A laser disturbance real-time correction method and system

Abstract

The present application relates to the technical field of large shaft alignment measurement, and discloses a laser disturbance real-time correction method and system. In view of the problem that the laser reference line drift caused by the field heat flow and vibration affects the diameter measurement accuracy, after the laser reference line is established, the dynamic drift vector of the end spot is extracted by CMOS; the real-time axial position of each measuring point is obtained by femtosecond ranging, the proportion coefficient is calculated based on the reference distance, and the local two-dimensional drift of the measuring point is linearly mapped; then the drift vector is projected to the diameter direction to obtain the accurate compensation amount, and the original diameter value is corrected. The present application breaks through the limitation that the measurement depends on the absolute stability of the reference line, completely eliminates the system error caused by environmental disturbance by means of dynamic detection and closed-loop compensation mechanism, and greatly improves the alignment measurement accuracy of multi-bearing section equipment.

Description

Technical Field

[0001] This invention relates to the field of large shaft alignment measurement technology, and in particular to a laser disturbance real-time correction method and system. Background Technology

[0002] In industries such as power, energy, shipbuilding, and metallurgy, centerline alignment (centering) of multi-bearing sections in large shafting systems is a crucial step in ensuring the long-term stable operation of equipment. Currently, on-site engineering often employs a method of establishing a laser reference line in conjunction with a diameter measuring device for shaft alignment measurement. Ideally, during this measurement process, the laser reference line should maintain absolute spatial stability at all times, thus providing a unified absolute reference coordinate system for each measuring point.

[0003] However, in actual engineering environments, the laser reference line inevitably experiences dynamic drift due to factors such as continuous interference from heat flux gradients, minor vibrations of mechanical equipment, or micro-displacements of support brackets. This disturbance deviation is amplified as the measurement distance increases. Traditional measurement methods typically ignore this dynamic drift of the laser reference line throughout the measurement cycle, resulting in unknown reference line deviations being mixed into the original diameter measurement data at each measuring point. These deviations cannot be identified or eliminated, ultimately severely impacting the alignment accuracy and engineering quality of large shaft systems. Summary of the Invention

[0004] To address the problem in the prior art where environmental factors cause dynamic drift of the laser reference line, which severely affects the alignment and measurement accuracy of large shaft systems, this invention proposes a real-time laser disturbance correction method and system.

[0005] This invention first provides a real-time laser perturbation correction method, applied to a system including a laser emitting unit, an end CMOS receiving unit, a diameter measuring unit, a femtosecond ranging unit, and a host computer processing unit, comprising the following steps:

[0006] Step A: Establish a laser reference line between the transmitting end and the end end of the shaft system, and acquire the laser at any time using the end CMOS receiving unit. End spot position and initial reference position The terminal drift vector is calculated. ;

[0007] Step B, obtain the diameter measuring device moved to the first... When measuring points, the original diameter value measured by the diameter measuring unit. and the femtosecond ranging unit measured the first Real-time axial distance from the measuring point to the transmitting end ;

[0008] Step C, pair the end drift vectors based on the same timestamp. With real-time axial distance Calculate the proportionality coefficient ,in The calibration reference distance between the transmitter and the receiver is used, and the first step is calculated based on the aforementioned scaling factor. Laser drift estimation vector at the measurement point Step D, obtain the first Unit vector of the diameter direction of the measuring point The laser drift estimation vector Projecting onto the diameter measurement direction yields the compensation amount along that direction. ;

[0009] Step E, the original diameter measurement value Subtract the compensation amount The drift-compensated diameter measurement value is obtained. .

[0010] As a preferred embodiment of the present invention, the pairing process based on the same timestamp in step C specifically includes: using the diameter measurement trigger time as the reference timestamp, searching for the two frames of data closest to that time in the spot data stream output by the end CMOS receiving unit, performing linear interpolation on the spot center coordinates, and obtaining the end drift vector precisely aligned with the diameter measurement time. .

