A trajectory tracking method and system for an unmanned helicopter

Abstract

This invention discloses a trajectory tracking method and system for unmanned helicopters, relating to the field of UAV flight control technology. The method includes: at any moment during trajectory tracking, generating three-axis velocity control commands for the unmanned helicopter based on its desired ideal trajectory and actual position; processing the three-axis velocity control commands to obtain desired attitude angle commands; in an explicit model controller, acquiring the feedforward control quantity, total internal and external disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command, respectively; subtracting the total internal and external disturbance compensation quantity from the feedback compensation quantity to obtain the corresponding disturbance rejection compensation quantity; dividing the disturbance rejection compensation quantity by the control gain and adding it to the feedforward control quantity to obtain the corresponding control vector; and driving the actuators of the unmanned helicopter based on the control vector to achieve trajectory tracking. This method improves the trajectory tracking accuracy of unmanned helicopters.

Description

Technical Field

[0001] This application relates to the field of unmanned aerial vehicle (UAV) flight control technology, and in particular to a trajectory tracking method and system for unmanned helicopters. Background Technology

[0002] Unmanned helicopters, as aircraft capable of vertical takeoff and landing, hovering, and low-speed cruise, have broad application prospects in military reconnaissance, civilian plant protection, and power line inspection. However, helicopters possess inherent dynamic characteristics such as high-order nonlinearity, strong coupling, underactuation, and open-loop instability. Furthermore, they are susceptible to external environmental disturbances such as gusts and ground effects during flight, as well as internal model uncertainties such as load changes and aerodynamic parameter perturbations. This makes high-precision trajectory tracking control a highly challenging technical problem.

[0003] In recent years, Active Disturbance Rejection Control (ADRC) has attracted much attention due to its ability to suppress total disturbances without relying on an accurate model. However, while traditional ADRC is robust, its setpoint tracking is usually based on arranging transition processes, making it difficult to accurately reproduce specific flight dynamics qualities directly through parameter tuning when handling high-order complex maneuvers. On the other hand, Explicit Model Following Control (EMFC) can force the controlled object to follow an ideal reference model, thereby achieving excellent dynamic characteristics and decoupling performance. However, EMFC is very sensitive to model errors. Once aerodynamic disturbances or load changes occur during actual flight, causing model parameter drift, the tracking performance will drop sharply, resulting in low trajectory tracking accuracy for unmanned helicopters. Summary of the Invention

[0004] Therefore, it is necessary to provide a trajectory tracking method and system for unmanned helicopters to address the aforementioned technical problems. This method improves the trajectory tracking accuracy of unmanned helicopters.

[0005] The following technical solution is adopted in this specification: This specification provides a trajectory tracking method for unmanned helicopters, including: At any moment during unmanned helicopter trajectory tracking, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter, a three-axis speed control command for the unmanned helicopter is generated; the three-axis speed control command includes the desired longitudinal speed, the desired lateral speed, and the desired vertical speed. The three-axis speed control command is processed to obtain the desired attitude angle command; the desired attitude angle command includes the desired pitch angle command, the desired roll angle command, and the desired vertical speed command. In the explicit model controller, the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical speed command, and yaw rate command are obtained respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and then added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical speed. The actuators of the unmanned helicopter are driven by controlling pitch, roll, yaw, and lift to achieve trajectory tracking.

[0006] Optionally, the feedforward control quantity, total internal and external disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical speed command, and yaw rate command are obtained respectively, specifically including: For any one of the desired attitude angle commands, such as the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command, the desired attitude angle command is input into the preset explicit model for calculation to obtain the ideal reference state. The actual flight status of unmanned helicopters is obtained based on helicopter flight dynamics models; The actual flight state of the unmanned helicopter is compared with the ideal reference state output by the explicit model to obtain the state tracking error of the system. By using forward gain, forward gain diagonal matrix, decoupling matrix, and control matrix, the state tracking error signal is proportionally gained, integrated, and superimposed to obtain the feedforward control quantity corresponding to the desired attitude angle command. The ideal reference state is smoothed and differentiated using LTD to obtain smoothed position and smoothed velocity commands. The actual flight state and the control input from the previous moment are input into the Linear Extended State Observer (LESO) to estimate the system state and observe the total internal and external disturbance compensation in real time. Calculate the error between the smooth position command and the smooth speed command and the estimated state obtained by LESO, and input the error into the linear state error feedback control law LSEF to obtain the feedback compensation amount.

[0007] Optionally, the feedforward control quantity corresponding to the desired attitude angle command is obtained by proportional gain, integration, and superposition of the state tracking error signal through the forward gain, forward gain diagonal matrix, decoupling matrix, and control matrix, specifically including: The rate signal is obtained by proportionally increasing the forward gain of the state tracking error signal; The difference between the rate signal and the actual rate signal is defined as the rate error; The rate error is processed by proportional gain processing using the forward gain diagonal matrix and the decoupling matrix to obtain the first signal; The first signal is integrated through a control matrix that includes an integral function to obtain the second signal; The first and second signals are superimposed to obtain the feedforward control quantity corresponding to the desired attitude angle command.

[0008] Optionally, the formula for calculating the control vector is: ; in, The control vector at the current moment, , To control pitch, To control the roll, To control lift, To control the course, This is the feedforward control variable for the explicit model. To provide feedback on compensation amount, This represents the total compensation amount for internal and external disturbances. To control the gain; The formula for calculating the feedback compensation amount is: ; in, Angle estimates calculated for LESO. and Both represent the tracking error between the ideal trajectory of the explicit model and the system state estimated by LESO. , , Angular velocity estimates calculated for LESO For error feedback control, the proportional gain The differential gain for error feedback control; Feedforward control quantity The calculation formula is: ; in, This is the feedforward control quantity. and All are explicit model control matrices. e This refers to the rate error in the explicit model control loop.

