A disturbance rejection control method for longitudinal models of ground effect vehicles within the ground effect zone.

Abstract

This invention discloses a disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone. First, a tracking differentiator is used to arrange the transition process between the desired input and the actual output of the system, minimizing the initial value deviation. Second, a new nonlinear function is introduced to improve the extended observer, greatly enhancing the system's disturbance rejection capability and robustness. Finally, by introducing a new nonlinear function, the nonlinear feedback law is improved to obtain the system control law, which greatly improves the system's control accuracy.

Description

Technical Field

[0001] This invention belongs to the field of aviation control technology, and in particular relates to a disturbance rejection control method for a longitudinal model of a ground effect vehicle in the ground effect zone. Background Technology

[0002] Ground effect vehicles (GEVs) are special aircraft that utilize the ground effect to achieve ultra-low-altitude, high-speed flight. Scholars both domestically and internationally have conducted research on them, and some universities and research institutions are actively developing GEVs. For example, the Measurement and Control Technology and Inertial Navigation Department of the School of Automation at Harbin Engineering University completed the design and fabrication of a prototype in 2010 and conducted related experiments using a GEV as a research platform. These experiments mainly included mathematical modeling and simulation of the GEV, design of navigation system hardware and software, data fusion algorithms, and design of the flight control system. In general, my country has developed GEV design technology with independent intellectual property rights and has successively developed several small GEVs. However, in terms of the development of GEV flight control technology, it still relies on traditional PID control, traditional ADRC control, linear quadratic regulator control, and dynamic inverse control. Therefore, research on the control of GEVs is relatively lacking compared to that of ordinary fixed-wing aircraft. Summary of the Invention

[0003] Purpose of the invention

[0004] To address the lack of existing research on the control of ground effect vehicles (GEVs), this invention provides a disturbance rejection control method for a longitudinal model of a GEV within the ground effect zone. First, a tracking differentiator is used to arrange the transient process between the desired input and the actual output of the system, minimizing initial value deviations. Second, a new nonlinear function is introduced to improve the extended observer, significantly enhancing the system's disturbance rejection capability and robustness. Finally, by introducing a new nonlinear function and improving the nonlinear feedback law, a system control law is obtained, greatly improving the system's control accuracy.

[0005] Invention Technology Solutions

[0006] A disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone includes the following steps:

[0007] Step 1: Linearize the small perturbation at the equilibrium point to establish a longitudinal system model of the ground effect vehicle in the ground effect zone;

[0008] Step 2: Based on the longitudinal system model of the ground effect vehicle established in Step 1, obtain the subsystem control models for pitch angle and elevator.

[0009] Step 3: Based on the subsystem control model established in Step 2, design a tracking differentiator for the disturbance rejection control method to track the desired input;

[0010] Step 4: Based on the subsystem control model established in Step 2, design a tracking differentiator for the disturbance rejection control method to track the actual output of the system;

[0011] Step 5: Introduce a new nonlinear function;

[0012] Step 6: Based on the nonlinear function designed in Step 5 and the tracking differentiator designed in Step 4 for tracking the actual output of the system, design a third-order extended state observer to estimate the system disturbance in real time and provide compensation in real time.

[0013] Step 7: Error e1 and error derivative e2;

[0014] Step 8: Obtain the nonlinear feedback law u0;

[0015] Step 9: Obtain the system control law.

[0016] Preferably, the longitudinal system model of the ground effect vehicle in step 1 within the ground effect zone is as follows:

[0017]

[0018] Where, x=[Vαqθh] T u = [δ e A and B are matrices of appropriate dimensions; x is the state vector, u is the control variable, V is the velocity, α is the angle of attack, q is the pitch rate, θ is the pitch angle, h is the altitude, and δ is the velocity. e It is an elevator.

[0019] Preferably, the subsystem control model in step 2 is as follows:

[0020]

[0021] Where x1 and x2 are state vectors, y is the pitch angle output, b is the amplification factor, w(t) is the external disturbance, and t is time; f(x1,x2,w(t),t) represents the total disturbance of the system, including internal and external disturbances.

[0022] Preferably, in the tracking differentiator of step 3:

[0023]

[0024] Wherein, fhan(v1-θ) * ,v2,r,h):

[0025]

[0026] Where, θ * For the desired pitch angle, v1 and v2 are the desired pitch angle tracking signals and their derivatives.r h and h are the tuning parameter and the filter factor, respectively.

