A method for testing the stability margin of a distributed fly-by-wire flight control system

Abstract

This invention discloses a stability margin testing method for a distributed fly-by-wire flight control system, relating to the field of flight control system testing technology. The stability margin testing system for this distributed fly-by-wire flight control system includes a flight control computer, actuator control electronics, actuator servo controllers, actuators, control surfaces, a digital-to-analog converter module, and a frequency response analyzer. The stability margin testing method for this distributed fly-by-wire flight control system achieves the conversion and output of digital and analog signals by adding or retrieving digital-to-analog converter modules and analog-to-digital converter modules. It also acquires flight control commands and excitation signals from the frequency response analyzer, modifies the calculation logic of the actuator servo controller to superimpose the excitation signals and flight control commands, transmits the superimposed commands to the actuators, and simultaneously returns them to the digital-to-analog converter module. The digital-to-analog converter module converts the digital signals into analog signals and transmits them to the frequency response analyzer to calculate the stability margin.

Description

Technical Field

[0001] This invention relates to the field of experimental testing technology for distributed flight control systems, specifically a method for testing the stability margin of a distributed fly-by-wire flight control system. Background Technology

[0002] Early fly-by-wire flight control systems employed a centralized architecture. The actuator control electronics or flight control computer (fly-by-wire flight control systems have various architectures; some directly issue commands to control the actuators, while others transmit commands to the actuator control electronics, which then control the actuators) directly generate the actuator control commands (current signals) and collect the actuator feedback signals (voltage signals) to achieve servo control. To transmit the various excitation signals required for a single actuator and collect the feedback signals, at least 19 wires were needed to form a cable. For large transport aircraft, the distance from the flight control computer / actuator control electronics to the actuators is long, and the numerous long cables increase the weight of the entire aircraft wiring harness. Longer cables increase resistance, which attenuates the signal and makes it susceptible to interference. Furthermore, the large number of cables increases the probability of actuator control failure due to the increased likelihood of cable damage.

[0003] To address the aforementioned issues, the distributed fly-by-wire flight control system separates the actuator servo control function from the actuator control electronics or flight control computer, transferring the servo control function to a dedicated actuator servo controller. The actuator servo controller is directly installed on the actuator, and digital signals are transmitted between the flight control computer or actuator control electronics and the actuator servo controller. This increases the anti-interference capability of signal transmission, reduces the signal transmission failure rate, and reduces the number and weight of signal transmission cables. However, because the information-rich digital signals are transmitted between the actuator control electronics or flight control computer and the actuator servo controller, the traditional method of modifying the actuator control current signal to conduct stability margin tests is difficult to implement.

[0004] The purpose of stability margin testing is to determine that the flight control system has sufficient amplitude margin and phase margin to prevent the flight control system from becoming unstable due to factors such as aging of feedback sensors and changes in flight configuration affecting the parameters of the flight control system.

[0005] Stability margin testing requires treating the complete closed-loop control system as an open-loop system. This involves extracting the input-output data of the open-loop system under normal operating conditions and analyzing the amplitude and phase relationship of the output signal relative to the input signal to obtain the stability margin value. Typically, this extraction is performed at the actuator's control command input. In a distributed architecture, the actuator servo controller is directly connected to the actuator, and the servo controller receives digital signals. Therefore, it's impossible to directly superimpose the excitation signal provided by the frequency response analyzer into the actuator. Furthermore, the frequency response analyzer cannot directly perform stability margin analysis on digital signals. To address this, we propose a stability margin testing method for distributed fly-by-wire flight control systems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a stability margin testing method for a distributed fly-by-wire flight control system. This method solves the problems that the actuator servo controller is directly connected to the actuator, and the actuator servo controller receives digital signals, making it impossible to directly superimpose the excitation signals provided by the frequency response analyzer into the actuator. At the same time, the frequency response analyzer cannot directly perform stability margin analysis on digital signals.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a stability margin testing system for a distributed fly-by-wire flight control system, comprising:

[0008] A flight control computer, which is used to perform control rate parameter calculations and logic processing;

[0009] Actuator control electronics, which are connected to the flight control computer;

[0010] An actuator servo controller is connected to a flight control computer and brake control electronics. The actuator servo controller is used to receive signals from the flight control computer and the actuator control electronics.

[0011] An actuator is connected to an actuator servo controller, and the actuator receives signals from the actuator servo controller and performs the operation.

