Multi-rotor linkage transmission mechanism of unmanned aerial vehicle and autonomous cooperative control method thereof

Abstract

The application belongs to the technical field of unmanned aerial vehicle control, and particularly relates to a multi-rotor linkage transmission mechanism of an unmanned aerial vehicle and an autonomous cooperative control method thereof, which comprises at least two groups of vertical stacked discrete power assemblies, the discrete power assembly comprises a motor, a rudder, a rotor, an inclined disc and a main shaft for providing central support, and the motor, the rudder, the rotor and the inclined disc are vertically stacked on the main shaft; wherein the main shaft is rotationally connected with a support disc through a bearing, the inclined disc comprises a rotation disc and a pushing disc which are vertically stacked, the rudder is fixedly installed on the support disc and is transmissionally connected with the pushing disc through a first linkage mechanism, and the rotation disc and the rotor are provided with a second linkage mechanism for changing the attack angle of the rotor. The application can realize more accurate control of the unmanned aerial vehicle, improve the control moment of the unmanned aerial vehicle, and greatly enhance the anti-interference ability and the ability to face complex environments of the unmanned aerial vehicle.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of unmanned aerial vehicle control, and particularly relates to a multi-rotor linkage transmission mechanism of an unmanned aerial vehicle and an autonomous cooperative control method thereof. BACKGROUND

[0002] Unmanned aerial vehicle rotor control technology is the core link of unmanned aerial vehicle flight stability, maneuverability and energy efficiency optimization, and is widely used in logistics transportation, agricultural plant protection, emergency rescue and other fields. With the development of multi-rotor unmanned aerial vehicles towards high speed, intelligence and clustering, the core of unmanned aerial vehicle rotor control technology lies in power assembly and dynamics modeling and simulation. The traditional rotor control method faces significant challenges in dynamic response accuracy, anti-interference ability and adaptability to complex environments.

[0003] At present, the unmanned power assembly is generally composed of a single power assembly, specifically including a motor, a rudder, a rotor, a tilt disc variable pitch mechanism and its mounting parts. The rotor is installed on the brushless motor rotor and is directly driven by the brushless motor to generate lift. The rotor mounting seat is provided with a rotating shaft and an installed bearing, so that the rotor can rotate around the rotating shaft, thereby changing the rotor attack angle and the lift size of the rotor at a specific phase to achieve the purpose of flight platform attitude control.

[0004] The traditional power assembly not only lacks in flight power, but also has low automaticity in flight control, resulting in low dynamic response accuracy, insufficient anti-interference ability of the unmanned aerial vehicle and insufficient ability to face complex environments, which cannot meet the current high degree of freedom control requirements of unmanned aerial vehicles. At the same time, the existing power model also cannot accurately control the rotor according to the real-time flight state of the unmanned aerial vehicle, and needs to be updated. SUMMARY

[0005] The purpose of the present application is to provide a multi-rotor linkage transmission mechanism of an unmanned aerial vehicle and an autonomous cooperative control method thereof, which can achieve more accurate control of the unmanned aerial vehicle, improve the control moment of the unmanned aerial vehicle, and greatly enhance the anti-interference ability of the unmanned aerial vehicle and the ability to face complex environments.

[0006] The technical solutions adopted by the present application are as follows:

[0007] The multi-rotor linkage transmission mechanism of the unmanned aerial vehicle comprises at least two groups of vertically stacked discrete power assemblies, the discrete power assembly comprises a motor, a rudder, a rotor, a tilt disc and a main shaft for providing central support, and the motor, the rudder, the rotor and the tilt disc are vertically stacked on the main shaft.

[0008] The main shaft is rotatably connected with a support disc through a bearing, the tilt disc comprises a rotating disc and a pushing disc stacked vertically, the steering engine is fixedly installed on the support disc and is drivingly connected with the pushing disc through a first linkage mechanism, and the rotating disc is provided with a second linkage mechanism for changing the attack angle of the rotor between the rotating disc and the rotor.

[0009] As a preferred solution, the relative driving ends of the rotors are provided with a rotating base, both ends of the rotating base are rotatably connected with hubs, and the rotors are fixedly installed on the hubs to synchronously drive the rotors to rotate.

[0010] As a preferred solution, the motors are oppositely installed on the upper and lower parts of the main shaft and generate opposite torsional moments, and the rotating base is fixedly installed on the power output end of the motor.

[0011] As a preferred solution, each group of the discrete power sources comprises at least three groups of the steering engines, and at least three groups of the first linkage mechanisms are provided between the steering engines and the pushing disc, and at least two groups of the second linkage mechanisms are provided between the rotating disc and the rotors to synchronously swing two groups of blades of the rotors.

