Bidirectional illumination alignment control methods, systems, and media for MEMS optical engines

Abstract

This invention discloses a bidirectional light alignment control method for MEMS optomechanical systems, comprising the following steps: using MEMS closed-loop phase-locked control to track the MEMS resonant frequency in real time via MEMS driving frequency; and using laser emission delay correction to compensate for bidirectional stripe misalignment caused by the deviation between the driving frequency and the resonant frequency. This invention can solve the bidirectional alignment problem of structured light when driving MEMS at the resonant frequency by coordinating MEMS closed-loop phase-locked control and laser emission delay correction, combined with precise driving of the DDS module and high-precision processing of the piezoresistive signal. This ensures high frame rate while avoiding optical power waste, significantly improving light energy utilization and 3D imaging quality.

Description

Technical Field

[0001] This invention relates to the field of 3D structured light imaging and measurement technology, and in particular to a bidirectional illumination alignment control method, system and medium for MEMS optomechanics. Background Technology

[0002] Currently, the imaging principle of 3D structure cameras and 3D scanners is to project structured light stripes through a MEMS optomechanical system. The camera then uses the curvature of the stripes to calculate the surface unevenness of the object being measured. The stability, clarity, and brightness of the stripes projected by the MEMS optomechanical system directly affect the imaging quality and the accuracy of the backend calculations. The working principle of the MEMS optomechanical system is to convert a point source laser into a one-dimensional line laser. Under the action of a driving signal, the MEMS coil drives the mirror to deflect, thereby achieving two-dimensional imaging plane scanning. The deflection angle is combined to control the brightness of the laser to form striped structured light. The driving method is divided into linear driving and resonant driving. The lighting method is divided into unidirectional lighting (lighting only in a single swing direction, easy to align stripes but low laser utilization) and bidirectional lighting (light is emitted in both directions of swing, high output power but stripes are prone to misalignment when the phase changes).

[0003] The relevant existing technologies mainly include the following solutions:

[0004] (1) Linear drive scheme: Driven by a fixed frequency signal far below the MEMS resonant frequency, the phase difference between the drive signal and the deflection angle is almost zero, which is convenient for bidirectional lighting, but there are obvious defects, such as low imaging refresh rate (difficult to meet the sub-millisecond projection requirements of high-speed scanners), requiring a larger drive current (high requirements for the current bearing capacity of hardware circuits and MEMS coils), and being sensitive to drive signal interference and noise (easily leading to abnormal MEMS motion).

[0005] (2) Resonant drive scheme: driven by the MEMS resonant frequency signal, only a small drive current is required, and the MEMS itself can filter out interference noise of non-resonant frequency, reducing the hardware circuit requirements. However, the MEMS is sensitive to temperature, and laser irradiation will cause its resonant frequency to change and the phase difference to change. Using bidirectional lighting will cause the stripes to be misaligned and the image to be blurred. Only unidirectional lighting can be selected, and the utilization rate of the laser is limited.

[0006] In summary, both existing driving schemes have shortcomings: linear driving, while adaptable to bidirectional lighting, struggles to meet requirements in terms of refresh rate and hardware compatibility; resonant driving, while offering advantages in low power consumption and anti-interference, is affected by temperature and cannot achieve stable bidirectional lighting, resulting in low laser utilization. Neither can simultaneously meet the comprehensive requirements of 3D imaging for refresh rate, stripe clarity, hardware cost, and laser utilization, leaving room for optimization. Summary of the Invention

[0007] The purpose of this invention is to provide a bidirectional illumination alignment control method, system, and medium for MEMS optomechanics, thereby solving all or one of the aforementioned problems in the prior art.

[0008] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0009] On one hand, the present invention provides a bidirectional illumination alignment control method for MEMS optomechanics, comprising the following steps:

[0010] In response to MEMS closed-loop phase-locked control operation:

[0011] Control the MEMS driving frequency to track the MEMS resonant frequency in real time;

[0012] In response to laser emission delay correction operation:

[0013] Compensation for bidirectional stripe misalignment caused by the deviation between the driving frequency and the resonant frequency.

