A self-disturbance rejection control method for a multi-rotor aerial robot for tree obstacle clearing operations

Abstract

The present invention discloses a method for self-disturbance rejection control of a multi-rotor aerial robot for tree obstacle clearing operations, and the method comprises the following steps: (1) designing the structure of a new type of aerial robot according to the requirements of the aerial robot for the power transmission line operation process, including adding a set of ducted thrusters to the belly of the aerial robot; (2) establishing a mathematical model of the new type of aerial robot according to the structure in step (1), including a kinematic model and a dynamic model; (3) designing a self-disturbance rejection flight control law according to the model established in step (2). The present invention realizes a self-disturbance rejection attitude control of a non-planar multi-rotor aerial robot that can realize forward and backward translational motion without attitude coordination, which can overcome the shortcomings of attitude coordination position movement of traditional planar multi-rotor drones, so that the new structure robot has good stability, translation and anti-disturbance, and finally improves the operation efficiency of aerial operations of power transmission lines.

Description

Technical Field

[0001] The invention relates to the field of aviation aircraft and robot technology, and in particular to a self-disturbance control method for a multi-rotor aerial robot for tree obstacle clearing operation. Background Art

[0002] Trees near high-voltage transmission line channels often exceed the safe distance, causing the lines to discharge through the trees to the ground, resulting in power outages, fires and other safety accidents, which brings great inconvenience to social production and life. Therefore, the power sector spends a lot of manpower and material resources on tree barrier clearing every year. At present, the main method is mostly manpower, supplemented by simple tools such as hand saws. This cleaning method is not only limited in efficiency, but also cannot guarantee human safety. In my country, casualties caused by such tasks occur from time to time. Therefore, it is particularly necessary to develop and promote a set of efficient and safe tree barrier clearing aerial robots that can replace manual cleaning methods.

[0003] Multi-rotor aerial robots that can take off and land vertically and hover in the air have the advantages of simple structure and good stability, and their application research as working platforms has received widespread attention. The rotors of common multi-rotor aircraft are generally configured in a plane, that is, the rotors are fixed on the same plane. However, the thrust generated by them always points in the same direction, resulting in deep coupling of the aircraft position and attitude dynamics equations, that is, the underactuation phenomenon. This requires the aircraft to complete movement through large-angle attitude coordination, which is also an important factor restricting the current application of traditional structural rotorcraft to achieve contact operations. Because in the process of aerial robots performing aerial operations, they need to translate forward and backward, and keep the body attitude stable to maintain the attitude stability of the working tool, which is impossible to achieve on traditional plane-configured rotor configuration aerial robots. In the task of clearing tree obstacles, this will easily cause the working tool to get stuck on the tree obstacle. Therefore, it is necessary to adopt a new configuration to overcome the physical defects in the traditional configuration. When the aerial robot is used as an operating platform, the disadvantage of underactuation of the traditional aircraft with plane-configured rotors reduces the translation of the platform. In addition, since redirecting the thrust direction of the rotor that is fixed to the fuselage requires attitude coordination, there is a time delay that reduces the platform's anti-interference ability.

[0004] The document "Dario B, D'Andrea R. An omni-directional multirotor vehicle [J]. Mechatronics, 2018, 55: 76-93 (Dario B, D'Andrea R. An omni-directional multirotor vehicle, Mechatronics Systems, 2018, 55: 76-93)" conducts static force and torque analysis on multirotor aircraft with non-planar rotor configuration, transforms the design of such aircraft into an optimization problem, designs an eight-rotor omnidirectional and fully-drive aircraft, and then designs its position and attitude tracking control law based on loop shaping and feedback linearization methods.

[0005] The paper "Tadokoro Y, Ibuki T, Sampei M. Manipulability Analysis of a Fully-Actuated Hexrotor UAV Considering Tilt Angles and Arrangement of Rotors[C]. World Congress of the International Federation of Automatic Control, 2017." analyzes the dynamics of the hexrotor and shows that the distribution position of the rotors will not affect the force and counter-torque of each rotor acting on the center of mass of the fuselage. It also redefines the dynamic maneuverability index to describe the maneuverability of the fully-driven hexrotor aircraft. Finally, with the goal of improving the index, the rotor distribution position and tilt angle are optimized, and a hexrotor aircraft configuration with omnidirectional mobility is designed.