[0012] As a preferred solution, a bearing is fixedly installed at the center of the rotating disc, a ball shaft is rotatably connected at the center of the bearing, and the ball shaft is fixedly sleeved on the main shaft, so that the rotating disc can perform three-dimensional swinging around the main shaft.

[0013] As a preferred solution, the first linkage mechanism comprises a transmission rod fixedly installed on the power output end of the steering engine, and a first linkage pull rod rotatably connected at the end of the transmission rod, and the first linkage pull rod is rotatably connected to the outer wall of the pushing disc.

[0014] As a preferred solution, the second linkage mechanism comprises an L-shaped swinging arm fixedly installed on a transverse support, and a second linkage pull rod rotatably connected to the outer wall of the rotating disc, so as to swing the rotors by pulling the rotating disc.

[0015] The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method is used for the unmanned aerial vehicle multi-rotor linkage transmission mechanism, and comprises the following steps:

[0016] S1, the satellite receiver is used to navigate and solve the satellite signal, the flight parameters of the unmanned aerial vehicle are measured in real time, and the measured flight parameter results are provided to the flight control unit to complete the control navigation task of the unmanned aerial vehicle;

[0017] S2, according to the specific operation data and the flight parameters in step S1, and based on the rotor flapping dynamics model and the rotor aerodynamic moment calculation model, the required taper angle, back rake angle and side rake angle of the rotor flight are generated;

[0018] S3, the taper angle, back rake and side rake required for the rotor flight calculated by the rotor flapping dynamics model in S2 are transmitted to the aerodynamic moment calculation model of the rotor as output parameters, to obtain the pitch control moment and roll control moment of the rotor;

[0019] S4, the motor and rudder are coordinately controlled by the flight control unit based on the pitch control moment and roll control moment, and then the flight state of the rotor is controlled through the first linkage mechanism and the second linkage mechanism, to realize the autonomous cooperative control of the flight state of the unmanned aerial vehicle.

[0020] As a preferred scheme, the rotor flapping dynamics model has the following specific dynamics equation:

[0021] The mathematical expression of the taper angle is: ;

[0022] Wherein, is the mass of the single rotor, is the rotor speed, is the distance from the hub center of the flapping hinge, is the air density, is the blade lift coefficient, is the blade area of the single rotor, is the blade stiffness coefficient, is the initial taper angle;

[0023] The mathematical expression of the back rake is: ;

[0024] Wherein, is the forward flight speed, is the rotor radius, is the pitch angle rate, is the forward flight speed coupling coefficient, is the pitch angle rate coupling coefficient;

[0025] The mathematical expression of the side rake is: ;

[0026] Wherein, is the sideslip speed, is the rotor speed, is the rotor radius, is the sideslip speed coupling coefficient, is the roll angle rate coupling coefficient, is the roll angle rate.

[0027] As a preferred scheme, the aerodynamic moment calculation model of the rotor has the following specific aerodynamic moment calculation equation:

[0028] The mathematical expression of the pitch control moment is: ;

[0029] wherein, is air density, is blade lift coefficient, is single rotor blade area, is rotor speed, is rotor radius, is longitudinal distance from rotor center to UAV center of gravity, is back chamfer, is single rotor mass, is distance from flap hinge center, is taper angle, is rotor moment of inertia, is roll angular rate;

[0030] The roll control moment mathematical expression is:

[0031] ;

[0032] wherein, is air density, is blade lift coefficient, is single rotor blade area, is rotor speed, is rotor radius, is left and right rotor distance, , is left and right rotor side chamfer, is single rotor mass, is forward flight speed, is side slip speed, is taper angle, is side chamfer damping coefficient, is side chamfer change rate.

[0033] The technical effects obtained by the present application are:

[0034] The present application drives the tilt plate to tilt through the steering gear, controls the change of the rotor pitch angle through the first linkage pull rod and the second linkage pull rod, and controls the change of the roll moment of the rotor through the motor, through the cooperation of the two, the change range of the rotor attack angle during the flight of the unmanned aerial vehicle is greatly improved, the power is sufficient, and the stability is stronger, so that the freedom of the rotor adjustment is higher, the unmanned aerial vehicle can be controlled more accurately, and the anti-interference ability and the ability to face complex environment of the unmanned aerial vehicle are greatly enhanced.

