Rotary aircraft strapdown image tracking navigation method, medium and equipment

Abstract

The invention discloses a rotating aircraft strapdown image tracking navigation method and device and a storage medium, and the method comprises the steps: building an aircraft nonlinear dynamic model through delay calculation, optics and detector angle measurement, carrying out sampling holding and angular motion to extract sight angle output, and carrying out intermittent control to obtain a strapdown image through an intermittent control method; the aircraft is kept flying at a constant angle of attack over a period of time. A rotating aircraft nonlinear kinetic model is constructed based on a full attack angle equation, aircraft attitude angle and sight angle information is decoupled, the full attack angle and aircraft orbit simulation precision is improved, and finally the aircraft guiding method is determined.

Description

Technical Field

[0001] The present invention relates to the technical field of UAV tracking, and particularly to a strapdown image tracking and navigation method, medium and device for a rotary aircraft. Background Art

[0002] Tracking and navigation enables an unmanned aerial vehicle to continuously track a moving target. The strapdown method can eliminate the need for a pan-tilt unit, offering advantages such as low cost and easy maintenance. However, the strapdown method cannot isolate the attitude motion of the aircraft, making it extremely difficult to extract line-of-sight angle information. To address this, this patent obtains the flight angle of attack of the aircraft by solving the full angle of attack equation, and then extracts the line-of-sight angle information. Additionally, an intermittent control method is utilized to achieve constant angle-of-attack flight of the aircraft within a short period to ensure the solvability of the full angle of attack equation. Summary of the Invention

[0003] A strapdown image tracking and navigation method for a rotary aircraft proposed by the present invention can solve at least one of the technical problems in the background art.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A strapdown image tracking and navigation method for a rotary aircraft includes the following steps:

[0006] S100. Build a non-linear dynamic model of the aircraft, perform sampling and holding, and extract angular motion;

[0007] S200. Combine with the full angle of attack equation of the rotary aircraft to construct a decoupled model of the non-linear dynamic model of the aircraft;

[0008] S300. Based on the decoupled model, combine with the navigation method to obtain the full angle of attack data of the aircraft and extract the line-of-sight angle data;

[0009] S400. Determine the aircraft guidance method according to the line-of-sight angle data and the body line-of-sight angle data in combination with the intermittent control method.

[0010] Further, in step S100 of the present invention, the non-linear dynamic model of the aircraft includes:

[0011] In the non-linear dynamic model of the aircraft, ε is the body line-of-sight angle, τ is the delay time of the camera and image processing, Ks is the scale factor, λ is the zero position error and the noise caused by image processing uncertainty; τ0 is the sampling period; Kη is the angular motion extraction coefficient brought by the angle of attack and nutation.

[0012] Further, in step S100 of the present invention, the angular motion extraction method is:

[0013]

[0014] Among them, α is the angle of attack, θ is the flight path angle, and ε is the line-of-sight angle. is the pitch angle.

[0015] Furthermore, the decoupling model method of the S200 of the present invention for constructing the nonlinear dynamics model of the aircraft in combination with the full angle of attack equation of the rotary aircraft includes:

[0016] The full angle of attack calculation method is:

[0017]

[0018] In the above formula, Δ is the full angle of attack, θ is the flight path angle, γ is the roll angle of the aircraft, v is the motion speed of the aircraft, the angular velocity of the flight path angle, the angular acceleration of the flight path angle, the angular acceleration of the roll angle of the aircraft, is the angular velocity of the roll angle of the aircraft, A is the equatorial moment of inertia, C is the polar moment of inertia, β D is the dynamic imbalance angle, Δ M0 is the initial aerodynamic eccentricity angle, ω ⊥ is the wind speed, i is a complex number, and the definitions of the parameters H, P, T, and M are shown in the following formula:

[0019]

[0020] Among them, b y , k y , k z , k zz , b z The parameters are aerodynamic parameters;

[0021] The dynamic imbalance angle of the aircraft is very small. Ignoring the initial aerodynamic eccentricity angle and considering that the wind speed is a small quantity relative to the aircraft speed, the last three terms on the right side of Equation (2) are all ignored and rewritten as:

[0022]

[0023] Furthermore, the navigation method in step S300 of the present invention includes: fixed flight path angle constraint and fixed angle of attack constraint. Among them, the fixed flight path angle constraint:

[0024] If the fixed flight path angle constraint navigation method is adopted, the flight trajectory in the image tracking navigation process can be approximated as a straight line. At this time, the flight path angle θ remains basically unchanged, that is, the right side of Equation (4) is equal to 0, and then Equation (4) can be transformed into a homogeneous equation, as shown in Equation (5).

