A laser frequency ambiguity control system and method

Abstract

The application discloses a laser frequency fuzzy control system and method, comprising laser generation modules, ZYNQ modules and laser control modules connected in sequence, wherein the output end of the laser control module is connected with the control end of the laser generation module, and the laser generation module, the ZYNQ module and the laser control module form a closed loop locking circuit; the fuzzy control system and method can realize quick automatic locking and relocking of the difference frequency of the laser generation module based on the ZYNQ module, so that the high-constraint plasma polarization interferometer system can be normally applied to an environment with interference.

Description

Technical Field

[0001] This invention relates to the field of laser frequency control technology, and in particular to a laser frequency fuzzy control system and method. Background Technology

[0002] THz waves refer to electromagnetic radiation with frequencies ranging from 0.1 to 10 THz (wavelengths from 3000 to 30 micrometers). This band lies within a fairly wide electromagnetic radiation region between microwaves and infrared light. This electromagnetic spectrum, encompassing a portion of the millimeter-wave band (approximately 0.1 THz) to the far-infrared region (approximately 25 THz), is crucial in condensed matter physics research because it contains many important energy levels that determine material properties. Other phenomena, such as electron and phonon scattering and various tunneling mechanisms, largely overlap with the THz wave region on either energy or time scales. Furthermore, because the THz band contains the rotational or vibrational energy levels of most molecules, it also has significant applications in security, counter-terrorism, space remote sensing, communications, and medical imaging. The core band of terahertz light (0.5 THz to 3 THz) is also a window for measuring the electron and current densities of fusion plasma using polarization interferometers. THz light detection technology mainly includes: high-power terahertz sources; THz radiation detection technology; terahertz imaging technology; and their applications. One of the most important technologies, and also one of the key technologies that limits the development of terahertz technology, is the development of high-power continuous wave terahertz laser sources.

[0003] High-power continuous-wave terahertz gas lasers are currently the most mature and promising light source in the terahertz band. Carbon dioxide-pumped terahertz lasers, especially carbon dioxide-pumped formic acid lasers with an output wavelength of 432 nm, are extremely suitable light sources for diagnosis using magnetically confined plasma far-infrared laser polarization interferometers. They also have significant application prospects in many other key application areas, such as medical imaging and security inspection imaging.

[0004] In the diagnosis of magnetically confined plasma far-infrared laser polarization interferometer, the three-wave method is widely used due to its high spatiotemporal resolution and strong anti-interference ability. The key factor to ensure the accuracy of the three-wave method diagnosis results is the stability of the difference frequency between the two lasers.

[0005] Among the many applications of lasers, the stability of laser frequency is an extremely important parameter. With the continuous development of laser applications, laser frequency stabilization technology has become an important tool for basic scientific research, and the difference frequency stability of dual lasers is also of paramount importance for three-wave polarization interferometry diagnostic technology.

[0006] However, due to the mechanical vibration of the optical components themselves and the influence of the surrounding magnetic field temperature, the stability of the difference frequency between the two lasers will inevitably be disturbed, making it easy to jump out of the effective frequency locking range. The existence of this loss of locking phenomenon also greatly limits the accuracy of the results data of the high-confinement plasma polarization interferometry diagnostic system. Summary of the Invention

[0007] Based on the technical problems existing in the background technology, the present invention proposes a laser frequency fuzzy control system and method. Based on the ZYNQ module, it can realize the rapid automatic locking of the difference frequency of the laser generation module and the re-locking after loss of lock, so that the high-constraint plasma polarization interferometer system can be used normally in the environment with interference.

[0008] The present invention proposes a laser-based frequency fuzzy control system, comprising a laser generating module, a ZYNQ module, and a laser control module connected in sequence. The output terminal of the laser control module is connected to the control terminal of the laser generating module, and the laser generating module, the ZYNQ module, and the laser control module form a closed-loop locking circuit.

[0009] Furthermore, the laser generating module includes a laser, a mixer, and a signal amplifier;

[0010] A mixer is used to combine the laser beams output from two lasers and output a difference frequency voltage signal.

[0011] The signal amplifier is used to process the received differential frequency voltage signal to obtain a multiplied differential frequency voltage signal, and then sends the amplified differential frequency voltage signal to the input terminal of the ZYNQ module.

[0012] Furthermore, the laser control module includes a voltage reduction module and a laser controller. The voltage reduction module is used to receive the analog signal output by the ZYNQ module, and after reducing the analog signal by several times, it is fed back to the laser through the laser controller.

