Fixed-wing UAV anti-tipping front wheel limiting method and device and UAV

Abstract

This invention discloses a method, device, and drone for limiting the front wheel's deflection during gliding anti-tipping of a fixed-wing unmanned aerial vehicle (UAV). The limiting method includes: calculating the front wheel's deflection angle. d ; Calculate the maximum front wheel deflection angle; Based on the front wheel deflection angle d The maximum front wheel deflection angle is used to determine the front wheel control angle. This angle is then input into the PID controller, enabling it to perform PID control calculations. The PID controller then controls the flight control module to adjust the UAV's front wheel actuator to the specified control angle. Different front wheel angle limits are obtained based on varying taxiing speeds to optimize the UAV's correction performance while preventing tipping, thereby improving correction efficiency.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a method, device, and UAV for limiting the front wheel width to prevent rollover during gliding of a fixed-wing UAV. Background Technology

[0002] A fixed-wing unmanned aerial vehicle (UAV) is a heavier-than-air unmanned aircraft that takes off and lands via a runway, generates thrust or pull through a power unit, and produces lift through its fixed wings, flying within the atmosphere. Due to their high flight efficiency and long range, fixed-wing UAVs are widely used in many fields such as military reconnaissance, logistics transportation, and environmental monitoring.

[0003] However, during takeoff and landing, fixed-wing drones need to glide at high speeds on the runway. This process is susceptible to various factors, such as crosswinds, uneven runways, and operational errors, which can cause the front wheels to oversteer, leading to the aircraft tipping over and causing damage to the drone or even casualties.

[0004] In existing technologies, fixed-wing UAVs typically use a nose wheel, rudder, or a combination of both for lateral correction. For example, when the UAV veers to one side of the runway, the flight control computer controls the UAV to veer to the opposite side, thereby controlling the UAV to taxi as close to the runway centerline as possible. During this correction process, the aircraft will be subject to centrifugal force when turning, resulting in a certain overturning moment; in order to maintain the UAV's balance mode, the main wheels need to actively generate anti-overturning moment to counteract the effect of the overturning moment.

[0005] For example, when a fixed-wing UAV is correcting its course, the conventional anti-tipping limiting strategy is as follows: Based on past experience, a fixed front wheel steering angle is used as the limiting factor, usually using a safe angle (e.g., 1°) corresponding to the takeoff speed as the limiting condition. When the UAV's taxiing speed is greater than a certain value, the maximum deflection angle of the front wheel is fixed, ensuring the UAV's operational safety. However, the situation at different taxiing speeds is not considered, so the correction efficiency is low. When the UAV's speed has not reached the takeoff speed, the front wheel cannot perform maximum correction efficiency due to the angle limitation, resulting in the generation of the UAV's taxiing lateral deviation.

[0006] Therefore, researching an effective method for limiting the front wheel width during high-speed gliding of fixed-wing UAVs is of great practical significance. Summary of the Invention

[0007] In view of this, the present invention aims to provide a method, device and drone for limiting the front wheel of a fixed-wing UAV to prevent rollover during gliding. By combining a mechanical limiting mechanism and an intelligent control strategy, the steering angle of the front wheel during high-speed gliding is effectively limited, thereby improving the stability and safety of the UAV.

[0008] To address the aforementioned problems, the first objective of this invention is to provide a method for limiting the front wheel of a fixed-wing unmanned aerial vehicle (UAV) to prevent rollover during gliding, the method comprising:

[0009] Step S1: Based on the gliding speed v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d ;

[0010] Step S2: Based on the fact that the anti-tipping moment of the UAV must balance the magnitude of the centrifugal moment, calculate the maximum front wheel deflection angle. ;

[0011] Step S3: Based on the front wheel deflection angle d and maximum front wheel deflection angle Determine the front wheel control angle ;

[0012] Step S4: Input the front wheel control angle to the PID controller. So that the PID controller can adjust the front wheel control angle accordingly. Perform PID control calculations;

[0013] Step S5: The PID controller controls the flight control module to adjust the UAV's front wheel actuator to the front wheel control angle. .