[0035] The application can achieve the purpose of precise control by establishing the rotor flapping dynamics model and the rotor aerodynamic moment calculation model, according to the actual flight state of the unmanned aerial vehicle and the satellite navigation task demand, through the control of the pitch moment and the roll moment of the rotor, while the setting of the multiple motors can meet the requirements of the anti-wind index, greatly improve the anti-interference ability and the ability to face complex environment of the unmanned aerial vehicle in the face of higher grade wind. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a perspective structural schematic diagram of the transmission mechanism embodiment of the application;

[0037] Figure 2 is a structural schematic diagram of the top part vertical power assembly in the transmission mechanism embodiment of the application;

[0038] Figure 3 is a structural schematic diagram of the bottom part vertical power assembly in the transmission mechanism embodiment of the application;

[0039] Figure 4 is a structural schematic diagram of the inclined disc in the transmission mechanism embodiment of the application;

[0040] Figure 5 is a side view structural schematic diagram of the transmission mechanism embodiment of the application;

[0041] Figure 6 is a top view sectional structural schematic diagram of the transmission mechanism embodiment of the application;

[0042] Figure 7 is a flow chart of the autonomous cooperative control in the control method embodiment of the application;

[0043] Figure 8 is a system architecture schematic diagram of the control method embodiment of the application;

[0044] Figure 9 is a structural schematic diagram of the flight control unit in the control method embodiment of the application.

[0045] In the drawings, the components represented by each reference numeral are listed as follows:

[0046] 1, main shaft;

[0047] 11, support disc;

[0048] 2, motor;

[0049] 3, steering engine;

[0050] 31, transmission rod; 32, first linkage pull rod;

[0051] 4, rotor; 41, rotating base; 42, hub; 43, L-shaped swing arm;

[0052] 5. tilt plate

[0053] 51. rotating plate; 52. pushing plate; 53. bearing; 54. ball shaft; 55. second linkage pull rod. DETAILED DESCRIPTION

[0054] In order to make the purpose and advantages of the present application more clear, the present application is specifically described below in combination with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present application, and does not strictly limit the protection scope of the present application.

[0055] As shown in Figures 1-6 , the unmanned aerial vehicle multi-rotor linkage transmission mechanism comprises two groups of vertically stacked discrete power assemblies, the discrete power assembly comprises a motor 2, a rudder 3, a rotor 4, a tilt plate 5 and a main shaft 1 for providing central support, the motor 2, the rudder 3, the rotor 4 and the tilt plate 5 are vertically stacked on the main shaft 1, and the two groups of discrete power assemblies are symmetrically arranged around the center of the main shaft 1, for respectively adjusting the flight attack angle of the rotor 4, so as to realize precise control of the unmanned aerial vehicle flight, and the main shaft 1 is a main force bearing component, and the through hole in the shaft can pass through the power and signal cables.

[0056] It should be noted that in some other embodiments, the discrete power assembly can be provided with at least two groups, three groups, four groups, etc. according to the flight requirements of the unmanned aerial vehicle.

[0057] Referring to the accompanying Figure 1 , Figure 5 and Figure 6 , in the present embodiment, the two groups of motors 2 are oppositely installed on the upper and lower parts of the main shaft 1, and respectively generate opposite roll control moments for respectively driving the two groups of rotors 4, so as to realize precise control thereof; wherein the motor 2 at the top is a first motor, the motor 2 at the bottom is a second motor, and the two groups of rotors 4 are respectively upper rotors and lower rotors, so that the upper rotors are driven by the first motor and the lower rotors are driven by the second motor.

[0058] Referring to the accompanying Figures 1-4 , the main shaft 1 is rotationally connected with a support plate 11 through a bearing 53, and the two groups of rudders 3 are fixedly installed on the support plate 11.

[0059] It should be noted that in the present embodiment, one group of rudders 3 is provided with three rudders, and two groups (i.e. six rudders 3) are symmetrically installed on the support plate 11. Of course, in some other embodiments, more than three rudders 3 can be provided according to the needs, so as to realize more dimensional control of the rotors 4.

[0060] The inclined disc 5 comprises a vertically stacked rotating disc 51 and pushing disc 52, and the rotating disc 51 is fixedly installed with a bearing 53 at the center, so that the whole inclined disc 5 can rotate around the whole main shaft 1 when the motor 2 is driven, the bearing 53 is rotationally connected with a ball shaft 54 at the center, and the ball shaft 54 is fixedly sleeved on the main shaft 1, so that the rotating disc 51 can perform three-dimensional swing around the main shaft 1.

[0061] Further, the power output end of the steering engine 3 is fixedly installed with a transmission rod 31, and the end of the transmission rod 31 is rotationally connected with a first linkage pull rod 32, and the first linkage pull rod 32 is rotationally connected to the outer wall of the pushing disc 52. The rotationally connected relationship among the transmission rod 31, the first linkage pull rod 32 and the pushing disc 52 is realized by a micro ball head shaft, so as to realize multi-angle power transmission. When the power output end of the steering engine 3 rotates, the power can be transmitted to the first linkage pull rod 32 through the transmission rod 31, and the pushing disc 52 and the rotating disc 51 are inclined and rotated around the ball shaft 54, so as to realize power transmission.

