the go-around and speed maintenance thereafter.

[0026] This disclosure, by employing different methods for determining the reference pitch angle in both twin-engine and single-engine go-around states, and by using the larger of the speed at which the automatic go-around mode is entered and the speed selected on the flight mode control panel as the reference speed, and by using the minimum selected speed as the lower limit, helps to make the settings of the reference pitch angle and reference speed more in line with the control requirements under different go-around conditions.

[0027] This disclosure determines the dynamic upper limit of the first overload command based on the aircraft's current airspeed and minimum selectable speed, and limits the amplitude of the first overload command based on the dynamic upper limit. This helps to suppress excessive pitch control demand in the early stages of go-around, thereby improving the safety of go-around control in low-energy states.

[0028] This disclosure generates upper and lower limits for the second overload command based on pitch angle and track tilt angle limits, and uses the upper and lower limits to constrain the second overload command, which is beneficial to balance speed control requirements and attitude / track boundary requirements during the speed control phase.

[0029] This disclosure achieves a smooth transition of commands by setting a fader during the switching process between the first overload command and the second overload command. This helps to reduce command abrupt changes caused by control phase switching and improves the stability of the automatic go-around process. Attached Figure Description

[0030] Figure 1 This is an overall architecture diagram of an automatic go-around control device according to one embodiment of the present disclosure.

[0031] Figure 2 This is a functional block diagram of an automatic go-around control device according to one embodiment of the present disclosure.

[0032] Figure 3 An architecture diagram for generating overload commands for a reference pitch angle control loop according to one embodiment of this disclosure is provided.

[0033] Figure 4 An architecture diagram for generating overload commands for a speed control loop according to one embodiment of this disclosure is provided.

[0034] Figure 5 This is a flowchart of an automatic go-around control method according to one embodiment of the present disclosure.

[0035] Figure 6 This is a flowchart illustrating the generation and switching of overload control commands for go-around according to one embodiment of this disclosure. Detailed Implementation

[0036] The automatic go-around control device and control method according to one embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are only used to illustrate the present disclosure and are not intended to limit the scope of protection of the present disclosure. Without departing from the concept of the present disclosure, those skilled in the art can make various modifications or substitutions to the following embodiments, and all such modifications or substitutions should fall within the scope of protection of the present disclosure.

[0037] like Figure 1As shown, the automatic go-around control system in an aircraft generally includes at least measuring equipment and other systems located on the aircraft and / or its body, a flight control computer, elevators and related actuators (hereinafter sometimes referred to as elevator actuators), an active throttle and related actuators, and engines and related actuators. The automatic go-around control device can be mainly located in the flight control computer and works in conjunction with the measuring equipment and other systems, the main flight control law, the automatic throttle control law, and related actuators to generate and output go-around overload control commands after the aircraft enters the automatic go-around mode.

[0038] In one embodiment of this disclosure, measuring devices and other systems installed on the aircraft and / or the aircraft body are used to provide the flight control computer with relevant input information required for automatic go-around control. The input information may include, for example, speed signals, overload signals, attitude information, navigation information, engine information, and flight control commands. After receiving the above information, the flight control computer generates the go-around overload control command and outputs it to the main flight control law; simultaneously, it generates throttle-related control signals through the automatic throttle control law, thereby forming thrust control adapted to the automatic go-around process.

[0039] Specifically, after receiving the go-around overload control command, the main flight control law generates an elevator angle signal and sends it to the elevator servo motor to drive the elevator, thereby applying corresponding aerodynamic forces to the aircraft and controlling it to complete pitch motion. Correspondingly, the automatic throttle control law outputs a throttle lever rate signal to the active throttle servo motor. After the active throttle servo motor drives the throttle lever, it outputs corresponding control commands to the engine via the engine electronic controller to adjust engine thrust. Thus, the automatic go-around control system can work together on the aircraft in terms of both pitch and thrust control to support the aircraft in establishing the flight state required for a go-around.

[0040] As can be seen from the overall architecture described above, the automatic go-around control device in this disclosure is mainly used to receive and utilize relevant information from measuring equipment and other systems to generate go-around overload control commands applicable to the main flight control law. It then coordinates the elevator and engine thrust through the main flight control law in conjunction with the automatic throttle control law. In other words, the automatic go-around control device does not operate independently of the aircraft's original flight control system, but rather as a control function component of the flight control computer, embedded in the overall automatic flight control architecture of the aircraft to generate and output go-around overload control commands during the automatic go-around process.

[0041] In subsequent implementations, based on the aforementioned overall system architecture, further integration will be achieved. Figure 2 The functional modules within the automatic go-around control device and their collaborative relationships are explained.

