A variable configuration tiltable tri-copter unmanned aerial vehicle and control method thereof

Abstract

A variable configuration tiltable three-rotor unmanned aerial vehicle and a control method thereof, comprising an unmanned aerial vehicle body, a power module and a three-way alloy connecting piece, the unmanned aerial vehicle body is composed of two layers of composite material plates, and a storage space is arranged between the two layers of composite material plates; the power module adopts a two-degree-of-freedom tilting structure design; the unmanned aerial vehicle body and the power module are connected through the three-way alloy connecting piece. The control method comprises designing a position controller and an attitude controller; obtaining the position information and the attitude information of the unmanned aerial vehicle and inputting into the control, obtaining the expected thrust and the expected moment; taking the expected thrust and the expected moment as known quantities, solving the expected tilting angle and the expected thrust of each power module based on a control efficiency model and a power module dynamics model. The present application realizes full decoupling of position and attitude, has the ability to fly in any direction at any attitude and fast attitude maneuvering capability. The present application can be widely applied in the field of unmanned aerial vehicle technology.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a variable-configuration tiltable tri-rotor UAV and its control method. Background Technology

[0002] With the continuous development of UAV technology and the diversification of application scenarios, the demand for rotorcraft is also constantly evolving. Some application scenarios require higher flight efficiency and payload capacity. For example, some long-endurance missions require greater endurance, while some missions carrying heavy loads require higher payload capacity. This leads to the exploration of new rotorcraft configuration schemes. The tri-rotor is a configuration scheme that is gradually gaining attention in the UAV field. It uses three independently rotating rotors, distributed at three corners of the aircraft. Compared to quadcopters, tri-rotors have some unique advantages. First, tri-rotors offer improved efficiency. With only three rotors, one less than a quadcopter, it reduces aerodynamic drag and improves flight efficiency. Second, the tri-rotor design can provide higher payload capacity because each rotor bears a larger load. Furthermore, tri-rotors have better maneuverability than quadcopters. With appropriate control strategies, tri-rotors can achieve more flexible and agile flight maneuvers, such as rapid acceleration, sharp turns, and high-speed flight. In addition, tri-rotors help reduce the overall weight and complexity of the aircraft. Compared to a quadcopter, a tri-rotor eliminates one rotor and its associated transmission system, thereby reducing the aircraft's structural weight and maintenance costs. Furthermore, the reduction in rotor size simplifies the aerodynamic layout of a tri-rotor, allowing for a larger angle between the two rotors and the fuselage. This facilitates the installation of various sensors, such as vision and radar sensors, enabling its application in more intelligent scenarios.

[0003] While existing tri-rotor drones possess the aforementioned advantages, they also suffer from disadvantages such as poor stability, poor maneuverability, poor anti-interference ability, and poor fault tolerance, and there is a problem that the anti-torque cannot be canceled out. Summary of the Invention

[0004] To address the aforementioned technical problems, the objective of this invention is to provide a variable-configuration tiltable tri-rotor unmanned aerial vehicle and its control method. The three rotors are designed as a two-degree-of-freedom tilt vector propulsion mode, achieving full decoupling of position and attitude, and enabling flight in any attitude and direction with rapid attitude maneuvering capabilities.

[0005] The technical solution adopted in this invention is: a variable-configuration tiltable tri-rotor unmanned aerial vehicle (UAV), comprising a UAV fuselage, a power module, and a three-way alloy connector, wherein:

[0006] The drone's fuselage is composed of two layers of composite material panels, with a storage space between the two layers.

[0007] The power module adopts a two-degree-of-freedom tilt structure design and is equipped with an axial tilt servo and a lateral tilt servo.

[0008] The upper and lower composite material plates of the drone fuselage are equipped with planar bearings. The first and second ends of the three-way alloy connector are connected to the upper and lower composite material plates respectively through the planar bearings. The third end of the three-way alloy connector is connected to the power module through a deep groove ball bearing, so that the power module and the drone fuselage can rotate freely.

