Sensor light spot collimation debugging method

Abstract

The invention belongs to the technical field of sensors, and discloses a sensor light spot collimation debugging method, which comprises the following steps: S1, establishing a reference corresponding relation of relative poses between an output signal of a four-quadrant photoelectric detector and a transmitting assembly consisting of a laser and a collimating lens; s2, acquiring an electric signal output by the four-quadrant photoelectric detector due to the change of the position of the incident light spot in real time, and judging the deviation between the current pose and the target pose of the transmitting assembly based on the reference corresponding relation and the current electric signal; and S3, according to the deviation, generating a control instruction to drive an execution mechanism to adjust the pose of the transmitting assembly, so that the deviation is reduced until a preset collimation requirement is met. According to the invention, the position of the light spot of the emission assembly composed of the laser and the collimating lens can be automatically adjusted, so that the collimation debugging of the emission light path of the sensor can be completed without depending on artificial experience judgment, and the production line debugging efficiency and the product consistency can be obviously improved on the premise of ensuring the debugging precision and repeatability.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, and in particular relates to a method for adjusting the collimation of sensor spot. Background Technology

[0002] In the manufacturing process of laser rangefinder sensors, especially those based on the triangulation principle, the collimation adjustment of the laser emission assembly (usually composed of a laser and a collimating lens) is a critical step. Collimation directly determines the parallelism of the beam and the consistency of the beam size, which has a decisive impact on the measurement accuracy and range performance of the sensor.

[0003] Currently, the industry commonly uses a mechanical debugging platform built on a high-precision displacement slide table for this type of debugging. The general procedure is as follows: the laser and lens are initially installed on the slide table, and technicians visually observe the shape of the light spot projected onto a distant screen or detector after exiting the lens. At the same time, they manually adjust multiple dimensions of the slide table (usually including an axial slide table to control the distance between the laser and the lens, and an adjustment frame to control the pitch and deflection angles of the laser) in an attempt to make the light spot reach the predetermined size and center position.

[0004] This manual debugging method has several inherent drawbacks: First, it is highly dependent on the operator's skill level and experience, resulting in inconsistent debugging quality and poor stability. Second, the debugging process is cumbersome and time-consuming, requiring the operator to alternately observe and adjust multiple degrees of freedom, leading to high production time per unit and severely restricting production efficiency. Finally, because it involves manual judgment and operation, it is difficult to guarantee the consistency of performance between products, resulting in poor batch stability and hindering large-scale standardized production.

[0005] Therefore, there is an urgent need in this field for a sensor spot collimation adjustment method to solve the above-mentioned technical problems. Summary of the Invention

[0006] In view of this, the present invention provides a method for adjusting the collimation of sensor spot, in order to solve the problems of low efficiency, high labor cost per unit, and difficulty in ensuring product consistency caused by excessive reliance on manual experience in the adjustment process in the prior art.

[0007] To address the aforementioned technical problems, this invention provides a method for adjusting the collimation of a sensor spot, comprising the following steps: S1: Establish a reference correspondence between the output signal of the four-quadrant photodetector and the relative pose of the emission assembly composed of the laser and collimating lens; S2: Real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and based on the reference correspondence and the current electrical signal, determination of the deviation between the current pose of the transmitting component and the target pose; S3: Based on the deviation, generate control commands to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until the preset collimation requirement is met.

[0008] Optionally, establishing a reference correspondence between the output signal of the four-quadrant photodetector and the relative pose of the transmitting assembly composed of the laser and collimating lens includes: Initial optical path alignment is performed so that the laser beam emitted from the laser shines onto the photosensitive surface of the four-quadrant photodetector after passing through the collimating lens. Adjust the axial distance between the laser and the collimating lens, and measure the spot size at the photosensitive surface. When the spot size reaches a preset value, record the total electrical signal value output by the four-quadrant photodetector at this time as the total light intensity reference value. Adjust the pitch and azimuth angles of the laser so that the centroid of the light spot coincides with the center of the photosensitive surface, and record the output signal characteristics in the four quadrants at this time.

[0009] Optionally, in the real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and in determining the deviation between the current pose and the target pose of the transmitting component based on the reference correspondence and the current electrical signal, the real-time coordinates (x, y) of the light spot centroid are calculated using the following formula: x=k ((V1+V4)-(V2+V3)) / (V1+V2+V3+V4); y=k ((V1+V2)-(V3+V4)) / (V1+V2+V3+V4); Wherein, V1, V2, V3, and V4 are the real-time output signals of the four quadrants, and k is the calibration scaling factor related to the characteristics of the four-quadrant photodetector.

[0010] Optionally, the step of acquiring the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot in real time, and determining the deviation between the current pose of the transmitting component and the target pose based on the reference correspondence and the current electrical signal; includes: Based on the calculated real-time coordinates (x, y) and the known distance f from the optical center of the collimating lens to the photosensitive surface, the elevation angle α and azimuth angle β, which characterize the beam direction deviation, are calculated: α = arctan(x / f); β = arctan(y / f); The pitch angle deviation α and azimuth angle deviation β directly correspond to the pitch direction and azimuth direction that the laser needs to be adjusted.

[0011] Optionally, the step of generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, includes coaxiality adjustment and focal length adjustment. The coaxiality adjustment includes controlling the actuator to adjust the pitch and azimuth of the laser based on the calculated pitch angle α and azimuth angle β, so as to drive the center of the spot centroid to move towards the center of the photosensitive surface until α and β approach zero; The focal length adjustment includes acquiring the total electrical signal value output by the current four-quadrant photodetector, comparing it with the total light intensity reference value, and controlling the actuator to adjust the axial distance between the laser and the collimating lens according to the comparison result, until the difference between the total electrical signal value and the total light intensity reference value is within the allowable threshold.

