Mountain oil and gas pipeline inspection unmanned aerial vehicle flight control method and system

Abstract

This disclosure provides a method and system for flight control of a drone used for inspecting oil and gas pipelines in mountainous areas. Relating to the field of flight control, this invention employs a dynamic inverse control law to linearize and decouple the system compared to traditional PID controllers (Proportional-Integral-Derivative controllers), achieving excellent control performance for high angle-of-attack maneuvers of fixed-wing drones. Furthermore, the introduction of a disturbance observer effectively estimates the total disturbance caused by wind disturbance and model uncertainties, compensating for it in the dynamic inverse controller and improving system robustness. Considering the nonlinear characteristics of the system, it effectively addresses the problem that commonly used linear control algorithms cannot meet the requirements for flight robustness. This invention is used for inspecting oil and gas pipelines in mountainous areas.

Description

A method and system for flight control of unmanned aerial vehicles (UAVs) for inspecting oil and gas pipelines in mountainous areas Technical Field

[0001] This invention relates to the field of flight control, and in particular to a method and system for flight control of a drone used for inspecting oil and gas pipelines in mountainous areas. Background Technology

[0002] Currently, drone inspection, as an emerging inspection method, has begun to show its potential in oil and gas pipeline inspection. In particular, vertical take-off and landing drones, unlike fixed-wing drones, do not require runways or recovery devices, have long endurance, and perform especially well in the inspection of long-distance pipelines. By carrying various equipment (high-definition cameras, dual-light pods, laser methane telemetry instruments, etc.), they can promptly capture the environmental conditions around the pipeline and report them to management personnel for processing.

[0003] Currently, oil and gas pipelines in mountainous areas face significant terrain variations and frequent geological disasters, making manual inspections often difficult. Furthermore, the presence of turbulent waters in mountainous terrain poses challenges to drone inspections and can even threaten flight safety. Commonly used linear control algorithms cannot meet the requirements for flight robustness. Summary of the Invention

[0004] According to a first aspect of the present invention, a method for flight control of a mountainous oil and gas pipeline inspection drone is provided, which can solve the problem that commonly used linear control algorithms cannot meet the requirements of flight robustness.

[0005] This invention provides a method for flight control of a drone used for inspecting oil and gas pipelines in mountainous areas. The method includes the following steps:

[0006] Step 1: Establish a mathematical model for attitude control of a vertical take-off and landing fixed-wing UAV in cruise mode; set the desired attitude angle, and obtain the UAV attitude angle vector and angular velocity vector as inputs to the attitude angle controller;

[0007] Step 2 involves designing the UAV attitude angle loop control based on a dynamic inverse controller to obtain the expected value X of the attitude angular velocity. 2c ;

[0008] Step 3 is based on the expected value X of the attitude angular velocity. 2c The design of the UAV angular velocity loop controller, which incorporates a dynamic inverse controller and an interference observer, enables flight control of the UAV.

[0009] Preferably, the mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV established in step 1 is as follows:

[0010]

[0011] Wherein, the state variables X1 = [φ, θ, ψ]T Let be the attitude angle vector of the UAV. θ and ψ represent the roll, pitch, and yaw angles, respectively; R is the state matrix, and T is the transpose.

[0012]

[0013] State variable X2 = [p, q, r] T Let p be the roll angular velocity vector, q be the pitch angular velocity, r be the yaw angular velocity, pitch angular velocity, and yaw angular velocity; T be the transpose sign; f be a known vector; vector d = [d l ,d m ,d n ] T This is due to the inaccuracy of aerodynamic parameters and the uncertainty caused by wind disturbance during flight;

[0014] The control input vector is u = [l, m, n]. T l, m, and n represent the rolling moment, pitching moment, and yaw moment, respectively; T is the transpose symbol.

[0015] Preferably, the state matrix R is expressed as follows:

[0016]

[0017] Preferably, the vector f is:

[0018]

[0019] Among them, I x I represents the moment of inertia of the UAV in the X-axis direction. y I represents the moment of inertia of the UAV in the Y-axis direction. z The moment of inertia of the UAV in the Z-axis direction is represented by the moment of rotation in the x-axis direction, which is obtained through measurement and estimation; p, q, and r are the roll angular velocities, respectively.

[0020] Preferably, the moment of inertia matrix J is:

[0021]

[0022] Preferably, step 2 involves designing the UAV attitude angular loop control based on a dynamic inverse controller to obtain the expected value X of the attitude angular velocity. 2c The expected value of the attitude angular velocity X 2c for:

[0023] X 2c =R -1 w (6)

[0024] The intermediate vector w for the dynamic inverse control of the attitude angle control loop is:

[0025]

[0026] Among them, X 1c =[φ c ,θ c ,ψ c ] T Let be the desired attitude angle, where the desired roll angle φ is... c Pitch angle θ c and yaw angle ψ c Input from the outside; k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 This is the yaw rate proportional control coefficient.

