Three-cascade signal delay compensation control method and system for ATP turntable tracking

Abstract

The invention discloses a three-cascade signal delay compensation control method and system for ATP turntable tracking, and belongs to the technical field of aircraft monitoring and tracking processing. A position advanced feedback predictor (PAFP) is designed to be connected with a first-order low-pass filter in series, so that a three-cascade control form is formed, and the position advanced feedback predictor (PAFP, Position Advanced Feedback Predictor) is designed to be connected with the first-order low-pass filter in series. A miss distance signal with a delay link firstly passes through a first PAFP, image delay is compensated, an original miss distance signal without a delay link is obtained, the signal is transmitted into a first-order low-pass filter, high-frequency noise is filtered out, at the moment, the first-order low-pass filter will bring phase lag of the signal again, and the signal is transmitted to a second PAFP. Therefore, the signal processed by the first-order low-pass filter is transmitted into the PAFP again for correction compensation, and finally a signal without delay and high-frequency noise is output to a servo control system. Through twice PAFP compensation and once low-pass filtering, the problems of delay and noise are effectively solved, and the servo control precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft monitoring, tracking and processing, and in particular to a three-cascade signal delay compensation control method and system for ATP turntable tracking. Background Art

[0002] With the development of science and technology, UAV technology has become more and more mature, and the demand for monitoring and tracking of UAV flights has also increased accordingly, and the demand for tracking accuracy has also increased accordingly, that is, the demand for servo control accuracy has increased accordingly. In addition to the structure and algorithm of the servo system itself, the factor that affects the servo control performance is the delay of the external input signal. In the optoelectronic tracking system, the input signal of the servo system is the image miss amount, and the collection, analysis, and transmission of the image miss amount data will bring about a certain signal delay, which will greatly affect the response and tracking performance of the servo control system. Most of the existing technologies use Smith predictors, Kalman prediction filters, and The Smith predictor needs to know the system model. For the optoelectronic tracking system, its system model is difficult to obtain accurately, so its prediction ability is limited and the compensation effect is general. Although the Kalman prediction filter has better prediction effect than the Smith predictor, its implementation is more complicated. Although the prediction filter is relatively simple to implement, its prediction effect is very limited and it is only suitable for systems with small delays or low tracking accuracy requirements. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing ATP tracking technology and provide a three-cascade signal delay compensation control method and system for ATP turntable tracking.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] A three-cascade signal delay compensation control method for ATP turntable tracking, the steps comprising:

[0006] S1. Input the image miss distance signal with a delay link into the position advance feedback predictor (PAFP) for the first delay compensation to obtain the original miss distance signal without delay;

[0007] S2. The original miss-target amount signal without delay is input into a first-order low-pass filter to filter out high-frequency noise to obtain a filtered signal;

[0008] S3. Inputting the filtered signal again into the position advance feedback predictor (PAFP) for a second delay compensation to eliminate the phase lag caused by the first-order low-pass filter to obtain a final compensation signal;

[0009] S4. Outputting the final compensation signal to the servo control system.

[0010] Furthermore, in step S1, the position advance feedback predictor performs position compensation by using the difference between the current miss distance and the previous miss distance within the delay time through image delay compensation.

[0011] Furthermore, by obtaining the off-target amount With interval delay time The last off-target value obtained The difference To compensate for the position, the position difference compensation capability is insufficient and there is no adjustment capability. Therefore, a closed-loop controller is introduced for adjustment control and the delay time is set to , then the position compensation difference is:

[0012] ;

[0013] Right now:

[0014] ;

[0015] in, and Delay for The delay phase, is the input value, (here is the definition of the parameter).

[0016] Furthermore, the output value after position compensation is , and its calculation formula is:

[0017] .

[0018] Furthermore, the transfer function in the position compensation process is:

[0019] ;

[0020] If the delay is fully compensated, then ,but:

[0021] .

[0022] The closed-loop controller for:

[0023] .

[0024] Furthermore, in the position advance feedback predictor, by adjusting the delay time To adapt.

[0025] Furthermore, the cut-off frequency of the first-order low-pass filter is selected according to the high-frequency noise type of the image miss-target amount signal.

[0026] Furthermore, the step of determining the cutoff frequency of the first-order low-pass filter includes:

[0027] Performing spectrum analysis on the image miss distance signal to identify the main frequency range of high-frequency noise;

[0028] The cutoff frequency is set to be lower than the lowest frequency of the high frequency noise.

[0029] A three-stage cascade signal delay compensation control system for ATP turntable tracking is provided, comprising:

[0030] A position advance feedback predictor PAFP module, executing steps S1 and S3 of claim 1;

[0031] A low-pass filtering module, executing step S2 of claim 1;

[0032] The output module executes step S4 described in claim 1.

