ITOF phase method laser displacement sensor

Abstract

The invention discloses an ITOF phase method laser displacement sensor, which is provided with a power supply module, a control module, a measuring tape signal generation module, a laser driving module and an APD receiving module, and is characterized in that a main control unit receives multiple groups of measuring tape frequency pairs generated by the measuring tape signal generation module; the first laser unit and the second laser unit are controlled to measure each group of measuring tape frequency pairs to obtain corresponding distance measuring signals and reference signals, and the main control unit controls the sampling rate of the sampling unit according to the difference frequency between the distance measuring signals and the reference signals; the sampling unit samples sinusoidal voltage signals output by the APD receiving module according to the sampling rate to obtain a plurality of sampling sequences, and the main control unit performs phase ranging calculation on each sampling sequence according to the difference frequency to obtain the target distance of each group of measuring tape frequency pairs, so that the anti-interference capability and the environmental adaptability of the sensor in a complex environment are improved. And the measurement precision and reliability are improved, so that the requirements of medium-short distance high-precision laser displacement measurement are met.

Description

Technical Field

[0001] This invention belongs to the field of laser ranging technology, and particularly relates to an ITOF phase-based laser displacement sensor. Background Technology

[0002] Laser ranging technology has wide applications in many fields. A laser ranging sensor is a distance sensor module based on laser ranging technology. Laser ranging technology has advantages such as good directivity, high accuracy, large range, fast measurement speed, and non-contact measurement. Its disadvantage is that it is susceptible to interference from strong light. Based on different principles, laser ranging technology can currently be mainly divided into several categories, including triangulation ranging, interferometric ranging, pulse ranging, and continuous wave ranging (including phase-based and frequency-modulated continuous wave methods). Each category is applied to different scenarios based on its different characteristics. Among them, phase-based laser ranging is more mature in the field of short to medium distance laser ranging.

[0003] Currently, mainstream sensor manufacturers produce phase-based laser rangefinders with measurement ranges of 1m, 2m, 5m, 10m, 20m, and 50m. However, the ITOF phase-based method struggles to balance accuracy and measurement distance; it offers relatively high accuracy at close ranges, but accuracy decreases as the measurement distance increases. Existing phase-based laser rangefinders on the market primarily employ single-path and dual-path optical path designs, and there is still room for improvement in parameters such as measurement range and accuracy.

[0004] While existing ITOF methods can achieve high accuracy (e.g., ±2mm) at close ranges (e.g., within 10m), accuracy decreases significantly with increasing measurement distance. For example, accuracy decreases by 1mm for every 10m increase, limiting their application in medium- to long-distance measurements. Single-path sensors are susceptible to interference in complex environments, affecting measurement accuracy and reliability. While dual-path structures improve anti-interference capabilities to some extent, existing designs still have shortcomings in signal processing and accuracy enhancement. Therefore, there is an urgent need to provide an ITOF phase-based laser displacement sensor to address the aforementioned technical problems. Summary of the Invention

[0005] In view of this, the present invention provides an ITOF phase-based laser displacement sensor, which can solve the shortcomings of existing phase-based TOF laser ranging sensors in balancing accuracy and measurement distance, improve the sensor's anti-interference ability and environmental adaptability in complex environments, and optimize the hardware and software design, adopt better algorithms, improve measurement accuracy and reliability, so as to meet the needs of high-precision laser displacement measurement over medium and short distances. The specific technical solution is as follows.

[0006] This invention provides an ITOF phase-shift laser displacement sensor, which includes a power supply module, a control module, a scale signal generation module, a laser drive module, and an APD receiving module. The power supply module and the APD receiving module are both connected to the control module, and the scale signal generation module and the APD receiving module are both connected to the laser drive module. The laser driving module includes a first laser unit and a second laser unit, and the control module includes a main control unit and a sampling unit. The main control unit and the sampling unit are both connected to the APD receiving module, and the laser driving module is connected to the main control unit. The main control unit is used to receive multiple sets of measuring scale frequency pairs generated by the measuring scale signal generation module, and control the first laser unit and the second laser unit to measure each set of measuring scale frequency pairs to obtain the corresponding ranging signal and reference signal. The main control unit controls the sampling rate of the sampling unit according to the frequency difference between the ranging signal and the reference signal. The sampling unit is used to sample the sinusoidal voltage signal output by the APD receiving module according to the sampling rate to obtain multiple sampling sequences. The main control unit performs phase ranging calculation on each of the sampling sequences according to the difference frequency to obtain the target distance of each set of measuring frequency pairs.

[0007] As a preferred embodiment of the above technical solution, each set of measuring frequency pairs includes a first frequency and a second frequency, and the main control unit uses the Gertz algorithm to calculate the difference frequency between the second frequency and the first frequency. Complex spectral values ​​at corresponding frequency points And based on the complex spectrum value Calculate the phase of the external optical path signal corresponding to the first laser unit and the phase of the internal optical path signal corresponding to the second laser unit, as well as the phase difference under the current measuring scale. The corresponding expressions are: (1) The main control unit calculates the fuzzy distance under the current measuring scale according to the phase ranging algorithm, and the corresponding expression is: (2) in, The phase of the external optical path signal. Let c be the phase of the signal in the internal optical path, and c be the speed of light. The current modulation frequency; A set of fuzzy distances is obtained by sequentially calculating the modulation frequencies of multiple sets of measuring scale frequency pairs using formulas (1) and (2); The target distance for each pair of measuring frequency pairs is obtained by combining multiple fuzzy distances using a step-by-step defuzzification algorithm, wherein the first frequency is the frequency of the local oscillator signal, and the second frequency is the frequency of the main oscillator signal or the modulation frequency.

[0008] As a preferred embodiment of the above technical solution, the measuring signal generation module includes chip U7, resistors R54, R55, R56, R57, R58, R59, R60, R61, capacitors C47, C48, C49, C50, C51, C52, inductors L9, L10, L11, L12, and MOSFET Q10; Capacitors C48 and C49 are connected in parallel to chip U7 and one end of inductor L11. One end of capacitor C50, one end of resistors R57, R58, R59, and R60 are all connected to chip U7. Resistors R56 and R61 are connected to the other end of capacitor C50. The other end of resistor R59 is connected to the other end of resistor R60. One end of resistor R54, one end of capacitor C47, and the gate of MOSFET are all connected to resistor R55. The other end of resistor R54 is connected to inductor L10, the other end of capacitor C47, and the source of MOSFET Q10. The other ends of inductors L9 and L11 are both connected to the drain of MOSFET Q10. The other end of resistor R57 is connected to the laser driver module. The other end of resistor R58 is connected to the APD receiver module. Capacitors C51 and C52 are connected to chip U7 and inductor L12.