[0006] The paper "Jiang G, Voyles R, Sebesta K. Estimation and optimization of fully-actuated multirotor platform with nonparallel actuation mechanism [C]. IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS), 2017. (Jiang G, Voyles R, Sebesta K. Estimation and optimization of fully-actuated multirotor platform with nonparallel actuation mechanism, IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS), 2017.)" studied a mathematical model of a fully-driven six-rotor UAV platform with a non-parallel rotor configuration, tested its response time to horizontal wind disturbance and the rise time of horizontal thrust, and compared it with the under-actuated six-rotor UAV with a standard planar rotor configuration to illustrate the effectiveness of the model. As can be seen from the above, a fully-driven multi-rotor aircraft with a non-planar configuration also has good maneuverability through proper design, but this type of aircraft has a low energy efficiency due to the large internal interaction between the rotors, and the research focus is more on improving the maneuverability or certain indicators of the aircraft.

[0007] In addition to high requirements for the platform's maneuverability, the large inertia of the pitch and yaw channels caused by the working tools loaded on the platform also requires the platform to have strong anti-disturbance capabilities. In addition to vectoring the platform's thrust, the use of flight control strategies with higher anti-disturbance efficiency has also received attention. Control methods or technologies such as sliding mode control, RISE (signum of error) and active disturbance rejection can better suppress interference from the operating environment or the platform. Among them, the active disturbance rejection control method can effectively estimate and suppress external disturbances and is easy to implement in engineering. There is no report on the use of active disturbance rejection control methods for non-planar rotor aerial robots. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a self-disturbance rejection control method for a multi-rotor aerial robot for tree obstacle clearing operations, so as to solve the technical problems existing in the prior art.

[0009] The technical solution adopted by the present invention is: a method for self-disturbance rejection control of a multi-rotor aerial robot for tree obstacle clearing operation, the method comprising the following steps:

[0010] Step 1: According to the requirements of the aerial robot for the power transmission line operation process, the structure of the new type of aerial robot is designed, including adding a set of ducted thrusters to the belly of the aerial robot;

[0011] Step 2, based on the structure designed in step 1, a mathematical model of the new operational aerial robot is established, the mathematical model including a kinematic model and a dynamic model;

[0012] Step 3: Design the anti-disturbance flight control law based on the mathematical model established in step 2.

[0013] The requirements for the operation process in step 1 are: 1) the aerial robot platform has a stable posture; 2) it can provide the operation direction, i.e., the body axis x b Direction of thrust.

[0014] The dynamic model in step 2 analyzes the forces and torques generated by the X-mode quadrotor and the forces and torques generated by the thrusters. On this basis, the dynamic model of the position and attitude of the aircraft is obtained according to Newton-Euler's laws of motion.

[0015] Among them, the forces and moments generated by the X-mode quadrotor are as follows:

[0016] f i =k rf n i 2 , i=1,2,3,4

[0017]

[0018] In the formula, f r is the resultant force generated by the quadrotor, f 1 to f 4 is the thrust generated by each rotor of the quadrotor, k rf is the rotor lift coefficient; n i is the rotation speed of each of the four rotors;

[0019]

[0020] Where M r is the three-axis torque caused by the quadrotor, l r is the distance between each rotor and the center of mass at x b or b The projection length of the axis, k rm is the anti-torque coefficient of each rotor;

[0021] The forces and torques generated by the thrusters are as follows:

[0022] f 5 =k tf n 5 2 ,f 6 =k tf n 6 2

[0023] In the formula, f 5 and f 6 is the thrust generated by the two thrusters, k tf is the thrust coefficient of the propeller;

[0024]

[0025] Where M t is the three-axis torque generated by the thruster, l ty and l tz The distance between the center of mass of the two symmetrically distributed thrusters and the center of mass of the aircraft is in y b and z b Projection length on the axis, k tm is the anti-torque coefficient of the thruster, n 6 and n 5 Indicates the propeller motor speed.

[0026] The dynamic model of the aerial robot's position and posture is as follows:

[0027]

[0028] In the formula, m is the mass of the machine body, is the body position, g is the gravitational acceleration, I b is a 3rd order diagonal matrix diga(I x ,I y ,I z ), ω is the component of the body speed under the body axis (p, q, r), the diagonal elements represent the moment of inertia of the platform around the three body axes, R is O E x E y E z E With O b x b y b z b The transformation matrix is ​​expressed as follows:

[0029]

[0030] Where C stands for cosine and S stands for sin.

