A parachute control method suitable for the first test flight experiment of an unmanned aerial vehicle.

Abstract

This invention relates to a parachute control method suitable for the first test flight experiment of an unmanned aerial vehicle (UAV), comprising the following steps: S101. Initialization of test flight parameters; S102. Dynamic threshold adaptive calibration; S103. Extreme attitude recognition and ejection direction adjustment; S104. Staged parachute triggering and attitude balance control; S105. Export of test flight data. This invention solves the problems of fixed trigger thresholds, parachute opening failures in extreme attitudes, poor adaptability, and lack of data linkage in existing technologies, improving the safety of the first test flight of an UAV, reducing test flight risks and R&D costs, and simultaneously enabling complete traceability of test flight data, providing reliable support for the optimization of test flight parameters.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) flight test protection technology, specifically to a parachute control method suitable for the first flight test of UAVs, and is particularly suitable for the safety protection control of the first flight test of various small civilian and scientific research UAVs weighing 1-5kg. Background Technology

[0002] The first test flight of a drone is a crucial step in the drone development process. Its core purpose is to verify the drone's flight performance, structural reliability, and control stability. However, the first test flight has significant unique characteristics: flight parameters have not been actually calibrated, which can easily lead to drastic parameter fluctuations and attitude instability; the size, weight, and center of gravity of the prototype aircraft vary greatly, making it difficult to adapt to universality; and the completeness of the test flight data directly affects fault analysis and parameter optimization, which is one of the core requirements of the first test flight.

[0003] Existing UAV parachute control methods are primarily designed for conventional flight or operational scenarios of mature UAVs. Their core logic is "passive triggering of parachute descent after UAV loss of control," which fails to adapt to the unique characteristics of first-time test flights and suffers from the following fatal flaws: First, the trigger threshold is fixed, based on the stable flight parameters of mature UAVs, failing to consider the unknown and highly volatile parameters of first-time test flights. This easily leads to false triggers or missed triggers, severely impacting test flight effectiveness and safety. Second, there is a lack of extreme attitude adaptation control. When the UAV experiences extreme attitudes such as rolling, inverted hanging, or rapid dives during its first test flight, no ejection direction adjustment steps are provided, resulting in parachute entanglement and deployment failure, failing to provide effective protection. Third, adaptability is poor. No targeted weight adaptation control steps are provided, making it unsuitable for different centers of gravity and different types of test prototypes. This can easily cause the fuselage to roll during parachute descent due to center of gravity shift, resulting in secondary damage to the prototype. Fourth, there is no test flight data linkage and storage control. It can only achieve emergency parachute descent functionality, unable to store the parachute descent process and key test flight parameters. After a test flight failure, the cause of the malfunction cannot be located, and no support can be provided for UAV parameter optimization.

[0004] A search revealed that existing UAV parachute control methods are primarily designed for routine flight or operational scenarios of mature UAVs, failing to adequately consider the unique challenges of initial test flights, such as unknown parameters, severe fluctuations, and frequent extreme attitudes. Therefore, they are difficult to directly adapt to initial test flight scenarios. This invention addresses these issues by proposing a parachute control method specifically designed for initial UAV test flights. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing UAV parachute control methods that cannot be adapted to the first test flight experiment of UAVs, and to provide a parachute control method suitable for the first test flight experiment of UAVs. This method solves the problems of fixed trigger threshold, parachute opening failure in extreme attitudes, poor adaptability, and lack of data linkage in the existing technology, improves the safety of the first test flight of UAVs, reduces test flight risks and R&D costs, and enables complete traceability of test flight data, providing reliable support for the optimization of test flight parameters.

[0006] The present invention is achieved through the following technical solution.

[0007] This invention provides a parachute control method suitable for the first test flight experiment of an unmanned aerial vehicle (UAV), based on adaptation. The small unmanned aerial vehicle's parachute landing device is activated. This device includes a ground control module, an attitude perception module, a parameter acquisition module, an embedded control module, a tiered parachute landing mechanism module, an ejection drive module, a weight adaptation module, a data storage module, a self-test module, and a wireless communication module. These modules work together to achieve adaptive parachute landing control and data traceability during the initial test flight. The specific control steps are as follows:

[0008] S101. Flight Test Parameter Initialization: Before the flight test, staff input the design parameters of the test drone prototype through the ground control module (computer or mobile APP). These design parameters include the drone's weight, center of gravity position, and preset flight parameter range. The preset flight parameter range is set according to the prototype's design performance and typically includes a preset flight speed. Preset attitude angle To ensure the initialization parameters match the prototype's characteristics, the embedded control module receives the design parameters and completes the initialization configuration. Simultaneously, it sends control commands to the counterweight adaptation module, driving the counterweight to move to an initial position matching the prototype's center of gravity, preventing initial attitude imbalance of the UAV. Subsequently, the self-test module is activated to perform self-tests on each module. These self-tests include signal transmission detection, ejection drive module response detection, and counterweight adaptation module adjustment accuracy detection, ensuring all modules function correctly and laying the foundation for subsequent parachute control. The self-test module is not an independent module but a functional module integrated into the embedded control module; the self-test object is all core modules of the parachute device. After completion, the data storage module is activated to collect and store key data from the entire flight test process, including data before parachute triggering. The moment of triggering, during parachute opening, and before landing. The flight parameters, as well as the cause of the parachute landing, ejection time, parachute deployment time, and landing speed.

[0009] S102. Dynamic Threshold Adaptive Calibration: During the first test flight of the UAV, the parameter acquisition module... The system collects the drone's flight parameters in real time at a specific frequency. These parameters include attitude angles (roll, pitch, yaw), flight speed, battery voltage, and motor speed. The attitude angle measurement accuracy is [not specified]. Flight speed collection range Battery voltage acquisition range Motor speed acquisition range This ensures the accuracy and comprehensiveness of the collected parameters. The parameter acquisition module synchronously transmits the flight parameters to the embedded control module and the data storage module. The embedded control module incorporates a PID adaptive adjustment algorithm to dynamically adjust the parachute trigger threshold based on real-time parameter fluctuations during the test flight, breaking the limitations of existing fixed thresholds; the core calibration benchmark is the pre-test flight... The average value of the collected flight parameters (denoted as ) This baseline is only applicable at the initial stage of flight testing (after the drone has just taken off and completed initialization before entering stable flight). The calculation is performed once within the current step, and subsequent control flows returning to this step will not recalculate it. Based solely on what has been determined It dynamically updates the trigger threshold based on real-time parameter fluctuations, avoiding logical conflicts caused by repeated calculations of the baseline value during the loop. Its core calibration formula, parameter deviation calculation, and parameter descriptions are as follows:

[0010] 1. Formula for calculating real-time parameter deviation:

[0011] 2. Core formula for PID dynamic threshold calibration:

[0012]

[0013] The meaning and value range of each parameter in the above formula strictly conform to the control logic of this invention, as detailed below:

[0014] : It continuously collects the deviation values ​​of parameters from the benchmark values ​​in real time, reflecting the degree of fluctuation of the current flight parameters;

[0015] : Flight parameters (attitude angle, flight speed, battery voltage, motor speed) are collected in real time.

[0016] Before the test flight The average values ​​of the corresponding flight parameters collected are used as the basis for dynamic calibration, which is consistent with the stable parameter state in the early stage of the first test flight.

[0017] The dynamically calibrated parachute trigger threshold is the final reference value used to determine whether a parachute drop should be triggered.

[0018] Threshold fluctuation ratio (default value) It can be flexibly adjusted according to the characteristics of the test prototype through the ground control module to adapt to the parameter fluctuation range of different prototypes;

[0019] PID algorithm proportional coefficient (value) This is used to quickly respond to deviations between real-time parameters and benchmark values;

[0020] PID algorithm integral coefficients (values) This is used to eliminate calibration errors caused by accumulated deviations;

[0021] PID algorithm derivative coefficients (values) This is used to suppress frequent threshold fluctuations and improve calibration stability;

[0022] The integral term of the deviation value reflects the cumulative effect of the deviation, avoiding calibration inaccuracies caused by long-term small deviations; among which... for Once the calculation is complete, the integration interval begins from the baseline calculation to avoid the cumulative impact of sharp fluctuations during the initial takeoff phase. Additionally, the integration term can be reset each time a threshold update is triggered to prevent integration saturation.

[0023] The differential term of the deviation value reflects the rate of change of the deviation, allowing for early prediction of parameter fluctuation trends and avoiding false triggering.