[0027] Preferably, the angular velocity of the yaw angle for

[0028]

[0029] Where V is airspeed and g is gravitational acceleration.

[0030] Preferably, step 3 is based on the expected value X of the attitude angular velocity. 2c The design of a dynamic inverse controller and interference observer for an unmanned aerial vehicle (UAV) angular velocity loop controller refers to the design of an interference observer to compensate for the effects of uncertainties in the attitude angular velocity model. The formula for the interference observer is as follows:

[0031]

[0032] Where variables Z1, Z2, and Z3 are the state variable X2, the uncertainty d, and the derivative of the uncertainty. The estimated values ​​are λ1, λ2, λ3 and L, which are the observer parameters, and V1 and V2 are the intermediate variables of the interference observer.

[0033] Preferably, the estimated value of the uncertainty d of the disturbance observer is Z2, and the attitude angular velocity control input u of the nonlinear dynamic inverse controller is:

[0034] u = g -1 (vf-Z2) (10)

[0035]

[0036] Where g is the gravitational acceleration; v is the intermediate vector of the attitude angle dynamic inverse control; f is a known vector; Z2 is the estimated value of the disturbance in the attitude angular velocity control loop; X 2c =[p c ,q c ,r c ] T The desired angular velocity, the desired roll angular velocity p c The desired pitch angular velocity q c and the desired yaw rate r c Generated by the attitude angle controller of the outer loop, k p2 k q2 k r2 This is the proportional control coefficient for the attitude angular velocity control loop.

[0037] This invention provides a flight control method for a mountainous oil and gas pipeline inspection UAV. Compared to the traditional PID controller (Proportional-Integral-Derivative controller), this invention employs a dynamic inverse control law to linearize and decouple the system, achieving excellent control performance for high angle-of-attack maneuvers of fixed-wing UAVs. Furthermore, the introduction of a disturbance observer effectively estimates the total disturbance caused by wind disturbance and model uncertainties, compensating for it in the dynamic inverse controller and improving system robustness. Considering the nonlinear characteristics of the system, it effectively addresses the problem that commonly used linear control algorithms cannot meet the requirements for flight robustness.

[0038] According to a second aspect of the present invention, a flight control system for a mountain oil and gas pipeline inspection drone is provided, the system comprising:

[0039] A flight control system for a mountain oil and gas pipeline inspection drone, the system including an attitude angle controller, an angular velocity controller, an interference controller, a state feedback module, and a desired attitude angle module;

[0040] Among them, the attitude angle controller is based on the dynamic inverse controller UAV attitude angle loop control design to obtain the expected value X of the attitude angular velocity. 2c ;

[0041] Among them, the angular velocity controller is based on the expected value X of the attitude angular velocity. 2c The dynamic inverse controller and the interference observer obtain the UAV angular velocity loop controller, thereby obtaining the UAV angular velocity controller;

[0042] This disturbance controller is designed to compensate for the effects of uncertainties in the attitude angular velocity model, and includes an observer.

[0043] The state feedback module is used to obtain the UAV's attitude angle vector and angular velocity vector.

[0044] The desired attitude angle module is used to establish a mathematical model for attitude control in the cruise mode of a vertical take-off and landing fixed-wing UAV and to set the desired attitude angle.

[0045] This system establishes a mathematical model for attitude control of a vertical takeoff and landing fixed-wing UAV in cruise mode; it sets a desired attitude angle, and the attitude angle vector and angular velocity vector of the UAV obtained by the state feedback module are used as inputs to the attitude angle controller; the attitude angle controller is designed based on the dynamic inverse controller for UAV attitude angle loop control, and obtains the desired value X of the attitude angular velocity. 2c Angular velocity controllers are based on the desired value X of the attitude angular velocity. 2c The design of the UAV angular velocity loop controller, which incorporates a dynamic inverse controller and an interference observer, enables flight control of the UAV.