[0009] Furthermore, the power module includes a frame assembly, a longitudinal tilt servo, a lateral tilt servo, a support tube, and a motor module, wherein:

[0010] The lateral tilt servo is connected to the frame assembly and is used to drive the frame assembly to rotate;

[0011] One end of the support rod is connected to the longitudinal tilting servo motor via a deep groove ball bearing, and the other end is connected to the frame assembly via a deep groove ball bearing.

[0012] The motor module is installed at the midpoint of the support tube;

[0013] The axial tilt servo motor drives the motor module to rotate via a support rod.

[0014] Furthermore, the power module is also equipped with an orientation sensor to measure the orientation between each power module.

[0015] Furthermore, the control method for a variable-configuration tiltable tri-rotor unmanned aerial vehicle includes the following steps:

[0016] Design position and attitude controllers based on feedback linearity and cascaded PID controllers;

[0017] Obtain the current position and attitude information of the drone;

[0018] The current position information, current attitude information, desired attitude information, and desired position information are input into the position controller and attitude controller for calculation to obtain the desired thrust and desired torque.

[0019] A control efficiency model is constructed, and the desired thrust and desired torque are used as model inputs to obtain the desired pull force of each power module;

[0020] A dynamic model of the boom power unit is constructed, and the rotation matrix of each power module around the boom and motor mounting axis is obtained by taking the expected tension of each power module as input.

[0021] The desired tilt angle is calculated based on the rotation matrix of each power module around the arm and motor mounting axis;

[0022] The desired thrust of each power module is input into the motor, and the desired tilt angle is input into the longitudinal tilt servo and the lateral tilt servo, respectively.

[0023] Furthermore, the position controller has the following expression:

[0024] F B =mR T (u p -g)

[0025]

[0026] e v =v d -v

[0027]

[0028] Among them, F B Let m represent the desired thrust, P represent the weight of the UAV, R represent the current position information, and R represent the current attitude information. T The matrix representing the inverse of the current attitude information, u p This represents virtual input, which is achieved by adjusting u. p To control this, g = (0, 0, -g) T Represents gravitational acceleration in the world coordinate system. and This represents the positive definite diagonal matrix of PID parameters, e v This represents the difference between the current speed and the desired speed. Let v represent the difference vector between the current velocity and the desired velocity. d Let P represent the desired speed, v represent the current speed, and P represent the desired speed. d This indicates the desired location information.

[0029] Furthermore, the attitude controller has the following expression:

[0030]

[0031] e ω =ω d -ω

[0032]

[0033] Among them, M B ω represents the desired torque, and ω represents the angular velocity. Represents the gain matrix. and Represents the gain matrix of the angular velocity controller, e ω This represents the difference between the current angular velocity and the desired angular velocity. ω represents the vector difference between the current angular velocity and the desired angular velocity.d R represents the desired angular velocity. d Represents the desired attitude information, ∨ represents the inverse operation of exponentiation, J∈R 3×3 This represents the positive definite inertia matrix.

[0034] Furthermore, the control efficiency model is expressed as follows:

[0035]

[0036] in, and R1, R2, and R3 represent the expected tensile force at the equivalent point of action of each power module, and R1, R2, and R3 represent the position vectors at the equivalent point of action of each power module.

[0037] Furthermore, the expression for the desired tensile force at the equivalent point of action of each power module in the dynamic model of the boom power unit is as follows:

[0038]

[0039] Among them, f i B R represents the desired tensile force at the equivalent point of application of each power module. z Indicates revolving around z B The basic rotation matrix of the axis, R αi R represents the rotation matrix around the arm. ρi Let represent the rotation matrix about the motor mounting axis, α represent the tilt angle about the arm, ρ represent the tilt angle about the motor mounting axis, and t represent the rotation matrix about the motor mounting axis. i This indicates the thrust generated by each rotor.

