Integrated control method for coupled motion of a multibody system of an aircraft and its components

Abstract

The application provides a method for integrated control of multi-body coupled motion of an aircraft and components thereof, which comprises: establishing a full-state dynamic model of the multi-body coupled motion aircraft, and deriving a scalar differential equation capable of explicitly showing a control input and a controlled variable; designing a basic control structure of feedback linearization without considering modeling errors, parameter errors and external disturbances; designing a control structure considering external disturbances and modeling errors, and designing a model compensation extended state observer to online estimate the external disturbances and the modeling errors, and then compensating the output of the control structure to ensure the closed-loop control effect, and finally generating the control structure compensated for the external disturbances and the modeling errors. The method can solve the problems of control structure design difficulty and poor control effect of the dynamic model of the multi-body coupled motion aircraft, and achieve the purpose of high-precision and strong-robust integrated control of the aircraft components and attitude.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aircraft control technology, and relates to an integrated control method for multi-body coupled motion of an aircraft and components thereof. BACKGROUND

[0002] With the continuous development of aerospace technology, aircraft need to meet more and more diversified task requirements. Multi-body coupled motion aircraft can control the state of each component of the body through its own multi-actuator to achieve higher maneuverability and flexibility, adapt to more complex flight environments, and have high potential application value in military and civilian fields. Unlike traditional aircraft six-degree-of-freedom dynamics modeling, the dynamics model of multi-body coupled motion aircraft increases several degrees of freedom due to the presence of movable components, showing multi-body, multi-degree-of-freedom and strong nonlinearity. The aerodynamic force / torque, pressure center, mass center and moment of inertia of the multi-body coupled motion aircraft change greatly with the change of component state, the complexity of the dynamics model increases dramatically, and the traditional control design method and theory based on small perturbation assumption are no longer applicable, bringing great challenges to the design of aircraft component and attitude control law.

[0003] Although domestic and foreign scholars have carried out certain research on the control of multi-body coupled motion aircraft, there are still problems such as poor control effect and complex control law that is difficult to apply in engineering. Multi-body coupled motion aircraft is a typical strong nonlinear system. Due to its multi-degree-of-freedom strong coupling and strong time-varying characteristics, the traditional PID error control method which does not depend on the model has problems such as parameter tuning difficulty and poor control effect, and the industry generally uses nonlinear control methods such as backstepping control and sliding mode control which depend on prior model information to achieve better control effect. However, considering the modeling error of the real system and external disturbances, the control method which depends on model information generally has problems such as weak robustness and difficulty in engineering application.

[0004] If the dynamics model of multi-body coupled motion aircraft is established by imitating the description framework of traditional flight mechanics, the derivation process and representation form will be quite complex, and the coupling effect of component actuation on the attitude of the aircraft body cannot be accurately described. Although the multi-body coupled motion aircraft dynamics equation established based on virtual power principle has a simple representation form, it is in the form of a high-dimensional vector differential equation with multiple degrees of freedom. The control input and controlled state quantity are implicitly in the high-dimensional matrix, and the relationship between the key controlled quantities such as the attitude of the aircraft and the state of the components and the control input such as the rudder and the actuator is not clear. At the same time, it does not conform to the usage habits of traditional flight mechanics, and it is difficult for designers to directly complete the control structure design for the controlled quantities.

[0005] Due to the complex coupling influence between the multi-body coupled motion aircraft components and the body, no matter which control method is selected to carry out the control loop design, two prominent problems will always be faced: one is that even if the scalar dynamics equation containing only the component, attitude and other controlled states and the control input, actuator, rudder and other controlled inputs is obtained, the coupling influence between the component actuation and the attitude is still serious, and it is difficult to achieve the decoupling control of the three channels by referring to the traditional aircraft design idea, and the coupling influence must be considered in the control structure design as prior information; the second is that most nonlinear control methods rely on the prior model information of the aircraft, but the aircraft faces complex flight environment, and the real physical process must exist external disturbance and modeling error, and the robustness of the model-dependent control method is difficult to guarantee.

