Method and device for enhancing static stability of unmanned aerial vehicle

Abstract

The invention discloses a method and device for enhancing static stability of an unmanned aerial vehicle, and relates to the technical field of unmanned aerial vehicles. Comprising the following steps: acquiring a pitching moment and a yawing moment of a parachute unit combination of the unmanned aerial vehicle and the stability augmentation parachute, performing stability operation calculation analysis, and determining a stress area and a parachute cord length of the stability augmentation parachute based on a stability operation calculation analysis result; a hanging point of the stability augmentation umbrella is located at the central position of a longitudinal symmetry axis of the unmanned aerial vehicle; the unmanned aerial vehicle is carried to a preset height in the air, the unmanned aerial vehicle is released when the wings are unfolded, and then the stability augmentation parachute is unfolded; and after the unmanned aerial vehicle adjusts the attitude to complete diving leveling operation, the stability augmentation parachute is cut off. The problem of how to enhance the stability of the unmanned aerial vehicle without changing the aerodynamic configuration of the unmanned aerial vehicle so as to reduce the risk of accidents caused by divergence control in the flight process is solved.

Description

Technical Field

[0001] This application relates to the technical field of unmanned aerial vehicles, and particularly to a method and device for enhancing the static stability of unmanned aerial vehicles. Background Art

[0002] In the R & D process of unmanned aerial vehicles, after the overall and aerodynamic design links are completed, it is necessary to conduct a wind tunnel blowing test on the produced and processed unmanned aerial vehicles, and analyze and evaluate the handling and stability characteristics of the unmanned aerial vehicles according to the wind tunnel data. Since the production and processing generally deviate from the actual design scheme, and some unmanned aerial vehicles need to be specially designed for the aerodynamic shape due to special flight scenarios or flight stages to improve the maneuverability or flight endurance of the unmanned aerial vehicles, but the stability of the unmanned aerial vehicles will be lost. The decrease in stability poses a great challenge to the flight control of unmanned aerial vehicles and increases the flight risk. On the other hand, since the unmanned aerial vehicle has been produced and processed, the aerodynamic shape cannot be changed again, and only the means of flight control can be used to achieve the autonomous and safe flight of the unmanned aerial vehicle, but there are still great uncertainties in actual operation, and the flight risk is difficult to be effectively controlled.

[0003] Therefore, how to enhance the stability of unmanned aerial vehicles without changing the aerodynamic shape of unmanned aerial vehicles to reduce the risk of accidents caused by control divergence during flight has become an urgent problem at present. Summary of the Invention

[0004] In the embodiments of this application, by providing a method for enhancing the static stability of unmanned aerial vehicles, the problem of how to enhance the stability of unmanned aerial vehicles without changing the aerodynamic shape of unmanned aerial vehicles to reduce the risk of accidents caused by control divergence during flight is solved.

[0005] In a first aspect, the embodiments of this application provide a method for enhancing the static stability of unmanned aerial vehicles. The method includes: obtaining the pitching moment and yaw moment of the combination of the unmanned aerial vehicle and the stability augmentation parachute and performing handling and stability calculation and analysis, and determining the force-bearing area and the length of the parachute ropes of the stability augmentation parachute based on the results of the handling and stability calculation and analysis; installing the stability augmentation parachute at the tail of the unmanned aerial vehicle, and its hanging point is located at the center position of the longitudinal symmetry axis of the unmanned aerial vehicle; carrying the unmanned aerial vehicle to a preset height in the air, releasing it in the wing-unfolded attitude, and then opening the stability augmentation parachute; after the unmanned aerial vehicle adjusts its own attitude to complete the dive and leveling operation, cutting off the stability augmentation parachute.