[0040] The beneficial effects of the method and system of this invention are as follows: By installing two sets of tilting mechanisms on the three rotors, this invention enables the tri-rotor UAV to possess two degrees of freedom vector thrust. The combination of vector thrust can effectively solve the problem of the inability to cancel out anti-torque, while greatly improving the stability and maneuverability of the tri-rotor UAV. The design of the tilting power unit also improves its fault tolerance. In the event of a failure of one rotor, the UAV can still maintain stability and land safely by relying on the vector combination of the remaining tilting rotors. At the same time, it can adapt well to the changes in the center of gravity caused by different loads, always keeping the center of gravity at the geometric center of the rotor, ensuring controllability. The variability of the configuration and the hierarchical control strategy based on thrust vectors allow the UAV to adjust its flight attitude arbitrarily, thereby passing through some narrow areas that were previously inaccessible. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0042] Figure 2This is a power module diagram of a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0043] Figure 3 This is a schematic diagram of a three-way alloy connector for a variable-configuration tiltable tri-rotor UAV according to the present invention;

[0044] Figure 4 This is a schematic diagram of the passive variable configuration of a tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0045] Figure 5 This is a flight status illustration of a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0046] Figure 6 This is a flowchart of a control method for a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0047] Figure 7 This is a control system framework diagram of a control method for a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0048] Figure 8 This is a schematic diagram of the coordinate system and power unit numbering of the control method for a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0049] Figure 9 This is a rendering of the control method for a variable-configuration tiltable tri-rotor unmanned aerial vehicle according to the present invention;

[0050] Figure descriptions: 1. Longitudinal tilt servo; 2. Lateral tilt servo; 3. LiDAR; 4. Right obstacle avoidance camera; 5. Flight control; 6. Upper fisheye camera; 7. Left obstacle avoidance camera; 8. GPS; 9. Bottom fisheye camera; 10. Onboard computer (NUC); 11. Parallel computing onboard computer; 12. Front obstacle avoidance camera; 13. Deep groove ball bearing; 14. Frame assembly; 15. Motor mount; 16. Motor module; 17. Support tube. Detailed Implementation

[0051] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0052] Reference Figure 1 This invention provides a variable-configuration tiltable tri-rotor unmanned aerial vehicle (UAV), comprising a UAV fuselage, a power module, and a three-way alloy connector, wherein:

[0053] The drone's fuselage is composed of two layers of triangular composite material plates, with a storage space between the two layers of composite material plates.

[0054] Preferably, the storage space of the present invention stores airborne equipment such as a lidar 3, a right obstacle avoidance camera 4, a GPS 8, a flight controller 5, an upper fisheye camera 6, a left obstacle avoidance camera 7, a bottom fisheye camera 9, an airborne computer NUC 10, a parallel computing onboard computer 11, and a front obstacle avoidance camera 12; the lower plate of the UAV fuselage can suspend a load to cope with changes in the center of gravity of the UAV. The lidar 3, right obstacle avoidance camera 4, left obstacle avoidance camera 7, and front obstacle avoidance camera 12 can be used to acquire the position of obstacles, thereby adjusting the desired position and attitude of the UAV to achieve obstacle avoidance during the journey to the destination; the GPS 8 is used to acquire the current position information of the UAV; the onboard computer NUC 10 and the parallel computing onboard computer 11 are used to store the control algorithm and receive the position and attitude information measured by the sensing sensors and orientation sensors, and calculate the desired thrust and desired tilt angle based on the control algorithm; the flight controller 5 is used to input the desired thrust to the motor and the desired tilt angle to the longitudinal tilt servo 1 and the lateral tilt servo 2 respectively; the upper fisheye camera 6 and the lower fisheye camera 9 are used to better capture the surrounding environment, facilitating attitude switching when controlling the UAV flight;

[0055] The power module adopts a two-degree-of-freedom tilt structure design and is equipped with an axial tilt servo and a lateral tilt servo 2.

[0056] In a specific embodiment of the present invention, there are three identical power modules (also referred to as drone arms), which are respectively installed on the three corners of the drone's triangular fuselage via three-way alloy connectors.

[0057] Preferably, such as Figure 2 As shown, the power module includes a frame assembly 14, a longitudinal tilt servo motor 1, a lateral tilt servo motor 2, a support tube 17, and a motor module 16, wherein:

[0058] The frame component 14 is a semi-circular frame made of composite material. The semi-circular frame structure can save a lot of space when it is quickly disassembled and stored, making it more suitable for carrying.