[0042] like Figure 2 As shown, in one embodiment of this disclosure, the automatic go-around control device may include a reference pitch angle generation unit, a reference speed generation unit, a pitch angle control loop overload command generation unit, a speed control loop overload command generation unit, a limiter generation unit, an overload command selection unit, and a fader. These units can be housed in the flight control computer and work collaboratively after the aircraft enters the automatic go-around mode to generate and output go-around overload control commands. In one embodiment of this disclosure, all the above units are located within the flight control computer; the reference pitch angle generation unit is connected to the pitch angle control loop overload command generation unit, the reference speed generation unit and the limiter generation unit are connected to the speed control loop overload command generation unit, and the pitch angle control loop overload command generation unit and the speed control loop overload command generation unit are respectively connected to the overload command selection unit.

[0043] [Reference Pitch Angle Generation Unit]

[0044] The reference pitch angle generation unit receives status information and generates a reference pitch angle based on that information. The status information may include, for example, the current aircraft engine operating status signal, the low-pass filter value of the aircraft flap angle, and the low-pass filter value of the aircraft weight, but is not limited to these; it can be any status that characterizes the relevant state used to determine the reference pitch angle during a go-around. The output signal of the reference pitch angle generation unit is the reference pitch angle for the aircraft's go-around, and this reference pitch angle can be used as input to the pitch angle control loop overload command generation unit to participate in the generation of the first overload command.

[0045] In some implementations, the reference pitch angle generation unit can determine the reference pitch angle for the aircraft during a go-around based on the engine operating status. Specifically, when the aircraft is in a twin-engine go-around configuration, a fixed value can be used as the reference pitch angle; when the aircraft is in a single-engine go-around configuration, the reference pitch angle can be determined based on the aircraft's flap angle and weight, for example, by interpolating the aircraft's flap angle and weight using a preset correspondence. This allows the determination of the reference pitch angle to adapt to the control requirements of different go-around conditions. In some implementations, the fixed value can be a pitch angle value preset for the twin-engine go-around configuration.

[0046] Furthermore, the selection of the fixed value can be determined through simulation analysis, for example, by combining the aircraft's aerodynamic characteristics, engine thrust characteristics, and control loop gain parameters. The fixed value needs to ensure a rapid establishment of climb attitude during the initial stage of automatic go-around, while also considering passenger comfort and speed boundary constraints during the go-around process. For example, if the fixed value is too large, the aircraft's pitch response may be too abrupt, affecting passenger comfort; if the fixed value is too small, under conditions of low weight and high engine thrust, the aircraft may accelerate too quickly, increasing the risk of approaching overspeed boundaries. Moreover, due to the differences in dynamic characteristics between different aircraft types and control loops, the fixed value can also be adjusted in conjunction with the dynamic matching relationship between control loops to improve the smoothness of the switch between the first and second overload commands during the go-around process.

[0047] [Pitch Angle Control Loop Overload Command Generation Unit]

[0048] The pitch angle control loop overload command generation unit is connected to the reference pitch angle generation unit and receives the aircraft's pitch information. The pitch information may include, for example, the current aircraft pitch angle and / or the current aircraft pitch rate. The pitch angle control loop overload command generation unit generates a first overload command based on the reference pitch angle and the pitch information. Thus, a first overload command branch corresponding to the reference pitch angle is established in the automatic go-around control device. This first overload command characterizes the aircraft's overload control requirements at the reference pitch angle level.

[0049] like Figure 3 As shown, in some embodiments, the pitch angle control loop overload command generation unit can collaboratively generate the first overload command through a reference pitch angle overload command generation module (not shown), a structural notch filter, and a limiting module. The input signals of the reference pitch angle overload command generation module may include the current aircraft pitch angle, the current aircraft's corrected airspeed complementary filter value, the current aircraft's vacuum airspeed complementary filter value, the current aircraft's pitch rate, the aircraft's minimum selectable speed, and the reference pitch angle for the aircraft's go-around. The output is the overload control command for the pitch angle control loop.

[0050] Figure 3In this system, the deviation between the reference pitch angle for the aircraft's go-around and the current pitch angle can be used as the basic input for pitch angle control, and the current pitch rate can be used as feedback to participate in the generation of the first overload command. Here, 1stLPF represents a first-order low-pass filter used to filter the input reference pitch angle signal; π / 180 represents the angle-to-radian conversion; Kθ represents the pitch angle error gain; Kq represents the pitch rate feedback gain; q represents the current aircraft pitch rate; TAS / g represents the conversion link based on vacuum speed and gravitational acceleration; Dynamic Saturation is equivalent to a dynamic limiting module; ξθ and ωθ characterize the damping and frequency-related parameters of the structural notch filter.

