CN106802672B - A Real-time Closed-Loop Tracking Method Based on Rotating Biprism - Google Patents

Abstract

The invention discloses a real-time closed-loop tracking method based on a rotating double prism. The method solves the nonlinear and strong coupling relationship among the miss amount, the target position and the prism rotation angle through a decoupling algorithm. The off-target amount fed back by the detector is used to control the prism rotation in real time, so that the target image is always at the center of the detector's field of view. This method can overcome the parameter error of the prism system, and the tracking accuracy is higher; and through the decoupling algorithm, the rotation mode of the prism is optimized, without repeated rotation, and the tracking process is smoother and faster.

Description

A Real-time Closed-Loop Tracking Method Based on Rotating Biprism

technical field

The invention belongs to the field of photoelectric tracking, and relates to a real-time closed-loop tracking method based on a rotating double prism.

Background technique

The photoelectric capture tracking and aiming system uses light waves as the information carrier, has extremely high resolution in the time domain, space domain, and frequency domain, and has strong anti-electromagnetic interference capabilities. Fields such as fire control aiming have increasingly wide applications.

At present, traditional mechanical scanning devices such as gimbals and mirrors are generally used in photoelectric capture tracking and aiming systems. The gimbal can rotate at a large angle, but has a large volume and poor dynamic response capability; the mirror has a fast response speed and high precision, but has a small deflection angle and is more sensitive to mechanical errors.

Based on the beam control mechanism of the rotating double prism (Risley prism), the large-angle deflection of the beam can be realized through the coaxial and independent rotation of the two prisms. It has the characteristics of compact structure, high rigidity and quick response. It is very suitable for airborne, spaceborne and other occasions that require high volume and weight, and because of its quick response, it also has great advantages in tracking fast moving targets.

In the prior art (referring to the patents of Yun Maojin, Zu Jifeng, etc.: CN1256609C and patent: CN2655268), it is proposed to use this structure for beam scanning, and the scanning device and scanning algorithm based on the rotating double prism have been studied, but the provided The apparatus and method are not suitable for object tracking. In the patent CN103631276A, Li Jinying and others proposed a technical method of rotating a double prism for target tracking, which requires high precision of the parameters of the prism system.

Contents of the invention

The purpose of the invention is to overcome the deficiencies of the prior art, and control the rotating double prism to track the target in real time in a closed loop by decoupling the miss amount. It can overcome the parameter error of the prism system and improve the tracking accuracy; and optimize the prism rotation mode to avoid repeated rotation during the tracking process and improve the response speed.

The technical solution of the present invention includes: a real-time closed-loop tracking method based on a rotating double prism. First, the main components of the target tracking device include a first prism 1, a second prism 2, a first motor 3, a second motor A position sensor 5 , a second position sensor 6 , a detector 7 , and a controller 8 . Wherein, two prisms, two motors and detectors are coaxially installed. The first prism 1 and the second prism 2 have the same apex angle and refractive index. The first motor 3 and the second motor 4 are ring torque motors, and the rotors of the two are directly connected to the first prism and the second prism respectively, which saves the intermediate transmission link and has the characteristics of fast response and high rigidity; the first position sensor 5 Measure the rotation angle θ ₁ of the first prism 1 around the rotation axis, and send θ ₁ to the controller 8; the second position sensor 6 measures the rotation angle θ ₂ of the second prism 2 around the rotation axis, and send θ ₂ to the controller 8. The detector 7 can measure the azimuth angle Θ ₀ and the elevation angle Φ ₀ of the imaged point of the target on the detector 7 . The controller 8 receives the position θ ₁ of the first prism, the position θ ₂ of the second prism, the azimuth θ ₀ and the elevation angle Φ ₀ of the imaged point on the detector 7, and the externally given target guidance data azimuth θ ₁ and pitch angle Φ ₁ ; the output voltage signal V ₁ to the first motor 3, the output voltage signal V ₂ to the second motor 4, through the detector closed loop, so that the target imaging is always near the center of the detector field of view, the real-time closed-loop tracking method The process is as follows:

1) The externally given target guidance position is represented by the azimuth angle Θ ₁ and the pitch angle Φ ₁ . The guidance error needs to be less than half of the field of view of the detector 7 .

2) Control the first prism 1 and the second prism 2 according to Θ ₁ and Φ ₁ to point to the target position. At this time, the azimuth Θ ₀ and the elevation angle Φ ₀ of the image point of the target on the detector are measured by the detector 7 .

3) The projection relationship of the image point, the target guidance position and the synthesized target actual position is expressed in the coordinate system Oxy, as shown in Figure 2, where O represents the center point of the detector, and A(Θ ₀ , Φ ₀ ) represents the image point , B(Θ ₁ , Φ ₁ ) represents the target guidance position, C(Θ ₂ , Φ ₂ ) represents the target position synthesized by point A and point B (Θ ₂ represents the azimuth angle, Φ ₂ represents the pitch angle). According to the relationship in Figure 2, there are:

Among them, ΔΘ represents the azimuth angle error of the target, and ΔΦ represents the pitch angle error of the target.