[0013] Furthermore, the ZYNQ module includes a PL-side module, a PS-side module, a first conversion module, and a second conversion module;

[0014] The first conversion module converts the amplified difference frequency voltage signal output by the signal amplifier into a difference frequency digital signal;

[0015] The PL-side module calculates the frequency value, error signal, and error change signal of the received difference frequency digital signal, determines the locking state of the difference frequency of the dual lasers based on the error signal and error change signal, and automatically locks the laser frequency and automatically controls it after it loses lock based on the locking state.

[0016] The second conversion module converts the digital control signal output from the PL-side module into an analog signal and sends it to the voltage reduction module;

[0017] The PS-side module displays and stores the frequency value, error value, and error change amount output by the PL-side module.

[0018] Furthermore, the PL-side module includes a frequency detection sub-loop module, an error calculation module, an error change calculation module, a fuzzy control PID address generation module, and a fuzzy control PID addressing module;

[0019] The frequency detection sub-circuit module is used to calculate the frequency value of the received amplified difference frequency voltage signal and transmit the frequency value to the error calculation module and the PS side module;

[0020] The error calculation module is used to convert the received frequency values ​​into error values;

[0021] The error change calculation module is used to calculate the error value at different times and obtain the error change.

[0022] The fuzzy control PID address generation module is used to generate the addressing address of the fuzzy PID control quantity based on the error value and the error change, and send the addressing address to the fuzzy control PID addressing module to generate the fuzzy control quantity. The fuzzy control quantity is used to lock the intermediate frequency signal output by the mixer to the target frequency range in real time.

[0023] Furthermore, the frequency detection sub-loop module includes an FFT transformation module, an amplitude calculation module, an amplitude comparison module, and a frequency calculation module;

[0024] The FFT transform module is used to convert the difference frequency digital signal output by the first transformation module into a spectrum signal;

[0025] The amplitude calculation module is used to calculate the spectral amplitude value corresponding to each frequency point of the spectral signal by taking the square root of the sum of the squares of the real part and the imaginary part of the spectral signal.

[0026] The amplitude comparison module is used to sequentially compare the spectral amplitude values ​​of each frequency point and calculate the maximum spectral amplitude value and its corresponding frequency point sequence value.

[0027] The frequency calculation module is used to convert the frequency point sequence value into a frequency value by dividing the product of the frequency point sequence value and the sampling frequency by the number of transformation points.

[0028] Furthermore, the specific process by which the fuzzy control PID address generation module generates the addressing address is as follows:

[0029] Both the error range and the error variation are scaled to the range of -6 to +6, and the range of [-6, +6] is divided into thirteen data intervals with overlap between them, which are referred to as thirteen data maxims.

[0030] A trigonometric function is selected as the membership function for the data interval, and control rules are output based on the error amount, error change amount, and control experience for each data interval.

[0031] Based on the control rules and membership functions, the final control variables are output using the centroid method. The final control quantities are then integrated into a table using the MATLAB Fuzzy toolbox to generate a fuzzy control logic lookup table. This logic lookup table serves as the addressing address generated by the fuzzy control PID address generation module.

[0032] Furthermore, the PS-side module includes an AXI_Lite bus communication module, a timer interrupt module, a DDR memory module, an image generation module, and an LCD display module;

[0033] The AXI_Lite bus communication module sends the received frequency value, error value, error change amount, and error change amount to the timer interrupt module. Through the timer interrupt module's timing operation, at specified intervals, it performs data receiving, storage, and display operations on the data values ​​sent by the AXI_Lite bus communication module.

[0034] The DDR storage module is used to store the data values ​​transmitted by the AXI_Lite bus communication module;

[0035] The image generation module is used to generate interface image data files based on the data values ​​transmitted by the AXI_Lite bus communication module;

[0036] The LCD display module is used to receive the interface image data file generated and the interrupt signal from the timer interrupt module, and displays the data values ​​according to certain rules.

[0037] A laser frequency fuzzy control method is proposed, in which the laser generation module, ZYNQ module, and laser control module form a closed-loop locking circuit. The specific control method is as follows:

[0038] The PL-side module based on the ZYNQ module detects the difference frequency voltage signal output by the laser generation module in real time.

[0039] If the difference frequency voltage signal is in a locked state, the closed-loop locking circuit is in a detection state, the output control quantity is 0, the frequency of the laser generation module is locked at the target frequency, and the frequency change is monitored in real time.

