A design method of acceleration feedback autopilot based on statically unstable missile

Abstract

The application discloses a design method of an acceleration feedback autopilot based on a static unstable missile, and comprises the following steps: establishing a longitudinal linear dynamic equation; constructing an acceleration autopilot framework; setting acceleration autopilot control parameters to obtain an autopilot; and controlling the flight state of a flight vehicle by using the autopilot, wherein the acceleration autopilot framework is a three-loop autopilot structure, comprising a damping stable inner loop, a stability enhancement loop and an acceleration loop outer loop, the feedback signal of the damping stable inner loop is generated based on a pitch angular velocity, the feedback signal of the stability enhancement loop is generated based on a longitudinal acceleration, and the feedback signal of the acceleration loop outer loop is generated based on the longitudinal acceleration. The method disclosed by the application can stabilize and control a static unstable flight vehicle, and significantly improves the overload capacity of the static unstable flight vehicle.

Description

Technical Field

[0001] This invention relates to a design method for an acceleration feedback autopilot based on a statically unstable projectile, belonging to the field of aircraft control technology. Background Technology

[0002] The core task of an autopilot is to ensure that the aircraft accurately and robustly tracks the command signals generated by the guidance system, enabling the aircraft to generate corresponding control forces and torques according to the command signals, thereby allowing the aircraft to fly stably until it hits the target.

[0003] Most existing autopilots use the classic three-loop autopilot, which has a good control effect on traditional aircraft. However, for statically unstable aircraft, when the aircraft is disturbed by external disturbances and deviates from its equilibrium state, the aerodynamic torque generated by the missile at the moment the disturbance disappears causes the aircraft to deviate further from its original equilibrium position, and the control effect of the classic three-loop autopilot becomes significantly worse.

[0004] Therefore, it is necessary to further study existing autopilots to address the problem of poor control of statically unstable aircraft. Summary of the Invention

[0005] To overcome the above problems, the inventors conducted in-depth research and proposed a design method for an acceleration feedback autopilot based on a statically unstable spring, comprising:

[0006] S1. Establish the longitudinal linear dynamic equation;

[0007] S2. Construct the framework for the acceleration autopilot;

[0008] S3. Set the control parameters for the acceleration autopilot to obtain the autopilot;

[0009] S4. Use an autopilot to control the flight status of the aircraft.

[0010] In a preferred embodiment, in S1, the longitudinal linear dynamic equation is expressed as:

[0011]

[0012] Where α represents the angle of attack, b α b represents the pitch force generated by the angle of attack. δ δ represents the pitch force caused by the elevator. e Indicates the rudder deflection angle. Indicates the pitch angle, a α a represents the pitching moment caused by the angle of attack. ω a represents the pitch damping moment caused by the pitch angular velocity. δThe pitch moment caused by the elevator is represented by θ, the trajectory angle is represented by V, the flight speed is represented by c, the distance of the accelerometer mounting position from the center of mass is represented by a. y It represents longitudinal acceleration.

[0013] In a preferred embodiment, in S2, the acceleration autopilot frame includes a pitch loop autopilot and a yaw loop autopilot.

[0014] The yaw loop autopilot structure is symmetrically arranged with the pitch loop autopilot structure.

[0015] In a preferred embodiment, the pitch loop autopilot is a three-loop autopilot structure, including a damping stabilization inner loop, a stability enhancement loop, and an acceleration loop outer loop, wherein the feedback signal of the damping stabilization inner loop is based on the pitch angular velocity. The feedback signal for generating and stabilizing the loop is based on the longitudinal acceleration a. y The feedback signal generated from the outer loop of the acceleration loop is based on the longitudinal acceleration a. y generate.

[0016] In a preferred embodiment, an acceleration gain K is provided in the outer loop of the acceleration loop. ac For longitudinal acceleration a y The gain is applied, and the amplified signal serves as the feedback signal for the outer loop of the acceleration circuit.

[0017] In a preferred embodiment, a stabilization gain K is provided in the stability enhancement loop. I For longitudinal acceleration a y The gain is applied, and the amplified signal is used as the feedback signal for the stability enhancement loop.