[0014] Furthermore, in step S1, the gliding speed-based... v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d , specifically including:

[0015] Step S 11 The drone's gliding speed is obtained in real time via a pitot tube mounted on the leading edge of the nose. v * Crosswind speed is obtained in real time by a wind speed sensor installed on the top of the drone fuselage. v side The deviation between the UAV and the runway centerline is calculated in real time by a fiber-optic integrated navigation device in real-time dynamic differential positioning and navigation mode. e The attitude angle of the drone is obtained in real time by a fiber optic gyroscope installed on the drone. i ;

[0016] Step S12 According to the stated gliding speed v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Determine the gain adjustment value;

[0017] Step S 13 The proportional gain, integral gain, and derivative gain of the PID controller are adjusted using the gain adjustment value.

[0018] Step S 14 The front wheel deflection angle is calculated using the output formula of the PID controller. d .

[0019] Furthermore, in step S 14 The output formula of the PID controller is as follows:

[0020]

[0021] in, d It's the front wheel deflection angle. It is proportional gain. It is integral gain. It is the differential gain.

[0022] Furthermore, in step S2, the maximum front wheel deflection angle The calculation expression is:

[0023]

[0024] in, It's the drone's gravity. r air density, v For the drone's flight speed, S For wing area, The lift coefficient, a This refers to the distance between the left and right main landing gears. b This refers to the distance between the drone's nose landing gear and main landing gear.

[0025] Furthermore, in step S3, the method based on the front wheel deflection angle... d and maximum front wheel deflection angle The size determines the front wheel control angle. , specifically including:

[0026] Current wheel deflection angle d Not greater than the maximum front wheel deflection angle At that time, output the front wheel control angle. equal to the front wheel deflection angle d ;

[0027] Current wheel deflection angle d Greater than the maximum front wheel deflection angle At that time, output the front wheel control angle. Equal to the front wheel deflection angle d Maximum front wheel deflection angle of the same polarity .

[0028] Furthermore, in step S4, the PID control operation includes proportional control operation, integral control operation, and derivative control operation.

[0029] Furthermore, in step S5, the front wheel actuation mechanism includes a servo motor or a motor. The servo motor or motor adjusts its output angle according to the received PWM signal from the flight control module. The output angle of the servo motor or motor is transmitted to the front wheel steering mechanism through a mechanical transmission mechanism to achieve the deflection of the front wheel.

[0030] The second objective of this invention is to provide a front wheel limiting device for anti-tipping during gliding of a fixed-wing unmanned aerial vehicle, comprising:

[0031] The first calculation module is used to calculate based on gliding speed. v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d ;

[0032] The second calculation module is used to calculate the maximum front wheel deflection angle based on the fact that the anti-overturning moment of the UAV must balance the centrifugal moment. ;

[0033] The comparison and determination module is used to determine the front wheel deflection angle. d and the maximum front wheel deflection angle The size determines the front wheel control angle. ;

[0034] The control parameter adjustment module is used to adjust the front wheel control angle based on the input to the PID controller. So that the PID controller can adjust the front wheel control angle accordingly. Perform PID control calculations;

[0035] The deflection angle control module is used by the PID controller to control the flight control module to adjust the front wheel actuator of the UAV to the target front wheel deflection angle.

[0036] A third objective of this invention is to provide a fixed-wing unmanned aerial vehicle (UAV) comprising: a front wheel limiting device for preventing rollover during gliding as described above.

[0037] A fourth objective of this invention is to provide a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the aforementioned method for limiting the front wheel width of a fixed-wing unmanned aerial vehicle (UAV) to prevent tipping.

[0038] Compared with the prior art, the present invention has significant advantages and beneficial effects, specifically reflected in the following aspects:

[0039] The fixed-wing UAV anti-tipping front wheel limiting method in this invention includes the following steps: based on the gliding speed v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d The anti-overturning moment of the UAV must balance the magnitude of the centrifugal moment, and the maximum front wheel deflection angle must be calculated. Based on the front wheel deflection angle d and maximum front wheel deflection angle Determine the front wheel control angle Input the front wheel control angle to the PID controller. So that the PID controller can adjust according to the front wheel control angle. Perform PID control calculations; the PID controller controls the flight control module to adjust the UAV's front wheel actuator to the front wheel control angle. Therefore, inputting the front wheel control angle into the PID controller and having it perform PID control calculations based on that angle is a crucial step in achieving precise control of a fixed-wing UAV during high-speed gliding. By calculating the error between the target value and the actual value, the PID controller generates a control signal based on a combination of proportional, integral, and derivative control methods, driving the actuator to adjust the front wheel deflection angle. Through parameter adjustment, sensor calibration, fault detection and protection, and simulation and experimental verification, the stability and reliability of the control system can be ensured, improving the safety and stability of the UAV during high-speed gliding, effectively preventing the UAV from tipping over, and greatly improving the correction efficiency. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall process of the fixed-wing UAV anti-tipping front wheel amplitude limiting method in an embodiment of the present invention;