[0014] As an improved solution, the MEMS closed-loop phase-locked control operation further includes:

[0015] Acquire the piezoresistive feedback signal of the MEMS and detect the phase difference between the piezoresistive feedback signal and the MEMS driving signal;

[0016] Based on the correspondence between the phase difference and the resonant frequency of the MEMS and the frequency of the drive signal, the frequency control word of the drive signal generation unit is adjusted, and the frequency of the drive signal is controlled to track the change of the resonant frequency by adjusting the frequency control word.

[0017] As an improved approach, the MEMS drive signal is generated based on a DDS module;

[0018] The DDS module generates a phase signal based on the system clock accumulated frequency control word, and outputs a digital sine signal through the high-order address mapping of the phase signal. After DA conversion and low-pass filtering, the MEMS drive signal is obtained.

[0019] As an improved solution, the acquisition of the piezoresistive feedback signal from the MEMS further includes:

[0020] The analog feedback signal output by the MEMS piezoresistive detection circuit is acquired by the AD sampling unit and converted into a digital feedback signal.

[0021] The digital feedback signal is sequentially processed by low-pass filtering, bias removal, linear interpolation, and zero-crossing point determination to extract the zero-crossing point position of the MEMS deflection angle and generate a phase feedback pulse signal with the same frequency as the MEMS drive signal and a duty cycle of 50%.

[0022] As an improved solution, the laser emission delay correction operation further includes:

[0023] In the current MEMS oscillation cycle, the laser emission delay of the current MEMS oscillation cycle is corrected by using the actual phase difference of the previous oscillation cycle, thereby controlling the phase of the laser emission to match the phase of the MEMS deflection angle.

[0024] As an improved approach, the actual phase difference is the phase difference between the driving signal phase calculated during the MEMS closed-loop phase-locked control process in the current MEMS oscillation period and the MEMS deflection angle phase.

[0025] As an improved solution, adjusting the frequency control word of the drive signal generation unit based on the correspondence between the phase difference and the resonant frequency of the MEMS and the drive signal frequency further includes:

[0026] When the frequency of the driving signal is less than the resonant frequency, the phase difference is between -90° and 0, and the frequency control word is increased;

[0027] When the frequency of the driving signal is less than the resonant frequency, the phase difference is equal to -90°, and the current frequency control word is maintained;

[0028] When the frequency of the driving signal is greater than the resonant frequency, the phase difference is between -180° and -90°, and the frequency control word is reduced.

[0029] As an improved solution, the output frequency of the DDS module satisfies a first formula, which is:

[0030] f o =(F clk / 2^N)*F w ;

[0031] The frequency resolution of the DDS module satisfies the second formula, which is:

[0032] △f=F clk / 2^N;

[0033] In the first formula and the second formula, f o F is the drive signal frequency, Δf is the frequency resolution of the DDS module, and F clk The master clock frequency, N is the phase signal bit width, F w This is the frequency control word.

[0034] On the other hand, the present invention also provides a bidirectional illumination alignment control system for a MEMS optomechanism, comprising:

[0035] The closed-loop phase-locked control module is used to perform closed-loop phase-locked control of the MEMS and track the MEMS resonant frequency of the MEMS drive frequency in real time.

[0036] The laser emission delay correction module is used to perform laser emission delay correction to compensate for the misalignment of bidirectional stripes caused by the deviation between the driving frequency and the resonant frequency.

[0037] On the other hand, the present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the bidirectional illumination alignment control method of the MEMS optomechanism.

[0038] The beneficial effects of the technical solution of this invention are:

[0039] 1. The bidirectional light alignment control method of MEMS optomechanic described in this invention can solve the problem of bidirectional alignment of structured light when driving MEMS with resonant frequency by coordinating MEMS closed-loop phase-locked control and laser light output delay correction, combined with DDS module precise driving and piezoresistive signal high-precision processing. This ensures high frame rate while avoiding light power waste and significantly improves light energy utilization and 3D imaging quality.