[0009] As a preferred embodiment of the above technical solution, the laser driving module further includes an analog switch U8, capacitors C53, C54, C55, C56, C57, C58, C59, C60, C61, C62, C63, C64, C65, C66, C67, C68, C69, C70, C71, C72, C107, C108, C109, C110, inductors L13, L14, L15, transistors Q11 and Q12, and a comparator U9. Inductor L13 is connected to capacitors C53, C60, one end of inductor L14, capacitors C54, C61, chip U8, capacitors C110, C55, C56, the first laser unit, the second laser unit, capacitors C57, C58, C59, and C108. Capacitors C100, C55, and C56 are connected in parallel, as are capacitors C57, C58, C59, and C108. Inductor L1... 4. The other end of capacitor C62 is connected to one end of capacitor C6 and the collector of transistor Q11. The other end of capacitor C62 is connected to analog switch U8 and one end of inductor L15. The base of transistor Q11 is connected to one end of resistor R64, one end of capacitor C70, and one end of capacitor C66. The other end of capacitor C66 is connected to one end of capacitor C68 and one end of capacitor C65. The other end of capacitor C65 is connected to capacitor C67. The other end of capacitor C67 is connected to the other end of capacitor C68. Capacitor C7... The other end of the transistor Q11 is grounded, the other end of the inductor L15 is connected to the collector of the transistor Q12, the emitter of the transistor Q12 is connected to the resistor R71, the base of the transistor Q12 is connected to one end of the resistor R67, the other end of the resistor R67 is connected to one end of the capacitor C64 and the output of the comparator U9, the positive input of the comparator U9 is connected to one end of the capacitor C71 and one end of the resistor R68, the capacitor C69 and the capacitor C109 are connected in parallel to the comparator U9, the negative input of the comparator U9 is connected to the other end of the capacitor C64, the resistor R65 and the resistor R66, the other end of the resistor R68 is connected to one end of the resistor R70, one end of the capacitor C72 and the resistor R69, and the other end of the capacitor C71, the other end of the resistor R70 and the other end of the capacitor C72 are grounded. The first laser unit includes an external optical path laser tube connected to the analog switch U8, and the second laser unit includes an internal optical path laser tube connected to the analog switch U8.

[0010] As a preferred embodiment of the above technical solution, the APD receiving module includes resistors R83, R84, R85, R86, R87, R88, R89, R90, R91, R92, R93, R94, and R95; capacitors C88, C89, C90, C91, C92, C93, C94, C95, C96, C97, C98, C99, C100, C101, C102, and C103; comparator U10; operational amplifier U11A; and operational amplifier U11B. Resistor R83 is connected to one end of capacitors C89, C91, and C93, one end of resistor R87, and the positive input terminal of comparator U10. The other end of capacitor C89 is connected to the other ends of capacitors C91 and C93, and the other end of resistor R87. One end of resistor R90 is connected to one end of capacitors C99 and C95, one end of capacitor C103, and the negative input terminal of comparator U10. The other end of resistor R90 is connected to one end of capacitor C98. The other end of C98 is connected to the other end of capacitor C99 and grounded. The other end of resistor R95 is connected to the other end of capacitor C103, one end of resistor R88, and the output of comparator U10. Resistor R84 is connected to one end of capacitor C92, one end of capacitor C94, and comparator U10. The other end of capacitor C92 is connected to the other end of capacitor C94 and grounded. The other end of resistor R88 is connected to one end of resistor R89 ​​and one end of capacitor C97. The other end of resistor R89 ​​is connected to one end of capacitor C95. One end of capacitor C88 is connected; the other end of capacitor C95 is connected to one end of resistor R85 and the negative input terminal of op-amp U11A; the other end of resistor R88 is connected to the other end of resistor R85, the output terminal of op-amp U11A, and one end of resistor R91; one end of capacitor C100 is connected to one end of resistor R92; the other end of resistor R92 is connected to one end of resistor R94, one end of capacitor C101, the positive input terminal of op-amp U11A, and the positive input terminal of op-amp U11B; the other end of resistor R94... One end of the capacitor is connected to the other end of capacitor C101 and grounded. The other end of capacitor C100 is grounded. The other end of resistor R91 is connected to one end of capacitor C96 and one end of capacitor C90. The other end of capacitor C96 is connected to the negative input terminal of op-amp U11B and one end of resistor R86. The other end of capacitor C90 is connected to the other end of resistor R86, the output terminal of op-amp U11B, and one end of resistor R93. The other end of resistor R93 is connected to one end of capacitor C102. The other end of capacitor C102 is grounded.

[0011] As a preferred embodiment of the above technical solution, the power module includes a DC-DC conversion circuit, which includes chip U5, resistors R47, R48, R49, and R50, capacitors C37, C38, C39, C40, C41, and C42, inductors L7 and L8, diodes D9, D10, and D11, and transistor Q9. One end of resistor R48 is connected to one end of capacitor C37 and inductor L7. The other end of capacitor C37 is connected to capacitor C38 and the anode of diode D10. The other end of inductor L7 is connected to the other end of capacitor C38, the cathode of diode D10, one end of resistor R47, and the anode of diode D9. The other end of resistor R47 is connected to the cathode of diode D11. The cathode of diode D9 is connected to the collector of transistor Q9. The emitter of transistor Q9 is connected to one end of capacitor C39 and one end of capacitor C40. The other end of capacitor C39 and capacitor C40 are connected in parallel to ground. The other end of capacitor C40 is connected to one end of resistor R50, one end of capacitor C36, resistor R49, and one end of capacitor C41. The other end of capacitor C36 is connected to one end of inductor L8 and chip U5. The other end of inductor L8 is connected to the other end of resistor R49, one end of capacitor C41, and one end of capacitor C42. The other end of capacitor C41 is connected to the other end of resistor R49, chip U5, and resistor R50. The other end of capacitor C42 and the other end of resistor R50 are grounded.

[0012] As a preferred embodiment of the above technical solution, the power module further includes an LDO circuit connected to the DC-DC conversion circuit. The LDO circuit includes a chip U6, resistors R51, R52, and R53, and capacitors C43, C44, C45, and C46. One end of resistor R51 is connected to capacitor C46 and chip U6, and the other end of resistor R51 is connected to one end of capacitor C45. The other end of capacitor C45 is connected to the other end of capacitor C46, ​​chip U6, one end of resistor R53, and one end of capacitor C43. Resistor R53 is connected to one end of capacitor C44 and one end of resistor R52. The other end of capacitor C44 is connected to the other end of resistor R52 and one end of capacitor C43, and is connected to chip U6. Capacitor C43 is also connected.