[0062] Again referring to the accompanying drawings Figures 1-4 The relative driving ends of the rotors 4 are provided with a rotating base 41, the rotating base 41 is rotationally connected with a hub 42 at both ends, and the rotors 4 are fixedly installed on the hub 42 to synchronously drive the rotors 4 to rotate, so that the rotors 4 can rotate circumferentially around the rotating base 41 to change the flight pitch angle. Meanwhile, the rotating base 41 is fixedly installed on the power output end of the motor 2, so that the motor 2 can drive the roll control torque to the rotors 4 through the rotating base 41, thereby controlling the flight of the rotors 4 and overcoming the counter-torque generated by the rotation of the rotors 4 (i.e., the first motor and the second motor drive the roll control torque to the upper rotor and the lower rotor through the rotating base 41 opposite to them, thereby controlling the flight of the rotors 4 and overcoming the counter-torque generated by the rotation of the upper rotor and the lower rotor 4).

[0063] It should be noted that in the embodiment, the motor 2 adopts a brushless motor 2 as the main power equipment, and a customized brushless outer rotor three-phase DC motor 2 is selected and is synchronously configured with a battery. The brushless motor 2 converts the electric energy of the battery into mechanical energy of the rotors 4, drives the rotors 4 to rotate at high speed to generate the required lift for flight, and the cable of the motor 2 is threaded through the hole of the main shaft 1. The rotors 4 are directly installed on the rotor of the power output end of the motor 2 through the rotating base 41, and are directly driven by the motor 2. Compared with gear speed change, the brushless motor 2 has fewer components, simpler structure and higher reliability, so that the unmanned aerial vehicle is more stable during flight and is easier to control.

[0064] Of course, in other embodiments, other types of motors 2 can be selected according to specific needs, such as a stepper motor 2, a brushed DC motor 2, a switched reluctance motor 2, etc.

[0065] Secondly, the L-shaped swing arm 43 is fixedly installed on the lateral support, and the second linkage pull rod 55 is rotatably connected to the outer wall of the rotating disc 51. The two are rotatably connected between the opposite ends, and the rotating connection is realized by a micro ball head shaft. In this way, the rotating disc 51 can pull the rotor 4 to swing, so that the control of the pitch angle of the rotor 4 is realized when the steering engine 3 rotates. When the steering engine 3 rotates, the power can be transmitted to the first linkage pull rod 32 through the transmission rod 31, and the push disc 52 and the rotating disc 51 are tilted and rotated around the ball shaft 54, and then the second linkage pull rod 55 transmits the pitch control moment to the rotor 4 through the L-shaped swing arm 43, so as to realize the control of the flight pitch angle of the rotor 4.

[0066] Therefore, by using the double-wing structure and the cooperation of the steering engine 3 and the inclined disc 5, the change range of the attack angle of the rotor 4 during flight of the unmanned aerial vehicle can be greatly improved, the power is sufficient, and the stability is higher. Therefore, the degree of freedom of the rotor 4 adjustment is higher, the unmanned aerial vehicle can be more accurately controlled, and the anti-interference ability and the ability to face complex environment of the unmanned aerial vehicle are greatly enhanced.

[0067] It should be noted that the rotating disc 51 and the main shaft 1 are further provided with a two-section retaining ring rotatably connected at the end. One end of the retaining ring is rotatably connected to the rotating disc 51 through a micro ball head shaft, and the other end is rotatably connected to a rotating sleeve. The rotating sleeve is rotatably connected to the main shaft 1 through a bearing 53, so as to maintain stability during power output and keep the rotating disc 51 rotating synchronously with the motor 2.

[0068] Further, the unmanned aerial vehicle in the embodiment is further provided with an electronic speed regulator for converting a control signal into a three-phase alternating current to realize motor 2 speed control. It is a main power device of the rotor 4 flight platform, and the specific parameters are as follows:

[0069] Table 1, electronic speed regulator parameter table

[0070] Parameter item Parameter value Remark Reference specification Customization 400A Outline size 113 x 105.5 x 40 mm irregular shape Irregular shape envelope Weight (g) Not less than 850 Heat dissipation mode Active heat dissipation Active heat dissipation device containing fan Maximum continuous power (W) 9800 Peak power (W) 5500 Duration not more than 30 s Operating voltage range 40~80V Maximum continuous current (A) 380A Duration not more than 30 s Control signal and communication protocol CAN / TTL State feedback Voltage, current, commutation speed, power device temperature

[0071] It has the advantages of reasonable heat dissipation design, high efficiency and compact structure. By strengthening the communication interface, it can reliably transmit voltage, current, commutation speed and temperature and other key working data through the serial port or CAN interface, so as to facilitate state transfer control and health check from the flight control end.