[0040] If the differential frequency voltage signal is in a unlocked state, the closed-loop locking circuit is in a control self-locking state, and the control quantity is output in real time using fuzzy control rules to lock the frequency to the target range in real time.

[0041] During the locked or unlocked state, the PS-side module displays and stores historical and current frequency values ​​as well as output controller quantity information in real time.

[0042] The advantages of the laser frequency fuzzy control system and method provided by this invention are as follows: In this invention, frequency data, error calculation, error change calculation, and control quantity calculation are all performed in the field-programmable gate array (FPGA) module on the PL side, which greatly improves operating efficiency. Furthermore, the first and second conversion modules feature high-speed, high-precision conversion, high control quality, and strong stability. The fuzzy control digital PID has a faster response than general digital PID, resulting in faster control speed and the ability to quickly control the unlocked frequency difference signal. Moreover, key information such as frequency value, error, error change, and control quantity can be monitored in real time via an LCD display, facilitating system debugging and data processing. The system is characterized by its speed, robustness, strong human-machine interaction, and wide applicability. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of the present invention;

[0044] Figure 2 This is a structural diagram of the PL-side module;

[0045] Figure 3 This is a schematic diagram of the PS-side module.

[0046] Among them, 1-laser, 2-mixer, 3-signal amplifier, 4-first conversion module, 5-PL side module, 6-second conversion module, 7-voltage reduction module, and 8-PS side module. Detailed Implementation

[0047] The technical solution of the present invention will now be described in detail through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] like Figures 1 to 3 As shown, the laser frequency fuzzy control system proposed in this invention includes a laser generating module, a ZYNQ module, and a laser control module connected in sequence. The output terminal of the laser control module is connected to the control terminal of the laser generating module, and the laser generating module, the ZYNQ module, and the laser control module form a closed-loop locking circuit.

[0049] Based on the ZYNQ module, the difference frequency of the laser generation module can be quickly and automatically locked and relocked after loss of lock, enabling the high-confinement plasma polarization interferometer system to be used normally in environments with interference.

[0050] The laser generation module, ZYNQ module, and laser control module are detailed below:

[0051] (a1) The laser generation module includes a laser, a mixer, and a signal amplifier;

[0052] A mixer is used to combine the laser beams output from two lasers and output a difference frequency voltage signal.

[0053] The signal amplifier is used to process the received differential frequency voltage signal to obtain a multiplied differential frequency voltage signal, and then sends the amplified differential frequency voltage signal to the input terminal of the ZYNQ module.

[0054] (a2) The laser control module includes a voltage reduction module and a laser controller. The voltage reduction module is used to receive the analog signal output by the ZYNQ module and reduce the analog signal by several times before feeding it back to the laser through the laser controller.

[0055] (a3) The ZYNQ module includes a PL-side module, a PS-side module, a first conversion module, and a second conversion module;

[0056] The first conversion module converts the amplified difference frequency voltage signal output by the signal amplifier into a difference frequency digital signal;

[0057] The PL-side module calculates the frequency value, error signal, and error change signal of the received difference frequency digital signal, determines the locking state of the difference frequency of the dual lasers based on the error signal and error change signal, and automatically locks the laser frequency and automatically controls it after it loses lock based on the locking state.

[0058] The second conversion module converts the digital control signal output by the PL-side module into an analog signal and sends it to the voltage reduction module. Specifically, the second conversion module can be a 6-bit digital-to-analog converter. The frequency error value and the amount of error change are processed by the fuzzy control PID address generation module and the fuzzy control PID addressing module of the PL-side module to obtain the fuzzy control quantity of the digital laser frequency voltage signal. This signal is converted into an analog signal by the second conversion module (DAC) and then applied to the PZT voltage external control port of the laser by the voltage reduction module to achieve stable control of the difference frequency of the two lasers.

[0059] The PS-side module displays and stores the frequency value, error value, and error change amount output by the PL-side module.

[0060] (a4) The PL side module includes a frequency detection sub-loop module, an error calculation module, an error change calculation module, a fuzzy control PID address generation module, and a fuzzy control PID addressing module;

[0061] The frequency detection sub-circuit module is used to calculate the frequency value of the received amplified difference frequency voltage signal and transmit the frequency value to the error calculation module and the PS side module;

[0062] The error calculation module is used to convert the received frequency values ​​into error values;

[0063] The error change calculation module is used to calculate the error value at different times and obtain the error change.