[0006] In a possible implementation, obtaining the pitch moment and yaw moment of the combined drone and stability augmentation parachute, and performing handling and stability calculation and analysis, and determining the force area and suspension line length of the stability augmentation parachute based on the results of the handling and stability calculation and analysis, includes: superimposing the pitch moment and yaw moment of the stability augmentation parachute onto the pitch moment and yaw moment of the drone respectively to obtain the pitch moment and yaw moment of the combined drone and parachute; performing handling and stability calculation and analysis based on the pitch moment and yaw moment of the combined drone and parachute; and determining the force area and suspension line length of the stability augmentation parachute with the damping ratio and overshoot of the combined drone and parachute as the constraint conditions of the results of the handling and stability calculation and analysis.

[0007] In a possible implementation, the calculation formula for the pitch moment of the stability augmentation parachute is: ; where is the pitch moment of the stability augmentation parachute, is the drag coefficient of the stability augmentation parachute, is the force area of the stability augmentation parachute, is the distance between the parachute attachment point and the aerodynamic focus of the drone, is the angle of attack of the drone; the calculation formula for the yaw moment of the stability augmentation parachute is: ; where is the sideslip angle of the drone; where ; is the radius of the stability augmentation parachute, is a mathematical constant.

[0008] In a possible implementation, it further includes verifying whether the force area of the stability augmentation parachute meets the requirements through simulated flight based on a preset principle, and the preset principle specifically includes: after the drone completes the dive-to-level operation, the stability augmentation parachute is cut off, and the minimum speed of the drone is greater than or equal to a preset multiple of the stall speed of the drone, and at the same time the maximum speed of the drone is less than or equal to the flutter speed of the drone; where the preset multiple is greater than 1.

[0009] In a possible implementation, carrying the drone to a preset altitude in the air, releasing it in the wing-unfolded attitude, and then opening the stability augmentation parachute, includes: when the drone is in the state of folded wings, it is carried to the preset altitude by an aerial vehicle; when the drone reaches the preset altitude, the drone performs a wing-unfolding action; after the wing-unfolding action is completed, the aerial vehicle releases the drone; the drone detects the release signal and opens the stability augmentation parachute, and at this time, the body attitude is adjusted when the propeller is in a stationary state.

[0010] In a possible implementation, after the drone adjusts its own attitude to complete the dive-to-level operation, cutting off the stability augmentation parachute, includes: the drone performs the dive-to-level operation by adjusting its own attitude, gradually reducing the pitch angle, and transitioning to the horizontal flight state; when the drone completes the dive-to-level operation, the stability augmentation parachute is cut off, the propeller is turned on, and the normal flight process is executed.

[0011] In a possible implementation, the judgment criterion for the UAV to complete the dive and level-off operation is that the pitch angle of the UAV is greater than a preset angle and the duration is greater than a preset time.

[0012] In a second aspect, an embodiment of the present application provides a device for enhancing the static stability of a UAV. The device includes: a determination module, configured to obtain the pitch moment and yaw moment of the UAV and the combined body of the UAV and the stability augmentation parachute, and perform handling and stability calculation and analysis, and determine the force-bearing area and the length of the parachute ropes of the stability augmentation parachute based on the results of the handling and stability calculation and analysis; an installation module, configured to install the stability augmentation parachute at the tail of the UAV, and its hanging point is located at the center position of the longitudinal symmetry axis of the UAV; an opening module, configured to carry the UAV to a preset height in the air, release it in the wing-unfolded attitude, and then open the stability augmentation parachute; a cutting module, configured to cut off the stability augmentation parachute after the UAV adjusts its own attitude to complete the dive and level-off operation.

[0013] In a third aspect, an embodiment of the present application provides a server for enhancing the static stability of a UAV, including a memory and a processor; the memory is used to store computer-executable instructions; the processor is used to execute the computer-executable instructions to implement the method described in the first aspect or any possible implementation manner of the first aspect.

[0014] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores executable instructions, and when a computer executes the executable instructions, it can implement the method described in the first aspect or any possible implementation manner of the first aspect.