[0009] Alternatively, the formula corresponding to the helicopter flight dynamics model is: ; in, The forward flight speed of the unmanned helicopter. The lateral velocity of the unmanned helicopter. The vertical velocity of the unmanned helicopter. For unmanned helicopters to circle x Angular velocity of the shaft rotation, Unmanned helicopters circle y Angular velocity of the shaft rotation, For unmanned helicopters to circle z Angular velocity of the shaft rotation, Circling the fuselage of the unmanned helicopter x Moment of inertia of the shaft Circling the fuselage of the unmanned helicopter y Moment of inertia of the shaft Circling the fuselage of the unmanned helicopter z Moment of inertia of the shaft The pitch angle of the unmanned helicopter around its body axis. The roll angle of the unmanned helicopter around its body axis. This is the yaw angle of the unmanned helicopter around its body axis. Forward acceleration of the body, This refers to the lateral acceleration of the aircraft. The vertical acceleration of the body. For roll acceleration, For pitch acceleration, Yaw acceleration, This represents the rate of change of the roll angle. The rate of change of pitch angle, The rate of change of yaw angle. The force generated by the main rotor on the airframe x Components on the axis, The force generated by the fuselage in the fuselage x Components on the axis, The force generated by the main rotor on the airframe y Components on the axis, The force generated by the fuselage in the fuselage y Components on the axis, The force generated by the tail rotor on the fuselage y Components on the axis, The force generated by the main rotor on the airframe z Components on the axis, The force generated by the fuselage in the fuselage z Components on the axis, The rolling torque generated by the main rotor The rolling torque generated by the tail rotor It is the acceleration due to gravity. The anti-torsional torque of the main rotor, The yaw moment generated by the tail rotor m The mass of the unmanned helicopter.

[0010] Optionally, when the object processed in the attitude loop is a pitch angle command, an ideal reference model that meets the flight quality specifications is set; the ideal reference model is constructed in the form of an explicit model; the formula corresponding to the explicit model is: ; in, For the desired pitch angle state, For natural frequency, Input commands for the vertical channel. The damping ratio; When the object processed in the attitude loop is a pitch angle command, the dynamic equation of the pitch channel is: ; in, The rate of change of pitch acceleration, The total disturbance experienced by the system For the control signals output to the helicopter, To control the gain; When the object processed in the attitude loop is a pitch angle command, the corresponding calculation formula for the Linear Extended State Observer (LESO) is: ; in, To reveal the tracking error between the ideal pitch angle of the model and the LESO angle estimate, The rate of change of the estimated angle for LESO. The rate of change of the estimated angular velocity calculated for LESO. The LESO estimate of the rate of change of total disturbance to the pitch channel. To correct the angle estimation error for the observer gain, To correct the angular velocity estimation error for the observer gain, Correct the total disturbance estimation error for the observer gain; When the object processed in the attitude loop is a pitch angle command, the generated control quantity is: ; in, For controlling the pitch at the current moment, This is the feedforward control quantity for the explicit model. For the ideal pitch angle, The ideal pitch angular velocity.

[0011] Optionally, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter, three-axis speed control commands for the unmanned helicopter are generated, specifically including: Obtain the desired ideal trajectory and the actual position of the unmanned helicopter in the ground coordinate system; the desired ideal trajectory is a three-dimensional coordinate vector. The desired trajectory of the unmanned helicopter and its actual position are compared. x Input the direction difference to x The desired lateral velocity is obtained using the directional linear active disturbance rejection controller XLADRC. The desired trajectory of the unmanned helicopter and its actual position are compared. y Input the direction difference to y The desired longitudinal velocity is obtained using the YLADRC (Directional Linear Active Disturbance Rejection Controller). The desired trajectory of the unmanned helicopter and its actual position are compared. z Input the direction difference to z The desired vertical velocity is obtained using the directional linear active disturbance rejection controller ZLADRC. The desired lateral velocity, desired longitudinal velocity, and desired vertical velocity are defined as the three-axis speed control commands.

[0012] Optionally, the three-axis speed control command is processed to obtain the desired attitude angle command, specifically including: Obtain the three-axis speed control commands of the unmanned helicopter; the three-axis speed control commands include the desired lateral speed, desired longitudinal speed, and desired vertical speed; Obtain the actual speed of the unmanned helicopter; the actual speed includes the actual longitudinal speed, the actual lateral speed, and the actual vertical speed. The difference between the desired lateral velocity and the actual lateral velocity is used to obtain the lateral velocity tracking error. The difference between the desired longitudinal speed and the actual longitudinal speed is used to obtain the longitudinal speed tracking error. The difference between the desired longitudinal velocity and the actual longitudinal velocity is used to obtain the vertical velocity tracking error. The longitudinal velocity tracking error, lateral velocity tracking error, and vertical velocity tracking error are input to the speed controller to generate the desired pitch angle, desired roll angle, and desired vertical velocity. The desired pitch angle, desired roll angle, and desired vertical velocity are determined as the desired attitude angle commands for the unmanned helicopter.

[0013] Optionally, the formula for calculating the yaw rate command is: ; in, The yaw rate command, This is the initial forward velocity of the helicopter when it is in a horizontal forward flight state. The lateral speed generated during heading coordination control. This represents the current flight speed of the unmanned helicopter.

[0014] A trajectory tracking system for an unmanned helicopter includes an attitude loop, a velocity loop, and a position loop; The position loop is used to generate three-axis speed control commands for the unmanned helicopter at any moment during trajectory tracking, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter. The three-axis speed control commands include the desired longitudinal speed, the desired lateral speed, and the desired vertical speed. The speed loop is used to process the three-axis speed control commands to obtain the desired attitude angle commands; the desired attitude angle commands include the desired pitch angle command, the desired roll angle command, and the desired vertical speed command. The attitude loop is used in the explicit model controller to obtain the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command, respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical velocity.

[0015] The above-mentioned technical solutions adopted in this specification can achieve the following beneficial effects: In the trajectory tracking method for unmanned helicopters provided in this specification, at any moment during trajectory tracking, a three-axis velocity control command for the unmanned helicopter is generated based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and multiple position loop controllers. The three-axis velocity control command is input to the velocity loop for velocity control processing to obtain the desired attitude angle command. In the explicit model controller, the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command are obtained respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical velocity.