[0024] Specific test flight scenario example: If before the test flight The average flight speed is (Right now ), preset floating ratio for , Real-time flight speed Then first calculate using the deviation formula. For ease of understanding, this example temporarily ignores the cumulative effect of the integral and derivative terms (assuming the deviation is stable over a short period, and the contributions of the integral and derivative terms are approximately zero). Substituting these values ​​into the PID calibration formula, we then set... ,formula: The dynamic trigger threshold is calculated. ,at this time Exceeding The range immediately triggers a parachute warning; in practical applications, the integral and derivative terms are finely adjusted to the threshold based on the accumulation and rate of change of the deviation; this is a simplified example. If... If the time parameter does not exceed the threshold, the process returns to this step and only re-collects data. ,calculate ,renew No recalculation This is designed to accommodate the volatile parameters during the initial flight test, while avoiding logical conflicts. The calibrated parameters will be... As a criterion for determining whether a parachute jump has been triggered, the calibration data is simultaneously synchronized to the data storage module for archiving.

[0025] S103. Extreme Attitude Recognition and Launch Direction Adjustment: The attitude perception module uses a high-precision MEMS sensor to collect the UAV's attitude data (roll angle) in real time. Pitch angle The data is synchronously transmitted to the embedded control module and the data storage module. The embedded control module performs real-time analysis of the collected attitude data using the attitude deviation formula to determine whether the UAV is in an extreme attitude. The core judgment formula and logic are as follows:

[0026] 1. Formula for calculating roll angle deviation:

[0027] 2. Pitch angle deviation calculation formula:

[0028] The meanings of the parameters in the formula are as follows:

[0029] : The constant roll angle deviation reflects the degree of tumbling of the drone;

[0030] : Roll angle in real time;

[0031] Initial roll angle of the drone (during normal flight) );

[0032] : The constant pitch angle deviation reflects the degree to which the drone is upside down;

[0033] : Real-time pitch angle;

[0034] Initial pitch angle of the UAV (0° during normal flight).

[0035] Extreme posture judgment criteria: when (roll), (Upside down), or descent speed Exceeding a preset threshold (this preset threshold is an extremely high value, such as 8-15 m / s, used to identify extreme conditions of rapid dive crashes, distinct from the dynamic speed threshold used in S102 to determine normal flight anomalies; the threshold can be adjusted via the ground control module according to the UAV's weight and aerodynamic characteristics, with a recommended range of...) ), or the rate of change of the rate of descent Exceeding the preset range. These extreme attitudes are dangerous conditions that are very likely to occur during the first test flight, and are also a core pain point that existing parachute control methods cannot address. If the embedded control module determines that the UAV is in an extreme attitude, it immediately sends a control command to the ejection drive module to control the micro servo motor to drive the ejection assembly to rotate. The rotation response time is... Quickly adjust the launch direction to reduce the deviation between the launch direction and the direction of gravity. To ensure the correct deployment direction of the canopy and prevent canopy entanglement and opening failure due to incorrect ejection direction, the embedded control module does not perform ejection direction adjustment actions unless the situation is in an extreme posture. Instead, it directly proceeds to step S104, ensuring efficient process flow without unnecessary operations. The posture judgment result, ejection direction adjustment command, and execution status are synchronously transmitted to the data storage module for archiving.

[0036] S104. Staged Parachute Drop Triggering and Attitude Balance Control: The embedded control module compares the flight parameters acquired by the parameter acquisition module with the trigger threshold calibrated in step S102 in real time. The core control logic is as follows: If any flight parameter exceeds the trigger threshold, or a manual parachute command is received from the ground control module (which can be manually triggered when staff detect an anomaly), the graded parachute mechanism module and subsequent workflow are immediately triggered to ensure that the parachute descent is executed quickly and orderly; if all flight parameters do not exceed the trigger threshold and no manual parachute command is received from the ground control module, the control flow returns to step S102 and continues based on the baseline determined in step S102 ( The system collects flight parameters in real time, calculates parameter deviations, and updates dynamic trigger thresholds. Steps S102 to S104 are repeated to achieve cyclical monitoring of the entire flight process, avoiding both process interruptions and redundant calculations. This leads to a logical conflict. Simultaneously, the attitude balance is controlled via a formula for fine-tuning the position of the counterweights, and buffer protection is triggered via a formula for triggering the landing speed buffer. The core formulas and control logic are as follows:

[0037] 1. Formula for fine-tuning the position of the counterweight:

[0038] 2. Landing speed buffer trigger formula:

[0039] The meanings of the parameters in the formula are as follows:

[0040] : The position of the counterweight at all times;

[0041] Initial position of the counterweight (matching the center of gravity of the prototype);

[0042] : To dynamically adjust the coefficient, in relation to the weight of the drone. Moment of inertia The relevant parameters can be pre-calculated using structural parameters input from the ground control module, or optimized in real-time using an adaptive algorithm during the initial flight test phase. Furthermore, it is clarified that this formula is applicable to situations with small center of gravity offsets and attitude tilt angle deviations. For scenarios within the specified range, more complex control strategies (such as PID control) are employed when the range is exceeded.