[0040] 2. The bidirectional illumination alignment control system of the MEMS optomechanism described in this invention can realize the bidirectional illumination alignment control method of the MEMS optomechanism described in this invention through the mutual cooperation between system modules.

[0041] 3. The computer-readable storage medium of the present invention can enable the guidance system module to cooperate and thereby realize the bidirectional illumination alignment control method of the MEMS optomechanism of the present invention. The computer-readable storage medium of the present invention effectively improves the operability of the bidirectional illumination alignment control method of the MEMS optomechanism. Attached Figure Description

[0042] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating the bidirectional illumination alignment control method for the MEMS optomechanism described in Embodiment 1 of the present invention.

[0044] Figure 2 This is a schematic diagram of the logic flow of the bidirectional illumination alignment control method of the MEMS optomechanism described in Embodiment 1 of the present invention;

[0045] Figure 3 This is a schematic diagram of three possible phase relationships between the MEMS driving signal and the resonant frequency in the bidirectional illumination alignment control method of the MEMS optomechanism described in Embodiment 1 of the present invention.

[0046] Figure 4 This is a schematic diagram showing the relationship between the MEMS deflection phase and the laser beam-emitting system phase under ideal conditions in the bidirectional beam-emitting alignment control method of the MEMS optomechanism described in Embodiment 1 of the present invention.

[0047] Figure 5 This is a schematic diagram of the final imaging effect of the bidirectional illumination alignment control method of the MEMS optomechanism described in Embodiment 1 of the present invention;

[0048] Figure 6 This is a schematic diagram of the architecture of the bidirectional illumination alignment control system of the MEMS optomechanism described in Embodiment 2 of the present invention. Detailed Implementation

[0049] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that the embodiments described in this invention are only some embodiments of this invention, not all embodiments; based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0051] The terms "first," "second," etc., used in this specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0052] In the description of this invention, it should be noted that:

[0053] MEMS stands for Micro-Electro-Mechanical System.

[0054] The MEMS opto-mechanics is a structured light pattern projection product composed of MEMS as the core component, together with an electromagnetic base, a laser, and an optical lens;

[0055] The DAC is a digital-to-analog conversion chip;

[0056] The ADC is an analog-to-digital conversion chip;

[0057] The DDS is a digital frequency synthesizer, which is a common method for generating sine waves in a digital manner

[0058] The FPGA is a digital processing chip, and the digital part of the control method introduced in this invention runs in the FPGA.

[0059] Embodiment 1. This embodiment provides a two-way light projection alignment control method for the MEMS opto-mechanics. Through the collaborative scheme of MEMS closed-loop phase-locked control + laser light output delay correction, it solves the two-way light projection alignment problem of the MEMS opto-mechanics under the drive of the resonant frequency, and at the same time meets the requirements of high frame rate and high light energy utilization rate. As Figures 1-5 shown, this method is realized based on the mutual cooperation among the phase-locked control logic module, the MEMS drive signal generation module (DDS module), the MEMS piezoresistive feedback signal processing module, and the light projection control logic module. The specific functions and cooperation logic of the above modules are as follows:

[0060] (1) The phase-locked control logic module, as the core control unit, is used to detect the phase difference between the MEMS drive signal and the actual deflection angle of the MEMS in real time. According to the corresponding relationship between the phase difference and the MEMS resonant frequency, it dynamically adjusts the frequency control word of the DDS module to make the drive signal frequency track the change of the MEMS resonant frequency and maintain the phase stability of the two, providing a basic support for two-way light projection alignment, including:

[0061] Phase difference detection operation: Taking the pulse signal output by the MEMS piezoresistive feedback signal processing module as the phase reference (the rising edge of this pulse signal corresponds to the MEMS deflection phase of 0°, and the falling edge corresponds to 180°), by comparing the phase relationship between this pulse signal and the drive signal output by the DDS module, the phase difference △phase between the actual deflection angle of the MEMS and the drive signal is calculated;

