An attitude control method and system for an amphibious dual-rotor unmanned aerial vehicle (UAV).

Abstract

This invention discloses an attitude control method and system for an amphibious dual-rotor unmanned aerial vehicle (UAV). By solving the control input of the UAV sliding mode controller through the UAV's mechanical model, angular velocity model, and sliding mode controller's sliding surface mathematical model, the method achieves precise attitude control of the dual-rotor UAV system by optimizing the control input. This enables precise hovering, smooth take-off and landing, and excellent attitude control performance. It effectively addresses the uncertainties of the system model and time-varying environmental effects, improves the robustness and stability of the system in complex environments, and solves the technical problems of poor adaptability and low robustness of existing attitude control methods for amphibious dual-rotor UAVs under environmental changes.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to an attitude control method and system for an amphibious dual-rotor UAV. Background Technology

[0002] Unmanned aerial vehicle (UAV) technology is widely used in various fields, including agriculture, aerial photography, and emergency rescue. However, for amphibious operations, UAVs still face challenges in navigation (both in the air and in the water). Amphibious dual-rotor UAVs, with only two rotors, exhibit relatively poor stability. Existing attitude control methods for amphibious dual-rotor UAVs include: classical PID control strategies, applied switching control methods, adaptive algorithm-aided design of globally continuous nonlinear controllers, and dynamic control methods based on disturbance observers. However, existing attitude control methods for amphibious dual-rotor UAVs have poor adaptability and low robustness to environmental changes. Therefore, improving the robustness and stability of amphibious dual-rotor UAVs in complex environments is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0003] This invention provides an attitude control method and system for an amphibious dual-rotor unmanned aerial vehicle (UAV), which addresses the technical problems of poor adaptability and low robustness of existing attitude control methods for amphibious dual-rotor UAVs when facing environmental changes.

[0004] In view of this, the first aspect of the present invention provides an attitude control method for an amphibious dual-rotor unmanned aerial vehicle, comprising:

[0005] Establish a ground coordinate system and a UAV body coordinate system;

[0006] Based on the ground coordinate system and the UAV body coordinate system, a three-axis torque model and a UAV torque kinematic model are constructed.

[0007] Define the UAV body angular velocity model and the UAV body angular velocity error model;

[0008] Based on the UAV torque kinematics model, UAV body angular velocity model, and UAV body angular velocity error model, a dynamic model based on angular velocity error is constructed.

[0009] Construct a mathematical model of the sliding surface for a sliding mode controller for an unmanned aerial vehicle (UAV);

[0010] Based on the dynamic model and sliding surface mathematical model based on angular velocity error, the control input of the UAV sliding mode controller is solved;

[0011] The three-axis torque model of the UAV is solved based on the control input to obtain the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the UAV.

[0012] The attitude control of the drone is achieved by using the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the drone.

[0013] Optionally, the three-axis torque model of the UAV is as follows:

[0014]

[0015] Among them, M P1 Let M be the torque of the UAV in the x-axis direction of the UAV's body coordinate system. P2 Let M be the torque of the UAV in the y-axis direction of the UAV's body coordinate system. P3 Let be the torque of the UAV along the z-axis of the UAV's body coordinate system; d is the horizontal distance between the points of application of the lift forces of the two UAV rotors and the UAV's center of gravity; h is the vertical distance between the points of application of the lift forces of the two UAV rotors and the UAV's center of gravity; T1 is the lift provided by the left rotor of the UAV; T2 is the lift provided by the right rotor of the UAV; C m ω1 is the torque coefficient of the motor, ω2 is the rotational speed of the left rotor motor of the drone, θ1 is the deflection angle of the left rotor motor of the drone, and θ2 is the deflection angle of the right rotor motor of the drone.

[0016] Alternatively, the kinematic model of the UAV torque is as follows:

[0017]

[0018] Where J is the moment of inertia, M is the net torque acting on the UAV body, d is the disturbance torque, and Ω b Let be the angular velocity of the UAV in the UAV's body coordinate system. Differentiate the angular velocity of the UAV in the UAV's body coordinate system, k d This is the coefficient matrix of the resistance force encountered during rotation.

[0019] Optionally, the angular velocity model of the UAV body is:

[0020] Ω c =α c arctan(α a E q )

[0021] α c =diag(α) c1 α c2 α c3 )

[0022] α a =diag(α) a1 α a2 α a3 )

[0023] E q =2q e,0 q e,v

[0024] Among them, Ω c For the desired angular velocity of the organism, α c α is the first adjustable coefficient. c1 For α c x-axis component, α c2 For α c The y-axis component, α c3 For α c z-axis component, α a α is the second adjustable coefficient. a1 For α a x-axis component, α a2 For α a The y-axis component, α a3 For α a The z-axis component, E q Let q be the correlation coefficient. e,0 Let q be the real part of the attitude error. e,v This represents the imaginary part of the attitude error;

[0025] The UAV body angular velocity error model is as follows:

[0026] Ω e =Ω b -Ω c

[0027] Among them, Ω e This represents the expected angular velocity error of the machine body.