[0011] As a preferred technical solution of the present invention, the reference distance The calibration method includes: setting an end calibration target surface coaxial with its photosensitive surface in front of the end CMOS receiving unit; moving the diameter measuring device to the end calibration position and keeping it stationary, and continuously sampling to obtain a distance sequence through the femtosecond ranging unit; using the median absolute deviation criterion to remove outliers from the distance sequence; calculating the arithmetic mean of the remaining valid samples after removing outliers, and using the result as the reference distance in the configuration parameters. .

[0012] As a preferred embodiment of the present invention, the unit vector of the diameter measurement direction in step D The expression is ,in The angle parameter is uniquely determined by the measuring point number; the calculation formula for the compensation amount is expanded as follows: ,in and These are the terminal drift vectors. In the horizontal and vertical components.

[0013] As a preferred technical solution of the present invention, after obtaining data in steps A and B, the terminal drift vector sequence and the original diameter measurement value sequence required for calculation are subjected to dual preprocessing. The preprocessing process includes: firstly, applying sliding median filtering to the data sequence; then introducing the Hampel criterion to detect residual outliers in the filtered sequence, and replacing the samples identified as outliers with the median of their respective windows.

[0014] The present invention also provides a real-time laser perturbation correction system, comprising:

[0015] The laser emitting unit, located at one end of the axis, is used to emit a reference laser line that propagates along the axis.

[0016] The end CMOS receiving unit is installed at the other end of the axis system. It is used to receive the reference spot formed by the reference laser line, continuously acquire spot images at a set frame rate and extract the center coordinates, and output the end drift vector.

[0017] The diameter measurement unit is used to obtain the original diameter measurement value from the inner surface of the bearing bush at the measurement point to the laser reference line;

[0018] The femtosecond ranging unit uses an independent femtosecond laser optical path to measure the real-time axial distance from the measuring point where the diameter measuring unit is located to the transmitting end;

[0019] The synchronization control and communication unit maintains a globally unified clock, which is used to timestamp the data from the end CMOS receiving unit, the diameter measuring unit, and the femtosecond ranging unit, and encapsulate them into unified timestamp data frames.

[0020] The host computer processing unit is connected to the synchronous control and communication unit. It receives the data frame, calculates the laser drift estimation vector at the measuring point based on the ratio mapping relationship between the real-time axial distance and the calibration reference distance, projects the laser drift estimation vector onto the diameter measurement direction to obtain the compensation amount, and outputs the diameter measurement value after compensation and correction.

[0021] As a preferred technical solution of the present invention, the femtosecond ranging unit and the diameter measuring unit are integrated on the same portable diameter measuring device. At least three femtosecond reflection target points are arranged at non-collinear positions on the diameter measuring device body. The femtosecond ranging unit performs multi-target calculation on the flight time or phase difference of each target point and synchronously outputs the position information of the diameter measuring device along the axial direction, as well as the tilt and rotation attitude information.

[0022] As a preferred embodiment of the present invention, the laser emitting unit uses a laser in the invisible light band. Its output beam is split by a semi-transparent and semi-reflective mirror arranged at the center of the device, and then propagates along the axis to the end CMOS receiving unit through transmission or reflection. The operating wavelength of the laser is matched with the peak response band of the imaging chip of the end CMOS receiving unit.

[0023] As a preferred technical solution of the present invention, when the shaft system under test includes multiple intermediate bearing segments, one or more intermediate CMOS spot detection nodes are added at the middle position of the shaft system, each segment corresponds to a calibration reference distance, and proportional mapping and error compensation calculation are performed independently in each segment.