[0015] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects: The embodiments of the present application provide a method for enhancing the static stability of a UAV, obtaining the pitch moment and yaw moment of the UAV and the combined body of the UAV and the stability augmentation parachute, and performing handling and stability calculation and analysis, and determining the force-bearing area and the length of the parachute ropes of the stability augmentation parachute based on the results of the handling and stability calculation and analysis. Install the stability augmentation parachute at the tail of the UAV, and its hanging point is located at the center position of the longitudinal symmetry axis of the UAV. Carry the UAV to a preset height in the air, release it in the wing-unfolded attitude, and then open the stability augmentation parachute. After the UAV adjusts its own attitude to complete the dive and level-off operation, cut off the stability augmentation parachute. The present application enhances the stability of the UAV through a stability augmentation parachute without changing the aerodynamic shape of the UAV. And the test processing cycle of adding a stability augmentation parachute is short, and test verification can be quickly carried out. It solves the problem of how to enhance the stability of a UAV without changing the aerodynamic shape of the UAV to reduce the risk of accidents caused by control divergence during flight. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments of the present application or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Schematic diagram of the throwing flight technology provided by the embodiment of the present application; Figure 2 Graph of the change relationship of the yaw moment coefficient of the unmanned aerial vehicle with the angle of attack and the sideslip angle provided by the embodiment of the present application; Figure 3 Flowchart of a method for enhancing the static stability of an unmanned aerial vehicle provided by the embodiment of the present application; Figure 4 Schematic diagram of installing a stability augmentation parachute at the tail of the unmanned aerial vehicle provided by the embodiment of the present application; Figure 5 Schematic diagram of the radius of the stability augmentation parachute provided by the embodiment of the present application; Figure 6 Schematic diagram of a device for enhancing the static stability of an unmanned aerial vehicle provided by the embodiment of the present application; Figure 7 Schematic diagram of a server for enhancing the static stability of an unmanned aerial vehicle provided by the embodiment of the present application. Detailed implementation manners

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0019] The following explains some technologies related to the embodiments of the present application to facilitate understanding. It should be considered that they are merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described here without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, some descriptions of well-known functions and structures are omitted in the following description.

[0020] Figure 1Schematic diagram of the throwing flight technology provided by the embodiments of the present application. Taking a large aspect ratio unmanned aerial vehicle as an example, the present application introduces its throwing flight technology. This technology allows the unmanned aerial vehicle to be released from an aerial vehicle in a nose-down manner, perform a throwing flight, achieve a smooth dive-to-level operation, and finally fly autonomously along a predetermined route. Among them, the aerial vehicle may include a parachute, a hot air balloon or other load-bearing aircraft.

[0021] In order to smoothly transition the unmanned aerial vehicle from a vertically downward state to a horizontal flight state, the dive-to-level operation process is divided into two stages, namely the front stage of dive-to-level (stage 1) and the end stage of dive-to-level (stage 2). In the front stage of dive-to-level (stage 1), the unmanned aerial vehicle is released from the aerial vehicle in a nose-down attitude, the initial velocity in the nose direction is 0, and then the unmanned aerial vehicle starts to accelerate in free fall downward, converting gravitational potential energy into kinetic energy, and the speed gradually increases. In the end stage of dive-to-level (stage 2), the control surfaces are used to gradually lift the head of the unmanned aerial vehicle, changing the unmanned aerial vehicle from a vertically downward state to a horizontal flight state.

[0022] During the entire dive-to-level operation process, the speed of the unmanned aerial vehicle is relatively small in the front stage of dive-to-level (stage 1), and its stability is relatively poor, posing higher requirements for the time-domain and frequency-domain indicators of the control quality. Especially in terms of the heading static stability, the unmanned aerial vehicle shows obvious deficiencies. In the end stage of dive-to-level (stage 2), the speed is relatively fast, and the requirements for flight control are relatively high. The control law design of the flight control needs to meet relatively high indicators in terms of stability margin.