[0028] Alternatively, the dynamic model based on angular velocity error is:

[0029]

[0030] in, Differentiate the desired angular velocity error of the organism.

[0031] Optionally, the mathematical model of the sliding surface of the UAV sliding mode controller is as follows:

[0032]

[0033] E q =[a1 a2 a3] T α3=[l1 l2 l3] T

[0034] Where s is the sliding surface, α1, α2, and α3 are all three-dimensional column vectors, β0 is a coefficient greater than 1, γ(·) is the operation function, and a1, a2, and a3 are E qThe triaxial coefficients are l1, l2, and l3, which are the triaxial coefficients of α3.

[0035] Optionally, based on the dynamic model and sliding surface mathematical model based on angular velocity error, the control input of the UAV sliding mode controller is solved, including:

[0036] Differentiate the mathematical model of the sliding surface and configure the sliding surface reaching law of the UAV sliding surface controller;

[0037] By setting the derivative of the sliding surface mathematical model to 0 and the sliding surface reaching law to 0, and by combining the dynamic model based on the angular velocity error and the sliding surface mathematical model, the resultant torque on the UAV body is solved, and the control input of the UAV sliding mode controller is obtained.

[0038] A second aspect of the present invention provides an attitude control system for an amphibious dual-rotor unmanned aerial vehicle, comprising:

[0039] The coordinate system construction module is used to establish the ground coordinate system and the UAV body coordinate system;

[0040] The first modeling module is used to construct the three-axis torque model and the torque kinematics model of the UAV based on the ground coordinate system and the UAV body coordinate system.

[0041] The second modeling module is used to define the UAV body angular velocity model and the UAV body angular velocity error model;

[0042] The third modeling module is used to construct a dynamic model based on angular velocity error, based on the UAV torque kinematics model, the UAV body angular velocity model, and the UAV body angular velocity error model.

[0043] The fourth modeling module is used to construct the mathematical model of the sliding surface of the UAV sliding mode controller;

[0044] The first solution module is used to solve for the control input of the UAV sliding mode controller based on the dynamic model and the sliding surface mathematical model based on the angular velocity error.

[0045] The second solution module is used to solve the three-axis torque model of the UAV based on the control input, and obtain the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the UAV.

[0046] The attitude control module is used to control the attitude of the drone based on the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the drone.

[0047] Optionally, the first solver module is specifically used for:

[0048] Differentiate the mathematical model of the sliding surface and configure the sliding surface reaching law of the UAV sliding surface controller;

[0049] By setting the derivative of the sliding surface mathematical model to 0 and the sliding surface reaching law to 0, and by combining the dynamic model based on the angular velocity error and the sliding surface mathematical model, the resultant torque on the UAV body is solved, and the control input of the UAV sliding mode controller is obtained.

[0050] Optionally, the three-axis torque model of the UAV is as follows:

[0051]

[0052] Among them, M P1 Let M be the torque of the UAV in the x-axis direction of the UAV's body coordinate system. P2 Let M be the torque of the UAV in the y-axis direction of the UAV's body coordinate system. P3 Let be the torque of the UAV along the z-axis of the UAV's body coordinate system; d is the horizontal distance between the points of application of the lift forces of the two UAV rotors and the UAV's center of gravity; h is the vertical distance between the points of application of the lift forces of the two UAV rotors and the UAV's center of gravity; T1 is the lift provided by the left rotor of the UAV; T2 is the lift provided by the right rotor of the UAV; C m ω1 is the torque coefficient of the motor, ω2 is the rotational speed of the left rotor motor of the drone, θ1 is the deflection angle of the left rotor motor of the drone, and θ2 is the deflection angle of the right rotor motor of the drone.

[0053] Alternatively, the kinematic model of the UAV torque is as follows:

[0054]

[0055] Where J is the moment of inertia, M is the net torque acting on the UAV body, d is the disturbance torque, and Ω b Let be the angular velocity of the UAV in the UAV's body coordinate system. Differentiate the angular velocity of the UAV in the UAV's body coordinate system, k d This is the coefficient matrix of the resistance force encountered during rotation.

