High-precision stable tracking method

Abstract

The invention provides a high-precision stable tracking method, and relates to the technical field of photoelectric control, and the method comprises the steps: S1, when a DIRCM obtains an initial position of a target, a position loop is controlled by a cosine trajectory planning controller, and an aiming line is controlled to reach a designated position; s2, the automatic video tracker outputs a target miss distance through full-pixel detection, the target miss distance is compensated by a delay compensator and then input into a coarse tracking controller to obtain a speed loop control quantity, and the speed loop control quantity is input into a speed loop to enable the target to be in a view field; and S3, the automatic video tracker adopts 30% pixel detection to output a target miss distance, the target miss distance is compensated by a delay compensator and then input into a fine tracking controller to obtain a speed loop control quantity, and the speed loop control quantity is input into a speed loop to enable the target to be in the center of the field of view. The method comprises a delay compensation strategy and a variable detector integral time control strategy, and the problems of miss distance output delay and detector integral time are solved respectively.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric control, and in particular provides a high-precision stable tracking method. Background Art

[0002] Directed infrared countermeasures (DIRCM) systems can protect aircraft from attacks by infrared homing guided missiles. The DIRCM stabilized platform usually adopts a frame-mounted reflector configuration with a small external envelope and has pointing capabilities in two axes. DIRCM also has an infrared camera and a jamming laser. Once a target is detected, the reflector is used to control the direction of the optical axis, continuously track the target, and turn on the laser jammer until the infrared guided missile deviates from the aircraft. The infrared camera has a certain integration time and output frame rate. During this process, the aiming line of sight of the stabilized platform is susceptible to the movement of the carrier aircraft. The largest angular movement occurs when the aircraft rolls, pitches or yaws, usually up to 400 degrees / second. Since the DIRCM head is mounted on the outside of the aircraft, the aiming line may be severely affected during the infrared camera integration time. Another major factor in angular movement is aircraft vibration. Therefore, during the detector integration time, if it is not compensated, the aiming point is susceptible to movement. When the target is illuminated by a directional countermeasure system, the problem becomes how to offset the movement of the aircraft.

[0003] The stabilization platform of the directional infrared countermeasure system usually adopts a semi-strapdown stabilization method. The inertial measurement element is installed on the base of the stabilization platform. The measured inertial angular velocity of the carrier and the angular velocity of the frame are used to reconstruct the visual axis motion characteristics. The inertial angular velocity of the visual axis is calculated and used as feedback for the stable control of the visual axis to offset the angular motion of the carrier. The linear motion of the carrier and the motion of the target are mainly offset by the automatic video tracking loop. The automatic video tracker detects the deviation information of the target image in the field of view relative to the visual axis, that is, the target miss amount, which is used as the error control signal of the inertial stabilization platform. After the miss amount is corrected, the gimbal movement is controlled to make the visual axis point to the target, realizing real-time tracking of the target. However, the miss amount output delay and detector integration time in the tracking loop will affect the improvement of the tracking loop control bandwidth and phase margin, and the impact on the tracking loop is the most serious. Summary of the invention

[0004] The purpose of this application is to provide a high-precision stable tracking method to solve the problems of miss-target output delay and detector integration time.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A high-precision stable tracking method, the method comprising:

[0007] S1: When DIRCM obtains the initial position of the target, the position loop is controlled by the cosine trajectory planning controller to control the aiming line to the specified position;

[0008] S2: After the aiming line reaches the designated position, the automatic video tracker uses full pixel detection to output the target miss amount. After the target miss amount is compensated by the delay compensator, it is input into the coarse tracking controller to obtain the speed loop control amount. The speed loop control amount is input into the speed loop to make the target within the field of view.

[0009] S3: After the automatic video tracker captures the target in the field of view, it uses 30% pixel detection to output the target miss amount. After the target miss amount is compensated by the delay compensator, it is input into the precision tracking controller to obtain the speed loop control amount. The speed loop control amount is input into the speed loop to make the target in the center of the field of view.

[0010] The high-precision stable tracking method provided by the present invention also has the following characteristics: the angular frequency ω and the amplitude A of the cosine trajectory planning controller are calculated by the arrival time T.

[0011]

[0012] Among them, θ0 is the initial position of the target.

[0013] The high-precision stable tracking method provided by the present invention also has the following characteristics: after the delay compensator compensates, t k Missing amount at time for:

[0014]

[0015] Among them, θ(t k-1 ) indicates t k-1 Delay measurement at time T ω represents the update period of ω, and n represents [t k ,t k+1 ]The number of updates within a cycle, ω(t k-1 +nT ω ) indicates t k-1 +nT ω The speed of time, represents the estimated angle of θ(t), T θ represents the update period of θ.

