CN117963200A - High-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support and control method - Google Patents

Abstract

The invention discloses a high-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support and a control method, wherein a driving device is a disc-type permanent magnet motor, a motor permanent magnet is arranged at the bottom of a motor turntable and is axially arranged at intervals with an electronic stator; the bottom of the disc type permanent magnet motor is provided with a passive permanent magnet; the axial magnetic suspension structure is arranged below the disc type permanent magnet motor and comprises a magnetic suspension bearing turntable and a magnetic suspension bearing stator; the upper surface of the magnetic suspension bearing turntable is provided with another passive permanent magnet and forms a repulsive magnetic suspension structure with the passive permanent magnet at the bottom of the disc permanent magnet motor; the magnetic suspension bearing rotor sheet is arranged below the magnetic suspension bearing turntable, and the motor rotating shaft passes through the magnetic suspension bearing turntable and the magnetic suspension bearing stator inner ring; and a duct, which is a cylindrical enclosing rotor device from the periphery. The stealth performance of the unmanned aerial vehicle can be effectively improved, noise is reduced, the load capacity is increased, and the safety of the unmanned aerial vehicle body is improved.

Description

High-speed stealth UAV based on axial magnetic support and control method

Technical Field

The present application relates to the technical field of unmanned aerial vehicles, and in particular to a high-speed stealth unmanned aerial vehicle and an attitude control method based on axial magnetic support.

Background technique

Drones have the advantages of strong maneuverability, low cost, simple structure, easy control, and reusability. They are now increasingly used in military and civilian fields.

Drones can hover in the air and have good maneuverability, which is very helpful for performing operational tasks. However, for drones with stealth and load requirements, the flight stealth and load functions of existing drone equipment are poor. When flying in hills and forests, their blades are easily damaged by collisions, which affects the service life of the drone.

In order to increase the flight time and payload of drones with stealth and payload requirements, it is necessary to design a new drone structure with light weight, high efficiency and low noise.

Summary of the invention

The purpose of this application is to provide a high-speed stealth UAV attitude control method based on axial magnetic support, which can effectively improve the stealth performance of the UAV, reduce noise, increase load capacity, and improve the fuselage safety of the UAV.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A high-speed stealth UAV based on axial magnetic support, characterized by comprising:

The rotor device is composed of two blades stacked at an angle up and down on the drive device;

The driving device is a disc-type permanent magnet motor, the motor permanent magnet is arranged at the bottom of the motor turntable and is axially spaced from the electronic stator; a passive permanent magnet is arranged at the bottom of the disc-type permanent magnet motor;

The axial magnetic suspension structure is arranged below the disk-type permanent magnet motor, and includes a magnetic suspension bearing turntable and a magnetic suspension bearing stator; the upper surface of the magnetic suspension bearing turntable is provided with another passive permanent magnet and forms a repelling magnetic suspension structure with the passive permanent magnet at the bottom of the disk-type permanent magnet motor; the magnetic suspension bearing rotor sheet is installed below the magnetic suspension bearing turntable, and the motor shaft passes through the magnetic suspension bearing turntable and the inner ring of the magnetic suspension bearing stator;

The flight control device is arranged below the axial magnetic suspension structure, and mainly includes a steering gear and a plurality of radial rudder blades connected below the steering gear. The deflection angle of the rudder blades is set to be adjusted according to the steering gear to control the navigation attitude control of the UAV;

The duct encloses the rotor device in a cylindrical shape from the outside, and support devices are arranged on the bottom and inner wall of the duct to achieve radial and axial support.

In the above technical solution, the axial gap between the magnetic bearing rotor sheet and the magnetic bearing stator is 0.5 mm.

In the above technical solution, the wing device is composed of two two-blade propellers, and the two two-blade propellers are stacked on the disc motor turntable at an angle of 90 degrees from top to bottom.

In the above technical solution, the motor turntable is tightly connected to the motor shaft, and two mechanical bearings are used in the middle to rotatably support the motor stator.