[0059] The lateral tilt servo 2 is installed together with the frame assembly 14, driving the frame assembly 14 to rotate, and the lateral tilt servo 2 itself moves accordingly;

[0060] The motor module 16 is installed at the midpoint of the support tube 17; wherein, the motor module 16 further includes a motor base 15; the motor base 15 has a columnar gap in the middle for the support rod to pass through; the motor base 15 is installed at the midpoint of the support tube 17; the motor module 16 is installed on the motor base 15;

[0061] The longitudinal tilt servo 1 has a different driving mode than the transverse tilt servo 2. When the longitudinal tilt servo 1 drives the support tube 17 to rotate, the servo itself will not rotate. Therefore, one end of the support rod is connected to the longitudinal tilt servo 1 through a deep groove ball bearing 13, and the other end is connected to the frame assembly 14 through a deep groove ball bearing 13. The rotation of the deep groove ball bearing 13 drives the motor module 16 to rotate.

[0062] The drone fuselage and power module are connected by a three-way alloy connector.

[0063] Preferably, such as Figure 3 As shown, each of the upper and lower composite material plates of the UAV fuselage is equipped with a planar bearing. The first and second ends of the three-way alloy connector are connected to the upper and lower composite material plates through the planar bearings, and the third end of the three-way alloy connector is connected to the power module through the deep groove ball bearing 13, so that the power module and the UAV fuselage can rotate freely and realize the variable configuration active control of the center of gravity.

[0064] Preferably, to address the changes in the center of gravity caused by different payloads on the drone, thereby expanding the drone's application range, different types of equipment are mounted on different positions on the drone. The power module is also equipped with an orientation sensor to measure the orientation between the power modules and adjust the tilt angle of the power modules, achieving a variable configuration for the tri-rotor. For example... Figure 4 As shown, when the center of gravity shifts and approaches one side of the tri-rotor configuration triangle, the load on two of the rotors increases, the control lever arm shortens, resulting in a decrease in the reachable torque set of the UAV and weakened stability. This can be achieved by controlling the UAV to... Figure 4 The triangular configuration change on the right can always keep the center of gravity at the rotor geometry center, thus maintaining controllability.

[0065] Reference Figure 5 This solution, based on the variable configuration of a three-rotor aircraft and combined with a power module designed with a two-degree-of-freedom tilt structure, can achieve hovering in any attitude, such as... Figure 5 As shown in (a), the UAV of this specific embodiment can keep its fuselage horizontal when flying forward; as Figure 5 As shown in (b), the UAV of this invention can maintain a large fuselage pitch angle when flying forward; as Figure 5 As shown in (c), the UAV body of this specific embodiment achieves rapid directional maneuvering through vector thrust; as Figure 5 As shown in (d), the UAV of this invention can achieve vertical flight; as Figure 5 As shown in (e), the UAV of this invention can achieve horizontal flight in a high-maneuverability mode; as Figure 5 As shown in (f), the UAV of this invention can stand upright in a high-mobility mode.

[0066] Reference Figure 6 A control method for a variable-configuration tiltable tri-rotor unmanned aerial vehicle (UAV) includes the following steps:

[0067] S1. Design position controllers and attitude controllers based on feedback linearity method and cascade PID controller;

[0068] Specifically, since the desired tension of the UAV fuselage and the two-degree-of-freedom vector tension generated by the power module can be derived independently, the UAV as a whole adopts a hierarchical control strategy based on the tension vector. Based on the dynamic model of the UAV, the position controller and attitude controller are designed by combining the feedback linear method and the cascade PID controller.

[0069] The dynamics model of an unmanned aerial vehicle (UAV) includes a position dynamics model, an attitude dynamics model, a control efficiency model, and an arm power unit dynamics model. The dynamics model and attitude dynamics model are the basis for designing the position controller and attitude controller. The control efficiency model plays a key role in controlling and distributing thrust and torque. The arm power unit dynamics model further converts the desired thrust into the control tilt angle of the servo motor.