[0033] The beneficial effects of the present invention are:

[0034] (1) It can achieve more accurate tracking of targets such as drones; and achieve good compensation filtering performance under given signal sources, noise, and delay conditions;

[0035] (2) Through two PAFP compensations and one low-pass filtering, the delay and noise problems are effectively solved and the servo control accuracy is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flow chart of the steps of the three-cascade signal delay compensation control method;

[0037] Figure 2 This is the control block diagram of the position advance feedback predictor (PAFP);

[0038] Figure 3 It is a processing flow chart of a three-stage cascade signal delay compensation control system;

[0039] Figure 4 This is a processing structure diagram of this embodiment. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0041] This embodiment designs a position advance feedback predictor (PAFP) in series with a first-order low-pass filter to form a three-cascade control form. The miss amount signal with a delay link first passes through the first PAFP to compensate for the image delay and obtain the original miss amount signal without a delay link. This signal is passed into the first-order low-pass filter to filter out high-frequency noise. At this time, the first-order low-pass filter will bring about a phase lag of the signal again. Therefore, the signal processed by the first-order low-pass filter is passed into the PAFP again for correction and compensation, and finally a signal without delay and high-frequency noise is output to the servo control system. The system processing flow is as follows: Figure 1 shown.

[0042] On this basis, a three-cascade signal delay compensation control method for ATP turntable tracking is provided, and the steps include:

[0043] S1. Input the image miss distance signal with a delay link into the position advance feedback predictor (PAFP) for the first delay compensation to obtain the original miss distance signal without delay;

[0044] S2. The original miss-target amount signal without delay is input into a first-order low-pass filter to filter out high-frequency noise to obtain a filtered signal;

[0045] S3. Inputting the filtered signal again into the position advance feedback predictor (PAFP) for a second delay compensation to eliminate the phase lag caused by the first-order low-pass filter to obtain a final compensation signal;

[0046] S4. Outputting the final compensation signal to the servo control system.

[0047] See also Figure 2 , Position Advance Feedback Predictor (PAFP) Design: Using the current acquisition of miss distance With interval delay time The last off-target value obtained The difference Position compensation is performed, but the simple position difference compensation is not only insufficient in compensation ability, but also has no adjustment ability. Therefore, a closed-loop controller is introduced for adjustment control, and it is assumed that the delay time Known, the controller control block diagram design is as follows Figure 2 shown.

[0048] in, The delay is The delay phase, For the delay time.

[0049] Therefore, the position compensation difference for:

[0050] ;

[0051] Right now:

[0052] ;

[0053] Output for:

[0054] ;

[0055] The system transfer function is obtained through the above formula:

[0056] ;

[0057] If the system delay is fully compensated, then ,Right now:

[0058] ;

[0059] Finally, the closed-loop controller is obtained for:

[0060] .

[0061] Delay time Known, but in practical engineering applications, it is assumed that the delay time It is difficult to know exactly, so the controller uses the adjustment parameter To adapt to different engineering applications. The final control block diagram of PAFP is as follows Figure 2 shown.

[0062] Compensation adjustment parameters The relationship with the PAFP compensation capability is shown in Table 1.

[0063] Table 1 Compensation adjustment parameters Table of relationship with PAFP compensation capacity

[0064]

[0065] Three-stage cascade signal delay compensation control design: In actual engineering applications, the image off-target amount will have a certain amount of high-frequency noise, which needs to be filtered out in engineering applications. However, the filter itself will cause phase lag. If the off-target amount is filtered first and then delay compensation is performed, then when the system delay itself is large, it will cause a greater delay, and the delay compensation may be greatly affected at the maneuvering point. Therefore, in order to avoid this situation, the original off-target amount is first delayed compensated, then filtered, and finally the filtered signal is delayed compensated to eliminate the phase lag effect of the filter, thereby forming a three-stage cascade signal delay compensation control strategy. The system control block diagram is shown below. Figure 3 shown.

[0066] During the experiment, the signal source is given by y=sint, a random noise with an amplitude of 0.01 is introduced, and a delay of 30ms is given. The experimental results are as follows Figure 4 shown.

[0067] Depend on Figure 4 It can be seen that this strategy is not only simple to implement, but also independent of the system model. It has good compensation filtering performance for delayed signals with high-frequency noise, which verifies the feasibility of this control strategy.

[0068] Example 2

[0069] Signal delay compensation in the UAV optoelectronic tracking system. In the UAV optoelectronic tracking system, the image sensor collects the target miss distance signal in real time, but due to the image transmission and processing delay (such as 30ms), the servo control system responds laggingly. At the same time, there is high-frequency interference in the image noise (such as random noise above 100Hz), which affects the tracking accuracy. Delay compensation and noise filtering are achieved through a three-cascade control strategy.