[0012] An operating surface, connected to another operating surface, is used to control the actuator;

[0013] A digital-to-analog conversion module, wherein multiple digital-to-analog conversion modules are configured;

[0014] An analog-to-digital converter module is connected to an actuator servo controller. The digital-to-analog converter module and the analog-to-digital converter module are used to convert digital signals to analog signals and output them.

[0015] A frequency response analyzer is connected to a digital-to-analog converter module and an analog-to-digital converter module, and the frequency response analyzer performs stability margin analysis on digital signals.

[0016] Preferred, including:

[0017] A flight control computer, which is used to perform control rate parameter calculations and logic processing;

[0018] Actuator control electronics, which are connected to the flight control computer, and which serve as a backup computer for the flight control computer;

[0019] An actuator servo controller is connected to a flight control computer and brake control electronics. The actuator servo controller is used to receive signals from the flight control computer and the actuator control electronics.

[0020] An actuator is connected to an actuator servo controller, and the actuator receives signals from the actuator servo controller and performs the operation.

[0021] An operating surface, connected to another operating surface, is used to control the actuator;

[0022] A digital-to-analog conversion module, wherein multiple digital-to-analog conversion modules are configured;

[0023] An analog-to-digital converter module is connected to an actuator servo controller. The digital-to-analog converter module and the analog-to-digital converter module are used to convert digital signals to analog signals and output them.

[0024] A frequency response analyzer, which is connected to a digital-to-analog converter module and an analog-to-digital converter module, performs stability margin analysis on digital signals;

[0025] An integrated circuit board is used for modular integration and installation of an actuator servo controller, a digital-to-analog converter module, and an analog-to-digital converter module.

[0026] Preferably, the actuator control electronics is a backup computer for the flight control computer.

[0027] Preferably, the actuator servo controller is used to understand the digital signals provided by the upstream flight control computer or actuator control electronics, and the actuator servo controller processes and converts the specified control command signals and excitation signals by adjusting the internal logic.

[0028] Preferably, one set of the digital-to-analog conversion modules is connected to the flight control computer and the primary brake control electronics, while the other set of the digital-to-analog conversion modules is connected to the actuator servo controller.

[0029] Preferably, the actuator servo controller is used to determine whether the control command has been tampered with during the transmission from the flight control computer to the actuator servo controller, and the determination method of the actuator servo controller is a data verification algorithm.

[0030] Preferably, the actuator control electronics are used to superimpose control command signals, enabling communication monitoring between the flight control computer and the actuator servo controller.

[0031] This invention also provides a stability margin testing method for a distributed fly-by-wire flight control system, comprising the following steps: the actuator control electronics transmits instructions from the flight control computer to the actuator servo controller; the actuator servo controller uses a data verification algorithm to confirm whether the control instructions have been tampered with during transmission from the flight control computer to the actuator servo controller; the actuator servo controller superimposes the excitation signal with the flight instructions and transmits the superimposed instructions to the actuator; simultaneously, the instructions are returned to the digital-to-analog converter module, which converts the digital signal into an analog signal and transmits it to the frequency response analyzer; the frequency response analyzer calculates the stability margin; then, the frequency response analyzer transmits the excitation signal to the actuator servo controller through the analog-to-digital converter module, and finally injects it into the actuator.

[0032] This invention discloses a stability margin testing method for a distributed fly-by-wire flight control system, which has the following beneficial effects:

[0033] The stability margin testing method for this distributed fly-by-wire flight control system involves adding or retrieving a digital-to-analog converter (DAC) and an analog-to-digital converter (ADC) to the actuator servo controller to convert and output digital signals to analog signals. It also acquires flight control commands and excitation signals from the frequency response analyzer, modifies the actuator servo controller's calculation logic to superimpose the excitation signals and flight control commands, transmits the superimposed commands to the actuator, and simultaneously returns them to the DAC module. The DAC module then converts the digital signals to analog signals and transmits them to the frequency response analyzer to calculate the stability margin. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of Embodiment 2 of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] This application provides a stability margin testing method for a distributed fly-by-wire flight control system. It addresses the problem that the actuator servo controller is directly connected to the actuator, and since the servo controller receives digital signals, it cannot directly superimpose the excitation signal provided by the frequency response analyzer into the actuator. Furthermore, the frequency response analyzer cannot directly perform stability margin analysis on digital signals. The method adds or calls a digital-to-analog converter (DAC) and an analog-to-digital converter (ADC) to the actuator servo controller's own functions to achieve digital-to-analog signal conversion and output. It also collects flight control commands and excitation signals from the frequency response analyzer, modifies the actuator servo controller's calculation logic to superimpose the excitation signal and flight control commands, transmits the superimposed command to the actuator, and simultaneously returns it to the DAC module. The DAC module converts the digital signal into an analog signal and transmits it to the frequency response analyzer, thus calculating the stability margin.

