A control method for a rotor unmanned aerial vehicle based on lift feedback

Abstract

The present application relates to the field of unmanned aerial vehicle control, in particular to a rotor unmanned aerial vehicle control method based on lift feedback, the rotor unmanned aerial vehicle control method based on lift feedback includes designing unmanned aerial vehicle control framework with lift feedback power system and lift closed loop controller based on rotor lift model and motor electric governor model. First, remove the motor speed inverse solution module in the traditional power system in the unmanned aerial vehicle control framework, increase the lift feedback control module, use the sensor to measure the lift generated by the rotor, realize closed loop control;Second, the power system model of multi-rotor unmanned aerial vehicle is established, the motor throttle is taken as the input, and the rotor lift is taken as the output;Finally, based on this model, the input-output linearization force closed loop controller is designed to accurately control the lift output. The method solves the problems of low control accuracy and poor flight stability of the rotor unmanned aerial vehicle in the wind disturbance environment operation or maneuvering flight process. By applying this control method to the rotor unmanned aerial vehicle to ensure its high precision control and stable flight in the wind disturbance environment and maneuvering flight process.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) control, and more specifically to a control method for a rotorcraft UAV based on lift feedback. Background Technology

[0002] Multi-rotor unmanned aerial vehicles (UAVs) have been widely used in search and rescue, high-altitude scientific research, and other fields due to their high maneuverability and ease of operation. With the continuous advancement of UAV control technology, research focus has gradually shifted to improving mission complexity, control accuracy, and robustness. For example, precise control of output lift is crucial for UAVs in navigation missions or performing rapid obstacle avoidance maneuvers in windy environments. Traditional lift models for multi-rotor UAVs typically employ static aerodynamic models that link motor speed to rotor lift, assuming that the lift generated by the rotor is proportional to the square of the motor speed with a constant proportionality coefficient. However, in actual UAV flight, this type of quadratic model does not consider the impact of wind disturbance on the rotor downwash, and therefore has only proven effective in static lift test platforms, UAV hovering, low-speed flight, and windless environments. Because this model ignores the influence of relative airflow velocity on lift, the lift value calculated by the static lift model will have significant deviations when the UAV is flying at high speed or in the presence of wind disturbance.

[0003] To address this issue, existing methods are mainly divided into three categories: First, rotor lift estimation based on aerodynamic models, which establishes a lift model through the momentum theorem and blade element momentum theory, but requires precise solution of induced velocity and aerodynamic parameters, resulting in poor adaptability; second, lift model training based on learning methods, which uses machine learning techniques such as reinforcement learning to directly train the lift model, but has high computational cost and poor generalization ability; and third, feedback control based on direct signal measurement, which uses strain gauges or accelerometers to measure lift or acceleration to achieve closed-loop control, but is susceptible to noise interference and difficult to accurately control single-axis lift. Summary of the Invention

[0004] The problem addressed by this invention is the low control accuracy of rotary-wing UAVs operating in windy environments or during maneuvering flight. It proposes a lift feedback-based control method for rotary-wing UAVs, solving the problems of low control accuracy and poor flight stability during windy operations or maneuvering flight.

[0005] The solution of this invention is: a control method for a rotary-wing unmanned aerial vehicle based on lift feedback, comprising the following steps:

[0006] Step 1: Construct a rigid body dynamics model of the quadcopter UAV to map the total lift and torque of the UAV to the hybrid control distributor of the desired lift of each axis power system;

[0007] Step 2: Establish a lift feedback control module for the UAV that includes lift measurement and closed-loop control, so as to perform closed-loop control of the single-axis power system via an electronic speed controller;

[0008] Step 3: Establish a rotor lift aerodynamic model considering wind disturbance based on the momentum theorem and the blade element momentum theorem, and solve for the induced velocity to obtain the rotor lift T;

[0009] Step 4: Based on the single-axis power system model of the UAV, a lift feedback controller is constructed by adopting the input-output feedback linearization method;

[0010] Step 5: Based on the rigid body dynamics model of the quadcopter UAV, determine the desired lift T required by each rotor axis. d,i The lift feedback control module of the UAV enables the lift feedback controller to output a control law to the electronic speed controller in order to dynamically adjust the rotor lift.