[0013] As a preferred embodiment of the above technical solution, the power module further includes a Boost converter circuit connected to the main control unit. The Boost converter circuit includes resistors R72, R73, R74, R75, R76, R77, R78, and R79; capacitors C73, C74, C75, C76, C77, and C78; inductors L17 and L18; MOSFET Q13; and switching diode D14. Inductor L18 is connected to one end of resistor R72. The other end of resistor R72 is connected to one end of capacitor C73, one end of capacitor C74, and one end of inductor L17. The other end of capacitor C73 is connected to the other end of capacitor C74 and grounded. The other end of inductor L17 is connected to the drain of MOSFET Q13 and the power input terminal of switching diode D14. Switching diode D14 is connected to one end of capacitor C75 and one end of resistor R73. The other end of resistor R73 is connected to one end of capacitor C76 and... One end of resistor R74, one end of capacitor C77, and one end of resistor R75 are connected. The other end of resistor R75 is connected to one end of resistors R79 and R77. The other ends of capacitors C75, C76, R79, and C77 are connected to the source of MOSFET Q13 and grounded. The gate of MOSFET Q13 is connected to one end of resistors R76, C78, ​​and R78. The other end of capacitor C78 is connected to the other end of resistor R78 and grounded.

[0014] As a preferred embodiment of the above technical solution, the Boost circuit further includes capacitors C81, C82, C83, C84, C85, C86, and C87, resistors R80, R81, and R82, inductors L19, L20, and L21, and transistor Q14. One end of capacitor C79 is connected to capacitor C80 and grounded. The other end of capacitor C79 is connected to the other end of capacitor C80 and one end of inductor L19. Inductor L19 is connected to one end of inductor L20, capacitor C82, and transistor Q14. The base of transistor Q14 is connected to one end of resistor R80 and one end of capacitor C84. The other end of resistor R80 is connected to one end of capacitor C83 and one end of resistor R81. The other end of capacitor C84 is connected to one end of inductor L21 and capacitor C82. 5. Connect one end of capacitor C85 to one end of resistor R82 and one end of capacitor C86. Connect the other end of capacitor C86 to one end of capacitor C87 and the APD receiver module. Connect the other end of inductor L20 to one end of capacitor C81. Connect the other end of capacitor C81 to resistor R74. Connect the other end of capacitor C82, the emitter of transistor Q14, the other end of capacitor C83, the other end of inductor L21, the other end of resistor R82, and the other end of capacitor C87 to ground.

[0015] As a preferred embodiment of the above technical solution, the laser displacement sensor further includes a peripheral device module connected to the main control unit. The peripheral device module includes at least one of a programming and communication interface, an external button, or a display screen. The main control unit includes an MCU with the model number GD32F425.

[0016] This invention provides an ITOF phase-based laser displacement sensor. It comprises a power supply module, a control module, a scale signal generation module, a laser drive module, and an APD receiving module. The laser drive module includes a first laser unit and a second laser unit. The control module includes a main control unit and a sampling unit. The main control unit receives multiple sets of scale frequency pairs generated by the scale signal generation module and controls the first and second laser units to measure each set of scale frequency pairs to obtain corresponding distance signals and reference signals. The main control unit controls the sampling rate of the sampling unit based on the frequency difference between the distance signals and the reference signals. The sampling unit samples the sinusoidal voltage signal output by the APD receiving module according to the sampling rate to obtain multiple sampling sequences. The main control unit performs phase ranging calculations on each sampling sequence based on the frequency difference to obtain the target distance for each set of scale frequency pairs. This improves the sensor's anti-interference capability and environmental adaptability in complex environments. Simultaneously, it optimizes the hardware and software design, employs superior algorithms, and enhances measurement accuracy and reliability to meet the needs of high-precision laser displacement measurement over short to medium distances. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural block diagram of the ITOF phase-based laser displacement sensor provided by the present invention; Figure 2 This invention provides a schematic diagram of the working principle of an ITOF phase-based laser displacement sensor. Figure 3 A flowchart illustrating the operation of the ITOF phase-based laser displacement sensor provided by this invention; Figure 4 A circuit diagram of the control module provided for this invention; Figure 5 A circuit diagram of the LDO circuit provided for this invention; Figure 6 A circuit diagram of the Boost converter circuit provided by this invention; Figure 7 The circuit diagram of the measuring scale signal generation module provided by the present invention; Figure 8 A circuit diagram of the laser driving module provided by the present invention; Figure 9 The circuit diagram of the APD receiving module provided by the present invention.

[0019] The specifications for the symbols of the main components are as follows; 100-Power supply module; 110-Control module; 111-Main control unit; 112-Sampling unit; 120-Measurement signal generation module; 130-Laser drive module; 131-First laser unit; 132-Second laser unit; 140-APD receiving module. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] See Figure 1 , Figure 2 and Figure 3 The present invention provides an ITOF phase-shift laser displacement sensor, which includes a power supply module 100, a control module 110, a scale signal generation module 120, a laser drive module 130, and an APD receiving module 140. The power supply module 100 and the APD receiving module 140 are both connected to the control module 110, and the scale signal generation module 120 and the APD receiving module 140 are both connected to the laser drive module 130. The laser driving module 130 includes a first laser unit 131 and a second laser unit 132. The control module 110 includes a main control unit 111 and a sampling unit 112. The main control unit 111 and the sampling unit 112 are both connected to the APD receiving module 140. The laser driving module 130 is connected to the main control unit 111. The main control unit 111 is used to receive multiple sets of measuring frequency pairs generated by the measuring scale signal generation module 120, and control the first laser unit 131 and the second laser unit 132 to measure each set of measuring frequency pairs to obtain the corresponding ranging signal and reference signal. The main control unit 111 controls the sampling rate of the sampling unit 112 according to the frequency difference between the ranging signal and the reference signal. The sampling unit 112 is used to sample the sinusoidal voltage signal output by the APD receiving module 140 according to the sampling rate to obtain multiple sampling sequences. The main control unit 111 performs phase ranging calculation on each of the sampling sequences according to the difference frequency to obtain the target distance of each set of measuring frequency pairs.

[0022] In this embodiment, each pair of measuring scale frequencies includes a first frequency and a second frequency, and the main control unit uses the Geertz algorithm to calculate the difference frequency between the second frequency and the first frequency. Complex spectral values ​​at corresponding frequency points And based on the complex spectrum value The phase of the external optical path signal corresponding to the first laser unit 131 and the phase of the internal optical path signal corresponding to the second laser unit 132 are calculated respectively, as well as the phase difference under the current measuring scale. The corresponding expressions are: (1) The main control unit 111 calculates the fuzzy distance under the current measuring scale according to the phase ranging algorithm, and the corresponding expression is: (2) in, The phase of the external optical path signal. Let c be the phase of the signal in the internal optical path, and c be the speed of light. The current modulation frequency; A set of fuzzy distances is obtained by sequentially calculating the modulation frequencies of multiple sets of measuring scale frequency pairs using formulas (1) and (2); The target distance for each pair of measuring frequency pairs is obtained by combining multiple fuzzy distances using a step-by-step defuzzification algorithm, wherein the first frequency is the frequency of the local oscillator signal, and the second frequency is the frequency of the main oscillator signal or the modulation frequency.