[0025] Δ″+(H - iP)Δ′-(M + iPT)Δ = 0 (5)

[0026] Equation (5) can have an analytical solution, which is described in the following form:

[0027]

[0028] Wherein:

[0029]

[0030] Fixed angle of attack constraint: If the fixed angle of attack constraint navigation method is adopted, then Equation (4) is written as:

[0031]

[0032] That is:

[0033]

[0034] Furthermore, in step S400 of the present invention, the method for determining the flight vehicle guidance method based on the line-of-sight angle data and the body line-of-sight angle data in combination with the intermittent control method includes:

[0035]

[0036] Wherein, A′ MN is the required overload, is the fixed angle of attack flight time, n is the proportionality coefficient, v is the flight vehicle speed, i ∈ N+, k ∈ N, ε1 is the minimum angle of attack holding time, and ε2 is the line-of-sight angle rate error threshold.

[0037] On the other hand, the present invention also discloses a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the processor is caused to execute the steps of the above method.

[0038] On yet another aspect, the present invention also discloses a computer device including a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, the processor is caused to execute the steps of the above method.

[0039] As can be seen from the above technical solutions, for the strapdown image tracking navigation method, device and storage medium of the rotating flight vehicle of the present invention, the present invention constructs a non-linear dynamics model of the rotating flight vehicle based on the full angle of attack equation, successfully decouples the attitude angle and line-of-sight angle information of the flight vehicle, and the accuracy can meet the requirements of engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the non-linear dynamic model of the flight vehicle of the present invention;

[0041] Figure 2 is a flow chart of the line-of-sight angle calculation of the flight vehicle;

[0042] Figure 3 is a schematic diagram of the simulation result of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0044] The strapdown image tracking navigation method for a rotary aircraft described in this embodiment specifically includes the following steps:

[0045] S100. Build a nonlinear dynamics model of the aircraft, perform sampling and holding, and extract angular motion;

[0046] S200. Combine the full angle of attack equation of the rotary aircraft to construct a decoupling model of the nonlinear dynamics model of the aircraft;

[0047] S300. Based on the decoupling model, combine the navigation method to obtain the full angle of attack data of the aircraft and extract the line-of-sight angle data;

[0048] S400. Determine the guidance method of the aircraft according to the line-of-sight angle data and the body line-of-sight angle data in combination with the intermittent control method.

[0049] The following will explain each step in detail:

[0050] S100. Build a nonlinear dynamics model of the aircraft, perform sampling and holding, and extract angular motion

[0051] The core function of the strapdown image tracking device is to measure the line-of-sight angle difference between the target and the aircraft, and its characteristics are mainly determined by the calculation delay, optical and detector angle measurement, sampling and holding, and angular motion extraction output.

[0052] As Figure 1 shown in the figure is the nonlinear dynamics model of the aircraft. In the nonlinear dynamics model of the aircraft, ε is the body line-of-sight angle, τ is the delay time of the camera and image processing, Ks is the scale factor, λ is the zero position error and the noise caused by image processing uncertainty; τ0 is the sampling period; Kη is the angular motion extraction coefficient brought by the angle of attack and nutation.

[0053] Considering the navigation problem in the plumb plane, the tracking navigation of the aircraft usually needs to obtain the line-of-sight angle q. However, the strapdown method does not have a stable platform to isolate the attitude of the aircraft. Therefore, it can only measure the body line-of-sight angle ε in the aircraft coordinate system. To obtain the line-of-sight angle q in the geodetic coordinate system, the pitch angle of the aircraft needs to be measured

[0054] Among them, q, ε, α, θ have the following mathematical relationship:

[0055]

[0056] In the formula, α is the angle of attack and θ is the flight path angle.

[0057] S200. Construct a decoupled model of the nonlinear dynamics model of the aircraft by combining the full angle of attack equation of the rotary aircraft;

[0058] Theoretically, the pitch angle of the aircraft can be obtained through a microelectromechanical inertial measurement unit (MEMSIMU). However, the application of MEMSIMU in rotary aircraft still needs to overcome the problems of obtaining the initial roll angle and the contradiction between a large measurement range and high precision under high rotational speed conditions. Therefore, it is not very feasible to use MEMSIMU to obtain the pitch angle of the aircraft to isolate the attitude of the aircraft. In this regard, this solution constructs a decoupled model of the high-dynamic angular motion of the aircraft by introducing the full angle of attack equation of the rotary aircraft.