[0041] Figure 2 This is step S in the embodiment of the present invention.100 Detailed flowchart;

[0042] Figure 3 This is a schematic diagram of the structure of the anti-tipping front wheel limiting device for fixed-wing UAVs in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the structure of a fixed-wing UAV in an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the anti-tipping front wheel limiting curve of a large fixed-wing UAV in an embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram showing the curves of the UAV's taxiing speed, UAV's front wheel angle, and UAV's lateral deviation distance from the middle of the runway before the anti-overturning front wheel limiting method is adopted in this embodiment of the invention.

[0046] Figure 7 This is a schematic diagram showing the curves of the drone's taxiing speed, drone's front wheel angle, and drone's lateral deviation distance from the runway center after adopting the anti-tipping front wheel limiting method in this embodiment of the invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 100- Fixed-wing UAV gliding anti-tipping front wheel limiting device; 110- First calculation module; 120- Second calculation module; 130- Comparison and determination module; 140- Control parameter adjustment module; 150- Yaw angle control module;

[0049] 200 - Fixed-wing unmanned aerial vehicle; 300 - Processor; 400 - Memory. Detailed Implementation

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0051] A fixed-wing drone is a type of drone whose wings are fixed and whose outer wing sweep angle can be automatically or manually adjusted according to speed.

[0052] During the high-speed takeoff and landing phase, fixed-wing drones may deviate from the runway centerline due to external factors such as crosswinds, posing a risk of running off the runway. For example, when encountering a right-side wind, the drone will veer to the right of the runway; when encountering a left-side wind, it will veer to the left. To ensure that the drone does not deviate from the runway under the influence of external factors and maintains its deviation from the runway centerline within a certain range, appropriate correction strategies must be adopted to control the drone and guide it closer to the runway centerline.

[0053] However, for drones that taxi at high speeds, large turning angles may cause the aircraft to overturn or roll over. Therefore, different turning angle limits are used at different taxiing speeds to prevent fixed-wing drones from overturning while improving the correction efficiency.

[0054] Please see Figure 1 As shown, this embodiment of the invention provides a method for limiting the front wheel of a fixed-wing unmanned aerial vehicle (UAV) to prevent overturning during high-speed gliding. The limiting method includes:

[0055] Step S1: Based on gliding speed v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d ;

[0056] In this step, the gliding speed v * It is an important parameter for calculating the front wheel deflection angle because it directly affects the steering response speed and the magnitude of the steering angle; crosswind speed. v side Front wheel yaw angle d The effect of crosswinds is essentially a "heading correction compensation" relationship. The stronger the crosswind, the greater the required deflection angle of the nose wheels; otherwise, the drone will be blown off the runway centerline. To counteract the deflection caused by the crosswind, the nose wheels must deflect in the opposite direction in advance, achieving nose pointing correction and lateral force balance. When the drone is taxiing at high speed, if there is a centerline deviation... e Then trajectory correction control is required.

[0057] Step S2: Based on the fact that the anti-tipping moment of the UAV must balance the magnitude of the centrifugal moment, calculate the maximum front wheel deflection angle. ;

[0058] In this step, under the constraint of "no overturning", the steering process during high-speed sliding is simplified into a two-degree-of-freedom rigid body model of "sideslip-roll". By setting the anti-overturning moment ≥ centrifugal moment, the critical maximum front wheel deflection angle can be solved. .

[0059] Step S3: Based on the front wheel deflection angle d and maximum front wheel deflection angle Determine the front wheel control angle ;

[0060] In this step, a front wheel control angle is given that is both safe and can track the target as much as possible, between the calculated "theoretical front wheel deflection angle" (given by upper-level algorithms such as trajectory tracking and crosswind compensation) and the "anti-rollover upper limit" (obtained from step S2). .