[0051] In some implementations, the reference pitch angle overload command generation module can generate commands according to formula (1):

[0052] Formula (1)

[0053] Where, N z,θ,cmd This represents the normal overload command output by the reference pitch angle control loop, characterizing the control requirements at the reference pitch angle level; θ ref The reference pitch angle for the aircraft's go-around; θ represents the current pitch angle of the aircraft; k θ θ represents the pitch deviation gain; q represents the current aircraft pitch rate; kq represents the pitch rate feedback gain; v represents the flight speed used for overload command conversion; g represents gravitational acceleration. ref -θ)·k θ The control action based on pitch angle deviation is used to characterize the damping term based on pitch angle rate feedback. The combination of the two is converted into the normal overload command by velocity and gravitational acceleration. Based on the above formula (1), the normal overload command, i.e. the first overload command, which characterizes the control requirements at the reference pitch angle level, can be calculated according to the relationship between the reference pitch angle of the aircraft during go-around and the current pitch state of the aircraft.

[0054] In some embodiments, the pitch angle control loop overload command generation unit may further include a structural notch filter, which is disposed after the reference pitch angle overload command generation module and is used to process the first overload command output by the reference pitch angle overload command generation module. The frequency and damping of the structural notch filter can be adjusted according to the aircraft airspeed. This suppresses structural modes that may be excited during control, thereby improving the stability of the first overload command output.

[0055] In some implementations, the pitch control loop overload command generation unit can also determine a dynamic upper limit for the first overload command based on the aircraft's current airspeed and minimum selectable speed, and limit the first overload command based on the dynamic upper limit. Specifically, as an example, the lower limit of the first overload command can be -0.3g, and the upper limit of the first overload command can be determined by a dynamic interpolation table adjusted according to the aircraft's airspeed and minimum selectable speed, with the upper limit being a maximum of 0.3g. Thus, the first overload command can be constrained when the aircraft is in a low-energy state, thereby suppressing excessive pitch control requirements during the initial go-around phase. In some implementations, the dynamic upper limit can be determined by a preset dynamic interpolation table based on the correspondence between the aircraft's current airspeed and minimum selectable speed.

[0056] Furthermore, the dynamic upper limit of the first overload command can be determined by combining engineering experience and simulation results, based on the difference between the current aircraft speed and the minimum selected speed, through a preset interpolation relationship. For example, when the current aircraft speed is significantly higher than the minimum selected speed, the dynamic upper limit can be appropriately increased; when the current aircraft speed is close to the minimum selected speed, the dynamic upper limit can be appropriately decreased. In some embodiments, when the current aircraft speed is higher than the minimum selected speed preset margin, the dynamic upper limit can be, for example, 0.3g; when the current aircraft speed is close to the minimum selected speed, the dynamic upper limit can be, for example, 0.2g. This helps to suppress excessive pitch control demand under low energy conditions, thereby reducing the risk of excessive underspeed or prolonged underspeed during go-around. The specific value of the dynamic upper limit can also be adjusted in combination with the characteristics of the aircraft and engine, as well as the dynamic characteristics of the control system.

[0057] [Reference Velocity Generation Unit]

[0058] The reference speed generation unit receives speed information and generates a reference speed based on that information. The speed information may include, for example, the aircraft's minimum selectable speed (VLS), aircraft engine operating status, aircraft maximum speed limit (VMax), aircraft corrected airspeed complementary filter value, aircraft activation go-around mode signal, and equivalent corrected airspeed value selected on the flight mode control panel, but is not limited to these. Any relevant speed quantity that can characterize the aircraft's current flight speed state and be used to determine the reference speed for go-around can be used as the speed information. The output of the reference speed generation unit is the aircraft's go-around reference speed, and this reference speed can be used as input to the speed control loop overload command generation unit to participate in the generation of the second overload command.

[0059] In some implementations, the reference speed generation unit can use the larger of the airspeed at the time of the go-around and the equivalent airspeed selected by the flight mode control panel as the reference speed for automatic go-around. The go-around time can be determined by the aircraft activating the go-around mode signal. Simultaneously, the minimum selectable speed (VLS) is selected as the lower limit of the automatic go-around reference speed. This allows the reference speed to take into account both the current flight status and the preset speed requirements during automatic go-around.

[0060] [Speed ​​Control Loop Overload Command Generation Unit]

[0061] The speed control loop overload command generation unit is connected to the reference speed generation unit and receives the aircraft's speed information. The speed control loop overload command generation unit generates a second overload command based on the reference speed and the speed information. Thus, a second overload command branch corresponding to the reference speed is established in the automatic go-around control device. This second overload command characterizes the aircraft's overload control requirements at the reference speed level.