[0062] Frequency adjustment operation: Preset the MEMS resonant frequency as f0 and the drive signal frequency as f. According to the value range of △phase, as Figure 3 shown, three scenarios of frequency closed-loop adjustment are realized:

[0063] (i) When f < f0, △phase satisfies -90° < △phase < 0 (as Figure 3The phase of the particle displacement lags behind the phase of the driving signal by ΔphaseA (Curve A). At this time, the phase-locked loop control logic module outputs a frequency control word increment instruction to increase the frequency control word value of the DDS module, thereby increasing the frequency f of the driving signal and reducing the deviation from f0.

[0064] (ii) When f = f0, Δphase = -90° (e.g.) Figure 3 The middle curve (B), that is, the phase of the particle displacement lags behind the phase of the driving signal △phaseB(-90°): at this time, the driving signal is perfectly matched with the resonant frequency, the phase relationship is stable, the phase-locked control logic module maintains the current frequency control word unchanged, and no adjustment action is required;

[0065] (iii) When f>f0, Δphase satisfies -180°<Δphase<-90° (e.g. Figure 3 The phase of the particle displacement lags behind the phase of the driving signal by ΔphaseC (C-curve C). At this time, the phase-locked loop control logic module outputs a frequency control word decrement instruction to reduce the frequency control word value of the DDS module, thereby reducing the driving signal frequency f until it matches f0.

[0066] It should be noted that the necessary conditions for the phase-locked control logic module to execute the above logic are: having a high-precision phase difference detection capability between the drive signal and the piezoresistive feedback signal (detection error ±0.05°); and the DDS module supporting adjustable frequency control words to ensure that the drive frequency can be corrected in real time.

[0067] (II) The MEMS drive signal generation module (DDS module) employs digital frequency synthesis technology and is composed of a phase accumulator, a sine lookup table (LUT), a DA conversion unit, and a low-pass filter unit cascaded in sequence. Based on the cooperation of the above sub-units, the DDS module can generate high-resolution, fast-response analog drive signals according to the frequency control word output by the phase-locked loop control logic module, providing stable resonant drive excitation for the MEMS. Its performance directly affects the tracking accuracy of the drive frequency and the resonant frequency, including:

[0068] Phase accumulator: based on the system clock F clk =50MHz is the trigger period. In each period, the frequency control word output by the phase-locked loop control logic module is accumulated once to finally generate a 32-bit (N=32) wide incremental sawtooth wave signal, which is the digital phase signal of the drive signal.

[0069] Sine lookup table: It uses a ROM chip with a storage depth of 8192, which pre-stores a complete cycle of sine wave data; it truncates the high bits of the 32-bit phase signal output by the phase accumulator, retaining only the high 13 bits (A=13) as the address input to the sine lookup table, and outputs the corresponding digital sine signal through address mapping;

[0070] DA conversion unit: The TLV320 DA conversion chip is selected. This chip has a conversion rate of 195kHz and a conversion accuracy of 14bit. It converts the digital sine signal output from the sine lookup table into an analog signal, thus completing the digital-to-analog conversion.

[0071] Low-pass filter unit: used to filter out the high-frequency noise components remaining in the analog signal after DA conversion, and output a smooth and noise-free MEMS drive signal.

[0072] The calculation formulas involved in the operation of the above sub-units are as follows:

[0073] (i) Formula for calculating output frequency: f o =(F clk / 2^N)*F w , where f o F is the DDS output drive frequency. clk =50MHz is the main clock frequency, N=32 is the phase signal bit width, F w For frequency control word;

[0074] (ii) Formula for calculating frequency resolution: Δf = F clk / 2^N=50M / 2^32=0.0116Hz;

[0075] It should be noted that the above parameter settings take into account the phase detection section. Increasing only the phase accumulator bit width N will worsen the phase truncation noise generated when the low-order bits of the phase signal are truncated. Increasing the sine lookup table depth simultaneously will multiply the FPGA logic resource usage, resulting in poor economic efficiency. Decreasing the system clock F... clk This will affect the accuracy of phase difference detection. Therefore, this embodiment adopts the above parameter combination to achieve a balance between performance and cost.