[0012] Optionally, the coaxiality adjustment and the focal length adjustment are performed sequentially.

[0013] Optionally, steps S2 and S3 are executed iteratively until the following debugging completion conditions are met simultaneously: The absolute values ​​of the pitch angle α and the azimuth angle β are less than the first threshold. The absolute value of the difference between the total electrical signal value and the total light intensity reference value is less than the second threshold.

[0014] Optionally, the actuator includes a two-dimensional motion module for adjusting the pitch and azimuth angles of the laser, and a one-dimensional motion module for adjusting the axial position of the laser; the control command is sent to the drivers of the two-dimensional motion module and the one-dimensional motion module.

[0015] Optionally, generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, includes: Obtain the deviation signal output by the pose determination step; According to a preset control algorithm, the deviation signal is converted into a drive command for the actuator; The actuator is controlled to act according to the driving command to change the pose of the launching component; After the actuator completes its action, it returns to the pose determination step to obtain a new pose deviation signal. The above process is repeated until the pose deviation signal meets the preset collimation requirement.

[0016] Optionally, after generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, the method further includes: The adjusted pose of the transmitting component is fixed, and the final pose parameters and the output signal of the four-quadrant detector are recorded as an indicator that the product debugging is complete.

[0017] Compared with existing technologies, the present invention provides a sensor spot collimation adjustment method. By introducing a four-quadrant photodetector to detect the centroid position of the spot on the photosensitive surface in real time and accurately, and based on the deviation of this position information from a preset benchmark, the servo system is driven to perform closed-loop automatic adjustment of the laser. This transforms the traditional manual adjustment process, which relies on human experience and repeated trials, into a quantitative and automated precise control process. Compared with existing adjustment methods based on displacement slides and hand-eye coordination, the adjustment method of the present invention can significantly improve adjustment efficiency and consistency, greatly reduce the working time per unit and the dependence on operator experience, and avoid the subjective error of human judgment. It can stably and reliably ensure that mass production products meet uniform performance standards, thereby reducing production costs, increasing product qualification rate, and enhancing large-scale manufacturing capabilities. Attached Figure Description

[0018] Figure 1 This is a flowchart of a sensor spot collimation adjustment method used in an embodiment of the present invention.

[0019] Figure 2 yes Figure 1 A flowchart of step S1. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] To make the description of this disclosure more detailed and complete, illustrative descriptions of embodiments and specific examples of the present invention are provided below; however, these are not the only forms of implementing or utilizing the specific embodiments of the present invention. The embodiments cover features of multiple specific embodiments and the methods, steps, and their order for constructing and operating these specific embodiments. However, other specific embodiments may also be used to achieve the same or equivalent functions and step sequences. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention 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 of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0023] In the description of the embodiments of the present invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The word "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more. Other quantifiers should be understood similarly. The preferred embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0024] like Figure 1 The flowchart described above illustrates a sensor spot collimation adjustment method provided in an embodiment of the present invention, which includes the following steps.

[0025] S1: Establish the reference correspondence between the output signal of the four-quadrant photodetector and the emission assembly composed of the laser and collimating lens.

[0026] Specifically, in this embodiment of the invention, a definite mapping relationship between the output signal and the pose is established by systematically calibrating the initially installed transmitting component and the four-quadrant photodetector. This calibration includes adjusting the axial distance between the laser and the lens (focusing) to make the spot size reach the design value, and adjusting the elevation and azimuth angles of the laser (centering) to make the center of mass of the spot coincide with the center of the detector. The output signal characteristics and total light intensity value of each quadrant of the four-quadrant detector recorded under this ideal state constitute the "zero-position" reference for subsequent judgment of pose deviation. This step transforms the abstract "collimation" requirement into a quantifiable and comparable electrical signal reference, laying the fundamental basis for subsequent automated and quantitative debugging, and eliminating the uncertainty of relying on subjective human judgment in traditional methods.

[0027] S2: Real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and based on the reference correspondence and the current electrical signal, determination of the deviation between the current pose of the transmitting component and the target pose.

[0028] Specifically, in this embodiment of the invention, during the debugging process, minute changes in the actual pose of the transmitting component can cause changes in the angle or focal position of the emitted beam, thereby shifting the position of the light spot illuminating the photosensitive surface of the four-quadrant detector. By acquiring and processing the photocurrent or voltage signals (V1, V2, V3, V4) generated in the four quadrants in real time, and calculating the current precise centroid coordinates of the light spot according to a predetermined algorithm (e.g., the centroid calculation formula), the current precise centroid coordinates of the light spot can be calculated. By comparing this real-time coordinate with the "zero position" reference (center coincidence state) established in step S1, the angular deviation of the current beam in both the pitch and azimuth directions can be quantitatively calculated, or the focal length deviation can be evaluated by comparing the total light intensity with the reference total light intensity. This step achieves real-time, accurate, and objective digital perception of the pose state of the transmitting component, replacing manual visual observation and experience estimation.

[0029] S3: Based on the deviation, generate control commands to drive the actuator to adjust the pose of the launching component, so that the deviation is reduced until the preset collimation requirement is met.