[0056] Optionally, the angular velocity model of the UAV body is:

[0057] Ω c =α c arctan(α a E q )

[0058] α c =diag(α) c1 α c2 α c3 )

[0059] α a =diag(α) a1 α a2 αa3 )

[0060] E q =2q e,0 q e,v

[0061] Among them, Ω c For the desired angular velocity of the organism, α c α is the first adjustable coefficient. c1 For α c x-axis component, α c2 For α c The y-axis component, α c3 For α c z-axis component, α a α is the second adjustable coefficient. a1 For α a x-axis component, α a2 For α a The y-axis component, α a3 For α a The z-axis component, E q Let q be the correlation coefficient. e,0 Let q be the real part of the attitude error. e,v This represents the imaginary part of the attitude error;

[0062] The UAV body angular velocity error model is as follows:

[0063] Ω e =Ω b -Ω c

[0064] Among them, Ω e This represents the expected angular velocity error of the machine body.

[0065] Alternatively, the dynamic model based on angular velocity error is:

[0066]

[0067] in, Differentiate the desired angular velocity error of the organism.

[0068] Optionally, the mathematical model of the sliding surface of the UAV sliding mode controller is as follows:

[0069]

[0070] E q =[a1 a2 a3] T α3=[l1 l2 l3] T

[0071] Where s is the sliding surface, α1, α2, and α3 are all three-dimensional column vectors, β0 is a coefficient greater than 1, γ(·) is the operation function, and a1, a2, and a3 are E q The triaxial coefficients are l1, l2, and l3, which are the triaxial coefficients of α3.

[0072] As can be seen from the above technical solutions, the attitude control method for an amphibious dual-rotor UAV provided by the present invention has the following advantages:

[0073] The attitude control method for an amphibious dual-rotor UAV provided by this invention solves for the control input of the UAV sliding mode controller by using the UAV's mechanical model, angular velocity model, and sliding mode controller's sliding surface mathematical model. By optimizing the control input, precise attitude control of the dual-rotor UAV system is achieved, enabling precise hovering, smooth take-off and landing, and good attitude control performance. It effectively addresses the uncertainties of the system model and time-varying environmental effects, improves the robustness and stability of the system in complex environments, and solves the technical problems of poor adaptability and low robustness of existing attitude control methods for amphibious dual-rotor UAVs under environmental changes. Attached Figure Description

[0074] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0075] Figure 1 This is a flowchart illustrating an attitude control method for an amphibious dual-rotor unmanned aerial vehicle provided in an embodiment of the present invention.

[0076] Figure 2 The response curves of the three-axis attitude angles when following a sine wave were obtained by simulating and verifying the attitude control method of the amphibious dual-rotor UAV provided in the embodiments of the present invention.

[0077] Figure 3 The image shows a comparison of the expected pitch angle and the response when following a sine wave, obtained from the simulation verification of the attitude control method of the amphibious dual-rotor UAV provided in the embodiments of the present invention.

[0078] Figure 4 The response curves of the three-axis attitude angles when following a step wave were obtained by simulating and verifying the attitude control method of the amphibious dual-rotor UAV provided in the embodiments of the present invention.

[0079] Figure 5The image shows a comparison of the expected pitch angle and the response when following a step wave, obtained from the simulation verification of the attitude control method of the amphibious dual-rotor UAV provided in the embodiments of the present invention.

[0080] Figure 6 This is a schematic diagram of the attitude control system of an amphibious dual-rotor unmanned aerial vehicle provided in an embodiment of the present invention. Detailed Implementation

[0081] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0082] For easier understanding, please refer to Figure 1 This invention provides an embodiment of an attitude control method for an amphibious dual-rotor unmanned aerial vehicle, comprising:

[0083] Step 101: Establish the ground coordinate system and the UAV body coordinate system.

[0084] It should be noted that two coordinate systems conforming to the right-hand rule are first established. The first is the UAV body coordinate system: the origin of the UAV body coordinate system is located at the aircraft's center of gravity, and the x, y, and z axes point forward, right, and ground, respectively. The second is the ground coordinate system: the origin of the ground coordinate system is taken from the flight control command center, and the x, y, and z axes point north, east, and ground, respectively.

[0085] Step 102: Based on the ground coordinate system and the UAV body coordinate system, construct the UAV three-axis torque model and the UAV torque kinematic model.

[0086] It should be noted that the attitude control of the dual-rotor drone relies on two vector motors located on the left and right sides of the top of the drone. The power provided by the motors and the rotational torque of the motors are expressed as follows:

[0087]

[0088] Where T1 is the lift provided by the left rotor of the drone, T2 is the lift provided by the right rotor of the drone, ω1 is the rotational speed of the left rotor motor of the drone, ω2 is the rotational speed of the right rotor motor of the drone, and c t c is the motor lift coefficient. c τ1 is the torque coefficient of the motor, τ2 is the rotational torque of the left rotor motor of the UAV, and τ3 is the rotational torque of the right rotor motor of the UAV.