[0072] Of course, in other embodiments, other types of electronic speed regulators can be used, such as PWM signal speed regulator or digital communication speed regulator.

[0073] As shown in Figures 1-9 The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method is used to control the unmanned aerial vehicle multi-rotor linkage transmission mechanism in the embodiment, and includes the following steps:

[0074] Step one, the satellite receiver is used to solve the satellite signal, measure the flight parameters of the unmanned aerial vehicle in real time, and provide the measured flight parameter results to the flight control unit for completing the control and navigation task of the unmanned aerial vehicle.

[0075] The flight control unit communicates with the carrier platform through the detachable part on the machine body, and transmits the task binding data to the task computer in a transparent manner before take-off, and receives the ephemeris injection data and inertial navigation transfer alignment data of the carrier platform in a moving reference environment (such as take-off on a ship).

[0076] Step two, according to the specific operation data and the flight parameters in step one, and based on the rotor flapping dynamics model and the rotor aerodynamic moment calculation model, the required cone angle, back angle and side angle of the rotor flight are generated.

[0077] Step three, the required cone angle, back angle and side angle of the rotor 4 flight calculated by the rotor flapping dynamics model in step two are transmitted to the aerodynamic moment calculation model of the rotor 4 as output parameters, and the pitch control moment and roll control moment of the rotor 4 are obtained.

[0078] Step four, the motor 2 (synchronous control of the first motor and the second motor) and the steering gear 3 are controlled by the flight control unit based on the pitch control moment and the roll control moment, and the power output end of the steering gear 3 rotates and transmits power to the first linkage pull rod 32 through the transmission rod 31, and drives the push disc 52 and the rotating disc 51 to tilt and rotate around the ball shaft 54, and then the second linkage pull rod 55 transmits the pitch control moment to the rotor 4 (controlled by the first motor and the second motor and the steering gear 3 associated with them) through the L-shaped swing arm 43, and realizes the control of the flight pitch angle of the rotor 4 (the upper rotor and the lower rotor). At the same time, the motor 2 (the first motor and the second motor) controls the rotating speed of the rotor 4 (the upper rotor and the lower rotor) through the rotating base 41, so as to realize the autonomous cooperative control of the flight state of the unmanned aerial vehicle.

[0079] In this embodiment, the specific dynamics equation of the rotor flapping dynamics model is as follows:

[0080] The mathematical expression of the cone angle is: ;

[0081] Wherein, is the mass of the single rotor, the unit is kg; is the rotor speed, the unit is rad / s; is the distance from the hub center of the flapping hinge, the unit is m; is the air density, the unit is kg / m 3 , which is determined by the flight environment; is the lift coefficient of the blade, which needs to be obtained through wind tunnel test or CFD simulation, and the value in the embodiment is 0.95; is the area of the single rotor blade, and the unit is m 2 , which refers to the projected area of the blade; is the blade stiffness coefficient, and the value in the embodiment is 68, and the unit is N·m / rad; is the initial taper angle, and the unit is rad.

[0082] In the embodiment, the mathematical expression of the rear chamfer is: ;

[0083] wherein, is the forward flight speed, and the unit is m / s; is the rotor radius, and the unit is m; is the pitch rate, and the unit is rad / s; is the forward flight speed coupling coefficient, which is determined through experiment, and the value in the embodiment is 0.12; is the pitch rate coupling coefficient, which is determined through experiment, and the value in the embodiment is 0.3.

[0084] In the embodiment, the mathematical expression of the side chamfer is: ;

[0085] wherein, is the sideslip speed, and the unit is m / s; is the rotor speed, and the unit is rad / s; is the rotor radius, and the unit is m; is the sideslip speed coupling coefficient, which is determined through experiment, and the value in the embodiment is 0.15; is the roll rate coupling coefficient, which is determined through experiment, and the value in the embodiment is 0.075; is the roll rate, and the unit is rad / s.

[0086] In the embodiment, the specific aerodynamic moment calculation equation of the rotor 4 is as follows:

[0087] The mathematical expression of the pitch control moment is: ;

[0088] wherein, is the air density, and the unit is kg / m 3 , which is determined by the flight environment; is the lift coefficient of the blade, which needs to be obtained through wind tunnel test or CFD simulation, and the value in the embodiment is 0.95; is the area of the single rotor blade, and the unit is m 2 , which refers to the projected area of the blade; is the rotor speed, in rad / s; is the rotor radius, in m; is the longitudinal distance from the rotor center to the center of gravity of the UAV, in m; is the back chamfer, in rad; is the mass of a single rotor, in kg; is the distance from the hub center to the flap hinge, in m; is the taper angle, in rad; is the roll angular velocity; in rad / s.

[0089] wherein, is the rotor moment of inertia, in kg·m 2 , and the calculation formula is: .