[0030] Specifically, in this embodiment of the invention, the digital deviation value (such as angle error, light intensity difference) calculated in step S2 is used as the input to the control system. The control system converts this deviation signal into corresponding drive commands based on preset control logic (such as a PID algorithm) and sends them to the actuator (such as a high-precision electric displacement stage or rotary stage) that drives the laser's pose. The actuator precisely adjusts the laser's spatial position (axial movement for focusing) and attitude angle (pitch and rotation for centering) according to the commands, thereby actively correcting the pose deviation of the emitting component. This adjustment changes the position of the light spot on the detector, which is then sensed again in step S2, forming a closed-loop control loop of "sensing, judging, executing, and re-sensing." This process iterates until the light spot position and light intensity signal both return to and stabilize within a preset tolerance range, thereby automatically and reliably achieving the collimation adjustment target and realizing a fundamental shift from manual trial and error to system closed-loop self-correction.

[0031] As an optional implementation, please refer to Figure 2 In step S1, establishing the reference correspondence between the output signal of the four-quadrant photodetector and the emission assembly composed of the laser and collimating lens includes: S11: Initial optical path alignment, so that the laser beam emitted from the laser shines on the photosensitive surface of the four-quadrant photodetector after passing through the collimating lens.

[0032] Specifically, in this embodiment of the invention, the laser beam is first ensured to pass approximately through the collimating lens and ultimately fall within the effective photosensitive area of ​​the four-quadrant photodetector. This is a coarse adjustment process aimed at establishing a basic optical path, providing a signal basis for subsequent precise measurements and adjustments. If the beam fails to illuminate the detector, all subsequent electrical signal detection and processing cannot be performed.

[0033] S12: Adjust the axial distance between the laser and the collimating lens, and measure the spot size at the photosensitive surface. When the spot size reaches a preset value, record the total electrical signal value output by the four-quadrant photodetector at this time as the total light intensity reference value.

[0034] Specifically, in this embodiment of the invention, after the optical path is connected, the axial distance between the laser and the collimating lens is finely adjusted (i.e., the laser or lens is moved along the optical axis). Simultaneously, at the location of the photosensitive surface of the four-quadrant detector, a spot size formed after emission through the lens is monitored in real time using measuring tools such as a spot analyzer. Through axial adjustment, the spot size is made to converge and ultimately reach the preset value required by theoretical design or process requirements (e.g., reaching the minimum diffuse spot size corresponding to parallel light). When the spot size meets the standard, it means that the relative positional relationship between the laser emission point and the focal plane of the lens is close to the ideal state (i.e., the focal length relationship in the collimated state). At this time, the total electrical signal value output by the four-quadrant photodetector (e.g., the sum of the four-quadrant photocurrents or the total voltage) is recorded, and this value is defined as the total light intensity reference value. This reference value reflects the total light energy received by the detector at the ideal focal length and will serve as a key comparison standard for determining whether the focal length has shifted during subsequent automatic adjustment.

[0035] S13: Adjust the pitch and azimuth angles of the laser so that the centroid of the light spot coincides with the center of the photosensitive surface, and record the output signal characteristics in the four quadrants at this time.

[0036] Specifically, in this embodiment of the invention, after coarse focus adjustment, the pitch angle (rotation about the horizontal axis) and azimuth angle (rotation about the vertical axis) of the laser are further finely adjusted. The goal of the adjustment is to change the exit direction of the beam so that the centroid of the light spot illuminating the four-quadrant detector precisely coincides with the geometric center of the detector's photosensitive surface. When the centroid is centered, ideally, the light energy received by the four quadrants should be equal, and the output signal should have specific balance characteristics (e.g., V1≈V2≈V3≈V4, or the x,y coordinates calculated according to the centroid formula approach zero). The output signal values ​​or their characteristic vectors (such as ratios or differences) of the four quadrants at this time are recorded. This state is defined as the coaxiality reference state, and the recorded signal characteristics are the zero-position electrical standard for judging whether the beam is concentric with the detector's optical axis.

[0037] Through the standardized calibration process described above—first adjusting the light, then focusing, and finally centering—the physical goal of achieving ideal collimation (i.e., accurate focal length and coaxial beam with the detector) is transformed into a series of precisely measurable, storeable, and reproducible electrical signal reference values ​​(total light intensity reference value, balance state of each quadrant). This provides an indispensable and quantitative basis for judging deviations in step S2 and for closed-loop adjustment in step S3, serving as the premise and cornerstone for the entire automated calibration method. It eliminates the subjectivity inherent in manual calibration, ensuring a consistent and accurate starting reference for each calibration.

[0038] As an optional implementation, in step S2, the real-time coordinates (x, y) of the light spot centroid are calculated using the following formula in the process of acquiring the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and determining the deviation between the current pose and the target pose of the transmitting component based on the reference correspondence and the current electrical signal: x=k ((V1+V4)-(V2+V3)) / (V1+V2+V3+V4); y=k ((V1+V2)-(V3+V4)) / (V1+V2+V3+V4); Wherein, V1, V2, V3, and V4 are the real-time output signals of the four quadrants, and k is the calibration scaling factor related to the characteristics of the four-quadrant photodetector.

[0039] Specifically, in this embodiment of the invention, the process of calculating the real-time coordinates (x, y) of the light spot centroid using a formula is the core quantitative calculation in the pose deviation judgment stage. This calculation is based on the physical characteristics and geometric layout of the four-quadrant photodetector, and accurately converts the light intensity distribution sensed in the four quadrants (represented as voltage or current signals V1, V2, V3, V4) into the position information of the light spot energy center in the detector's planar coordinate system.