[0046] Preferably, the system establishes a mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV; the desired attitude angle is set, and the UAV's attitude angle vector and angular velocity vector are obtained as inputs to the attitude angle controller. This means that the mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV is established as follows:

[0047]

[0048] Wherein, the state variables X1 = [φ, θ, ψ] T Let be the attitude angle vector of the UAV. θ and ψ represent the roll angle, pitch angle, and yaw angle, respectively; R is the state matrix, and T is the transpose sign;

[0049]

[0050] State variable X2 = [p, q, r] T Let p be the roll angular velocity vector, q be the pitch angular velocity, and r be the yaw angular velocity; T be the transpose sign; f be a known vector; vector d = [d l ,d m ,d n ] T This is due to the inaccuracy of aerodynamic parameters and the uncertainty caused by wind disturbance during flight;

[0051] Wherein, the control input vector u = [l, m, n] T l, m, and n represent the rolling moment, pitching moment, and yaw moment, respectively; T is the transpose symbol.

[0052] The state matrix R is expressed as follows:

[0053]

[0054] Wherein, vector f is:

[0055]

[0056] Among them, I x I represents the moment of inertia of the UAV in the X-axis direction. y I represents the moment of inertia of the UAV in the Y-axis direction. z The moment of inertia of the UAV in the Z-axis direction is represented by the x-axis direction and is obtained through measurement and estimation.

[0057] The moment of inertia matrix J is:

[0058]

[0059] Preferably, the attitude angle controller design is a dynamic inverse UAV attitude angle controller loop control design, which obtains the expected value X of the attitude angular velocity. 2c The expected value of the attitude angular velocity X 2c for:

[0060] X 2c =R -1 w (6)

[0061] The intermediate vector w of the dynamic inverse control in the attitude angle control loop is:

[0062]

[0063] Among them, X 1c =[φ c ,θ c ,ψ c ] T Let be the desired attitude angle, where the desired roll angle φ is... c Pitch angle θ c and yaw angle ψ c Input from the outside; k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 This refers to the yaw rate proportional control coefficient.

[0064] The angular velocity controller is designed for the angular velocity of the yaw angle. for

[0065]

[0066] Where V is airspeed and g is gravitational acceleration;

[0067] The formula for the interference observer is as follows:

[0068]

[0069] Where variables Z1, Z2, and Z3 are the state variable X2, the uncertainty d, and the derivative of the uncertainty. The estimated values ​​are λ1, λ2, λ3 and L, which are the observer parameters, and V1 and V2 are the intermediate variables of the disturbance observer.

[0070] Preferably, the attitude angular velocity control input u of the nonlinear dynamic inverse controller is designed as follows:

[0071] u = g -1 (vf-Z2) (10)

[0072]

[0073] Where g is the gravitational acceleration; v is the intermediate vector for dynamic inverse control of attitude angles; f is a known vector; Z2 is the predicted value; X 2c =[p c ,q c ,r c ] T The desired angular velocity, the desired roll angular velocity p c The desired pitch angular velocity q c and the desired yaw rate r c Generated by the attitude angle controller of the outer loop, k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 This is the yaw rate proportional control coefficient.

[0074] This invention provides a flight control system for a mountainous oil and gas pipeline inspection UAV. Compared to traditional PID controllers (Proportional-Integral-Derivative controllers), this invention employs a dynamic inverse control law for system linearization and decoupling, achieving excellent control performance for high angle-of-attack maneuvers of fixed-wing UAVs. Furthermore, the introduction of a disturbance observer effectively estimates the total disturbance caused by wind disturbances and model uncertainties, compensating for it in the dynamic inverse controller and improving system robustness. Considering the nonlinear characteristics of the system, it effectively addresses the problem that commonly used linear control algorithms cannot meet the requirements for flight robustness.

[0075] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0076] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0077] Figure 1 is a flowchart of a method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas, provided in an embodiment of the present invention.

[0078] Figure 2 is a schematic diagram of a method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas, provided in an embodiment of the present invention.

[0079] Figure 3 is a simulation diagram of the expected roll angle and the actual roll angle of a method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas provided in an embodiment of the present invention.

[0080] Figure 4 is a simulation diagram of the expected pitch angle and the actual pitch angle of a method system for flight control of a UAV for inspecting oil and gas pipelines in mountainous areas, provided in an embodiment of the present invention.

[0081] Figure 5 is a simulation diagram of the actual yaw angle of a method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas provided in an embodiment of the present invention.

[0082] Figure 6 is a simulation diagram of the expected roll angular velocity and the actual roll angular velocity of a method for flight control of a drone for inspecting mountain oil and gas pipelines provided in an embodiment of the present invention.

[0083] Figure 7 is a simulation diagram of the expected pitch angular velocity and the actual pitch angular velocity of a flight control method for a mountain oil and gas pipeline inspection UAV provided in an embodiment of the present invention.

[0084] Figure 8 is a simulation diagram of the expected yaw rate and the actual yaw rate of a flight control method for a mountain oil and gas pipeline inspection UAV provided in an embodiment of the present invention.