[0059] The full angle of attack equation is shown as follows:

[0060]

[0061] In the above formula, Δ is the full angle of attack, θ is the flight path angle, γ is the roll angle of the aircraft, v is the motion speed of the aircraft, is the angular velocity of the flight path angle, is the angular acceleration of the flight path angle, is the angular acceleration of the roll angle of the aircraft, is the angular velocity of the roll angle of the aircraft, A is the equatorial moment of inertia, C is the polar moment of inertia, β D is the dynamic unbalance angle, Δ M0 is the initial aerodynamic eccentricity angle, ω ⊥ is the wind speed, i is a complex number, and the definitions of the parameters H, P, T, and M are shown as follows

[0062]

[0063] Among them, b y , k y , k z , k zz , b z The parameters are aerodynamic parameters.

[0064] Actually, the dynamic unbalance angle of the aircraft is very small, the initial aerodynamic eccentricity angle can also be ignored, and the wind speed is also a small quantity relative to the speed of the aircraft. The last three terms on the right side of Equation (2) can all be ignored and can be rewritten as:

[0065]

[0066] S300. Obtain the full angle of attack data of the aircraft based on the decoupled model in combination with the navigation method, and extract the line-of-sight angle data;

[0067] The navigation method can be divided into two cases:

[0068] 1. Fixed track angle constraint

[0069] If the fixed track angle constraint navigation method is adopted, the flight track in the image tracking navigation process can be approximated as a straight line. At this time, the track angle θ remains basically unchanged, that is, the right side of Equation (4) is equal to 0, so Equation (4) can be transformed into a homogeneous equation, as shown in Equation (5).

[0070] Δ″+(H - iP)Δ′-(M + iPT)Δ = 0 (5)

[0071] Equation (5) can have an analytical solution and can be described in the following form:

[0072]

[0073] Where:

[0074]

[0075] 2. Fixed angle of attack constraint

[0076] If the fixed angle of attack constraint navigation method is adopted, then Equation (4) can be written as:

[0077]

[0078] That is:

[0079]

[0080] To sum up, if an appropriate navigation method is adopted, an analytical solution for the full angle of attack can be obtained, and the line-of-sight angle q in the inertial system can be extracted according to Equation (4).

[0081] S400. Determine the aircraft guidance method based on the line-of-sight angle data and the body line-of-sight angle data in combination with the intermittent control method.

[0082] As Figure 2 shown, in order to ensure the accurate extraction of the line-of-sight angle, the intermittent control method can be adopted to keep the aircraft flying at a constant angle of attack for a period of time. For the aircraft, the angle of attack is mainly generated by the servo driving the control surface according to the instructions of the navigation system. Therefore, as long as the required overload of the aircraft is kept constant, the fixed angle of attack flight can be achieved. The designed guidance method is as follows:

[0083]

[0084] Among them, A′ MN is the required overload, $t$ is the flight time at a fixed angle of attack, $n$ is the proportionality coefficient, $v$ is the speed of the aircraft, $i\in N^+$, $k\in N$, $\varepsilon_1$ is the minimum angle-of-attack holding time, and $\varepsilon_2$ is the threshold of the line-of-sight angle rate error. Intermittent control can be used to make the aircraft fly at a constant angle of attack for a period of time to ensure that an analytical solution can be obtained for Equation (4), so as to calculate the flight angle of attack of the aircraft and solve the line-of-sight angle.

[0085] As Figure 3 shown, it is the result of digital simulation verification of this method using Matlab.

[0086] From Figure 3 it can be seen that the line-of-sight angle calculated using the algorithm of this patent is basically consistent with the actual value, meeting the requirements of the navigation system. The simulation results also further verify the effectiveness of the guidance algorithm and the line-of-sight angle extraction method designed in this patent.

[0087] On the other hand, the present invention also discloses a computer-readable storage medium storing a computer program, which when executed by a processor causes the processor to execute the steps of the above method.

[0088] On yet another aspect, the present invention also discloses a computer device including a memory and a processor, where the memory stores a computer program, and when the computer program is executed by the processor, it causes the processor to execute the steps of the above method.