[0027] Preferably, in the tracking differentiator of step 4:

[0028]

[0029] Where y is the actual pitch angle output, and y1 and y2 are the tracking signals of the actual pitch angle and their derivatives, respectively.

[0030] Preferably, the nonlinear function in step 5 is:

[0031] (1) When δ < |e| ≤ γ, the nonlinear function is designed as follows:

[0032] fal(e,α,δ,γ)=|e| α sign(e) (6)

[0033] (2) When |e|≤δ, the nonlinear function is designed as follows:

[0034] fal(e,α,δ,γ)=λ1sine+λ2sin 2 e+λ3sin 3 e (7)

[0035] (3) When |e|>γ, the nonlinear function is designed as follows:

[0036] fal(e,α,δ,γ)=γ α sign(e) (8)

[0037] To ensure that the piecewise function is continuous within its domain, and is differentiable and solvable at the breakpoints, the new function expression is:

[0038]

[0039] Where γ, α, and δ are positive constants greater than zero, and e is the error.

[0040] Preferably, the third-order extended state observer in step 6 is:

[0041]

[0042] Where z1, z2, and z3 are the outputs of the extended state observer, z1 and z2 are the state observation signals, z3 is the estimated internal and external disturbances of the system, b1, b2, and b3 are the design parameters of the state observer, which are also the three main parameters that are adjusted in the system and are determined by the state of the system, b0 is the estimated value of the amplification factor, e is the state error, y1 is the tracking signal of the actual pitch angle, and u is the control quantity of the system.

[0043] Preferably, in step 7, the error e1 and the error derivative e2 are calculated as follows:

[0044]

[0045] Preferably, the nonlinear feedback law u0 is calculated as follows:

[0046] u0 = b 01 fal(e1,α3,δ,γ)+b 02 fal(e2,α4,δ,γ) (12)

[0047] Among them, b 01 b 02 It is the proportionality coefficient.

[0048] Preferably, the system control law is:

[0049]

[0050] Where b0 is an estimated value of the system object magnification factor.

[0051] Advantages of this invention:

[0052] 1. From the simulation of this invention Figure 2 As can be seen, PID and traditional ADRC have different control effects. PID has an extremely fast output response speed, but it has a large overshoot and a long settling time. Traditional ADRC has a fast output response speed, but it also has a large overshoot and a long settling time. Compared with PID and traditional ADRC, the improved ADRC solves the contradiction between the system's response speed and overshoot, and the system's output response curve can quickly and well approach the system's expected output.

[0053] 2. From the simulation of the present invention Figures 3-6 As can be seen in the simulation Figure 3 Traditional ADRC and improved ADRC exhibit relatively small changes in pitch rate, meaning they cause less damage to the system; in simulations Figure 4 In the simulation, the improved ADRC control showed a smaller change in pitch angle error and higher control accuracy compared to PID and traditional ADRC control. Figure 5 In the extended state observer, z3 compensates for disturbances in the control law, thereby improving the energy required for control inputs in ADRC and increasing economic efficiency; in simulation Figure 5 In this study, compared with the traditional ADRC, the improved ADRC can accurately predict the total disturbance. Attached Figure Description

[0054] Figure 1 This is a diagram of the self-interference suppression structure.

[0055] Figure 2 This is a graph showing the change in pitch angle.

[0056] Figure 3 This is a graph showing the change in pitch rate.

[0057] Figure 4 This is a graph showing the change in pitch angle error.

[0058] Figure 5 This is a curve showing the change in the control quantity.

[0059] Figure 6 This is a graph showing the changes in disturbance. Detailed Implementation

[0060] The present invention is achieved through the following technical solution.

[0061] A disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone includes the following steps:

[0062] Step 1: Based on the unique characteristics of the mission of the ground effect vehicle (GEV) within the ground effect zone and the complexity of the flight environment, a longitudinal system model of the GEV within the ground effect zone is established using small perturbation linearization at the equilibrium point. The control model is described below:

[0063]

[0064] Where, x=[Vαqθh] T u = [δ e A and B are matrices of appropriate dimensions. x is the state vector, u is the control variable, V is the velocity, α is the angle of attack, q is the pitch rate, θ is the pitch angle, h is the altitude, and δ is the velocity. e It is an elevator.