[0064] The fuzzy control PID address generation module is used to generate the addressing address of the fuzzy PID control quantity based on the error value and the error change, and send the addressing address to the fuzzy control PID addressing module to generate the fuzzy control quantity. The fuzzy control quantity is used to lock the intermediate frequency signal output by the mixer to the target frequency range in real time.

[0065] (a5) The frequency detection sub-loop module includes an FFT transformation module, an amplitude calculation module, an amplitude comparison module, and a frequency calculation module;

[0066] The FFT transform module is used to convert the difference frequency digital signal output by the first transformation module into a spectrum signal;

[0067] The amplitude calculation module is used to calculate the spectral amplitude value corresponding to each frequency point of the spectral signal by taking the square root of the sum of the squares of the real part and the imaginary part of the spectral signal.

[0068] The amplitude comparison module is used to sequentially compare the spectral amplitude values ​​of each frequency point and calculate the maximum spectral amplitude value and its corresponding frequency point sequence value.

[0069] The frequency calculation module is used to convert the frequency point sequence value into a frequency value by dividing the product of the frequency point sequence value and the sampling frequency by the number of transformation points.

[0070] Through steps (a1) to (a5), the frequency data information, error calculation, error change calculation, and control quantity calculation in this embodiment are all calculated in the field programmable gate array of the PL side module, which can greatly improve the operating efficiency. Furthermore, the first conversion module and the second conversion module have the characteristics of high-speed and high-precision conversion, high control quality, and strong stability. The fuzzy control digital PID has the characteristics of faster response than general digital PID, fast control speed, and can quickly control the unlocked difference frequency signal. Moreover, the frequency value, error, error change, and control quantity and other key information can be monitored in real time through the LCD display, which is convenient for system debugging and data processing. It has the characteristics of fast control system, strong robustness, strong human-machine interaction, and wide applicability.

[0071] The following is a detailed explanation:

[0072] like Figure 1As shown, the laser frequency fuzzy control system includes a laser 1, a mixer 2, a signal amplifier 3, a first conversion module 4, a PL-side module 5 of the ZYNQ module, a second conversion module 6, a voltage reduction module 7, and a PS-side module 8; both lasers 1 are equipped with piezoelectric ceramics (PZT) for outputting laser light. Laser 1 is a terahertz band laser with high transmittance and low radiation characteristics.

[0073] The lasers output from two lasers 1 are combined and fed into mixer 2 to generate a difference frequency signal. After being amplified by signal amplifier 3, the difference frequency signal enters the first conversion module 4, which outputs the amplified analog difference frequency signal as a 7-bit precision digital signal and inputs it to the PL module 5 of the ZYNQ module. The PL module 5 of the ZYNQ module calculates the frequency value, error signal, and error change based on the input digital signal to determine whether the lock is lost. If the lock is not lost, the control output is 0 and the frequency value is continuously monitored. If the lock is lost, an addressing address is generated according to the fuzzy control rules, and the corresponding fuzzy control quantity is extracted from the ROM module. This fuzzy control quantity is then converted into a high-precision analog signal by the second conversion module 6. After passing through the voltage reduction module 7, the reduced digital quantity is output to the PZT driver. At the same time, the PS-side module 8 also reads the frequency value, error signal, error change, and control quantity generated by the PL module 5 of the ZYNQ module in real time, stores and displays the key information.

[0074] It should be noted that if the detected frequency is within the target locked frequency range, the self-locking circuit is closed, and the frequency value is monitored in real time. If it exceeds the locked frequency range, the self-locking circuit is activated for fuzzy control. The specific process is as follows:

[0075] (b1) The PL side module 5 of the ZYNQ module obtains the current mixer difference frequency value in real time;

[0076] (b2) The PL side module 5 of the ZYNQ module calculates the error value and error change in real time;

[0077] The specific process of frequency calculation based on the difference frequency digital signal output by the first conversion module is as follows: The FFT (Fast Fourier Transformation) IP core in VIVADO software is used to convert the digital signal output by the first conversion module into a spectrum signal, simultaneously generating a corresponding frequency point sequence. Then, amplitude calculation is performed point-by-point based on the frequency point sequence. Amplitude calculation is performed by taking the square root of the sum of the squares of the real and imaginary parts obtained from the FFT transformation. The number of FFT transformation points is set to 4096. During the spectrum conversion process, the digital signal output by the first conversion module needs to be passed through a FIFO IP core with a storage size of 16384 bytes before being input to the FFT for data synchronization. Due to the symmetry of the spectrum, to reduce computation and save board-level resources, after the spectrum conversion is completed, the first half of the spectrum is taken, and a ping-pong FIFO comparison algorithm is used to perform amplitude comparison point-by-point, outputting the maximum amplitude and the corresponding frequency point value. The frequency point is then converted to its frequency value by dividing the product of the frequency point and the sampling frequency by the number of transformation points.