[0023] It should be noted that the laser displacement sensor also includes a peripheral device module connected to the main control unit 111. The peripheral device module includes at least one of a programming and communication interface, external buttons, or a display screen. The main control unit includes an MCU of model GD32F425. The main components of the phase-based ITOF laser displacement sensor of this invention are software and hardware design. The software design, with the MCU chip (main control unit) as the core, completes functions such as program programming, communication protocol, peripheral control, signal acquisition, data processing, and interactive output. The core of the system lies in overcoming phase ambiguity and achieving high precision through a multi-scale phase measurement method. The MCU controls a high-frequency clock chip (scale signal generation module) to generate multiple modulation signals of different frequencies (i.e., "electric scales"). The laser drive module uses these signals to modulate the laser and emit it. The lasers returned from the inner and outer optical paths are received by the APD, and the high-frequency optical signal is down-converted to a low-frequency electrical signal using heterodyne detection technology. The MCU synchronously acquires the signals from the inner and outer optical paths, and accurately extracts the phase difference between the two signals through an optimized Gertz algorithm, thereby calculating the flight time and target distance. The dual-optical-path design provides a real-time reference, effectively compensating for measurement errors caused by circuit delays and environmental temperature drift.

[0024] Phase-based laser ranging technology calculates the distance by modulating a laser with a sinusoidal wave and measuring the phase difference between the emitted and reflected laser signals. Relying on the accuracy of phase difference detection, phase-based measurements can achieve millimeter-level precision as well as a large range of hundreds of meters, balancing both accuracy and range.

[0025] The execution process of the ITOF phase-based laser displacement sensor provided by this invention includes: (1) System initialization and parameter configuration: Initializing the MCU and various peripherals (ADC, DAC, I2C, timer, etc.), configuring the MS5351 clock chip through the I2C bus, and generating multiple preset scale frequency pairs (main oscillator and local oscillator). For example, three frequency pairs can be configured: , , ,in, f1~f3 For different modulation frequencies, (1) Fixed difference frequency (e.g., 10kHz); (2) Measurement control and signal acquisition: The MCU controls the analog switch to sequentially switch the external optical path laser (range signal) and the internal optical path laser (reference signal). For each optical path and each measuring scale frequency, the ADC (sampling unit) is activated at a frequency much higher than the difference frequency. The sampling rate is used to synchronously or continuously sample the sinusoidal voltage signal output by the APD module to obtain a discrete signal sequence with a fixed number of points (e.g., N=512); (3) Core signal processing and phase calculation: The phase extraction is refined by the Goetzeel algorithm: For each sampling sequence, the Goetzeel algorithm is applied to calculate the phase extraction at the difference frequency. For the complex spectral value X(k) at the corresponding frequency point, calculate the phase φ_outer of the external optical path signal and the phase φ_inner of the internal optical path signal, and then calculate the phase difference under the current measuring scale: Δφ= φ_outer -φ_inner; Based on the phase-based ranging principle, calculate the fuzzy distance under the current measuring scale: Where c is the speed of light. The modulation frequency currently in use. Multi-scale data fusion and defuzzification: The above process is repeated sequentially using different modulation frequencies f1, f2, f3,... to obtain a set of fuzzy distances L1', L2', L3',... Using the remainder theorem or a stepwise defuzzification algorithm, the multiple fuzzy distances are combined and calculated to obtain a unique and precise absolute distance L (target distance).

[0026] It should be understood that the hardware consists of a control module 110, a power supply module 100, a measuring scale signal generation module 120, a laser drive module 130, and an APD receiving module 140. The control module 110 is based on an MC and uses a GD32F425 MCU. It mainly controls, communicates, and processes data for various peripheral devices of the system. Peripheral devices include programming and communication interfaces, external buttons, and displays. It performs functions such as program burning, serial communication debugging, input / output, and distance measurement result display. By configuring a power supply module 100, a control module 110, a scale signal generation module 120, a laser drive module 130, and an APD receiving module 140, the laser drive module 130 includes a first laser unit 131 and a second laser unit 132. The control module 110 includes a main control unit 111 and a sampling unit 112. The main control unit 111 receives multiple sets of scale frequency pairs generated by the scale signal generation module 120 and controls the first laser unit 111 and the second laser unit 112 to measure each set of scale frequency pairs to obtain the corresponding ranging signal and reference signal. The main control unit controls the sampling rate of the sampling unit according to the difference frequency between the ranging signal and the reference signal. The sampling unit samples the sinusoidal voltage signal output by the APD receiving module according to the sampling rate to obtain multiple sampling sequences. The main control unit 111 performs phase ranging calculation on each sampling sequence according to the difference frequency to obtain the target distance of each set of scale frequency pairs. This improves the sensor's anti-interference capability and environmental adaptability in complex environments. At the same time, it optimizes the hardware and software design, adopts better algorithms, and improves the measurement accuracy and reliability to meet the needs of high-precision laser displacement measurement over medium and short distances.

[0027] Specifically, the measuring signal generation module includes chip U7, resistors R54, R55, R56, R57, R58, R59, R60, R61, capacitors C47, C48, C49, C50, C51, C52, inductors L9, L10, L11, L12, and MOSFET Q10; Capacitors C48 and C49 are connected in parallel to chip U7 and one end of inductor L11. One end of capacitor C50, one end of resistors R57, R58, R59, and R60 are all connected to chip U7. Resistors R56 and R61 are connected to the other end of capacitor C50. The other end of resistor R59 is connected to the other end of resistor R60. One end of resistor R54, one end of capacitor C47, and the gate of MOSFET are all connected to resistor R55. The other end of resistor R54 is connected to inductor L10, the other end of capacitor C47, and the source of MOSFET Q10. The other ends of inductors L9 and L11 are both connected to the drain of MOSFET Q10. The other end of resistor R57 is connected to the laser driver module. The other end of resistor R58 is connected to the APD receiver module. Capacitors C51 and C52 are connected to chip U7 and inductor L12.

[0028] In this embodiment, as Figure 7 As shown, the scale measurement signal generation module uses the MS5351 high-frequency clock chip as its core. The MS5351 chip is a CMOS clock generator controlled via the IIC bus. Based on phase-locked loop (PLL) frequency synthesis technology, it can be flexibly configured to output signals from 2.5kHz to 200MHz through multiple channels, meeting the requirements of multi-scale measurement technology and differential frequency phase measurement technology. This chip generates high-frequency master oscillator and local oscillator signals, such as 172.5MHz and 172.51MHz, providing stable high-frequency signals for subsequent mixing circuits and laser modulation drive circuits. Resistors R55 (FLL_PWR_SW), R56 (CLK_Signal), R59 (FLL_SCL), and R60 (FLL_SDA) are all connected to the main control unit, while resistor R58 (APD_Signal) is connected to capacitors C86 and C87 in the BOOST boost circuit.