[0062] In some embodiments, the inputs to the speed control loop overload command generation unit may include the current aircraft's flight path angle, roll angle, pitch angle, pitch rate, corrected airspeed complementary filter value, real airspeed complementary filter value, high-pass filter value for longitudinal estimated overload, estimated normal overload value, low-pass filter value for flap angle, and reference airspeed for go-around. The reference airspeed for go-around is the reference speed output by the aforementioned reference speed generation unit. The output of the speed control loop overload command generation unit is an overload command for speed control functions, i.e., a second overload command.

[0063] like Figure 4 As shown, in some embodiments, the speed control loop overload command generation unit may include a reference speed control overload command generation module, and may further include a filtering module disposed in the unit for processing the input or feedback quantity. The reference speed control overload command generation module is used to generate a second overload command based on the speed deviation between the target corrected airspeed and the current aircraft corrected airspeed, and in combination with the rate of change of the current aircraft corrected airspeed.

[0064] Specifically, Figure 4 CAS in Target The target corrected airspeed is indicated, which may correspond to the reference speed output by the aforementioned reference speed generation unit. CAS represents the current corrected airspeed of the aircraft. Dot N represents the current corrected airspeed rate of change of the aircraft. zCMD,SPD This indicates an overload command used for speed control, i.e., the second overload command. N zThe LimitModule is equivalent to a limit generation unit. The target corrected airspeed and the current aircraft corrected airspeed can be compared first to obtain a speed deviation signal. The speed deviation signal can be processed by gain to form the main control quantity. The rate of change of the current aircraft corrected airspeed can be used as a feedback quantity to participate in the generation of the second overload command. With the above settings, the speed control loop overload command generation unit can generate a second overload command for go-around control based on the go-around reference speed and the current airspeed state of the aircraft.

[0065] In some implementations, to prevent sudden changes in the reference speed input from adversely affecting the generation of the second overload command, the go-around reference speed input can be filtered. Furthermore, the current corrected airspeed change rate of the aircraft can also be high-pass filtered before participating in the generation of the second overload command. The generated second overload command can be further constrained by upper and lower limits before output, thus limiting it to a preset range. This improves the smoothness of the second overload command output while also considering the control boundary requirements during the go-around process.

[0066] [Amplitude Limiting Generation Unit]

[0067] The amplitude limiting generation unit is used to limit the second overload command. Specifically, the amplitude limiting generation unit generates an upper limit value for the second overload command based on the pitch angle limit and a lower limit value for the second overload command based on the track tilt angle limit. This provides boundary constraints for the second overload command. In some embodiments, when the second overload command exceeds the upper limit value, it can be limited to the upper limit value; when the second overload command is lower than the lower limit value, it can be limited to the lower limit value. Thus, the second overload command is subject to corresponding boundary constraints before output, balancing speed control requirements with attitude and trajectory limitation requirements.

[0068] In some embodiments, the limiting generation unit may be a speed control loop overload command limiting generation unit. The input signals of the speed control loop overload command limiting generation unit may include the current aircraft's track inclination limit, current aircraft roll angle limit, current aircraft pitch angle limit, current aircraft pitch rate limit, current aircraft corrected airspeed complementary filter value, current aircraft free airspeed complementary filter value, high-pass filter value for longitudinal estimated overload, limit value for normal estimated overload, low-pass filter value for flap angle, and reference airspeed for go-around. The output of the speed control loop overload command limiting generation unit includes the limit value of the speed control loop overload command, i.e., the upper and lower limits of the second overload command.

[0069] In some implementations, the upper limit of the speed control loop overload command can be the overload command corresponding to a fixed pitch angle, obtained by formula (1). The upper limit can be determined based on the correspondence between the fixed pitch angle and the overload. To improve the stability of the upper limit generation process, a structural notch filter can be set in the upper limit generation path. The frequency and damping of the structural notch filter can be adjusted according to the aircraft airspeed. Thus, an upper boundary constraint can be provided for the second overload command while meeting the pitch angle limitation requirements.

[0070] In some implementations, the lower limit of the speed control loop overload command can be the overload command corresponding to a fixed track inclination angle. To improve the stability of the lower limit generation process, a notch filter can be placed in the lower limit generation path. The damping of the notch filter can be a fixed value, the frequency can be adjusted according to the aircraft airspeed, and the gain can be adjusted according to the aircraft flap status and aircraft airspeed. Thus, a lower boundary constraint can be provided for the second overload command while meeting the track inclination angle limitation requirements.

[0071] In some implementations, formula (2) can be used to generate overload commands for the speed control loop:

[0072] Formula (2)

[0073] Where, N Z,SPD,CMD CAS indicates the overload command output by the speed control loop. REF This represents the reference corrected airspeed, which corresponds to the reference speed output by the aforementioned reference speed generation unit. CAS represents the current corrected airspeed. dot This represents the rate of change of the current corrected airspeed, with KV1 and KV2 being gain coefficients. This formula generates an overload command for the speed control loop by weighting the deviation between the reference corrected airspeed and the current corrected airspeed and dynamically correcting it using the rate of change of the corrected airspeed.