[0040] The calculation formula is essentially a normalized difference algorithm. Taking the x-coordinate calculation as an example, the numerator (V1+V4)-(V2+V3) represents the imbalance in the intensity distribution of the light spot in the horizontal direction. Here, (V1+V4) is the total intensity signal located on the right side of the coordinate system (first and fourth quadrants), and (V2+V3) is the total intensity signal on the left side (second and third quadrants). The difference between the two directly reflects the degree of left-right offset of the light spot center relative to the vertical center line (y-axis). The denominator (V1+V2+V3+V4) is the total intensity signal in the four quadrants, used to normalize the above difference. This normalization effectively eliminates the influence of total intensity variations caused by laser output power fluctuations or ambient light changes on the position calculation, making the coordinate calculation result only related to the relative position of the light spot and essentially independent of the absolute intensity, thus significantly improving the stability and anti-interference capability of position detection. The calculation principle of the y-coordinate is similar. The molecule (V1+V2)-(V3+V4) reflects the unbalanced distribution of light intensity in the vertical direction of the light spot.

[0041] The scaling factor *k* in the formula is a calibration parameter used to convert the normalized signal difference into physical coordinates with actual length units (such as millimeters or micrometers). The value of *k* is closely related to factors such as the specific dimensions of the photosensitive surface of the four-quadrant detector, the inter-quadrant gap, and the gain of the signal processing circuit. Before practical application, the value of *k* needs to be determined in advance through experimental calibration, for example, by moving a light spot with a known displacement on the detector and recording the corresponding signal changes to calculate the value. Introducing and accurately calibrating the value of *k* ensures that the mapping relationship from electrical signal to spatial position is accurate and traceable, which is a prerequisite for achieving high-precision pose adjustment.

[0042] By performing real-time calculations using the above formula, the system can continuously acquire the precise position of the beam centroid at extremely high speed (depending on the bandwidth of the signal acquisition and processing circuit) and with high accuracy (far exceeding the resolution of the human eye). This digitized position information (x, y) constitutes the most direct and objective input for judging the coaxiality deviation of the transmitting component (i.e., beam pointing deviation). Compared to the traditional method where operators rely on the blurry visual judgment of whether the beam is centered, this invention achieves precise quantitative measurement of the deviation, providing accurate feedback signals for subsequent closed-loop control.

[0043] As an optional implementation, in step S2, the real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and the determination of the deviation between the current pose of the transmitting component and the target pose based on the reference correspondence and the current electrical signal, includes: Based on the calculated real-time coordinates (x, y) and the known distance f from the optical center of the collimating lens to the photosensitive surface, the elevation angle α and azimuth angle β, which characterize the beam direction deviation, are calculated: α = arctan(x / f); β = arctan(y / f); The pitch angle deviation α and azimuth angle deviation β directly correspond to the pitch direction and azimuth direction that the laser needs to be adjusted.

[0044] Specifically, in this embodiment of the invention, the step of calculating the elevation angle α and azimuth angle β based on real-time coordinates (x, y) is a crucial conversion step that transforms the positional offset of the light spot on the detector plane into angular information reflecting the actual pointing deviation of the emitted beam in space. This conversion enables the control system to directly understand and compensate for the directional error of the beam.

[0045] The calculation formulas α=arctan(x / f) and β=arctan(y / f) are based on trigonometric geometry. Here, f is a fixed and known axial distance from the optical center (or equivalent principal point) of the collimating lens to the photosensitive surface of the four-quadrant detector. This relationship assumes that the beam emitted through the collimating lens is ideally parallel (or should be parallel under the target calibration conditions). When the beam has a small pitch or azimuth angle deviation (α, β), this tilted parallel light illuminating the detector plane at a distance f will produce a linear positional offset (x, y). Therefore, by measuring the offset (x, y), the angle (α, β) causing this offset can be calculated. The use of the arctan (arctangent) function ensures that the calculation is accurate even with small angular approximations.

[0046] Distance *f* is a critical system structural parameter. It is typically determined during the system's mechanical design and its precise value is obtained through measurement after assembly. The accuracy of *f* directly affects the accuracy of angle calculations. Substituting it as a known constant into the calculation allows the system to extract spatial angle information from position measurements on a single plane without complex real-time distance measurement, resulting in a simple and efficient method.

[0047] The calculated pitch angle α and azimuth angle β are the most intuitive and direct physical quantities describing the deviation between the current beam direction and the ideal optical axis (i.e., the target direction). These angular deviation values ​​(usually digital quantities in milliradians or degrees) directly correspond to the type and magnitude of attitude adjustment required by the laser. For example, a positive α angle means the beam is deflected upwards, so the control system needs to command the actuator to drive the laser to pitch downwards by the corresponding angle to compensate for this deviation. This step translates the position error into an action command, providing a clear and quantifiable input for the precise and directional adjustment of the actuator in subsequent steps. This makes the entire adjustment process definite in direction and predictable, completely avoiding the problems of blind adjustment and over-adjustment in traditional manual adjustment.

[0048] As an optional implementation, the step of generating control commands based on the deviation to drive the actuator to adjust the pose of the transmitting component, thereby reducing the deviation until a preset collimation requirement is met, including coaxiality adjustment and focal length adjustment.

[0049] The coaxiality adjustment includes controlling the actuator to adjust the pitch and azimuth of the laser based on the calculated pitch angle α and azimuth angle β, so as to drive the center of the spot centroid to move towards the center of the photosensitive surface until α and β approach zero.

