Fixed-wing unmanned aerial vehicle sliding overturn-preventing front wheel amplitude limiting method and device and unmanned aerial vehicle

Abstract

The invention discloses a fixed-wing unmanned aerial vehicle sliding overturn-preventing front wheel amplitude limiting method and device and an unmanned aerial vehicle. The amplitude limiting method comprises the steps that the front wheel deflection angle delta is calculated; calculating the maximum front wheel deflection angle; determining a front wheel control angle according to the front wheel deflection angle delta and the maximum front wheel deflection angle; the front wheel control angle is input into a PID controller, so that the PID controller conducts PID control operation according to the front wheel control angle; and the PID controller controls the flight control module to adjust a front wheel actuating mechanism of the unmanned aerial vehicle to a front wheel control angle. Different front wheel angle limiting amplitudes are obtained according to different sliding speeds, the optimal correction performance of the unmanned aerial vehicle is matched on the premise that the unmanned aerial vehicle is prevented from overturning, and the correction efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles (UAVs), and in particular to a method and device for limiting the front wheels of a fixed-wing UAV for sliding and anti-rollover, and the UAV. Background Art

[0002] Fixed-wing drones are heavier-than-air unmanned aerial vehicles (UAVs) that take off and land by taxiing, using a propulsion system to generate thrust or pull and fixed wings to generate lift, allowing them to fly through the atmosphere. Due to their high efficiency and long range, fixed-wing UAVs are widely used in a variety of fields, including military reconnaissance, logistics and transportation, and environmental monitoring.

[0003] However, during the takeoff and landing phases, fixed-wing drones need to glide at high speed on the runway. This process is easily affected by various factors, such as crosswinds, uneven runway, operational errors, etc., which can cause the front wheels to oversteer, and then cause the body to overturn, causing damage to the drone or even casualties.

[0004] In existing technology, fixed-wing drones typically use front wheels, rudders, or a combination of both for lateral steering. For example, if a drone veers toward one side of the runway, the flight control computer directs the drone to the opposite side, thereby keeping it as close to the runway centerline as possible. During this steering process, the aircraft is subject to centrifugal force when turning, generating a certain overturning moment. To maintain the drone's balanced mode, the main wheels must actively generate an anti-overturning moment to offset the effect of this overturning moment.

[0005] For example, when a fixed-wing UAV is correcting its deviation, the conventional anti-rollover limiting strategy is as follows: based on past experience, a fixed front wheel steering angle limit is adopted, usually with a safety angle corresponding to the liftoff speed (e.g., 1°) 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 constant, ensuring the safety of the UAV's operation. However, the situation at different taxiing speeds is not considered, so the correction efficiency is low. When the UAV's speed does not reach the liftoff speed, the front wheel cannot steer for maximum efficiency correction due to the angle limit, resulting in the generation of side deviation of the UAV during taxiing.

[0006] Therefore, it is of great practical significance to study an effective front wheel limiting method for high-speed taxiing and anti-rollover of fixed-wing UAVs. Summary of the Invention

[0007] In view of this, the present invention aims to provide a method, device and drone for limiting the front wheels during taxiing to prevent overturning. By combining a mechanical limiting mechanism with an intelligent control strategy, the steering angle of the front wheels during high-speed taxiing can be effectively limited, thereby improving the stability and safety of the drone.

[0008] To solve the above problems, the first object of the present invention is to provide a method for limiting the front wheels of a fixed-wing UAV during taxiing and anti-rollover, the limiting method comprising: Step S1: Based on the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d ; Step S2: Calculate the maximum front wheel deflection angle based on the anti-overturning moment of the drone, which must balance the centrifugal moment. ; Step S3: According to the front wheel deflection angle d 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 controls the angle of the front wheel according to Perform PID control calculation; Step S5: The PID controller controls the flight control module to adjust the front wheel actuator of the UAV to the front wheel control angle .

[0009] Furthermore, in step S1, the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d , specifically including: Step S 11 :The glide speed v of the UAV is obtained in real time through the pitot tube installed on the leading edge of the nose, and the crosswind speed is obtained in real time through the wind speed sensor installed on the top of the UAV fuselage v side The deviation between the UAV and the runway centerline is calculated in real time by using the fiber optic combined navigation device in real-time dynamic differential positioning navigation mode. e , the UAV attitude angle is obtained in real time by installing a fiber optic gyroscope on the UAV i ; Step S 12 : According to the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle i determining a gain adjustment value; Step S13 : Adjusting the proportional gain, integral gain and differential gain of the PID controller by the gain adjustment value; Step S 14 :Calculate the front wheel deflection angle through the output formula of the PID controller d .