[0074] Specifically, CAS REF - CAS reflects the deviation of the current aircraft speed from the target speed. This deviation, weighted by the gain coefficient KV1, characterizes the basic correction required based on the speed error. dot Reflecting the current trend of aircraft speed change, the speed change rate term is introduced into the basic correction amount to dynamically compensate for the speed change process, thereby suppressing overshoot and oscillation; the gain coefficient KV2 is used to adjust the intermediate amount after correction as a whole to obtain the overload command output that meets the control requirements. Thus, formula (2) can not only correct the deviation between the target speed and the current airspeed, but also improve the smoothness and stability of the control response by combining the current airspeed change trend of the aircraft, which is beneficial to balance speed tracking performance and passenger comfort during go-around.

[0075] Although those skilled in the art will understand, it is briefly stated here that the reference pitch angle control loop normal overload command output by formula (1) is the first overload command referred to herein. The speed control loop overload command output by formula (2) is the second overload command referred to herein. Wherein, the reference speed in the speed control loop can be expressed as the reference airspeed. Figure 4 And in the formula, it is expressed as the target corrected airspeed (CAS). Target and Reference Corrected Airspeed (CAS) REF .

[0076] Therefore, this disclosure establishes two control branches corresponding to the first and second overload commands by separately setting up a reference pitch angle generation unit, a reference velocity generation unit, a pitch angle control loop overload command generation unit, and a velocity control loop overload command generation unit, and provides boundary constraints for the second overload command through a limiting generation unit. The first and second overload commands correspond to the reference pitch angle branch and the reference velocity branch, respectively, and are selected and output in subsequent stages through an overload command selection unit.

[0077] [Overload Command Selection Unit]

[0078] The overload command selection unit is connected to both the pitch control loop overload command generation unit and the speed control loop overload command generation unit. It receives the first overload command and the second overload command, and outputs a go-around overload control command. In some embodiments, the input to the overload command selection unit may also include an aircraft go-around mode activation signal and the upper and lower limits of the second overload command. Therefore, the overload command selection unit can select either the first or second overload command as the go-around overload control command output based on the aircraft's current go-around phase and the relationship between the first and second overload commands.

[0079] In some implementations, within a first preset time after the aircraft's go-around time, the go-around overload control command output by the overload command selection unit can be set to the first overload command to ensure that the aircraft can quickly pull up its nose and establish a climb gradient after the go-around begins. In some implementations, the first preset time may be, for example, 3 seconds.

[0080] In some implementations, the preset switching condition includes at least one of the following: a second preset time has elapsed since the aircraft entered automatic go-around mode; or, between the first preset time and the second preset time, the second overload command is greater than the first overload command. In some implementations, the second preset time may be 8 seconds.

[0081] In some implementations, after the first preset time and within a second preset time since the aircraft entered automatic go-around mode, the overload command selection unit can compare the magnitudes of the second overload command and the first overload command. When the second overload command is greater than the first overload command, the overload command selection unit can switch the go-around overload control command from the first overload command to the second overload command; when the second overload command is not greater than the first overload command, the overload command selection unit can continue to output the first overload command as the go-around overload control command. Thus, when speed control demand begins to dominate, control can be switched to the second overload command.

[0082] In some implementations, when more than a second preset time has elapsed since the aircraft entered the automatic go-around mode, the overload command selection unit can output the second overload command as a go-around overload control command.

[0083] The diffuser can be configured in conjunction with the overload command selection unit to achieve a smooth transition of commands during the switch from the first overload command to the second overload command. Specifically, in some embodiments, when the second overload command is greater than the first overload command between the first preset time and the second preset time, or when more than the second preset time has elapsed since the aircraft entered the automatic go-around mode, the go-around overload control command can be gradually transitioned from the first overload command to the second overload command via the diffuser. By setting the diffuser, the abrupt change in commands caused by the switch between different control stages can be reduced, improving the smoothness of the automatic go-around process.

[0084] As can be seen, this disclosure establishes two command branches based on the reference pitch angle and reference speed, thus prioritizing the output of the first overload command in the initial stage of automatic go-around, and switching to the output of the second overload command in the subsequent stage. By combining the dynamic limiting of the first overload command, the upper and lower limit boundary constraints of the second overload command, and the smooth transition of the desiccant, the phased output and smooth switching of the go-around overload control command in the automatic go-around process are realized.

[0085] The following combination Figure 5 and Figure 6 This document provides a detailed description of an automatic go-around control method for aircraft based on an overload control law, according to one embodiment of the present disclosure. It should be understood that the following method implementation can be executed by the aforementioned automatic go-around control device, and in particular by the coordinated implementation of a reference pitch angle generation unit, a reference speed generation unit, a pitch angle control loop overload command generation unit, a speed control loop overload command generation unit, a limiter generation unit, an overload command selection unit, and a de-escalator in a flight control computer.