[0070] The position dynamics model is expressed as follows:

[0071]

[0072] Among them, F B This represents the desired thrust, and m represents the weight of the UAV. R represents position information, and R represents attitude information. g = (0, 0, -g) T This represents the gravitational acceleration in the world coordinate system.

[0073] The attitude dynamics model is expressed as follows:

[0074]

[0075] Among them, M B Let J represent the desired torque, ω represent the angular velocity, ∧ represent the exponentiation operation, and J∈R. 3×3 R represents the positive definite inertia matrix, and R represents the attitude information. This represents the attitude vector.

[0076] The control efficiency model is expressed as follows:

[0077]

[0078] in, and R1, R2, and R3 represent the desired tensile force at the equivalent point of application of each power module, and R1, R2, and R3 represent the position vectors at the equivalent point of application of each power module. The position vectors at the equivalent point of application of each power module can be expressed as:

[0079]

[0080] Where L represents the distance between the rotor center and the center of the UAV on the horizontal plane, and h represents the height of the rotor center relative to the center of the UAV in the vertical direction.

[0081] The dynamic model of the arm power unit is expressed as follows:

[0082]

[0083] Among them, f i B R represents the desired tensile force at the equivalent point of application of each power module. z Indicates revolving around z B The basic rotation matrix of the axis, R αi R represents the rotation matrix around the arm. ρi Let represent the rotation matrix about the motor mounting axis, α represent the tilt angle about the arm, ρ represent the tilt angle about the motor mounting axis, and t represent the rotation matrix about the motor mounting axis. i This indicates the thrust generated by each rotor.

[0084] Based on the position dynamics model, the position controller uses a cascaded PID controller to control the UAV's position, and employs a feedback linearization method to achieve better control performance by defining a new virtual input u. p This is used to control the position P of the drone. The position controller has the following expression:

[0085] F B =mR T (u p -g)

[0086]

[0087] e v =v d -v

[0088]

[0089] Among them, F B Let m represent the desired thrust, P represent the weight of the UAV, R represent the current position information, and R represent the current attitude information. T The matrix representing the inverse of the current attitude information, u p This represents virtual input, which is achieved by adjusting u. p To control this, g = (0, 0, -g)T Represents gravitational acceleration in the world coordinate system. and This represents the positive definite diagonal matrix of PID parameters, e v This represents the difference between the current speed and the desired speed. Let v represent the difference vector between the current velocity and the desired velocity. d Let P represent the desired speed, v represent the current speed, and P represent the desired speed. d This indicates the desired location information.

[0090] Based on the attitude dynamics model, since position and attitude are completely decoupled, we can arbitrarily give the desired attitude. Therefore, the attitude controller is designed in the form of so(3), and feedback linearization and PID control are used to design the angular velocity loop. The expression of the attitude controller is as follows:

[0091]

[0092] e ω =ω d -ω

[0093]

[0094] Among them, M B ω represents the desired torque, and ω represents the angular velocity. Represents the gain matrix. and Represents the gain matrix of the angular velocity controller, e ω This represents the difference between the current angular velocity and the desired angular velocity. ω represents the vector difference between the current angular velocity and the desired angular velocity. d R represents the desired angular velocity. d Represents the desired attitude information, ∨ represents the inverse operation of exponentiation, J∈R 3×3 This represents the positive definite inertia matrix.

[0095] S2. Obtain the current position and attitude information of the drone;

[0096] Specifically, refer to Figure 8 The world coordinate system of this invention adopts the Northeast Eastern Geodetic (NED) coordinate system: {O W ,x W ,t W ,z W}. Body coordinate system {O B ,x B ,y B ,z B The origin is located at the centroid, x B The axis points along the arm towards rotor #2, y B Axis perpendicular to xB The axis points to the left, z B The axis is perpendicular to {O} B ,x B ,y B The plane points upwards. The location of the machine system's origin in the world system is represented as P = [x, y, z]. T The attitude of the machine system relative to the world system is represented by so(3) as R, and the angular velocity in the machine system is ω=[ω x ω y ω z ] T By using the orientation sensor on the power module and the perception sensors mounted on the drone body, the current position and attitude information of the drone can be accurately obtained. The position information also includes the drone's flight speed, and the attitude information includes the angular velocity of the drone's power module.