[0006] Therefore, it is urgent to study the control design method of the multi-body coupled motion aircraft, design the nonlinear control structure based on the built refined dynamics model, and further introduce the observer to compensate the external disturbance and modeling error, so as to provide a new technical approach for solving the control problem of the multi-body coupled motion aircraft and improving the robustness of the closed-loop control system. SUMMARY

[0007] The purpose of the present application is to at least solve one of the problems existing in the prior art.

[0008] To this end, the present application provides an integrated control method for the multi-body coupled motion of an aircraft and its components, which is closely related to engineering practice and can solve the problems of difficult control structure design and poor control effect caused by the overly complex dynamics model of the multi-body coupled motion aircraft, so as to achieve the purpose of high-precision and strong-robust integrated control of the aircraft components and attitude.

[0009] The technical solution of the present application is:

[0010] An integrated control method for the multi-body coupled motion of an aircraft and its components, the steps of the method are as follows:

[0011] Step 1: According to the real physical characteristics of the actuating components and the execution mechanism of the aircraft and the geometric position relationship relative to the aircraft body, a full-state dynamics model of the multi-body coupled motion aircraft is established based on the virtual power principle;

[0012] Step 2: According to the control requirements, the description variables related to the component actuation and the attitude change in the full-state dynamics model are extracted as the controlled variables, and the scalar differential equation capable of containing the control input and the controlled variable is derived;

[0013] Step 3: Based on the scalar differential equation containing the control input and the controlled variable, without considering the modeling error, parameter error and external disturbance, a basic control structure of feedback linearization is designed to realize the decoupling control of the controlled variable;

[0014] Step four, on the basis of the control structure of step three, a control structure considering external disturbance and modeling error is designed, and a model compensation extended state observer is designed to estimate the external disturbance and modeling error on line, and then compensate the output of the control structure of this step, which plays a role of restoring the real system of the aircraft to the nominal system of the aircraft established according to the prior model information of the aircraft, and ensures the closed-loop control effect, and finally generates the control structure compensated for the external disturbance and modeling error.

[0015] Further, the aircraft has two kinds of actuators: one is a sliding actuator, which controls the linear motion of the actuating part A along the axis with a displacement s; and the other is two rotating actuators, which respectively control the rotation of the actuating part B1 and the actuating part B2 around the respective rudder axes.

[0016] The multi-body coupled motion is the coupling of the motion of the aircraft, the linear motion of the actuating part A, and the rotation of the actuating part B1 and the actuating part B2.

[0017] Further, in step one, the full-state dynamic model of the multi-body coupled motion aircraft is established based on the virtual power principle, which is that the virtual power of the translational inertia force plus the virtual power of the rotational inertia force is equal to the virtual power of the external force, and the specific expression is shown as formula (1):

[0018]

[0019] In the formula, r c,i is the centroid vector of the rigid body, ω i is the angular velocity vector of the rigid body, F a,i is the external force acting on the rigid body, M a,i is the external torque acting on the rigid body, m i is the mass of the rigid body, J i is the moment of inertia, and g is the gravity acceleration vector. ω i is the measured value of the angular velocity vector of the rigid body.

[0020] Further, in step two, the scalar differential equation capable of explicitly containing the control input and the controlled variable is derived as:

[0021] The fuselage is selected as the main rigid body, the actuator part is selected as the slave rigid body, and the description variable q is selected as the controlled variable, which includes the fuselage centroid coordinates x and y, the fuselage pitch angle θ, the displacement s of part A, and the rotation angle χ of part B1. The control input is selected according to the description variable q, which includes the body axial control force Δf x , the body normal control force Δf y , the body elevator deflection δ z , the part A control force F s , and the part B1 control torque M w .

[0022] According to the controlled quantity and the control input, the control input is contained in the scalar differential equation through the decomposition of the aerodynamic force and the aerodynamic moment, and a scalar differential equation for the control loop design is obtained as shown in equation (2):

[0023]

[0024] In the formula, M is the mass matrix, q is the state variable, q is the first order differential of the state variable, q is the second order differential of the state variable, and is the derivative of the pitch moment to the rudder deflection, and is a known quantity,

[0025] is the mass matrix coefficient, and is the force matrix coefficient.