[0031] The aerial robot's self-disturbance rejection attitude control law in step 3 adopts an inner and outer loop strategy, where the outer loop is a position closed-loop tracking control and the inner loop is an attitude closed-loop tracking control. The design steps of the aerial robot's self-disturbance rejection attitude control law are as follows:

[0032] 1) Position tracking control law is based on the actual position value (x, y, z) and the expected position value Calculate the control amount Represents the virtual forces along the three axes of the world coordinate system;

[0033] 2) The allowed pitch angle variation range is 0 by default. When the aerial robot is not in operation, it is changed to non-zero. Therefore, the desired pitch angle θ d is 0, the expected yaw angle ψ d It is set manually to 0. Based on this, according to the dynamic equation Transformed into (U 5 ,U 1 ,φ d ), U 5 is the expected combined force generated by the two horizontal thrusters, U 1 is the expected resultant force of the quadrotor system, φ d represents the desired roll angle;

[0034] 3) The attitude tracking control law is based on the actual attitude (φ, θ, ψ) and the expected attitude (φ d ,θ d ,ψ d ) generates the control quantity (U 2 ,U 3 ,U 4 ), respectively represent the virtual control torque around the three coordinate axes in the body coordinate system;

[0035] 4) In order to minimize the impact of horizontal thrust on the platform attitude, let n 5 and n 6 equal, and the moment M caused by the horizontal thrust t It is considered as a disturbance in the attitude control law and estimated by the extended state observer, and compensated in the control law;

[0036] 5) will (U 1 ,U 2 ,U 3 ,U 4 ) is converted into but:

[0037]

[0038] Will U 5 According to the following conversion

[0039]

[0040] Beneficial effects of the present invention: Compared with the prior art, the effects of the present invention are as follows:

[0041] 1) In order to overcome the shortcomings of the traditional planar multi-rotor drone in attitude coordination position movement, the method of the present invention proposes and designs a non-planar operation type multi-rotor aerial robot that can achieve forward and backward translational movement without attitude coordination on the basis of a full-drive multi-rotor aircraft, which has good stability, maneuverability and anti-interference;

[0042] 2) The method of the present invention not only enables the aerial robot to achieve forward and backward translational motion without changing its pitch posture on the basis of hovering, but also plays a good role in suppressing unknown external disturbances to the robot during operation;

[0043] 3) The method of the present invention fully considers the factors that the non-planar multi-rotor aerial robot has large internal forces, rotational inertia, and interference from tree obstacle contact forces. On this basis, the proposed anti-disturbance flight control law ensures the stability of the posture of the aerial robot for high-voltage transmission line operations in normal flight and cutting operations;

[0044] 4) The anti-disturbance flight control law proposed in the present invention can effectively suppress the interference from the operating environment or the inside of the platform, and its control parameters are easy to adjust, which is suitable for engineering implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the robot model designed by the present invention.

[0046] Figure 2 This is a schematic diagram of the implementation principle of the present invention.

[0047] Figure 3 Structural diagram of posture tracking control law

[0048] Figure 4 This is the structure diagram of the robot position x self-disturbance rejection tracking control law of the present invention.

[0049] Figure 5 This is the step response diagram of the robot posture system of the present invention.

[0050] Figure 6 This is the step response diagram of the robot position system of the present invention.

[0051] Figure 7 This is a step response diagram of the attitude system of the robot of the present invention in the forward flight state.

[0052] Figure 8 It is a curve diagram of the ESO state changes of the robot position z of the present invention.

[0053] Fig. 9 This is a graph of the robot path tracking of the present invention. DETAILED DESCRIPTION

[0054] The present invention is further described below in conjunction with specific embodiments.

[0055] Example 1: Figure 1-9 As shown, a method for anti-disturbance control of a multi-rotor aerial robot for tree obstacle clearing operation comprises the following steps:

[0056] Step 1: According to the requirements of the aerial robot for high-voltage transmission line operation, the structure of the new aerial robot is designed, including adding a set of ducted thrusters to the belly of the aerial robot;

[0057] Step 2, based on the structure designed in step 1, derive a mathematical model of the new operational aerial robot, including a kinematic model and a dynamic model;

[0058] Step 3: Based on the mathematical model established in step 2, design the anti-disturbance flight control law, such as Figure 3 shown.

[0059] Among them, in step 1, the configuration design of the working multi-rotor aerial robot is as follows: Figure 1 Structure shown: When the aerial robot is working on high-voltage transmission lines, it needs to carry an operating robot arm, which is located in the middle of the belly of the robot, where the body axis is located. The operating process requires: 1) The aerial robot platform has a stable posture; 2) It can provide the operating direction, that is, the body axis x b Ordinary quadrotors require posture coordination to generate thrust in a specified direction. In order to solve this contradiction, the present invention adds a set of ducted thrusters to the belly of the aerial robot.