In the above technical solution, the axial clearance between the motor rotor and the stator is 0.5mm-1mm.

In the above technical solution, the axial magnetic suspension structure and the driving device are provided with an intermediate component housing, and the duct and the intermediate component housing are radially fastened and connected by a supporting structure.

In the above technical solution, the axial magnetic suspension structure and the driving device are arranged for the intermediate component housing, and the duct is fastened to the intermediate component housing by means of a supporting structure.

In the above technical solution, the motor shaft passes through the magnetic bearing turntable and the inner ring of the magnetic bearing stator, passes through the intermediate component housing, and is connected to the rolling contact device to form a buffer structure, and an eddy current displacement sensor is arranged at the end of the motor shaft to detect displacement.

In the above technical solution, the end of the motor shaft is fixedly installed using a nut, wherein the lower end face of the nut and the base plate are spaced with balls to form an end face friction buffer structure, the base plate is fixed in the circular groove of the bottom shell, and the eddy current displacement sensor is installed at the center hole of the base plate.

In the above technical solution, the inner ring of the stator of the magnetic bearing is embedded with a permanent magnet ring.

In the above technical solution, the magnetic bearing stator is a magnetic bearing stator with a U-shaped cross-section, and the coil is arranged in the U-shaped groove.

A high-speed stealth UAV control method based on axial magnetic support, characterized by comprising the following steps:

S1: Get the initial reference roll angle of the drone Pitch angle θ, yaw angle ψ, the three angle parameters after attitude solution and the roll angle considered/> The pitch angle θ and the yaw angle ψ are compared, and the difference is coded and solved and processed by complementary filtering, and then input into the adaptive sliding film controller to output the attitude parameters;

S2: Adjust the steering gear deflection angle and motor speed according to the output attitude parameters;

S3: The adjusted steering gear deflection angle and motor speed are input into the RBF neural network for training;

S4: The steering gear deflection angle and motor speed parameters output after training re-enter the adaptive sliding membrane controller to obtain attitude parameters;

S5: repeat step S2. If the required control attitude is achieved, the adjusted steering gear deflection angle and motor speed are input into the UAV to perform a new attitude flight. If the required control attitude is not achieved, repeat steps S3 and S4.

S6: During the execution of the new attitude flight, the attitude reference system (AHRS) outputs the roll angle, pitch angle, and yaw angle of the drone;

S7: Perform attitude calculation based on the real-time roll angle, pitch angle, and yaw angle, compare the angle parameters of the three roll angles, pitch angles, and yaw angles after attitude calculation with the three attitude parameters of the UAV attitude reference, and perform adaptive control in a cycle.

In summary, the present invention mainly includes a ducted single-rotor UAV fuselage structure and a matching flight control system.

Rotor UAVs are driven by disc permanent magnet motors, which have the characteristics of high power torque density, high efficiency and compact structure, and are very suitable for high-performance applications, such as direct drive systems with high requirements for low noise and smooth torque. Its single stator-rotor structure is the simplest and is very suitable for the drive system of UAVs.

A rotor system consisting of two two-blade propellers is installed on the upper end of the motor turntable, and a hybrid axial magnetic bearing is installed on the lower end of the motor. The rotor shaft of the motor and the rotor of the axial magnetic bearing are an integrated structure. When the motor drives the rotor to rotate, the hybrid active magnetic bearing system is started at the same time to achieve axial suspension of the rotating device of the blade-motor turntable-shaft. During suspension, the friction loss and noise of the shaft are reduced, the rotation speed is increased, and the load-bearing capacity and stealth performance are increased.

The drone uses ducts as support, and the rotor's intermediate shell and duct are fastened with spokes, which can effectively reduce the weight of the fuselage. At the same time, the duct brings additional lift to the drone, which can more effectively protect the blades and reduce blade noise. Ducted drones add ducts to the outside of the drone, which wrap the drone's annular wings. The use of ducts will significantly improve the drone's pulling efficiency characteristics. Adding a ducted shell to the drone can increase the overall lift by about 10%, and the duct can protect the drone from collisions, while increasing safety and reducing noise, improving hovering efficiency. Its compact structure is very suitable for reconnaissance, patrol and other tasks.