[0026] Further, in step three, without considering the modeling error, the parameter error and the external disturbance, the feedback linearization basic control structure designed is:

[0027] The scalar differential equation of equation (2) can be further rewritten in the form shown in equation (15):

[0028]

[0029] In the formula, M is the mass matrix, q is the state variable, q is the first order differential of the state variable, q is the second order differential of the state variable, and

[0030]

[0031] Thereafter, based on the idea of feedback linearization, nonlinear compensation is introduced, which converts the complex control of the multi-body coupled motion aircraft into simple linear control, realizes the decoupling control of each controlled quantity, and introduces the control quantity u, and the dynamics system of the multi-body coupled motion aircraft is represented in the form shown in equation (18):

[0032] Mu+F=T F τ (6)

[0033] By combining equation (15) and equation (18), because M is a symmetric positive definite matrix and is reversible, the nonlinear term is eliminated, and then a decoupled linear constant system is obtained:

[0034]

[0035] Based on this, the PD control convenient for engineering application is introduced to construct an ideal closed-loop control system:

[0036]

[0037] In the formula, M is the mass matrix, q is the state variable, q is the first order differential of the state variable, q is the second order differential of the state variable, and and e=(q-q d ) are the differential of the state variable and the error of the state variable, q d 、 is the state variable, the differential of the state variable, the second order differential of the state variable, and k dis the differential gain matrix, k p is the proportional gain matrix, the model control algorithm based on feedback linearization is:

[0038]

[0039] Therefore, formula (21) is the basic control structure of feedback linearization without considering external disturbance and modeling error.

[0040] Further, formula (21) is brought into formula (18), and the error equation of the closed-loop control system is:

[0041]

[0042] By changing k d , k p The poles corresponding to any controlled variable are configured to the specified position, the desired dynamic characteristics are obtained, and the tracking error of the closed-loop control system to the command is ensured to converge to 0 gradually.

[0043] Further, in step four, the control structure considering external disturbance and modeling error is designed as:

[0044] Under the condition of considering external disturbance and modeling error, the longitudinal channel dynamics equation of the multibody coupled motion aircraft is:

[0045]

[0046] In the formula, M0, F0 represent the model prior information used for the dynamics modeling of the multibody coupled motion aircraft, ΔM, ΔF represent the modeling error, τ d represents external disturbance;

[0047] At this time, the model control algorithm based on the feedback linearization idea is:

[0048]

[0049] Therefore, formula (24) is the control structure of feedback linearization considering external disturbance and modeling error;

[0050] Substituting formula (24) into formula (18) can obtain the error equation of the closed-loop control system:

[0051]

[0052] Let d is the total disturbance containing the modeling error and the external disturbance;

[0053] Therefore, the longitudinal channel dynamics equation of the multibody coupled motion aircraft described by formula (23) under the condition of considering the total disturbance can be further written as follows:

[0054]

[0055] Further, in the fourth step, the design model compensates the expansion state observer as:

[0056] Let And assuming d is continuously differentiable, x2 can be used as a new expansion state, and the multi-body coupled motion aircraft dynamics system can be expanded into the following state space form:

[0057]

[0058] Therefore, the expansion state observer for model compensation can be written as follows:

[0059]

[0060] In the formula, z1 is the estimated value of the description variable q, z2 is the estimated value of the model total disturbance d, λ i > 0 represents the basic frequency point when the i-th state is disturbed; ξ i > 0 represents the frequency conversion factor when the i-th state is disturbed; μ i > 0 represents the error switching factor when the i-th state is disturbed, and

[0061] Further, in the fourth step, the control structure after compensating the external disturbance and the modeling error is:

[0062]

[0063] Therefore, formula (29) is the control structure considering and compensating the external disturbance and the modeling error.

[0064] By applying the above technical solution, the application has the following beneficial effects:

[0065] (1) The application proposes an integrated control method for the multi-body coupled motion of an aircraft and its components, specifically relates to a multi-body coupled motion aircraft dynamics model established based on the virtual power principle, and a control law design method for realizing integrated robust control of aircraft components and attitude; the application is aimed at the scalar differential equation of the controlled state of the multi-body coupled motion aircraft established based on the virtual power principle, and realizes decoupling control of the controlled state through feedback linearization, can better cope with the adverse effects of the multi-body nonlinear coupled motion of the aircraft and its components on the attitude of the aircraft, and achieves integrated control of the aircraft and its components, and can be used to guide the integrated control design of components and attitude of the multi-body coupled motion aircraft.