[0011] Step 1 is as follows:

[0012] Step 1.1: Construct the position dynamics and attitude dynamics model of the rotary-wing UAV:

[0013]

[0014] In the formula, p = [x, y, z] T Indicates position, v = [v x ,v y ,v z ] T Let represent velocity, g represent gravitational acceleration, m represent the mass of the drone, and e3 = [0, 0, 1]. T The unit vector representing the z-axis. Let Θ = [φ, θ, ψ] represent the rotation matrix from the body coordinate system to the inertial coordinate system. T The attitude angles of the UAV are represented by φ, θ, and ψ, where φ, θ, and ψ represent the roll angle, pitch angle, and yaw angle, respectively; ω = [ω x ,ω y ,ω z ] T Indicates the angular velocity of the machine body. This represents the moment of inertia of a rotary-wing drone. Represents the rate of change of attitude angle The relationship matrix between f and the body's rotational angular velocity ω, f and M = [M x M y M z ] T These represent the total lift and torque of the UAV, respectively.

[0015] Step 1.2: Establish a model showing the relationship between the total lift f and torque M of the quadcopter UAV and the lift T of each rotor axis, i.e., the hybrid control allocation matrix is:

[0016]

[0017] In the formula, d is the distance from the geometric center of the machine body to the central axis of any motor, and c τ is a constant, representing an approximate relationship between lift and torque.

[0018] Step 2 is as follows:

[0019] Step 2.1: Based on the desired position p d and desired yaw angle ψ d The desired total lift f is obtained through an inner-outer loop cascade PID controller. d and desired torque M d And through the mixing distributor, the desired total lift f d and desired torque M d The desired lift T mapped to each rotor axis d,i i = 1, 2, 3, 4, representing the axis numbers of the UAV; the outer ring includes the position controller and the velocity controller, and the inner ring includes the attitude controller and the angular velocity controller;

[0020] Step 2.2: Establish the lift feedback module;

[0021] The lift T generated by the rotor is directly measured using sensors. m,i A Kalman filter is used to reduce the influence of measurement noise in order to obtain the filtered lift value T. k,i Next, with T d,i and T k,i Using the control quantity u as the input and the control quantity u as the output, a lift feedback controller is constructed so that the electronic speed governor adjusts the equivalent voltage U according to the control quantity u. i Control the motor to generate speed This drives the propellers on each shaft to generate corresponding lift T. i .

[0022] Step 3 includes the following steps:

[0023] Step 3.1: Construct the MT lift model and calculate the lift generated by the rotor based on the momentum balance of the rotor:

[0024]

[0025] In the formula, ρ represents air density, R represents rotor disk radius, and v i Indicates the induction velocity; and V represents the actual air velocity on the rotor.a Horizontal and vertical components; V s =V w -V is the airflow velocity passing through the rotor, V w V is the wind speed, and V is the drone's flight speed; and there is in and V s Horizontal and vertical components, For v i The vertical component;

[0026] Combined with aerodynamic model Using the MT lift model, the lift coefficient is obtained:

[0027]

[0028] Step 3.2: Perform independent aerodynamic analysis on each blade element unit according to the BEMT (Beam-Momentum Theorem) to obtain the overall rotor lift coefficient:

[0029]

[0030] Where N b c represents the number of rotor blades. tip C is the chord length at the tip of the blade. lα Let θ be the slope of the lift curve. tip The blade tip pitch angle, This refers to the motor speed;

[0031]

[0032] C2=θ tip

[0033] The BEMT lift model is obtained as follows:

[0034]

[0035] Step 3.3: Equivalent to the lift coefficient in Step 3.1 and Step 3.2, solve the induced velocity using the combined equations to obtain the expression:

[0036]

[0037] Where C3=2ρπR 2 ;

[0038] Step 3.4: Solve for the induced velocity v i The numerical solution, in v i >0 is used as a constraint condition, that is v corresponding to the minimum value i The desired induced velocity is:

[0039]

[0040] stv i >0

[0041] The obtained induced velocity v i The lift T of a single rotor can be calculated by substituting it into the BEMT lift model.