The decoupling algorithm is shown in formula (3):

Among them, θ ₁ and θ ₂ are the current positions of the first prism 1 and the second prism 2; θ ₁ ^* and θ ₂ ^* are the positions to be adjusted of the first prism 1 and the second prism 2; f(△Θ) represents The prism rotation amount corresponding to the azimuth angle error △Θ; f(△Φ) represents the prism rotation amount corresponding to the pitch angle error △Φ.

The specific expressions of f(△Θ) and f(△Φ) are shown in formula (4) and formula (5):

Among them, G _Θ (s) and G _Φ (s) represent the designed control algorithm, which is composed of G _c (s), K _Θ and K _Φ . G _c (s) can be designed according to the traditional controller design method; K _Θ represents the azimuth gain, and K _Φ represents the pitch gain.

4) Control the movement of the first motor 3 and the second motor 4 through the controller 8, so that it drives the first prism 1 and the second prism 2 to rotate to the positions θ ₁ ^* and θ ₂ ^* , and the target will be locked on the detector 7 center of field of view.

Further, through the decoupling algorithm of azimuth error and pitch error, the strong coupling relationship between the amount of miss and the prism rotation position is solved, and the new positions θ ₁ ^* and θ ₂ ^* that the two prisms need to be rotated to are determined, so as to realize Closed-loop tracking of targets.

The advantage of the present invention compared with prior art is:

The present invention performs closed-loop tracking on the target through the amount of detector off-target, overcomes the parameter error of the prism system, and has higher tracking accuracy; and through the decoupling algorithm, the rotation mode of the prism is more optimized without repeated rotation, and the tracking process is smoother. fast.

Description of drawings

Fig. 1 is a device structural diagram of the present invention;

Fig. 2 is the projection relationship of the image point, the target guidance position and the actual target position synthesized;

Fig. 3 is the imaging curve on the detector;

Fig. 4 is the tracking error convergence curve;

Figure 5 is the prism position correction curve.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

First, a tracking device based on a rotating double prism is introduced with reference to FIG. 1 . The main components of the target tracking device are the first prism 1, the second prism 2, the first motor 3, the second motor 4, the first position sensor 5, the second position sensor 6, the detector 7, and the controller 8.

Wherein the vertex angle of the first prism 1 and the second prism 2 is 7.5°, and the refractive index is 1.5;

The first motor 3 and the second motor 4 are ring-shaped torque motors, and the rotors of the two are directly connected to the first prism and the second prism respectively, which saves the intermediate transmission link and has the characteristics of fast response and high rigidity;

The first position sensor 5 and the second position sensor 6 are circular gratings, which have the advantages of high precision and light weight; the first position sensor 5 measures the rotation angle θ ₁ of the first prism 1 around the rotation axis, and sends θ ₁ to the controller 8; The second position sensor 6 measures the rotation angle θ ₂ of the second prism 2 around the axis of rotation, and sends θ ₂ to the controller 8;

The field of view of the detector 7 is set to 0.5°, and the azimuth Θ and the elevation angle Φ of the imaging point of the target on the detector 7 can be measured;

The controller 8 receives the position θ ₁ of the first prism, the position θ ₂ of the second prism, the azimuth θ ₀ and the elevation angle Φ ₀ of the imaged point on the detector 7, and the externally given target guidance data azimuth θ ₁ and pitch angle Φ ₁ ; output voltage signal V ₁ to the first motor 3 , and output voltage signal V ₂ to the second motor 4 .

The process of completing target tracking is as follows:

1) The externally given target guidance position is represented by the azimuth angle Θ ₁ =127.93 ^° and the elevation angle Φ ₁ =1.27 ^° .

2) Control the first prism 1 and the second prism 2 according to Θ ₁ and Φ ₁ to point to the target position. At this time, the azimuth Θ ₀ and the elevation angle Φ ₀ of the imaging point of the target on the detector are measured by the detector 7 .

3) The projection relationship of the image point, the target guidance position and the synthesized target actual position is expressed in the coordinate system Oxy, as shown in Figure 2, where O represents the center point of the detector, and A(Θ ₀ , Φ ₀ ) represents the image point , B(Θ ₁ , Φ ₁ ) represents the target guidance position, C(Θ ₂ , Φ ₂ ) represents the target position synthesized by point A and point B (Θ ₂ represents the azimuth angle, Φ ₂ represents the pitch angle). According to the relationship in Figure 2, there are:

Among them, ΔΘ represents the azimuth angle error of the target, and ΔΦ represents the pitch angle error of the target.