[0010] Further, in step S 14 Among them, the output formula of the PID controller is:

[0011] in, d is the front wheel deflection angle, is the proportional gain, is the integral gain, is the differential gain.

[0012] Furthermore, in step S2, the maximum front wheel deflection angle The calculation expression is:

[0013] in, It is the gravity of the drone, r is the air density, v is the flight speed of the drone, S is the wing area, is the lift coefficient, a is the distance between the left and right main landing gears, b is the distance between the front landing gear and the main landing gear of the UAV.

[0014] Further, in step S3, the front wheel deflection angle d and maximum front wheel deflection angle The size of the front wheel control angle is determined by , specifically including: Current wheel deflection angle d Not greater than the maximum front wheel deflection angle Output front wheel control angle Equal to the front wheel deflection angle d ; Current wheel deflection angle d Greater than the maximum front wheel deflection angle Output front wheel control angle Equal to the front wheel deflection angle d Maximum front wheel deflection angle with the same polarity .

[0015] Furthermore, in step S4, the PID control operation includes a proportional control operation, an integral control operation and a differential control operation.

[0016] Furthermore, in step S5, the front wheel actuating mechanism includes a servo or a motor, which adjusts the output angle of the servo or the motor according to the PWM signal received from the flight control module. The output angle of the servo or the motor is transmitted to the front wheel steering mechanism through a mechanical transmission mechanism to achieve deflection of the front wheel.

[0017] The second object of the present invention is to provide a front wheel limiting device for sliding and anti-overturning of a fixed-wing UAV, comprising: The first calculation module is used to calculate the glide speed based on the v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d ; The second calculation module is used to calculate the maximum front wheel deflection angle based on the anti-overturning moment of the drone must balance the centrifugal moment. ; A comparison and determination module is used to determine the front wheel deflection angle according to the d and the maximum front wheel deflection angle The size of the front wheel control angle is determined by ; A control parameter adjustment module is used to input the front wheel control angle into the PID controller , so that the PID controller controls the angle of the front wheel according to Perform PID control calculation; The deflection angle control module is used for the PID controller to control the flight control module to adjust the front wheel actuation mechanism of the UAV to the target front wheel deflection angle.

[0018] The third object of the present invention is to provide a fixed-wing UAV, comprising: the fixed-wing UAV sliding anti-overturning front wheel limiting device as described above.

[0019] The fourth object of the present invention is to provide a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the method for limiting the front wheel of a fixed-wing UAV for sliding and preventing overturning is implemented as described above.

[0020] Compared with the prior art, the present invention has significant advantages and beneficial effects, which are specifically reflected in the following aspects: The method for limiting the front wheel of a fixed-wing UAV during sliding to prevent overturning of the fixed-wing UAV includes the following steps: v, crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d ; Based on the fact that the anti-overturning moment of the drone must balance the centrifugal moment, calculate the maximum front wheel deflection angle ; According to 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 control the angle of the front wheel according to Perform PID control calculations; the PID controller controls the flight control module to adjust the drone's front wheel actuator to the front wheel control angle . Therefore, inputting the front wheel control angle into the PID controller and making it perform PID control calculations based on this angle is a key step in achieving precise control of the fixed-wing UAV during the high-speed gliding stage. By calculating the error between the target value and the actual value, the PID controller generates a control signal based on a combination of three control methods: proportional, integral, and differential, and drives the actuator to adjust the deflection angle of the front wheel. Through parameter adjustment, sensor calibration, fault detection and protection, as well as simulation and test verification, the stability and reliability of the control system can be ensured, the safety and stability of the UAV during the high-speed gliding stage can be improved, the occurrence of fixed-wing UAV overturning incidents can be effectively avoided, and the correction efficiency can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a schematic diagram of the overall process of the method for limiting the front wheel of a fixed-wing UAV for anti-rollover sliding according to an embodiment of the present invention; Figure 2 This is step S in the embodiment of the present invention. 100 Specific flow chart; Figure 3 2 is a schematic structural diagram of a front wheel limiter device for preventing rollover of a fixed-wing UAV during taxiing according to an embodiment of the present invention; Figure 4 2 is a schematic structural diagram of a fixed-wing UAV according to an embodiment of the present invention; Figure 5 Schematic diagram of the anti-rollover front wheel limit curve of a large fixed-wing UAV in an embodiment of the present invention; Figure 6 1 is a schematic diagram of a curve showing the taxiing speed of a UAV, the angle of the UAV's front wheels, and the lateral offset distance of the UAV from the middle of the runway before the anti-rollover front wheel limiting method is adopted in an embodiment of the present invention; Figure 73 is a schematic diagram of the curves of the UAV's gliding speed, the UAV's front wheel angle, and the UAV's lateral deviation from the middle of the runway after the anti-rollover front wheel limiting method is adopted in an embodiment of the present invention.