[0089] The three-axis torque of a drone is determined by the motor thrust and the motor deflection angle. Therefore, the three-axis torque model of a drone can be expressed as:

[0090]

[0091] Among them, M P1 Let M be the torque of the UAV in the x-axis direction of the UAV's body coordinate system. P2 Let M be the torque of the UAV in the y-axis direction of the UAV's body coordinate system. P3 Let be the torque of the UAV along the z-axis of the UAV's body coordinate system; d is the horizontal distance between the two rotor lift points and the UAV's center of gravity; h is the vertical distance between the two rotor lift points and the UAV's center of gravity; θ1 is the deflection angle of the left rotor motor; θ2 is the deflection angle of the right rotor motor; θ1 and θ2 are positive for backward deflection and negative for forward deflection; C m This represents the motor's torque coefficient. The motor's rotational torque has a relatively small impact on the torque along the x and y axes, and is considered a minor control disturbance, thus included in the model's disturbance. Therefore, the above three-axis torque model for the UAV can be simplified as follows:

[0092]

[0093] The kinematic model of the UAV torque can be expressed as:

[0094]

[0095] Where J is the moment of inertia, M is the net torque acting on the UAV body, d is the disturbance torque, and Ω b Let be the angular velocity of the UAV in the UAV's body coordinate system. Differentiate the angular velocity of the UAV in the UAV's body coordinate system, k d This is the coefficient matrix of the resistance force encountered during rotation.

[0096] The control algorithm designed in this invention is for the attitude control of UAVs. The torque kinematic model of the UAV is explained as follows:

[0097]

[0098] J = diag(J) xx J yy J zz )

[0099] k d =diag(k) dx k dy k dz )

[0100] M = (I x I y Iz ) T

[0101] d=(d x d y d z ) T

[0102] Where, d x d y d z These are the components of the disturbance torque along the three axes of the UAV's body coordinate system, J. xx J yy J zz These are the diagonal elements of the moment of inertia matrix, k dx k dy k dz These are the diagonal elements of the coefficient matrix of the resistance to rotation, I. x I y I z These are the components of the resultant torque acting on the UAV body along the three axes of the system.

[0103] Because Euler angles have limitations in representing rotational motion, such as gimbal lock and singularities, this invention represents the UAV torque kinematics model in the form of quaternions. A quaternion is a mathematical object used to describe rotation in three-dimensional space. A quaternion consists of one real part and three imaginary parts; q0 is the real part of the quaternion, q... v The imaginary part of a quaternion is usually represented in the following form:

[0104] q v =[q1q2 q3] T

[0105] Where q is a quaternion, and q1, q2, and q3 are the three components of the imaginary part of the quaternion q.

[0106] The quaternion q satisfies the following relationship:

[0107]

[0108] The real part of a quaternion represents the angle of rotation, and the imaginary part represents the direction of the rotation axis. Quaternion multiplication and the inverse of a quaternion are represented as follows:

[0109]

[0110] Where, q a Let q be the first quaternion. b Let q be the second quaternion. a,0 q is a quaternion a The real part, q b,0 q is a quaternionb The real part, q a,v q is a quaternion a The imaginary part, q b,v q is a quaternion b The imaginary part, For q a,v The transpose of .

[0111] Representing the torque kinematics model of the UAV using quaternions and performing calculations according to the rules of quaternion arithmetic, we have:

[0112]

[0113] in,[·] × I is the cross product factor, and I3 is the 3rd order identity matrix.

[0114] The rules for cross product factors are as follows:

[0115]

[0116] Where b is a defined vector, and b1, b2, and b3 are the three components of b.

[0117] Step 103: Define the UAV body angular velocity model and the UAV body angular velocity error model.

[0118] It should be noted that when designing a sliding mode controller for attitude control of an unmanned aerial vehicle (UAV), the sliding surface is designed based on the system tracking error, which is defined by the following formula:

[0119]

[0120] Where, q c It is the desired posture, q e Q is the attitude error, and Q is the current attitude, both represented as quaternions.

[0121] Based on the calculation method of quaternion inverse, the attitude error is expressed as follows:

[0122]

[0123] For the desired posture q c and attitude error q e Their first derivatives are expressed in the same way:

[0124]

[0125] Among them, Ω c For the desired angular velocity of the organism, Ω e For the desired body angular velocity error, q c,0 For the desired posture q c The real part, For the desired posture q c Differentiate the real part of q c,v For the desired posture q c The imaginary part, For the desired posture q c Differentiate the imaginary part. Let q be the attitude error. e Differentiate the real part of q e,v Let q be the attitude error. e The imaginary part, Let q be the attitude error. e Differentiate the imaginary part of q e,0 Let q be the attitude error. e The real part.