[0076] (III) MEMS Piezoresistive Feedback Signal Processing Module: This module employs an AD sampling + digital signal processing architecture to acquire the feedback signal output from the MEMS's built-in Wheatstone bridge piezoresistive detection circuit in real time. Through digital signal processing, it extracts the zero-crossing position of the MEMS deflection angle (i.e., deflection phase 0° or 180°), generating a precise phase feedback signal to provide data support for phase-locked loop control and illumination control. This includes:

[0077] AD sampling unit: The MCP33131 AD sampling chip is selected. The sampling rate of this chip is 1MHz and the resolution is 14bit. It collects the analog feedback signal output by the piezoresistive detection circuit in real time and converts it into a digital feedback signal.

[0078] Digital signal processing operations include:

[0079] (i) Low-pass filtering: Filters out high-frequency noise and random interference introduced by external hardware circuits, improving the signal-to-noise ratio;

[0080] (ii) Debiasing: Separate and filter out the DC bias component in the digital feedback signal and retain the AC signal that reflects the deflection state of the MEMS;

[0081] (iii) Linear interpolation processing: A linear interpolation algorithm is used to improve the 1us sampling resolution corresponding to a 1MHz sampling rate to a 0.02us resolution corresponding to a 50MHz equivalent sampling rate, thereby improving the phase detection accuracy of the feedback signal.

[0082] (iv) Zero-crossing detection: Set phase thresholds (digital signal amplitudes corresponding to 0° and 180°). When the processed signal crosses the threshold, it is determined to be a zero-crossing, and a pulse signal with the same frequency and duty cycle as the drive signal is generated—the rising edge of the pulse corresponds to a MEMS deflection phase of 0°, and the falling edge corresponds to a deflection phase of 180°. The corresponding phase detection accuracy is approximately Δθ = f o / F clk =1175*360° / 50M=0.00846° (where 1175Hz is the MEMS resonant frequency f) o (Estimated value); taking into account factors such as phase truncation noise, clock jitter, and hardware system noise, the actual detection error is controlled within ±0.05°, accounting for 1 / 1800 of the system's imaging area, meeting the imaging resolution requirement of 1024 or higher.

[0083] It should be noted that the above architecture cannot fully achieve the desired effect of this solution. This solution solves the problem of bidirectional stripe blurring after the phase-locked logic is working from another perspective, achieving bidirectional stripe alignment without increasing FPGA resources and hardware costs. The key lies in the following modules:

[0084] The laser beam control logic module is used to dynamically correct the laser beam emission delay based on the phase difference Δphase output by the phase-locked loop (PLL) control logic module. This compensates for phase deviations caused by the limited frequency resolution of the DDS, ensuring precise matching between the laser beam phase and the MEMS deflection angle phase, and achieving bidirectional stripe alignment. This includes:

[0085] Image signal storage: The FPGA integrates a RAM storage unit with a storage depth of 2048 (1024*2) to store the periodic image signal output by the image generation logic. Since the MEMS completes two imaging operations (0-π phase interval and π-2π phase interval) in one oscillation cycle, the RAM depth is designed according to the imaging resolution ×2 to ensure the complete image data storage of a single oscillation cycle.

[0086] Ideal lighting phase calculation: such as Figure 4 As shown, when the MEMS is in an ideal resonant state, the phase difference Δphase between the driving signal and the MEMS deflection angle is fixed at -90° (i.e., phase_res = phase_drive - 90°). At this time, the laser beam phase needs to coincide with the MEMS deflection angle phase. Therefore, the ideal beam phase formula is: phase_laser = phase_drive - 90°.