[0016] Based on the desired ideal trajectory in the ground coordinate system, and combined with the collaborative action of multiple position loop controllers, the three-axis speed control commands of the unmanned helicopter are accurately generated, ensuring the matching degree between the speed commands and the ideal trajectory, and reducing position tracking deviation from the source. The desired pitch angle command, desired roll angle command, desired vertical speed command and yaw rate command are controlled independently, and the control strategy can be optimized according to the control requirements of different attitude parameters, improving the accuracy of the control of each attitude parameter, and thus improving the trajectory tracking accuracy of the unmanned helicopter. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 This is a block diagram of the overall structure of the unmanned helicopter trajectory tracking control system proposed in this invention; Figure 2 This is a schematic diagram of a trajectory tracking method for an unmanned helicopter as described in this specification. Figure 3 The basic principle diagram of explicit model tracking control (EMFC) provided by this invention; Figure 4 A detailed structural diagram of the inner loop attitude controller (LADRC-EMFC) provided by the present invention; Figure 5 The simulation diagrams comparing the attitude response of the method of the present invention and the single EMFC control method under disturbance are shown in Figure 1. (a) Figure 2 shows the longitudinal channel disturbance response, (b) Figure 3 shows the lateral channel disturbance response, (c) Figure 4 shows the yaw channel disturbance response, and (d) Figure 5 shows the vertical channel disturbance response. Figure 6 The following figures illustrate the tracking effect of the three-dimensional figure-eight spiral ascent trajectory of the unmanned helicopter under the control of the method of the present invention: (a) Figure 3 shows the three-dimensional response diagram of the unmanned helicopter flight trajectory; (b) Figure 4 shows the projection view of the unmanned helicopter flight trajectory on the horizontal plane (XY plane); and (c) Figure 5 shows the response curve of the unmanned helicopter flight trajectory in the vertical direction (height-time). Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.

[0020] Devices such as desktop computers, servers, and laptops are capable of executing the solutions described in this manual. For ease of explanation, the following description will focus on servers as the primary execution method.

[0021] Existing flight control methods mainly include classical proportional-integral-derivative (PID) control and modern control theory methods, such as linear quadratic regulator control (LQR) and H-infinity control (H∞). PID control has a simple structure, but parameter tuning is extremely difficult when dealing with multivariable, strongly coupled helicopter systems, often requiring a trade-off between response speed and stability, and its disturbance rejection capability is limited. Linear quadratic regulator control (LQR) relies on an accurate linearized mathematical model; when the helicopter deviates from its equilibrium operating point or the model parameters change, the control performance deteriorates significantly.

[0022] This invention deeply integrates the powerful disturbance compensation capability of LADRC with the excellent command tracking capability of EMFC, resulting in high tracking accuracy in complex maneuver trajectory tracking tasks of unmanned helicopters.

[0023] An unmanned helicopter trajectory tracking system based on active disturbance rejection and explicit model tracking includes an attitude loop, a velocity loop, and a position loop. The position loop generates three-axis velocity control commands for the unmanned helicopter at any given moment during trajectory tracking, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter. These three-axis velocity control commands include desired longitudinal velocity, desired lateral velocity, and desired vertical velocity. The velocity loop processes these three-axis velocity control commands to obtain desired attitude angle commands, which include desired pitch angle and desired roll angle commands. The desired vertical velocity command; the attitude loop, used in the explicit model controller, to obtain the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command, respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical velocity.

[0024] Specifically, a trajectory tracking system for an unmanned helicopter adopts a hierarchical structure from the inside out, sequentially constructing an attitude loop (inner loop), a velocity loop (middle loop), and a trajectory loop (outer loop). The core of this invention lies in the design of the attitude controller in the attitude loop, which employs a strategy combining Linear Active Disturbance Rejection Control (LADRC) and Explicit Model Following Control (EMFC).

[0025] As an ideal response model, EMFC designs control laws that conform to a specific transfer function (ideal model). Based on this, the Linear Extended State Observer (LESO) of the inner loop (attitude loop) LADRC estimates and cancels out the system's model uncertainties, coupling terms, and external disturbances as a total disturbance.

[0026] Dimensionality reduction design of the outer loop (trajectory loop): Thanks to the strong decoupling characteristics of the inner loop, the outer loop trajectory tracking no longer requires a complex multiple-input multiple-output (MIMO) design, but is simplified to multi-channel independent LADRC control, which greatly reduces the computing power requirements for engineering implementation.

[0027] Figure 1 This is a block diagram of the overall structure of the unmanned helicopter trajectory tracking control system proposed in this invention, as shown below. Figure 1 As shown, the controlled object model takes a certain type of unmanned helicopter as an example. The linearized state equation of the unmanned helicopter is: Among them, the state vector Control input Corresponding to longitudinal periodic pitch Lateral periodic pitch Total distance and tail rotor pitch .

[0028] Outer loop: Trajectory tracking loop.

[0029] Input signal: The input to the outer loop is the desired ideal trajectory in the ground coordinate system, usually represented as a three-dimensional position coordinate vector. The system will determine the desired trajectory Current actual position of the helicopter By comparison, the position tracking error is obtained. e This error is input to the position loop controller. Figure 1 XLADRC, YLADRC, and ZLADRC are among them.

[0030] Output signals: The outer loop outputs three-axis speed control commands, which include the desired longitudinal speed. u c Desired lateral velocity v c and desired vertical velocity w c The three-axis speed control commands flow to the central loop.

[0031] Middle loop: speed control loop.

[0032] Input signal: The middle ring receives the three-axis speed control command from the outer ring.

[0033] Output signals: The output of the middle loop is the desired attitude angle command. The desired pitch angle command is obtained from the longitudinal velocity error, the desired roll angle command is obtained from the lateral velocity error, and the desired vertical velocity command is obtained from the vertical velocity error.

[0034] Inner loop: Attitude control loop.

[0035] Input signals: Receive attitude and desired attitude angle commands from the central loop.

[0036] Output signals: The inner loop outputs four physical control quantities, which directly drive the actuators of the unmanned helicopter. These control quantities constitute the control vector. .

[0037] During each clock cycle interrupt, the processor sequentially collects sensor data, calculates the outer loop error, updates the middle loop instructions, solves the inner loop control law, and finally outputs the control signal.

[0038] Under the baseline state of 22m / s, a common cruising speed for unmanned helicopters, small disturbance linearization is performed. Considering the strong coupling of helicopters, traditional single-loop designs are difficult to meet the requirements.

[0039] Speed ​​control loop design: Due to the good decoupling and dynamic and static tracking characteristics of the inner loop composite controller, the design of the external loop control law of the originally complex multi-input and multi-output system can be simplified to a single-input single-output system.

[0040] External loop trajectory tracking design: simplifying 3D trajectory tracking to X , Y , Z The problem of three-way independent single-input single-output (SISO) control is solved by adopting a multi-channel LADRC strategy to generate speed commands based on position errors, thereby achieving accurate tracking of complex trajectories.

[0041] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0042] Figure 2 This is a schematic diagram of a trajectory tracking method for an unmanned helicopter as described in this specification, which specifically includes the following steps: S201: At any moment during unmanned helicopter trajectory tracking, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter, generate three-axis speed control commands for the unmanned helicopter; the three-axis speed control commands include the desired longitudinal speed. u c Desired lateral velocity v c and desired vertical velocity w c .