The flight control system combines magnetic bearing control and conventional flight attitude control, and develops a flight control system based on radial basis function RBF neural network adaptive sliding film control. The magnetic bearing system is started at the beginning of the flight to stabilize the rotor axial suspension. The flight attitude actuator is the servo that controls the deflection angle of the rudder blade. The rudder blade angle is adjusted to achieve vertical take-off and landing, pitch, level flight and other attitude flights of the rotor. The axially suspended ducted rotor structure has low rotation friction, high speed, large load, low noise, and can greatly improve flight stealth and load-bearing performance.

There are many structural forms of propellers for drones. Two-blade propellers are more efficient and suitable for aircraft with higher requirements for speed and maneuverability. For disc motors with higher speed and lower torque in the drive system, using two two-blade propellers can improve the lift and operating efficiency of the drone system.

Magnetic levitation technology is a technology that uses magnetic force to overcome gravity to suspend an object. Among them, magnetic levitation bearing technology can greatly reduce the mechanical friction between the stator and the rotor and reduce energy consumption. Axial magnetic levitation bearings can stably suspend the turntable. Introducing magnetic levitation bearings into drones to stably suspend the shaft can greatly reduce friction loss and noise, increase rotation speed, and increase load capacity and flight time.

Compared with the prior art, the present invention has the following advantages:

1. Using magnetic bearing technology, the UAV is axially suspended when running, with high rotation speed, low noise, strong stealth performance and strong load capacity.

2. The propeller blade-motor turntable-shaft is a new structure that can be axially suspended. The disc permanent magnet motor is used as the drive. After the motor is started, it drives the motor turntable to rotate. The propeller blades accelerate the rotation to increase the lift, driving the propeller blade-motor turntable-shaft structure to float. The active magnetic suspension system is started, and the magnetic suspension bearing will stably suspend the turntable, so that the propeller blade-motor turntable-shaft structure remains in an axial suspension state.

At the same time, a ball bearing is used at the bottom of the shaft to reduce friction and increase the replaceability of parts.

3. Add a duct casing and connect and fasten it with spokes, which can reduce the weight of the whole machine and increase the overall lift of the fuselage and prevent blade collision.

4. The flight control system adopts radial basis neural network adaptive sliding film control, which can accelerate the training of numerical samples of flight attitude and deflection angle, enhance the robustness of the flight system, and ensure the stability of the UAV's flight attitude adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

FIG1 is a structural diagram (top view) of a high-speed stealth UAV based on axial magnetic support according to the present invention.

Fig. 2 is a cross-sectional view taken along the line B-B of Fig. 1 .

FIG3 is a structural diagram of a high-speed stealth UAV rotor device based on axial magnetic support according to the present invention.

FIG4 is a structural diagram (stereoscopic diagram) of a high-speed stealth UAV based on axial magnetic support according to the present invention.

FIG5 is a schematic diagram of the structure of a high-speed stealth UAV drive device based on axial magnetic support according to the present invention.

FIG. 6 is a schematic diagram of the structure of a magnetic suspension system matching FIG. 5 .

FIG. 7 is a simulation diagram of the axial self-suspension magnetic field of the hybrid magnetic bearing.

FIG8 is a simulation of the repulsive magnetic field of a permanent magnet performed for the present invention.

9 is a schematic diagram showing a reference attitude angle of a flight control system for a high-speed stealth UAV based on axial magnetic support according to the present invention.

FIG. 10 is a flow chart of an RBF network adaptive sliding membrane flight control algorithm implemented according to the present invention.

FIG. 11 is a motor speed-torque diagram designed according to Table 1.

FIG12 is a motor speed-power diagram designed according to Table 1.

FIG13 is a motor speed-current diagram designed according to Table 1.

FIG. 14 is a graph showing the input power curve corresponding to the increase in motor speed.

FIG. 15 is a graph showing the input current corresponding to the increase in motor speed.