[0097] S3. Input the current position information, current attitude information, desired attitude information and desired position information into the position controller and attitude controller for calculation to obtain the desired thrust and desired torque;

[0098] Specifically, refer to Figure 7 After inputting the current position information, current attitude information, desired attitude information, and desired position information into the position controller and attitude controller, the desired thrust and desired torque required to move the UAV to the desired position in the desired attitude can be calculated according to the expressions of the position controller and attitude controller in step S1.

[0099] S4. Construct a control efficiency model and use the desired thrust and desired torque as model inputs to obtain the desired pull force of each power module;

[0100] Specifically, refer to Figure 7 Substituting the desired thrust and desired torque into the control efficiency model in step S1, we can obtain the following from the control efficiency model:

[0101]

[0102] Substituting the dimension-reduced matrix E into the above expression, we get:

[0103]

[0104] in, This represents the control efficiency matrix after dimensionality reduction. Next, the pseudo-inverse method can be used to solve for f. i B :

[0105]

[0106] Then, the desired tension at the equivalent point of action of each power module is substituted into the dynamic model of the boom power unit. Based on the expression of the desired tension at the equivalent point of action of each power module, the rotation matrix around the boom and the rotation matrix around the motor mounting axis are calculated and solved.

[0107] S5. Calculate the desired tilt angle based on the rotation matrix of each power module around the arm and motor mounting axis;

[0108] Specifically, refer to Figure 7 On the right half, based on the specific expressions of the rotation matrices around the boom and around the motor mounting axis in the boom power unit dynamic model, the tilt angle around the boom can be directly calculated. and the tilt angle around the motor mounting shaft

[0109] This invention provides another solution for determining the desired tilt angle, which involves obtaining the desired tension f at the equivalent point of action of each power module. i B Then, the desired tensile force is decomposed into forces along x. B The tensile force vector along the axis, along y B The tensile force vector along the axis, along z B The tension vector of the shaft is then used to transform the expression in the dynamic model of the boom power unit. The desired tilt angle is replaced with the unknown term to be determined, and the desired tension at the equivalent point of action of each power module is taken as the known term. After the replacement, the expression for the desired tilt angle is as follows:

[0110]

[0111] in, This represents the desired tilt angle of power module i around the arm. f represents the desired tilt angle of power module i about the motor mounting axis. ix f iy and f iz Represented as along x B The tensile force vector along the axis, along y B The tensile force vector along the axis, along z B The tensile force vector of the shaft.

[0112] S6. Input the desired pull force of each power module into the motor, and input the desired tilt angle into the longitudinal tilt servo and the lateral tilt servo respectively;

[0113] Specifically, the desired pulling force of each of the three power modules is input into the motor, and the desired tilt angle of power module i around the arm is determined. The input is given to the longitudinal tilt servo, which controls the desired tilt angle of the power module i around the motor mounting axis. Input into the lateral tilt servo.

[0114] Reference Figure 9 Using the control method of this invention for drone flight control, since the power system can tilt with two degrees of freedom, the fuselage attitude can remain unchanged during flight, with only the power system tilting. When the drone moves forward or backward, the rotor rotates around the y-axis. B Axial tilt forward / backward, with controller compensation to ensure -z B The directional lift remains constant. When making lateral movements, the rotor rotates around the x-axis. B The rotors tilt to the left and right sides, providing lateral acceleration and enabling the drone to move to the left and right. When the drone is navigating, the three rotors tilt around the arms at the same angle, efficiently generating a very strong navigating control torque without adding acceleration in other directions.