[0126] The relationship between angular velocity error and desired angular velocity is consistent with the relationship between attitude quaternions. The UAV body angular velocity error model can be expressed as:

[0127] Ω e =Ω b -Ω c

[0128] In this invention, the UAV body angular velocity model for obtaining the UAV body angular velocity is defined as follows:

[0129] Ω c =α c arctan(α a E q )

[0130] α c =diag(α) c1 α c2 α c3 )

[0131] α a =diag(α) a1 α a2 α a3 )

[0132] E q =2q e,0 q e,v

[0133] Among them, Ω c For the desired angular velocity of the organism, α c α is the first adjustable coefficient. c1 For α c x-axis component, α c2 For α c The y-axis component, α c3 For α c z-axis component, α aα is the second adjustable coefficient. a1 For α a x-axis component, α a2 For α a The y-axis component, α a3 For α a The z-axis component, E q Let q be the correlation coefficient. e,0 Let q be the real part of the attitude error. e,v This represents the imaginary part of the attitude error.

[0134] Step 104: Construct a dynamic model based on angular velocity error, according to the UAV torque kinematic model, UAV body angular velocity model, and UAV body angular velocity error model.

[0135] It should be noted that, based on the representations of the UAV torque kinematics model, the UAV body angular velocity model, and the UAV body angular velocity error model, a dynamic model based on angular velocity error can be established:

[0136]

[0137] in, Differentiate the desired angular velocity error of the organism.

[0138] Step 105: Construct the mathematical model of the sliding surface of the UAV sliding mode controller.

[0139] It should be noted that the sliding mode controller design follows the basic controller design approach. First, a mathematical model of the UAV platform is performed. Then, based on the system model and system characteristics, an appropriate sliding surface and reaching law are designed. Finally, the control input is calculated based on the system model and sliding surface. To achieve stable flight and accurate control of the dual-rotor UAV, a sliding mode controller is designed to implement attitude control. The control input is the motor torque, determined by the rotational speed ω and the motor deflection angle θ. Precise attitude control of the dual-rotor UAV system is achieved by optimizing the motor control input. In this embodiment of the invention, the mathematical model of the sliding surface of the UAV sliding mode controller is as follows:

[0140]

[0141] E q =[a1 a2 a3] T α3=[l1 l2 l3] T

[0142] Where s is the sliding surface, α1, α2, and α3 are all three-dimensional column vectors, β0 is a coefficient greater than 1, γ(·) is the operation function, and a1, a2, and a3 are E q The triaxial coefficients are l1, l2, and l3, which are the triaxial coefficients of α3.

[0143] Since the sliding surface s is a three-dimensional vector, it can be represented as:

[0144] s = [s1 s2 s3] T

[0145] Among them, s1, s2, and s3 are the three components of the sliding surface s.

[0146] Step 106: Based on the dynamic model and sliding surface mathematical model based on angular velocity error, solve for the control input of the UAV sliding mode controller.

[0147] It should be noted that the control input needs to be calculated based on the design of the sliding surface and the mathematical model of the UAV. First, taking the derivative of the sliding surface s, we have:

[0148]

[0149] The sliding surface reaching law for configuring the UAV sliding mode controller is as follows:

[0150]

[0151] Where, α γ Let be a three-dimensional column vector, and sgn(s) be the sign function of the three components of the sliding surface, with positive components being 1 and negative components being -1. Dsgn(s) is a piecewise function that limits the magnitude of the disturbance torque d. If the magnitude is less than d, it remains unchanged; if it is greater than d, the magnitude is reduced.

[0152] By setting the derivative of the sliding surface mathematical model to 0 and the sliding surface reaching law to 0, and simultaneously solving the dynamic model based on angular velocity error and the sliding surface mathematical model, the resultant torque acting on the UAV body is obtained, thus yielding the control input for the UAV sliding mode controller. Specifically:

[0153] make Then join together and Ω e =Ω b -Ω c The control input M of the UAV sliding mode controller can be obtained as follows:

[0154]

[0155] Step 107: Solve the three-axis torque model of the UAV according to the control input to obtain the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the UAV.

[0156] It should be noted that the control input needs to be calculated into motor speed ω and motor deflection angle θ using a mixer. First, assuming the motor deflection angle can be approximated as 0, the UAV's three-axis torque model can be simplified as follows:

[0157]

[0158] Then we have:

[0159]

[0160] Based on the already calculated resultant torque M on the UAV body, M can be solved using existing algorithms. P1 M P2 and M P3 Therefore, the rotational speed ω1 of the left rotor motor and the rotational speed ω2 of the right rotor motor of the UAV can be calculated.