[0086] like Figure 5As shown, in some embodiments, the automatic go-around control method based on the overload control law may include the following steps: S1, when the aircraft enters the automatic go-around mode, acquire the input information required for automatic go-around control; S2, generate a reference pitch angle for automatic go-around based on the aircraft's state information, and generate a reference speed for automatic go-around based on the aircraft's speed information; S3, generate a first overload command based on the reference pitch angle and the aircraft's pitch information, and generate a second overload command based on the reference speed and the aircraft's speed information; S4, within a first preset time after the aircraft enters the automatic go-around mode, output the first overload command as a go-around overload control command to the main flight control law; S5, after the first preset time and when the preset switching conditions are met, switch the go-around overload control command from the first overload command to the second overload command, and output it to the main flight control law. Thus, the aircraft can prioritize establishing a pitch-up attitude in the initial stage of automatic go-around, and simultaneously consider speed tracking requirements in subsequent stages, thereby achieving automatic go-around control.

[0087] In S1, when the aircraft enters the automatic go-around mode, the input information required for automatic go-around control is acquired. This input information may include aircraft status information, speed information, pitch information, and other information related to automatic go-around control. The specific content of the input information can be found in the description of the input information for the automatic go-around control system in the aforementioned device embodiment, and will not be repeated here. The acquired input information can be filtered, converted, or estimated before being used for subsequent automatic go-around control.

[0088] In S2, a reference pitch angle for automatic go-around is generated based on the aircraft's state information, and a reference speed for automatic go-around is generated based on the aircraft's speed information. This provides target quantities for the subsequent generation of the first and second overload commands, respectively.

[0089] In some implementations, generating the reference pitch angle may include: using a fixed value as the reference pitch angle when the aircraft is in a twin-engine go-around configuration; or obtaining the reference pitch angle by interpolation based on the aircraft's flap angle and weight when the aircraft is in a single-engine go-around configuration.

[0090] In some implementations, generating the reference speed may include: using the larger of the speed at which the aircraft enters automatic go-around mode and the speed selected on the flight mode control panel as the reference speed, and using the minimum selected speed of the aircraft as the lower limit of the reference speed.

[0091] In S3, a first overload command is generated based on the reference pitch angle and the aircraft's pitch information, and a second overload command is generated based on the reference speed and the aircraft's speed information. The first overload command characterizes the aircraft's overload control requirements under the reference pitch angle constraint, and the second overload command characterizes the aircraft's overload control requirements under the reference speed constraint.

[0092] In some implementations, when generating the first overload command, a dynamic upper limit for the first overload command can be determined based on the aircraft's current airspeed and minimum selectable speed, and the first overload command can be limited based on the dynamic upper limit.

[0093] In some implementations, when generating the second overload command, an upper limit value for the second overload command can be generated based on a pitch angle limit, and a lower limit value for the second overload command can be generated based on a track tilt angle limit. When the second overload command exceeds the upper limit value, the second overload command is limited to the upper limit value; when the second overload command is lower than the lower limit value, the second overload command is limited to the lower limit value. Thus, while controlling based on reference speed, both aircraft attitude and trajectory limitations can be considered.

[0094] In S4, within a first preset time period after the aircraft enters the automatic go-around mode, the first overload command is output as the go-around overload control command to the main flight control law. This allows the aircraft to establish a pitch-up attitude based on the reference pitch angle during the initial stage of the automatic go-around, thus facilitating the rapid establishment of a climb gradient after the go-around begins. In some embodiments, the first preset time period can be 3 seconds.

[0095] In S5, after a first preset time and when preset switching conditions are met, the go-around overload control command is switched from the first overload command to the second overload command and output to the main flight control law. The preset switching conditions include at least one of the following: more than a second preset time has elapsed since the aircraft entered automatic go-around mode; or, between the first and second preset times, the second overload command is greater than the first overload command. In some embodiments, the second preset time may be 8 seconds. Therefore, the first overload command output can be maintained preferentially in the initial stage of automatic go-around, and in subsequent stages, the output can be switched to the second overload command based on the go-around duration or the magnitude relationship between the first and second overload commands.