[0018] In a preferred embodiment, an angular velocity gain K is provided in the damped stabilizing inner loop. G +cK ac K A For pitch angular velocity The gain is applied, and the amplified signal serves as the feedback signal for the damped stabilization inner loop.

[0019] In a preferred embodiment, a closed-loop gain K is provided in the pitch loop autopilot. DC , used to respond to the input acceleration command a yc Adjust the gain, and then use the acceleration command a′ after obtaining the gain. yc It is superimposed on the feedback signal of the outer loop of the acceleration loop, and then passed through the proportional module K. A Points module Then, it is superimposed with the feedback signal from the stability enhancement loop and the feedback signal from the damping stability inner loop, and after passing through the servo motor gain, it generates the rudder deflection angle δ.e Based on rudder deflection angle δ e The longitudinal acceleration 'a' is obtained by solving the longitudinal linear dynamic equation. y .

[0020] In a preferred embodiment, in S3, the acceleration autopilot control parameters are set as follows:

[0021]

[0022]

[0023]

[0024] Where k1, k2, and k3 are intermediate variables, set as follows:

[0025]

[0026] The beneficial effects of this invention include:

[0027] (1) Improve the overload capacity of the aircraft: By appropriately selecting the parameters of the damping circuit, the statically unstable aircraft can be stabilized and controlled, and the overload capacity of the statically unstable aircraft can be significantly improved.

[0028] (2) Achieve rapid response: Through acceleration feedback, the autopilot can quickly sense the dynamic changes of the aircraft and make corresponding adjustments and controls in a timely manner, enabling the aircraft to achieve rapid response and precise strike in a short period of time;

[0029] (3) Simplified control system design: Traditional statically unstable aircraft usually require complex control systems and algorithms to maintain stability and accurate strikes, while the acceleration feedback autopilot provided by this invention can simplify control system design and reduce manufacturing and maintenance costs. Attached Figure Description

[0030] Figure 1 A schematic flowchart of an acceleration feedback autopilot design method based on a statically unstable spring, according to a preferred embodiment of the present invention, is shown.

[0031] Figure 2 A schematic diagram of the acceleration autopilot frame structure is shown in the acceleration feedback autopilot design method based on a statically unstable spring according to a preferred embodiment of the present invention.

[0032] Figure 3 The simulation diagram of the output response curve in Example 1 is shown. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0034] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0035] According to the present invention, an acceleration feedback autopilot design method based on a statically unstable spring is provided, such as... Figure 1 As shown, it includes the following steps:

[0036] S1. Establish the longitudinal linear dynamic equation;

[0037] S2. Construct the framework for the acceleration autopilot;

[0038] S3. Set the control parameters for the acceleration autopilot to obtain the autopilot;

[0039] S4. Use an autopilot to control the flight status of the aircraft.

[0040] In S1, the longitudinal linear dynamic equation is expressed as:

[0041]

[0042] Where α represents the angle of attack, b α b represents the pitch force generated by the angle of attack. δ δ represents the pitch force caused by the elevator. e Indicates the rudder deflection angle. Indicates the pitch angle, a α a represents the pitching moment caused by the angle of attack. ω a represents the pitch damping moment caused by the pitch angular velocity. δ The pitch moment caused by the elevator is represented by θ, the trajectory angle is represented by V, the flight speed is represented by c, the distance of the accelerometer mounting position from the center of mass is represented by a. y Represents longitudinal acceleration. Let α, ω z As a state variable x, a y ,∫a y ,ω z As the output y, the state equation of the longitudinal linear dynamic equation is expressed as:

[0043]

[0044] y = Cx + Du

[0045]

[0046]

[0047] in, Indicates the pitch angle.

[0048] In S2, the acceleration autopilot frame includes a pitch loop autopilot and a yaw loop autopilot;

[0049] The yaw loop autopilot structure is symmetrically arranged with the pitch loop autopilot structure.

[0050] In traditional autopilots, the feedback signals are typically pitch angle, pitch rate, and longitudinal acceleration. For statically unstable aircraft, when the aircraft is disturbed by external disturbances and deviates from its equilibrium state, the traditional autopilot will cause the aircraft to deviate further from its original equilibrium position the instant the disturbance disappears.