[0115] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A control method of a variable-configuration tiltable three-rotor unmanned aerial vehicle, characterized in that: it is applied to a variable-configuration tiltable three-rotor unmanned aerial vehicle comprising an unmanned aerial vehicle body, a power module and a three-way alloy connecting piece, wherein: the unmanned aerial vehicle body is composed of two layers of composite material plates, and a storage space is arranged between the two layers of composite material plates; the power module is designed in a two-degree-of-freedom tilting structure, and is provided with a longitudinal tilting servo and a transverse tilting servo; the two layers of composite material plates of the unmanned aerial vehicle body are provided with plane bearings, the first end and the second end of the three-way alloy connecting piece are connected to the upper and lower layers of composite material plates through the plane bearings, and the third end of the three-way alloy connecting piece is connected to the power module through a deep groove ball bearing, so that the power module and the unmanned aerial vehicle body can rotate freely; the power module comprises a frame assembly, a longitudinal tilting servo, a transverse tilting servo, a support pipe and a motor module, wherein: the transverse tilting servo is connected to the frame assembly to drive the frame assembly to rotate; one end of the support pipe is connected to the longitudinal tilting servo through a deep groove ball bearing, and the other end is connected to the frame assembly through a deep groove ball bearing; the motor module is installed at the midpoint of the support pipe; the longitudinal tilting servo drives the motor module to rotate through the support pipe; the power module is also provided with an azimuth sensor for measuring the azimuth between the power modules; comprising the following steps: designing a position controller and an attitude controller based on a feedback linearization method and a cascade PID controller; obtaining current position information and attitude information of the unmanned aerial vehicle; inputting the current position information, the current attitude information, the expected attitude information and the expected position information into the position controller and the attitude controller for calculation to obtain expected thrust and expected moment; constructing a control efficiency model, and taking the expected thrust and the expected moment as model inputs to obtain expected tension of each power module; constructing a power dynamics model of the power module, and taking the expected tension of each power module as input to obtain a rotation matrix of each power module around the arm and the motor installation shaft; calculating the expected tilting angle based on the rotation matrix of each power module around the arm and the motor installation shaft; inputting the expected tension of each power module into the motor, and inputting the expected tilting angle into the longitudinal tilting servo and the transverse tilting servo respectively; the control efficiency model has the following expression: wherein, and denote the desired pull force at the equivalent action point of each power module, R1, R2, and R3 denote the position vector at the equivalent action point of each power module, F B denotes the desired thrust, M B denotes the desired moment; the expected tension of each power module equivalent action point in the power dynamics model of the power module has the following expression: where f i B denotes the desired tension at the equivalent action point of each power module, R z denotes the elementary rotation matrix around the z B axis, R αi denotes the rotation matrix around the motor arm, R ρi denotes the rotation matrix around the motor mounting axis, a denotes the tilt angle around the motor arm, p denotes the tilt angle around the motor mounting axis, t i denotes the tension generated by each rotor.

2. The control method of the variable configuration tiltable tri-copter unmanned aerial vehicle according to claim 1, wherein, the position controller has the following expression: F B = mR T (u p -g) e v = v d - v where F B denotes the desired thrust, m denotes the weight of the UAV, P denotes the current position information, R denotes the current attitude information, R T denotes the inverse matrix of the current attitude information, u p denotes the virtual input, which is controlled by adjusting u p , g = (0, 0, -g) T denotes the gravity acceleration in the world coordinate system, and denotes a positive definite diagonal matrix of PID parameters, e v denotes the difference between the current speed and the desired speed, e v denotes the difference vector between the current speed and the desired speed, v d denotes the desired speed, v denotes the current speed, P d denotes the desired position information.

3. The control method of the variable configuration tiltable tri-copter unmanned aerial vehicle according to claim 1, wherein, the attitude controller has the following expression: e ω = ω d - ω where M B denotes a desired torque, ω denotes an angular velocity, denotes a gain matrix, and denotes an angular velocity controller gain matrix, e ω denotes a difference between a current angular velocity and a desired angular velocity, denotes a difference vector between a current angular velocity and a desired angular velocity, ω d denotes a desired angular velocity, R d denotes desired attitude information, ∨ denotes an inverse operation of multiplication, J ∈ R 3×3 denotes a positive definite inertia matrix.

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