[0085] Figure 9 is a simulation diagram of the actual sideslip angle of a method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas, provided in an embodiment of the present invention. Detailed Implementation

[0086] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0087] Example 1

[0088] As shown in Figure 1, this embodiment provides a method for flight control of a drone used for inspecting oil and gas pipelines in mountainous areas. The steps of this method are as follows:

[0089] Step 1: Establish a mathematical model for attitude control of a vertical take-off and landing fixed-wing UAV in cruise mode; set the desired attitude angle, and obtain the UAV attitude angle vector and angular velocity vector as inputs to the attitude angle controller;

[0090] Step 2 involves designing the UAV attitude angle loop control based on a dynamic inverse controller to obtain the expected value X of the attitude angular velocity. 2c ;

[0091] Step 3: Desired value X based on attitude angular velocity 2c The dynamic inverse controller and the interference observer obtain the UAV angular velocity loop controller, thereby obtaining the UAV angular velocity controller.

[0092] In one embodiment, step 1 establishes the mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV as follows:

[0093]

[0094] Wherein, the state variables X1 = [φ, θ, ψ] T Let be the attitude angle vector of the UAV. θ and ψ represent the roll, pitch, and yaw angles, respectively; R is the state matrix, and T is the transpose.

[0095]

[0096] State variable X2 = [p, q, r] T Let p, q, and r be the angular velocity vectors, representing the roll, pitch, and yaw angular velocities, respectively; T is the transpose sign; f is a known vector; vector d = [d l ,d m ,d n ] T This is due to the inaccuracy of aerodynamic parameters and the uncertainty caused by wind disturbance during flight;

[0097] The control input vector is u = [l, m, n]. T l, m, and n represent the rolling moment, pitching moment, and yaw moment, respectively; T is the transpose symbol.

[0098] In one embodiment, the state matrix R is expressed as follows:

[0099]

[0100] In one embodiment, the vector f is:

[0101]

[0102] Among them, I x I y and I z The moment of inertia of the UAV is obtained through measurement and estimation; p, q, and r are the rolling angular velocities, respectively.

[0103] In one embodiment, the moment of inertia matrix J is:

[0104]

[0105] In one embodiment, step 2, based on the dynamic inverse UAV attitude angle controller loop control design, obtains the expected value X of the attitude angular velocity. 2c The expected value of the attitude angular velocity X 2c for:

[0106] X 2c =R -1 w (6)

[0107] The intermediate vector w for the dynamic inverse control of the attitude angle control loop is:

[0108]

[0109] Among them, X 1c =[φ c ,θ c ,ψ c ] T Let be the desired attitude angle, where the desired roll angle φ is... c Pitch angle θ c and yaw angle ψ c Input from the outside; k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 This is the yaw rate proportional control coefficient.

[0110] In one embodiment, the angular velocity of the yaw angle for

[0111]

[0112] Where V is airspeed and g is gravitational acceleration.

[0113] In one embodiment, step 3 is based on the expected value X of the attitude angular velocity. 2c The design of a UAV angular velocity loop controller using dynamic inverse control and an interference observer refers to the design of an interference observer to compensate for the effects of uncertainties in the attitude angular velocity model. The formula for the interference observer is as follows:

[0114]

[0115] Where variables Z1, Z2, and Z3 are the state variable X2, the uncertainty d, and the derivative of the uncertainty. The estimated values ​​are λ1, λ2, λ3 and L, which are the observer parameters, and V1 and V2 are the intermediate variables of the interference observer.

[0116] In one embodiment, the estimated value of the disturbance observer uncertainty d is Z2, and the attitude angular velocity control input u of the nonlinear dynamic inverse controller is:

[0117] u = g -1 (vf-Z2) (10)

[0118]

[0119] Where g is the gravitational acceleration; v is the intermediate vector of the attitude angle dynamic inverse control; f is a known vector; Z2 is the estimated value of the disturbance in the attitude angular velocity control loop; X 2c =[p c ,q c ,r c ] T The desired angular velocity, the desired roll angular velocity p c The desired pitch angular velocity q c and the desired yaw rate r c Generated by the attitude angle controller of the outer loop, k p2 k q2 k r2 This is the proportional control coefficient for the attitude angular velocity control loop.

[0120] This invention provides a flight control method for a mountainous oil and gas pipeline inspection UAV. Compared to traditional PID controllers (Proportional-Integral-Derivative controllers), this invention employs a dynamic inverse control law to linearize and decouple the system, achieving excellent control performance for high angle-of-attack maneuvers of fixed-wing UAVs. Furthermore, the introduction of a disturbance observer effectively estimates the total disturbance caused by wind disturbances and model uncertainties, compensating for it in the dynamic inverse controller and improving system robustness. Considering the nonlinear characteristics of the system, it effectively addresses the problem that commonly used linear control algorithms cannot meet the requirements for flight robustness.