[0022] Description of reference numerals: 100 - fixed-wing UAV anti-rollover front wheel limiter; 110 - first calculation module; 120 - second calculation module; 130 - comparison and determination module; 140 - control parameter adjustment module; 150 - deflection angle control module; 200-fixed-wing drone; 300-processor; 400-memory. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] A fixed-wing UAV is a type of UAV with fixed wings whose outer wing sweep angle can be adjusted automatically or manually with speed.

[0025] During high-speed taxiing for takeoff and landing, fixed-wing drones may deviate from the runway centerline due to external factors such as crosswinds, posing a risk of skidding off the runway. For example, if a drone encounters a right-hand wind, it will deviate to the right side of the runway; if a drone encounters a left-hand wind, it will deviate to the left side of the runway. To ensure that the drone does not deviate from the runway under the influence of external factors and that its deviation from the runway centerline is within a certain range, a reasonable deviation correction strategy must be implemented to control the drone to approach the runway centerline. However, for high-speed taxiing drones, large turning angles may cause the aircraft to overturn and roll over. Therefore, different turning angle limits are used at different taxiing speeds to prevent the fixed-wing drone from overturning and improve the correction efficiency.

[0026] See also Figure 1 As shown, an embodiment of the present invention provides a method for limiting the front wheels of a fixed-wing UAV during high-speed gliding and anti-rollover, the limiting method comprising: Step S1: Based on the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d ; In this step, the sliding speed v It is an important parameter for calculating the front wheel deflection angle, because it directly affects the steering response speed and the size of the steering angle; crosswind speed v side Front wheel deflection angle dThe effect of the crosswind is essentially a "course correction compensation" relationship. The stronger the crosswind, the greater the required front wheel deflection angle, otherwise the drone will be blown off the runway centerline. In order to offset the deviation of the drone caused by the crosswind, the front wheel must generate a reverse deflection angle in advance to form the nose pointing correction and lateral force balance; when the drone is gliding at high speed, if there is a centerline deviation e , trajectory correction control is required.

[0027] Step S2: Calculate the maximum front wheel deflection angle based on the anti-overturning moment of the drone, which must balance the centrifugal moment. ; In this step, under the "no overturning" constraint, the steering process in high-speed sliding is simplified into a "side slip-roll" two-degree-of-freedom rigid body model, and the anti-overturning moment is set to ≥ the centrifugal moment, so that the critical maximum front wheel deflection angle can be solved. .

[0028] Step S3: According to the front wheel deflection angle d and maximum front wheel deflection angle , determine the front wheel control angle ; In this step, a front wheel control angle that is both safe and capable of tracking the target is given between the calculated "theoretical front wheel deflection angle" (given by upper-level algorithms such as trajectory tracking and sidewind compensation) and the "anti-rollover upper limit" (obtained in step S2). .

[0029] Step S4: Input the front wheel control angle to the PID controller , so that the PID controller can control the angle of the front wheel according to Perform PID control calculation; In this step, the front wheel control angle is input to the PID controller in real time. , further reducing the runway centerline error during the high-speed taxiing phase, thereby reducing the rollover probability by another order of magnitude.

[0030] Step S5: The PID controller controls the flight control module to adjust the front wheel actuator of the UAV to the front wheel control angle .