[0023] Figure 2 Graph showing the relationship between the yaw moment coefficient of the unmanned aerial vehicle provided by the embodiments of the present application and the angle of attack and sideslip angle. It can be seen from the graph that when the angle of attack is relatively small (such as Alpha = 0°, 2°), the yaw moment coefficient of the unmanned aerial vehicle generally shows an upward trend with the sideslip angle, indicating that the unmanned aerial vehicle has heading static stability under these angle-of-attack conditions. However, when the angle of attack is greater than 4°, the yaw moment coefficient generally shows a downward trend with the increase of the sideslip angle, indicating that the unmanned aerial vehicle becomes heading statically unstable under these angle-of-attack conditions. Figure 2 Alpha in it is the angle of attack.

[0024] Table 1 shows the time-domain and frequency-domain characteristic table provided by the embodiments of the present application under normal working conditions (the stability is the best when the angle of attack is 0°). Taking the course stability as an example, it is analyzed that the Dutch roll mode damping ratio is only 0.291 (the corresponding Dutch roll mode damping ratio can also be calculated for longitudinal stability), which means that the system has a weak ability to suppress vibration, the vibration is relatively intense, and it is difficult to stabilize quickly. Further, through parameters such as characteristic roots and natural frequencies, the overshoot of the system's time-domain characteristics is calculated to be 38.5%, which also indicates that there are large fluctuations in the system during the response process. Moreover, during the dive-to-level operation of the UAV, the change in the angle of attack is relatively intense, further exacerbating the risk of UAV control divergence. Therefore, in order to improve the stability and control performance of the UAV, it is necessary to adjust its body characteristics to meet the time-domain and frequency-domain design indicators of the flight control law. Specifically, it is necessary to adjust the Dutch roll mode damping ratio to around 0.7 and control the overshoot within the ideal range of 5% to ensure that the UAV can maintain a stable and reliable flight state during the dive-to-level operation.

[0025] Table 1

[0026] The embodiments of the present application provide a method for enhancing the static stability of a UAV, as Figure 3 shown, the method includes steps S101 to S104. Among them, Figure 3 This is only an execution order shown in the embodiments of the present application and does not represent the only execution order of a method for enhancing the static stability of a UAV. Under the condition that the final result can be achieved, Figure 3 the steps shown can be executed in parallel or reversed.

[0027] S101: Obtain the pitching moment and yaw moment of the combined body of the UAV and the stability augmentation parachute and conduct handling stability calculation and analysis, and determine the force area and shroud line length of the stability augmentation parachute based on the results of the handling stability calculation and analysis.

[0028] S102: Install the stability augmentation parachute at the tail of the UAV, and its suspension point is located at the center position of the longitudinal symmetry axis of the UAV.

[0029] Without changing the aerodynamic shape of the UAV, the present application installs the stability augmentation parachute at the tail of the UAV to improve the stability of the UAV and reduce the risk of UAV control divergence. The suspension point of the parachute is accurately positioned at the center position of the longitudinal symmetry axis of the UAV, that is, the center of the X-axis of the UAV. This position is selected to ensure that the force exerted by the stability augmentation parachute on the UAV is evenly distributed, avoiding unbalanced moments caused by installation position deviations, thereby ensuring the stability of the UAV during flight.

[0030] Figure 4Schematic diagram of installing a stability augmentation parachute at the tail of a drone provided by an embodiment of this application. The X, Y, and Z axes are marked in the figure, and the parachute attachment point (point P) is located at the center of the longitudinal symmetry axis of the drone, that is, the center of the X axis of the drone. is the aerodynamic focus of the drone, is the distance between the parachute attachment point and the aerodynamic focus of the drone.

[0031] Obtain the pitch moment and yaw moment of the drone and the drone-parachute combination and perform handling and stability calculation analysis. Based on the results of the handling and stability calculation analysis, determine the force area and parachute rope length of the stability augmentation parachute, including the following steps. Superimpose the pitch moment and yaw moment of the stability augmentation parachute onto the pitch moment and yaw moment of the drone respectively to obtain the pitch moment and yaw moment of the drone-parachute combination. Perform handling and stability calculation analysis based on the pitch moment and yaw moment of the drone-parachute combination. Determine the force area and parachute rope length of the stability augmentation parachute with the damping ratio and overshoot of the drone-parachute combination as the constraint conditions of the results of the handling and stability calculation analysis.