[0039] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0040] Embodiment 1 of the present invention discloses a stability margin testing system for a distributed fly-by-wire flight control system.

[0041] According to the appendix Figure 1 ,include:

[0042] Flight control computer, used for calculating control rate parameters and performing logical processing;

[0043] Actuator control electronics, which are connected to the flight control computer;

[0044] The actuator servo controller is connected to the flight control computer and the brake control electronics. The actuator servo controller is used to receive signals from the flight control computer and the actuator control electronics.

[0045] The actuator is connected to the actuator servo controller. The actuator receives signals from the actuator servo controller and performs the actions.

[0046] Operating surfaces, connected to each other, are used to control the actuators;

[0047] The digital-to-analog conversion module has multiple configurations.

[0048] The analog-to-digital converter module is connected to the actuator servo controller. The digital-to-analog converter module and the analog-to-digital converter module are used to convert digital signals to analog signals and output them.

[0049] The frequency response analyzer is connected to the digital-to-analog converter module and the analog-to-digital converter module. The frequency response analyzer performs stability margin analysis on digital signals.

[0050] Installing the digital-to-analog (D / A) converter and analog-to-digital (A / D) converter externally to the actuator servo controller offers greater flexibility. This allows for independent replacement or upgrades of the D / A and A / D converters to adapt to different system requirements without affecting the actuator servo controller. It also facilitates modular system design, making system design and maintenance more flexible. The D / A and A / D converters can be replaced or adjusted as needed without altering the entire actuator servo controller. Furthermore, external installation provides better isolation between the power supply and signals, reducing interference caused by grounding or power supply noise, especially when isolation between the D / A and A / D converters and noise-sensitive equipment is required.

[0051] Embodiment 2 of the present invention discloses a stability margin testing system for a distributed fly-by-wire flight control system.

[0052] According to the appendix Figure 2 ,include:

[0053] Flight control computer, used for calculating control rate parameters and performing logical processing;

[0054] Actuator control electronics are connected to the flight control computer and serve as a backup computer for the flight control computer.

[0055] The actuator servo controller is connected to the flight control computer and the brake control electronics. The actuator servo controller is used to receive signals from the flight control computer and the actuator control electronics.

[0056] The actuator is connected to the actuator servo controller. The actuator receives signals from the actuator servo controller and performs the actions.

[0057] Operating surfaces, connected to each other, are used to control the actuators;

[0058] The digital-to-analog conversion module has multiple configurations.

[0059] The analog-to-digital converter module is connected to the actuator servo controller. The digital-to-analog converter module and the analog-to-digital converter module are used to convert digital signals to analog signals and output them.

[0060] The frequency response analyzer is connected to the digital-to-analog converter module and the analog-to-digital converter module. The frequency response analyzer performs stability margin analysis on digital signals.

[0061] Integrated circuit boards are used for modular integration and installation of actuator servo controllers, digital-to-analog converter modules, and analog-to-digital converter modules.

[0062] As one implementation method, the frequency response analyzer integrates an AI-based stability margin assessment module. This module uses machine learning algorithms to intelligently assess and predict the system's stability margin, providing suggestions for optimizing control parameters. By collecting the system's frequency domain response data and utilizing machine learning algorithms such as classification and regression, the module establishes a mapping model between stability margin and influencing factors (such as gain margin, phase margin, and bandwidth). During testing, the assessment module analyzes the collected frequency response data in real time, predicting the system's stability margin level. If insufficient stability margin or a declining trend is detected, it issues an early warning and diagnoses the cause, allowing engineers to address the issue promptly. Simultaneously, the assessment module can also use optimization algorithms to find the optimal values ​​of control parameters to improve the stability margin, providing engineers with optimization suggestions.