[0043] In an exemplary embodiment, a three-axis velocity control command for the unmanned helicopter is generated based on the desired ideal trajectory and the actual position of the unmanned helicopter in a ground coordinate system. Specifically, this includes: obtaining the desired ideal trajectory and the actual position of the unmanned helicopter in a ground coordinate system; the desired ideal trajectory is a three-dimensional coordinate vector; and... x Input the direction difference to x The directional linear active disturbance rejection controller (XLADRC) is used to obtain the desired lateral velocity; the desired ideal trajectory of the unmanned helicopter and its actual position are then compared. y Input the direction difference to y The directional linear active disturbance rejection controller (YLADRC) is used to obtain the desired longitudinal velocity; the desired ideal trajectory of the unmanned helicopter and its actual position are then compared. z Input the direction difference to z The directional linear active disturbance rejection controller ZLADRC obtains the desired vertical velocity; the desired lateral velocity, desired longitudinal velocity, and desired vertical velocity are then determined as the three-axis velocity control commands.

[0044] S202: Process the three-axis speed control command to obtain the desired attitude angle command; the desired attitude angle command includes the desired pitch angle command, the desired roll angle command, and the desired vertical speed command.

[0045] In an exemplary embodiment, the three-axis speed control command is processed to obtain the desired attitude angle command. Specifically, this includes: acquiring the three-axis speed control command of the unmanned helicopter; the three-axis speed control command includes the desired lateral speed, desired longitudinal speed, and desired vertical speed; acquiring the actual speed of the unmanned helicopter; the actual speed includes the actual longitudinal speed, actual lateral speed, and actual vertical speed; taking the difference between the desired lateral speed and the actual lateral speed to obtain the lateral speed tracking error; taking the difference between the desired longitudinal speed and the actual longitudinal speed to obtain the longitudinal speed tracking error; taking the difference between the desired longitudinal speed and the actual longitudinal speed to obtain the vertical speed tracking error; and inputting the longitudinal speed tracking error, lateral speed tracking error, and vertical speed tracking error to the speed controller to generate the desired pitch angle and desired roll angle. ϕ c The desired vertical velocity and desired pitch angle, desired roll angle and desired vertical velocity are determined as the desired attitude angle command for the unmanned helicopter.

[0046] S203: In the explicit model controller, the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical speed command, and yaw rate command are obtained respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical speed.

[0047] In an exemplary embodiment, the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command are obtained respectively. Specifically, this includes: for any desired attitude angle command among the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command, the desired attitude angle command is input into a preset explicit model for calculation to obtain an ideal reference state; the actual flight state of the unmanned helicopter is obtained based on the helicopter flight dynamics model; and the actual flight state of the unmanned helicopter is compared with the ideal reference state output by the explicit model to obtain the system's state tracking. Error; the state tracking error signal is proportionally gained, integrated, and superimposed using forward gain, forward gain diagonal matrix, decoupling matrix, and control matrix to obtain the feedforward control quantity corresponding to the desired attitude angle command; the ideal reference state is smoothed and differentiated using LTD to obtain the smoothed position command and smoothed velocity command; the actual flight state and the control quantity from the previous moment are input into the linear extended state observer (LESO) to estimate the system state and observe the total internal and external disturbance compensation quantity in real time; the error between the smoothed position command and smoothed velocity command and the estimated state obtained by LESO is calculated, and the error is input into the linear state error feedback control law (LSEF) to obtain the feedback compensation quantity.

[0048] Specifically, when the object processed in the attitude loop is a pitch angle command, an ideal reference model that meets the flight quality specifications is set; the ideal reference model is constructed in the form of an explicit model; the formula corresponding to the explicit model is formula (1): (1); in, For the desired pitch angle state, For natural frequency, Input commands for the vertical channel. Let the damping ratio be . Take the damping ratio as . natural frequency Based on mobility requirements The value is constant (e.g., rad / s). The model receives instructions. Output the desired pitch angle state and its derivative.

[0049] Specifically, Figure 3 A detailed structural diagram of the inner loop attitude controller (LADRC-EMFC) provided by this invention is shown below. Figure 3As shown, the final control vector is generated by using explicit model tracking error and disturbance compensation. The system mainly includes an explicit model, a tracking differentiator (LTD), a linear state error feedback module (LSEF), an explicit model-following control system (MFCS), actuators, a helicopter flight dynamics model, and a linear extended state observer (LESO).

[0050] The explicit model controller includes forward gain G5, state feedback compensation signal G2, decoupling matrix G3 and through gain matrix G4, tracking differentiator LTD, linear state error feedback LSEF, explicit model control system MFCS, actuators, linear extended state observer LESO and helicopter flight dynamics model.

[0051] Based on the aerodynamic analysis of components such as the rotor, tail rotor, and fuselage, nonlinear dynamic equations for the unmanned helicopter are established and linearized under a baseline state to obtain a state-space model of the unmanned helicopter.

[0052] In helicopter modeling, the aerodynamic forces of each key component, including the rotor, tail rotor, fuselage, horizontal stabilizer, and vertical stabilizer, were calculated. Based on the established component aerodynamic models, combined with the force analysis of the fuselage and the mathematical relationship between Euler angles and angular rates, the nonlinear dynamic equation of the helicopter was constructed as formula (2):

[0053] (2); in, The forward flight speed of the unmanned helicopter. The lateral velocity of the unmanned helicopter. The vertical velocity of the unmanned helicopter. For unmanned helicopters to circle x Angular velocity of the shaft rotation, Unmanned helicopters circle y Angular velocity of the shaft rotation, For unmanned helicopters to circle z Angular velocity of the shaft rotation, Circling the fuselage of the unmanned helicopter x Moment of inertia of the shaft, Circling the fuselage of the unmanned helicopter y Moment of inertia of the shaft, Circling the fuselage of the unmanned helicopter z Moment of inertia of the shaft, The pitch angle of the unmanned helicopter around its body axis. The roll angle of the unmanned helicopter around its body axis. This is the yaw angle of the unmanned helicopter around its body axis. Forward acceleration of the body, This refers to the lateral acceleration of the aircraft. The vertical acceleration of the body. For roll acceleration, For pitch acceleration, Yaw acceleration, This represents the rate of change of the roll angle. The rate of change of pitch angle, The rate of change of yaw angle. The force generated by the main rotor on the airframe x Components on the axis, The force generated by the fuselage in the fuselage x Components on the axis, The force generated by the main rotor on the airframe y Components on the axis, The force generated by the fuselage in the fuselage y Components on the axis, The force generated by the tail rotor on the fuselage y Components on the axis, The force generated by the main rotor on the airframe z Components on the axis, The force generated by the fuselage in the fuselage z Components on the axis, The rolling torque generated by the main rotor The rolling torque generated by the tail rotor It is the acceleration due to gravity. The anti-torsional torque of the main rotor, The yaw moment generated by the tail rotor m The mass of the unmanned helicopter.