[0066] (2) Based on the basic design idea of the frequency point adaptive switching extended state observer, a frequency point adaptive model compensation extended state observer is proposed. The state equation of the observer is established on the basis of prior model information, and the modeling error and external disturbance outside the prior model information of the multi-body coupled motion aircraft can be estimated online. After compensation, the real system of the aircraft can always be consistent with the nominal system of the aircraft used to design the feedback linearization control law. The introduction of prior model information reduces the difficulty of disturbance estimation of the observer, improves the robustness of the closed-loop control system while ensuring tracking accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0067] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is readily apparent to one skilled in the art that the accompanying drawings, described below, are merely some embodiments of the application and that other drawings can be obtained from these drawings without creative labor.

[0068] Figure 1 A schematic diagram of a multi-body coupled motion aircraft is given;

[0069] Figure 2 A unified control structure diagram for the multi-body coupled motion of the aircraft and its components is given;

[0070] Figure 3 A unified control pitch angle control response diagram for the multi-body coupled motion of the aircraft and its components is given;

[0071] Figure 4 A unified control component A control response diagram for the multi-body coupled motion of the aircraft and its components is given;

[0072] Figure 5 A unified control component B1 control response diagram for the multi-body coupled motion of the aircraft and its components is given;

[0073] Figure 6 A unified control pitch angle velocity disturbance observation diagram for the multi-body coupled motion of the aircraft and its components is given. DETAILED DESCRIPTION

[0074] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other in the case of no conflict. The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The description of the at least one example embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0075] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or combinations thereof.

[0076] Unless specifically stated otherwise, the relative arrangement of components and steps, numerical expressions, and numerical values set forth in the various embodiments described herein are not limiting. It should be understood that the various parts shown in the drawings are not necessarily drawn to scale in proportion. The techniques, methods and devices known to those skilled in the relevant art can not be discussed in detail, but should be considered as part of the authorized description. In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, so that once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0077] Embodiment 1:

[0078] The present embodiment provides a method for integrated control of multi-body coupled motion of an aircraft and its components, the steps of which are as follows:

[0079] Step 1: According to the real physical characteristics of the actuating components and actuators of the aircraft and the geometric position relationship relative to the aircraft body, a full-state dynamic model of the multi-body coupled motion aircraft is established based on the virtual power principle;

[0080] Step two, according to the control requirements, the state variables (i.e. description variables) related to the actuation of components and the changes of attitude in the full state dynamic model are extracted as controlled variables, and scalar differential equations which can explicitly show the control input and the controlled variables are derived to facilitate the design of the basic control structure;

[0081] Step three, based on the scalar differential equations which can explicitly show the control input and the controlled variables, the basic control structure of feedback linearization is designed without considering the modeling errors and external uncertainties, the decoupling control of the controlled variables is realized, and the fast and accurate tracking of the instructions by the controlled variables under ideal conditions without external disturbances is ensured;

[0082] Step four, on the basis of the basic control structure in step three, the control structure considering external disturbances and modeling errors is designed, and the model compensation extended state observer is designed to estimate the external disturbances and modeling errors online, and then the output of the control structure in this step is compensated, which plays a role in restoring the real system of the aircraft to the nominal system of the aircraft established according to the prior model information of the aircraft, ensuring the closed-loop control effect, and finally generating the control structure compensated for external disturbances and modeling errors.

[0083] Embodiment 2:

[0084] This embodiment is based on embodiment 1, and gives a specific example of an integrated control method for the multi-body coupled motion of an aircraft and its components:

[0085] Referring to the accompanying drawings Figure 1 The aircraft mainly has two kinds of actuators: one is a sliding actuator, which controls the linear motion of the actuation component A along the axis with a displacement s; the other is two rotating actuators, which respectively control the rotation of the actuation component B1 and the actuation component B2 around the respective rudder axes of the fuselage;

[0086] The multi-body coupled motion is the coupling of the motion of the aircraft, the linear motion of the actuation component A, and the rotation of the actuation component B1 and the actuation component B2.