[0063] By mounting the digital-to-analog converter (DAC) and analog-to-digital converter (ADC) modules along with the actuator servo controller on an integrated circuit board, this integration reduces electromagnetic interference to digital signals during transmission, thereby improving signal accuracy and reliability. Integrating the DAC and ADC modules with the actuator servo controller also reduces the overall system size and weight, making it suitable for space- and weight-sensitive aerospace applications. Furthermore, the internal integration reduces the number of independent components requiring management, simplifying design, installation, and maintenance. The number of cables and connectors required in the system is also reduced, and the fewer connections and external interfaces decrease, reducing the potential for failures at physical connections and thus improving overall system reliability.

[0064] As one implementation method, integrated circuit boards employ electromagnetic interference (EMI) and radiation hardening designs to improve their reliability in harsh environments. During design and manufacturing, various measures are used to enhance their interference immunity and environmental adaptability. EMI immunity design includes rational wiring layout, shielding sensitive components, and filtering power supply noise to ensure the circuit is unaffected by external electromagnetic fields. Radiation hardening utilizes radiation-resistant components, redundant circuit design, and reinforced shielding enclosures to enable the circuit to withstand a certain dose of radiation without damage. Simultaneously, moisture-proof, salt spray-proof, and shock-proof measures are considered to ensure the integrated circuit board can adapt to harsh environments such as high humidity, salt spray, and vibration. If necessary, a conformal coating can be applied to the integrated circuit board to further improve reliability.

[0065] The actuator control electronics serves as a backup computer for the flight control computer. The actuator servo controller interprets digital signals provided by the upstream flight control computer or actuator control electronics. The actuator servo controller processes and converts specified control command signals and excitation signals by adjusting its internal logic. First, the actuator servo controller receives digital control command signals from the flight control computer; these signals may be set values ​​for target values ​​such as position, velocity, or torque. The internal logic circuitry of the servo controller decodes these signals, deciphering the specific control objective. The actuator servo controller typically obtains feedback signals from the actuator or other sensors, such as current position, velocity, or torque. These feedback signals are compared with the control command signals to generate error signals. Based on control theory (such as PID control and fuzzy control), the control logic within the actuator servo controller calculates the error signals and generates corresponding control output signals based on the magnitude, direction, and timing characteristics of the error. These control output signals are used to adjust the actuator's motion state to minimize errors and achieve precise control objectives. If both the control command signals and the internal logic operations of the servo controller are performed digitally, the servo controller needs to convert these digital signals into analog signals to drive the actuator. This is the function of the digital-to-analog converter (DAC). The DAC converts the processed digital control signal into an analog voltage or current signal. The excitation signal generated by the servo controller typically needs to be amplified before it can drive the actual actuator (such as a motor, hydraulic cylinder, or pneumatic cylinder). The power amplifier is designed to ensure that the output signal has sufficient voltage and current to meet the actuator's power requirements. The servo controller may also modulate the excitation signal to suit the specific needs of the actuator. For example, pulse width modulation (PWM) technology is often used to control the speed and position of a motor. Furthermore, filters are used to remove noise or unwanted frequency components from the signal, ensuring the stability and accuracy of the output signal. After internal logic processing and conversion, the excitation signal is finally transmitted to the actuator through the servo controller's output. The actuator performs corresponding actions based on this signal, such as movement, rotation, or force generation. While driving the actuator, the servo controller continuously monitors the feedback signal and constantly adjusts the output signal to achieve precise closed-loop control. This real-time monitoring and adjustment ensures the actuator's motion accuracy and response speed.

[0066] As one implementation method, backup units are installed in the flight control computer and actuator servo controllers. When the main controller fails, the system automatically switches to the backup unit to continue operation. Key components such as the flight control computer and actuator servo controllers employ dual-machine redundancy or multi-machine redundancy design, meaning one or more identical backup units are set up to operate synchronously and synchronize data with the main controller. The system monitors the main controller's operating status in real time, and immediately switches control to the backup unit upon detecting a main controller failure, ensuring continuous system availability. The backup unit and main controller use a hot backup method, allowing switching to be completed within milliseconds. A voting mechanism can also be employed, with multiple controllers operating simultaneously, and the final control command determined by majority vote, further improving system reliability and ensuring stable and continuous system operation.

[0067] As one implementation method, a monitoring module is installed between the flight control computer and the actuator control electronics. This module monitors the communication status and data transmission accuracy between the two systems in real time, issuing warning signals upon detecting anomalies to notify personnel for timely handling. The monitoring module collects and analyzes communication data between the flight control computer and the actuator control electronics to assess the quality of the communication link and the integrity and accuracy of the data in real time. When abnormalities such as communication interruptions, data errors, or excessive delays are detected, the monitoring module immediately issues a warning, prompting relevant personnel to check and handle the situation, preventing the abnormal conditions from continuously affecting system performance and safety, and ensuring the system can operate stably and continuously.