[0054] In an exemplary embodiment, the state tracking error signal is proportionally gained, integrated, and superimposed using a forward gain, a forward gain diagonal matrix, a decoupling matrix, and a control matrix to obtain the feedforward control quantity corresponding to the desired attitude angle command. Specifically, this includes: proportionally gaining the state tracking error signal using a forward gain to obtain a rate signal; determining the difference between the rate signal and the actual rate signal as the rate error; proportionally gaining the rate error using the forward gain diagonal matrix and the decoupling matrix to obtain a first signal; integrating the first signal using a control matrix that includes integration to obtain a second signal; and superimposing the first signal and the second signal to obtain the feedforward control quantity corresponding to the desired attitude angle command.

[0055] Specifically, Figure 4 The basic principle diagram of Explicit Model Tracking Control (EMFC) provided by this invention is as follows: Figure 4As shown, for helicopter attitude control, the desired response is typically designed as a second-order linear system to meet the ADS-33E-PRF standard. As the controlled object, the desired attitude angle commands are input into the explicit model in terms of lateral, longitudinal, and yaw directions. This is the output of the explicit model, representing the ideal reference state of the controlled object. Control method adjustment steps: The external loop feedback quantity passes through... Configure as pitch variable and roll attitude variables , with the ideal attitude signal of the explicit model Formation error The internal loop feedback quantity passes through Configured as three-axis angular rate and ground velocity variables .

[0056] For any desired attitude angle command, the desired attitude angle command is input into the preset explicit model for calculation to obtain the ideal reference state. Figure 4 In (The actual flight state of the unmanned helicopter is obtained based on the helicopter flight dynamics model) The actual flight status of the unmanned helicopter Ideal reference state output by explicit model By comparison, the state tracking error of the system is obtained. ; through forward gain Forward gain diagonal matrix R, decoupling matrix Control matrix For state tracking error signals By performing proportional gain, integration, and superposition, the feedforward control quantity corresponding to the desired attitude angle command is obtained. The ideal reference state is smoothed and differentiated using LTD to obtain the smoothed position command. and smooth speed command The actual flight state and the control input from the previous moment are input into the Linear Extended State Observer (LESO) to estimate the system state and observe the total internal and external disturbance compensation in real time. ; Calculate smooth position command and smooth speed command The error between the estimated state obtained from LESO and the error is input into the linear state error feedback control law LSEF to obtain the feedback compensation amount. The core function of the explicit model is to generate an ideal system state trajectory based on manipulation commands. It defines the desired quality of the system. The specific control flow is as follows: state tracking error. pass Convert to rate signal , and the actual rate signal The difference forms the rate error The rate error passes through the forward gain diagonal matrix R and the control matrix containing the integral action. and Processing and generating actuator signals for driving the control surfaces. u Based on this control architecture, the control parameters are configured to eliminate rate tracking error within a single sampling period, thereby enabling the actual flight state of the helicopter to quickly track the theoretical output of the explicit model.

[0057] The formula for calculating the yaw rate command is formula (3): (3); in, The yaw rate command. This is the initial forward velocity of the helicopter when it is in a horizontal forward flight state. The lateral speed generated during heading coordination control. This represents the current flight speed of the unmanned helicopter.

[0058] An ideal second-order reference model conforming to flight quality specifications is designed by using an explicit model tracking control EMFC controller. Based on this, the linear extended state observer in LADRC is used to treat unmodeled dynamics, parameter perturbations, inter-channel coupling torques, and external wind disturbances in the helicopter system as a unified total disturbance. A tracking control law is designed to ensure that the actual helicopter output, after disturbance compensation, accurately tracks the output of this ideal reference model, thereby achieving high-performance attitude control and channel decoupling.

[0059] The four control commands are associated with four key flight states: pitch angle, roll angle, vertical velocity, and yaw rate. For each channel, the controller outputs precise tracking commands and suppresses coupling effects from other channels (treating them as disturbances), thus keeping channels without command input calm. Ultimately, by combining independent tracking and calming for each channel, the goal of decoupled control is achieved.

[0060] The system at the current sampling time To acquire the desired command signal issued by the upper-level guidance circuit or remote controller. (e.g., desired pitch angle), while simultaneously collecting the helicopter's actual flight status through onboard sensors. (e.g., actual pitch angle).

[0061] Output of actual sensor and the control vector of the previous time step Input a Linear Extended State Observer (LESO). LESO calculates the system's state estimate in real time. (Angle estimation) (Angular velocity estimation), and observe the total disturbance estimate including unmodeled dynamics and external wind disturbance. .

[0062] When the object processed in the attitude loop is a pitch angle command, the dynamic equation of the pitch channel is (4): (4); in, The rate of change of pitch acceleration, The total disturbance experienced by the system For the control signals output to the helicopter, To control the gain.

[0063] When the object processed in the attitude loop is a pitch angle command, the corresponding calculation formula for the Linear Extended State Observer (LESO) is (5): (5); in, To show the tracking error between the ideal pitch angle of the model and the LESO angle estimate, The rate of change of the estimated angle for LESO was calculated. The rate of change of the estimated angular velocity calculated for LESO. The LESO estimate of the rate of change of total disturbance to the pitch channel. To correct the angle estimation error for the observer gain, To correct the angular velocity estimation error for the observer gain, The total disturbance estimation error is corrected for the observer gain.

[0064] The tracking error between the explicit model's ideal trajectory and the LESO estimated state is calculated using formulas (6) and (7): (6); (7); The error is input into the linear state error feedback (LSEF) control law, and the formula for calculating the feedback compensation is formula (8): (8); in, Angle estimates calculated for LESO. and Both represent the tracking error between the ideal trajectory of the explicit model and the system state estimated by LESO. , , Angular velocity estimates calculated for LESO For error feedback control, the proportional gain This is the differential gain for error feedback control.