[0061] Step S4: Input the front wheel control angle to the PID controller So that the PID controller can adjust according to the front wheel control angle. Perform PID control calculations;

[0062] In this step, the front wheel control angle is input to the PID controller in real time. During the high-speed taxiing phase, the runway centerline error is further reduced, thereby reducing the probability of overturning by another order of magnitude.

[0063] Step S5: The PID controller controls the flight control module to adjust the UAV's front wheel actuator to the front wheel control angle. .

[0064] Therefore, inputting the front wheel control angle into the PID controller and instructing it to perform PID control calculations based on that angle is a crucial step in achieving precise control of a fixed-wing UAV during high-speed gliding. By calculating the error between the target value and the actual value, the PID controller generates a control signal based on a combination of proportional, integral, and derivative control methods, driving the actuator to adjust the front wheel deflection angle. Through parameter adjustment, sensor calibration, fault detection and protection, and simulation and experimental verification, the stability and reliability of the control system can be ensured, improving the safety and stability of the UAV during high-speed gliding.

[0065] For further details, please refer to Figure 2 As shown, in some embodiments of the present invention, in step S1, the step based on the sliding speed... v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d , specifically including:

[0066] Step S 11 The front wheel's coasting speed is obtained in real time via a pitot tube installed on the leading edge of the nose. v * Crosswind speed is obtained in real time by a wind speed sensor installed on the top of the drone fuselage. v sideThe deviation between the UAV and the runway centerline is calculated in real time by a fiber-optic integrated navigation device in the real-time dynamic differential positioning (RTK) navigation mode. e The attitude angle of the drone is obtained in real time by a fiber optic gyroscope installed on the drone. i ;

[0067] In this step, sensors (such as speed sensors, wind speed sensors, fiber optic integrated navigation devices, fiber optic gyroscopes, etc.) are used to monitor the UAV's taxiing speed, crosswind speed, runway centerline deviation, UAV attitude angle, and other state parameters in real time. The speed sensor is a fiber optic integrated navigation device based on an inertial measurement unit (IMU). The measurement or estimation of crosswind speed needs to take into account the direction and magnitude of the crosswind, because the crosswind will cause a lateral deviation in the UAV's taxiing trajectory. The runway centerline deviation is used to keep the UAV within the runway safety zone during high-speed taxiing to prevent deviation from the runway or overturning. Changes in the UAV's attitude angle will cause an instantaneous change in the vertical distance h between the center of gravity and the ground, which will affect the calculation of the anti-overturning moment in step S2, preventing overestimation or underestimation of the anti-overturning capability due to pitching up / down.

[0068] Step S 12 Based on gliding speed v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Determine the gain adjustment value;

[0069] In this step, during the high-speed gliding phase of the fixed-wing UAV, the following steps are taken: v * , v side , e , i The online calculation of the "gain adjustment value" of four real-time quantities ensures that the centrifugal torque is always below the anti-overturning limit, thus achieving optimal trajectory control under the premise of zero overturning, while balancing "trajectory accuracy" and "anti-overturning safety".

[0070] Step S 13 The proportional gain, integral gain, and derivative gain of the PID controller are adjusted using the gain adjustment value.

[0071] In this step, the gain adjustment value upgrades the PID from "fixed gain" to adaptive gain adjustment, maintaining centimeter-level trajectory accuracy and millisecond-level response without zero overturning.

[0072] Step S 14 The front wheel deflection angle is calculated using the output formula of the PID controller. d.

[0073] Furthermore, in some embodiments of the present invention, in step S 14 The output formula of the PID controller is as follows:

[0074]

[0075] in, d It is the front wheel deflection angle; It is the proportional gain, which determines the instantaneous correction force, and is measured in (° / °) or (μs / °). It is the integral gain, used to eliminate steady-state error, and its unit is (° / ·s) or (μs / ·s); is the differential gain, used to suppress overshoot and oscillation, with units of (·s / °) or (μs·s / °); e(t) is the error signal, i.e., the difference between the expected value and the actual value.

[0076] It is important to note that the PID controller is a common feedback controller widely used in various control systems, including flight control systems for unmanned aerial vehicles (UAVs). Its main function is to adjust the system output to the desired target value through a combination of proportional (P), integral (I), and derivative (D) control methods. The parameters of a PID controller (…) , , The parameters need to be adjusted and optimized according to the specific model of the drone and the actual operating environment. Parameter adjustments can be made through a combination of testing and simulation to ensure the stability and response speed of the control system.