[0068] As one implementation method, the actuator servo controller is equipped with an adaptive control module. The adaptive control module automatically adjusts the control parameters and optimizes the control performance according to the actual working conditions of the actuator and the system requirements. The adaptive control module adopts an adaptive control algorithm, which estimates the dynamic characteristics of the actuator and external disturbances in real time based on the actual position, speed, acceleration, load and other state feedback signals of the actuator. It automatically adjusts the gain parameters and compensation parameters of the controller, so that the controller can adapt to the changes in the actuator characteristics, suppress the influence of external disturbances, thereby improving the dynamic response performance and control accuracy of the actuator, and ensuring that the optimal control effect can be achieved under different working conditions.

[0069] One set of digital-to-analog conversion modules is connected to the flight control computer's primary brake control electronics, while the other set of digital-to-analog conversion modules is connected to the actuator servo controller.

[0070] The actuator servo controller is used to determine whether control commands have been tampered with during transmission from the flight control computer to the actuator servo controller. The actuator servo controller uses a data verification algorithm for this determination. In flight control systems, the data verification algorithm used to verify whether commands have been tampered with is typically a checksum algorithm or a cryptographic hash algorithm. These algorithms ensure that the integrity and authenticity of data are not compromised during data transmission. Specifically, they can be the following algorithms:

[0071] Cyclic Redundancy Check: Cyclic Redundancy Check is a data verification algorithm widely used in communication systems. It verifies the integrity of data by generating a check code. In flight control systems, cyclic redundancy check is often used to detect whether commands have been erroneous or tampered with during transmission.

[0072] Message digest algorithms: These hash functions convert input data into a fixed-length string (often called a digest or hash value). When sending a command, the flight control computer calculates the hash value of the command and appends it to the command. Upon receiving the command, the receiver (actuator servo controller) recalculates the hash value of the command and compares it with the received hash value. If the two hash values ​​match, it means the data has not been tampered with.

[0073] HMAC (Hash Message Authentication Code with Key): This method adds a key to a regular hash algorithm to further enhance the security of data verification. Only the communicating parties with the correct key can generate or verify the correct HMAC value, thus checking not only data integrity but also data authenticity.

[0074] The choice of these algorithms typically depends on the specific requirements of the system, including security requirements, computational resource constraints, and real-time requirements. In flight control systems, ensuring data integrity and tamper resistance is crucial; therefore, highly secure verification methods are usually chosen.

[0075] The actuator control electronics (ECU) is used to superimpose control command signals and monitor communication between the flight control computer and the actuator servo controller. The ECU receives control command signals from the flight control computer and can superimpose additional correction signals as needed. These correction signals may originate from various sources, such as redundant systems, additional sensor data, or manual adjustments via external input. This superposition process allows the ECU to consider additional influencing factors or redundant commands while executing control commands, improving system safety and reliability. After signal superposition, the ECU may modulate or convert the signals to suit the needs of the actuator servo controller. For example, the superimposed signal may need to be filtered, amplified, or converted from analog to digital to ensure signal accuracy and quality. The ECU continuously monitors control signals from the flight control computer and feedback signals from the actuator servo controller. By monitoring the timing, amplitude, and frequency characteristics of the signals, the ECU can detect potential communication failures or data anomalies. For example, actuator control electronics can detect signal loss, delays, and incorrect coding, and promptly issue alarms or take corrective actions. Actuator control electronics typically verify signals according to predetermined communication protocols to ensure that data has not been tampered with or corrupted during transmission. This verification usually includes cyclic redundancy check, checksum, and hash value comparison to ensure the integrity and correctness of command and feedback signals. In many flight control systems, actuator control electronics are also responsible for managing and monitoring redundant communication channels. By comparing signals from multiple channels, actuator control electronics can determine if a channel fault exists and switch to a backup channel if necessary to ensure communication continuity. The communication monitoring function of actuator control electronics also includes fault detection capabilities, enabling the identification of abnormal conditions in the communication link, such as noise interference, signal loss, or spoofed signals. Once a fault is detected, actuator control electronics will take immediate action, which may include issuing alarms, switching to redundant systems, or activating preset emergency procedures. Actuator control electronics typically have self-testing and diagnostic functions, allowing them to perform health checks on themselves and the communication link during system startup or operation. Self-test results can help the system identify potential faults and whether maintenance or adjustments are needed. When communication monitoring detects a serious fault, the actuator control electronics may proactively execute emergency response procedures. For example, upon detecting the loss of critical signals or severe interference, the actuator control electronics can trigger the system to enter a safe mode or activate manual control to prevent accidents.