[0060] The shape of the work platform, the thrust of each propeller and the direction of rotor rotation, the body coordinate system O b x b y b z b , world coordinate system O E x E y E z E , the schematic diagram of the robot arm and the counterweight (battery) is as follows Figure 1 As shown, O b Located at the body's center of mass.

[0061] In step 2, the mathematical model of the new operational aerial robot is established:

[0062] The forces and torques generated by the X-mode quadrotor and the forces and torques generated by the thrusters are analyzed, and on this basis, the dynamic model of the position and attitude of the aircraft is obtained according to Newton-Euler's laws of motion.

[0063] The forces and moments generated by the X-mode quadrotor are as follows:

[0064] f i =k rf n i 2 ,i=1,2,3,4

[0065]

[0066] In the formula, f r is the resultant force generated by the quadrotor, f 1 to f 4 is the thrust generated by each rotor of the quadrotor, k rf is the rotor lift coefficient; n i is the rotation speed of each rotor;

[0067]

[0068] Where M r is the three-axis torque caused by the quadrotor, l r is the distance between each rotor and the center of mass at x b or b The projection length of the axis, k rm is the anti-torque coefficient of each rotor;

[0069] The forces and moments generated by the thrusters are as follows:

[0070] f 5 =k tf n 5 2 ,f 6 =k tf n 6 2

[0071] In the formula, f 5 and f 6 is the thrust generated by the two thrusters, k tf is the thrust coefficient of the propeller;

[0072]

[0073] Where M t is the three-axis torque generated by the thruster, l ty and l tz The distance between the center of mass of the two symmetrically distributed thrusters and the center of mass of the aircraft is in y b and z b Projection length on the axis, k tm is the anti-torque coefficient of the thruster, n 6 and n 5 Indicates the propeller motor speed.

[0074] The dynamic model of the aerial robot's position and posture in step 2 is as follows:

[0075]

[0076] In the formula, m is the mass of the machine body, is the body position, g is the gravitational acceleration, I b is a 3rd order diagonal matrix diga(I x ,I y ,I z ), ω is the component of the body speed under the body axis (p, q, r), the diagonal elements represent the moment of inertia of the platform around the three body axes, R is O E x E y E z E With O b x b y b z b The transformation matrix is ​​expressed as follows, where, to simplify writing, C represents cosine and S represents sin.

[0077]

[0078] In step 3, the ADRC flight control law is designed:

[0079] Take the position active disturbance rejection control law as an example:

[0080] The description form of the aerial robot position motion model is a multi-input multi-output (MIMO) system. In order to apply the ADRC suitable for the single-input single-output (SISO) system to the design of the position tracking control law of the aerial robot, the description form of the system equation is firstly introduced into the virtual control quantity The method is transformed into one expressed by a combination of multiple SISO equations.

[0081]

[0082] Since θ d is 0, ψ d It is known that with (U 5 ,U 1 ,φ d ) has the following relationship:

[0083]

[0084] The following takes position x as an example:

[0085] Rewrite the system equation as follows, where d x is the total possible internal and external disturbance, u x represent

[0086]

[0087] The discrete ESO is designed as follows:

[0088]

[0089] Where T is the sampling period of the discrete system, (α 1 , α 2 , δ, β 01 , β 02 , β 03 , b x ) is an adjustable parameter, z 3 represent Where fal has the following expression:

[0090]

[0091] According to the literature “Guo B, Zhao Z. On convergence of nonlinear active disturbance rejection for SISO systems [C]. IEEE Conference on Control and Decision, 2012: 434-441. (Guo B, Zhao Z. Convergence of nonlinear active disturbance rejection control for SISO systems, IEEE Control and Decision Conference, 2012: 434-441)” and the literature “Guo B, Zhao Z. On convergence of the nonlinear active disturbance rejection control for MIMO systems [J]. SIAM Journal on Control and Optimization, 2013, 51 (2): 1727-1757. (Convergence of nonlinear active disturbance rejection control for MIMO systems, SIAM Control and Optimization Journal, 2013, 51 (2): 1727-1757.)”, the stability and convergence of the observer have been proved.