[0029] Optionally, the laser driving module further includes an analog switch U8, capacitors C53, C54, C55, C56, C57, C58, C59, C60, C61, C62, C63, C64, C65, C66, C67, C68, C69, C70, C71, C72, C107, C108, C109, C110, inductors L13, L14, L15, transistors Q11 and Q12, and a comparator U9. Inductor L13 is connected to capacitors C53, C60, one end of inductor L14, capacitors C54, C61, chip U8, capacitors C110, C55, C56, the first laser unit, the second laser unit, capacitors C57, C58, C59, and C108. Capacitors C100, C55, and C56 are connected in parallel, as are capacitors C57, C58, C59, and C108. Inductor L1... 4. The other end of capacitor C62 is connected to one end of capacitor C6 and the collector of transistor Q11. The other end of capacitor C62 is connected to analog switch U8 and one end of inductor L15. The base of transistor Q11 is connected to one end of resistor R64, one end of capacitor C70, and one end of capacitor C66. The other end of capacitor C66 is connected to one end of capacitor C68 and one end of capacitor C65. The other end of capacitor C65 is connected to capacitor C67. The other end of capacitor C67 is connected to the other end of capacitor C68. Capacitor C7... The other end of the transistor Q11 is grounded, the other end of the inductor L15 is connected to the collector of the transistor Q12, the emitter of the transistor Q12 is connected to the resistor R71, the base of the transistor Q12 is connected to one end of the resistor R67, the other end of the resistor R67 is connected to one end of the capacitor C64 and the output of the comparator U9, the positive input of the comparator U9 is connected to one end of the capacitor C71 and one end of the resistor R68, the capacitor C69 and the capacitor C109 are connected in parallel to the comparator U9, the negative input of the comparator U9 is connected to the other end of the capacitor C64, the resistor R65 and the resistor R66, the other end of the resistor R68 is connected to one end of the resistor R70, one end of the capacitor C72 and the resistor R69, and the other end of the capacitor C71, the other end of the resistor R70 and the other end of the capacitor C72 are grounded. The first laser unit includes an external optical path laser tube connected to the analog switch U8, and the second laser unit includes an internal optical path laser tube connected to the analog switch U8.

[0030] In this embodiment, as Figure 8 As shown, the laser drive module mainly performs constant power drive of the laser diode and amplification of the main oscillation signal. It amplifies the main oscillation signal generated by the MS5351 clock chip and controls the switching between the internal and external lasers through the direct modulation technology of the laser diode and the analog switch SGM3157, so that the laser carries the frequency and phase information of the modulation signal and is emitted. Capacitors C65 and C67 in the laser drive module are connected to resistor R57 (Laser_Signal) in the ruler signal generation module, resistor R69 (Laser_PWM) is connected to the main control unit, and the emitter of transistor Q12 and resistor R71 (Laser_ADC) are connected to the main control unit.

[0031] Optionally, the APD receiving module includes resistors R83, R84, R85, R86, R87, R88, R89, R90, R91, R92, R93, R94, and R95; capacitors C88, C89, C90, C91, C92, C93, C94, C95, C96, C97, C98, C99, C100, C101, C102, and C103; comparator U10; operational amplifier U11A; and operational amplifier U11B. Resistor R83 is connected to one end of capacitors C89, C91, and C93, one end of resistor R87, and the positive input terminal of comparator U10. The other end of capacitor C89 is connected to the other ends of capacitors C91 and C93, and the other end of resistor R87. One end of resistor R90 is connected to one end of capacitors C99 and C95, one end of capacitor C103, and the negative input terminal of comparator U10. The other end of resistor R90 is connected to one end of capacitor C98. The other end of C98 is connected to the other end of capacitor C99 and grounded. The other end of resistor R95 is connected to the other end of capacitor C103, one end of resistor R88, and the output of comparator U10. Resistor R84 is connected to one end of capacitor C92, one end of capacitor C94, and comparator U10. The other end of capacitor C92 is connected to the other end of capacitor C94 and grounded. The other end of resistor R88 is connected to one end of resistor R89 ​​and one end of capacitor C97. The other end of resistor R89 ​​is connected to one end of capacitor C95. One end of capacitor C88 is connected; the other end of capacitor C95 is connected to one end of resistor R85 and the negative input terminal of op-amp U11A; the other end of resistor R88 is connected to the other end of resistor R85, the output terminal of op-amp U11A, and one end of resistor R91; one end of capacitor C100 is connected to one end of resistor R92; the other end of resistor R92 is connected to one end of resistor R94, one end of capacitor C101, the positive input terminal of op-amp U11A, and the positive input terminal of op-amp U11B; the other end of resistor R94... One end of the capacitor is connected to the other end of capacitor C101 and grounded. The other end of capacitor C100 is grounded. The other end of resistor R91 is connected to one end of capacitor C96 and one end of capacitor C90. The other end of capacitor C96 is connected to the negative input terminal of op-amp U11B and one end of resistor R86. The other end of capacitor C90 is connected to the other end of resistor R86, the output terminal of op-amp U11B, and one end of resistor R93. The other end of resistor R93 is connected to one end of capacitor C102. The other end of capacitor C102 is grounded.

[0032] In this embodiment, as Figure 9As shown, the APD receiver module also includes terminal P5, resistor R96, capacitor C104, capacitor C105, and capacitor C106. Pin 4 (HV) of terminal P5 is connected to the cathode of the avalanche photodiode. Pin 1 (ADC_SAMPLING) of terminal P5 is connected to resistor R93 and capacitor C102. One end of capacitor C104 is connected to one end of resistor R96. The other end of resistor R96 is connected to one end of capacitor C105 (VDD_AMP), one end of capacitor C106, and operational amplifier U11A. The other ends of capacitor C104, capacitor C105, and capacitor C106 are grounded.

[0033] The APD receiver module mainly consists of an avalanche photodiode (APD). The power supply module's BOOST boost circuit provides the APD (receiver module) with DC bias voltage and local oscillator signal amplification. Under a suitable DC bias voltage, the APD receives the ranging laser light reflected from the surface under test and converts it into a photocurrent carrying frequency and phase information. The APD's electrical heterodyne mixing technology achieves the difference frequency between the external optical path master oscillator signal and the internal optical path local oscillator signal. Finally, the photocurrent is amplified by a TIA transimpedance amplifier circuit and converted into a voltage signal. After passing through two stages of bandpass filtering, the signal is provided to the ADC for signal sampling.