[0042] Step 4 is as follows:

[0043] For the single-axis propulsion system model of the UAV, the input is the electronic speed controller control quantity u, the output is the lift y = T, and the state variable is the motor angular velocity x = ω. The goal is to make the output y of the UAV's single-axis propulsion system track the desired value y. d Expected value y d As a lifting T i Introducing error e = y d -y, whose derivative is Design the virtual control law as follows: in k0 is a constant; the output of the lift feedback controller is:

[0044]

[0045]

[0046] c2=2C1C2β 2 ,

[0047] C e C is the back electromotive force constant. m For electromagnetic torque constant and C e Equivalent, R m R is the equivalent resistance of the motor. e For the equivalent internal resistance of the electronically controlled switch, f m J is the coefficient of viscous friction between the motor and the load referred to the motor shaft. m Let α be the moment of inertia of the motor and load referred to the motor shaft, and M be the load torque. c The torque coefficient, β, has an approximately linear relationship with the lift force T, and represents the motor speed. The speed coefficient, U, has a linear relationship with the motor's angular velocity ω. e The input voltage of the brushless motor is obtained by the electronic speed controller linearly adjusting the control quantity u; R represents the rotor disk radius. The horizontal component representing the actual air velocity on the rotor. Represents the vertical component, v i Indicates the induced velocity. For V sThe vertical component, V s =V w -V is the airflow velocity passing through the rotor; V w V represents wind speed, and V represents the drone's flight speed. For V s The horizontal component.

[0048] A control method for a rotary-wing unmanned aerial vehicle based on lift feedback includes:

[0049] The rigid body dynamics model building module is used to build a rigid body dynamics model of a quadcopter UAV, so as to map the total lift and torque of the UAV to the hybrid control distributor of the desired lift of each axis power system;

[0050] The UAV lift feedback control module is used to establish a UAV lift feedback control module that includes lift measurement and closed-loop control, so as to perform closed-loop control of the single-axis power system via an electronic speed controller;

[0051] The rotor lift aerodynamic model building module is used to establish a rotor lift aerodynamic model considering wind disturbance based on the momentum theorem and the blade element momentum theorem, and solve for the induced velocity to obtain the rotor lift T.

[0052] The lift feedback controller construction module is used to construct a lift feedback controller based on a single-axis UAV power system model by adopting an input-output feedback linearization method.

[0053] The rotary-wing UAV control module is used to implement the rigid body dynamics model of a quadcopter UAV based on the desired lift T required by each rotor axis. d,i The lift feedback control module of the UAV enables the lift feedback controller to output a control law to the electronic speed controller in order to dynamically adjust the rotor lift.

[0054] The present invention has the following advantages and beneficial effects:

[0055] 1. The lift feedback control strategy proposed in this invention removes the motor speed inverse solution module in the traditional underlying flight control structure and designs and adds a rotor lift feedback control module to accurately control the lift generated by the rotor, thereby improving the control accuracy and flight stability of the UAV in windy environments or during maneuvering flight.

[0056] 2. The UAV single-axis propulsion system modeling module in this invention establishes a rotor lift aerodynamic model considering wind disturbance by combining the momentum theorem (MT) and the blade element momentum theorem (BEMT). It also accurately solves for the induced velocity by simultaneously solving the MT and BEMT lift models, improving the effectiveness of the induced velocity solution and the accuracy of the lift model estimation. Furthermore, by establishing a differential equation model of the brushless DC motor and combining it with the lift aerodynamic model, accurate modeling of the rotor UAV single-axis propulsion system is achieved.

[0057] 3. The lift feedback controller designed in this invention dynamically adjusts the lift generated by the rotor through input-output linearized closed-loop control to control the required lift output of the power system. Attached Figure Description

[0058] Figure 1 This is a diagram of the underlying flight control framework of the rotary-wing unmanned aerial vehicle of the present invention. Detailed Implementation

[0059] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and specific examples.