[0031] Therefore, inputting the front wheel control angle into the PID controller and performing PID control calculations based on this angle is a key step in achieving precise control of fixed-wing UAVs during high-speed taxiing. By calculating the error between the target and actual values, the PID controller generates a control signal based on a combination of proportional, integral, and differential control methods to drive the actuator to adjust the front wheel's 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 taxiing.

[0032] For further information, see Figure 2 As shown, in some embodiments of the present invention, in step S1, the sliding speed is based on v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d , specifically including: Step S 11 :The taxiing speed of the front wheel is obtained in real time through the pitot tube installed on the leading edge of the nose v , the wind speed sensor installed on the top of the drone fuselage obtains the crosswind speed in real time v side The optical fiber integrated navigation device in the real-time dynamic differential positioning RTK (Real-Time Kinematic) navigation mode calculates the deviation between the UAV and the runway centerline in real time. e , the UAV attitude angle is obtained in real time by installing a fiber optic gyroscope on the UAV i ; In this step, sensors (such as speed sensors, wind speed sensors, fiber optic integrated navigation equipment, fiber optic gyroscopes, etc.) are used to monitor the UAV's glide 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 equipment based on an inertial measurement unit (IMU). The measurement or estimation of crosswind speed needs to consider the direction and magnitude of the crosswind, because the crosswind will cause a lateral offset to the UAV's glide trajectory. The runway centerline deviation is used to keep the UAV within the runway safety zone at all times during the high-speed glide phase to prevent it from deviating from the runway or overturning. Changes in the UAV's attitude angle will cause an instantaneous change in the vertical distance h from the "center of gravity to the ground", which in turn affects the calculation of the anti-overturning moment in step S2, preventing overestimation or underestimation of the anti-overturning capability due to tilting the head up / down.

[0033] Step S 12 :According to the sliding speed v , crosswind speed v side , runway centerline deviatione and the drone's attitude angle i determining a gain adjustment value; In this step, during the high-speed gliding phase of the fixed-wing UAV, the v 、 v side 、 e 、 i The four real-time quantities calculate the "gain adjustment value" online to make the PID controller balance between "trajectory accuracy" and "anti-overturning safety", ensuring that the centrifugal torque is always lower than the anti-overturning limit, and achieving optimal trajectory control under the premise of zero overturning.

[0034] Step S 13 : Adjusting the proportional gain, integral gain and differential gain of the PID controller by the gain adjustment value; 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 under the premise of zero rollover.

[0035] Step S 14 :Calculate the front wheel deflection angle through the output formula of the PID controller d .

[0036] Furthermore, in some embodiments of the present invention, in step S 14 Among them, the output formula of the PID controller is:

[0037] in, d is the front wheel deflection angle; is the proportional gain, which determines the instantaneous correction force, and the unit is (° / °) or (μs / °); is the integral gain, used to eliminate steady-state error, unit (° / ·s) or (μs / ·s); is the differential gain, used to suppress overshoot and oscillation, with the unit being (·s / °) or (μs·s / °); e(t) is the error signal, that is, the difference between the expected value and the actual value.

[0038] It should be noted that the PID controller is a common feedback controller that is widely used in various control systems, including the flight control system of drones. Its main function is to adjust the system output to the desired target value through a combination of three control methods: proportional (P), integral (I) and differential (D). The parameters of the PID controller ( 、 、 ) need to be adjusted and optimized based on the specific drone model and actual operating environment. Parameter adjustment can be performed through a combination of testing and simulation to ensure the stability and responsiveness of the control system.

[0039] Furthermore, in some embodiments of the present invention, in step S2, the maximum front wheel deflection angle The calculation expression is:

[0040] in, It is the gravity of the drone, r is the air density, v is the flight speed of the drone, S is the wing area, is the lift coefficient, a is the distance between the left and right main landing gears, b is the distance between the front landing gear and the main landing gear of the UAV.

[0041] Specifically, when a fixed-wing UAV turns, it is acted upon by centrifugal force, the point of action of which is located at the center of gravity of the UAV. The centrifugal force calculation formula for the fixed-wing UAV is: (1) Where: F c is the centrifugal force, m For drone quality, v is the taxiing speed of the UAV, R is the turning radius of the drone.

[0042] Due to the turning radius of fixed-wing drones R Front wheel turning angle The relationship between them is: (2) Where: R is the turning radius of the drone, is the front wheel turning angle, b is the distance between the front landing gear and the main landing gear of the UAV.