[0065] Feedforward control quantity The calculation formula is formula (9): (9); in, This is the feedforward control variable. and All are explicit model control matrices. e This refers to the rate error in the explicit model control loop.

[0066] Final control quantity The control vector at the current moment is composed of three parts: the feedforward quantity plus the feedback quantity, and then the disturbance compensation quantity is subtracted. The formula for calculating the control vector at the current moment is formula (10): (10); in, The control vector at the current moment, , To control pitch, To control the roll, To control lift, To control the course, This is the feedforward control variable for the explicit model. To provide feedback on compensation amount, This represents the total compensation amount for internal and external disturbances. To control the gain.

[0067] The calculated total control quantity Amplitude limiting protection is performed, and then the signal is sent to the helicopter's actuation system to drive the helicopter to change its flight attitude and complete the control task for the current cycle.

[0068] When the object processed in the attitude loop is the pitch angle, the formula for generating the control vector is formula (11): (11); Among them, among them, For controlling the pitch at the current moment, This is the feedforward control quantity for the explicit model. For the ideal pitch angle, For the ideal pitch angular velocity, in this control law, The term directly cancels out the nonlinearity and disturbances of the system, making the closed-loop system approximately a double-integral system. This ensures that the system closely follows the ideal model. The trajectory.

[0069] S204: An actuator that drives the unmanned helicopter to achieve trajectory tracking based on pitch control, roll control, yaw control, and lift control.

[0070] In an exemplary embodiment, to verify the anti-interference performance of the inner loop attitude control and evaluate the impact of modeling errors and external disturbances on helicopter flight attitude control, the following two scenarios are designed for simulation analysis of the system: Scenario 1: Under the condition that the control matrix G remains unchanged, the helicopter model parameters are perturbed by ±20%, and the state matrix in the object is set to A1=0.8A and the control matrix is ​​set to B1=0.8B.

[0071] Scenario 2: Helicopters are susceptible to external disturbances in flight control. To test the anti-interference performance of the helicopter flight control, a 100 Hz disturbance signal with an average amplitude of ±2° is introduced into the longitudinal and lateral channels of the attitude control loop; a 100 Hz yaw disturbance signal with an average amplitude of ±2° / s is introduced into the yaw channel; and a 100 Hz vertical disturbance signal with an average amplitude of ±2 m / s is introduced into the collective pitch channel.

[0072] Figure 5 Simulation comparison of attitude response under disturbance between the method of this invention and the single EMFC control method, as shown in the figure. Figure 5 As shown, the composite controller exhibits excellent anti-interference capability. By observing the curves, it can be found that the output curve of the traditional control algorithm shows more obvious jitter during the disturbance stage.

[0073] Figure 5 The figure shows a comparison of the attitude control performance of the system under strong disturbances (model parameter perturbation ±20% and external wind disturbance). (a) The figure shows the longitudinal channel disturbance response, (b) The figure shows the lateral channel disturbance response, (c) The figure shows the yaw channel disturbance response, and (d) The figure shows the vertical channel disturbance response.

[0074] The stability of the designed composite controller was verified.

[0075] Parameter tuning: To simplify tuning, the observer poles are usually placed at the same location. (Observer bandwidth) is given by formula (12): (12); in, For observer gain, This represents the observer bandwidth.

[0076] The observation error is defined by formula (13): (13); in, , , These are the angles, angular velocities, and total disturbance estimates calculated by LESO. , , These represent the actual angle, actual angular velocity, and actual total disturbance, respectively. For observation error, i =1,2,3.

[0077] Subtracting the system equations from the LESO equations, we obtain the observation error dynamics equation as formula (14): (14); For ease of analysis, a scaling transformation is introduced as formula (15): (15); Substituting into the above equation and rearranging, we obtain the scaled error state equation as formula (16): (16); Among them, the system matrix of the observation error system Input matrix because The selection makes This is the Hurwitz stable matrix.

[0078] Phase 1: Proof of LESO convergence.

[0079] Assumption 1: Total disturbance It is differentiable, and its derivative is bounded, meaning there exists a constant. , making This makes sense in the physical world because the forces acting on a helicopter will not change abruptly at an infinite rate.

[0080] The Lyapunov function is constructed as formula (17): (17); in, It is a positive definite symmetric matrix that satisfies the Lyapunov equation. .

[0081] right Differentiation yields formula (18): (18); Scaling using inequalities yields formula (19): (19); In order to It needs to satisfy formula (20): (20); Conclusion: Observational error Ultimately, it will converge to a sphere centered at the origin. The radius of this sphere is... Proportional to the observer bandwidth It is inversely proportional to the cube. As long as Large enough, observation error It can be any size.

[0082] Phase Two: Proof of Closed-Loop Tracking Stability.

[0083] Define the tracking error E1 as Equation (21): (twenty one); The dynamics of the closed-loop system are derived as formula (22): (twenty two); in, y This represents the actual output state of the unmanned helicopter. y m For ideal output conditions, k p , k d The controller gain is for Linear State Error Feedback (LSEF).

[0084] The tracking error equation is derived as formula (23): (twenty three); Constructing the closed-loop tracking error vector The above equation can be rewritten in standard state space matrix form (24) by reducing its order: (twenty four); Among them, the closed-loop system matrix , Observation error transfer matrix .

[0085] Due to controller parameters Select to make Stable (eigenvalues ​​in the left half-plane), and input terms It is proved by LESO that the system is bounded. According to the Input-to-State Stability (ISS) theory, the state of a linear system under bounded input excitation is also bounded.

[0086] Specific proof: The Lyapunov functions are constructed as shown in formulas (25) and (26): (25); (26); because Follow It increases and tends to 0, therefore exist The value must be negative over a large region. This proves the tracking error of the closed-loop system. It is uniformly ultimately bounded (UUB). And as... When the error limit approaches zero, asymptotic tracking is achieved.

[0087] In one exemplary embodiment, since the inner loop has achieved decoupling of each channel, the outer loop can be simplified into a single-input single-output system. The desired time-varying ideal trajectory is planned in the ground coordinate system using a real-time trajectory generator. The guidance system compares this trajectory with the actual flight trajectory. By comparison, the guidance error is obtained. After the error is calculated by the guidance law, it is mapped to the body coordinate system by the coordinate transformation matrix, generating three-axis velocity control commands. .

[0088] Define position error E p For formula (27): (27); in, , , This represents the ideal trajectory position for the unmanned helicopter. x , y , z This indicates the actual location of the unmanned helicopter.