[0096] Combination Figure 6Further explanation of S3 to S5: In S3, a first overload command and a second overload command are generated, and upper and lower limit constraints are imposed on the second overload command. In S4, it is determined whether the flight is within a first preset time period. In S5, it is determined whether the preset switching conditions are met. Specifically, if the flight is within the first preset time period (Yes in the diagram), the first overload command is output as a go-around overload control command. If the flight is not within the first preset time period (No in the diagram), it is further determined whether the flight is within a second preset time period. If the flight is still within the second preset time period (Yes in the diagram), the magnitudes of the second overload command and the first overload command are further compared; if the second overload command is greater than the first overload command (Yes in the diagram), the second overload command is output as a go-around overload control command; if the second overload command is not greater than the first overload command (No in the diagram), the first overload command continues to be output as a go-around overload control command. If the second preset time has exceeded since the aircraft entered the automatic go-around mode (No in the diagram), the second overload command is output as a go-around overload control command. This allows the selection of go-around overload control commands between different go-around phases to better match the aircraft's current flight status and control requirements.

[0097] In some implementations, a transitional fusion of go-around overload control commands can be achieved through a diffuser during the switch from the first overload command to the second overload command. Specifically, the diffuser can receive the first and second overload commands and output the go-around overload control commands according to the current go-around phase of the aircraft. During the switch from the first to the second overload command, the diffuser can weight the first and second overload commands, allowing the go-around overload control commands to gradually transition from the first to the second overload command. This reduces the abrupt changes in commands caused by the switch between different control phases and improves the smoothness of the automatic go-around process.

[0098] In some implementations, after the go-around overload control command is output to the main flight control law, the main flight control law can further generate elevator control inputs to control the aircraft to complete longitudinal attitude adjustments; simultaneously, the autothrottle control law can output throttle control inputs adapted to the automatic go-around to adjust engine thrust. Thus, automatic go-around can be achieved through the synergistic effect of overload control and thrust control.

[0099] Therefore, this disclosure, by establishing a first overload command generation mechanism based on the reference pitch angle and a second overload command generation mechanism based on the reference speed, enables automatic go-around control to move beyond a single control command and adopt different control priorities for different go-around phases. In the initial stage of automatic go-around, by outputting the first overload command as the go-around overload control command within a first preset time period, the aircraft can prioritize establishing a pitch-up climb attitude based on the reference pitch angle, thus facilitating the rapid establishment of a climb gradient after the go-around begins. In subsequent stages, by switching the go-around overload control command to the second overload command when preset switching conditions are met, the aircraft can further control itself based on the reference speed, thus facilitating the maintenance of subsequent speed requirements. Meanwhile, by dynamically limiting the first overload command based on the aircraft's current airspeed and minimum selectable speed, excessive pitch control demands in low-energy states can be suppressed, reducing the risk of underspeed. By imposing upper and lower limits on the second overload command based on pitch angle and track tilt angle limits, attitude and trajectory boundary requirements can be considered during the speed control phase, reducing the risk of exceeding the flight envelope. Furthermore, by using a fader to transition and fuse the first and second overload commands, the go-around overload control command can gradually transition from the first to the second overload command, thereby reducing command abrupt changes caused by switching between different control phases. Thus, this disclosure can balance initial attitude establishment, subsequent speed maintenance, boundary constraints, and switching smoothness during automatic go-around, thereby improving the overall performance of automatic go-around control.

[0100] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of this disclosure. It should be understood that the above are merely one specific embodiment of this disclosure and are not limited to the scope of protection of this disclosure. This disclosure can be embodied in various forms without departing from its fundamental characteristics. Therefore, the embodiments described in this disclosure are for illustrative purposes only and not for limitation. Since the scope of this disclosure is defined by the claims rather than the specification, all changes falling within the scope defined by the claims, or their equivalents, should be understood to be included in the claims. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. An automatic go-around control device based on an overload control law, characterized in that, include: The reference pitch angle generation unit is used to generate the reference pitch angle for automatic go-around based on the aircraft's state information after the aircraft enters the automatic go-around mode. The reference speed generation unit is used to generate a reference speed for the aircraft's automatic go-around based on the aircraft's speed information after the aircraft enters the automatic go-around mode. A pitch angle control loop overload command generation unit, which is connected to the reference pitch angle generation unit, is used to generate a first overload command based on the reference pitch angle and the aircraft's pitch information. A speed control loop overload command generation unit, which is connected to the reference speed generation unit, is used to generate a second overload command based on the reference speed and the aircraft's speed information; The overload command selection unit has its input terminals connected to the pitch angle control loop overload command generation unit and the speed control loop overload command generation unit, respectively, and its output terminal outputs a go-around overload control command to the main flight control law of the flight control computer. The overload command selection unit is configured to: output the first overload command as the go-around overload control command to the main flight control law within a first preset time after the aircraft enters the automatic go-around mode; and after the first preset time, when the preset switching conditions are met, switch the first overload command to the second overload command and output it to the main flight control law to control the aircraft to complete the automatic go-around.