[0060] This invention relates to the field of unmanned aerial vehicle (UAV) control, specifically to a lift feedback-based control method for rotorcraft UAVs. The method includes designing a UAV control framework with a lift feedback power system and a lift closed-loop controller based on a rotor lift model and a motor ESC model. First, the motor speed inverse kinematics module in the traditional power system is removed from the UAV control framework, and a lift feedback control module is added. Sensors are used to measure the lift generated by the rotor to achieve closed-loop control. Second, a power system model of the multi-rotor UAV is established, with motor throttle as input and rotor lift as output. Finally, an input-output linearized force closed-loop controller is designed based on this model to precisely control the lift output. This method solves the problems of low control accuracy and poor flight stability of rotorcraft UAVs operating in windy environments or during maneuvering flight. By applying this control method to rotorcraft UAVs, high-precision control in windy environments and during maneuvering flight can be ensured.

[0061] This invention proposes a control method for a rotorcraft unmanned aerial vehicle (UAV) based on lift feedback. The main contents of this method include: 1) designing a lift feedback control strategy, removing the motor speed inverse kinematics module in the traditional flight control structure, and adding a lift feedback control structure to accurately control the lift output of the rotor; 2) establishing a single-axis power system model of the rotorcraft UAV, including the establishment of a motor ESC model and a rotor lift model considering wind disturbance; 3) designing a lift feedback controller, using an input-output feedback linearization method to design a closed-loop controller for rotor lift.

[0062] A lift feedback-based control method for rotary-wing unmanned aerial vehicles (UAVs) achieves lift feedback control by designing a UAV control framework with a lift feedback power system and a lift closed-loop controller based on a rotor lift model and a motor ESC model. The method includes the following steps:

[0063] Establishment of the quadrotor UAV dynamics model: A rigid body dynamics model of the quadrotor UAV was established, and a hybrid control distributor was designed to accurately map the total lift and torque of the UAV to the desired lift of each axis of its power system. Design of the UAV control framework with lift feedback: Based on the traditional rotor UAV power system framework, the speed inverse solution module that converts the rotor's desired lift into motor speed control was removed, and a UAV lift feedback control module including lift measurement and closed-loop control was designed. Establishment of the single-axis power system model of the rotor UAV: ​​First, a rotor lift aerodynamic model considering wind disturbance was established based on the momentum theorem (MT) and blade element momentum theorem (BEMT), and the induced velocity was solved by simultaneously solving the MT and BEMT lift models. Second, a brushless DC motor-electrically controlled differential equation model was established. Finally, the single-axis power system model of the UAV was obtained by combining the lift aerodynamic model and the brushless DC motor model. Design of the lift feedback controller: An input-output feedback linearization method was used to design a lift feedback controller to dynamically adjust the lift generated by the rotor.

[0064] The dynamic modeling of the quadcopter UAV includes the following steps:

[0065] Step 1: Construct the position dynamics and attitude dynamics model of the rotary-wing UAV:

[0066]

[0067] In the formula, p = [x, y, z] T Indicates position, v = [v x ,v y ,v z ] T Let represent velocity, g represent gravitational acceleration, m represent the mass of the drone, and e3 = [0, 0, 1]. T The unit vector representing the z-axis. Let Θ = [φ, θ, ψ] represent the rotation matrix from the body coordinate system to the inertial coordinate system. T The attitude angles of the UAV are represented by φ, θ, and ψ, where φ, θ, and ψ represent the roll angle, pitch angle, and yaw angle, respectively; ω = [ω x ,ω y ,ω z ] T Indicates the angular velocity of the machine body. This represents the moment of inertia of a rotary-wing drone. Represents the rate of change of attitude angle The relationship matrix between f and the body's rotational angular velocity ω, f and M = [M x M y M z ] T These represent the total lift and torque of the UAV, respectively.

[0068] Step 2: Establish a model showing the relationship between the total lift f and torque M of the quadcopter UAV and the lift T of each rotor axis, i.e., the hybrid control allocation matrix is:

[0069]

[0070] In the formula, d is the distance from the geometric center of the machine body to the central axis of any motor, and c τ is a constant, representing an approximate relationship between lift and torque.