[0090] In this embodiment, the mathematical expression of the roll control moment is:

[0091] ;

[0092] wherein, is the air density, in kg / m 3 , determined by the flight environment; is the blade lift coefficient, which needs to be obtained through wind tunnel test or CFD simulation, and the value in this embodiment is 0.95; is the area of a single rotor blade, in m 2 , referring to the projected area of the blade; is the rotor speed, in rad / s; is the rotor radius, in m; is the distance between the left and right rotors, in m; , is the side chamfer of the left and right rotors, in rad; is the mass of a single rotor, in kg; is the forward flight speed, in m / s; is the side slip speed, in m / s; is the taper angle, in rad; is the side chamfer damping coefficient, and the value in this embodiment is 85, in N·m·s / rad; is the side chamfer change rate, in rad / s.

[0093] It should be noted that the flight control unit in step one contains flight controllers and communication links and other devices. In this embodiment, the flight controller master chip adopts a hardware scheme based on Cortex-M7 kernel, with a main frequency of 216MHz, and has good performance in both computing power and power consumption. The inertial navigation system adopts a dual-redundancy design, supports transfer alignment on a moving platform (such as a ship, aerospace platform) through a reference device or an external high-precision inertial navigation system, completes the initialization of the sub-inertial navigation system on the flight control, and the accuracy of the aligned heading angle is better than 0.2°, the pitch / roll angle is better than 0.5°, and the alignment time is less than 120 seconds. The main indicators are shown in the following table:

[0094] Table II. Main performance parameters of IMU

[0095] IMU Degrees of freedom GYRO range GYRO noise ACC range ACC noise Operating temperature SMC200 6 ±2000° 0.0061° ±40g 12.75µ / g -40-105℃ BMI088 6 ±2000° 0.014° ±24g 175µ / g -40-85℃

[0096] Further, the satellite receiver in step one is the main navigation and positioning component of the control unmanned aerial vehicle. By performing navigation calculation on satellite signals, the flight state information of the unmanned aerial vehicle is measured in real time, and the measurement results are provided to the flight control unit for completing the integrated navigation task. The main parameters are as follows:

[0097] Table III. Main parameters of satellite receiver

[0098] Parameter item Parameter value Single point positioning accuracy Plane: 1.5 m; elevation: 2.5 m RTK positioning accuracy Plane: 0.8 cm + 1 ppm; elevation: 1.5 cm + 1 ppm Speed measurement accuracy Not more than 0.2 m / s Capture time Cold start less than 20 s; initialization time less than 5 s (typical value) Signal frequency BDS B1I / B2I / B3I / B1C / B2a / B2b Channel 1408 channels, based on Nebulas IV Update frequency 50 Hz Voltage Direct current 3.6 V-6.0 V, typical 5.0 V Current 80 mA / 5.0 V

[0099] Referring to the accompanying Figure 9 , the flight control unit carries a flight control software for unmanned aerial vehicle flight control. The flight control software is developed by mixed programming of C / C++ language. The architecture is based on layered design, which can improve the stability and scalability of the flight control system. Specifically, the flight control software architecture includes the following levels:

[0100] Task interface layer:

[0101] This layer serves as the interface between the flight control software and users or external devices, responsible for receiving and processing instructions and data from users or external devices. The task interface layer is connected to the external world through a communication interface, and can support multiple communication protocols and data formats.

[0102] Control logic layer:

[0103] The control logic layer includes an outer loop navigation control module and an inner loop attitude control module. The outer loop navigation control module generates flight instructions based on the received navigation information (such as position and speed data provided by the GNSS module). The inner loop attitude control module adjusts the attitude based on the flight instructions and real-time acquired unmanned aerial vehicle attitude information (such as data from the inertial measurement unit), to ensure that the unmanned aerial vehicle flies according to the predetermined trajectory.

[0104] Hardware abstraction layer:

[0105] The hardware abstraction layer is located between the control logic layer and the underlying hardware, serving as an interface between the two. This layer is responsible for converting the operation requests of the control logic layer to the hardware into instructions that the hardware can understand, and processing the state information returned by the hardware. The hardware abstraction layer can support multiple hardware devices and sensors, such as inertial measurement units, electronic compasses, barometric / speed meters, etc.

[0106] The embedded operating system layer:

[0107] The embedded operating system layer serves as the foundation platform of the flight control software, providing functions such as task scheduling, resource management, and interrupt handling. This layer provides a stable running environment for the upper-layer software (such as the control logic layer and the hardware abstraction layer), and supports the concurrent execution of multiple tasks. The embedded operating system layer can ensure the real-time performance and reliability of the flight control software.