[0092] After that, a tracking differentiator (TD) is used to design the transition process for the reference input signal. The second-order TD expression is as follows:

[0093]

[0094] Where v 1 Tracking reference input x d ,(v 2 ,f h )) are the transition process v 1 The first and second order derivatives of , (r,h) are adjustable parameters.

[0095]

[0096] Finally, the following state error feedback (SEF) law is adopted, and c, the damping factor, also needs to be adjusted.

[0097]

[0098] The structure of the channel control law is as follows: Figure 4 shown.

[0099] Application examples of the present invention are described below.

[0100] A series of simulation experiments of the aerial robot will be designed below, including: step response of the posture system, motion of position x, test of the ESO estimation system state and disturbance in the self-disturbance rejection control law, and trajectory tracking experiment under disturbance conditions. The specific parameters of the mathematical model of the aerial robot for high-voltage transmission line operation are as follows:

[0101] symbol Numeric unit <![CDATA[k rf ]]> <![CDATA[3.11×10 -7 ]]> <![CDATA[N / rad 2 ]]> <![CDATA[l r ]]> 0.47 m <![CDATA[k rm ]]> <![CDATA[5.63×10 -9 ]]> <![CDATA[N·m / rad 2 ]]> <![CDATA[k tf ]]> <![CDATA[4.15×10 -7 ]]> <![CDATA[N / rad 2 ]]> <![CDATA[k tm ]]> <![CDATA[4.167×10 -10 ]]> <![CDATA[N·m / rad 2 ]]> <![CDATA[l tx ,L ty ,L tz ]]> 0,0.1,0.02 m <![CDATA[I x ,I y ,I z ]]> 3.02,3.69,0.72 <![CDATA[kg·m 2 ]]> m 11.85 kg g 9.8 N / kg

[0102] During the simulation, the TD parameter r is 40000, h is the system time T, which is 0.001; the ESO parameter (α 1 , α 2 , δ, β 01 , β 02 ) is (0.5, 0.25, 0.01, 1000, 19764), β of ESO of attitude (φ, θ, ψ) and position (x, y, z) channels 03 The values ​​are (116280, 116280, 88207, 462920, 58278, 462920) respectively; the remaining parameters are as shown in the following table.

[0103] project φ θ ψ x y z ESO-b 0.33 0.27 1.38 0.08 0.08 0.08 SEF-h 0.01 0.01 0.01 0.01 0.1 0.01 SEF-c 2.5 2.5 2.5 3.5 3 3.5 SEF-r 12 12 12 35 8 72

[0104] Figure 5 It can be seen that the control systems of the three channels of attitude have good performance.

[0105] Figure 6 The three position coordinate variables track the corresponding step response signals well, which illustrates the effectiveness of the designed position control law.

[0106] Figure 7 The figure shows the change of position and attitude angle when position x moves forward. It can be seen from the upper and lower figures that position x can complete the forward translation movement and stop accurately without the coordination of attitude angle θ, which verifies the effectiveness of the flight platform designed by the present invention and meets the engineering needs. Among them, when position x changes, the slight fluctuation of θ is due to the M caused by the horizontal thrust. t It takes some time for ESO to detect and compensate.

[0107] Figure 8 For the presence of disturbance d z =50+50sin2t+150u(t-2), the ESO of position z in the anti-disturbance control law affects position z and speed v respectively. z and the observed values ​​of the disturbance. It can be seen from the figure that the designed ADRC control law can well estimate and suppress the external disturbance force, and can also better track the position and its differential.

[0108] Fig. 9 The disturbance d is shown z =5+5sin2t+5u(t-2) and d z =50+50sin2t+150u(t-2) is a schematic diagram of the three-dimensional flight trajectory of the flight platform tracking a given path. For ease of observation, the sign of the position z is reversed, that is, from negative to positive. It can be seen that even in the presence of disturbances, the platform can still track the target path well, indicating that the designed flight platform and its control law have good performance.

[0109] Experiments show that the present invention overcomes the shortcomings of the traditional planar multi-rotor drone's attitude-coordinated position movement, and designs a non-planar working multi-rotor aerial robot that can achieve forward and backward translational motion without attitude coordination, which has good stability, maneuverability and anti-interference. The present invention not only enables the aerial robot to achieve forward and backward translational motion on the basis of hovering without attitude pitch changes, but also has a good inhibitory effect on unknown external disturbances to the body during operation. The present invention fully considers factors such as the large internal force, moment of inertia and interference from tree obstacle contact force of the non-planar multi-rotor aerial robot. On this basis, the self-interference flight control law proposed ensures the stability of the attitude of the high-voltage power transmission aerial robot in normal flight and cutting operation states. The self-interference flight control law proposed in the present invention can better suppress interference from the working environment or the inside of the platform, and its control parameters are easy to adjust, which is suitable for engineering implementation.