[0071] The modeling of the UAV single-axis propulsion system includes the following steps:

[0072] Step 1: Calculate the lift generated by the rotor based on the momentum balance of the rotor according to the momentum theorem (MT):

[0073]

[0074] In the formula, ρ represents air density, R represents rotor disk radius, and v i Indicates the induction velocity; and V represents the actual air velocity on the rotor. a Horizontal and vertical components; V s =V w -V is the airflow velocity passing through the rotor, V w V is the wind speed, and V is the drone's flight speed; and there is in and V s Horizontal and vertical components, For v i The vertical component;

[0075] Combining classic aerodynamic models ( Based on the motor speed and the MT lift model, the lift coefficient is obtained:

[0076]

[0077] Step 2: Perform independent aerodynamic analysis on each blade element according to the Blade Element Momentum Theorem (BEMT) to obtain the overall rotor lift coefficient:

[0078]

[0079] Where N b c represents the number of rotor blades. tip C is the chord length at the tip of the blade. lα Let θ be the slope of the lift curve. tip Let be the blade tip pitch angle, and let

[0080]

[0081] C2=θ tip

[0082] The BEMT lift model can be obtained as follows:

[0083]

[0084] Step 3: The lift coefficients of MT and BEMT are equivalent. By combining the two equations to solve for the induced velocity, the simplified expression is obtained:

[0085]

[0086] Where C3=2ρπR 2 ;

[0087] Step 4: Construct an optimization model to solve for the induced velocity v i The numerical solution, in v i >0 is used as a constraint condition, that is v corresponding to the minimum value i The desired induced velocity is:

[0088]

[0089] stv i >0

[0090] The obtained induced velocity v i The rotor lift T can be calculated by substituting it into the BEMT lift model;

[0091] Step 5: Establish the differential equation model of the brushless DC motor and its electronic speed controller, with the motor angular velocity ω as the output and the control quantity u as the input:

[0092]

[0093] Among them, C e C is the back electromotive force constant. m For electromagnetic torque constant and C e Equivalent, R m R is the equivalent resistance of the motor. e For the equivalent internal resistance of the electronically controlled switch, f m J is the coefficient of viscous friction between the motor and the load referred to the motor shaft. m Let α be the moment of inertia of the motor and load referred to the motor shaft, and M be the load torque. c The torque coefficient, β, has an approximately linear relationship with the lift force T, and represents the motor speed. The speed coefficient, U, represents the linear relationship between the speed (RPM) and the motor's angular velocity ω (rad / s). eThe input voltage of the brushless motor is obtained by the electronic speed controller linearly adjusting the control quantity u according to the control quantity u.

[0094] Step 6: Combining the MT lift model, BEMT lift model, and motor-electro-tuner differential equation model described above, establish a single-axis power system model for the UAV. The input is the control variable u, the output is the lift y = T, and the state variable is the motor angular velocity x = ω.

[0095]

[0096] In the formula,

[0097]

[0098] c2=2C1C2β 2 ,

[0099] The design of the input-output linearization controller includes the following steps:

[0100] Step 1: Design the control law based on the UAV dynamic system model to obtain the linear relationship between the input u and the output y:

[0101] u=(v-(-2c2a1x 3 -(2c2a2+c1a1)x 2 -(2c2a0+c1a2)x-c1a0)) / (2c2b0x+c1b0)

[0102] In the formula, v is the virtual control law, and the input-output mapping is obtained as follows:

[0103] Step 2: To make the system output y track the desired value y d Define the error e = y d -y, the error derivative is

[0104]

[0105] Design the virtual control law as follows: The final control law for the power system is:

[0106]

[0107] This invention proposes a control method for rotary-wing unmanned aerial vehicles (UAVs) based on lift feedback. This method includes the design of a UAV control framework with a lift feedback power system and the design of a lift closed-loop controller based on a rotor lift model and a motor ESC model. It solves the problems of low control accuracy and poor flight stability of rotary-wing UAVs operating in windy environments or during maneuvering flight. The specific steps are as follows:

[0108] (1) Establishment of dynamic model of quadcopter UAV

[0109] A rigid body dynamics model of a quadcopter UAV is established to obtain a hybrid control distributor that can accurately map the total lift and torque of the UAV to the desired lift of its respective axis power system.