[0121] Example 2

[0122] A method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas, provided by an embodiment of the present invention, is shown in Figure 2. The steps of the method are as follows:

[0123] Step 1: Establish a mathematical model for attitude control of a vertical take-off and landing fixed-wing UAV in cruise mode.

[0124]

[0125]

[0126] Wherein, the state variables X1 = [φ, θ, ψ] T Let p be the UAV attitude angle vector, q be the pitch angular velocity, and r be the yaw angular velocity; the state variable X2 = [p, q, r] T Let be the angular velocity vectors, representing the roll, pitch, and yaw angular velocities, respectively. The control input vector is u = [l, m, n]. T Let R represent the rolling moment, pitching moment, and yaw moment, respectively; R be the state matrix; f be a known vector; and J be the moment of inertia matrix.

[0127] The specific expression is as follows

[0128]

[0129]

[0130]

[0131] Among them, I x I represents the moment of inertia of the UAV in the X-axis direction. y I represents the moment of inertia of the UAV in the Y-axis direction.z The moment of inertia of the UAV in the Z-axis direction is represented by the moment of rotation in the x-axis direction, which is obtained through measurement and estimation.

[0132] Vector d = [d l ,d m ,d n ] T This is due to the inaccuracy of aerodynamic parameters and the uncertainties caused by wind disturbances during flight. In this practical example, the UAV's moment of inertia I... x I y and I z I was obtained through measurement and estimation. x =0.81, I y =1.08, I z =1.82.

[0133] Step 2: Design of UAV Attitude Angle Loop Controller Based on Dynamic Inverse Controller

[0134] Design the control input X based on the nonlinear dynamic inverse controller and formula (1). 2c

[0135] X 2c =R -1 w (6)

[0136]

[0137] Among them, X 1c =[φ c ,θ c ,ψ c ] T Let be the desired attitude angle, where the desired roll angle φ is... c Pitch angle θ c and yaw angle ψ c Input is from the outside. w is the intermediate vector for dynamic inverse control of attitude angle, k p1 k q1 k r1 k is the attitude angle proportional control coefficient, in this practical example p1 =1.5, k q1 =1.5, k r1 =1.5.

[0138] In order to achieve a sideslip angle of 0 during cruise flight and realize coordinated turning, the third term w(3) of the vector w in formula (7) is modified, namely the yaw angle and angular velocity. for

[0139]

[0140] Where V is airspeed and g is gravitational acceleration.

[0141] Step 3: Desired value X based on attitude angular velocity 2c The UAV angular velocity loop controller is obtained by using a dynamic inverse controller and a disturbance observer. To compensate for the uncertainties in the attitude angular velocity model, a disturbance observer is designed, and its formula is as follows:

[0142]

[0143] Where variables Z1, Z2, and Z3 are state variables X2, uncertainty d, and the derivative of uncertainty. The estimated values ​​are λ1, λ2, λ3, and L, which are the observer parameters. In this practical example, based on empirical values, λ1 = 30, λ2 = 300, λ3 = 1000, and L = 0.02.

[0144] Based on the estimated value Z2 of the uncertainty d in the disturbance observer formula (9), and the nonlinear dynamic inverse controller design of the attitude angular velocity control input u

[0145] u = g -1 (vf-Z2) (10)

[0146]

[0147] Among them, X 2c =[p c ,q c ,r c ] T The desired angular velocity is obtained from step two, where the desired roll angular velocity p c The desired pitch angular velocity q c and the desired yaw rate r c It is generated by the attitude angle controller of the outer loop. v is the intermediate vector of the dynamic inverse control of the attitude angle.

[0148] k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 The yaw rate proportional control coefficient is set by k based on experience in this practical example. p2 =7,k q2 =7,k r2 =7.

[0149] Next, the simulation time was set to 10 seconds, and the desired roll and pitch angles were set to 0.13 rad. The simulation results are shown in Figures 2 to 9.

[0150] Based on the flight control method of a mountain oil and gas pipeline inspection drone described in the embodiment corresponding to Figure 1 above, the following is a system embodiment of this disclosure.