[0078] Based on the frequency set in the program, the error value is obtained by subtracting the frequency value from it, and the error signal is calculated again at the next most recent time point. The difference between the two error signals is then used to calculate the error change.

[0079] (b3) The PL side module 5 of the ZYNQ module accesses and outputs fuzzy control quantities in real time based on the error and the error change;

[0080] The specific process for generating fuzzy control quantities is as follows:

[0081] Both the error range and the error variation are scaled to the range of -6 to +6, and [-6, +6] are set.

[0082] The data range is divided into thirteen data intervals, which overlap with each other.

[0083] Data Analects;

[0084] A trigonometric function is selected as the membership function for the data interval, and control rules are output based on the error amount, error change amount, and control experience for each data interval.

[0085] In this process, the overlapping intervals of [-6 6] are described from smallest to largest, from negative to positive, as NB (large negative), NM (medium negative), NS (small negative), ZO (zero), PS (small positive), PM (medium positive), and PB (large positive). The output control variables are also derived from the corresponding data intervals of these linguistic domains. The control rule, based on experience, can be stated as follows: if the error is large negative and the error change is large positive, then the control variable is large positive. Following this rule, corresponding control variables can be created based on different linguistic domains. Finally, a control lookup table is output.

[0086] Based on the control rules and membership functions, the final control variables are output using the centroid method. The final control quantities are then integrated into a table using the MATLAB fuzzy toolbox, generating a fuzzy control logic lookup table. This lookup table serves as the fuzzy control PID address generation module.

[0087] The address generated by the block;

[0088] The address is sent to the fuzzy control PID addressing module to generate fuzzy control quantity, and the fuzzy control quantity is used to lock the intermediate frequency signal output by the mixer to the target frequency range in real time.

[0089] (b4) The piezoelectric ceramic (PZT) voltage of one of the dual lasers is controlled by the second conversion module 8 according to the feedback control quantity, thereby locking the laser frequency at the target frequency value.

[0090] Automatic locking and automatic control after loss of lock are achieved by (b1) to (b4) of the laser frequency. The automatic control after loss of lock can be achieved by: calculating the error and the amount of error change based on the frequency value, generating fuzzy control quantity through the fuzzy control principle, inputting it into the laser PZT driver through the voltage reduction module, thereby changing the cavity length of the resonant cavity, and monitoring the frequency in real time to observe whether the target frequency range has been reached.

[0091] It is understandable that the specific process of generating fuzzy control change quantities through fuzzy control principles is as follows: The laser system is modeled and simulated using MATLAB data analysis software; a fuzzy control logic lookup table is generated using the fuzzy control toolbox simulation tool built into the MATLAB software; the control quantity in the fuzzy control logic lookup table is appropriately scaled according to the PZT driving voltage range; and the lookup table data is stored in the ROM module of the PL side module 5 of the ZYNQ module. The fuzzy control PID address generation module generates the corresponding addressing address based on the error quantity and error change quantity data, and sends the addressing address to the fuzzy control PID addressing module to generate the fuzzy control quantity, which is then output.

[0092] The fuzzy control logic lookup table is embedded in the ROM module of the PL side module 5 of the ZYNQ module. The specific process is as follows: the fuzzy control logic lookup table data is converted into a text document, and then converted into a COE file using a COE file converter, and loaded into the initialization file location of the ROM module of the PL side module 5 of the ZYNQ module.

[0093] In this embodiment, the PS-side module includes an AXI_Lite bus communication module, a timer interrupt module, a DDR storage module, an image generation module, and an LCD display module;

[0094] The AXI_Lite bus communication module sends the received frequency value, error value, error change amount, and error change amount to the timer interrupt module. Through the timer interrupt module's timing operation, at specified intervals, it performs data receiving, storage, and display operations on the data values ​​sent by the AXI_Lite bus communication module.