[0032] Specifically, in order to accurately control the influence of the stability augmentation parachute on the moment of the drone, it is necessary to determine the force area and parachute rope length of the stability augmentation parachute. The calculation formula for the force area of the stability augmentation parachute is: . Wherein, is the force area of the stability augmentation parachute, is the radius of the stability augmentation parachute, is a mathematical constant. During flight, the stability augmentation parachute will generate resistance according to the airflow direction, thereby changing the pitch moment and yaw moment of the drone.

[0033] Figure 5 Schematic diagram of the radius of the stability augmentation parachute provided by an embodiment of this application. Point Q in the figure is the aerodynamic force application point of the stability augmentation parachute, is the radius of the stability augmentation parachute.

[0034] The calculation formula for the pitch moment of the stability augmentation parachute is: . Wherein, is the pitch moment of the stability augmentation parachute, is the drag coefficient of the stability augmentation parachute, is the force area of the stability augmentation parachute, is the distance between the parachute attachment point and the aerodynamic focus of the drone, is the angle of attack of the drone.

[0035] It should be noted that the drag coefficient of the stability augmentation parachute is related to the material of the stability augmentation parachute itself.

[0036] The calculation formula for the yaw moment of the stability augmentation parachute is: . Wherein, is the sideslip angle of the drone. . is the radius of the stability augmentation parachute, is a mathematical constant.

[0037] Specifically, the pitch moment and yaw moment of the stability augmentation parachute are respectively superimposed on the pitch moment and yaw moment of the unmanned aerial vehicle to obtain the pitch moment and yaw moment of the parachute - UAV combination, that is , . Among them, is the pitch moment of the parachute - UAV combination, is the yaw moment of the parachute - UAV combination.

[0038] It should be noted that the parachute - UAV combination has a new moment balance state, which is relative to the original moment balance state of the unmanned aerial vehicle. When the stability augmentation parachute is not installed, the unmanned aerial vehicle relies on factors such as its own aerodynamic layout and center - of - gravity position, and its pitch moment and yaw moment are in a balanced state, enabling the unmanned aerial vehicle to maintain a relatively stable flight attitude.

[0039] In this application, taking a high - aspect - ratio unmanned aerial vehicle as an example, the pitch moment and yaw moment of the stability augmentation parachute are respectively superimposed on the pitch moment and yaw moment of the unmanned aerial vehicle. After forming a new moment balance state, the handling and stability calculation and analysis are carried out based on the pitch moment and yaw moment of the parachute - UAV combination. When the stressed area of the stability augmentation parachute is 0.9 m 2 , and the distance between the parachute suspension point and the aerodynamic focus of the unmanned aerial vehicle is 1.2 m, the calculation results of the handling and stability characteristics after adding the stability augmentation parachute are shown in Table 2. Table 2 is the time - domain and frequency - domain characteristic table of the new moment balance state of the parachute - UAV combination provided by the embodiment of this application. After adding the stability augmentation parachute, the course stability of the unmanned aerial vehicle changes. The course is stable within the range of the angle of attack used, and the damping ratio and overshoot of the parachute - UAV combination are within the ideal range, effectively improving the course stability of the unmanned aerial vehicle. It should be noted that the damping ratio in this application is the Dutch roll modal damping ratio.

[0040] Table 2

[0041] Specifically, the size of the stressed area of the stability augmentation parachute is not the larger the better. An overly large stressed area of the stability augmentation parachute may bring adverse effects such as additional resistance and interference with aerodynamic characteristics. Therefore, through simulation flight means, combined with the aerodynamic characteristics of the unmanned aerial vehicle to be tested, it can be judged by speed, and then the reasonable range of the stressed area of the stability augmentation parachute can be determined.