[0051] In this invention, the pitch loop autopilot is a three-loop autopilot structure, including a damping stabilization inner loop, a stability enhancement loop, and an acceleration loop outer loop, as shown below. Figure 2 As shown, the feedback signal of the damping stabilization inner loop is based on the pitch angular velocity. The feedback signal for generating and stabilizing the loop is based on the longitudinal acceleration a. y The feedback signal generated from the outer loop of the acceleration loop is based on the longitudinal acceleration a. y generate.

[0052] Preferably, an acceleration gain K is provided in the outer loop of the acceleration loop. ac For longitudinal acceleration a y The gain is applied, and the amplified signal serves as the feedback signal for the outer loop of the acceleration circuit.

[0053] A stabilization gain K is set in the stability enhancement loop. I For longitudinal acceleration a y The gain is applied, and the amplified signal serves as the feedback signal for the stability enhancement loop.

[0054] An angular velocity gain K is set in the damped stabilizing inner loop. G +cK ac K A For pitch angular velocity The gain is applied, and the amplified signal serves as the feedback signal for the damped stabilization inner loop.

[0055] The pitch angular velocity Based on longitudinal acceleration a y The solution is obtained by solving the longitudinal linear dynamic equation.

[0056] Furthermore, a closed-loop gain K is provided in the pitch loop autopilot. DC , used to respond to the input acceleration command a yc Adjust the gain, and then use the acceleration command a′ after obtaining the gain. yc It is superimposed on the feedback signal of the outer loop of the acceleration loop, and then passed through the proportional module K. A Points module Then, it is superimposed with the feedback signal of the stability enhancement loop and the feedback signal of the damping stability inner loop, and then processed by the servo gain K. ACT The rudder deflection angle δ is generated afterward. e Based on rudder deflection angle δ e The longitudinal acceleration 'a' is obtained by solving the longitudinal linear dynamic equation. y .

[0057] The acceleration autopilot framework provided by this invention can greatly improve the system stability of statically unstable aircraft compared to traditional autopilots. Furthermore, compared to other autopilots, the stability enhancement loop in this invention uses longitudinal acceleration α. y As a feedback signal, it enables statically unstable aircraft to respond more quickly, allowing them to achieve rapid response and precision strikes in a short period of time.

[0058] Based on longitudinal acceleration a y The pitch angular velocity is obtained by solving the longitudinal linear dynamic equation. Based on rudder deflection angle δ e The longitudinal acceleration 'a' is obtained by solving the longitudinal linear dynamic equation. y The specific solution process is not described in detail in this invention, but those skilled in the art can do so based on experience.

[0059] Furthermore, the acceleration gain K ac Closed-loop gain K DC , Proportional module K A Points module Servo gain K ACT These are all commonly used gains or modules in autopilots. In this invention, the specific settings of their parameters are not limited, and those skilled in the art can set them freely.

[0060] Preferably, the servo gain K ACT Set as a constant term.

[0061] In S3, when setting the control parameters of the acceleration autopilot, without considering the dynamics of hardware such as accelerometers and angular rate gyroscopes, and placing all feedback at the servo motor, the following can be obtained:

[0062]

[0063] Combining the state equations of the longitudinal dynamic equations, the state feedback matrix can be obtained as follows:

[0064]

[0065] Among them, k1, k2, and k3 are intermediate variables.

[0066] The output feedback matrix is:

[0067]

[0068]

[0069] From the relationship between the output feedback matrix and the state feedback matrix, we can obtain:

[0070]

[0071] According to the pole placement method, the control parameters of the acceleration autopilot can be obtained:

[0072]

[0073]

[0074]

[0075] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0076] Example

[0077] Example 1

[0078] The simulation experiment was conducted, and the driver's instrument was obtained through the following methods:

[0079] S1. Establish the longitudinal linear dynamic equation;

[0080] S2. Construct the framework for the acceleration autopilot;

[0081] S3. Set the control parameters for the acceleration autopilot to obtain the autopilot.

[0082] In S1, the longitudinal linear dynamic equation is expressed as:

[0083]

[0084] In S2, the acceleration autopilot frame includes a pitch loop autopilot and a yaw loop autopilot, wherein the pitch loop autopilot structure is as follows: Figure 2 As shown, the yaw loop autopilot structure and the pitch loop autopilot structure are arranged symmetrically.