[0151] This invention provides a flight control method for a mountainous oil and gas pipeline inspection UAV. Compared to the traditional PID controller (Proportional-Integral-Derivative controller), this invention employs a dynamic inverse control law to linearize and decouple the system, achieving excellent control performance for high angle-of-attack maneuvers of fixed-wing UAVs. Furthermore, the introduction of a disturbance observer effectively estimates the total disturbance caused by wind disturbance and model uncertainties, compensating for it in the dynamic inverse controller and improving system robustness. Considering the nonlinear characteristics of the system, it effectively addresses the problem that commonly used linear control algorithms cannot meet the requirements for flight robustness.

[0152] Example 3

[0153] This embodiment provides a flight control system for a mountain oil and gas pipeline inspection drone. The system includes an attitude angle controller, an angular velocity controller, an interference controller, a status feedback module, and a desired attitude angle module.

[0154] Among them, the attitude angle controller is based on the dynamic inverse controller UAV attitude angle loop control design to obtain the expected value X of the attitude angular velocity. 2c ;

[0155] Among them, the angular velocity controller is a UAV angular velocity loop controller designed based on a dynamic inverse controller and an interference observer, thereby realizing the flight control of the UAV;

[0156] This disturbance controller is designed to compensate for the effects of uncertainties in the attitude angular velocity model, and includes an observer.

[0157] The state feedback module is used to obtain the UAV's attitude angle vector and angular velocity vector.

[0158] This desired attitude angle module is used to establish a mathematical model for attitude control in the cruise mode of a vertical takeoff and landing (VTOL) fixed-wing UAV. The system establishes this mathematical model by setting the desired attitude angle. The attitude angle vector and angular velocity vector obtained by the state feedback module are used as inputs to the attitude angle controller. The attitude angle controller is designed based on a dynamic inverse controller for UAV attitude angle loop control, obtaining the desired value X of the attitude angular velocity. 2c The output of the attitude angle controller is the input of the angular velocity controller, which is based on the expected value X of the attitude angular velocity. 2cThe dynamic inverse controller and the interference observer obtain the UAV angular velocity loop controller, thereby obtaining the UAV angular velocity controller.

[0159] In one embodiment, the system establishes a mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV; the desired attitude angle is set, and the UAV attitude angle vector and angular velocity vector are obtained as inputs to the attitude angle controller. This means that the mathematical model for attitude control in the cruise mode of the vertical takeoff and landing fixed-wing UAV is established as follows:

[0160]

[0161] Wherein, the state variables X1 = [φ, θ, ψ] T Let be the attitude angle vector of the UAV. θ and ψ represent the roll angle, pitch angle, and yaw angle, respectively; R is the state matrix, and T is the transpose sign;

[0162]

[0163] State variable X2 = [p, q, r] T Let p be the roll angular velocity vector, q be the pitch angular velocity, and r be the yaw angular velocity; T be the transpose sign; f be a known vector; vector d = [d l ,d m ,d n ] T This is due to the inaccuracy of aerodynamic parameters and the uncertainty caused by wind disturbance during flight;

[0164] Wherein, the control input vector u = [l, m, n] T l represents the roll moment, m represents the pitch moment, and n represents the yaw moment; T is the transpose symbol;

[0165] The state matrix R is expressed as follows:

[0166]

[0167] Wherein, vector f is:

[0168]

[0169] Among them, I x I represents the moment of inertia of the UAV in the X-axis direction. y I represents the moment of inertia of the UAV in the Y-axis direction. z The moment of inertia of the UAV in the Z-axis direction is represented by the moment of rotation in the x-axis direction, which is obtained through measurement and estimation; p, q, and r are the roll angular velocities, respectively.

[0170] The moment of inertia matrix J is:

[0171]

[0172] In one embodiment, the attitude angle controller design is based on a dynamic inverse UAV attitude angle controller loop control design to obtain the expected value X of the attitude angular velocity. 2c The expected value of the attitude angular velocity X 2c for:

[0173] X 2c =R -1 w (6)

[0174] The intermediate vector w of the dynamic inverse control in the attitude angle control loop is:

[0175]

[0176] Among them, X 1c =[φ c ,θ c ,ψ c ] T Let be the desired attitude angle, where the desired roll angle φ is... c Pitch angle θ c and yaw angle ψ c Input from the outside; k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 This refers to the yaw rate proportional control coefficient.

[0177] The angular velocity controller is designed for the angular velocity of the yaw angle. for

[0178]

[0179] Where V is airspeed and g is gravitational acceleration;

[0180] The formula for the interference observer is as follows:

[0181]

[0182] Where variables Z1, Z2, and Z3 are the state variable X2, the uncertainty d, and the derivative of the uncertainty. The estimated values ​​are λ1, λ2, λ3 and L, which are the observer parameters, and V1 and V2 are the intermediate variables of the disturbance observer.