[0110] (2) Design of UAV control framework with lift feedback

[0111] Based on the traditional rotorcraft UAV power system framework, the rotational speed inverse solution module that converts the desired rotor lift into motor speed control quantity is removed, and a UAV lift feedback control module that includes lift measurement and closed-loop control is designed.

[0112] (3) Modeling of the single-axis power system of a rotary-wing UAV

[0113] Based on the momentum theorem (MT) and the blade element momentum theorem (BEMT), a rotor lift aerodynamic model considering wind disturbance is established, and the induced velocity is solved by combining the MT and BEMT lift models. A brushless DC motor-electrically controlled differential equation model is established. Combining the lift aerodynamic model and the brushless DC motor model, a single-axis power system model of the UAV is obtained.

[0114] (4) Lift Feedback Controller Design

[0115] Based on the established UAV power system model, an input-output linearized closed-loop controller is designed to dynamically adjust the lift generated by the rotor and control the power system to output the required lift.

[0116] Specific examples are as follows:

[0117] A lift feedback simulation platform for a quadrotor UAV was built in the Matlab environment. The controller includes a position controller, a velocity controller, an attitude controller, an angular velocity controller, and a lift feedback controller. It is assumed that the UAV is subjected to a constant horizontal wind and a vertical wind of magnitude 5 m / s, i.e., ||V||. h w ||=5m / s, V z w =5m / s; and the sensor system bandwidth meets the basic requirements of flight control and can measure lift with high precision, that is, the lift calculated by the model is used as the measured value in the simulation; a vertical circular trajectory with a radius of 1m, an angular frequency of π / 3rad / s, and a distance of 2m from the origin of the coordinate axis in the X-axis direction, a sloping circular trajectory with a radius of 2m and an angular frequency of π / 3rad / s, and a hind serpentine trajectory with model parameters a, b, and c of 2, 1, and 1 are selected for maneuver trajectory tracking. Simulation results show that under wind disturbance conditions, the multi-rotor UAV with lift feedback propulsion system exhibits higher control accuracy and stability, and can track maneuver trajectories with high precision, verifying the effectiveness of the proposed lift feedback control strategy.

[0118] See Figure 1 The diagram shows the underlying flight control framework of a rotary-wing UAV. First, the upper-level trajectory planner plans the desired position p. d and desired yaw angle ψ d In outer-loop control, the position controller receives the desired position p. d The rotorcraft drone provides the actual position p and outputs the desired velocity v. d The speed controller is fed into the output of the desired total lift f required by the rotorcraft UAV, based on the actual speed v. d And the expected roll angle φ d Desired pitch angle θ d In the inner-loop control, the attitude controller receives the desired yaw angle ψ. d Expected roll angle φ d Desired pitch angle θ d Combine the actual attitude angle Θ with the desired angular velocity ω. d The desired torque M is obtained by combining the actual angular velocity ω with the angular velocity controller. d Secondly, the hybrid control distributor obtained from the UAV dynamics model will determine the desired total lift f. d and desired torque M d The desired lift T required to be generated by the rotor of each axis power system d,i Subsequently, the sensor measures the lift generated by the rotor to obtain T. m,i The control input u is calculated by the lift closed-loop controller, and finally the electronic speed controller obtains the equivalent voltage U based on the motor speed control u. i To control the motor to produce the corresponding speed This drives the propeller to generate lift T, achieving closed-loop feedback control of lift.

[0119] This invention proposes a control method for rotary-wing unmanned aerial vehicles (UAVs) based on lift feedback. A dynamic model of a quadrotor UAV is established, ensuring a precise hybrid control distribution relationship from force and torque to rotor lift. A power system model of a multi-rotor UAV is also established, using motor throttle as input and rotor lift as output. Based on this model, an input-output linearized force closed-loop controller is designed to precisely control the output lift. This solves the problems of low control accuracy and poor flight stability of rotary-wing UAVs operating in windy environments or during maneuvering flight. Simulation results show that the proposed method can guarantee high-precision control and stability of rotary-wing UAVs in windy environments and during maneuvering flight.