[0087] Step one, based on the virtual power principle, a full state dynamic model of the multi-body coupled motion aircraft is established:

[0088] The virtual power principle is the physical basis for establishing the dynamic model of the multi-body coupled motion aircraft. For any multi-body coupled motion aircraft dynamic system, the virtual power principle can be expressed as: the virtual power of the translational inertia force plus the virtual power of the rotational inertia force is equal to the virtual power of the external force, which is shown in formula (1):

[0089]

[0090] In the formula, r c,i ,ω iFor the radius vector and angular velocity vector of the rigid body's center of mass; F a,i M a,i m represents the external forces and torques acting on a rigid body. i J is the mass of a rigid body; i g is the moment of inertia; g is the gravitational acceleration vector. This is the measured value of the rigid body's angular velocity vector;

[0091] Equation (1) is the full-state dynamic model of a multi-body coupled motion aircraft.

[0092] Step two: Extract the state variables (i.e., descriptive variables) related to component actuation and attitude change from the full-state dynamic model as controlled variables, and derive the scalar differential equations that explicitly contain the control input and controlled variables:

[0093] Based on the relative motion between the fuselage and actuators, and between the actuator components, of a multi-body coupled motion aircraft, the fuselage is selected as the principal rigid body and the actuator components as the subordinate rigid bodies. Therefore, a descriptive variable q is selected as the controlled variable. The descriptive variable q includes: fuselage center of mass coordinates x and y, fuselage pitch angle θ, component A displacement s, and component B1 rotation angle χ. Based on the descriptive variable q, control inputs are selected, including: the fuselage axial control force Δf. x Normal control force Δf of the body y δ deflection of the elevator z Component A control force F s Component B1 control torque M w ;

[0094] Based on the controlled variable and the control input, the control input is explicitly contained in the scalar differential equation through the decomposition of aerodynamic force and aerodynamic torque, and the scalar differential equation for the control loop design is obtained as shown in equation (2):

[0095]

[0096] In the formula, Let be the derivative of the pitching moment with respect to the rudder deflection, and be a known quantity.

[0097] The mass matrix coefficients are as follows:

[0098]

[0099] M 13 =M 31 = -n1 cosθ - n2sinθ, M 14 =M 41 = -m2cosθ, M 15 =M 51 =2m1(x w sinχ+zw cosχ)cosθ

[0100] (21)M 23 = M 32 = -n1 sinθ + n2 cosθ, M 24 = M 42 = -m2 sinθ, M 25 = M 52 = 2m1(x w sinχ+z w cosχ)sinθ (22)

[0102] M 34 = M 43 = m2y s , M 35 = M 53 = 2m1(y w -y b )(z w cosχ+x w sinχ) (23)

[0103] n1= m2y s + 2m1(y b -y w ), n2= 2m1(x b -x w cosχ+z w sinχ) + m2(x s -s) (24)

[0104]

[0105] are force array coefficients, specifically:

[0106]

[0107]

[0108] wherein P is the thrust of the aircraft, in equations (3) to (14), the parameters appearing are defined as shown in Table 1, wherein the body system and the vehicle system base vector directions are consistent:

[0109] Table 1 Parameter definition table of multi-body coupled motion aircraft dynamics model

[0110]

[0111]

[0112] As can be seen from the above formula (2)-(14), the mass matrix coefficients and force matrix coefficients of the multi-body coupled motion aircraft are no longer constant matrices, but functions of state variables, which change with time. There are many description variables in the force matrix, and the strong nonlinearities and multi-degree of freedom coupled unsteady effects between the aircraft attitude and the actuator motion can be fully considered.

[0113] Step three, based on the scalar differential equation of the control input and the controlled variable, the feedback linearization basic control structure is designed without considering modeling errors, parameter errors and external disturbances:

[0114] Without considering modeling errors, parameter errors and external disturbances, the scalar differential equation of formula (2) can be further rewritten in the form shown in formula (15):

[0115]

[0116] In the formula:

[0117]

[0118] Thereafter, based on the idea of feedback linearization, nonlinear compensation is introduced, which converts the complex control of the multi-body coupled motion aircraft into relatively simple linear control, realizes the decoupling control of each controlled variable, and introduces the control variable u. The dynamics system of the multi-body coupled motion aircraft can be expressed in the form shown in formula (18):

[0119] Mu+F=T F τ (35)