[0085] In S3, the acceleration autopilot control parameters are set as follows:

[0086]

[0087]

[0088]

[0089]

[0090] During the simulation, a statically unstable missile was used as the simulation object. The missile was simulated using perturbed feature points, specifically: a α =-175, b α =1.67, V = 359; during the simulation, k is set... ACT =-1, K is obtained through S3 calculation A =0.0142, K I =0.0055, K G =0.0907.

[0091] During the simulation, the input acceleration command was set to a square wave signal of 1 m / s². 2 3m / s 2 2m / s 2 The frequency of the driver instrument was set to 5 rad / s, 15 rad / s, and 33 rad / s respectively, and the output response curves were obtained as follows: Figure 3 As shown.

[0092] As can be seen from the figure, the longitudinal acceleration of the statically unstable missile can reach a corresponding stable state after receiving a changing square wave signal. At the same time, the autopilot frequency has little effect on the stable state. When the autopilot frequency increases, the system response time decreases, that is, the response speed increases.

[0093] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. A design method for an acceleration feedback autopilot based on a statically unstable spring, characterized in that, include: S1. Establish the longitudinal linear dynamic equation; S2. Construct the framework for the acceleration autopilot; S3. Set the control parameters for the acceleration autopilot to obtain the autopilot; S4. Use an autopilot to control the flight status of the aircraft; In S2, the acceleration autopilot frame includes a pitch loop autopilot and a yaw loop autopilot; The yaw loop autopilot structure and the pitch loop autopilot structure are symmetrically arranged. The pitch loop autopilot is a three-loop autopilot structure, including a damped stabilization inner loop, a stability enhancement loop, and an acceleration loop outer loop. The feedback signal of the damped stabilization inner loop is based on the pitch angular velocity. The feedback signal for the generation and stability enhancement loop is based on longitudinal acceleration. The feedback signal generated from the outer loop of the acceleration loop is based on longitudinal acceleration. generate; An acceleration gain is set in the outer loop of the acceleration circuit. For longitudinal acceleration The gain is applied, and the amplified signal is used as the feedback signal for the outer loop of the acceleration loop; In S3, the acceleration autopilot control parameters are set as follows: , , , in, , , As an intermediate variable, set it as follows: , Indicates the proportion module, Indicates stable gain. Indicates flight speed. This indicates the pitch force caused by the elevator. This indicates the distance of the accelerometer's installation location from the center of mass. This indicates the pitch moment caused by the elevator. Indicates servo gain. Indicates acceleration gain. This represents the pitch force generated by the angle of attack. This represents the pitching moment caused by the angle of attack. This represents the pitch damping torque caused by the pitch angular velocity.

2. The design method for an autopilot based on statically unstable springs according to claim 1, characterized in that, In S1, the longitudinal linear dynamic equation is expressed as: , in, Indicates angle of attack. Indicates the rudder deflection angle. Indicates pitch angle, Indicates the trajectory inclination angle, It represents longitudinal acceleration.

3. The design method for an autopilot based on statically unstable springs according to claim 1, characterized in that, A stabilizing gain is set in the stability enhancement loop. For longitudinal acceleration The gain is applied, and the amplified signal serves as the feedback signal for the stability enhancement loop.

4. The design method for an autopilot based on statically unstable springs according to claim 1, characterized in that, An angular velocity gain is set in the damped stabilizing inner loop. For pitch angular velocity The gain is applied, and the amplified signal serves as the feedback signal for the damped stabilization inner loop.

5. The design method for an autopilot based on statically unstable springs according to claim 1, characterized in that, The pitch loop autopilot is equipped with a closed-loop gain. Used to input acceleration commands. Gain adjustment, and then acceleration command after gain is obtained. It is superimposed on the feedback signal of the outer loop of the acceleration loop, and then passed through the proportional module. Points module Then, it is superimposed with the feedback signal from the stability enhancement loop and the feedback signal from the damping stability inner loop, and after passing through the servo motor gain, the rudder deflection angle is generated. Based on rudder deflection angle The longitudinal acceleration is obtained by solving the longitudinal linear dynamic equation. .

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