Strong decoupling method for secondary stable tracking of ATP turntable

Abstract

The invention discloses a strong decoupling method for secondary stable tracking of an ATP rotary table, and belongs to the field of ATP tracking control. The strong decoupling method comprises the following steps: acquiring a speed instruction of a control system; acquiring a gyroscope feedback speed including the motion amount of the system and the disturbance amount of the base; based on a first-order inertial link closed-loop model which is obtained through frequency sweeping identification in advance and is used for representing a speed inner loop transfer function of the control system, the speed instruction is used as input of the closed-loop model to generate a simulation motion output quantity; subtracting the simulation motion output quantity from the gyroscope feedback speed to decouple to obtain a base disturbance residual signal; according to the invention, the decoupling error of the traditional scheme is reduced by about 41 times, the secondary tracking precision and anti-disturbance capability of the ATP turntable on the mobile platform to the target are obviously improved, and the technical problem that the disturbance residual error of the base affects fine tracking is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of ATP tracking control, and more particularly to a strong decoupling method for secondary stable tracking on an ATP turntable. Background Technology

[0002] With the development of technology, drone technology is becoming increasingly mature, and the demand for monitoring and tracking drone flights is also increasing. However, the current market-available static ATP (Automatic Tracking Platform) turntables are not very practical for drone monitoring. They not only lack mobility but also have a very limited monitoring range. Therefore, it is necessary to install ATP on unmanned vehicles to achieve highly mobile, large-area monitoring. Simply upgrading ATP to a stable platform can only track drones with relatively close targets. If it is necessary to monitor and track drones with distant targets, a secondary tracking stage is required. However, even after the base disturbance is stabilized by the turntable, the residual base disturbance still has a significant impact on precise tracking. Therefore, a secondary stabilization stage is needed to eliminate the remaining base disturbance residual. The technical challenge lies in how to decouple the base disturbance residual from the gyroscope feedback data. The most popular method is to cancel the speed command with the gyroscope feedback data and then process it through a bandpass filter to obtain an approximate base disturbance residual. However, this method has a large error, especially when the disturbance frequency exceeds the ATP speed bandwidth. Therefore, how to efficiently achieve second-order stable decoupling requires further research. Summary of the Invention

[0003] One of the objectives of this invention is to provide a strong decoupling method for secondary stable tracking of ATP turntables, in order to solve the problem in the prior art that the ATP turntable installed on the mobile platform has insufficient accuracy and poor stability when performing secondary tracking of the target due to the difficulty in effectively separating the residual of the base disturbance.

[0004] This invention is achieved through the following technical solution: a strong decoupling method for secondary stable tracking on an ATP turntable, the strong decoupling method comprising:

[0005] Obtain the speed command from the control system;

[0006] Obtain the gyroscope feedback speed, which includes the system's own motion and the base disturbance.

[0007] Based on a first-order inertial loop closed-loop model that is pre-identified through frequency sweeping and used to characterize the speed inner loop transfer function of the control system, the speed command is used as the input of the closed-loop model to generate simulated motion output.

[0008] The analog motion output is subtracted from the gyroscope feedback velocity to obtain a base disturbance residual signal for decoupling.

[0009] Furthermore, the strong decoupling method also includes:

[0010] The base disturbance residual signal is subjected to bandpass filtering to remove residual low-frequency motion and high-frequency noise, resulting in a filtered disturbance signal.

[0011] The filtered disturbance signal is input into the fast-response mechanism for secondary stabilization control.

[0012] Furthermore, the speed command is a sinusoidal signal.

[0013] Furthermore, the first-order inertial element closed-loop model includes:

[0014] The system amplification factor of the first-order inertial element is determined based on its frequency sweep characteristics in the low-frequency band.

[0015] The time constant of the first-order inertial element is calculated and determined based on the speed loop cutoff frequency of the control system and the system amplification factor.

[0016] Furthermore, the closed-loop model of the first-order inertial element can be expressed by the following equation:

[0017] ,

[0018] in, This is the system amplification factor of the inertial element, representing the system's response gain to speed commands in a steady state; This is a time constant, reflecting the speed of the system response, that is, the time required for the system to reach a stable output. As a dynamic input variable, it represents the various dynamic challenges of this system.