[0183] In one embodiment, the attitude angular velocity control input u of the nonlinear dynamic inverse controller is designed as follows:

[0184] u = g -1 (vf-Z2)(10)

[0185]

[0186] Where g is the gravitational acceleration; v is the intermediate vector for dynamic inverse control of attitude angles; f is a known vector; Z2 is the predicted value; X 2c =[p c ,q c ,r c ] T The desired angular velocity, the desired roll angular velocity p c The desired pitch angular velocity q c and the desired yaw rate r c Generated by the attitude angle controller of the outer loop, k p1 For the proportional control coefficient of roll angular velocity, k q1 For pitch angular velocity proportional control coefficient, k r1 This is the yaw rate proportional control coefficient.

[0187] This invention provides a flight control system for a mountainous oil and gas pipeline inspection UAV. Compared to traditional PID controllers (Proportional-Integral-Derivative controllers), this invention employs a dynamic inverse control law for system linearization and decoupling, achieving excellent control performance for high angle-of-attack maneuvers of fixed-wing UAVs. Furthermore, the introduction of a disturbance observer effectively estimates the total disturbance caused by wind disturbances and model uncertainties, compensating for it in the dynamic inverse controller and improving system robustness. Considering the nonlinear characteristics of the system, it effectively addresses the problem that commonly used linear control algorithms cannot meet the requirements for flight robustness.

Claims

1. A method for flight control of a drone used for inspecting oil and gas pipelines in mountainous areas, applied to drones, characterized in that, The method includes the following steps: Step 1: Establish a mathematical model for attitude control in the cruise mode of a vertical take-off and landing fixed-wing UAV; set the desired attitude angle, and obtain the UAV attitude angle vector and angular velocity vector as inputs to the attitude angle controller; the mathematical model for attitude control is: (1) Among them, state variables Let ø, θ, and ψ be the attitude angle vectors of the UAV, where ø, θ, and ψ are the roll angle, pitch angle, and yaw angle, respectively. Here, T is the state matrix, and T is the transpose symbol. (2) State variables denoted as angular velocity vector, where p is the roll angular velocity, q is the pitch angular velocity, and r is the yaw angular velocity; T is the transpose sign. The vector is known; For gravitational acceleration, vector Due to the inaccuracy of aerodynamic parameters and the uncertainty caused by wind disturbance during flight; control input vector Where l represents the roll moment, m represents the pitch moment, and n represents the yaw moment; T represents the transpose sign; Step 2: Design the UAV attitude angle loop control based on the dynamic inverse controller to obtain the expected value of the attitude angular velocity. The expected value of the attitude angular velocity for: (6) Attitude angle control loop dynamic inverse control intermediate vector for: (7) Among them, Let be the desired attitude angle, where the desired roll angle is . Pitch angle and yaw angle Input from the outside; For the proportional control coefficient of roll angular velocity, For pitch angular velocity proportional control coefficient, The yaw rate proportional control coefficient; Step 3: Based on the expected value of the attitude angular rate. The UAV angular velocity loop controller is obtained by using a dynamic inverse controller and an interference observer. The UAV angular velocity loop controller is designed to compensate for uncertainties in the attitude angular velocity model. The interference observer's formula is as follows: (9) Among them, variables ， ， These are state variables. Uncertainty Derivatives of uncertainty The estimated value, ， ， and V1 and V2 are the observer parameters, and V1 and V2 are the intermediate variables of the interference observer.

2. The method for flight control of a UAV for inspecting oil and gas pipelines in mountainous areas according to claim 1, characterized in that, The state matrix The expression is, (3) The vector for: (4) Among them, This is expressed as the moment of inertia of the UAV in the X-axis direction. This is expressed as the moment of inertia of the UAV in the Y-axis direction. The moment of inertia of the UAV along the Z-axis is obtained through measurement and estimation; the moment of inertia matrix for: （5）。 3. The method for flight control of a UAV for inspecting oil and gas pipelines in mountainous areas according to claim 1, characterized in that, The angular velocity of the yaw angle for: (8) Among them, Airspeed, This is the acceleration due to gravity.

4. The method for flight control of a drone for inspecting oil and gas pipelines in mountainous areas according to claim 1, characterized in that, The uncertainty of the interference observer The estimated value Attitude angular velocity control input based on nonlinear dynamic inverse controller for: （10） (11) Where g is the acceleration due to gravity; confirm correctness. f is the intermediate vector for dynamic inverse control of attitude angles; f is a known vector. The estimated value of the disturbance in the attitude angular velocity control loop; The desired angular velocity, the desired roll angular velocity Desired pitch angular velocity and the desired yaw rate Generated by the attitude angle controller of the outer loop. For the proportional control coefficient of roll angular velocity, For pitch angular velocity proportional control coefficient, This is the yaw rate proportional control coefficient.