[0089] In another embodiment provided by the present application, a computer program product including instructions is also provided, which when running on a computer causes the computer to execute any one of the rotation aircraft strapdown image tracking navigation methods in the above embodiments.

[0090] It can be understood that the systems, devices, and storage media provided in the embodiments of the present invention correspond to the methods provided in the embodiments of the present invention, and the explanations, examples, and beneficial effects of the relevant content can refer to the corresponding parts in the above methods.

[0091] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0092] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including", or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or device that includes a series of elements includes not only those elements but also other elements not expressly listed, or elements that are inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article, or device that includes the element.

[0093] Each embodiment in this specification is described in a related manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements 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. A strapdown image tracking and navigation method for a rotating aircraft, characterized in that: The following steps are involved: S100, build a nonlinear dynamic model of the aircraft, perform sampling and holding, and extract angular motion; S200, constructing a decoupling model of the aircraft nonlinear dynamics model in combination with the total angle of attack equation of the rotating aircraft; S300, acquiring the aircraft total angle of attack data based on the decoupling model combined with the navigation method, and extracting the sight angle data; S400, determining the aircraft guidance method based on the line of sight angle data and the volume line of sight angle data in combination with the intermittent control method.

2. The rotating aircraft strapdown image tracking and navigation method according to claim 1, characterized in that: The aircraft nonlinear dynamics model in step S100 includes: In the nonlinear dynamic model of the actuator, ε is the stereo line of sight angle, τ is the delay time of the camera and image processing, Ks is the scale factor, λ is the zero position error and the noise caused by image processing uncertainty; τ0 is the sampling period; Kη is the angular motion extraction coefficient caused by the angle of attack and nutation.

3. The strapdown image tracking and navigation method for a rotating aircraft according to claim 1, characterized in that: The angular motion extraction method in step S100 is: Among them, α is the angle of attack, θ is the track angle, ε is the line of sight angle, is the pitch angle.

4. The strapdown image tracking and navigation method for a rotating aircraft according to claim 1, characterized in that: S200, a decoupling model method for constructing a nonlinear dynamic model of an aircraft in combination with a rotating aircraft full angle of attack equation includes: The total angle of attack is calculated as: In the above formula, Δ is the total angle of attack, θ is the track angle, γ is the aircraft roll angle, v is the aircraft speed, Angular velocity of the track angle, Angular acceleration of the track angle, Angular acceleration of the aircraft's roll angle, is the angular velocity of the aircraft roll angle, A is the equatorial moment of inertia, C is the polar moment of inertia, β D is the dynamic imbalance angle, Δ M0 is the initial aerodynamic eccentricity angle, ω ⊥ is the wind speed, i is a complex number, and the definitions of parameters H, P, T, and M are as follows: Among them, b y , k y , k z , k zz 、b z The parameters are aerodynamic parameters; The dynamic imbalance angle of the aircraft is very small, the initial aerodynamic eccentricity angle is ignored, the wind speed is small relative to the aircraft speed, the last three terms on the right side of equation (2) are ignored, and it is rewritten as:

5. The strapdown image tracking and navigation method for a rotating aircraft according to claim 1, characterized in that: The navigation method in step S300 includes: fixed track angle constraint and fixed attack angle constraint Among them, fixed track angle constraint: If the fixed track angle constrained navigation method is adopted, the flight trajectory of the image tracking navigation process can be approximated to a straight line. At this time, the track angle θ remains basically unchanged, that is, the right side of equation (4) is equal to 0. Then equation (4) can be transformed into a homogeneous equation, as shown in equation (5). Δ″+(H-iP)Δ′-(M+iPT)Δ=0 (5) Equation (5) can have an analytical solution, which can be described as follows: in: Fixed angle of attack constraint: If the fixed angle of attack constraint navigation method is adopted, equation (4) can be written as: Right now:

6. The strapdown image tracking and navigation method for a rotating aircraft according to claim 1, characterized in that: In step S400, the method for determining the aircraft guidance method based on the sight angle data and the stereoscopic sight angle data combined with the intermittent control method includes: Among them, A′ MN To use overload, is the flight time at a fixed angle of attack, n is the proportional coefficient, v is the aircraft speed, i∈N+, k∈N, ε1 is the minimum angle of attack holding time, and ε2 is the line of sight angular rate error threshold.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor is caused to perform the method according to any one of claims 1 to 6.

8. A computer device comprising a memory and a processor, characterized in that: The memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method according to any one of claims 1 to 6.

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