[0019] Furthermore, the bandpass filtering process is implemented by connecting a high-pass filter and a low-pass filter in series.

[0020] Furthermore, the high-pass filter is used to filter out residual low-frequency motion in the base disturbance residual signal.

[0021] Furthermore, the low-pass filter is used to filter out high-frequency noise that exceeds the frequency range of the frequency sweep identification.

[0022] Furthermore, the cutoff frequency of the high-pass filter is lower than the cutoff frequency of the low-pass filter.

[0023] Furthermore, the transfer function of the bandpass filtering process can be expressed as follows:

[0024] ,

[0025] in, This is the low-pass filter section, and its cutoff frequency is... This is used to filter out noise above this frequency; This is the high-pass filter section, and its cutoff frequency is... This is used to filter out residual motion at frequencies below this range. It should be noted that in order to form an effective passband, the following conditions must be met. The conditions are as follows. By carefully designing these two cutoff frequencies, the disturbance signal can be precisely purified from noise and motion residue, and finally sent to actuators such as fast reflectors for secondary stabilization compensation.

[0026] Furthermore, the measurement bandwidth of the gyroscope is higher than the speed inner loop bandwidth of the control system.

[0027] Furthermore, the control system is an ATP turntable system.

[0028] Furthermore, the base disturbance is a periodic disturbance signal.

[0029] Another aspect of the present invention provides a strongly decoupled system with second-order stability for a control system, the strongly decoupled system comprising:

[0030] processor;

[0031] The memory stores a computer program that, when executed by a processor, implements the secondary stability strong decoupling method for a control system as described in any one of claims 1 to 9.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] This invention constructs a closed-loop model of the system's inner velocity loop through frequency sweep identification, achieving mechanistic separation between motion command response and base disturbance signal. By employing the difference calculation between the model prediction output and the gyroscope's measured data, the decoupling error approaches zero under the condition of using a high-bandwidth gyroscope, overcoming the technical bottleneck of performance degradation of traditional cancellation methods beyond the system bandwidth. A bandpass filter, composed of a high-pass filter and a low-pass filter connected in series, effectively filters out low-frequency model error residues and high-frequency measurement noise from the residual signal, ensuring both the accuracy of disturbance extraction and system stability. Finally, the purified disturbance signal is fed forward to the fast-reflecting mirror control loop, achieving high-precision dynamic compensation for remaining disturbances. This invention reduces the maximum decoupling error from 0.0089 rad / s in the traditional scheme to 0.000212 rad / s, a performance improvement of 41 times, significantly enhancing the secondary tracking accuracy and anti-disturbance capability of the ATP turntable on the moving platform, effectively solving the technical problem of base disturbance residuals affecting precise tracking. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0035] Figure 1 This invention provides a general architecture block diagram of a strongly decoupled method for secondary stable tracking on an ATP turntable.

[0036] Figure 2 This is a block diagram of the tidal strong decoupling control part in this invention.

[0037] Figure 3 This is a complete control block diagram of the bistable strong decoupling in this invention.

[0038] Figure 4 The results are experimental comparisons of the bistable strong decoupling error in this invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Example 1

[0041] Figure 1 The overall architecture block diagram of the scheme in this embodiment is shown. This invention proposes a strong decoupling method for secondary stabilization tracking on an ATP turntable. This method achieves strong decoupling of secondary stabilization by designing a strategy to eliminate the tracking and stabilization models. First, the system is placed on a stationary platform, and the inner-loop closed-loop model of the system velocity is identified by frequency sweeping. Second, the issued velocity command is input into this model, and the model output is eliminated from the gyroscope data. Finally, the residual is passed through a low-pass filter to achieve strong decoupling, and the data is finally fed into a fast-reaction circuit for secondary stabilization. Specifically, this strong decoupling control method for secondary stabilization can be constructed through the following steps:

[0042] Step 1: Construct a motion and disturbance separation framework based on model compensation.

[0043] To achieve high-precision secondary stabilization, the primary challenge lies in accurately separating the system's own motion from the disturbances introduced by the external environment. In traditional methods, gyroscopes measure a mixture of these two signals, making them difficult to distinguish. To address this issue, this embodiment employs a tracking and stabilization model to eliminate these disturbances.