[0043] : Constant-time drone attitude tilt angle deviation ( , This represents the real-time attitude tilt angle. (Ideal tilt angle 0°).

[0044] : Real-time landing speed of drones;

[0045] Landing speed buffer trigger threshold (fixed to) ).

[0046] Details of the tiered parachute descent mechanism module: The first stage ejection is driven by a compression spring with an elastic coefficient of [missing information]. ejection stroke Parachute canopy detachment time This ensures the parachute canopy detaches quickly, creating space for the parachute to deploy; the second-stage ejection is driven by a miniature electromagnetic triggering device, with a response time of [time missing]. Release the parachute lines to quickly unfold the canopy; the time for the canopy to fully unfold is... This enables the drone to decelerate rapidly. During the canopy deployment process, the weight adaptation module adjusts the weight based on the data collected by the attitude sensing module. The real-time position of the counterweight is calculated using the formula for fine-tuning the counterweight position. Drive a micro stepper motor to fine-tune the counterweight, and adjust the counterweight with high precision. Adjust response time ,make sure This prevents the aircraft from rolling and sustaining secondary damage due to a shift in the center of gravity. Furthermore, once the canopy has deployed, the parameter acquisition module collects the landing speed in real time. If the buffer triggering formula is satisfied The embedded control module immediately controls the ejection drive module to release the buffer rope, further reducing the impact force upon landing and preventing damage to the test prototype. During this process, core data such as the parachute trigger status, staged ejection time, attitude fine-tuning data, and landing speed are synchronously transmitted to the data storage module for archiving.

[0047] S105. Flight Test Data Export: After the flight test parameter initialization unit starts, the data storage module synchronously stores the entire flight test process data. The data storage module adopts... SD card capacity, read / write speed The data is stored in CSV format and can be directly opened and analyzed using Excel. The data storage module employs a hierarchical storage strategy, dividing the data into "ordinary data" and "critical data." The critical data covers all core data across the five major units, including data prior to the parachute trigger. At the moment of triggering, during parachute opening, 10 seconds after parachute triggering, and before landing. The flight parameters, and the reasons for the parachute landing (including but not limited to data within 5 seconds before and after the moment when the parameters exceeded the threshold), ejection time (accuracy) ), umbrella unfolding time (accuracy) ), landing speed (accuracy) Data such as the 5 seconds before and after the occurrence of extreme attitudes are crucial for fault analysis and parameter optimization during the initial flight test. When storage space is insufficient, ordinary data is overwritten first, while critical data is allocated to a separate storage area or protected with the highest priority to ensure it is not overwritten until it is manually exported or storage space is completely exhausted due to excessive critical data (this situation rarely occurs). After the flight test, the data storage module exports the stored critical data to the ground control module via the wireless communication module. The export speed is [not specified in the original text]. The ground control module displays key data for staff analysis. By analyzing this data, staff can quickly pinpoint the cause of the drone's loss of control, optimize the drone's design parameters, and shorten the development cycle.

[0048] Compared with the prior art, the advantages of the present invention are:

[0049] 1. Adaptive adjustment of trigger threshold to accommodate parameter fluctuations during the first test flight: This invention employs a PID adaptive adjustment algorithm, combining real-time parameter deviation formulas and PID calibration formulas, to dynamically adjust the parachute landing trigger threshold and establish a clear baseline. It is calculated only once during the initial test flight, avoiding logical conflicts during the loop process; unlike the fixed threshold design of existing technologies, it effectively avoids the problem of false triggering or missed triggering caused by fluctuations in parameters during the first test flight. The trigger response speed is fast and the accuracy is high, which significantly improves the safety of the first test flight.