[0077] Furthermore, in some embodiments of the present invention, in step S2, the maximum front wheel deflection angle The calculation expression is:

[0078]

[0079] in, It's the drone's gravity. r air density, v For the drone's flight speed, S For wing area, The lift coefficient, a This refers to the distance between the left and right main landing gears. b This refers to the distance between the drone's nose landing gear and main landing gear.

[0080] Specifically, a fixed-wing UAV experiences centrifugal force when turning, with the point of application located at the UAV's center of gravity. The formula for calculating the centrifugal force acting on a fixed-wing UAV is as follows:

[0081] (1)

[0082] Where: F c For centrifugal force, m For the quality of drones, v For the drone's flight speed, R This refers to the turning radius of the drone.

[0083] Due to the turning radius of fixed-wing drones R Front wheel turning angle The relationship between them is:

[0084] (2)

[0085] Where: R The turning radius of the drone. The turning angle of the front wheels. b This refers to the distance between the drone's nose landing gear and main landing gear.

[0086] Combining formulas (1) and (2), centrifugal force can be expressed as:

[0087] (3)

[0088] Therefore, the overturning moment caused by centrifugal force is:

[0089] (4)

[0090] In the formula, h The overturning moment is the height of the UAV's center of gravity;

[0091] To prevent the drone from tipping over, the anti-tipping moment must balance the centrifugal moment. This anti-tipping moment is generated by the main wheels; therefore, the magnitude of the anti-tipping moment is:

[0092] (5)

[0093] In the formula, a This refers to the spacing between the left and right main landing gears.

[0094] Due to the effective load W eff Lift due to gliding speed L The payload of the drone is reduced. W eff The size is:

[0095] (6)

[0096] In the formula, r air density, v For the drone's flight speed,S For wing area, This is the lift coefficient.

[0097] To prevent one side of the main wheel from lifting, the anti-overturning moment must be greater than or equal to the roll moment:

[0098] (7)

[0099] By reorganizing the above formulas, we can obtain the maximum front wheel deflection angle. The calculation expression is:

[0100] (8)

[0101] Therefore, for fixed-wing UAVs, the front wheel steering servo angle is limited according to formula (8), and different front wheel angle limits are obtained according to different gliding speeds, so as to match the best correction performance of the UAV under the premise of preventing the UAV from overturning.

[0102] Furthermore, in some embodiments of the present invention, in step S3, the method based on the front wheel deflection angle... d and maximum front wheel deflection angle The size determines the front wheel control angle. , specifically including:

[0103] Current wheel deflection angle d Not greater than the maximum front wheel deflection angle At that time, output the front wheel control angle. equal to the front wheel deflection angle d ;

[0104] Current wheel deflection angle d Greater than the maximum front wheel deflection angle At that time, output the front wheel control angle. Equal to the front wheel deflection angle d Maximum front wheel deflection angle of the same polarity .

[0105] Therefore, when the centrifugal torque has not yet reached the overturning limit, the system is in a safe zone, and no adjustments are needed. The desired angle can be directly used as the control angle output, ensuring trajectory accuracy while avoiding unnecessary performance loss. When the centrifugal torque has exceeded the overturning limit, further increasing the angle will inevitably lead to overturning; therefore, using the same polarity... The output can lock the centrifugal torque at a safe boundary while maintaining the aircraft's intended yaw direction (without reversing), achieving ultimate protection of 'no loss of direction and no overturning'.

[0106] Furthermore, in some embodiments of the present invention, in step S4, the PID control operation includes proportional control operation, integral control operation and derivative control operation.

[0107] Therefore, by coordinating the three PID parameters, the UAV can still lock the front wheel angle within the anti-overturning safety range under crosswind or uneven runway conditions, reducing the overturning probability by another order of magnitude. The PID operation is clearly decomposed into three terms: P (proportional control), I (integral control), and D (derivative control), which not only provides an accurate mathematical model but also achieves high-precision, high-stability, and high-robust front wheel closed-loop control.

[0108] Furthermore, in some embodiments of the present invention, in step S5, the front wheel actuation mechanism includes a servo motor or a motor. The servo motor or motor adjusts the output angle of the servo motor or motor according to the received PWM signal from the flight control module. The output angle of the servo motor or motor is transmitted to the front wheel steering mechanism through a mechanical transmission mechanism to realize the deflection of the front wheel.