[0044] First, accurately identify the dynamic response model of the system itself; then, use this model to predict the theoretical motion output of the system under a given speed command in real time; finally, subtract this theoretical prediction value from the actual measurement data of the gyroscope, thereby canceling out the component of the command motion, so that the residual signal mainly reflects the external disturbance.

[0045] Specifically, to ensure both the real-time performance and efficiency of computation while maintaining the key characteristics of the system, the closed-loop response characteristics of the velocity inner loop of an inertial system can be reasonably simplified and approximated. By treating it as an equivalent first-order inertial element, the core characteristics of the system's response delay and gain can be captured, while avoiding the identification difficulties and computational burden caused by complex high-order models. This model accurately describes the dynamic process from the input velocity command to the system generating an actual angular velocity response.

[0046] For example, in this embodiment, the system velocity inner-loop closed-loop model can be approximately equivalently obtained by the following formula:

[0047]

[0048] in, This is the amplification factor of the inertial element, representing the system's response gain to speed commands in a steady state; It is a time constant, reflecting the speed of the system response, that is, the time required for the system to reach a stable output.

[0049] It should be noted that, in order to obtain the key parameters in the above model ( and (This can be identified by performing a frequency sweep test on a static platform.)

[0050] First, by analyzing the system's response characteristics in the low-frequency range, its amplification factor can be determined. Subsequently, according to control theory, the -3dB cutoff frequency of the system model is... There is a clear mathematical relationship between it and the model parameters.

[0051] For example, in this embodiment, the cutoff frequency The relationship with the model parameters can be calculated using the following formula:

[0052]

[0053] in, The unit is imaginary. In practical engineering applications, because the velocity loop bandwidth (typically 15Hz~30Hz) of inertial systems like ATP turntables is not high compared to high-frequency signals, its main operating frequency band... The condition usually holds true. Based on this premise, the above equation can be approximately simplified, thus establishing a more direct relationship between the cutoff frequency and the model parameters.

[0054] For example, in this embodiment, the above formula can be simplified to:

[0055] ,

[0056] The relationship between the two is as follows:

[0057]

[0058] Using this relationship, the cutoff frequency of the system can be measured through a frequency sweep experiment. Then, the time constant can be directly solved. At this point, the identification of the entire system model is complete.

[0059] Step 2: After establishing the system dynamic response model, a framework separating motion and disturbance can be constructed. This is done by using velocity commands... Simultaneously input into the actual system and the mathematical model we identified In this process, the model output is subtracted from the actual measurement value of the gyroscope, which theoretically eliminates the influence of the command motion and extracts the disturbance of the base.

[0060] For example, in this embodiment, the base disturbance residual can be calculated using the following formula:

[0061]

[0062] in, This is the true closed-loop transfer function of the system's inner velocity loop; This is the transfer function of the gyroscope; For the Laplace transform of the base perturbation; The Laplace transform of the velocity input.

[0063] It should be noted that in an ideal system, if we can perfectly identify the system model, that is... Furthermore, the selected gyroscope can achieve perfect measurement with no delay and no distortion, that is... Then the above residual will degenerate into:

[0064]

[0065] From the above equation, we can see that the residual signal at this time... That is, a pure base disturbance signal. This indicates that the system's commanded motion is completely decoupled from external disturbances. However, in practical engineering applications, model identification always contains errors, and gyroscopes also have bandwidth and latency limitations, so this ideal state cannot be fully achieved. The decoupling errors mainly stem from the inaccuracy of model identification and the limitations of the gyroscope's dynamic characteristics.

[0066] For example, in this embodiment, the actual decoupling error err can be evaluated by the following formula:

[0067]

[0068] Due to the model Through the actual system The results were obtained through frequency sweeping identification; the two frequencies are highly similar within the effective frequency band. Therefore, the second term in the above formula... This will be a small quantity, and the error is mainly determined by the first term. Therefore, the decoupling error can be approximated as:

[0069]

[0070] The above equation clearly points out the key to improving decoupling accuracy: in order to make the error err approach zero, the transfer function of the gyroscope needs to be optimized. The system should aim to achieve a value as close to 1 as possible within its operating frequency band. Physically, this means selecting a high-performance gyroscope with a measurement bandwidth significantly higher than the system's velocity loop bandwidth. When this condition is met, the model compensation method can effectively achieve the goal of strong decoupling and quadratic stability.