[0050] 2. Strong adaptability to extreme attitudes, solving the pain point of parachute opening failure: This invention accurately judges the extreme attitudes that are likely to occur during the first test flight by using roll angle and pitch angle deviation formulas. Combined with the ejection direction adjustment logic, it ensures that the parachute deployment direction is correct under extreme attitudes, which solves the defect of existing parachute control methods that fail to open under extreme attitudes and further improves the reliability of protection.

[0051] 3. Adaptable to various types of test flight prototypes, with good versatility: This invention uses the test flight parameter initialization and counterweight fine-tuning position formula to adapt to various small test flight drones weighing 1-5kg without the need to modify the test flight prototype. By adjusting the initialization parameters and formula correlation coefficients, it can adapt to the differences in the center of gravity of different prototypes, avoid secondary damage, and has strong versatility, thus reducing test flight costs.

[0052] 4. Integrated data linkage storage enables flight test data traceability: This invention sets up a dedicated data linkage storage and export step to synchronously store key data throughout the entire flight test process, providing direct support for fault analysis and parameter optimization during the first flight test, filling the gap in existing parachute control methods that lack flight test data linkage, and shortening the research and development cycle.

[0053] 5. Rigorous control logic and strong feasibility: This invention clarifies the correlation between various parameters through multiple sets of formulas that fit the control steps, while optimizing the process logic and clarifying... The calculation is performed only once during the initial test flight and is not repeated in subsequent cycles, thus resolving process conflict issues. The control steps are logically clear and smoothly connected. The formulas and parameter settings are all within the range achievable by existing mature technologies, requiring no new research and development. It can be quickly integrated with existing parachute devices for practical application, demonstrating strong practicality and market potential. Attached Figure Description

[0054] Figure 1 : Overall flowchart of the parachute control method of the present invention;

[0055] Figure 2 The overall flowchart of the parachute control method of the present invention without triggering the tiered parachute descent mechanism is shown below.

[0056] Figure 3 : Schematic diagram of the application architecture of the parachute control system provided in this embodiment of the invention;

[0057] Figure 4 The following is a schematic diagram of the application architecture of the parachute control system provided in this embodiment of the invention without triggering the tiered parachute descent mechanism.

[0058] Figure 5 : Flowchart of the principle of the test flight parameter initialization unit of this invention;

[0059] Figure 6: Flowchart of the principle of the dynamic threshold adaptive calibration unit of the present invention;

[0060] Figure 7 : Flowchart of the principle of the extreme attitude recognition and ejection direction adjustment unit of the present invention;

[0061] Figure 8 : Flowchart of the principle of the graded parachute triggering and attitude balance control unit of this invention;

[0062] Figure 9 : Flowchart of the principle of the flight test data export unit of this invention;

[0063] Figure 10 : A structural block diagram of the test flight parameter initialization unit 101 of the present invention;

[0064] Figure 11 : A structural block diagram of the dynamic threshold adaptive calibration unit 102 of the present invention;

[0065] Figure 12 : Structural block diagram of the extreme attitude recognition and ejection direction adjustment unit 103 of the present invention;

[0066] Figure 13 : Structural block diagram of the graded parachute landing triggering and attitude balance control unit 104 of the present invention;

[0067] Figure 14 : Structural block diagram of the flight test data export unit 105 of the present invention. Detailed Implementation

[0068] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0069] Example: A parachute control method suitable for the first test flight experiment of an unmanned aerial vehicle (UAV)

[0070] The parachute control method in this embodiment is based on a parachute device adapted to a 3kg multi-rotor UAV. The parachute device includes an MPU6050 attitude sensing module, an ACS712 parameter acquisition module, an STM32F103 embedded control module, an SG90 ejection drive module, a 28BYJ48 counterweight adaptation module, and a 32GB SD card data storage module (the above models are only examples; in actual applications, equivalent modules can be used). The specific control steps are as follows:

[0071] S101. Flight Test Parameter Initialization: Input the design parameters of the 3kg multi-rotor UAV prototype through the ground control module, including weight 3kg and center of gravity located slightly forward of the fuselage center. (i.e., the initial position of the counterweight) The fuselage center is slightly forward ), preset flight parameter range (flight speed) Attitude angle The STM32F103 embedded control module receives parameters and completes initialization, while simultaneously controlling the 28BYJ48 counterweight adapter module driver. The counterweight was moved to Upon arrival, each module initiates a self-test to confirm normal operation. The 32GB SD card data storage module simultaneously starts, collecting and storing critical data, including data prior to parachute triggering. Before landing Flight parameters (including each time) , , , , ), and the reasons for the parachute landing (flight speed exceeding the threshold), ejection time, etc. Umbrella deployment time landing speed .