FIG. 16 is a schematic diagram showing the direction of magnetic field lines of the magnetic circuit of the present invention.

FIG. 17 is a diagram showing the relationship between the magnetic field lines and the magnetic field strength of the permanent magnet of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition and explanation in the subsequent drawings.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

The features and performance of the present application are further described in detail below in conjunction with the embodiments.

Example 1

As shown in FIGS. 1-10 , the high-speed stealth UAV based on axial magnetic support implemented according to the present invention includes a rotor device, a drive device, an axial magnetic suspension structure, a flight control device, a duct 1, and a support device.

As shown in Fig. 1, 3-4, the rotor device is composed of two two-blade propellers 6, which are stacked at 90° on the disc motor turntable 20. The magnetic suspension system is divided into two parts, the first part is the passive permanent magnet 27 axial suspension support, and the second part is the hybrid axial active magnetic suspension bearing. The duct 1 and the intermediate component shell are fastened with spokes 7, and the support device is installed at the bottom of the duct 1 by the landing frame 4.

Ducted UAVs add ducts 1 to the outside of the UAV as a wrapping ring wing. The use of ducts will significantly improve the pulling efficiency characteristics of the UAV. Adding a ducted shell to the UAV can increase the overall lift by about 10%, and the duct can protect the UAV from collisions, while increasing safety and reducing noise, improving hovering efficiency. Its compact structure is very suitable for reconnaissance, patrol and other tasks.

More specifically, as shown in FIG5 , the drive device is a disk motor, and the motor permanent magnet 23 is arranged at the bottom of the motor turntable 20, and is arranged axially opposite to the electronic stator 19. The motor turntable 20 of the disk permanent magnet motor is connected to the rotating shaft 24 by screws, and two mechanical bearings 25 are used in the middle to prevent the motor turntable 20 from tilting and colliding with the motor stator, ensuring the radial stability of the motor rotor, and the turntable and stator are lightweight. The axial clearance between the motor turntable 20 (rotor) and the fixed motor stator 19 is adjustable, mainly relying on the hybrid active magnetic suspension system for adjustment, and the maximum axial clearance between the motor rotor and the stator is 1mm, mainly relying on the passive permanent magnet 27, magnetic suspension bearing turntable 28, bearing 25, and nut 16 installed on the rotating shaft 24, and cooperating with the motor housing 29 to limit the maximum clearance between the motor stator and the rotor, and relying on the bearing end cover 26 to prevent the motor turntable 20 from falling and colliding with the motor stator, protecting the minimum clearance between the motor rotor and the stator is 0.5mm.

Specifically, the passive permanent magnet 27 structure installed at the bottom of the motor housing 29 simultaneously limits the upward axial movement of the rotating shaft 24; a mechanical bearing is used at the end of the rotating shaft 24 to limit the radial runout of the end, and a nut 16 is used to fix the mounting component on the rotating shaft to prevent axial movement. A ball 11 is used at the bottom of the rotating shaft to limit the downward axial movement and reduce the friction of the nut end face.

The disc permanent magnet motor is used as the drive. After the motor is started, it drives the motor turntable to rotate. The blades rotate faster to increase lift, driving the blade-motor turntable-shaft structure to float. The active magnetic suspension system is started, and the magnetic suspension bearing will stably suspend the turntable, allowing the blade-motor turntable-shaft structure to maintain an axial suspension state.

As shown in Figures 1 and 6, the axial magnetic suspension structure consists of two parts. One part is a passive magnetic suspension bearing, which is composed of a pair of repelling magnetic suspension structures formed by the passive permanent magnet 27 at the bottom of the disc permanent magnet motor housing and the passive permanent magnet 27 in the magnetic suspension bearing turntable 28; the other part is an active hybrid magnetic suspension bearing, and the magnetic suspension bearing rotor sheet (rotor silicon steel sheet) 8 is installed at the lower end of the magnetic suspension bearing turntable 28, and its magnetic suspension bearing stator (stator silicon steel sheet) 17 is inlaid with a permanent magnet ring 10 in the inner ring to increase the magnetic field strength, and the axial gap between the magnetic suspension bearing rotor sheet 8 and the magnetic suspension bearing stator 17 is 0.5mm.