5. A flight control system for implementing the flight control method of the mountain oil and gas pipeline inspection UAV according to any one of claims 1-4, characterized in that, The system includes an attitude angle controller, an angular velocity controller, a disturbance observer, a state feedback module, and a desired attitude angle module. The attitude angle controller is based on a dynamic inverse controller UAV attitude angle loop control design to obtain the desired value of the attitude angular velocity. The angular velocity controller is based on the expected value of the attitude angular velocity. The UAV angular velocity loop controller is obtained by using a dynamic inverse controller and an interference observer; the interference observer is designed to compensate for the influence of uncertainties in the attitude angular velocity model of the attitude angular controller. The state feedback module is used to acquire the UAV attitude angle vector and angular velocity vector; the desired attitude angle module is used to establish a mathematical model for attitude control in the cruise mode of a vertical take-off and landing fixed-wing UAV and set the desired attitude angle; the system establishes a mathematical model for attitude control in the cruise mode of a vertical take-off and landing fixed-wing UAV; sets the desired attitude angle, and the UAV attitude angle vector and angular velocity vector acquired by the state feedback module are used as inputs to the attitude angle controller; the attitude angle controller is designed based on a dynamic inverse controller for UAV attitude angle loop control, and obtains the desired value of the attitude angular velocity. The output of the attitude angle controller is the input of the angular velocity controller, which is based on the expected value of the attitude angular velocity. The dynamic inverse controller and the interference observer obtain the UAV angular velocity loop controller, thereby obtaining the UAV angular velocity controller.

6. The flight control system according to claim 5, characterized in that, The system establishes a mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV; it sets the desired attitude angle and obtains the UAV's attitude angle vector and angular velocity vector, which serve as the inputs to the attitude angle controller. This means that the mathematical model for attitude control in the cruise mode of a vertical takeoff and landing fixed-wing UAV is as follows: (1) Among them, state variables Let ø, θ, and ψ be the attitude angle vectors of the UAV, where ø, θ, and ψ are the roll angle, pitch angle, and yaw angle, respectively. Here, T is the state matrix, and T is the transpose symbol. (2) State variables denoted as angular velocity vector, where p is the roll angular velocity, q is the pitch angular velocity, and r is the yaw angular velocity; T is the transpose sign. A known vector; a vector Due to the inaccuracy of aerodynamic parameters and the uncertainty caused by wind disturbance during flight; control input vector Where l represents the roll moment, m represents the pitch moment, and n represents the yaw moment; T represents the transpose symbol; the state matrix The expression is, (3) The vector for: (4) Among them, This is expressed as the moment of inertia of the UAV in the X-axis direction. This is expressed as the moment of inertia of the UAV in the Y-axis direction. The moment of inertia of the UAV in the Z-axis direction is represented by the moment of inertia in the x-axis direction, obtained through measurement and estimation; the moment of inertia matrix for: （5） 。 7. The flight control system according to claim 5, characterized in that, The attitude angle controller is designed based on the dynamic inverse UAV attitude angle controller loop control design to obtain the expected value of the attitude angular velocity. The expected value of the attitude angular velocity for: (6) Attitude angle control loop dynamic inverse control intermediate vector for: (7) Among them, Let be the desired attitude angle, where the desired roll angle is . Pitch angle and yaw angle Input from the outside; For the proportional control coefficient of roll angular velocity, For pitch angular velocity proportional control coefficient, This refers to the proportional control coefficient for yaw rate; the angular velocity controller is designed to measure the angular velocity of the yaw angle. for: (8) Among them, Airspeed, Let gravitational acceleration be the acceleration due to gravity; the formula for the disturbance observer is as follows: (9) Among them, variables ， ， It is a state variable Uncertainty Derivatives of uncertainty The estimated value, ， ， and V1 and V2 are the observer parameters, and V1 and V2 are intermediate variables of the disturbance observer; the attitude angular velocity control input is designed based on a nonlinear dynamic inverse controller. for: （10） (11) Where g is the acceleration due to gravity; Z1 is the intermediate vector for dynamic inverse control of attitude angle; f is a known vector; Z2 is the estimated value. The desired angular velocity, the desired roll angular velocity Desired pitch angular velocity and the desired yaw rate Generated by the attitude angle controller of the outer loop. For the proportional control coefficient of roll angular velocity, For pitch angular velocity proportional control coefficient, This is the yaw rate proportional control coefficient.

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