[0071] Step 3: Design a bandpass filter for signal purification.

[0072] After initially separating the disturbance signal through model compensation, the resulting residual signal is not completely pure. On the one hand, since model identification cannot cover all frequencies, model mismatch outside the identification frequency band may introduce high-frequency noise; on the other hand, small model errors or sensor drift in the low-frequency band may still cause some motion command energy to leak into the residual signal.

[0073] To solve the above problems, the residual signal needs to be further filtered in order to extract the most critical disturbance frequency band.

[0074] Specifically, in this embodiment, two objectives are achieved: filtering out residual low-frequency motion and suppressing high-frequency noise. To filter out low-frequency components, a high-pass filter is needed; to suppress high-frequency noise, a low-pass filter is required. By cascading these two filters, a band-pass filter is formed, which allows only signals within a specific frequency range to pass through. This range is the core frequency band that best represents the actual disturbance.

[0075] For example, in this embodiment, the bandpass filter can be designed by connecting a low-pass stage and a high-pass stage in series, and its transfer function can be expressed as follows:

[0076]

[0077] in, This is the low-pass filter section, and its cutoff frequency is... This is used to filter out noise above this frequency; This is the high-pass filter section, and its cutoff frequency is... This is used to filter out residual motion at frequencies below this range. It should be noted that in order to form an effective passband, the following conditions must be met. The conditions are as follows. By carefully designing these two cutoff frequencies, the disturbance signal can be precisely purified from noise and motion residue, and finally sent to actuators such as fast reflectors for secondary stabilization compensation.

[0078] Experimental example:

[0079] In this experimental example, according to the method in Example 1, the given speed command is as follows: Given the disturbance quantity is And random noise with an amplitude of 0.0001 (in rad / s) was introduced to obtain the final experimental results as follows. Figure 4 As shown. By Figure 4 As can be seen, under stable system conditions, the maximum error after residual decoupling in this invention is 0.000212 rad / s, while the maximum error after residual decoupling in the traditional scheme is 0.0089 rad / s. The performance of this invention is nearly 41 times better than that of the traditional scheme, effectively verifying the effectiveness and feasibility of this control strategy.

[0080] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A strong decoupling method for ATP turntable secondary stable tracking, characterized in that, The strong decoupling method includes: Obtain the speed command from the control system; Obtain the gyroscope feedback speed, which includes the system's own motion and the base disturbance. Based on a first-order inertial loop closed-loop model that is pre-identified through frequency sweeping and used to characterize the speed inner loop transfer function of the control system, the speed command is used as the input of the closed-loop model to generate simulated motion output. The analog motion output is subtracted from the gyroscope feedback velocity to obtain a base disturbance residual signal for decoupling.

2. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 1, characterized in that, The strong decoupling method further includes: The base disturbance residual signal is subjected to bandpass filtering to remove residual low-frequency motion and high-frequency noise, resulting in a filtered disturbance signal. The filtered disturbance signal is input into the fast-response mechanism for secondary stabilization control.

3. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 1 or 2, characterized in that, The first-order inertial element closed-loop model includes: The system amplification factor of the first-order inertial element is determined based on its frequency sweep characteristics in the low-frequency band. The time constant of the first-order inertial element is calculated and determined based on the speed loop cutoff frequency of the control system and the system amplification factor.

4. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 2, characterized in that, The bandpass filtering process is implemented by connecting a high-pass filter and a low-pass filter in series.

5. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 4, characterized in that, The high-pass filter is used to filter out the residual low-frequency motion in the base disturbance residual signal.

6. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 4, characterized in that, The function of the low-pass filter is to filter out high-frequency noise that exceeds the frequency range of the frequency sweep identification.

7. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 1, characterized in that, The measurement bandwidth of the gyroscope is higher than the speed inner loop bandwidth of the control system.

8. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 1, characterized in that, The control system is an ATP turntable system.

9. The strongly decoupling method for secondary stable tracking on an ATP turntable according to claim 1, characterized in that, The base disturbance is a periodic disturbance signal.

10. A strongly decoupled system with second-order stability for a control system, characterized in that, The strongly decoupling system includes: processor; The memory stores a computer program that, when executed by a processor, implements the secondary stability strong decoupling method for a control system as described in any one of claims 1 to 9.

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