More specifically, the first part of the axial magnetic suspension structure is composed of two passive permanent magnets 27, wherein the upper magnetic ring is installed at the bottom of the motor housing 29, and the lower magnetic ring is installed at the upper end of the rotor turntable 28. The two magnetic rings repel each other axially to provide magnetic force for axial support; the second part is a hybrid axial active magnetic suspension bearing, which is composed of a U-shaped magnetic suspension bearing stator 17, a magnetic suspension bearing rotor sheet 8, a coil 9, and a permanent magnet ring 10. After the coil 9 is energized, the coil electromagnetic circuit is formed by the U-shaped magnetic suspension bearing stator 17 and the magnetic suspension bearing rotor sheet 8. The permanent magnet ring 10 is installed inside the U-shaped magnetic suspension bearing stator 17 to increase the electromagnetic strength of the inner end of the stator and improve the axial downward electromagnetic pulling force. At the same time, in the passive permanent magnet 27, the upper and lower permanent magnets repel each other, provide a downward axial force, and increase the magnetic field strength for the hybrid magnetic suspension bearing below.

The fuselage structure of a high-speed stealth UAV based on axial magnetic support is shown in Figures 1 and 4, and its features include: a ducted housing 1, a fixed aluminum alloy outer ring 2, a rudder blade rotating shaft 3, a landing frame 4, a rudder blade 5, a carbon fiber blade 6, a fastening spoke 7, a magnetic suspension bearing rotor sheet 8, a magnetic suspension bearing coil 9, a magnetic suspension bearing hybrid permanent magnet 10, a ball 11, an eddy current displacement sensor 12, a rudder blade fixing frame 13, a rudder blade mounting block 14, a ball bearing base plate 15, an M10 thin nut 16, a magnetic suspension bearing stator 17, a bottom shell 18, a motor stator 19, a motor turntable 20, a blade mounting plate 21, a blade fixing gasket 22, a motor permanent magnet 23, a motor shaft 24, a GB61800 bearing 25, a bearing end cover 26, a passive permanent magnet 27, a magnetic suspension bearing rotor turntable 28, and a motor housing 29.

The end of the motor shaft 24 is thread-locked with a nut 16, and its specific layout is shown in Figure 7. The components installed on the shaft 24 from top to bottom are: motor turntable 20, bearing end cover 26, GB61800 bearing 25, long bearing sleeve, magnetic suspension bearing rotor turntable 28, short bearing sleeve, GB61800 bearing 25, gasket, M10 thin nut 16. The lower end face of the M10 thin nut 16 is separated from the ball bottom plate 15 by a ball 11 to ensure that when the shaft falls, the end face friction is reduced when the nut rotates. The bottom plate 15 is fixed in the circular groove of the bottom shell 18, and the position sensor 12 is installed at the center hole position of the bottom plate to detect the axial displacement of the motor shaft 24. The mechanical bearing 25 close to the nut 16 cooperates with the bottom shell 18 to limit the radial runout of the end of the shaft 24.

The middle bottom shell 18 is connected to the outer duct 1 with spokes 7. The upper end of the bottom shell 18 is staggered with 16 spokes 7, and the lower end is staggered with 8 spokes 7. The spokes 7 pass through the holes in the outer ring of the bottom shell 18 and are staggered, similar to the spoke installation method of a bicycle, to ensure the horizontal stability of the middle rotating part. The structure is shown in Figure 9. The end of the spoke 7 is reinforced with a locking nut 71 on the aluminum alloy outer ring 2 of the duct. The structure is shown in Figure 10. The outer ring is mainly used to prevent the duct from deforming. The duct 1 is 3D printed with lightweight materials, which can reduce the weight of the fuselage while providing additional pulling force for the fuselage.