[0161] Substituting ω1 and ω2 into the UAV's three-axis torque model:

[0162]

[0163] This allows us to obtain the deflection angle θ1 of the left rotor motor and the deflection angle θ2 of the right rotor motor of the drone.

[0164] Step 108: Perform attitude control on the drone based on the rotation speed and deflection angle of the two vector motors on the left and right sides of the top of the drone.

[0165] It should be noted that after solving for the rotational speed ω1 of the left rotor motor, the rotational speed ω2 of the right rotor motor, the deflection angle θ1 of the left rotor motor, and the deflection angle θ2 of the right rotor motor, the attitude of the dual-rotor drone system can be precisely controlled by the sliding mode controller.

[0166] To illustrate and demonstrate the effectiveness of the attitude control method for the amphibious dual-rotor UAV provided in this invention, please refer to [link / reference needed]. Figures 2-5 .Depend on Figure 2 It is evident that all three axes of the amphibious dual-rotor UAV can dynamically follow a sine wave, exhibiting fast response, no overshoot, no oscillation, and excellent performance. Figure 3 It is evident that the pitch angle of the amphibious dual-rotor UAV can dynamically follow a sine wave, exhibiting fast response, no overshoot, no oscillation, excellent performance, and extremely small steady-state error. Figure 4 It is evident that all three axes of this amphibious dual-rotor UAV can follow step waves, exhibiting fast response, no overshoot, no oscillation, and excellent performance. Figure 5 It is evident that the amphibious dual-rotor UAV can follow step waves, has a fast response, no overshoot, no oscillation, excellent performance, and extremely small steady-state error.

[0167] The attitude control method for an amphibious dual-rotor UAV provided by this invention solves for the control input of the UAV sliding mode controller by using the UAV's mechanical model, angular velocity model, and sliding mode controller's sliding surface mathematical model. By optimizing the control input, precise attitude control of the dual-rotor UAV system is achieved, enabling precise hovering, smooth take-off and landing, and good attitude control performance. It effectively addresses the uncertainties of the system model and time-varying environmental effects, improves the robustness and stability of the system in complex environments, and solves the technical problems of poor adaptability and low robustness of existing attitude control methods for amphibious dual-rotor UAVs under environmental changes.

[0168] For easier understanding, please refer to Figure 6 This invention provides an embodiment of an attitude control system for an amphibious dual-rotor unmanned aerial vehicle, comprising:

[0169] The coordinate system construction module is used to establish the ground coordinate system and the UAV body coordinate system;

[0170] The first modeling module is used to construct the three-axis torque model and the torque kinematics model of the UAV based on the ground coordinate system and the UAV body coordinate system.

[0171] The second modeling module is used to define the UAV body angular velocity model and the UAV body angular velocity error model;

[0172] The third modeling module is used to construct a dynamic model based on angular velocity error, based on the UAV torque kinematics model, the UAV body angular velocity model, and the UAV body angular velocity error model.

[0173] The fourth modeling module is used to construct the mathematical model of the sliding surface of the UAV sliding mode controller;

[0174] The first solution module is used to solve for the control input of the UAV sliding mode controller based on the dynamic model and the sliding surface mathematical model based on the angular velocity error.

[0175] The second solution module is used to solve the three-axis torque model of the UAV based on the control input, and obtain the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the UAV.

[0176] The attitude control module is used to control the attitude of the drone based on the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the drone.

[0177] The first solution module is specifically used for:

[0178] Differentiate the mathematical model of the sliding surface and configure the sliding surface reaching law of the UAV sliding surface controller;

[0179] By setting the derivative of the sliding surface mathematical model to 0 and the sliding surface reaching law to 0, and by combining the dynamic model based on the angular velocity error and the sliding surface mathematical model, the resultant torque on the UAV body is solved, and the control input of the UAV sliding mode controller is obtained.

[0180] The three-axis torque model of the UAV is as follows:

[0181]

[0182] Among them, M P1 Let M be the torque of the UAV in the x-axis direction of the UAV's body coordinate system. P2 Let M be the torque of the UAV in the y-axis direction of the UAV's body coordinate system. P3 Let be the torque of the UAV along the z-axis of the UAV's body coordinate system; d is the horizontal distance between the points of application of the lift forces of the two UAV rotors and the UAV's center of gravity; h is the vertical distance between the points of application of the lift forces of the two UAV rotors and the UAV's center of gravity; T1 is the lift provided by the left rotor of the UAV; T2 is the lift provided by the right rotor of the UAV; C m ω1 is the torque coefficient of the motor, ω2 is the rotational speed of the left rotor motor of the drone, θ1 is the deflection angle of the left rotor motor of the drone, and θ2 is the deflection angle of the right rotor motor of the drone.