[0016] The high-precision stable tracking method provided by the present invention also has the following characteristics: the gain K1 of the coarse tracking controller is

[0017] K1=2π 2 f1 2

[0018] Wherein, f1 is the bandwidth of the coarse tracking controller, and f1 is 1Hz-6Hz.

[0019] The high-precision stable tracking method provided by the present invention also has the following characteristics: the gain K2 of the coarse tracking controller is

[0020] K2=2π 2 f2 2

[0021] Wherein, f2 is the bandwidth of the coarse tracking controller, and f2 is 20Hz-30Hz.

[0022] Beneficial Effects

[0023] The tracking method provided by the present invention includes a delay compensation strategy and a variable detector integration time control strategy, which respectively solve the problem of miss amount output delay and detector integration time. In view of the miss amount output delay problem, the time difference from the infrared imaging moment to the miss amount output moment is calculated through a unified time system, and then the miss amount deviation is estimated according to the current speed for compensation. In view of the lag problem caused by detector integration, all pixels of the detector are integrated in the target search stage, and coarse tracking control is achieved by using a low frame rate and a large field of view. In the target tracking stage, the detector window integration method is used, and fine tracking is achieved by using a relatively high frame rate and a small field of view. Finally, high control bandwidth and high-precision tracking of the target are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a principle block diagram of the automatic video tracking control loop of the prior art;

[0026] Figure 2 A block diagram of the tracking loop compensation principle in the method provided by an embodiment of the present invention;

[0027] Figure 3 This is a block diagram of the DIRCM tracking control system in the method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation methods are not limitations of the present application, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation methods are all within the scope of protection of the present application.

[0029] In the description of the embodiments of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the creation of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the creation of the present application.

[0030] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0031] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of this application can be understood by specific circumstances.

[0032] like Figure 1-3 As shown, an embodiment of the present application provides a high-precision stable tracking method, the method comprising:

[0033] S1: When DIRCM obtains the initial position of the target, the position loop is controlled by the cosine trajectory planning controller to control the aiming line to the specified position;

[0034] S2: After the aiming line reaches the designated position, the automatic video tracker uses full pixel detection to output the target miss amount. After the target miss amount is compensated by the delay compensator, it is input into the coarse tracking controller to obtain the speed loop control amount. The speed loop control amount is input into the speed loop to make the target within the field of view.

[0035] S3: After the automatic video tracker captures the target in the field of view, it uses 30% pixel detection to output the target miss amount. After the target miss amount is compensated by the delay compensator, it is input into the precision tracking controller to obtain the speed loop control amount. The speed loop control amount is input into the speed loop to make the target in the center of the field of view.

[0036] In some embodiments, the angular frequency ω and amplitude A of the cosine trajectory planning controller are calculated from the arrival time T.

[0037]

[0038] Among them, θ0 is the initial position of the target.

[0039] In some embodiments, after the delay compensator compensates, t k Missing amount at time for:

[0040]

[0041] Among them, θ(t k-1 ) indicates t k-1 Delay measurement at time T ω represents the update period of ω, and n represents [t k ,t k+1 ]The number of updates within a cycle, ω(t k-1 +nT ω ) indicates t k-1 +nT ω The speed of time, represents the estimated angle of θ(t), T θ represents the update period of θ.

[0042] In some embodiments, the gain K1 of the coarse tracking controller is

[0043] K1=2π 2 f1 2

[0044] Wherein, f1 is the bandwidth of the coarse tracking controller, and f1 is 1Hz-6Hz.

[0045] In some embodiments, the gain K2 of the coarse tracking controller is

[0046] K2=2π 2 f2 2

[0047] Wherein, f2 is the bandwidth of the coarse tracking controller, and f2 is 20Hz-30Hz.

[0048] like Figure 2 As shown in the figure, it is the principle block diagram of tracking loop compensation, P represents the tracking controller, V represents the stabilization loop, ∫ represents the integral link, Q represents the delay compensator, z -1 represents the delay link, θ r (t) represents the actual target motion position at time t in the continuous domain, θ r (k) represents the actual target motion position at time k in the discrete domain, ω rrepresents the speed control quantity calculated by the tracking controller, ω(t) is the target speed at time t in the continuous domain, ω(k) represents the target speed at time k in the discrete domain, θ(t) is the detected target position at time t in the continuous domain, θ(k) represents the detected target position at time k in the discrete domain, and θ(k-1) represents the detected target position at time k-1 in the discrete domain.