A flight control device is arranged at the middle bottom adjacent to the bottom shell 18, which is mainly composed of a steering gear 30, a rudder blade 5, a rotating shaft 3, a rudder blade fixing frame 13, a supporting shaft 31, and a flight control electronic device (the electronic device is not shown in the figure and is conventionally available on the market). Its structural components are shown in FIG8, wherein the supporting shaft 31 supports the rudder blade fixing frame 13 and connects the fixing frame 13 to the outer duct housing 1. The steering gear and the flight control electronic device are placed inside the middle component rudder blade fixing frame 13, the steering gear 30 is mounted at the lower end of the rudder blade fixing frame 13, the four rudder blades 5 are mounted on the rotating shaft 3 and the rudder blades can rotate around the rotating shaft, which can reduce the deflection torque of the steering gear 30; the deflection angle of the rudder blade 5 can be adjusted by the steering gear, which is specifically realized by connecting the rotating shaft of the steering gear 30 with the hole at the lower end of the rudder blade, and driving the lower end of the rudder blade to deflect at a certain angle through the rotation of the rotating shaft of the steering gear itself, thereby realizing the adjustment of the deflection angle of the rudder blade 5 around the rotating shaft. While the rudder blade 5 stably offsets the rotation torque, the steering gear 30 controls the deflection angle of the rudder blade 5 to achieve the navigation attitude control of the UAV.

The rudder blade 5 is not only used to offset the torque brought by the blade, but also to adjust the airflow direction at the lower end of the duct to achieve attitude adjustment of the UAV.

More specifically, the flight control system consists of two parts: one is the magnetic levitation support system that is started simultaneously when the UAV is started, and the other is a flight attitude control system based on a radial basis function neural network adaptive control algorithm developed in combination with the magnetic levitation support system. The algorithm uses the motor speed and the three attitude angles of the UAV itself as input, and the four rudder deflection angles as output. It relies on the rudder deflection angle values and the six directional forces of the UAV as mathematical models, uses radial basis function neural networks for training samples, and uses an adaptive sliding film algorithm to design a controller to improve the robustness of the flight control system, ensure adaptive adjustment of the control strategy when system parameters change, and achieve stable changes in the UAV's flight attitude.

Since the addition of the duct will be coupled with the aerodynamic characteristics of the duct, the aerodynamic characteristics of the ducted UAV structure are nonlinear, and the flight attitude control of the UAV is difficult. The reference diagram of the heading angle based on the flight attitude control system of the present invention is shown in Figure 11. The controllable variable of the ducted rotor is the UAV speed v, the rudder blade deflection angle α, and the four deflection angles are α ₁ , α ₂ , α ₃ , and α _4. The rolling angle of the UAV is obtained through the navigation attitude reference system AHRS. The pitch angle θ and yaw angle ψ are then used to control the heading attitude and adjust the deflection angle of the rudder blade through the RBF network-based adaptive control algorithm.

By adjusting the rudder blades, the rotor can achieve vertical take-off and landing, pitch, level flight and other attitude flight. The axially suspended ducted rotor structure has low rotation friction, high speed, large load and low noise, which can greatly improve flight stealth and load-bearing performance.

The flight control system is a combination of hybrid magnetic bearing control and conventional flight attitude control. Its flight attitude control module uses an adaptive sliding film control algorithm based on a radial basis function (RBF) neural network to reduce the flight attitude calculation time of the control system and accurately adjust the flight attitude deflection angle. The flow chart of the RBF network adaptive sliding film flight control algorithm is shown in Figure 12. It includes the following steps:

S1: Get the three attitude parameters of the drone reference (roll angle Pitch angle θ, yaw angle ψ), and its attitude angle is shown in Figure 11. The three attitude parameters after attitude solution are compared with the three attitude parameters of reference, and the difference is coded and solved and complementary filtered, and then input into the adaptive sliding membrane controller to output the attitude parameters;

S2: Adjust the steering gear deflection angle and motor speed according to the output attitude parameters;

S3: The adjusted steering gear deflection angle and motor speed are input into the RBF neural network for training;

S4: The steering gear deflection angle and motor speed parameters output after training re-enter the adaptive sliding membrane controller to obtain attitude parameters;

S5: repeat step S2. If the required control attitude is achieved, the adjusted steering gear deflection angle and motor speed are input into the UAV to perform a new attitude flight. If the required control attitude is not achieved, repeat steps S3 and S4.