[0108] The external interface layer:

[0109] The external interface layer is located at the bottom of the flight control software architecture, responsible for connecting and communicating with other external devices. This layer includes barometric / speed meter interfaces and other external interfaces, and can support the access and data transmission of multiple external devices. The external interface layer enables the flight control software to flexibly integrate and cooperate with other systems or devices.

[0110] In the architecture design, clear interfaces are used for interaction and communication between layers, achieving decoupling and modularization of different functional modules. This layered design not only improves the scalability and maintainability of the flight control system, but also enables the system to flexibly adapt to different types of unmanned aerial vehicle hardware and sensors.

[0111] During actual flight, the control moment of the unmanned aerial vehicle under different flight states can be calculated by testing the rotor control moment model. The total moment angle of the rotor is kept at 15° under the high-efficiency state, and in the hovering state, the size of the roll moment and angular acceleration is tested under the rated roll control input A1 = 13° and the rated pitch control input B1 = 13°, respectively. Because in the hovering windless state, the positive and negative control inputs have symmetry, only the response state under positive control input needs to be measured.

[0112] At the maximum forward flight speed of 25 m / s, the wind disturbance lifting moment of rotor 4 (upper rotor and lower rotor) is the largest, and due to the windward waving effect of rotor 4 (upper rotor and lower rotor), the pitch and roll moments of upper and lower rotors 4 are no longer the same, so it is necessary to test the response state of the positive and negative rated control inputs of the pitch and roll channels separately. In order to ensure sufficient control moment, the roll control input and pitch control input need to be increased, i.e. |A1| is not less than 13° and |B1| is not less than 13°, in order to improve the control ability.

[0113] According to the previous rotor pull calculation results, the rotating speed of the rotor 4 (upper rotor and lower rotor) is set to stably operate under different working conditions. The attitude response of the unmanned aerial vehicle is measured by angular acceleration, and its value is equal to the moment divided by the moment of inertia of the unmanned aerial vehicle around the x and y axes. The moment of inertia of the unmanned aerial vehicle around the center of mass in pitch and roll is Ix = 5.8 kg· , Iy = 5.8 kg· . The results obtained through simulation test are as follows:

[0114] Table Four, pitch control response data

[0115] Inflow velocity Inflow angle Rotor speed Roll control input (degrees) Moment (N.m) Angular acceleration (rad / s2) Whether the criterion is met 0 0 2016 13 52.44 9.04 Yes 25 -10 1958 13 70.02 12.07 Yes 25 -10 1958 -13 -29.17 -5.03 Yes 25 10 1723 13 64.70 11.15 Yes 25 10 1723 -13 -20.52 -3.54 Yes 25 -20 2373 13 78.38 13.51 Yes 25 -20 2373 -13 -37.72 -6.50 Yes 25 20 1664 13 66.22 11.42 Yes 25 20 166 -13 -18.62 -3.21 Yes 25 -30 2317 13 91.11 15.71 Yes 25 -30 2317 -13 -50.35 -8.68 Yes 25 30 1579 13 68.59 11.83 Yes 25 30 1579 -13 -18.24 -3.14 Yes 20.7 0 2016 0 19.2 3.31 Yes 20.7 0 2016 -7 -9.1 -1.57 -

[0116] According to the simulation results described above, it can be known that:

[0117] (1) In the case of no wind in the hovering state, the absolute value of the attitude control response angular acceleration is greater than 9 rad / s , the response is very fast, which is greater than the design index 3.14 rad / s , and meets the actual index requirements.

[0118] (2) At the maximum forward flight speed of 25 m / s, the wind disturbance lifting moment of the rotor is different at different angles of attack of the incoming flow, so the pitch control moment is also different under the same pitch control input B1. When the angle of attack of the incoming flow increases from -30° to 30°, the wind disturbance lifting moment increases continuously, resulting in a smaller pitching moment under the same control output. Especially when the angle of attack is 30°, B1 needs to be less than -13° to meet the control quality requirements.

[0119] (3) When the unmanned aerial vehicle hovers, if there is a horizontal 8-level gust (wind speed equivalent to 20.7 m / s), the instantaneous lifting moment of the unmanned aerial vehicle is 19.2 N·m. At this time, if the minimum pitch cyclic pitch control of -7° is applied, a pitching moment of -9.1 N·m will be generated, which can basically balance the lifting moment caused by the disturbance, and the control amount is less than the maximum allowed pitch angle of the power assembly 13°, indicating that the control moment of the unmanned aerial vehicle is sufficient and meets the 8-level wind resistance index requirements.

[0120] The above is only a preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application. The structures, devices and operation methods not specifically described and explained in the present application, such as without special description and limitation, are implemented according to the conventional means in the art.