[0043] Combining formulas (1) and (2), the centrifugal force can be expressed as: (3) Therefore, the overturning moment caused by centrifugal force is: (4) Where, h is the height of the center of gravity of the UAV acting on the overturning moment; To prevent the UAV from rolling over, the anti-overturning moment must balance the centrifugal moment. The anti-overturning moment is generated by the main wheels. Therefore, the magnitude of the anti-overturning moment is: (5) Where, a is the distance between the left and right main landing gear.

[0044] Due to the payload W eff The lift caused by the gliding speed L Reduce the payload of the drone W eff The size is: (6) Where, r is the air density, v is the flight speed of the drone, S is the wing area, is the lift coefficient.

[0045] To prevent the main wheel on one side from lifting, the anti-overturning moment must be greater than or equal to the rolling moment: (7) Arranging the above formula, we can get the maximum front wheel deflection angle The calculation expression is: (8) 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 taxiing speeds to match the best correction performance of the UAV while preventing the UAV from overturning.

[0046] Furthermore, in some embodiments of the present invention, in step S3, the front wheel deflection angle d and maximum front wheel deflection angle The size of the front wheel control angle is determined by , specifically including: Current wheel deflection angle d Not greater than the maximum front wheel deflection angle Output front wheel control angle Equal to the front wheel deflection angle d ; Current wheel deflection angle d Greater than the maximum front wheel deflection angle Output front wheel control angle Equal to the front wheel deflection angle d Maximum front wheel deflection angle with the same polarity .

[0047] Therefore, when the centrifugal moment has not yet reached the anti-rollover limit, the system is in a safe zone, so there is no need for any clipping, and the desired angle can be directly output as the control angle, which not only ensures the trajectory accuracy but also avoids unnecessary performance loss; when the centrifugal moment has exceeded the anti-rollover limit, continuing to increase the angle will inevitably lead to overturning; using the same polarity Output can lock the centrifugal torque within the safety boundary while maintaining the aircraft's yaw direction intention (not reverse), achieving the ultimate protection of "no loss of direction and no overturning".

[0048] Furthermore, in some embodiments of the present invention, in step S4, the PID control operation includes a proportional control operation, an integral control operation, and a differential control operation.

[0049] Therefore, through the coordination of the three PID terms, the drone can still lock the front wheel angle in the anti-rollover safety zone under crosswind or uneven runway conditions, reducing the rollover probability by another order of magnitude; the PID operation is clearly split into three terms: P (proportional control), I (integral control), and D (differential control), which not only provides an accurate mathematical model, but also realizes high-precision, high-stability, and high-robust front wheel closed-loop control.

[0050] Furthermore, in some embodiments of the present invention, in step S5, the front wheel actuating mechanism includes a servo or a motor, which adjusts the output angle of the servo or the motor according to the PWM signal received from the flight control module, and the output angle of the servo or the motor is transmitted to the front wheel steering mechanism through a mechanical transmission mechanism to achieve deflection of the front wheel.

[0051] It should be explained that the front wheel actuator mechanism is a mechatronic 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 the fixed-wing UAV.

[0052] The power source of the front wheel actuation mechanism is a servo or motor, which serves as the execution terminal of the "front wheel actuation mechanism". 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 limiting.

[0053] Corresponding to the method provided in this application, this application also proposes a front wheel limiter device for sliding and preventing rollover of fixed-wing UAV. Figure 3 The structure of a fixed-wing UAV anti-rollover front wheel limiting device 100 for sliding is schematically shown in an embodiment of the present application. The fixed-wing UAV anti-rollover 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 deflection angle control module 150, wherein: The first calculation module 110 is used to calculate the glide speed based on the v, crosswind speed v side , runway centerline deviation e and the drone's attitude angle i , calculate the front wheel deflection angle d ; 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 drone must balance the centrifugal moment. ; The comparison and determination module 130 is used to determine the front wheel deflection angle according to the d and maximum front wheel deflection angle The size of the front wheel control angle is determined by ; The control parameter adjustment module 140 is used to input the front wheel control angle into the PID controller based on , so that the PID controller can control the angle of the front wheel according to Perform PID control calculation; The deflection angle control module 150 is used for the PID controller to control the flight control module to adjust the front wheel actuator of the UAV to the front wheel control angle .