[0095] The DDR storage module is used to store the data values ​​transmitted by the AXI_Lite bus communication module;

[0096] The image generation module is used to generate interface image data files based on the data values ​​transmitted by the AXI_Lite bus communication module;

[0097] The LCD display module is used to receive the interface image data file generated and the interrupt signal from the timer interrupt module, and displays the data values ​​according to certain rules.

[0098] The process of generating the interface image data file is understandable: First, the BMP image bitmap file is converted into a binary header file using an image conversion tool. Each data point in the file corresponds to the color data of one pixel, using 16-bit true color conversion with a resolution of 840*480. When the timer interrupt is enabled and the interrupt service function is executed, the designed LCDdisplay function can load the corresponding header file into the LCD display module to display the interface image. The getnum function is used to display the corresponding frequency variable value in the LCD display module. Finally, the LCDRefresh function is added so that the interface data is automatically refreshed every second when the interrupt is enabled, thus completing the interface display function.

[0099] The specific display process of the PS-side module is as follows:

[0100] (c1) The AXI_Lite bus communication module transmits key data to the PS-side module.

[0101] (c2) The PS-side module starts timing the timer interrupt module;

[0102] The timer counts its internal clock at the start of the program. When it reaches the count value of one second, it sends an interrupt request signal to the CPU. The CPU receives the interrupt request signal, agrees to the interrupt, and executes the interrupt internal function, which is the data-related display function and data storage function.

[0103] (c3) The PS-side module completes its timer and reads key data.

[0104] (c4) The PS-side module receives a timer interrupt and completes the key data storage and display functions.

[0105] The frequency, error value, error change, and control data of the PL-side module are transmitted to the PS-side module in real time through the AXI_Lite bus communication module. The frequency of storage and display operations is set through the timer interrupt module. Whenever the timer interrupt is triggered, the PS-side module uses the DDR storage module to record and store the current and historical frequency values, and uses the LCD display module to load the image data information generated by the image generation module in real time, thus completing the entire display and storage process.

[0106] A laser frequency fuzzy control method is proposed, in which the laser generation module, ZYNQ module, and laser control module form a closed-loop locking circuit. The specific control method is as follows:

[0107] S1: The PL-side module based on the ZYNQ module detects the difference frequency voltage signal output by the laser generation module in real time;

[0108] S2: If the difference frequency voltage signal is in a locked state, the closed-loop locking circuit is in a detection state, the output control quantity is 0, the frequency of the laser generation module is locked at the target frequency, and the frequency change is monitored in real time.

[0109] S3: If the differential frequency voltage signal is in a unlocked state, the closed-loop locking circuit is in a control self-locking state, and the control quantity is output in real time using fuzzy control rules to lock the frequency to the target range in real time.

[0110] The specific process of locking the frequency difference between the two lasers within the target frequency range is as follows: real-time acquisition of the mixer frequency analog signal of the current state of the two lasers; conversion of the frequency analog signal into a digital quantity through the first conversion module; real-time detection of the frequency value through the frequency detection sub-loop; calculation of the error and error change based on the frequency by the PL side module and addressing through fuzzy control rules, outputting a fuzzy control quantity; and recalibration of the laser output frequency through the second conversion module based on the fuzzy control quantity.

[0111] S4: During the locked or unlocked state, the PS-side module displays and stores historical and current frequency values ​​as well as output controller quantity information in real time.

[0112] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A laser frequency fuzzy control system, characterized in that, It includes a laser generating module, a ZYNQ module and a laser control module connected in sequence. The output terminal of the laser control module is connected to the control terminal of the laser generating module. The laser generating module, the ZYNQ module and the laser control module form a closed-loop locking circuit. The ZYNQ module includes a PL-side module, a PS-side module, a first conversion module, and a second conversion module; The first conversion module converts the amplified difference frequency voltage signal output by the signal amplifier into a difference frequency digital signal; The PL-side module calculates the frequency value, error signal, and error change signal of the received difference frequency digital signal, determines the locking state of the difference frequency of the dual lasers based on the error signal and error change signal, and automatically locks the laser frequency and automatically controls it after it loses lock based on the locking state. The second conversion module converts the digital control signal output from the PL-side module into an analog signal and sends it to the voltage reduction module; The PS-side module displays and stores the frequency value, error value, and error change amount output by the PL-side module; The PL-side module includes a frequency detection sub-loop module, an error calculation module, an error change calculation module, a fuzzy control PID address generation module, and a fuzzy control PID addressing module. The frequency detection sub-circuit module is used to calculate the frequency value of the received amplified difference frequency voltage signal and transmit the frequency value to the error calculation module and the PS side module; The error calculation module is used to convert the received frequency values ​​into error values; The error change calculation module is used to calculate the error value at different times and obtain the error change. The fuzzy control PID address generation module is used to generate the addressing address of the fuzzy PID control quantity based on the error value and the error change, and send the addressing address to the fuzzy control PID addressing module to generate the fuzzy control quantity. The fuzzy control quantity is used to lock the intermediate frequency signal output by the mixer to the target frequency range in real time.