[0120] By combining formula (15) and formula (18), and because M is a symmetric positive definite matrix and reversible, if the nonlinear term is eliminated, a decoupled linear constant system can be obtained:

[0121]

[0122] Based on this, the PD control convenient for engineering application is introduced to construct an ideal closed-loop control system:

[0123]

[0124] In the formula and e=(q-q d ) are the differential of the state variable and the error of the state variable, q d , are the state variable, the differential of the state variable, the second differential of the state variable, and the instruction k d is the differential gain matrix, and k p is the proportional gain matrix. The model control algorithm based on feedback linearization is:

[0125]

[0126] Therefore, formula (21) is the basic control structure of feedback linearization without considering external disturbance and modeling error.

[0127] Further, formula (21) is brought into formula (18), and the error equation of the closed-loop control system is obtained as:

[0128]

[0129] In the ideal state, k d , k p The poles corresponding to any controlled quantity (i.e., the eigenvalues of the state quantity error e obtained by formula (22)) are configured to the specified position to obtain the desired dynamic characteristics, and the tracking error of the closed-loop control system to the command is gradually convergent to 0, ensuring that the controlled quantity can track the command quickly and accurately under the ideal condition without external disturbance.

[0130] Step four, design a model compensation extended state observer to improve the robustness of the closed-loop control system:

[0131] In the real situation, the aircraft must exist external disturbance and modeling error, and the longitudinal channel dynamics equation of the multi-body coupled motion aircraft can be written in the following general form:

[0132]

[0133] In the formula, M0, F0 represent the model prior information used for the dynamics modeling of the multi-body coupled motion aircraft, ΔM, ΔF represent two error terms in the modeling error, τ d represents external disturbance;

[0134] At this time, the model control algorithm based on the feedback linearization idea is:

[0135]

[0136] Therefore, formula (24) is the feedback linearization control structure considering external disturbance and modeling error.

[0137] Further, formula (24) is brought into formula (18), and the error equation of the closed-loop control system is obtained as:

[0138]

[0139] Let d is the total disturbance containing external disturbance and modeling error. It is known that the basic control loop based on feedback linearization of formula (24) only compensates for the known nonlinear part, and external disturbance and modeling error will inevitably lead to the decline of the tracking performance of the closed-loop control system, and will make the control unstable in severe cases.

[0140] Therefore, the longitudinal channel dynamics equation of the multi-body coupled motion aircraft described by equation (23) can be further written as follows under the condition of considering external disturbances and modeling errors:

[0141]

[0142] In order to improve the robustness of the closed-loop control system, the external disturbance and modeling error are considered to be compensated, so that the inner loop based on the feedback linearization control algorithm remains consistent with the prior model, and the closed-loop tracking performance is guaranteed. In order to achieve the purpose of model compensation, the disturbance observer design idea commonly used in engineering is selected, the total disturbance d is observed and compensated in real time.

[0143] Considering that the derivative term of the state quantity can be measured by the sensor, let and assuming that d is continuously differentiable, x2 can be used as a new extended state, and the dynamics system of the multi-body coupled motion aircraft can be expanded to the following state space form:

[0144]

[0145] The frequency point adaptive switching extended state observer shown in equation (28) is designed for equation (27) to estimate the total disturbance d online, and the real aircraft system is restored to the nominal aircraft system established based on the prior model information through compensation, ensuring the effect of the basic control loop. The extended state observer for model compensation can be written as follows:

[0146]

[0147] In equation (28), z1 is the estimated value of the description variable q, z2 is the estimated value of the total disturbance d, λ i > 0 represents the basic frequency point when the i-th state is disturbed; ξ i > 0 represents the frequency conversion factor when the i-th state is disturbed; μ i > 0 represents the error switching factor when the i-th state is disturbed, and

[0148] The multi-body coupled motion aircraft component and attitude control algorithm after introducing the extended state observer for model compensation is shown in equation (29), and the closed-loop control loop structure is shown in Figure 2 :

[0149]

[0150] Therefore, equation (29) is the control structure considering external disturbances and modeling errors, and compensating for external disturbances and modeling errors.