[0050] Specifically, in this embodiment of the invention, this stage is dedicated to correcting the directional deviation of the laser beam. The system uses the calculated real-time pitch angle α and azimuth angle β as feedback inputs. These two angle values ​​directly quantify the deviation of the current beam direction from the ideal optical axis. The control system (such as a controller with a built-in PID algorithm) converts this angle deviation into drive commands for the two-dimensional motion module (such as an electric rotary table responsible for pitch and azimuth). The actuator precisely adjusts the laser's attitude according to the commands, with its adjustment direction opposite to the direction of the angle deviation (i.e., negative feedback), aiming to continuously reduce the absolute values ​​of α and β. When both α and β approach zero (i.e., less than a certain set small angle threshold), it means that the beam's output direction is now highly parallel (coaxial) to the optical axis of the four-quadrant detector, and the center of mass of the beam spot is stabilized at the center of the detector. This step solves the problem of where the beam should be directed.

[0051] The focal length adjustment includes acquiring the total electrical signal value output by the current four-quadrant photodetector, comparing it with the total light intensity reference value, and controlling the actuator to adjust the axial distance between the laser and the collimating lens according to the comparison result, until the difference between the total electrical signal value and the total light intensity reference value is within the allowable threshold.

[0052] After coaxiality adjustment and ensuring the beam direction is basically correct, focus adjustment is performed to correct the beam's convergence / divergence. The total light intensity reference value obtained during this stage is used as a reference. The system acquires the total electrical signal value output by the four-quadrant detector in real time (i.e., the sum of the signals from the four quadrants), which is proportional to the total light energy received by the detector. The current total value is compared with the reference value; the difference reflects the change in spot size caused by the deviation of the laser-lens axial distance from the ideal focal length (e.g., inaccurate distance can cause the spot to diverge or converge on the detector, thus changing the light intensity per unit area and the total received energy). Based on the sign and magnitude of the difference, the control system generates instructions to drive a one-dimensional translation stage to move the laser along the optical axis. For example, if the current total signal is less than the reference value, it may mean that the spot is diverging and the energy density is reduced. The system then controls the laser to move towards the lens for fine-tuning until the difference between the total signal value and the reference value falls within a preset allowable threshold. This step solves the problem of whether the beam is collimated (parallel).

[0053] The above technical solution decouples complex multi-degree-of-freedom adjustment into sequential coaxiality and focus adjustments, offering significant advantages. First, it simplifies the control logic, avoiding coupling oscillations that may occur with simultaneous adjustment of multiple variables, making the system more likely to achieve stable convergence. Second, it improves debugging efficiency and reliability; adjusting the focus only after the direction is correct avoids the problem of signal loss due to severe beam tilt causing the light spot to partially or completely shift out of the detector's photosensitive area. Finally, it conforms to the inherent logic of optical debugging, ensuring correct optical path pointing first, then optimizing the focus state—an optimal engineering practice path.

[0054] As an optional implementation, the coaxiality adjustment and the focal length adjustment are performed sequentially.

[0055] Specifically, in this embodiment of the invention, the sequential execution of coaxiality adjustment and focal length adjustment means that during the closed-loop debugging process, the system completes the alignment tasks of the two dimensions sequentially according to a clear logical order, rather than adjusting them simultaneously or alternately in a disorderly manner. This execution strategy is the core process design to ensure stable, efficient, and reliable convergence of the debugging process.

[0056] The sequential execution is manifested as a pre-defined, automated program flow. After initiating automatic debugging, the system first enters the coaxiality adjustment stage. In this stage, the system focuses on the angle deviation closed-loop control described in claim 5, temporarily freezing or ignoring the focus adjustment channel. Only when the coaxiality adjustment meets the completion conditions (such as the absolute values ​​of α and β being less than the first threshold) will the system logic automatically switch to the focus adjustment stage. In the focus adjustment stage, the system focuses on closed-loop control based on the total light intensity deviation. At this time, the pitch and azimuth attitude of the laser are usually locked or only slightly maintained, mainly driving axial movement for focusing.

[0057] The core advantage of sequential execution lies in its effective decoupling of mutual interference between control variables. Changes in the laser's attitude (pitch / azimuth) not only alter the beam direction but may also slightly change the optical path length or the energy distribution of the beam spot on the detector, thus disturbing the focus determination based on total light intensity. Conversely, axial focusing may also cause a slight additional beam deflection due to mechanical errors. If simultaneous adjustments are made, the control system needs to handle a complex, strongly coupled multivariate problem; the algorithm is complex, prone to oscillations, and difficult to stabilize quickly. Sequential execution decomposes the multivariate control problem into two sequential single-variable (or weakly coupled bivariate) control problems, greatly simplifying the control complexity and improving the convergence speed and stability of each adjustment stage.

[0058] First, coaxiality adjustment is performed to ensure that the light beam is stably illuminating the central region of the four-quadrant detector before entering the fine-tuning focus stage. This avoids the risk of some light spots falling outside the detector's photosensitive area due to severe beam deviation from the center, which could cause abnormal total light intensity signals or centroid calculation failures, thus ensuring the integrity and effectiveness of the feedback signal in the subsequent focus adjustment stage. This is a robust design that proceeds "coarsely before finely" and "ensures the signal before optimizing parameters."