Claims

1. An unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method, characterized in that, The method comprises the following steps: S1, the satellite receiver is used to solve the satellite signal, the flight parameters of the unmanned aerial vehicle are measured in real time, and the measured flight parameter results are provided to the flight control unit to complete the control and navigation task of the unmanned aerial vehicle; S2, according to the specific operation data and the flight parameters in S1, and based on the rotor flapping dynamics model and the rotor aerodynamic moment calculation model, the required cone angle, back rake angle and side rake angle for rotor flight are generated; S3, the required cone angle, back rake angle and side rake angle for rotor flight calculated by the rotor flapping dynamics model in S2 are transmitted to the rotor aerodynamic moment calculation model as output parameters to obtain the pitch control moment and roll control moment of the rotor; S4, the motor and the rudder are controlled by the flight control unit based on the pitch control moment and the roll control moment, and then the first linkage mechanism and the second linkage mechanism are used to control the rotor flight state to realize the autonomous cooperative control of the unmanned aerial vehicle flight state; The specific dynamics equation of the rotor flapping dynamics model is as follows: The taper angle is mathematically expressed as: ; wherein, is the mass of the single rotor, is the rotor speed, is the distance from the center of the flapping hinge to the hub, is the air density, is the blade lift coefficient, is the single rotor blade area, is the blade stiffness coefficient, is the initial taper angle; The mathematical expression for the back chamfer is: ; wherein, is the forward flight velocity, is the rotor radius, is the pitch rate, is the forward flight velocity coupling coefficient, is the pitch rate coupling coefficient; The mathematical expression of the side chamfer is: ; wherein, is the sideslip velocity, is the rotor speed, is the rotor radius, is the sideslip velocity coupling coefficient, is the roll rate coupling coefficient, is the roll rate.

2. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 1, characterized in that, The specific aerodynamic moment calculation equation of the rotor aerodynamic moment calculation model is as follows: The mathematical expression of the pitch control moment is: ; wherein, is the air density, is the blade lift coefficient, is the single sided rotor blade area, is the rotor speed, is the rotor radius, is the longitudinal distance from the rotor center to the UAV center of gravity, is the back chamfer, is the single sided rotor mass, is the distance from the flap hinge to the hub center, is the taper angle, is the rotor moment of inertia, is the roll angular rate; The mathematical expression of the roll control moment is: ； wherein, is the air density, is the blade lift coefficient, is the single rotor blade area, is the rotor speed, is the rotor radius, is the left-right rotor spacing, , is the left-right rotor side rake, is the single rotor mass, is the forward flight speed, is the side slip speed, is the taper angle, is the side rake damping coefficient, is the side rake rate of change.

3. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 1, characterized in that, It also includes at least two groups of vertically stacked discrete power assemblies, the discrete power assembly includes a motor, a rudder, a rotor, an inclined disc and a main shaft for providing central support, the motor, the rudder, the rotor and the inclined disc are vertically stacked on the main shaft; Wherein, the main shaft is rotatably connected with a support disc through a bearing, the inclined disc includes a rotating disc and a pushing disc which are vertically stacked, the rudder is fixedly installed on the support disc and is connected with the pushing disc through the first linkage mechanism, the rotating disc and the rotor are provided with the second linkage mechanism for changing the attack angle of the rotor.

4. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 3, characterized in that, The rotating base is provided between the relative driving ends of the rotor, the both ends of the rotating base are rotatably connected with hubs, and the rotor is fixedly installed on the hubs to synchronously drive the rotor to rotate.

5. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 4, characterized in that, The motor is oppositely installed on the upper and lower parts of the main shaft, and generates opposite torsional moments.

6. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 3, characterized in that, Each group of the discrete power assembly includes at least three groups of the rudder, and at least three groups of the first linkage mechanism are provided between the rudder and the pushing disc, and at least two groups of the second linkage mechanism are provided between the rotating disc and the rotor to synchronously swing two groups of blades of the rotor.

7. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 3, characterized in that, The bearing is fixedly installed at the center of the rotating disc, the ball shaft is rotatably connected at the center of the bearing, and the ball shaft is fixedly sleeved on the main shaft, so that the rotating disc can swing in three dimensions around the main shaft.

8. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 3, characterized in that, The first linkage mechanism includes a transmission rod fixedly installed on the power output end of the rudder, and a first linkage pull rod rotatably connected at the end of the transmission rod, the first linkage pull rod is rotatably connected to the outer wall of the pushing disc.

9. The unmanned aerial vehicle multi-rotor linkage transmission mechanism autonomous cooperative control method according to claim 4, characterized in that, The second linkage mechanism includes an L-shaped swing arm fixedly installed on a transverse support and a second linkage pull rod rotatably connected to the outer wall of the rotating disc, and the two are rotatably connected to pull the rotor to swing through the rotating disc.

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