S6: During the execution of the new attitude flight, the attitude reference system (AHRS) outputs the roll angle, pitch angle, and yaw angle of the drone;

S7: Perform attitude calculation based on real-time roll angle, pitch angle, and yaw angle, and calculate the attitude roll angle after attitude calculation. The pitch angle θ and yaw angle ψ parameters are compared with the three attitude parameters of the UAV reference, and adaptive control is performed cyclically.

Example 2

In the high-speed stealth UAV based on axial magnetic support implemented according to the present invention, a single fixed rotor disc motor with performance parameters shown in Table 1 is used, the blade parameters used are shown in Table 2, and the active magnetic suspension structure parameters are shown in Table 3.

Table 1 Performance parameters of single stator-rotor disc motor

name data name data Number of stator slots twenty four Maximum diameter of shaft 12mm Number of permanent magnets 28 Mechanical bearings GB6180 Stator outer diameter 96mm Stator-rotor air gap 1mm Stator inner diameter 21mm Turntable-axis height 59mm

Table 2 Blade structural parameters

parameter Numeric parameter Numeric airfoil NACA0012 Diameter/m 0.381 Blade chord length/m 0.036 Solidity 0.12 Number of blades/k 1×2 Air density/(kg/m ³ ) 1.243 Propeller disk load/N 176N

Table 3 Structural parameters of axial magnetic bearing

parameter Numeric parameter Numeric Stator outer diameter 54mm Rotor thickness 5mm Stator inner diameter 24.5mm Permanent magnet outer diameter 48mm Stator thickness 5.5mm Permanent magnet inner diameter 32mm Coil cavity area 1100mm ² Permanent magnet thickness 2.5mm Pole area 404mm ² Single-sided air gap 0.5mm Stator outer diameter 54mm Hybrid permanent magnet outer diameter 29mm Stator inner diameter 10mm Thickness of hybrid permanent magnet 1mm

Figure 13 is a motor speed-torque diagram designed according to Table 1, Figure 14 is a motor speed-power diagram designed according to Table 1, Figure 15 is a motor speed-current diagram designed according to Table 1, Figure 16 is an axial self-suspension magnetic field simulation diagram for the hybrid magnetic levitation bearing, and Figure 17 is a permanent magnet repulsive magnetic field simulation performed for the present invention.

Figure 13 shows the output torque corresponding to the increase in motor speed. When the motor speed reaches the rated speed of 9000rpm, the output torque reaches the maximum. Figure 14 shows the input power corresponding to the increase in motor speed. The maximum motor input power is 1.9kW. Figure 15 shows the input current corresponding to the increase in motor speed. The maximum input current is 55A. Figure 16 shows that the figure verifies the rationality of the magnetic circuit design. The arrows show the direction of the magnetic field inside the hybrid magnetic bearing. When a loop is formed, it means that an axial suspension force can be generated. Figure 17 verifies that the direction of the permanent magnet magnetic field is repulsive. The direction of the arrows is the direction of the same magnetic field. At this time, the state of the two magnetic rings is repulsive. The denser the magnetic field lines, the stronger the magnetic field strength.