[0183] The kinematic model of the UAV torque is as follows:

[0184]

[0185] Where J is the moment of inertia, M is the net torque acting on the UAV body, d is the disturbance torque, and Ω b Let be the angular velocity of the UAV in the UAV's body coordinate system. Differentiate the angular velocity of the UAV in the UAV's body coordinate system, k d This is the coefficient matrix of the resistance force encountered during rotation.

[0186] The angular velocity model of the drone body is as follows:

[0187] Ω c =α c arctan(α a E q )

[0188] α c =diag(α) c1 α c2 α c3 )

[0189] α a =diag(α) a1 α a2 α a3)

[0190] E q =2q e,0 q e,v

[0191] Among them, Ω c For the desired angular velocity of the organism, α c α is the first adjustable coefficient. c1 For α c x-axis component, α c2 For α c The y-axis component, α c3 For α c z-axis component, α a α is the second adjustable coefficient. a1 For α a x-axis component, α a2 For α a The y-axis component, α a3 For α a The z-axis component, E q Let q be the correlation coefficient. e,0 Let q be the real part of the attitude error. e,v This represents the imaginary part of the attitude error;

[0192] The UAV body angular velocity error model is as follows:

[0193] Ω e =Ω b -Ω c

[0194] Among them, Ω e This represents the expected angular velocity error of the machine body.

[0195] The dynamic model based on angular velocity error is as follows:

[0196]

[0197] in, Differentiate the desired angular velocity error of the organism.

[0198] The mathematical model of the sliding surface of the UAV sliding mode controller is as follows:

[0199]

[0200] E q =[a1 a2 a3] T α3=[l1 l2 l3] T

[0201] Where s is the sliding surface, α1, α2, and α3 are all three-dimensional column vectors, β0 is a coefficient greater than 1, γ(·) is the operation function, and a1, a2, and a3 are Eq The triaxial coefficients are l1, l2, and l3, which are the triaxial coefficients of α3.

[0202] The attitude control system of the amphibious dual-rotor UAV provided by the present invention is used to execute the attitude control method of the amphibious dual-rotor UAV provided by the present invention. Its principle and the technical effect achieved are the same as the attitude control method of the amphibious dual-rotor UAV provided by the present invention, and will not be repeated here.

[0203] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An attitude control method for an amphibious dual-rotor unmanned aerial vehicle, characterized in that, include: Establish a ground coordinate system and a UAV body coordinate system; Based on the ground coordinate system and the UAV body coordinate system, a three-axis torque model and a UAV torque kinematic model are constructed. Define the UAV body angular velocity model and the UAV body angular velocity error model; Based on the UAV torque kinematics model, UAV body angular velocity model, and UAV body angular velocity error model, a dynamic model based on angular velocity error is constructed. Construct a mathematical model of the sliding surface for a sliding mode controller for an unmanned aerial vehicle (UAV); Based on the dynamic model and sliding surface mathematical model based on angular velocity error, the control input of the UAV sliding mode controller is solved; The three-axis torque model of the UAV is solved based on the control input to obtain the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the UAV. The attitude control of the drone is performed based on the rotation speed and deflection angle of the two vector motors on the left and right sides of the top of the drone. The mathematical model of the sliding surface of the UAV sliding mode controller is as follows: ； ； Where s is the sliding surface. All are three-dimensional column vectors. A coefficient greater than 1 For operation functions, for The triaxial coefficients, for The triaxial coefficients, This represents the expected angular velocity error of the machine body.

2. The attitude control method for an amphibious dual-rotor UAV according to claim 1, characterized in that, The three-axis torque model of the UAV is as follows: ； in, Let be the torque of the UAV in the x-axis direction of the UAV's body coordinate system. Let be the torque of the UAV in the y-axis direction of the UAV's body coordinate system. Let be the torque of the UAV along the z-axis of the UAV's body coordinate system, d be the horizontal distance between the two rotor lift points and the UAV's center of gravity, and h be the vertical distance between the two rotor lift points and the UAV's center of gravity. The lift provided to the left rotor of the drone The lift provided to the right rotor of the drone This is the torque coefficient of the motor. This refers to the rotational speed of the left rotor motor of the drone. This refers to the rotational speed of the right rotor motor of the drone. This represents the deflection angle of the drone's left rotor motor. This refers to the deflection angle of the right rotor motor of the drone.