[0059] The clearly defined sequence of execution provides a clear and programmable process flow for fully or semi-automatic commissioning stations on the production line. Robotic arms or automated fixtures can sequentially coordinate to complete different stages of clamping, measurement, and execution actions. Operators or the host computer monitoring system can also clearly understand the current stage and progress of the commissioning process.

[0060] As an optional implementation, steps S2 and S3 are executed iteratively until the following debugging completion conditions are met simultaneously: The absolute values ​​of the pitch angle α and the azimuth angle β are less than the first threshold. The absolute value of the difference between the total electrical signal value and the total light intensity reference value is less than the second threshold.

[0061] Specifically, in this embodiment of the invention, steps S2 and S3 are executed iteratively and set explicit debugging completion conditions. This is the core control logic and termination mechanism for the entire method to achieve fully automatic, adaptive, and precise debugging. It defines a dynamic and intelligent adjustment process and provides quantifiable and objective completion standards.

[0062] The iterative execution described is not a simple repetition, but rather constitutes a typical negative feedback closed-loop control system. Each cycle includes a complete process from "sensing (S2: acquiring signals, calculating deviations) to decision-making and execution (S3: generating commands, driving adjustments)". The action of the actuator (S3) changes the physical pose of the transmitting component, and this change is immediately sensed by the four-quadrant detector (S2) and generates a new signal. The new deviation calculated by the new signal drives a new adjustment. This cycle repeats, forming a real-time or near-real-time (determined by the system sampling and control cycle) dynamic adjustment loop. This structure enables the system to automatically track and compensate for pose deviations caused by various factors (such as mechanical loosening, temperature drift, initial installation errors), ultimately driving and stabilizing the system state within the target range. This completely replaces the traditional open-loop, discrete mode of "manual adjustment once, observation once, and then deciding how to adjust next time" that relies on human judgment.

[0063] This invention sets two conditions for commissioning completion that must be met simultaneously, which correspond to the two core objectives of commissioning: beam direction (coaxiality) and beam quality (focal length / collimation).

[0064] The absolute values ​​of the pitch angle α and the azimuth angle β are less than the first threshold. This condition ensures that the beam pointing accuracy meets the requirements. The first threshold (e.g., 0.1 milliradians) is a very small angle value determined by back-calculation based on the sensor's final application performance indicators (such as ranging linearity and spot offset tolerance). When both α and β are less than this threshold, the parallelism between the beam and the system's optical axis is considered to meet higher-order requirements.

[0065] The absolute value of the difference between the total electrical signal value and the total light intensity reference value is less than the second threshold. This condition ensures that the laser is at the optimal position of the collimating lens focus. The second threshold (e.g., ±0.5% of the reference value) is a tolerance determined based on the allowable range of spot size variation. Meeting this condition means that at the current detection surface, the spot size has stabilized near the preset value, and the beam collimation meets the standard.

[0066] The above technical solution achieves fully automatic termination by setting completion conditions. The system automatically judges these two conditions after each iteration. The loop terminates only when both conditions are met simultaneously, and the debugging is completed automatically. No manual intervention is needed to determine "whether it's adjusted correctly," achieving true automation. The requirement for simultaneous satisfaction avoids situations where "the angle is adjusted correctly but the focus is damaged," or vice versa, ensuring the overall optimality of the debugging results, which is crucial for producing highly consistent products. The thresholds (first threshold, second threshold) are objective and uniform quality standards pre-set according to product specifications. All products adhere to this standard, fundamentally guaranteeing high consistency between batches and eliminating the subjective "feeling" differences inherent in manual debugging. The system judges and adjusts at a very high frequency, enabling rapid convergence. It stops immediately once the conditions are met, avoiding unnecessary over-adjustment or under-adjustment, improving debugging efficiency and ensuring the reliability of the results.

[0067] As an optional implementation, the actuator includes a two-dimensional motion module for adjusting the pitch and azimuth angles of the laser, and a one-dimensional motion module for adjusting the axial position of the laser; the control command is sent to the drivers of the two-dimensional motion module and the one-dimensional motion module.

[0068] Specifically, in this embodiment of the invention, the actuator is specifically defined, clarifying the key physical entities and their division of labor upon which the function of adjusting the pose of the launching component depends. This definition clearly maps the control logic at the method level to the execution unit at the hardware level, forming a complete "control and execution" system.

[0069] The actuator is specifically divided into two functionally distinct and independent motion modules: a two-dimensional motion module, which is dedicated to adjusting the laser in the angular domain, i.e., adjusting its pitch and azimuth angles. It is typically composed of two high-precision rotary stages (such as a pitch stage and an azimuth stage) orthogonally combined, or an integrated two-axis oscillating stage. Its physical motion directly corresponds to correcting beam pointing deviations (i.e., coaxiality issues).

[0070] The one-dimensional motion module is specifically designed to achieve axial adjustment of the laser in the position domain, i.e., moving it back and forth along the optical axis. It is typically a high-precision linear translation stage. Its physical motion directly corresponds to adjusting the relative distance between the laser and the collimating lens to correct focal length deviations.

[0071] This division reflects the design philosophy of functional decoupling. Two-dimensional modules address orientation, while one-dimensional modules address position; both are relatively independent in terms of mechanical structure and control commands. This simplifies mechanical design, control algorithms, and fault diagnosis. Simultaneously, the modular design facilitates integration with standardized, high-precision commercial motion platforms, improving system reliability, maintainability, and upgradeability.