2. The laser frequency fuzzy control system according to claim 1, characterized in that, The laser generating module includes a laser, a mixer, and a signal amplifier; A mixer is used to combine the laser beams output from two lasers and output a difference frequency voltage signal. The signal amplifier is used to process the received differential frequency voltage signal to obtain a multiplied differential frequency voltage signal, and then sends the amplified differential frequency voltage signal to the input terminal of the ZYNQ module.

3. The laser frequency fuzzy control system according to claim 2, characterized in that, The laser control module includes a voltage reduction module and a laser controller. The voltage reduction module is used to receive the analog signal output by the ZYNQ module, and after reducing the analog signal by several times, it is fed back to the laser through the laser controller.

4. The laser frequency fuzzy control system according to claim 1, characterized in that, The frequency detection sub-loop module includes an FFT transformation module, an amplitude calculation module, an amplitude comparison module, and a frequency calculation module; The FFT transform module is used to convert the difference frequency digital signal output by the first transformation module into a spectrum signal; The amplitude calculation module is used to calculate the spectral amplitude value corresponding to each frequency point of the spectral signal by taking the square root of the sum of the squares of the real part and the imaginary part of the spectral signal. The amplitude comparison module is used to sequentially compare the spectral amplitude values ​​of each frequency point and calculate the maximum spectral amplitude value and its corresponding frequency point sequence value. The frequency calculation module is used to convert the frequency point sequence value into a frequency value by dividing the product of the frequency point sequence value and the sampling frequency by the number of transformation points.

5. The laser frequency fuzzy control system according to claim 1, characterized in that, The specific process by which the fuzzy control PID address generation module generates the addressing address is as follows: Both the error range and the error variation are scaled to the range of -6 to +6, and the range of [-6, +6] is divided into seven data intervals with overlap between them, which serve as seven data quotations. A trigonometric function is selected as the membership function for the data interval, and control rules are output based on the error amount, error change amount, and control experience for each data interval. Based on the control rules and membership functions, the final control variables are output using the centroid method. The final control quantities are then integrated into a table using the MATLAB fuzzy toolbox to generate a fuzzy control logic lookup table. This logic lookup table serves as the addressing address generated by the fuzzy control PID address generation module.

6. The laser frequency fuzzy control system according to claim 1, characterized in that, The PS-side module includes an AXI_Lite bus communication module, a timer interrupt module, a DDR memory module, an image generation module, and an LCD display module; The AXI_Lite bus communication module sends the received frequency value, error value, error change amount, and error change amount to the timer interrupt module. Through the timer interrupt module's timing operation, at specified intervals, it performs data receiving, storage, and display operations on the data values ​​sent by the AXI_Lite bus communication module. The DDR storage module is used to store the data values ​​transmitted by the AXI_Lite bus communication module; The image generation module is used to generate interface image data files based on the data values ​​transmitted by the AXI_Lite bus communication module; The LCD display module is used to receive the interface image data file generated and the interrupt signal from the timer interrupt module, and displays the data values ​​according to certain rules.

7. The control method for the laser frequency fuzzy control system according to claim 1, characterized in that, The laser generation module, ZYNQ module, and laser control module form a closed-loop locking circuit. The specific control method is as follows: The PL-side module based on the ZYNQ module detects the difference frequency voltage signal output by the laser generation module in real time. If the difference frequency voltage signal is in a locked state, the closed-loop locking circuit is in a detection state, the output control quantity is 0, the frequency of the laser generation module is locked at the target frequency, and the frequency change is monitored in real time. If the differential frequency voltage signal is in a unlocked state, the closed-loop locking circuit is in a control self-locking state, and the control quantity is output in real time using fuzzy control rules to lock the frequency to the target range in real time. During the locked or unlocked state, the PS-side module displays and stores historical and current frequency values ​​as well as output controller quantity information in real time.

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