[0109] It should be explained that the front wheel actuation mechanism is an electromechanical integrated device that converts the "front wheel control angle" command (electrical signal) output by the flight control system into the actual deflection angle of the front wheel during the taxiing phase of a fixed-wing UAV.

[0110] The power source of the front wheel actuator is a servo motor or electric motor. As the execution terminal of the "front wheel actuator", it converts the electrical signal output by the PID controller into mechanical angular displacement in real time, thereby accurately deflecting the physical front wheel to the target angle after the amplitude is limited.

[0111] Corresponding to the method provided in this application, this application also proposes a front wheel limiting device for preventing rollover during gliding of a fixed-wing unmanned aerial vehicle. Figure 3 The diagram schematically illustrates the structure of a fixed-wing UAV gliding anti-tipping front wheel limiting device 100 according to an embodiment of this application. The fixed-wing UAV gliding anti-tipping front wheel limiting device 100 includes a first calculation module 110, a second calculation module 120, a comparison and determination module 130, a control parameter adjustment module 140, and a yaw angle control module 150, wherein:

[0112] The first calculation module 110 is used for calculation based on gliding speed. v * Crosswind speed v side runway centerline deviation e and drone attitude angle i Calculate the front wheel deflection angle d ;

[0113] The second calculation module 120 is used to calculate the maximum front wheel deflection angle based on the fact that the anti-overturning moment of the UAV must balance the centrifugal moment. ;

[0114] The comparison and determination module 130 is used to determine the front wheel deflection angle. d and maximum front wheel deflection angle The size determines the front wheel control angle. ;

[0115] The control parameter adjustment module 140 is used to adjust the front wheel control angle based on the input to the PID controller. So that the PID controller can adjust according to the front wheel control angle. Perform PID control calculations;

[0116] The yaw angle control module 150 is used by the PID controller to control the flight control module to adjust the UAV's front wheel actuator to the front wheel control angle. .

[0117] The fixed-wing UAV gliding anti-tipping front wheel limiting device 100 proposed in this application uses the five modules of "perception-constraint-decision-execution-feedback" to lock the front wheel deflection angle in real time within the anti-tipping safety domain during the high-speed gliding phase. While maintaining centimeter-level trajectory accuracy, it reduces the probability of tipping over by two orders of magnitude, achieving safety, economy, and versatility.

[0118] Optional, such as Figure 4 As shown, this application embodiment also provides a fixed-wing unmanned aerial vehicle (UAV) 200, which includes the fixed-wing UAV gliding anti-tipping front wheel limiting device 100, processor 300, and memory 400 described above. The program or instructions stored in the memory 400 and executable on the processor 300 implement the various processes of the fixed-wing UAV gliding anti-tipping front wheel limiting method embodiment described above when the program or instructions are executed by the processor 300, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0119] The fixed-wing UAV 200 in this embodiment may also include a server, other computing devices, or a cloud server. Figure 7 The diagram shows the hardware structure of a fixed-wing drone 200 according to an embodiment of this application. The fixed-wing drone 200 may include a processor 300 and a memory 400 storing computer program instructions. When the processor 300 executes the computer program instructions, it implements the process or function of any of the methods described above.

[0120] Specifically, processor 300 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application. Memory 400 may include a large-capacity memory for data or instructions.

[0121] For example, memory 400 may be at least one of the following: hard disk drive (HDD), read-only memory (ROM), random access memory (RAM), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, universal serial bus (USB) drive, or other physical / tangible memory storage device.

[0122] For example, memory 400 may include removable or non-removable (or fixed) media. Furthermore, memory 400 may be internal or external to the integrated gateway disaster recovery device. Memory 400 may be non-volatile solid-state memory. In other words, memory 400 typically includes a tangible (non-transitory) computer-readable storage medium (such as a memory device) encoded with computer-executable instructions, and when the software is executed (e.g., by one or more processors), it can perform the operations described in the methods of the embodiments of this application. Processor 300 implements the flow or function of any of the methods in the above embodiments by reading and executing the computer program instructions stored in memory 400.