3. The attitude control method for an amphibious dual-rotor UAV according to claim 2, characterized in that, The kinematic model of the UAV torque is as follows: ； Where J is the moment of inertia, M is the net torque acting on the UAV body, and d is the disturbance torque. Let be the angular velocity of the UAV in the UAV's body coordinate system. Differentiate the angular velocity of the UAV in the UAV's body coordinate system. This is the coefficient matrix of the resistance force encountered during rotation.

4. The attitude control method for an amphibious dual-rotor UAV according to claim 3, characterized in that, The angular velocity model of the UAV body is as follows: ； ； in, For the desired angular velocity of the body, The first adjustable coefficient, for x-axis component, for The y-axis component, for z-axis component, This is the second adjustable coefficient. for x-axis component, for The y-axis component, for z-axis component, The correlation coefficient, Let be the real part of the attitude error. This represents the imaginary part of the attitude error; The UAV body angular velocity error model is as follows: ； in, This represents the expected angular velocity error of the machine body.

5. The attitude control method for an amphibious dual-rotor UAV according to claim 4, characterized in that, The dynamic model based on angular velocity error is as follows: ； in, Differentiate the desired angular velocity error of the organism.

6. The attitude control method for an amphibious dual-rotor unmanned aerial vehicle according to claim 1, characterized in that, Based on the dynamic model and sliding surface mathematical model based on angular velocity error, the control input of the UAV sliding mode controller is solved, including: Differentiate the mathematical model of the sliding surface and configure the sliding surface reaching law of the UAV sliding surface controller; By setting the derivative of the sliding surface mathematical model to 0 and the sliding surface reaching law to 0, and by combining the dynamic model based on the angular velocity error and the sliding surface mathematical model, the resultant torque on the UAV body is solved, and the control input of the UAV sliding mode controller is obtained.

7. An attitude control system for an amphibious dual-rotor unmanned aerial vehicle, characterized in that, include: The coordinate system construction module is used to establish the ground coordinate system and the UAV body coordinate system; The first modeling module is used to construct the three-axis torque model and the torque kinematics model of the UAV based on the ground coordinate system and the UAV body coordinate system. The second modeling module is used to define the UAV body angular velocity model and the UAV body angular velocity error model; The third modeling module is used to construct a dynamic model based on angular velocity error, based on the UAV torque kinematics model, the UAV body angular velocity model, and the UAV body angular velocity error model. The fourth modeling module is used to construct the mathematical model of the sliding surface of the UAV sliding mode controller; The first solution module is used to solve for the control input of the UAV sliding mode controller based on the dynamic model and the sliding surface mathematical model based on the angular velocity error. The second solution module is used to solve the three-axis torque model of the UAV based on the control input, and obtain the rotational speed and deflection angle of the two vector motors on the left and right sides of the top of the UAV. The attitude control module is used to control the attitude of the drone based on the rotation speed and deflection angle of the two vector motors on the left and right sides of the top of the drone. The mathematical model of the sliding surface of the UAV sliding mode controller is as follows: ； ； Where s is the sliding surface. All are three-dimensional column vectors. A coefficient greater than 1 For operation functions, for The triaxial coefficients, for The triaxial coefficients, This represents the expected angular velocity error of the machine body.

8. The attitude control system of the amphibious dual-rotor UAV according to claim 7, characterized in that, The first solution module is specifically used for: Differentiate the mathematical model of the sliding surface and configure the sliding surface reaching law of the UAV sliding surface controller; By setting the derivative of the sliding surface mathematical model to 0 and the sliding surface reaching law to 0, and by combining the dynamic model based on the angular velocity error and the sliding surface mathematical model, the resultant torque on the UAV body is solved, and the control input of the UAV sliding mode controller is obtained.

9. The attitude control system of the amphibious dual-rotor UAV according to claim 7, characterized in that, The three-axis torque model of the UAV is as follows: ； in, Let be the torque of the UAV in the x-axis direction of the UAV's body coordinate system. Let be the torque of the UAV in the y-axis direction of the UAV's body coordinate system. Let be the torque of the UAV along the z-axis of the UAV's body coordinate system, d be the horizontal distance between the two rotor lift points and the UAV's center of gravity, and h be the vertical distance between the two rotor lift points and the UAV's center of gravity. The lift provided to the left rotor of the drone The lift provided to the right rotor of the drone This is the torque coefficient of the motor. This refers to the rotational speed of the left rotor motor of the drone. This refers to the rotational speed of the right rotor motor of the drone. This represents the deflection angle of the drone's left rotor motor. This refers to the deflection angle of the right rotor motor of the drone.

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