[0072] S102. Dynamic Threshold Adaptive Calibration: After the UAV takes off, it enters the first 5 seconds of test flight. The parameter acquisition module collects flight parameters at a frequency of 100Hz during these 5 seconds and calculates the average flight speed. (Right now ),Should This calculation is performed only once during this phase and will not be repeated subsequently; thereafter, the parameter acquisition module continues to... Real-time acquisition of flight parameters (attitude angle, flight speed, battery voltage) via frequency Left and right, motor speed (Left and right); The embedded control module incorporates a PID adaptive adjustment algorithm and sets parameters. , , Preset threshold fluctuation ratio .when Real-time flight speed First, calculate using the deviation formula. Then substitute it into the PID calibration formula The dynamic trigger threshold is calculated. ,at this time Exceeding The area triggered a parachute warning; if subsequent... If the time parameter does not exceed the threshold, the process returns to this step and only re-collects data. ,calculate ,renew No recalculation .

[0073] S103. Extreme Attitude Recognition and Ejection Direction Adjustment: The MPU6050 attitude perception module collects UAV attitude data in real time. When the UAV rolls... Real-time roll angle Calculated using the roll angle deviation formula The system is identified as exhibiting an extreme posture; the embedded control module immediately sends control commands to the SG90 catapult drive module, controlling the micro servo motors to drive the catapult assembly to rotate. The internal adjustment of the ejection direction is 3° away from the direction of gravity to ensure the correct ejection direction; if the attitude returns to normal afterward, the direction adjustment action will not be performed when the process enters S104.

[0074] S104. Staged Parachute Descent Triggering and Attitude Balance Control: When the UAV's flight speed reaches... Exceeding the dynamic trigger threshold ( When this occurs, the embedded control module immediately triggers the tiered parachute descent mechanism: the first stage ejection is achieved by compressing the spring (elastic coefficient...). The parachute canopy detaches. The parachute canopy detaches internally; the second-stage ejection releases the parachute lines via a miniature electromagnetic trigger device. Inner finished umbrella surface (diameter) Fully deployed. Real-time attitude tilt angle after the umbrella is deployed. ,calculate At this point, based on the drone weight entered in step S101... and the preset estimated value of rotational inertia The dynamic fine-tuning coefficients for the current attitude are calculated using pre-defined mapping relationships (such as lookup tables or simplified formulas) within the module. (This value is for illustrative purposes only; in actual applications, it will be dynamically determined based on the drone model and the degree of center of gravity shift.) Substitute this value into the formula for fine-tuning the position of the counterweight. Drive the counterweight to move to Location, ensure When the landing speed is detected Satisfying the buffer triggering formula Control the release of the buffer rope to reduce the impact force upon landing; if the parameters in this step do not exceed the threshold and there is no manual instruction, the process returns to S102 and continues to cycle and monitor.

[0075] S105. Flight Test Data Linkage Storage and Export: After the flight test, the data is exported to the ground control module via WiFi. The export speed is [not specified]. The data is saved in CSV format, and the ground control module displays key data for staff to analyze, for fault analysis and parameter optimization.

[0076] The parachute control method in this embodiment can effectively adapt to the scenario of the first test flight of a 3kg multi-rotor UAV, accurately trigger the parachute descent, stably control the parachute attitude, and solve the conflict problem of repeated calculation of reference values ​​in the loop process. It can achieve complete traceability of test flight data, successfully avoid UAV crashes and damage, improve test flight safety, reduce R&D costs, and can be widely applied to the first test flight experiments of similar small UAVs.

[0077] The parachute control method of the present invention is applicable not only to the embodiments described herein. Multi-rotor drones, also compatible with Other small drones within the range (such as fixed-wing and helicopter drones) only need to have their initialization parameters (weight, center of gravity, preset parameter range) and formula correlation coefficients adjusted via the ground control module. (etc.) can achieve adaptation and has strong versatility.