[0065] Step 2: Based on the control model established in Step 1, the subsystem control models for pitch angle and elevator can be obtained, and their control models are described as follows:

[0066]

[0067] Where x1 and x2 are state vectors, y is the pitch angle output, b is the amplification factor, w(t) is the external disturbance, and t is time. f(x1,x2,w(t),t) represents the total disturbance of the system, including internal and external disturbances.

[0068] Step 3: Based on the control model established in Step 2, design a tracking differentiator for the disturbance rejection control method to track the desired input. In this tracking differentiator:

[0069]

[0070] Wherein, fhan(v1-θ) * ,v2,r,h):

[0071]

[0072] Where, θ * For the desired pitch angle, v1 and v2 are the desired pitch angle tracking signals and their derivatives, and r and h are the tuning parameter and the filtering factor, respectively.

[0073] Step 4: Based on the control model established in Step 2, design a tracking differentiator for the disturbance rejection control method to track the actual output of the system. In this tracking differentiator:

[0074]

[0075] Where y is the actual pitch angle output, and y1 and y2 are the tracking signals of the actual pitch angle and their derivatives, respectively.

[0076] Step 5: Introduce a new nonlinear function, which is:

[0077] (1) When δ < |e| ≤ γ, the new function is designed as follows:

[0078] fal(e,α,δ,γ)=|e| α sign(e) (19)

[0079] (2) When |e|≤δ, the new function is designed as follows:

[0080] fal(e,α,δ,γ)=λ1 sine+λ2 sin 2 e+λ3 sin 3 e (20)

[0081] (3) When |e|>γ, the new function is designed as follows:

[0082] fal(e,α,δ,γ)=γ α sign(e) (21)

[0083] To ensure that the piecewise function is continuous within its domain, and is differentiable and solvable at the breakpoints, the new function expression is:

[0084]

[0085] Where γ, α, and δ are positive constants greater than zero, and e is the error.

[0086] Step 6: Based on the new function designed in Step 5 and the output tracking differentiator of the actual system designed in Step 4, design the following third-order extended state observer to estimate the system disturbance in real time and provide real-time compensation:

[0087]

[0088] Where z1, z2, and z3 are the outputs of the extended state observer, z1 and z2 are the state observation signals, z3 is the estimated internal and external disturbances of the system, b1, b2, and b3 are the design parameters of the state observer, which are also the three main parameters that are adjusted in the system and are determined by the state of the system, b0 is the estimated value of the amplification factor, e is the state error, y1 is the tracking signal of the actual pitch angle, and u is the control quantity of the system.

[0089] Here, to avoid high-frequency oscillations, the fal function is used. The extended state observer is a dynamic process that only uses the input-output information of the original object, without using any information from functions describing the object's transitive relationships. The fundamental reason why z3 in the extended state observer can effectively track the real-time action of the system's acceleration is that as long as the system satisfies the observability condition, regardless of the form of acceleration, as long as it is acting, its effect will inevitably be reflected in the system's output. This is a concrete method for extracting the real-time action of the system's acceleration from the system's output information.

[0090] In summary, the designed extended state observer can estimate in real time numerous high-frequency unmodeled dynamics, uncertainties, and external disturbances such as wind and wave disturbances experienced by the ground effect vehicle, thereby enhancing the stability and robustness of the ground effect vehicle system.

[0091] Step 7: Subtract v1 and v2 from Step 3 and z1 and z2 from Step 6 to obtain the error e1 and the error differential e2:

[0092]

[0093] Feedback mechanisms are inherent in controlled systems but absent in classical dynamics. In controlled systems, feedback mechanisms also possess the ability to suppress small, uncertain disturbances. Different feedback forms vary in their ability to suppress disturbances; linear feedback is less efficient than some nonlinear state feedbacks. Nonlinear state feedback can be used to improve the dynamic characteristics of a closed-loop system, which is the core idea behind using state feedback to configure nonlinear dynamics in a closed loop.

[0094] Step 8: Based on fal(e,α,δ,γ) in Step 5 and e1 and e2 in Step 7, the nonlinear feedback law u0 is obtained as follows:

[0095] u0 = b 01 fal(e1,α3,δ,γ)+b 02 fal(e2,α4,δ,γ) (25)

[0096] Among them, b01 b 02 It is the proportionality coefficient.