[0076] As one implementation method, the test system features real-time simulation capabilities. By connecting to a digital twin system, it enables real-time monitoring and predictive maintenance of the flight control system under test. The test system and the digital twin model of the flight control system are synchronized in real time, with the twin model's status updated in real-time using sensor data. The test system uses the twin model to perform real-time simulation of the flight control system, predicting its future performance trends and potential faults. When certain key parameters (such as stability margin) are detected to be approaching threshold values ​​or showing a downward trend, the test system issues an early warning, prompting maintenance personnel to perform checks and maintenance in advance to avoid faults. Simultaneously, the test system can intelligently generate test cases using simulation results, expanding the test coverage, optimizing the test process, and shortening the test cycle.

[0077] This invention also provides a stability margin testing method for a distributed fly-by-wire flight control system, comprising the following steps: the actuator control electronics transmits instructions from the flight control computer to the actuator servo controller; the actuator servo controller uses a data verification algorithm to confirm whether the control instructions have been tampered with during transmission from the flight control computer to the actuator servo controller; the actuator servo controller superimposes the excitation signal with the flight instructions and transmits the superimposed instructions to the actuator; simultaneously, the instructions are returned to the digital-to-analog converter module, which converts the digital signal into an analog signal and transmits it to the frequency response analyzer; the frequency response analyzer calculates the stability margin; then, the frequency response analyzer transmits the excitation signal to the actuator servo controller through the analog-to-digital converter module, and finally injects it into the actuator.

[0078] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A stability margin test system for a distributed fly-by-wire flight control system, characterized by, include: A flight control computer, which is used to perform control rate parameter calculations and logic processing; Actuator control electronics, which are connected to the flight control computer; An actuator servo controller is connected to a flight control computer and actuator control electronics. The actuator servo controller is used to receive signals from the flight control computer and actuator control electronics. An actuator is connected to an actuator servo controller. The actuator receives signals from the actuator servo controller and executes them. The actuator servo controller processes and converts specified control command signals and excitation signals by adjusting its internal logic. The actuator servo controller is used to control command superimposed signals and can monitor the communication between the flight control computer and the actuator servo controller. An operating surface, which is connected to the actuator, is used to control the actuator; The digital-to-analog conversion module is provided in multiple sets. One set of the digital-to-analog conversion module is connected to the flight control computer and the actuator control electronics, and another set of the digital-to-analog conversion module is connected to the actuator servo controller. An analog-to-digital converter module is connected to an actuator servo controller. The digital-to-analog converter module and the analog-to-digital converter module are used to convert digital signals to analog signals and output them. A frequency response analyzer, connected to a digital-to-analog converter and an analog-to-digital converter, performs stability margin analysis on digital signals. The stability margin testing method for the distributed fly-by-wire flight control system includes the following steps: the actuator control electronics transmits control commands from the flight control computer to the actuator servo controller. The actuator servo controller uses a data verification algorithm to confirm whether the control commands have been tampered with during transmission from the flight control computer to the actuator servo controller. The commands are then converted into analog signals by a digital-to-analog converter and transmitted to the frequency response analyzer. The excitation signal is then converted into a digital signal by an analog-to-digital converter. The frequency response analyzer transmits the digital signal to the actuator servo controller. The actuator servo controller superimposes the excitation signal with the digital control command and transmits the superimposed signal to the actuator. Simultaneously, the signal returns to the digital-to-analog converter, which converts the digital signal back into an analog signal and transmits it to the frequency response analyzer. The frequency response analyzer then calculates the stability margin.

2. The system for testing stability margin of a FBW flight control system according to claim 1, wherein, Also includes: An integrated circuit board is used for modular integration and installation of an actuator servo controller, a digital-to-analog converter module, and an analog-to-digital converter module.

3. A stability margin testing system for a fly-by-wire flight control system as defined in claim 2, wherein The actuator control electronics are a backup computer for the flight control computer.

4. The system for testing stability margin of a FBW flight control system according to claim 2, wherein, The actuator servo controller is used to understand digital signals provided by the upstream flight control computer or actuator control electronics.

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