[0042] This application also includes verifying whether the force-bearing area of the stability augmentation parachute meets the requirements based on preset principles through simulated flight. The preset principles specifically include: after the UAV completes the dive-to-level operation, the stability augmentation parachute is cut off, and the minimum speed of the UAV is greater than or equal to a preset multiple of the stall speed of the UAV, and at the same time, the maximum speed of the UAV is less than or equal to the flutter speed of the UAV. Among them, the preset multiple is greater than 1. The preset multiple can be set to 1.3 times. When the speed of the UAV meets the preset principles, the force-bearing area of the stability augmentation parachute meets the requirements.

[0043] Specifically, the stall speed of the UAV refers to the minimum flight speed required for the UAV to maintain normal lift during flight. When the speed of the UAV is lower than the stall speed, the lift will not be able to support the weight of the UAV, resulting in the UAV entering a stall state, and dangerous situations such as a sharp drop in altitude and out-of-control attitude will occur. Flutter is a self-excited vibration phenomenon generated by the coupling of aerodynamic force, elastic force, and inertial force on the UAV structure. The flutter speed is the critical speed at which the UAV undergoes flutter. When the flight speed exceeds the flutter speed, the structural vibration will continue to intensify, which may cause structural damage and lead to catastrophic consequences.

[0044] Furthermore, setting a safety margin of 1.3 times the stall speed can prevent the speed of the UAV from falling into the stall range and can ensure that the UAV can still maintain lift balance under external interference. The maximum speed of the UAV being less than or equal to the flutter speed of the UAV can prevent structural flutter caused by the excessive speed of the UAV.

[0045] S103: Carry the UAV to a preset altitude in the air, release it in the wing-unfolded attitude, and then open the stability augmentation parachute.

[0046] Carrying the UAV to a preset altitude in the air, releasing it in the wing-unfolded attitude, and then opening the stability augmentation parachute includes the following steps. When the UAV is in the state of folded wings, it is carried to the preset altitude by an aerial vehicle. When the UAV reaches the preset altitude, the UAV performs a wing-unfolding action. After the wing-unfolding action is completed, the aerial vehicle releases the UAV. The UAV detects the release signal and opens the stability augmentation parachute. At this time, the body attitude is adjusted when the propellers are in a stationary state.

[0047] S104: After the UAV adjusts its own attitude to complete the dive-to-level operation, cut off the stability augmentation parachute.

[0048] Specifically, during the dive-to-level operation of the UAV, the stability augmentation parachute plays a role in enhancing the stability of the UAV. After the UAV completes the dive-to-level operation, the stability augmentation parachute is cut off in the air, and it can fly autonomously according to the predetermined route.

[0049] After the UAV adjusts its own attitude to complete the dive leveling operation, the stability augmentation parachute is cut off, including: The UAV executes the dive leveling operation by adjusting its own attitude, gradually reduces the pitch angle, and transitions to the horizontal flight state. When the UAV completes the dive leveling operation, the stability augmentation parachute is cut off, the propeller is turned on, and the normal flight process is executed.

[0050] Specifically, the judgment criterion for the UAV to complete the dive leveling operation is that the pitch angle of the UAV is greater than a preset angle and the duration is greater than a preset time.

[0051] In this application, the preset angle is set to -5°, and the preset time is set to 1 s. That is, when the UAV is executing the dive leveling operation, its pitch angle is monitored in real time. Once the pitch angle is greater than -5° and this pitch angle state lasts for more than 1 s, it is determined that the UAV has completed the dive leveling operation.

[0052] Without changing the aerodynamic shape of the UAV, this application enhances the stability of the UAV through the stability augmentation parachute. And the test processing cycle of adding the stability augmentation parachute is short, and the test verification can be carried out quickly. After adding the stability augmentation parachute, it can also avoid the problem that the speed of the UAV is too large after the UAV completes the dive leveling operation due to the too long time of the dive leveling operation of the UAV, which is likely to cause the UAV to flutter.