[0054] By using a fixed-wing UAV anti-rollover front wheel limiting device 100 proposed in an embodiment of the present application, the five modules of "perception-constraint-decision-execution-feedback" work together to lock the front wheel deflection angle in the high-speed gliding stage within the anti-rollover safety domain in real time. While maintaining centimeter-level trajectory accuracy, the rollover probability is reduced by two orders of magnitude, achieving safety, economy, and versatility.

[0055] Optional, such as Figure 4 As shown, the embodiment of the present application also provides a fixed-wing UAV 200, which includes the above-mentioned fixed-wing UAV sliding anti-rollover front wheel limiting device 100, a processor 300 and a memory 400, and a program or instruction stored in the memory 400 and executable on the processor 300. When the program or instruction is executed by the processor 300, each process of the above-mentioned fixed-wing UAV sliding anti-rollover front wheel limiting method embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0056] The fixed-wing UAV 200 in the embodiment of the present application may further include a server, other computing devices, and a cloud server. Figure 7 A hardware structure diagram of a fixed-wing UAV 200 according to an embodiment of the present application is shown. The fixed-wing UAV 200 may include a processor 300 and a memory 400 storing computer program instructions. When the processor 300 executes the computer program instructions, the process or function of any of the above-mentioned embodiments is implemented.

[0057] Specifically, the processor 300 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application. The memory 400 may include a large-capacity memory for data or instructions.

[0058] For example, the memory 400 may be at least one of the following: a hard disk drive (HDD), a read-only memory (ROM), a random access memory (RAM), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, a universal serial bus (USB) drive, or other physical / tangible memory storage devices.

[0059] For another example, the memory 400 may include removable or non-removable (or fixed) media. For another example, the memory 400 may be inside or outside the integrated gateway disaster recovery device. The memory 400 may be a non-volatile solid-state memory. In other words, the 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 (such as by one or more processors), the operations described in the method of the embodiment of the present application can be performed. The processor 300 implements the process or function of any of the methods in the above embodiments by reading and executing the computer program instructions stored in the memory 400.

[0060] In one example, Figure 4The fixed-wing drone 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 bus 600 and communicate with each other. The communication interface 500 is primarily used to facilitate communication between the various modules, devices, units, and / or equipment in the embodiments of this application. Bus 600, which may comprise hardware, software, or both, couples the components of the online data traffic metering device. For example, the bus may include at least one of the following: an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industrial Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses. Bus 600 may include one or more buses. Although the embodiments of the present application describe or illustrate a specific bus, the embodiments of the present application may consider any suitable bus or interconnection method.

[0061] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of the above-mentioned fixed-wing UAV sliding anti-rollover front wheel limiting method embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0062] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk.

[0063] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned fixed-wing UAV sliding anti-rollover front wheel limiting method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0064] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0065] An embodiment of the present 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-mentioned fixed-wing UAV sliding anti-rollover front wheel limiting method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0066] Through the description of the above embodiments, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course 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 the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0067] To verify the above-mentioned front wheel limit method for anti-rollover of fixed-wing UAV during taxiing, the following experimental verification is conducted on a large fixed-wing UAV: Combined with the characteristic parameters of the entire aircraft, when the UAV glides at a speed of 5m / s, the maximum limit 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 shown.

[0068] After more than 40 high-speed taxiing tests of this large fixed-wing UAV, it was verified that the above-mentioned anti-rollover front wheel limiting method is safe and reliable, effectively avoiding the occurrence of rollover incidents of fixed-wing UAVs and greatly improving the correction efficiency.

[0069] like Figure 6 、 Figure 7 As shown, a schematic diagram of the comparative data results of the UAV's taxiing speed, the UAV's front wheel angle and the UAV's lateral deviation from the middle of the runway before and after using the anti-rollover front wheel limiting method.

[0070] Comparing the data reveals that, under the same high-speed taxiing conditions, before the anti-rollover front wheel clipping method was implemented, the UAV's lateral deviation was nearly 3 meters, exhibiting a diverging pattern. After the anti-rollover front wheel clipping method was implemented, the lateral deviation was nearly 0 meters, exhibiting a closing pattern. This real-world taxiing test data demonstrates the effectiveness of the anti-rollover front wheel clipping method.