[0123] In one example Figure 4The fixed-wing UAV 200 shown may also include a communication interface 500 and a bus 600. The processor 300, memory 400, and communication interface 500 are connected via the bus 600 and communicate with each other. The communication interface 500 is mainly used to realize communication between the various modules, devices, units, and / or equipment in this embodiment. The bus 600 includes hardware, software, or both, and can couple the components of the online data traffic billing device together. For example, the bus may include at least one of the following: Accelerated Graphics Port (AGP) or other graphics bus, Enhanced Industry Standard Architecture (EISA) bus, Front Side Bus (FSB), HyperTransport (HT) Interconnect, Industry Standard Architecture (ISA) bus, Infinite Bandwidth Interconnect, Low Pin Count (LPC) bus, memory bus, Microchannel Architecture (MCA) bus, Peripheral Component Interconnect (PCI) bus, PCI-Express (PCI-X) bus, Serial Advanced Technology Attachment (SATA) bus, Video Electronics Standards Association Local (VLB) bus, or other suitable buses. The bus 600 may include one or more buses. Although specific buses are described or illustrated in the embodiments of this application, any suitable bus or interconnection method may be considered in the embodiments of this application.

[0124] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described fixed-wing UAV gliding anti-tipping front wheel limiting method embodiment and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0125] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0126] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described fixed-wing UAV gliding anti-tipping front wheel limiting method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0127] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0128] This application also provides a computer program product, which includes at least one computer program. When the computer program is loaded and executed by a processor, it implements the various processes of the above-described fixed-wing UAV gliding anti-tipping front wheel limiting method embodiment and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0129] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0130] To verify the aforementioned method for limiting the front wheel amplitude during gliding anti-tipping of fixed-wing UAVs, the following experiment is conducted using a large fixed-wing UAV as an example:

[0131] Based on the overall aircraft characteristic parameters, when the UAV's gliding speed is 5m / s, the maximum limiting angle of the front wheel is 57° according to formula (8). Similarly, the angle limits at different speeds can be obtained as follows: Figure 5 As shown.

[0132] After more than 40 high-speed taxiing tests of the large fixed-wing UAV, the above-mentioned anti-tipping front wheel limiting method has been verified to be safe and reliable, effectively preventing the occurrence of fixed-wing UAV tipping incidents and greatly improving the correction efficiency.

[0133] like Figure 6 , Figure 7 The diagram shows a comparison of the drone's taxiing speed, front wheel angle, and lateral deviation distance from the center of the runway before and after using the anti-tipping front wheel limiting method.

[0134] Data comparison shows that under the same high-speed taxiing conditions, before adopting the anti-tipping front wheel limiting method, the UAV's lateral drift was nearly 3 meters, exhibiting a divergent pattern; after adopting the anti-tipping front wheel limiting method, the lateral drift was almost 0 meters, showing a near-zero pattern. This real-world taxiing test data proves the effectiveness of the anti-tipping front wheel limiting method.

[0135] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A method for limiting the front wheel amplitude to prevent rollover during gliding of a fixed-wing unmanned aerial vehicle, characterized in that, The limiting method includes: Step S1: Based on gliding speed v* Crosswind speed v side runway centerline deviation e and drone attitude angle θ Calculate the front wheel deflection angle δ ; Specifically, it includes: Step S 11 The drone's gliding speed is obtained in real time via a pitot tube mounted on the leading edge of the nose. v * Crosswind speed is obtained in real time by a wind speed sensor installed on the top of the drone fuselage. v side The deviation between the UAV and the runway centerline is calculated in real time by a fiber-optic integrated navigation device in real-time dynamic differential positioning and navigation mode. e The attitude angle of the drone is obtained in real time by a fiber optic gyroscope installed on the drone. θ ; Step S 12 According to the stated gliding speed v* Crosswind speed v side runway centerline deviation e and drone attitude angle θ Determine the gain adjustment value; Step S 13 The proportional gain, integral gain, and derivative gain of the PID controller are adjusted using the aforementioned gain adjustment value. Step S 14 The front wheel deflection angle is calculated using the output formula of the PID controller. δ ; Step S2: Based on the fact that the anti-tipping moment of the UAV must balance the magnitude of the centrifugal moment, calculate the maximum front wheel deflection angle. ; The maximum front wheel deflection angle The calculation expression is: in, It's the drone's gravity. ρ air density, v For the drone's flight speed, S For wing area, The lift coefficient, a This refers to the distance between the left and right main landing gears. b This refers to the distance between the drone's nose landing gear and main landing gear. Step S3: Based on the front wheel deflection angle δ and maximum front wheel deflection angle Determine the front wheel control angle ; Step S4: Input the front wheel control angle to the PID controller. So that the PID controller can adjust the front wheel control angle accordingly. Perform PID control calculations; Step S5: The PID controller controls the flight control module to adjust the UAV's front wheel actuator to the front wheel control angle. .