[0070] System configuration 1. Sensor module: CCD camera collects target images in real time and outputs miss distance signal (x(t)). 2. PAFP module: contains two identical position advance feedback predictors (PAFP1 and PAFP2). 3. Low-pass filter module: first-order RC low-pass filter, with the cutoff frequency set to 80Hz. 4. Servo control system: turntable drive unit, receiving the compensated signal (u(t)).

[0071] Parameter setting: Delay time: Initial setting is 30ms ( =0.03s); PAFP adjustment parameters: through experimental setting, k=1.2 is taken to achieve full compensation (refer to Table 1); low-pass filter cutoff frequency: through spectrum analysis, it is determined that the high-frequency noise is mainly distributed in 100Hz~200Hz, so the cutoff frequency is set to 80Hz.

[0072] Implementation steps 1. First delay compensation (S1) Input: Missing amount signal x( ). PAFP1 calculation: Current miss distance: x(t) Last miss distance: x( ) Compensation difference: Δx=x(t)x( )Output: delay-free signal x1(t)=x(t)+k·Δx2. High-frequency noise filtering (S2) Input: x1(t) First-order low-pass filter processing: Transfer function: G_f(s)=1 / ( _fs+1), where _f=1 / (2πf_c)=1 / (2π×80)≈1.99msOutput: Filtered signal x2(t)3. Second delay compensation (S3)Input: x2(t) (phase lag due to filtering)PAFP2 repeats the compensation logic of PAFP1 to eliminate the delay introduced by the filter.Output: Final compensation signal u(t); Servo control (S4)u(t) drives the turntable to track the target in real time.

[0073] Verification process: Test conditions Signal source: y=sin(2π×10t) (10Hz sinusoidal signal); Superimposed noise: Random noise with an amplitude of 0.01 (simulating high-frequency interference); Delay time: 30ms2. Result analysis Comparison of input signal and delayed signal: The phase lag of the delayed signal is about 90° (corresponding to a 30ms delay). The compensated signal u(t) almost coincides with the original input signal y(t), and the phase difference is less than 5°, verifying the delay compensation effect. The noise amplitude dropped from 0.01 to below 0.002, indicating that the filtering is effective.

[0074] Practical application advantages: Strong adaptability: By adjusting the PAFP parameters, it can adapt to different delay times (such as 20ms~50ms); High robustness: No precise system model is required, suitable for UAV tracking in complex environments; Good real-time performance: The three-stage cascade structure has low computational complexity and meets the high bandwidth requirements of the servo system.

[0075] The embodiment demonstrates the specific application of the three-cascade control strategy in the UAV optoelectronic tracking system. Through two PAFP compensations and one low-pass filtering, the delay and noise problems are effectively solved and the servo control accuracy is improved.

[0076] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A three-stage cascade signal delay compensation control method for ATP turntable tracking, characterized in that the steps include: S1. Inputting the image miss amount signal with a delay link into the position advance feedback predictor for the first delay compensation to obtain the original miss amount signal without delay; S2. The original miss-target amount signal without delay is input into a first-order low-pass filter to filter out high-frequency noise to obtain a filtered signal; S3. The filtered signal is input again into the position advance feedback predictor for a second delay compensation to eliminate the phase lag caused by the first-order low-pass filter to obtain a final compensation signal; S4. Outputting the final compensation signal to the servo control system.

2. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 1 is characterized in that: In step S1, the position advance feedback predictor performs position compensation by using the difference between the current miss distance and the previous miss distance within the delay time through image delay compensation.

3. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 2 is characterized in that: Obtain the miss distance and interval delay time through the current The difference between the last off-target value Perform compensation position compensation, adjust and control through closed-loop controller, and set the delay time to , then the position compensation difference is: ； in, and Delay for The delay phase, is the input value.

4. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 3 is characterized in that: The output value after position compensation is , and its calculation formula is: 。 5. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 4 is characterized in that: The transfer function during position compensation is: ； If the delay is fully compensated, then ,but: 。 6. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 4 is characterized in that: In the position advance feedback predictor, by adjusting the delay time To adapt.

7. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 1 is characterized in that: The cut-off frequency of the first-order low-pass filter is selected according to the high-frequency noise type of the image miss-target amount signal.

8. The three-stage cascade signal delay compensation control method for ATP turntable tracking according to claim 1 is characterized in that: The step of determining the cut-off frequency of the first-order low-pass filter comprises: Performing spectrum analysis on the image miss distance signal to identify the main frequency range of high-frequency noise; The cutoff frequency is set to be lower than the lowest frequency of the high frequency noise.

9. A three-stage cascade signal delay compensation control system for ATP turntable tracking, characterized in that: The system comprises: A position advance feedback estimator module, executing steps S1 and S3 of claim 1; A low-pass filtering module, executing step S2 of claim 1; The output module executes step S4 described in claim 1.

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