[0110] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for anti-disturbance control of a multi-rotor aerial robot for tree obstacle clearing operations. Features: The method comprises the following steps: Step 1: According to the requirements of the aerial robot for the power transmission line operation process, the structure of the new type of aerial robot is designed, including adding a set of ducted thrusters to the belly of the aerial robot; Step 2, based on the structure designed in step 1, a mathematical model of the new operational aerial robot is established, the mathematical model including a kinematic model and a dynamic model; Step 3, designing an anti-disturbance flight control system based on the mathematical model established in step 2; The dynamic model in step 2 is to analyze the forces and torques generated by the X-mode quadrotor and the forces and torques generated by the thrusters, and on this basis, the dynamic model of the position and attitude of the aircraft is obtained according to Newton-Euler's laws of motion; The forces and moments generated by the X-mode quadrotor are as follows: f i =k rf n i 2 ,i=1,2,3,4 In the formula, f r is the resultant force generated by the quadrotor, f 1 to f 4 is the thrust generated by each rotor of the quadrotor, k rf is the rotor lift coefficient; n i is the rotation speed of each of the four rotors; Where M r is the three-axis torque caused by the quadrotor, l r is the distance between each rotor and the center of mass at x b or b The projection length of the axis, k rm is the anti-torque coefficient of each rotor; The forces and torques generated by the thrusters are as follows: f 5 =k tf n 5 2 ,f 6 =k tf n 6 2 In the formula, f 5 and f 6 is the thrust generated by the two thrusters, k tf is the thrust coefficient of the propeller; Where M t is the three-axis torque generated by the thruster, l ty and l tz The distance between the center of mass of the two symmetrically distributed thrusters and the center of mass of the aircraft is in y b and z b Projection length on the axis, k tm is the anti-torque coefficient of the thruster, n 6 and n 5 Respectively represent the motor speeds of the two thrusters; The dynamic model of the aerial robot's position and posture is as follows: In the formula, m is the mass of the machine body, is the body position, g is the gravitational acceleration, I b is a 3rd order diagonal matrix diga(I x ,I y ,I z ), ω is the component of the body speed under the body axis (p, q, r), the diagonal elements represent the moment of inertia of the platform around the three body axes, and R is the world coordinate system O E x E y E z E With the body coordinate system O b x b y b z b The transformation matrix is ​​expressed as follows: In the formula, C represents cosine and S represents sin; The aerial robot's anti-disturbance attitude control law adopts an inner-outer loop strategy, where the outer loop is a position closed-loop tracking control and the inner loop is an attitude closed-loop tracking control. The design steps of the aerial robot's anti-disturbance attitude control law are as follows: 1) Position tracking control law is based on the actual position value (x, y, z) and the expected position value (x d ,y d ,z d ) Calculate the control quantity Represents the virtual forces along the three axes of the world coordinate system; 2) The allowed pitch angle variation range is 0 by default. When the aerial robot is not in operation, it is changed to non-zero. Therefore, the desired pitch angle θ d is 0, the expected yaw angle ψ d It is set manually to 0. Based on this, according to the dynamic equation Transformed into (U 5 ,U 1 ,φ d ), U 5 is the expected combined force generated by the two horizontal thrusters, U 1 is the expected resultant force of the quadrotor system, φ d represents the desired roll angle; 3) The attitude tracking control law is based on the actual attitude (φ, θ, ψ) and the expected attitude (φ d ,θ d ,ψ d ) generates the control quantity (U 2 ,U 3 ,U 4 ), respectively represent the virtual control torque around the three coordinate axes in the body coordinate system; 4) To minimize the impact of the horizontal thrust on the platform attitude, let n 5 and n 6 be equal, and the moment M t caused by the horizontal thrust is regarded as a disturbance in the attitude control law and estimated by the extended state observer, and compensated in the control law; 5) Convert (U 1 , U 2 , U 3 , U 4 ) according to the following formula into Then: Will U 5 Convert to 2. According to the method for anti-disturbance control of a multi-rotor aerial robot for tree obstacle clearing operation in claim 1, Features: The requirements for the operation process in step 1 are: 1) the aerial robot platform has a stable posture; 2) it can provide the operation direction, i.e., the body axis x b Direction of thrust.

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