[0120] The specific embodiments of the present invention have been described above with reference to the accompanying drawings. However, these descriptions should not be construed as limiting the scope of the present invention. The scope of protection of the present invention is defined by the appended claims. Any modifications based on the claims of the present invention are within the scope of protection of the present invention.

Claims

1. A control method for a rotary-wing unmanned aerial vehicle based on lift feedback, characterized in that, Includes the following steps: Step 1: Construct a rigid body dynamics model of the quadcopter UAV to map the total lift and torque of the UAV to the hybrid control distributor of the desired lift of each axis power system; Step 2: Establish a lift feedback control module for the UAV that includes lift measurement and closed-loop control, so as to perform closed-loop control of the single-axis power system via an electronic speed controller; Step 3: Establish a rotor lift aerodynamic model considering wind disturbance based on the momentum theorem and the blade element momentum theorem, and solve for the induced velocity to obtain the rotor lift T; Step 4: Based on the single-axis power system model of the UAV, a lift feedback controller is constructed by adopting the input-output feedback linearization method; Step 5: Based on the rigid body dynamics model of the quadcopter UAV, determine the desired lift T required by each rotor axis. d,i The lift feedback control module of the UAV enables the lift feedback controller to output a control law to the electronic speed controller in order to dynamically adjust the rotor lift.

2. The control method for a rotary-wing unmanned aerial vehicle based on lift feedback according to claim 1, characterized in that, Step 1 is as follows: Step 1.1: Construct the position dynamics and attitude dynamics model of the rotary-wing UAV: In the formula, p = [x, y, z] T Indicates position, v = [v x ,v y ,v z ] T Let represent velocity, g represent gravitational acceleration, m represent the mass of the drone, and e3 = [0, 0, 1]. T The unit vector representing the z-axis. Let Θ = [φ, θ, ψ] represent the rotation matrix from the body coordinate system to the inertial coordinate system. T The attitude angles of the UAV are represented by φ, θ, and ψ, where φ, θ, and ψ represent the roll angle, pitch angle, and yaw angle, respectively; ω = [ω x ,ω y ,ω z ] T Indicates the angular velocity of the machine body. This represents the moment of inertia of a rotary-wing drone. Represents the rate of change of attitude angle The relationship matrix between f and the body's rotational angular velocity ω, f and M = [M x M y M z ] T These represent the total lift and torque of the UAV, respectively. Step 1.2: Establish a model showing the relationship between the total lift f and torque M of the quadcopter UAV and the lift T of each rotor axis, i.e., the hybrid control allocation matrix is: In the formula, d is the distance from the geometric center of the machine body to the central axis of any motor, and c τ is a constant, representing an approximate relationship between lift and torque.

3. The control method for a rotary-wing unmanned aerial vehicle based on lift feedback according to claim 1, characterized in that, Step 2 is as follows: Step 2.1: Based on the desired position p d and desired yaw angle ψ d The desired total lift f is obtained through an inner-outer loop cascade PID controller. d and desired torque M d And through the mixing distributor, the desired total lift f d and desired torque M d The desired lift T mapped to each rotor axis d,i i = 1, 2, 3, 4, representing the axis numbers of the UAV; the outer ring includes the position controller and the velocity controller, and the inner ring includes the attitude controller and the angular velocity controller; Step 2.2: Establish the lift feedback module; The lift T generated by the rotor is directly measured using sensors. m,i A Kalman filter is used to reduce the influence of measurement noise in order to obtain the filtered lift value T. k,i Next, with T d,i and T k,i Using the control quantity u as the input and the control quantity u as the output, a lift feedback controller is constructed so that the electronic speed governor adjusts the equivalent voltage U according to the control quantity u. i Control the motor to generate speed This drives the propellers on each shaft to generate corresponding lift T. i .