[0087] Actual illumination phase correction: Due to the limited frequency resolution of DDS (Δf=0.0116Hz), there is a slight deviation between the driving signal and the resonant frequency, causing Δphase to fluctuate within a certain range (e.g., ±0.4°). If the ideal formula is used, it will cause a deviation between the MEMS deflection phase phase_res and the illumination phase phase_laser (maximum 0.4°). Therefore, this solution corrects the illumination phase formula to: phase_laser=phase_drive-Δphase, and ensures stable matching between the illumination phase and the deflection angle phase by real-time compensation of Δphase deviation.

[0088] FPGA logic implementation: Since the detection of Δphase has a lag of one oscillation cycle (signal acquisition and processing of one cycle are required to calculate the Δphase of that cycle), it cannot be used in real time for the illumination correction of the current cycle. Considering that the change of MEMS resonant frequency is a slow process and the fluctuation of Δphase in adjacent cycles is very small, the logic of correcting the illumination delay of the current cycle using the Δphase of the previous cycle is adopted. That is, the illumination phase of the laser in the current cycle is calculated from the Δphase detected in the previous cycle, which solves the lag problem and ensures the correction accuracy.

[0089] Final result: Through the above delay correction, such as Figure 5 As shown in the circled area, the edges of the bright and dark stripes of the bidirectional lighting are precisely aligned, the imaging resolution meets the requirements of 1024 or higher for 3D cameras and scanners, the phase continuity is good, and there is no blurring.

[0090] Optionally, those skilled in the art can replace the implementation of the above modules without departing from the core principles of the present invention, specifically including:

[0091] (i) Replacement of piezoresistive detection signal processing: A hardware comparator can be used to replace the digital zero-crossing processing method. By setting the threshold voltage through the hardware comparator, the zero-crossing position of the piezoresistive feedback signal can be directly detected, the phase information can be extracted, and the digital processing flow can be simplified.

[0092] (ii) DDS implementation alternative: If the FPGA logic resource occupation and hardware cost are not considered, the phase accumulator bit width N and the sine lookup table depth can be increased simultaneously to improve the DDS frequency resolution, so that the phase deviation generated by the DDS frequency jump matches the phase detection error. Bidirectional alignment can be achieved without relying on laser output delay correction. However, this scheme will lead to a significant increase in hardware cost. Therefore, the scheme in this embodiment 1 is still the best option of this method.

[0093] Example 2: This example provides a bidirectional illumination alignment control system for a MEMS optomechanical system, such as... Figure 6 As shown, it includes:

[0094] The closed-loop phase-locked control module is used to perform closed-loop phase-locked control of the MEMS and track the MEMS resonant frequency of the MEMS drive frequency in real time.

[0095] The laser emission delay correction module is used to perform laser emission delay correction to compensate for the misalignment of bidirectional stripes caused by the deviation between the driving frequency and the resonant frequency.

[0096] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0097] Example 3: This example provides a computer-readable storage medium, including:

[0098] The storage medium is used to store computer software instructions for implementing the bidirectional illumination alignment control method of the MEMS optical engine described in Embodiment 1. It includes a program for executing the bidirectional illumination alignment control method of the MEMS optical engine. Specifically, the executable program can be built into the bidirectional illumination alignment control system of the MEMS optical engine described in Embodiment 2. In this way, the bidirectional illumination alignment control system of the MEMS optical engine can implement the bidirectional illumination alignment control method of the MEMS optical engine described in Embodiment 1 by executing the built-in executable program.

[0099] Furthermore, the computer-readable storage medium in this embodiment can be any combination of one or more readable storage media, wherein the readable storage medium includes an electrical, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof.

[0100] Unlike existing technologies, the bidirectional light alignment control method, system and medium of MEMS optomechanics proposed in this application can solve the problem of bidirectional alignment of structured light when driving MEMS at resonant frequency by coordinating MEMS closed-loop phase-locked control and laser light emission delay correction, combined with DDS module precise driving and piezoresistive signal high-precision processing. This ensures high frame rate while avoiding optical power waste and significantly improves light energy utilization and 3D imaging quality.

[0101] It should be understood that in the various embodiments of this document, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0102] It should also be understood that, in the embodiments herein, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0103] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0104] In the embodiments provided herein, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0105] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described herein, depending on actual needs.