[0034] Optionally, the power module includes a DC-DC conversion circuit, which includes chip U5, resistors R47, R48, R49, and R50, capacitors C37, C38, C39, C40, C41, and C42, inductors L7 and L8, diodes D9, D10, and D11, and transistor Q9. One end of resistor R48 is connected to one end of capacitor C37 and inductor L7. The other end of capacitor C37 is connected to capacitor C38 and the anode of diode D10. The other end of inductor L7 is connected to the other end of capacitor C38, the cathode of diode D10, one end of resistor R47, and the anode of diode D9. The other end of resistor R47 is connected to the cathode of diode D11. The cathode of diode D9 is connected to the collector of transistor Q9. The emitter of transistor Q9 is connected to one end of capacitor C39 and one end of capacitor C40. The other end of capacitor C39 and capacitor C40 are connected in parallel to ground. The other end of capacitor C40 is connected to one end of resistor R50, one end of capacitor C36, resistor R49, and one end of capacitor C41. The other end of capacitor C36 is connected to one end of inductor L8 and chip U5. The other end of inductor L8 is connected to the other end of resistor R49, one end of capacitor C41, and one end of capacitor C42. The other end of capacitor C41 is connected to the other end of resistor R49, chip U5, and resistor R50. The other end of capacitor C42 and the other end of resistor R50 are grounded.

[0035] In this embodiment, as Figure 5As shown, the power module also includes an LDO circuit connected to the DC-DC conversion circuit. The LDO circuit includes a chip U6, resistors R51, R52, and R53, and capacitors C43, C44, C45, and C46. One end of resistor R51 is connected to capacitor C46 and chip U6, and the other end of resistor R51 is connected to one end of capacitor C45. The other end of capacitor C45 is connected to the other end of capacitor C46, ​​chip U6, one end of resistor R53, and one end of capacitor C43. Resistor R53 is connected to one end of capacitor C44 and one end of resistor R52. The other end of capacitor C44 is connected to the other end of resistor R52 and one end of capacitor C43, and is connected to chip U6. Capacitor C43 is connected to... The power module also includes a Boost converter circuit, resistors R72, R73, R74, R75, R76, R77, R78, and R79, capacitors C73, C74, C75, C76, C77, and C78, ​​inductors L17 and L18, MOSFET Q13, and switching diode D14. Inductor L18 is connected to one end of resistor R72. The other end of resistor R72 is connected to one end of capacitor C73, one end of capacitor C74, and one end of inductor L17. The other end of capacitor C73 is connected to the other end of capacitor C74 and grounded. The other end of inductor L17 is connected to the drain of MOSFET Q13 and the power input terminal of switching diode D14. Switching diode D14 is connected to one end of capacitor C75 and one end of resistor R73. The other end of resistor R73 is connected to one end of capacitor C76 and... One end of resistor R74, one end of capacitor C77, and one end of resistor R75 are connected. The other end of resistor R75 is connected to one end of resistors R79 and R77. The other ends of capacitors C75, C76, R79, and C77, and the source of MOSFET Q13 are grounded. The gate of MOSFET Q13 is connected to one end of resistors R76, C78, ​​and R78. The other end of capacitor C78 is connected to the other end of resistor R78 and grounded. SGM61412AXTN6G is a DC-DC power supply chip. The SGM61412 is a high-frequency synchronous buck converter with integrated switching. It can provide up to 1.2A of current to the output over a wide input voltage range of 4.5V to 42V. It is suitable for various high input voltage industrial applications or for power conditioning of unregulated power supplies. SGM2046-ADJXG indicates a linear regulator (LDO).

[0036] Optionally, the power module further includes a Boost converter circuit connected to the main control unit. The Boost converter circuit includes resistors R72, R73, R74, R75, R76, R77, R78, and R79; capacitors C73, C74, C75, C76, C77, and C78; inductor L17; inductor L18; MOSFET Q13; and switching diode D14. Inductor L18 is connected to one end of resistor R72. The other end of resistor R72 is connected to one end of capacitor C73, one end of capacitor C74, and one end of inductor L17. The other end of capacitor C73 is connected to the other end of capacitor C74 and grounded. The other end of inductor L17 is connected to the drain of MOSFET Q13 and the power input terminal of switching diode D14. Switching diode D14 is connected to one end of capacitor C75 and one end of resistor R73. The other end of resistor R73 is connected to one end of capacitor C76 and... One end of resistor R74, one end of capacitor C77, and one end of resistor R75 are connected. The other end of resistor R75 is connected to one end of resistors R79 and R77. The other ends of capacitors C75, C76, R79, and C77 are connected to the source of MOSFET Q13 and grounded. The gate of MOSFET Q13 is connected to one end of resistors R76, C78, ​​and R78. The other end of capacitor C78 is connected to the other end of resistor R78 and grounded.

[0037] In this embodiment, as Figure 6 As shown, the Boost circuit also includes capacitors C81, C82, C83, C84, C85, C86, and C87, resistors R80, R81, and R82, inductors L19, L20, and L21, and transistor Q14. One end of capacitor C79 is connected to capacitor C80 and grounded. The other end of capacitor C79 is connected to the other end of capacitor C80 and one end of inductor L19. Inductor L19 is connected to one end of inductor L20, capacitor C82, and transistor Q14. The base of transistor Q14 is connected to one end of resistor R80 and one end of capacitor C84. The other end of resistor R80 is connected to one end of capacitor C83 and one end of resistor R81. The other end of capacitor C84 is connected to one end of inductor L21 and one end of capacitor C85. The other end of capacitor C85 is connected to one end of resistor R82 and one end of capacitor C86. The other end of capacitor C86 is connected to one end of capacitor C87 and the APD receiver module. The other end of inductor L20 is connected to capacitor C81. The other end of capacitor C82, the emitter of transistor Q14, the other end of capacitor C83, the other end of inductor L21, the other end of resistor R82, and the other end of capacitor C87 are grounded. The resistor R76 (HV_PWM) in the Boost converter circuit is connected to the main control unit.

[0038] like Figure 4As shown, the control module includes a display unit P1, a control unit U1F, a button unit, a communication interface, and a programming unit. The control unit is an MCU, connected to multiple resistors, multiple capacitors in parallel, and an inductor. The MCU selected is GD32F425 (which can be written as GD32F425Vx). It mainly realizes the control, communication, and data processing of various peripheral devices of the system. Peripheral devices include programming and communication interfaces, external buttons, displays, etc., to complete functions such as program programming, serial communication debugging, input / output, and distance measurement result display. In addition, the ITOF phase-method laser displacement sensor provided by this invention has the following characteristics: Dual-optical-path design: By working together with the external and internal lasers, more stable measurement and reference signals are provided, improving ranging accuracy and reliability; The hardware architecture integrates "electrical heterodyne mixing detection + dual-optical-path real-time calibration": it generates a highly stable coherent master oscillator and local oscillator signal pair through MS5351, and uses the nonlinearity of APD to perform photoelectric heterodyne mixing, transforming the high-frequency measurement problem into low-frequency high-precision measurement; combined with the dual-optical-path switching design, it measures in real time and subtracts the inherent delay and drift of the system, realizing self-calibration and high environmental adaptability at the hardware level. Optimized balance between system cost and performance: By cleverly converting high-frequency problems into low-frequency processing, the performance requirements of core components such as ADCs are reduced, thus controlling the overall system cost while achieving high performance.