[0097] Step 9: After designing the nonlinear feedback law, the system control law is obtained according to the active disturbance rejection control principle:

[0098]

[0099] Where b0 is an estimated value of the system object magnification factor.

[0100] The process of using the extended state observer to estimate the control quantity of a nonlinear control system and then transforming it into a linear control system is called dynamic compensation linearization. This process allows the system to be transformed into a cascaded integrator-type controlled system, regardless of whether the system is deterministic or uncertain, linear or nonlinear, or time-varying or time-invariant. Therefore, the extended state observer compensation method offers a unified approach to handling control problems of deterministic and uncertain, linear and nonlinear, and time-varying or time-invariant control systems.

[0101] To verify the effectiveness of the stabilizer based on active disturbance rejection control (ADRC) technology designed above, this invention utilizes full-process digital simulation to debug and test the ADRC controller, studies the engineering application of the model, and compares it with traditional PID and ADRC control. Figures 2-6 .

[0102] The scope of protection of this invention is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its scope. If such modifications and variations fall within the scope of the claims of this invention and their equivalents, then the intent of this invention also includes these modifications and variations.

Claims

1. A disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone, characterized in that, Includes the following steps: Step 1: Linearize the small perturbation at the equilibrium point to establish a longitudinal system model of the ground effect vehicle in the ground effect zone; Step 2: Based on the longitudinal system model of the ground effect vehicle established in Step 1, obtain the subsystem control models for pitch angle and elevator. Step 3: Based on the subsystem control model established in Step 2, design a tracking differentiator for the disturbance rejection control method to track the desired input; Step 4: Based on the subsystem control model established in Step 2, design a tracking differentiator for the disturbance rejection control method to track the actual output of the system; Step 5: Introduce a new nonlinear function; the nonlinear function in Step 5 is: (1) When When the nonlinear function is designed as follows: （6） (2) When When the nonlinear function is designed as follows: （7） (3) When When the nonlinear function is designed as follows: （8） To ensure that the piecewise function is continuous within its domain, and is differentiable and solvable at the breakpoints, the new function expression is: （9） in, , , For positive positive integers, This is the error. Step 6: Based on the nonlinear function designed in Step 5 and the tracking differentiator designed in Step 4 for tracking the actual output of the system, design a third-order extended state observer to estimate the system disturbance in real time and provide real-time compensation; the third-order extended state observer in Step 6 is: （10） in, , , It is the output of the extended state observer. , For state observation signals, It estimates the internal and external disturbances of the system. , , These are the design parameters of the state observer, and also the three main parameters that are adjusted in the system, determined by the system's state. This is an estimate of the magnification factor. It is a state error. The tracking signal is the actual pitch angle. It is the system's control variable. Step 7: Error Sum of error differentials ; Step 8: Obtain the nonlinear feedback law ; Step 9: Obtain the system control law.

2. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 1, characterized in that, The longitudinal system model of the ground effect vehicle in step 1 within the ground effect zone is as follows: （1） in, , , , A matrix of appropriate dimension; For state vectors, To control the quantity, For speed, For the angle of attack, For pitch rate, The pitch angle, For height, It is an elevator.

3. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 2, characterized in that, The subsystem control model in step 2 is as follows: （2） in, , For state vectors, For pitch angle output, This is the magnification factor. External disturbances For time; This represents the total disturbance of the system, including internal and external disturbances.

4. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 3, characterized in that, In the tracking differentiator in step 3: （3） in, : （4） in, For the desired pitch angle, , Divided into the desired pitch angle tracking signal and its derivative, , These are the tuning parameter and the filter factor, respectively.

5. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 4, characterized in that, In the tracking differentiator in step 4: （5） in, This is the actual pitch angle output. , These are the tracking signals for the actual pitch angle and their derivatives.

6. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 1, characterized in that, Error in step 7 Sum of error differentials The calculation is as follows: 。 7. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 6, characterized in that, Nonlinear feedback law The calculation is as follows: （12） in, , It is the proportionality coefficient.

8. The disturbance rejection control method for a longitudinal model of a ground effect vehicle within the ground effect zone as described in claim 7, characterized in that, The system control law is: （13） in, It is an estimated value of the system object magnification factor.

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