[0151] After the closed-loop control structure design is completed according to the above steps, the effectiveness simulation analysis of the control method is carried out under ideal conditions and conditions of adding various uncertainties and disturbances, and results are shown in Figures 3-6 The simulation results show that the integrated control method for the multi-body coupling motion of the aircraft / component proposed in the embodiment overcomes the strong nonlinear and complex influence of component actuation on the aircraft attitude, can realize accurate and rapid tracking of the attitude angle command and the component actuation command, the command tracking adjustment time is relatively fast and basically has no steady-state error under ideal conditions, and good control effect can still be ensured under the condition of considering various uncertainties, has strong robustness, and the effectiveness of the proposed control method is verified.

[0152] For the sake of description, spatial relative terms such as "above", "upper", "top", "bottom", and the like can be used herein for ease of description to describe one device or feature's spatial position relation to another device or feature as illustrated in the drawings. It is to be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if a device in the drawings is turned over, a device described as "above" or "above" other devices or structures would then be oriented "below" or "below" other devices or structures. Accordingly, the illustrative term "above" can include both the "above" and "below" orientations. The device can also be oriented in other different ways (rotated 90 degrees or at other orientations) and the spatial relative descriptions used herein interpreted accordingly.

[0153] In addition, it should be noted that the use of "first", "second", and the like words to limit parts, only for the convenience of the corresponding parts to distinguish, such as no other declaration, the above words have no special meaning, therefore can not be understood as limiting the scope of the present application.

[0154] The above is only the preferred embodiment of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of integrated control of coupled motion of a multi-body of an aircraft and its components, characterized by, The steps of the method are as follows: Step one, based on the real physical characteristics of the actuator components and the actuator components and the geometric position relationship relative to the aircraft body, a full-state dynamic model of the multi-body coupled motion aircraft is established based on the virtual power principle; Step two, according to the control requirements, the description variables related to component actuation and attitude change in the full-state dynamic model are extracted as controlled variables, and a scalar differential equation capable of explicitly containing control input and controlled variables is derived; Step three, based on the scalar differential equation capable of explicitly containing control input and controlled variables, without considering modeling errors, parameter errors and external disturbances, a feedback linearization basic control structure is designed to realize decoupling control of the controlled variables; Step four, on the basis of the basic control structure of step three, a control structure considering external disturbances and modeling errors is designed, and a model compensation extended state observer is designed to estimate external disturbances and modeling errors online, and then the output of the control structure of this step is compensated, which plays a role in restoring the real system of the aircraft to the nominal system of the aircraft established according to the prior model information of the aircraft, ensuring the closed-loop control effect, and finally generating a control structure for compensating external disturbances and modeling errors; In step four, the control structure considering external disturbances and modeling errors is: Under the condition of considering external disturbances and modeling errors, the longitudinal channel dynamics equation of the multi-body coupled motion aircraft is: where M0, F0 represent model prior information for the dynamics modeling of a multibody coupled motion aircraft, ΔM, ΔF represent two error terms in the modeling error, τ d represents external disturbances; q is a description variable; is a second order differential of q, is a derivative of the pitching moment with respect to the rudder deflection, is a fuselage pitch angle; At this time, the model control algorithm based on the feedback linearization idea is: where q d , is a state quantity, a state quantity differential, a state quantity second-order differential command, k d is a differential gain matrix, k p is a proportional gain matrix; Therefore, formula (24) is the feedback linearization control structure considering external disturbances and modeling errors; Substitute equation (24) into Mu+F=T F τ, M is the mass matrix coefficient, F is the force matrix coefficient, control variable The closed-loop control system error equation is obtained as wherein and e = (q - q d ) is the state quantity differential and the state quantity error, is the second order differential of the state quantity; Let d is the total disturbance including modeling errors and external disturbances; Therefore, the longitudinal channel dynamics equation of the multi-body coupled motion aircraft described by formula (23) can be further written as follows under the condition of considering total disturbances: The design of the model compensation extended state observer is: Let And assuming d is continuously differentiable, x2 can be a new extended state, and the multi-body coupled motion aircraft dynamics system can be extended to the following state space form: Therefore, the extended state observer for model compensation can be written as follows: where z1 is an estimate of the variable q, z2 is an estimate of the total disturbance d, λ i > 0 is the base frequency for the i-th state when the disturbance is observed; ξ i > 0 is the frequency variation factor for the i-th state when the disturbance is observed; μ i > 0 is the error switching factor for the i-th state when the disturbance is observed, and The control structure after compensating external disturbances and modeling errors is: Therefore, formula (29) is the control structure considering external disturbances and modeling errors and compensating them.