[0072] The control commands are sent to the drivers of the two-dimensional motion module and the one-dimensional motion module. This specifies the exact path from generating control commands to producing physical motion: digital or analog commands generated by the control unit (such as a motion control card or PLC) are sent to the drivers (or motor controllers) of the corresponding motion modules via a bus (such as EtherCAT or a pulse direction interface). The drivers convert the commands into the current or pulse signals required to drive the motors (such as servo motors or stepper motors), ultimately driving the motion modules to produce precise displacement or rotation.

[0073] As an optional implementation, generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, includes: Obtain the deviation signal output by the pose determination step; According to a preset control algorithm, the deviation signal is converted into a drive command for the actuator; The actuator is controlled to act according to the driving command to change the pose of the launching component; After the actuator completes its action, it returns to the pose determination step to obtain a new pose deviation signal. The above process is repeated until the pose deviation signal meets the preset collimation requirement.

[0074] Specifically, in this embodiment of the invention, the implementation process of step S3, "closed-loop adjustment," is further refined. It defines a standardized automatic control loop applicable to the adjustment of various deviations (such as coaxiality deviation and focal length deviation), which constitutes the execution engine of the entire debugging method.

[0075] The deviation signal output from the pose determination step is acquired; this step marks the start of the closed loop. The system receives the calculated digital deviation signal output from step S2 (pose determination). This signal is a direct quantization of the pose state; for example, for coaxiality adjustment, it might be the weighted calculated pitch angle α and azimuth angle β; for focal length adjustment, it is the difference ΔV between the current total light intensity and the reference value. This achieves the transformation from physical state perception to processable data.

[0076] According to a preset control algorithm, the deviation signal is converted into a drive command for the actuator. This step is the core decision-making stage of control. The system calculates the received deviation signal based on a preset control algorithm (e.g., proportional, integral, and derivative control algorithm, i.e., PID algorithm). The purpose of this algorithm is to calculate the control quantity that can most effectively and smoothly reduce the deviation based on the current deviation's magnitude, trend, and cumulative history. This control quantity is then converted into a specific drive command that matches the interface protocol of the specific actuator (e.g., a driver for a two-dimensional / one-dimensional motion module), such as the number of pulses, analog voltage values, or bus command words sent to the servo driver.

[0077] Controlling the actuator to move according to the drive command to change the pose of the transmitting component is a closed-loop execution step. The generated drive command is sent to the corresponding actuator driver in real time. The driver drives the motor (such as a servo motor or stepper motor), which in turn drives the mechanical motion module (such as a rotary table or translation table) to produce precise physical displacement or rotation. This action directly changes the pose of the laser relative to the collimating lens, and is a direct means of actively correcting errors.

[0078] After the actuator completes its action, the system returns to the pose determination step to obtain a new pose deviation signal. This step is crucial for closed-loop formation. After the actuator completes its current command action, the system process does not end but automatically returns to step S2, where the current spot signal is reacquired through the four-quadrant detector, and the new pose deviation is recalculated. This ensures that the system adjustment is based on feedback from the latest state, rather than a one-time open-loop action.

[0079] The above process is repeated until the pose deviation signal meets the preset collimation requirement. The "sensing, decision-making, execution, and re-sensing" process will be executed cyclically, forming a dynamic and continuous negative feedback control loop. Each loop aims to further reduce the pose deviation signal. The termination of the loop is not determined by the number of iterations, but by an objective, preset collimation requirement. The loop will only stop when the latest acquired pose deviation signal meets this requirement, signifying the completion of the debugging process.

[0080] As an optional implementation, after generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, the method further includes: The adjusted pose of the transmitting component is fixed, and the final pose parameters and the output signal of the four-quadrant detector are recorded as an indicator that the product debugging is complete.

[0081] Specifically, in this embodiment of the invention, the defined steps are key post-processing operations performed after the closed-loop adjustment is completed and the collimation requirements are met, to ensure that the debugging results are solidified and a traceable record is formed. This step transforms a successful automatic debugging process into a deliverable and verifiable product state.

[0082] The specific implementation of fixing the adjusted pose involves the laser's pose (including precise axial position, pitch angle, and azimuth angle) relative to the collimating lens (which is then in the optimal collimated state) after the debugging cycle terminates due to met conditions. At this point, the system needs to trigger the pose locking mechanism. This is typically achieved through the following methods: controlling a dedicated locking mechanism (such as locking screws or grippers) to secure the laser bracket or related adjustment mechanism; or driving the actuator into a position holding mode (such as enabling the brake on a servo motor); or applying curing adhesive to key mechanical interfaces. The purpose of this operation is to resist pose drift that may be caused by subsequent handling, vibration, or environmental changes, ensuring that the adjusted optical state remains stable before and after assembly into a complete sensor product, thus materializing and preserving the results of automated debugging.

[0083] While or after locking the pose, the system automatically records a set of data uniquely associated with the current optimal collimation state. This data typically includes: final pose parameters: for example, the final coordinates of the actuators (two-dimensional motion modules and one-dimensional motion modules) or encoder readings. These data directly define the spatial position and angle of the laser when collimation is achieved. Final four-quadrant detector output signals: for example, stable four-quadrant voltage values ​​(V1, V2, V3, V4) and total light intensity. These signals directly reflect the detector response when the spot is centered and the size meets specifications. This set of data is stored in association (e.g., bound to the sensor's serial number), forming the product's digital fingerprint or commissioning completion identifier.