[0053] The embodiment of this application also provides a device 600 for enhancing the static stability of the UAV, as Figure 6 shown. This device includes: a determination module 601, an installation module 602, an opening module 603, and a cutting module 604.

[0054] The determination module 601 obtains the pitch moment and yaw moment of the UAV and the parachute-aircraft combination of the stability augmentation parachute and performs handling stability calculation and analysis, and determines the force area and suspension line length of the stability augmentation parachute based on the results of the handling stability calculation and analysis.

[0055] The installation module 602 is used to install the stability augmentation parachute at the tail of the UAV, and its hanging point is located at the center position of the longitudinal symmetry axis of the UAV.

[0056] The opening module 603 is used to carry the UAV to a preset height in the air, release it in the wing-unfolding attitude, and then open the stability augmentation parachute.

[0057] The cutting module 604 is used to cut off the stability augmentation parachute after the UAV adjusts its own attitude to complete the dive leveling operation.

[0058] Some of the modules in the device described in this application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform specific tasks or implement specific abstract data types. This application can also be practiced in a distributed computing environment, where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0059] The devices or modules illustrated in the above application embodiments can be specifically implemented by computer chips or entities, or by products with certain functions. For the convenience of description, when describing the above devices, they are divided into various modules according to functions and described separately. When implementing the embodiments of this application, the functions of each module can be implemented in the same or multiple software and / or hardware. Of course, the module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0060] The methods, devices or modules described in this application can be implemented in the form of computer-readable program code. The controller can be implemented in any appropriate manner. For example, the controller can take the form of, for example, a microprocessor or a processor, and a computer-readable medium storing computer-readable program code (such as software or firmware) executable by the (micro)processor, logic gates, switches, application specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program code, the method steps can be logically programmed to enable the controller to be implemented in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, and embedded microcontrollers to achieve the same function. Therefore, such a controller can be regarded as a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as both software modules for implementing the method and the structures within the hardware component.

[0061] As Figure 7As shown in the figure, an embodiment of the present application further provides a server for enhancing the static stability of an unmanned aerial vehicle, including a memory 701 and a processor 702; the memory 701 is used to store computer-executable instructions; the processor 702 is used to execute the computer-executable instructions to implement the method for enhancing the static stability of an unmanned aerial vehicle described above in the embodiments of the present application.

[0062] An embodiment of the present application further provides a computer-readable storage medium storing executable instructions, and when a computer executes the executable instructions, it can implement the method for enhancing the static stability of an unmanned aerial vehicle described above in the embodiments of the present application.

[0063] From the description of the above embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software plus necessary hardware. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, or can also be reflected in the implementation process of data migration. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disc, etc., and includes several instructions for causing a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the method described in the embodiments of the present application.

[0064] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. All or part of the present application can be used in many general or special computer system environments or configurations.

[0065] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A method for enhancing the static stability of an unmanned aerial vehicle, characterized in that, Including: Obtain the pitch moment and yaw moment of the combined body of the drone and the stability augmentation parachute, and perform handling and stability calculation and analysis. Based on the results of the handling and stability calculation and analysis, determine the force-bearing area and the length of the parachute ropes of the stability augmentation parachute; Install the stability augmentation parachute at the tail of the drone, and its hanging point is located at the center position of the longitudinal symmetry axis of the drone; Carry the drone to a preset altitude in the air, release it in the wing-unfolded attitude, and then open the stability augmentation parachute; After the drone adjusts its own attitude to complete the dive-to-level operation, cut off the stability augmentation parachute.