2. A method of integrated control of coupled motions of a multi-body aircraft and its components as in claim 1, wherein, The aircraft has two types of actuators: one is a sliding actuator that controls the linear motion of actuator component A along the axis with displacement s; the other is two rotating actuators that control the rotation of actuator component B1 and actuator component B2 around their respective rudder axes. The multi-body coupled motion is the coupling of the motion of the aircraft, the linear motion of the actuator component A, and the rotational motion of the actuator component B1 and the actuator component B2.

3. A method of integrated control of coupled motions of a multi-body aircraft and its components as in claim 2, wherein, In step one, the full-state dynamic model of the multi-body coupled motion aircraft is established based on the virtual power principle as follows: the virtual power of the translational inertia force and the virtual power of the rotational inertia force are added to the virtual power of the external force, and the specific expression is shown in formula (1): where δ is the differential symbol, r c,i is the position vector of the center of mass of the rigid body, ω i is the angular velocity vector of the rigid body; F a,i , M a,i are the external force and external moment applied to the rigid body; m i is the mass of the rigid body; J i is the moment of inertia; g is the gravity acceleration vector; ω i is the measured value of the angular velocity vector of the rigid body.

4. A method of integrated control of coupled motions of a multi-body aircraft and its components as recited in claim 3, wherein, In step two, the scalar differential equation capable of explicitly containing control input and controlled variables is derived as follows: The fuselage is selected as a main rigid body, the actuator component is selected as a slave rigid body, a description variable q is selected as a controlled variable, and the description variable q includes: fuselage centroid coordinates x, coordinate y, and fuselage pitch angle Component A displacement s, component B1 rotation angle χ; a control input is selected according to the description variable q, and the control input includes: fuselage axial control force Δf x , fuselage normal control force Δf y , fuselage elevator deflection δ z , component A control force F s , component B1 control moment M w ; According to the controlled variables and control input, the control input is explicitly contained in the scalar differential equation through the decomposition of aerodynamic force and aerodynamic moment, and the scalar differential equation used for control loop design is shown in formula (2): wherein is the pitch moment derivative with respect to rudder deflection, which is a known quantity, is the mass matrix coefficient, is the force matrix coefficient, Δy c is the normal displacement error, i.e., normal position control command minus current normal position, -Δx c is the axial displacement error, i.e., axial position control command minus current axial position.

5. A method of integrated control of coupled motions of a multi-body aircraft and its components as recited in claim 4, wherein, In step three, without considering modeling errors, parameter errors and external disturbances, the feedback linearization basic control structure is designed as follows: The scalar differential equation of formula (2) can be further rewritten in the form shown in formula (15): In the formula: Thereafter, based on the idea of feedback linearization, nonlinear compensation is introduced to convert the complex control of the multi-body coupled motion aircraft into simple linear control, realize the decoupling control of each controlled variable, and introduce the control variable u. The dynamics system of the multi-body coupled motion aircraft is represented in the form shown in formula (18): Mu + F = T F τ (18) Integrating formula (15) and formula (18), because M is a symmetric positive definite matrix and is reversible, the nonlinear term is eliminated, and a decoupled linear constant system is obtained: Based on this, the PD control convenient for engineering application is introduced to construct an ideal closed-loop control system: wherein and e = (q - q d ) is the state variable differential and state variable error, q d , is the state variable, state variable differential, state variable second order differential command, k d is the differential gain matrix, k p is the proportional gain matrix, the model control algorithm based on feedback linearization is: Therefore, formula (21) is the basic control structure of feedback linearization without considering external disturbance and modeling error.

6. A method of integrated control of coupled motions of a multi-body aircraft and its components as in claim 5, wherein, Substituting formula (21) into formula (18), the error equation of the closed-loop control system is obtained as follows: By changing k d , k p Any controlled quantity corresponding to the pole configuration to the specified location, get the desired dynamic characteristics, and ensure that the closed-loop control system to the command tracking error converges to 0.

Images