4. The control method for a rotary-wing unmanned aerial vehicle based on lift feedback according to claim 1, characterized in that, Step 3 includes the following steps: Step 3.1: Construct the MT lift model and calculate the lift generated by the rotor based on the momentum balance of the rotor: In the formula, ρ represents air density, R represents rotor disk radius, and v i Indicates the induction velocity; and V represents the actual air velocity on the rotor. a Horizontal and vertical components; V s =V w -V is the airflow velocity passing through the rotor, V w V is the wind speed, and V is the drone's flight speed; and there is in and V s Horizontal and vertical components, For v i The vertical component; Combined with aerodynamic model Using the MT lift model, the lift coefficient is obtained: Step 3.2: Perform independent aerodynamic analysis on each blade element unit according to the BEMT (Beam-Momentum Theorem) to obtain the overall rotor lift coefficient: Where N b c represents the number of rotor blades. tip C is the chord length at the tip of the blade. lα Let θ be the slope of the lift curve. tip The blade tip pitch angle, This refers to the motor speed; The BEMT lift model is obtained as follows: Step 3.3: Equivalent to the lift coefficient in Step 3.1 and Step 3.2, solve the induced velocity using the combined equations to obtain the expression: Where C3=2ρπR 2 ; Step 3.4: Solve for the induced velocity v i The numerical solution, in v i >0 is used as a constraint condition, that is v corresponding to the minimum value i The desired induced velocity is: The obtained induced velocity v i The lift T of a single rotor can be calculated by substituting it into the BEMT lift model.

5. The control method for a rotary-wing unmanned aerial vehicle based on lift feedback according to claim 1, characterized in that, Step 4 is as follows: For the single-axis propulsion system model of the UAV, the input is the electronic speed controller control quantity u, the output is the lift y = T, and the state variable is the motor angular velocity x = ω. The goal is to make the output y of the UAV's single-axis propulsion system track the desired value y. d Expected value y d As a lifting T i Introducing error e = y d -y, whose derivative is Design the virtual control law as follows: in k0 is a constant; the output of the lift feedback controller is: C e C is the back electromotive force constant. m For electromagnetic torque constant and C e Equivalent, R m R is the equivalent resistance of the motor. e For the equivalent internal resistance of the electronically controlled switch, f m J is the coefficient of viscous friction between the motor and the load referred to the motor shaft. m Let α be the moment of inertia of the motor and load referred to the motor shaft, and M be the load torque. c The torque coefficient, β, has an approximately linear relationship with the lift force T, and represents the motor speed. The speed coefficient, U, has a linear relationship with the motor's angular velocity ω. e The input voltage of the brushless motor is obtained by the electronic speed controller linearly adjusting the control quantity u; R represents the rotor disk radius. The horizontal component representing the actual air velocity on the rotor. Represents the vertical component, v i Indicates the induced velocity. For V s The vertical component, V s =V w -V is the airflow velocity passing through the rotor; V w V represents wind speed, and V represents the drone's flight speed. For V s The horizontal component.

6. A control system for a rotary-wing unmanned aerial vehicle based on lift feedback, characterized in that, include: The rigid body dynamics model building module is used to build a rigid body dynamics model of a quadcopter UAV, so as to map the total lift and torque of the UAV to the hybrid control distributor of the desired lift of each axis power system; The UAV lift feedback control module is used to establish a UAV lift feedback control module that includes lift measurement and closed-loop control, so as to perform closed-loop control of the single-axis power system via an electronic speed controller; The rotor lift aerodynamic model building module is used to establish a rotor lift aerodynamic model considering wind disturbance based on the momentum theorem and the blade element momentum theorem, and solve for the induced velocity to obtain the rotor lift T. The lift feedback controller construction module is used to construct a lift feedback controller based on a single-axis UAV power system model by adopting an input-output feedback linearization method. The rotary-wing UAV control module is used to implement the rigid body dynamics model of a quadcopter UAV based on the desired lift T required by each rotor axis. d,i The lift feedback control module of the UAV enables the lift feedback controller to output a control law to the electronic speed controller in order to dynamically adjust the rotor lift.

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