2. The method for enhancing the static stability of an unmanned aerial vehicle according to claim 1, wherein The obtaining the pitch moment and yaw moment of the combined body of the drone and the stability augmentation parachute, and performing handling and stability calculation and analysis, and determining the force-bearing area and the length of the parachute ropes of the stability augmentation parachute based on the results of the handling and stability calculation and analysis includes: Superimpose the pitch moment and yaw moment of the stability augmentation parachute onto the pitch moment and yaw moment of the drone respectively to obtain the pitch moment and yaw moment of the combined body of the drone and the parachute; Perform handling and stability calculation and analysis based on the pitch moment and yaw moment of the combined body of the drone and the parachute; Taking the damping ratio and overshoot of the combined body of the drone and the parachute as the constraint conditions of the results of the handling and stability calculation and analysis, determine the force-bearing area and the length of the parachute ropes of the stability augmentation parachute.

3. The method for enhancing the static stability of an unmanned aerial vehicle according to claim 2, wherein The calculation formula for the pitching moment of the stability augmentation parachute is as follows: ; where is the pitching moment of the stability augmentation parachute, is the drag coefficient of the stability augmentation parachute, is the force-bearing area of the stability augmentation parachute, is the distance between the parachute suspension point and the aerodynamic focus of the UAV, is the angle of attack of the UAV; The calculation formula for the yaw moment of the stability augmentation parachute is as follows: ; where is the sideslip angle of the UAV; Among them, ; is the radius of the stability augmentation parachute, is a mathematical constant.

4. The method for enhancing the static stability of an unmanned aerial vehicle according to claim 1, wherein It also includes verifying whether the force-bearing area of the stability augmentation parachute meets the requirements through simulated flight based on preset principles. The preset principles specifically include: After the drone completes the dive-to-level operation, cut off the stability augmentation parachute. The minimum speed of the drone is greater than or equal to a preset multiple of the stall speed of the drone, and at the same time, the maximum speed of the drone is less than or equal to the flutter speed of the drone; where the preset multiple is greater than 1.

5. The method for enhancing the static stability of an unmanned aerial vehicle according to claim 1, wherein The carrying the drone to a preset altitude in the air, releasing it in the wing-unfolded attitude, and then opening the stability augmentation parachute includes: When the drone is in the state of folded wings, it is carried by an air vehicle to a preset altitude; When the drone reaches the preset altitude, the drone performs a wing-unfolding action; After the wing-unfolding action is completed, the air vehicle releases the drone; The drone detects the release signal and opens the stability augmentation parachute. At this time, adjust the body attitude when the propeller is in a stationary state.

6. The method for enhancing the static stability of an unmanned aerial vehicle according to claim 1, characterized in that The cutting off the stability augmentation parachute after the drone adjusts its own attitude to complete the dive-to-level operation includes: The drone performs the dive-to-level operation by adjusting its own attitude, gradually reduces the pitch angle, and transitions to the horizontal flight state; When the drone completes the dive-to-level operation, cut off the stability augmentation parachute, turn on the propeller, and execute the normal flight process.

7. The method for enhancing the static stability of an unmanned aerial vehicle according to claim 1, characterized in that, The judgment criterion for the drone to complete the dive-to-level operation is that the pitch angle of the drone is greater than a preset angle and the duration is greater than a preset time.

8. A device for enhancing the static stability of an unmanned aerial vehicle, characterized in that, Including: A determination module for obtaining the pitch moment and yaw moment of the combined body of the drone and the stability augmentation parachute, performing handling and stability calculation and analysis, and determining the force-bearing area and the length of the parachute ropes of the stability augmentation parachute based on the results of the handling and stability calculation and analysis; An installation module for installing the stability augmentation parachute at the tail of the drone, and its hanging point is located at the center position of the longitudinal symmetry axis of the drone; An opening module for carrying the drone to a preset altitude in the air, releasing it in the wing-unfolded attitude, and then opening the stability augmentation parachute; A cutting-off module for cutting off the stability augmentation parachute after the drone adjusts its own attitude to complete the dive-to-level operation.

9. A server for enhancing the static stability of a drone, characterized in that, Including a memory and a processor; The memory is used to store computer-executable instructions; The processor is used to execute the computer-executable instructions to implement the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores executable instructions, and when the computer executes the executable instructions, it can implement the method according to any one of claims 1-7.

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