[0049] like Figure 3 As shown in the figure, it is a block diagram of the DIRCM tracking control system. When L1 is turned on, the cosine trajectory planning of the position controller generates a speed command signal; when L2 and K1 are turned on at the same time, the coarse tracking controller of the position controller generates a speed command signal to perform video tracking with a relatively low frame rate; when L3 and K2 are turned on at the same time, the fine tracking controller of the position controller generates a speed command signal.

[0050] In some embodiments, the tracking method is as follows:

[0051] S1: When DIRCM obtains the initial position of the target, the position loop controller switches to L1. At this time, the video tracker is in the disconnected state, and the speed command signal is a steady cosine signal generated by the cosine trajectory planner, which guides the aiming line to the specified position;

[0052] After DIRCM obtains the initial position θ0 of the target, it uses the cosine trajectory planning method to plan the speed input of the stabilization loop to ensure that the initial acceleration and final acceleration of the speed command are both 0. The planned speed command expression is A(1-cosωt). The rotation angle of the frame within the period is θ0, that is, but Among them, the angular frequency ω of cosine trajectory planning is determined by the acceleration α of the frame, that is,

[0053] S2: After the aiming line reaches the specified position, the position loop controller switches to L2, the automatic video tracker switches to K1, and the target position is output at a relatively low frame rate of 60 Hz;

[0054] S3: After the automatic video tracker captures the target, the position loop controller switches to L3, and the automatic video tracker switches to K2, using a relatively high frame rate of 300 Hz to output the target position and obtain high-gain tracking loop control.

[0055] Among them, when the position loop controller switches to L2 and L3, the miss delay compensation is in an effective state.

[0056] In order to reduce the delay effect of the video tracker's miss distance output, the current angle value and velocity integral are used for estimation. The specific calculation is as follows:

[0057] represents the estimated angle of θ(t), which is updated only after the video tracker measures a new angle. k =kT θ , k is an integer, T θ Represents the update period of θ. Estimated value Will be in [t k ,t k+1 ] always maintains a value during the period, which can be expressed as:

[0058]

[0059] Where θ(t k-1 ) indicates t k-1 Delay measurement of time, represents the velocity integral within the full sampling period Tθ, ω(τ) represents the velocity at time τ, and the discrete expression is as follows:

[0060]

[0061] Among them, T ω represents the update period of ω, and n represents [t k ,t k+1 ]The number of updates within the cycle.

[0062] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A high-precision stable tracking method, characterized in that: The method comprises: S1: When DIRCM obtains the initial position of the target, the position loop is controlled by the cosine trajectory planning controller to control the aiming line to the specified position; S2: After the aiming line reaches the designated position, the automatic video tracker uses full pixel detection to output the target miss amount. After the target miss amount is compensated by the delay compensator, it is input into the coarse tracking controller to obtain the speed loop control amount. The speed loop control amount is input into the speed loop to make the target within the field of view. S3: After the automatic video tracker captures the target in the field of view, it uses 30% pixel detection to output the target miss amount. After the target miss amount is compensated by the delay compensator, it is input into the precision tracking controller to obtain the speed loop control amount. The speed loop control amount is input into the speed loop to make the target in the center of the field of view.

2. The high-precision stable tracking method according to claim 1, characterized in that: The angular frequency ω and amplitude A of the cosine trajectory planning controller are calculated from the arrival time T. Among them, θ0 is the initial position of the target.

3. The high-precision stable tracking method according to claim 1, characterized in that: After the delay compensator compensates, t k Missing amount at time for: Among them, θ(t k-1 ) indicates t k-1 Delay measurement at time T ω represents the update period of ω, and n represents [t k ,t k+1 ]The number of updates within a cycle, ω(t k-1 +nT ω ) indicates t k-1 +nT ω The speed of time, represents the estimated angle of θ(t), T θ represents the update period of θ.

4. The high-precision stable tracking method according to claim 1, characterized in that: The gain K1 of the coarse tracking controller is K1=2π 2 f1 2 Wherein, f1 is the bandwidth of the coarse tracking controller, and f1 is 1Hz-6Hz.

5. The high-precision stable tracking method according to claim 1, characterized in that: The gain K2 of the coarse tracking controller is K2=2π 2 f2 2 Wherein, f2 is the bandwidth of the coarse tracking controller, and f2 is 20Hz-30Hz.

Images