[0039] High-precision ranging: Within a range of 0.05 - 10m, the repeatability reaches ±3mm, which is a significant improvement compared to existing technologies; Strong anti-interference capability: Through optical path and blind spot compensation design, the light receiving capability in complex environments is effectively enhanced and the blind spot of ranging is reduced, thereby improving the accuracy and reliability of ranging. Range expansion capability: While maintaining the basic optical structure and hardware design, the ranging range can be gradually expanded to 20m, 30m, 50m, etc., to meet the needs of different users.

[0040] It should be noted that, regarding optical path structure replacement: a dual-optical-path structure is the preferred solution of this invention, but in certain specific application scenarios, a single-optical-path structure can also be considered, with improved anti-interference capability and measurement accuracy achieved through optimized signal processing algorithms. Regarding signal processing algorithm replacement: this invention employs digital signal processing and algorithms, but in practical applications, other advanced signal processing algorithms, such as wavelet transform and Kalman filtering, can be selected according to specific needs to further improve signal quality and ranging accuracy.

[0041] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An ITOF phase-based laser displacement sensor, characterized in that, The laser displacement sensor includes a power module, a control module, a scale signal generation module, a laser drive module, and an APD receiving module. The power module and the APD receiving module are both connected to the control module, and the scale signal generation module and the APD receiving module are both connected to the laser drive module. The laser driving module includes a first laser unit and a second laser unit, and the control module includes a main control unit and a sampling unit. The main control unit and the sampling unit are both connected to the APD receiving module, and the laser driving module is connected to the main control unit. The main control unit is used to receive multiple sets of measuring scale frequency pairs generated by the measuring scale signal generation module, and control the first laser unit and the second laser unit to measure each set of measuring scale frequency pairs to obtain the corresponding ranging signal and reference signal. The main control unit controls the sampling rate of the sampling unit according to the frequency difference between the ranging signal and the reference signal. The sampling unit is used to sample the sinusoidal voltage signal output by the APD receiving module according to the sampling rate to obtain multiple sampling sequences. The main control unit performs phase ranging calculation on each of the sampling sequences according to the difference frequency to obtain the target distance of each set of measuring frequency pairs.

2. The ITOF phase-based laser displacement sensor according to claim 1, characterized in that, Each set of measuring frequency pairs includes a first frequency and a second frequency. The main control unit uses the Geertz algorithm to calculate the difference frequency between the second frequency and the first frequency. Complex spectral values ​​at corresponding frequency points And based on the complex spectrum value Calculate the phase of the external optical path signal corresponding to the first laser unit and the phase of the internal optical path signal corresponding to the second laser unit, as well as the phase difference under the current measuring scale. The corresponding expressions are: （1） The main control unit calculates the fuzzy distance under the current measuring scale according to the phase ranging algorithm, and the corresponding expression is: （2） in, The phase of the external optical path signal. Let c be the phase of the signal in the internal optical path, and c be the speed of light. The current modulation frequency; A set of fuzzy distances is obtained by sequentially calculating the modulation frequencies of multiple sets of measuring scale frequency pairs using formulas (1) and (2); The target distance for each pair of measuring frequency pairs is obtained by combining multiple fuzzy distances using a step-by-step defuzzification algorithm, wherein the first frequency is the frequency of the local oscillator signal, and the second frequency is the frequency of the main oscillator signal or the modulation frequency.

3. The ITOF phase-based laser displacement sensor according to claim 2, characterized in that, The measuring signal generation module includes chip U7, resistors R54, R55, R56, R57, R58, R59, R60, R61, capacitors C47, C48, C49, C50, C51, C52, inductors L9, L10, L11, L12, and MOSFET Q10; Capacitors C48 and C49 are connected in parallel to chip U7 and one end of inductor L11. One end of capacitor C50, one end of resistors R57, R58, R59, and R60 are all connected to chip U7. Resistors R56 and R61 are connected to the other end of capacitor C50. The other end of resistor R59 is connected to the other end of resistor R60. One end of resistor R54, one end of capacitor C47, and the gate of MOSFET are all connected to resistor R55. The other end of resistor R54 is connected to inductor L10, the other end of capacitor C47, and the source of MOSFET Q10. The other ends of inductors L9 and L11 are both connected to the drain of MOSFET Q10. The other end of resistor R57 is connected to the laser driver module. The other end of resistor R58 is connected to the APD receiver module. Capacitors C51 and C52 are connected to chip U7 and inductor L12.

4. The ITOF phase-based laser displacement sensor according to claim 3, characterized in that, The laser driving module also includes an analog switch U8, capacitors C53, C54, C55, C56, C57, C58, C59, C60, C61, C62, C63, C64, C65, C66, C67, C68, C69, C70, C71, C72, C107, C108, C109, C110, inductors L13, L14, L15, transistors Q11 and Q12, and a comparator U9. Inductor L13 is connected to capacitors C53, C60, one end of inductor L14, capacitors C54, C61, chip U8, capacitors C110, C55, C56, the first laser unit, the second laser unit, capacitors C57, C58, C59, and C108. Capacitors C100, C55, and C56 are connected in parallel, as are capacitors C57, C58, C59, and C108. Inductor L1...

4. The other end of capacitor C62 is connected to one end of capacitor C6 and the collector of transistor Q11. The other end of capacitor C62 is connected to analog switch U8 and one end of inductor L15. The base of transistor Q11 is connected to one end of resistor R64, one end of capacitor C70, and one end of capacitor C66. The other end of capacitor C66 is connected to one end of capacitor C68 and one end of capacitor C65. The other end of capacitor C65 is connected to capacitor C67. The other end of capacitor C67 is connected to the other end of capacitor C68. Capacitor C7... The other end of the transistor Q11 is grounded, the other end of the inductor L15 is connected to the collector of the transistor Q12, the emitter of the transistor Q12 is connected to the resistor R71, the base of the transistor Q12 is connected to one end of the resistor R67, the other end of the resistor R67 is connected to one end of the capacitor C64 and the output of the comparator U9, the positive input of the comparator U9 is connected to one end of the capacitor C71 and one end of the resistor R68, the capacitor C69 and the capacitor C109 are connected in parallel to the comparator U9, the negative input of the comparator U9 is connected to the other end of the capacitor C64, the resistor R65 and the resistor R66, the other end of the resistor R68 is connected to one end of the resistor R70, one end of the capacitor C72 and the resistor R69, and the other end of the capacitor C71, the other end of the resistor R70 and the other end of the capacitor C72 are grounded. The first laser unit includes an external optical path laser tube connected to the analog switch U8, and the second laser unit includes an internal optical path laser tube connected to the analog switch U8.