[0106] Furthermore, the functional units in the various embodiments of this document can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0107] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this paper, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this paper. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0108] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A bidirectional illumination alignment control method for MEMS optomechanics, characterized in that, Includes the following steps: In response to MEMS closed-loop phase-locked control operation: Control the MEMS driving frequency to track the MEMS resonant frequency in real time; In response to laser emission delay correction operation: Compensation for bidirectional stripe misalignment caused by the deviation between the driving frequency and the resonant frequency.

2. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 1, characterized in that: The MEMS closed-loop phase-locked control operation further includes: Acquire the piezoresistive feedback signal of the MEMS and detect the phase difference between the piezoresistive feedback signal and the MEMS driving signal; Based on the correspondence between the phase difference and the resonant frequency of the MEMS and the frequency of the drive signal, the frequency control word of the drive signal generation unit is adjusted, and the frequency of the drive signal is controlled to track the change of the resonant frequency by adjusting the frequency control word.

3. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 2, characterized in that: The MEMS drive signal is generated based on the DDS module; The DDS module generates a phase signal based on the system clock accumulated frequency control word, and outputs a digital sine signal through the high-order address mapping of the phase signal. After DA conversion and low-pass filtering, the MEMS drive signal is obtained.

4. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 2, characterized in that: The acquisition of the piezoresistive feedback signal from the MEMS further includes: The analog feedback signal output by the MEMS piezoresistive detection circuit is acquired by the AD sampling unit and converted into a digital feedback signal. The digital feedback signal is sequentially processed by low-pass filtering, bias removal, linear interpolation, and zero-crossing point determination to extract the zero-crossing point position of the MEMS deflection angle and generate a phase feedback pulse signal with the same frequency as the MEMS drive signal and a duty cycle of 50%.

5. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 1, characterized in that: The laser emission delay correction operation further includes: In the current MEMS oscillation cycle, the laser emission delay of the current MEMS oscillation cycle is corrected by using the actual phase difference of the previous oscillation cycle, thereby controlling the phase of the laser emission to match the phase of the MEMS deflection angle.

6. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 5, characterized in that: The actual phase difference is the phase difference between the driving signal phase and the MEMS deflection angle phase calculated during the MEMS closed-loop phase-locked control process in the current MEMS oscillation period.

7. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 2, characterized in that: The step of adjusting the frequency control word of the drive signal generation unit based on the correspondence between the phase difference and the resonant frequency of the MEMS and the drive signal frequency further includes: When the frequency of the driving signal is less than the resonant frequency, the phase difference is between -90° and 0, and the frequency control word is increased; When the frequency of the driving signal is less than the resonant frequency, the phase difference is equal to -90°, and the current frequency control word is maintained; When the frequency of the driving signal is greater than the resonant frequency, the phase difference is between -180° and -90°, and the frequency control word is reduced.

8. The bidirectional illumination alignment control method for MEMS optomechanics according to claim 3, characterized in that: The output frequency of the DDS module satisfies a first formula, which is: f o =(F clk / 2^N)*F w ; The frequency resolution of the DDS module satisfies the second formula, which is: △f=F clk / 2^N; In the first formula and the second formula, f o F is the drive signal frequency, Δf is the frequency resolution of the DDS module, and F clk The master clock frequency, N is the phase signal bit width, F w This is the frequency control word.

9. A bidirectional illumination alignment control system for a MEMS optomechanism based on the bidirectional illumination alignment control method for a MEMS optomechanism according to any one of claims 1 to 8, characterized in that, The system includes: The closed-loop phase-locked control module is used to perform closed-loop phase-locked control of the MEMS and track the MEMS resonant frequency of the MEMS drive frequency in real time. The laser emission delay correction module is used to perform laser emission delay correction to compensate for the misalignment of bidirectional stripes caused by the deviation between the driving frequency and the resonant frequency.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the bidirectional illumination alignment control method of the MEMS optomechanism according to any one of claims 1 to 8.

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