[0089] A LADRC controller is used to convert the position error into the desired speed command. For example, in the X-axis direction: a linear tracking differentiator (LTD) is used to arrange the transition process of position commands, avoiding actuator saturation caused by sudden command changes.

[0090] The linear tracking differentiator (LTD) provides a smooth reference trajectory for the system and extracts the differential signal from it, in the form of formula (28): (28); in, r It is the speed factor that determines the tracking speed. t Indicates the number of samples. x For input signal, It is the firstt The tracking output signal of the step, It is the first t The tracking differential output signal of the step, h This is the sampling step size.

[0091] The expression for LSEF is formula (29): (29); in, and It is the controller gain, which is determined by the controller bandwidth. and Provides real-time estimated system state information for LESO.

[0092] Finally obtained x The speed control command in the axial direction is formula (30): (30).

[0093] Figure 6 The image provided by the present invention shows the tracking effect of the three-dimensional figure-eight spiral ascent trajectory of an unmanned helicopter under the control of the present invention, as shown in the figure. Figure 6 As shown in the figure, the unmanned helicopter trajectory tracking effect diagram shows that the UAV quickly converges to the desired trajectory curve from the initial starting point, and can always coincide with the desired trajectory in the subsequent simulation process, with good tracking effect.

[0094] Figure 6 Figure (a) shows the 3D response of the unmanned helicopter's flight trajectory. The blue dashed line represents the preset desired trajectory, and the red solid line represents the actual flight trajectory of the unmanned helicopter. The 3D trajectory tracking results show that the overall trajectory remains highly consistent with the commanded path, and the aircraft can accurately follow the preset complex trajectory, including maneuvers such as horizontal turns and altitude changes. The system exhibits good trajectory tracking robustness and dynamic response capabilities.

[0095] Figure 6 Figure (b) is a projection view of the unmanned helicopter's flight trajectory on the horizontal plane (XY plane). Figure 6 Figure (c) shows the response curve of the unmanned helicopter's flight trajectory in the vertical direction (altitude-time).

[0096] When applying the unmanned helicopter trajectory tracking method based on active disturbance rejection and explicit model tracking provided in this manual, it is not necessary to consider... Figure 2 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this manual does not impose any restrictions on it.

[0097] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0098] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A trajectory tracking method for an unmanned helicopter, characterized in that, The method includes: At any moment during unmanned helicopter trajectory tracking, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter, a three-axis speed control command for the unmanned helicopter is generated; the three-axis speed control command includes the desired longitudinal speed, the desired lateral speed, and the desired vertical speed. The three-axis speed control command is processed to obtain the desired attitude angle command; the desired attitude angle command includes the desired pitch angle command, the desired roll angle command, and the desired vertical speed command. In the explicit model controller, the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, the desired roll angle command, the desired vertical speed command, and the yaw rate command are obtained respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and then added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical speed. The actuators of the unmanned helicopter are driven by the control of pitch, roll, heading, and lift to achieve trajectory tracking.

2. The trajectory tracking method for an unmanned helicopter as described in claim 1, characterized in that, The acquisition of the feedforward control quantity, total internal and external disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, desired roll angle command, desired vertical velocity command, and yaw rate command, respectively, specifically includes: For any one of the desired attitude angle commands, including the desired pitch angle command, the desired roll angle command, the desired vertical velocity command, and the yaw rate command, the desired attitude angle command is input into the preset explicit model for calculation to obtain the ideal reference state. The actual flight status of unmanned helicopters is obtained based on helicopter flight dynamics models; The actual flight state of the unmanned helicopter is compared with the ideal reference state output by the explicit model to obtain the state tracking error of the system. By using forward gain, forward gain diagonal matrix, decoupling matrix, and control matrix, the state tracking error signal is proportionally gained, integrated, and superimposed to obtain the feedforward control quantity corresponding to the desired attitude angle command; The ideal reference state is smoothed and differentiated using LTD to obtain smoothed position and smoothed speed commands. The actual flight state and the control input from the previous moment are input into the Linear Extended State Observer (LESO) to estimate the system state and observe the total internal and external disturbance compensation in real time. Calculate the error between the smooth position command and the smooth speed command and the estimated state obtained by LESO, and input the error into the linear state error feedback control law LSEF to obtain the feedback compensation amount.

3. The trajectory tracking method for an unmanned helicopter as described in claim 2, characterized in that, The process of performing proportional gain, integration, and superposition on the state tracking error signal using the forward gain, forward gain diagonal matrix, decoupling matrix, and control matrix to obtain the feedforward control quantity corresponding to the desired attitude angle command specifically includes: The rate signal is obtained by proportionally increasing the forward gain of the state tracking error signal; The difference between the rate signal and the actual rate signal is defined as the rate error; The rate error is processed by proportional gain processing using a forward gain diagonal matrix and a decoupling matrix to obtain a first signal. The first signal is integrated through a control matrix that includes an integral function to obtain the second signal; The first signal and the second signal are superimposed to obtain the feedforward control quantity corresponding to the desired attitude angle command.

4. The trajectory tracking method for an unmanned helicopter as described in claim 2, characterized in that, The formula for calculating the control vector is: ； in, The control vector at the current moment, , To control pitch, To control the roll, To control lift, To control the course, This is the feedforward control variable for the explicit model. To provide feedback on compensation amount, This represents the total compensation amount for internal and external disturbances. To control the gain; The formula for calculating the feedback compensation amount is: ； in, Angle estimates calculated for LESO. and Both represent the tracking error between the ideal trajectory of the explicit model and the system state estimated by LESO. , , Angular velocity estimates calculated for LESO For error feedback control, the proportional gain The differential gain for error feedback control; The feedforward control quantity The calculation formula is: ； in, This is the feedforward control variable. and All are explicit model control matrices. e This refers to the rate error in the explicit model control loop.