[0078] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A parachute control method suitable for the first test flight experiment of an unmanned aerial vehicle (UAV), characterized in that, This parachute control method is based on adaptation. The small unmanned aerial vehicle's parachute landing device is executed. This device includes a ground control module, an attitude perception module, a parameter acquisition module, an embedded control module, a tiered parachute landing mechanism module, an ejection drive module, a weight adaptation module, a data storage module, a self-test module, and a wireless communication module. These modules work together to achieve adaptive parachute landing control and data traceability during the initial test flight. Specifically, the steps include: S101. Test Flight Parameter Initialization: Before the test flight, the staff input the design parameters of the test flight UAV prototype through the ground control terminal module. The embedded control module receives the above design parameters and completes the initialization configuration. At the same time, it sends control commands to the counterweight adaptation module to drive the counterweight block to move to the initial position that matches the center of gravity of the prototype to avoid the initial attitude imbalance of the UAV. Then the self-test module is started to perform self-tests on each module. After the self-test is completed, the data storage module is started to collect and store key data in the entire flight test process. S102. Dynamic Threshold Adaptive Calibration: During the first test flight of the UAV, the parameter acquisition module... The system collects the UAV's flight parameters in real time, including attitude angles, flight speed, battery voltage, and motor speed. The parameter acquisition module synchronously transmits the collected flight parameters to the embedded control module and data storage module. The embedded control module incorporates a PID adaptive adjustment algorithm to dynamically adjust the parachute trigger threshold based on real-time parameter fluctuations during flight testing, breaking the limitations of existing fixed thresholds. The core calibration formula and parameter deviation calculation are as follows: Real-time parameter deviation calculation formula: Core formula for PID dynamic threshold calibration: In the formula: for The deviation between the parameters and the benchmark value is collected in real time. for Flight parameters collected in real time. As the basic benchmark for dynamic calibration, This is the dynamically calibrated parachute trigger threshold. The threshold fluctuation ratio, The proportional coefficient for the PID algorithm. The integral coefficients of the PID algorithm These are the differential coefficients of the PID algorithm. The integral term of the deviation value. The differential term of the deviation value; Among them, the basic reference for dynamic calibration Before test flight The average value of the collected flight parameters, The calculation is performed only once at the initial stage of flight test launch, and is not recalculated when the control flow loops back to this step. By combining real-time parameter fluctuations with dynamic trigger threshold updates, logical conflicts caused by repeated calculation of the baseline value during the loop are avoided. S103. Extreme Attitude Recognition and Launch Direction Adjustment: The attitude perception module uses a high-precision MEMS sensor to collect the UAV's attitude data in real time, including roll angle. and pitch angle The data is synchronously transmitted to the embedded control module and the data storage module. The embedded control module performs real-time analysis of the collected attitude data using the attitude deviation formula to determine whether the UAV is in an extreme attitude. The core judgment formula and logic are as follows: Roll angle deviation calculation formula: Pitch angle deviation calculation formula: In the formula: for Roll angle deviation at all times for Roll angle in real time The initial roll angle of the drone. for Pitch angle deviation at all times for Real-time pitch angle This is the initial pitch angle of the UAV; Extreme posture judgment criteria: when , descent speed Exceeding the preset threshold or the rate of change of descent speed Exceeding the preset range; If the embedded control module determines that the drone is in an extreme attitude, it immediately sends a control command to the catapult drive module to control the micro servo motor to drive the catapult assembly to rotate. The rotation response time is... Quickly adjust the launch direction to reduce the deviation between the launch direction and the direction of gravity. Ensure the canopy unfolds in the correct direction to avoid canopy tangling or failure to open due to incorrect ejection direction; If the embedded control module determines that the drone is not in an extreme attitude, the embedded control module will not perform the ejection direction adjustment action and will directly enter step S104 to ensure efficient connection of the process without unnecessary operations. The embedded control module synchronously transmits the attitude judgment results, ejection direction adjustment commands and execution status to the data storage module for archiving. S104. Staged Parachute Drop Triggering and Attitude Balance Control: The embedded control module compares the flight parameters acquired by the parameter acquisition module with the trigger threshold calibrated in step S102 in real time. The core control logic is as follows: If any flight parameter exceeds the trigger threshold, or if a manual parachute command is received from the ground control module, the graded parachute mechanism module and subsequent workflow are immediately triggered to ensure that the parachute descent is executed quickly and in an orderly manner. If all flight parameters do not exceed the trigger threshold and no manual parachute command is received from the ground control module, the control flow returns to step S102 and continues based on the baseline determined in step S102. The system collects flight parameters in real time, calculates parameter deviations, and updates dynamic trigger thresholds. Steps S102 to S104 are repeated to achieve cyclical monitoring of the entire flight process, avoiding both process interruptions and redundant calculations. This can lead to a logic surge; simultaneously, the attitude balance is controlled by a formula for fine-tuning the position of the counterweight, and the buffer protection is triggered by a formula for buffering the landing speed. The specific formulas and control logic are as follows: Formula for fine-tuning the position of the counterweight: Landing speed buffer trigger formula: In the formula: for The position of the counterweight at all times. The initial position of the counterweight. For dynamic adjustment coefficients, for Constant deviation of the drone's attitude tilt angle for Real-time landing speed of drones Buffer the landing speed trigger threshold S105. Flight Test Data Export: After the flight test parameter initialization unit starts, the data storage module synchronously stores the entire flight test process data. The data storage module adopts a hierarchical storage strategy: the data is divided into ordinary data and key data. After the test flight, the data storage module exports the stored key data to the ground control module via the wireless communication module. The ground control module displays the key data for staff to analyze.