[0084] The above technical solutions ensure state solidification and quality preservation. Fixed pose serves as a quality control point in the production process, transitioning from the debugging station to the next assembly station or finished product, preventing the destruction of excellent debugging results due to unforeseen circumstances. They also achieve end-to-end data digitization and traceability, recording parameters so that the final debugging state of each product is no longer a black box, but rather possesses objective and searchable data records. This provides a valuable data foundation for quality traceability, statistical analysis, and process optimization. For example, by analyzing the final parameters of batch products, the stability and consistency of the production process can be assessed; and a foundation for product identification and subsequent applications can be established: the recorded signal data can serve as a reference benchmark for rapid calibration verification or self-diagnosis of the sensor in subsequent use. Pose parameters provide original reference points for possible repairs or readjustments.

[0085] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above embodiments merely illustrate preferred 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 all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for adjusting the collimation of a sensor spot, characterized in that, Includes the following steps: S1: Establish a reference correspondence between the output signal of the four-quadrant photodetector and the relative pose of the emission assembly composed of the laser and collimating lens; S2: Real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and based on the reference correspondence and the current electrical signal, determination of the deviation between the current pose of the transmitting component and the target pose; S3: Based on the deviation, generate control commands to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until the preset collimation requirement is met.

2. The sensor spot collimation adjustment method according to claim 1, characterized in that, The establishment of a reference correspondence between the output signal of the four-quadrant photodetector and the relative pose of the emission assembly composed of the laser and collimating lens includes: Initial optical path alignment is performed so that the laser beam emitted from the laser shines onto the photosensitive surface of the four-quadrant photodetector after passing through the collimating lens. Adjust the axial distance between the laser and the collimating lens, and measure the spot size at the photosensitive surface. When the spot size reaches a preset value, record the total electrical signal value output by the four-quadrant photodetector at this time as the total light intensity reference value. Adjust the pitch and azimuth angles of the laser so that the centroid of the light spot coincides with the center of the photosensitive surface, and record the output signal characteristics in the four quadrants at this time.

3. The sensor spot collimation adjustment method according to claim 2, characterized in that, The real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, based on the reference correspondence and the current electrical signal, determines the deviation between the current pose of the transmitting component and the target pose, and calculates the real-time coordinates (x, y) of the light spot centroid using the following formula: x=k ((V1+V4)-(V2+V3)) / (V1+V2+V3+V4); y=k ((V1+V2)-(V3+V4)) / (V1+V2+V3+V4); Wherein, V1, V2, V3, and V4 are the real-time output signals of the four quadrants, and k is the calibration scaling factor related to the characteristics of the four-quadrant photodetector.

4. The sensor spot collimation adjustment method according to claim 3, characterized in that, The real-time acquisition of the electrical signal output by the four-quadrant photodetector due to the change in the position of the incident light spot, and the determination of the deviation between the current pose of the transmitting component and the target pose based on the reference correspondence and the current electrical signal; includes: Based on the calculated real-time coordinates (x, y) and the known distance f from the optical center of the collimating lens to the photosensitive surface, the elevation angle α and azimuth angle β, which characterize the beam direction deviation, are calculated: α = arctan(x / f); β = arctan(y / f); The pitch angle deviation α and azimuth angle deviation β directly correspond to the pitch direction and azimuth direction that the laser needs to be adjusted.

5. The sensor spot collimation adjustment method according to claim 4, characterized in that, Based on the deviation, control commands are generated to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, including coaxiality adjustment and focal length adjustment. The coaxiality adjustment includes controlling the actuator to adjust the pitch and azimuth of the laser based on the calculated pitch angle α and azimuth angle β, so as to drive the center of the spot centroid to move towards the center of the photosensitive surface until α and β approach zero; The focal length adjustment includes acquiring the total electrical signal value output by the current four-quadrant photodetector, comparing it with the total light intensity reference value, and controlling the actuator to adjust the axial distance between the laser and the collimating lens according to the comparison result, until the difference between the total electrical signal value and the total light intensity reference value is within the allowable threshold.

6. The sensor spot collimation adjustment method according to claim 5, characterized in that, The coaxiality adjustment and the focal length adjustment are performed sequentially.

7. The sensor spot collimation adjustment method according to claim 5, characterized in that, Steps S2 and S3 are executed iteratively until the following debugging completion conditions are met simultaneously: The absolute values ​​of the pitch angle α and the azimuth angle β are less than the first threshold. The absolute value of the difference between the total electrical signal value and the total light intensity reference value is less than the second threshold.

8. The sensor spot collimation adjustment method according to claim 1, characterized in that, The actuator includes a two-dimensional motion module for adjusting the pitch and azimuth angles of the laser, and a one-dimensional motion module for adjusting the axial position of the laser; the control command is sent to the drivers of the two-dimensional motion module and the one-dimensional motion module.

9. The sensor spot collimation adjustment method according to claim 1, characterized in that, The step of generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, includes: Obtain the deviation signal output by the pose determination step; According to a preset control algorithm, the deviation signal is converted into a drive command for the actuator; The actuator is controlled to act according to the driving command to change the pose of the launching component; After the actuator completes its action, it returns to the pose determination step to obtain a new pose deviation signal. The above process is repeated until the pose deviation signal meets the preset collimation requirement.

10. The sensor spot collimation adjustment method according to claim 1, characterized in that, After generating control commands based on the deviation to drive the actuator to adjust the pose of the launching component, thereby reducing the deviation until a preset collimation requirement is met, the method further includes: The adjusted pose of the transmitting component is fixed, and the final pose parameters and the output signal of the four-quadrant detector are recorded as an indicator that the product debugging is complete.

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