[0071] Although the present invention is disclosed as above, the scope of protection disclosed by the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for limiting the front wheel of a fixed-wing UAV during taxiing to prevent overturning, characterized in that: The limiting method includes: Step S1: Based on the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle θ , calculate the front wheel deflection angle δ ; Step S2: Calculate the maximum front wheel deflection angle based on the anti-overturning moment of the drone, which must balance the centrifugal moment. ; Step S3: According to 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 controls the angle of the front wheel according to Perform PID control calculation; Step S5: The PID controller controls the flight control module to adjust the front wheel actuator of the UAV to the front wheel control angle .

2. The method for limiting the front wheel of a fixed-wing UAV during taxiing and anti-rollover according to claim 1 is characterized in that: In step S1, the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle θ , calculate the front wheel deflection angle δ , specifically including: Step S 11 :The glide speed v of the UAV is obtained in real time through the pitot tube installed on the leading edge of the nose, and the crosswind speed is obtained in real time through the wind speed sensor installed on the top of the UAV fuselage v side The deviation between the UAV and the runway centerline is calculated in real time by using the fiber optic combined navigation device in real-time dynamic differential positioning navigation mode. e , the UAV attitude angle is obtained in real time by the fiber optic gyroscope installed on the UAV θ ; Step S 12 :According to the sliding speed v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle θ determining a gain adjustment value; Step S 13 : Adjusting the proportional gain, integral gain and differential gain of the PID controller by the gain adjustment value; Step S 14 :Calculate the front wheel deflection angle through the output formula of the PID controller δ .

3. The method for limiting the front wheel of a fixed-wing UAV during taxiing and anti-rollover according to claim 1 is characterized in that: In step S 14 Among them, the output formula of the PID controller is: in, δ is the front wheel deflection angle, is the proportional gain, is the integral gain, is the differential gain.

4. The method for limiting the front wheel of a fixed-wing UAV during taxiing to prevent overturning according to claim 1 is characterized in that: In step S2, the maximum front wheel deflection angle The calculation expression is: in, It is the gravity of the drone, ρ is the air density, v is the flight speed of the drone, S is the wing area, is the lift coefficient, a is the distance between the left and right main landing gears, b is the distance between the front landing gear and the main landing gear of the UAV.

5. The method for limiting the front wheel of a fixed-wing UAV during taxiing and anti-rollover according to claim 1 is characterized in that: In step S3, according to 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 Output 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 Output front wheel control angle Equal to the front wheel deflection angle δ Maximum front wheel deflection angle with the same polarity .

6. The method for limiting the front wheel of a fixed-wing UAV during taxiing and anti-rollover according to claim 1, characterized in that: In step S4, the PID control operation includes a proportional control operation, an integral control operation, and a differential control operation.

7. The method for limiting the front wheel of a fixed-wing UAV during taxiing and anti-rollover according to claim 1, characterized in that: In step S5, the front wheel actuating mechanism includes a servo or a motor, which adjusts the output angle of the servo or the motor according to the PWM signal received from the flight control module. The output angle of the servo or the motor is transmitted to the front wheel steering mechanism through a mechanical transmission mechanism to achieve deflection of the front wheel.

8. A front wheel limiter device for sliding and anti-overturning of fixed-wing UAV, characterized in that: include: The first calculation module is used to calculate the glide speed based on the v , crosswind speed v side , runway centerline deviation e and the drone's attitude angle θ , calculate the front wheel deflection angle δ ; The second calculation module is used to calculate the maximum front wheel deflection angle based on the anti-overturning moment of the drone must balance the centrifugal moment. ; A comparison and determination module is configured to determine the maximum front wheel deflection angle according to the front wheel deflection angle δ and the maximum front wheel deflection angle. The size of the front wheel control angle is determined by ; A control parameter adjustment module is used to input the front wheel control angle into the PID controller , so that the PID controller controls the angle of the front wheel according to Perform PID control calculation; The deflection angle control module is used for the PID controller to control the flight control module to adjust the front wheel actuation mechanism of the UAV to the target front wheel deflection angle.

9. A fixed-wing UAV, characterized in that: include: The fixed-wing UAV anti-rollover front wheel limiting device as claimed in claim 8.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by the processor, the method for limiting the front wheel of the fixed-wing unmanned aerial vehicle for sliding and anti-rollover according to any one of claims 1 to 7 is implemented.

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