2. The parachute control method for the first test flight experiment of an unmanned aerial vehicle (UAV) according to claim 1, characterized in that, In step S101, the design parameters include the weight of the UAV, the position of the center of gravity, and the preset flight parameter range. The preset flight parameter range is set according to the design performance of the prototype to ensure that the initialization parameters fit the characteristics of the prototype.

3. The parachute control method for the first test flight experiment of an unmanned aerial vehicle (UAV) according to claim 1, characterized in that, In step S101, the self-test includes signal transmission detection of each module, response detection of the ejection drive module, and adjustment accuracy detection of the counterweight adaptation module, to ensure that each module works normally and lay the foundation for subsequent parachute control; the self-test module is a functional module integrated into the embedded control module.

4. The parachute control method for the first test flight experiment of an unmanned aerial vehicle (UAV) according to claim 1, characterized in that, In step S101, the key data includes flight parameters 10 seconds before the parachute is triggered, at the moment of triggering, during the parachute opening process, and 5 seconds before landing, as well as the reason for the parachute triggering, ejection time, parachute deployment time, and landing speed.

5. The parachute control method for the first test flight experiment of an unmanned aerial vehicle (UAV) according to claim 1, characterized in that, In step S102, the attitude angle measurement accuracy Flight speed collection range Battery voltage acquisition range Motor speed acquisition range This ensures that the collected parameters are accurate and comprehensive.

6. The parachute control method for the first test flight experiment of an unmanned aerial vehicle (UAV) according to claim 1, characterized in that, In step S104, the tiered parachute descent mechanism module works as follows: The first-stage ejection is driven by a compression spring with an elastic coefficient of [missing information]. ejection stroke Parachute canopy detachment time This ensures that the canopy detaches quickly, creating space for the canopy to unfold. The second-stage ejection is driven by a miniature electromagnetic triggering device, with a response time of [missing information]. Release the parachute lines to quickly unfold the canopy; the time for the canopy to fully unfold is... This enables the drone to decelerate rapidly. During the deployment of the umbrella canopy, the weight adaptation module uses data collected by the attitude sensing module. The real-time position of the counterweight is calculated using the formula for fine-tuning the counterweight position. Drive a micro stepper motor to fine-tune the counterweight, and adjust the counterweight with high precision. Adjust response time ,make sure To avoid the fuselage rolling and secondary damage caused by the shift in the center of gravity; Once the umbrella unfolds, the parameter acquisition module collects the landing speed in real time. If the buffer triggering formula is satisfied The embedded control module immediately controls the ejection drive module to release the buffer rope, further reducing the impact force upon landing and preventing damage to the test prototype. During this process, the parachute trigger status, staged ejection time, attitude fine-tuning data, and landing speed are synchronously transmitted to the data storage module for archiving.

7. The parachute control method for the first test flight experiment of an unmanned aerial vehicle (UAV) according to claim 1, characterized in that, In step S105, the key data includes the data prior to the parachute triggering. At the moment of triggering, during parachute opening, 10 seconds after parachute triggering, and before landing. The flight parameters, as well as the cause of the parachute landing, ejection time, parachute deployment time, landing speed, and data within 5 seconds before and after the occurrence of extreme attitudes; When storage space is insufficient, ordinary data is overwritten first, while critical data will be allocated to a separate storage area or protected with the highest priority to ensure that it is not overwritten until it is manually exported or the storage space is completely exhausted due to too much critical data.

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