5. The ITOF phase-based laser displacement sensor according to claim 3, characterized in that, The APD receiving module includes resistors R83, R84, R85, R86, R87, R88, R89, R90, R91, R92, R93, R94, and R95; capacitors C88, C89, C90, C91, C92, C93, C94, C95, C96, C97, C98, C99, C100, C101, C102, and C103; comparator U10; operational amplifier U11A; and operational amplifier U11B. Resistor R83 is connected to one end of capacitors C89, C91, and C93, one end of resistor R87, and the positive input terminal of comparator U10. The other end of capacitor C89 is connected to the other ends of capacitors C91 and C93, and the other end of resistor R87. One end of resistor R90 is connected to one end of capacitors C99 and C95, one end of capacitor C103, and the negative input terminal of comparator U10. The other end of resistor R90 is connected to one end of capacitor C98. The other end of C98 is connected to the other end of capacitor C99 and grounded. The other end of resistor R95 is connected to the other end of capacitor C103, one end of resistor R88, and the output of comparator U10. Resistor R84 is connected to one end of capacitor C92, one end of capacitor C94, and comparator U10. The other end of capacitor C92 is connected to the other end of capacitor C94 and grounded. The other end of resistor R88 is connected to one end of resistor R89 ​​and one end of capacitor C97. The other end of resistor R89 ​​is connected to one end of capacitor C95. One end of capacitor C88 is connected; the other end of capacitor C95 is connected to one end of resistor R85 and the negative input terminal of op-amp U11A; the other end of resistor R88 is connected to the other end of resistor R85, the output terminal of op-amp U11A, and one end of resistor R91; one end of capacitor C100 is connected to one end of resistor R92; the other end of resistor R92 is connected to one end of resistor R94, one end of capacitor C101, the positive input terminal of op-amp U11A, and the positive input terminal of op-amp U11B; the other end of resistor R94... One end of the capacitor is connected to the other end of capacitor C101 and grounded. The other end of capacitor C100 is grounded. The other end of resistor R91 is connected to one end of capacitor C96 and one end of capacitor C90. The other end of capacitor C96 is connected to the negative input terminal of op-amp U11B and one end of resistor R86. The other end of capacitor C90 is connected to the other end of resistor R86, the output terminal of op-amp U11B, and one end of resistor R93. The other end of resistor R93 is connected to one end of capacitor C102. The other end of capacitor C102 is grounded.

6. The ITOF phase-based laser displacement sensor according to claim 1, characterized in that, The power module includes a DC-DC converter circuit, which includes chip U5, resistors R47, R48, R49, and R50, capacitors C37, C38, C39, C40, C41, and C42, inductors L7 and L8, diodes D9, D10, and D11, and transistor Q9. One end of resistor R48 is connected to one end of capacitor C37 and inductor L7. The other end of capacitor C37 is connected to capacitor C38 and the anode of diode D10. The other end of inductor L7 is connected to the other end of capacitor C38, the cathode of diode D10, one end of resistor R47, and the anode of diode D9. The other end of resistor R47 is connected to the cathode of diode D11. The cathode of diode D9 is connected to the collector of transistor Q9. The emitter of transistor Q9 is connected to one end of capacitor C39 and one end of capacitor C40. The other end of capacitor C39 and capacitor C40 are connected in parallel to ground. The other end of capacitor C40 is connected to one end of resistor R50, one end of capacitor C36, resistor R49, and one end of capacitor C41. The other end of capacitor C36 is connected to one end of inductor L8 and chip U5. The other end of inductor L8 is connected to the other end of resistor R49, one end of capacitor C41, and one end of capacitor C42. The other end of capacitor C41 is connected to the other end of resistor R49, chip U5, and resistor R50. The other end of capacitor C42 and the other end of resistor R50 are grounded.

7. The ITOF phase-based laser displacement sensor according to claim 6, characterized in that, The power module also includes an LDO circuit connected to the DC-DC conversion circuit. The LDO circuit includes a chip U6, resistors R51, R52, and R53, and capacitors C43, C44, C45, and C46. One end of resistor R51 is connected to capacitor C46 and chip U6, and the other end of resistor R51 is connected to one end of capacitor C45. The other end of capacitor C45 is connected to the other end of capacitor C46, ​​chip U6, one end of resistor R53, and one end of capacitor C43. Resistor R53 is connected to one end of capacitor C44 and one end of resistor R52. The other end of capacitor C44 is connected to the other end of resistor R52 and one end of capacitor C43, and is connected to chip U6. Capacitor C43 is also connected to the LDO circuit.

8. The ITOF phase-based laser displacement sensor according to claim 7, characterized in that, The power module also includes a Boost converter circuit connected to the main control unit. The Boost converter circuit includes resistors R72, R73, R74, R75, R76, R77, R78, and R79; capacitors C73, C74, C75, C76, C77, and C78; inductors L17 and L18; MOSFET Q13; and switching diode D14. Inductor L18 is connected to one end of resistor R72. The other end of resistor R72 is connected to one end of capacitor C73, one end of capacitor C74, and one end of inductor L17. The other end of capacitor C73 is connected to the other end of capacitor C74 and grounded. The other end of inductor L17 is connected to the drain of MOSFET Q13 and the power input terminal of switching diode D14. Switching diode D14 is connected to one end of capacitor C75 and one end of resistor R73. The other end of resistor R73 is connected to one end of capacitor C76 and... One end of resistor R74, one end of capacitor C77, and one end of resistor R75 are connected. The other end of resistor R75 is connected to one end of resistors R79 and R77. The other ends of capacitors C75, C76, R79, and C77 are connected to the source of MOSFET Q13 and grounded. The gate of MOSFET Q13 is connected to one end of resistors R76, C78, ​​and R78. The other end of capacitor C78 is connected to the other end of resistor R78 and grounded.

9. The ITOF phase-based laser displacement sensor according to claim 8, characterized in that, The Boost circuit also includes capacitors C81, C82, C83, C84, C85, C86, and C87, resistors R80, R81, and R82, inductors L19, L20, and L21, and transistor Q14. One end of capacitor C79 is connected to capacitor C80 and grounded. The other end of capacitor C79 is connected to the other end of capacitor C80 and one end of inductor L19. Inductor L19 is connected to one end of inductor L20, capacitor C82, and transistor Q14. The base of transistor Q14 is connected to one end of resistor R80 and one end of capacitor C84. The other end of resistor R80 is connected to one end of capacitor C83 and one end of resistor R81. The other end of capacitor C84 is connected to one end of inductor L21 and capacitor C82.

5. Connect one end of capacitor C85 to one end of resistor R82 and one end of capacitor C86. Connect the other end of capacitor C86 to one end of capacitor C87 and the APD receiver module. Connect the other end of inductor L20 to one end of capacitor C81. Connect the other end of capacitor C81 to resistor R74. Connect the other end of capacitor C82, the emitter of transistor Q14, the other end of capacitor C83, the other end of inductor L21, the other end of resistor R82, and the other end of capacitor C87 to ground.

10. The ITOF phase-based laser displacement sensor according to claim 1, characterized in that, The laser displacement sensor also includes a peripheral device module connected to the main control unit. The peripheral device module includes at least one of a programming and communication interface, an external button, or a display screen. The main control unit includes an MCU of model GD32F425.

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