2. The automatic go-around control device based on overload control law according to claim 1, characterized in that, The reference pitch angle generation unit is further configured as follows: When the aircraft is in a twin-engine go-around state, a fixed value is used as the reference pitch angle; When the aircraft is in a single-engine go-around state, the reference pitch angle is determined based on the aircraft's flap angle and weight.

3. The automatic go-around control device based on overload control law according to claim 1, characterized in that, The reference velocity generation unit is further configured as follows: The reference speed is the greater of the speed at which the aircraft enters automatic go-around mode and the speed selected on the flight mode control panel, and the minimum selected speed of the aircraft is used as the lower limit of the reference speed.

4. The automatic go-around control device based on overload control law according to claim 1, characterized in that, The pitch angle control loop overload command generation unit is further configured as follows: Based on the aircraft's current airspeed and minimum selectable speed, the dynamic upper limit of the first overload command is determined, and the first overload command is limited based on the dynamic upper limit.

5. The automatic go-around control device based on overload control law according to claim 1, characterized in that, It also includes a limiting generation unit. The amplitude limiting generation unit is used to generate an upper limit value of the second overload command based on the pitch angle limitation, and to generate a lower limit value of the second overload command based on the track tilt angle limitation.

6. The automatic go-around control device based on overload control law according to claim 5, characterized in that, The limiting generation unit is further configured as follows: When the second overload command exceeds the upper limit value, the second overload command is limited to the upper limit value; When the second overload command is lower than the lower limit value, the second overload command is restricted to the lower limit value.

7. The automatic go-around control device based on overload control law according to claim 1, characterized in that, The overload command selection unit includes: A fader is used to achieve a smooth transition of instructions during the switching from the first overload instruction to the second overload instruction.

8. The automatic go-around control device based on overload control law according to claim 1, characterized in that, The preset switching conditions include at least the following: More than the second preset time has elapsed since entering automatic go-around mode; or Between the first preset time and the second preset time, the second overload instruction is greater than the first overload instruction.

9. An automatic go-around control method for aircraft based on overload control law, characterized in that, Includes the following steps: When the aircraft enters the automatic go-around mode, a reference pitch angle for the automatic go-around is generated based on the aircraft's state information, and a reference speed for the automatic go-around is generated based on the aircraft's speed information. Based on the reference pitch angle and the aircraft's pitch information, a first overload command is generated, and based on the reference speed and the aircraft's speed information, a second overload command is generated. Within the first preset time after the aircraft enters the automatic go-around mode, the first overload command is output to the main flight control law of the flight control computer as the go-around overload control command. After the first preset time, when the preset switching conditions are met, the go-around overload control command is switched from the first overload command to the second overload command and output to the main flight control law of the flight control computer.

10. The automatic go-around control method for aircraft based on overload control law according to claim 9, characterized in that, When generating the reference pitch angle for automatic go-around based on the aircraft's state information, the following is included: When the aircraft is in a twin-engine go-around state, a fixed value is used as the reference pitch angle; When the aircraft is in a single-engine go-around state, the reference pitch angle is obtained by interpolation based on the aircraft's flap angle and weight.

11. The automatic go-around control method for aircraft based on overload control law according to claim 9, characterized in that, When generating the reference speed for automatic go-around based on the aircraft's speed information, the following is included: The reference speed is the greater of the speed at which the aircraft enters automatic go-around mode and the speed selected on the flight mode control panel, and the minimum selected speed of the aircraft is used as the lower limit of the reference speed.

12. The automatic go-around control method for aircraft based on overload control law according to claim 9, characterized in that, When generating the first overload instruction, the following are included: Based on the aircraft's current airspeed and minimum selectable speed, the dynamic upper limit of the first overload command is determined, and the first overload command is limited based on the dynamic upper limit.

13. The automatic go-around control method for aircraft based on overload control law according to claim 9, characterized in that, It also includes: generating an upper limit value for the second overload command based on pitch angle limits, and generating a lower limit value for the second overload command based on track tilt angle limits.

14. The automatic go-around control method for aircraft based on overload control law according to claim 13, characterized in that, It also includes: when the second overload command exceeds the upper limit value, limiting the second overload command to the upper limit value; When the second overload command is lower than the lower limit value, the second overload command is restricted to the lower limit value.

15. The automatic go-around control method for aircraft based on overload control law according to claim 9, characterized in that, During the transition from the first overload instruction to the second overload instruction, a fader is used to achieve a smooth transition of the instruction.

16. The automatic go-around control method for aircraft based on overload control law according to claim 9, characterized in that, The preset switching conditions include at least the following: More than the second preset time has elapsed since entering automatic go-around mode; or Between the first preset time and the second preset time, the second overload instruction is greater than the first overload instruction.

17. An aircraft, characterized in that, Includes an automatic go-around control device based on an overload control law as described in any one of claims 1 to 8.

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