5. The trajectory tracking method for an unmanned helicopter as described in claim 2, characterized in that, The formula corresponding to the helicopter flight dynamics model is: ； in, The forward flight speed of the unmanned helicopter. The lateral velocity of the unmanned helicopter. The vertical velocity of the unmanned helicopter. For unmanned helicopters to circle x Angular velocity of the shaft rotation, Unmanned helicopters circle y Angular velocity of the shaft rotation, For unmanned helicopters to circle z Angular velocity of the shaft rotation, Circling the fuselage of the unmanned helicopter x Moment of inertia of the shaft Circling the fuselage of the unmanned helicopter y Moment of inertia of the shaft Circling the fuselage of the unmanned helicopter z Moment of inertia of the shaft The pitch angle of the unmanned helicopter around its body axis. The roll angle of the unmanned helicopter around its body axis. This is the yaw angle of the unmanned helicopter around its body axis. Forward acceleration of the body, This refers to the lateral acceleration of the aircraft. The vertical acceleration of the body. For roll acceleration, For pitch acceleration, Yaw acceleration, This represents the rate of change of the roll angle. The rate of change of pitch angle, The rate of change of yaw angle. The force generated by the main rotor on the airframe x Components on the axis, The force generated by the fuselage in the fuselage x Components on the axis, The force generated by the main rotor on the airframe y Components on the axis, The force generated by the fuselage in the fuselage y Components on the axis, The force generated by the tail rotor on the fuselage y Components on the axis, The force generated by the main rotor on the airframe z Components on the axis, The force generated by the fuselage in the fuselage z Components on the axis, The rolling torque generated by the main rotor The rolling torque generated by the tail rotor It is the acceleration due to gravity. The anti-torsional torque of the main rotor, The yaw moment generated by the tail rotor m The mass of the unmanned helicopter.

6. The trajectory tracking method for an unmanned helicopter as described in claim 2, characterized in that, When the object processed in the attitude loop is a pitch angle command, an ideal reference model that meets the flight quality specifications is set; the ideal reference model is constructed in the form of an explicit model; the formula corresponding to the explicit model is: ； in, For the desired pitch angle state, For natural frequency, Input commands for the vertical channel. The damping ratio; When the object processed in the attitude loop is a pitch angle command, the dynamic equation of the pitch channel is: ； in, The rate of change of pitch acceleration, The total disturbance experienced by the system For the control signals output to the helicopter, To control the gain; When the object processed in the attitude loop is a pitch angle command, the corresponding calculation formula for the Linear Extended State Observer (LESO) is: ； in, To show the tracking error between the ideal pitch angle of the model and the LESO angle estimate, The rate of change of the estimated angle for LESO was calculated. The rate of change of the estimated angular velocity calculated for LESO. The LESO estimate of the rate of change of total disturbance to the pitch channel. To correct the angle estimation error for the observer gain, To correct the angular velocity estimation error for the observer gain, The observer gain is used to correct the total disturbance estimation error; When the object processed in the attitude loop is a pitch angle command, the generated control quantity is: ； in, For controlling the pitch at the current moment, This is the feedforward control quantity for the explicit model. For the ideal pitch angle, The ideal pitch angular velocity.

7. The trajectory tracking method for an unmanned helicopter as described in claim 1, characterized in that, The process of generating three-axis velocity control commands for the unmanned helicopter based on its desired trajectory in the ground coordinate system and its actual position includes: Obtain the desired ideal trajectory and the actual position of the unmanned helicopter in the ground coordinate system; the desired ideal trajectory is a three-dimensional coordinate vector. The desired trajectory of the unmanned helicopter and its actual position are compared. x Input the direction difference to x The desired lateral velocity is obtained using the directional linear active disturbance rejection controller XLADRC. The desired trajectory of the unmanned helicopter and its actual position are compared. y Input the direction difference to y The desired longitudinal velocity is obtained using the YLADRC (Directional Linear Active Disturbance Rejection Controller). The desired trajectory of the unmanned helicopter and its actual position are compared. z Input the direction difference to z The desired vertical velocity is obtained using the directional linear active disturbance rejection controller ZLADRC. The desired lateral velocity, the desired longitudinal velocity, and the desired vertical velocity are determined as three-axis velocity control commands.

8. The trajectory tracking method for an unmanned helicopter as described in claim 1, characterized in that, The process of performing speed control processing on the three-axis speed control command to obtain the desired attitude angle command specifically includes: Obtain three-axis speed control commands for the unmanned helicopter; the three-axis speed control commands include desired lateral speed, desired longitudinal speed, and desired vertical speed; Obtain the actual speed of the unmanned helicopter; the actual speed includes the actual longitudinal speed, the actual lateral speed, and the actual vertical speed. The difference between the desired lateral velocity and the actual lateral velocity is used to obtain the lateral velocity tracking error. The difference between the desired longitudinal speed and the actual longitudinal speed is used to obtain the longitudinal speed tracking error. The difference between the desired longitudinal velocity and the actual longitudinal velocity is used to obtain the vertical velocity tracking error. The longitudinal velocity tracking error, the lateral velocity tracking error, and the vertical velocity tracking error are respectively input to the speed controller to generate the desired pitch angle, desired roll angle, and desired vertical velocity; The desired pitch angle, the desired roll angle, and the desired vertical velocity are determined as the desired attitude angle command for the unmanned helicopter.

9. The trajectory tracking method for an unmanned helicopter as described in claim 1, characterized in that, The formula for calculating the yaw rate command is: ； in, The yaw rate command. This is the initial forward velocity of the helicopter when it is in a horizontal forward flight state. The lateral speed generated during heading coordination control. This represents the current flight speed of the unmanned helicopter.

10. A trajectory tracking system for an unmanned helicopter, characterized in that, Includes attitude loop, velocity loop, and position loop; The position loop is used to generate three-axis speed control commands for the unmanned helicopter at any moment during trajectory tracking, based on the desired ideal trajectory of the unmanned helicopter in the ground coordinate system and the actual position of the unmanned helicopter; the three-axis speed control commands include desired longitudinal speed, desired lateral speed and desired vertical speed. The speed loop is used to process the three-axis speed control commands to obtain the desired attitude angle commands; the desired attitude angle commands include the desired pitch angle command, the desired roll angle command, and the desired vertical speed command. The attitude loop is used in the explicit model controller to obtain the feedforward control quantity, internal and external total disturbance compensation quantity, and feedback compensation quantity corresponding to the desired pitch angle command, the desired roll angle command, the desired vertical velocity command, and the yaw rate command, respectively. The feedback compensation quantity is subtracted from the internal and external total disturbance compensation quantity to obtain the corresponding disturbance rejection compensation quantity. The disturbance rejection compensation quantity is divided by the control gain and added to the feedforward control quantity to obtain the corresponding control vector. The control vector includes the control pitch corresponding to the pitch angle, the control roll corresponding to the roll angle, the control heading corresponding to the yaw rate, and the control lift corresponding to the vertical velocity.

Images