The decoupling algorithm is shown in formula (3):

Among them, θ ₁ and θ ₂ are the current positions of the first prism 1 and the second prism 2; θ ₁ ^* and θ ₂ ^* are the positions to be adjusted of the first prism 1 and the second prism 2; f(△Θ) represents The prism rotation amount corresponding to the azimuth angle error △Θ; f(△Φ) represents the prism rotation amount corresponding to the pitch angle error △Φ.

The specific expressions of f(△Θ) and f(△Φ) are shown in formula (4) and formula (5):

Among them, G _Θ (s) and G _Φ (s) represent the designed control algorithm, which is composed of G _c (s), K _Θ and K _Φ . G _c (s) is designed as a PI controller, K _Θ =2, K _Φ =50.

4) Control the movement of the first motor 3 and the second motor 4 through the controller 8, so that it drives the first prism 1 and the second prism 2 to rotate to the positions θ ₁ ^* and θ ₂ ^* , and the target will be locked on the detector 7 center of field of view.

The closed-loop process is shown in Figure 3-Figure 5. Figure 3 is the imaging curve on the detector; Figure 4 is the tracking error convergence curve; Figure 5 is the prism position correction curve. It can be seen that the initial tracking error is 15.36", and after closing the loop, the tracking error is reduced to 0.26". The position correction amounts of the first prism 1 and the second prism 2 are respectively corrected by 0.2° and 0.1°.

The above is only a specific implementation mode in the present invention, but the protection scope of the present invention is not limited thereto. Anyone familiar with the technology can understand the conceived transformation or replacement within the technical scope disclosed in the present invention. All should be covered within the scope of the present invention.

Claims (1)

1. it is a kind of based on rotation biprism real-time closed-loop tracking, this method utilize based on rotation biprism photoelectricity with Track device, including the first prism, the second prism, first motor, the second motor, first position sensor, second position sensor, Detector and controller, wherein two prisms, two motors and detector are to be co-axially mounted, the first prism and the second prism tool There are identical apex angle and a refractive index, first motor and the second motor are toroidal torque motor, and the rotor of the two is respectively with first Prism and the second prism are connected directly；The rotation angle, θ of the first prism of first position sensor measurement around the shaft₁, and by θ₁It is sent to Controller；The rotation angle, θ of the second prism of second position sensor measurement around the shaft₂, and by θ₂It is sent to controller；Detector can The azimuth Θ of target imaging point on the detector is obtained to measure₀With pitch angle Φ₀, and it is sent to controller, controller Receive the position θ of the first prism₁, the second prism position θ₂, on detector imaging point azimuth Θ₀With pitch angle Φ₀, And external given goal directed data azimuth Θ₁With pitch angle Φ₁, output voltage signal V₁To first motor, output electricity Press signal V₂Target imaging is set to be always positioned at detector field of view immediate vicinity, feature by detector closed loop to the second motor Be: the real-time closed-loop tracking the following steps are included:

1) external given goal directed position, with azimuth Θ₁With pitch angle Φ₁It indicates, vectoring error need to be less than the two of detector / mono- visual field；

2) according to Θ₁And Φ₁The first prism and the second prism are controlled, so that it is directed toward target position, at this point, being obtained by detector measurement To the azimuth Θ of target picture point on the detector₀, pitch angle Φ₀；

3) projection relation of the target actual positions of picture point, goal directed position and synthesis indicates the O point in coordinate system Oxy Indicate detector central point, A (Θ₀,Φ₀) indicate picture point, B (Θ₁,Φ₁) indicate goal directed position, C (Θ₂, Φ₂) indicate by The target position of A point and the synthesis of B point, Θ₂Indicate azimuth, Φ₂It indicates pitch angle, there is following relationship:

Wherein, Δ Θ indicates the azimuth angle error of target, and ΔΦ indicates the pitching angle error of target；

Shown in decoupling algorithm such as formula (3):

Wherein, θ₁, θ₂For the current location of the first prism and the second prism；θ₁ ^*, θ₂ ^*It needs to adjust for the first prism and the second prism Whole position；F (Δ Θ) indicates the corresponding prism rotation amount of azimuth angle error Δ Θ；F (ΔΦ) indicates pitch angle error delta Φ Corresponding prism rotation amount；

F (Δ Θ) and f (ΔΦ) is specifically indicated as shown in formula (4) and formula (5):

Wherein, G_Θ(s) and G_Φ(s) control algolithm for indicating design, by G_c(s)、K_ΘAnd K_ΦIt constitutes, G_c(s) it is designed as PI control Device；K_ΘIndicate azimutal gain, K_ΦIndicate pitching gain；

4) first motor and the second motor movement are controlled by controller, makes it that the first prism and the second prism be driven to be rotated in place Set θ₁ ^*、θ₂ ^*, target will be locked in the field of view center of detector.