2. The method for limiting the front wheel width of a fixed-wing UAV to prevent tipping during gliding, as described in claim 1, is characterized in that... In step S 14 The output formula of the PID controller is as follows: in, δ It's the front wheel deflection angle. It is proportional gain. It is integral gain. It is the differential gain.

3. The method for limiting the front wheel width of a fixed-wing UAV during gliding anti-tipping as described in claim 1, characterized in that, In step S3, based on the front wheel deflection angle δ and maximum front wheel deflection angle Determine the front wheel control angle , specifically including: Current wheel deflection angle δ Not greater than the maximum front wheel deflection angle At that time, output the front wheel control angle. equal to the front wheel deflection angle δ ; Current wheel deflection angle δ Greater than the maximum front wheel deflection angle At that time, output the front wheel control angle. Equal to the front wheel deflection angle δ Maximum front wheel deflection angle of the same polarity .

4. The method for limiting the front wheel width of a fixed-wing UAV to prevent tipping during gliding, as described in claim 1, is characterized in that... In step S4, the PID control operation includes proportional control operation, integral control operation and derivative control operation.

5. The method for limiting the front wheel width of a fixed-wing UAV to prevent tipping during gliding, as described in claim 1, is characterized in that... In step S5, the front wheel actuation mechanism includes a servo motor or a motor. The servo motor or motor adjusts its output angle according to the PWM signal received from the flight control module. The output angle of the servo motor or motor is transmitted to the front wheel steering mechanism through a mechanical transmission mechanism to achieve the deflection of the front wheel.

6. A gliding anti-tipping front wheel limiting device for a fixed-wing unmanned aerial vehicle, characterized in that, include: The first calculation module is used to calculate based on the gliding speed v. * Crosswind speed v side runway centerline deviation e and drone attitude angle θ Calculate the front wheel deflection angle δ ; specific include: Step S 11 The drone's gliding speed is obtained in real time via a pitot tube mounted on the leading edge of the nose. v * Crosswind speed is obtained in real time by a wind speed sensor installed on the top of the drone fuselage. v side The deviation between the UAV and the runway centerline is calculated in real time by a fiber-optic integrated navigation device in real-time dynamic differential positioning and navigation mode. e The attitude angle of the drone is obtained in real time by a fiber optic gyroscope installed on the drone. θ ; Step S 12 According to the stated gliding speed v* Crosswind speed v side runway centerline deviation e and drone attitude angle θ Determine the gain adjustment value; Step S 13 The proportional gain, integral gain, and derivative gain of the PID controller are adjusted using the aforementioned gain adjustment value. Step S 14 The front wheel deflection angle is calculated using the output formula of the PID controller. δ ; The second calculation module is used to calculate the maximum front wheel deflection angle based on the fact that the anti-overturning moment of the UAV must balance the centrifugal moment. ; The maximum front wheel deflection angle The calculation expression is: in, It's the drone's gravity. ρ air density, v For the drone's flight speed, S For wing area, The lift coefficient, a This refers to the distance between the left and right main landing gears. b This refers to the distance between the drone's nose landing gear and main landing gear. The comparison and determination module is used to determine the front wheel deflection angle δ and the maximum front wheel deflection angle based on the comparison and determination module. The size determines the front wheel control angle. ; The control parameter adjustment module is used to adjust the front wheel control angle based on the input to the PID controller. So that the PID controller can adjust the front wheel control angle accordingly. Perform PID control calculations; The deflection angle control module is used by the PID controller to control the flight control module to adjust the front wheel actuator of the UAV to the target front wheel deflection angle.

7. A fixed-wing unmanned aerial vehicle, characterized in that, include: The fixed-wing UAV anti-tipping front wheel limiting device as described in claim 6.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the fixed-wing UAV gliding anti-tipping front wheel limiting method as described in any one of claims 1-5.

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