The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims (9)

1. High rotational speed stealthy unmanned aerial vehicle based on axial magnetic force supports, its characterized in that includes:

the rotor wing device is formed by stacking two blade paddles on a driving device at an upper angle and a lower angle;

the driving device is a disc type permanent magnet motor, and a motor permanent magnet is arranged at the bottom of a motor turntable and is axially spaced from the electronic stator; the bottom of the disc type permanent magnet motor is provided with a passive permanent magnet;

The axial magnetic suspension structure is arranged below the disc type permanent magnet motor and comprises a magnetic suspension bearing turntable and a magnetic suspension bearing stator; the upper surface of the magnetic suspension bearing turntable is provided with another passive permanent magnet and forms a repulsive magnetic suspension structure with the passive permanent magnet at the bottom of the disc permanent magnet motor; the magnetic suspension bearing rotor sheet is arranged below the magnetic suspension bearing turntable, and the motor rotating shaft passes through the magnetic suspension bearing turntable and the magnetic suspension bearing stator inner ring;

The flight control device is arranged below the axial magnetic suspension structure and is used for controlling the navigation posture of the unmanned aerial vehicle;

A duct, a cylindrical enclosing rotor wing device is arranged from the periphery, and supporting devices are arranged at the bottom of the duct and the inner wall of the duct to realize radial and axial support.

2. The high-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 1, wherein the axial clearance between the magnetic bearing rotor sheet and the magnetic bearing stator is 0.5mm-1mm.

3. The high-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 1, wherein the rotor consists of two-bladed paddles which are vertically and angularly stacked on the turntable of the disk motor.

4. The high-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 1, wherein the axial magnetic suspension structure and the driving device are provided with an intermediate part housing for holding the vehicle, and the duct is fixedly connected with the intermediate part housing by the support structure.

5. The high-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 1, wherein the axial magnetic suspension structure and the driving device are provided with an intermediate part shell for forcing, and the duct and the intermediate part shell are in screw fastening connection by using a spoke type support structure with a rotation center as a rotation center.

6. The high-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 4, wherein the motor rotating shaft passes through the middle part shell and then is connected with the rolling contact device to form a buffer structure after passing out from the magnetic bearing turntable and the magnetic bearing stator inner ring, and an eddy current displacement sensor is arranged at the tail end of the motor rotating shaft to detect displacement.

7. The high-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 1 or 5, wherein the end part of the motor rotating shaft is fixedly installed by using a nut, an end face friction buffer structure is formed between the lower end face of the nut and a bottom plate by using a ball space, the bottom plate is fixed in an open circular groove at the bottom of the middle part shell and is provided with a central hole, and the eddy current displacement sensor is installed at the position of the central hole of the bottom plate.

8. The high-rotation-speed stealth unmanned aerial vehicle based on axial magnetic force support according to claim 1 or 5, wherein the magnetic bearing stator is a magnetic bearing stator with a U-shaped cross section, and the coil is arranged in the U-shaped groove.

9. The high-rotation-speed stealth unmanned aerial vehicle control method based on axial magnetic force support is characterized by comprising the following steps of:

S1, acquiring a roll angle of an initial reference of the unmanned aerial vehicle The pitch angle theta and the yaw angle phi are calculated, and three angle parameters after the gesture is calculated and the roll angle/>, which is considered, are calculatedComparing the pitch angle theta and the yaw angle phi, performing coding calculation and complementary filtering treatment on the difference value, and then inputting the difference value into the self-adaptive synovial membrane controller to output attitude parameters;

s2, adjusting a steering engine deflection angle and a motor rotating speed according to the output attitude parameters;

S3, inputting the adjusted steering engine deflection angle and motor rotation speed into an RBF neural network for training;

s4, re-entering the steering engine deflection angle and the motor rotating speed parameter which are output after training into the self-adaptive synovial membrane controller to obtain attitude parameters;

s5, repeating the step S2, inputting the adjusted steering engine deflection angle and the motor rotation speed into the unmanned aerial vehicle to execute the flight of the new gesture if the required control gesture is reached, and repeating the step S3 and the step S4 if the required control gesture is not reached;

s6: in the process of executing the new attitude flight, the attitude reference system outputs the roll angle, the pitch angle and the yaw angle of the unmanned aerial vehicle;

s7: and carrying out attitude calculation according to the real-time roll angle, pitch angle and yaw angle, comparing the angle parameters of the three roll angles, pitch angle and yaw angle after the attitude calculation with three attitude parameters of unmanned aerial vehicle attitude reference, and carrying out self-adaptive control circularly.