[0024] As a preferred technical solution of the present invention, it also includes a power supply unit. The power supply unit adopts an industrial-grade regulated power supply module in conjunction with an uninterruptible power supply device, and the output end is equipped with multi-stage filtering and isolation circuits to provide regulated power supply for the laser emitting unit, the end CMOS receiving unit, the diameter measuring unit, the femtosecond ranging unit, the synchronization control and communication unit, and the host computer interface circuit.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This application employs a proportional mapping mechanism combining end-of-line CMOS spot offset detection with femtosecond ranging for precise positioning. This mechanism enables real-time calculation of the dynamic drift of the laser reference line at any measurement point, and the compensation amount in the diameter measurement direction is obtained through two-dimensional vector direction projection. This scheme does not rely on a priori physical models of environmental disturbances, nor does it require the laser reference line to remain absolutely stable during the measurement period. Instead, it directly eliminates the impact of dynamic drift of the reference line caused by environmental disturbances on the diameter measurement results through a closed-loop mechanism of online detection and real-time compensation. This significantly improves the absolute accuracy and on-site anti-interference stability of centering measurements for large-scale multi-axis bearing sections. Attached Figure Description

[0027] Figure 1 The system overall architecture diagram provided for embodiments of the present invention;

[0028] Figure 2 This is a schematic diagram of the geometric relationship of laser reference line perturbation drift ratio mapping provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of a two-dimensional vector correction calculation model provided in an embodiment of the present invention.

[0030] 100. Laser emitting unit; 200. Terminal CMOS receiving unit; 300. Diameter measuring unit; 400. Femtosecond ranging unit; 500. Synchronization control and communication unit; 600. Power supply unit; 700. Host computer processing unit. Detailed Implementation

[0031] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to illustrate the technical concept and implementation of the present invention, and are not intended to limit the scope of protection of the present invention; any equivalent transformations or substitutions made based on the concept of the present invention should be considered to fall within the scope of protection of the present invention.

[0032] like Figure 1 As shown, the system of this invention is generally composed of a laser emitting unit 100, an end-effector CMOS receiving unit 200, a diameter measuring unit 300, a femtosecond ranging unit 400, a synchronization control and communication unit 500, a power supply unit 600, and a host computer processing unit 700. The system establishes a laser reference line along the axis at the engineering site and achieves real-time correction of the diameter measuring data at each measuring point through the coordinated processing of end-effector spot drift detection, femtosecond ranging scaling mapping, and two-dimensional vector projection compensation.

[0033] The laser emitting unit 100 is positioned at one end of the axis, and its core function is to form a highly stable reference laser line propagating along the axis. In this embodiment, the emitting unit uses a laser in the invisible light band as its light source. Its output beam is split by a semi-transparent mirror positioned at the center of the device. One beam propagates along the axis to the end CMOS receiving unit 200 to form a reference spot, while the other beam, or its remaining transmitted energy, is used for installation and calibration. The semi-transparent mirror ensures that the propagation path of the reference laser line along the axis is not blocked by other components on the diameter measuring device, guaranteeing that the end receiving surface always obtains a stable incident spot. The laser's output power and beam divergence angle are selected to ensure that it can form a concentrated, clearly defined spot on the end CMOS photosensitive surface within a working distance of tens of meters, meeting the requirements for sub-pixel-level center extraction accuracy. To reduce environmental stray light interference, the laser's operating wavelength is matched to the peak response band of the end CMOS imaging chip. If necessary, a corresponding narrowband filter is added to the CMOS incident light window to improve the signal-to-noise ratio.

[0034] The CMOS receiving unit 200 is mounted at the other end of the axis, remotely aligned with the laser emitting unit 100. The normal of the photosensitive surface of this unit approximately coincides with the reference laser line, receiving the reference light spot propagating from the emitting end. A CMOS imaging chip sensitive to the reference wavelength is selected, and its pixel size and array scale should meet the following requirements: throughout the entire operating drift range, the light spot always falls within the effective area of ​​the photosensitive surface, and the spot diameter covers a sufficient number of pixels to support the computational accuracy of the sub-pixel centroid algorithm. The CMOS receiving unit continuously acquires light spot images at a set frame rate and extracts the centroid coordinates in real time through onboard processing circuitry, outputting the current center position of the light spot. During the system initialization phase, after the operator aligns the optical paths of the laser transmitter and receiver, the system continuously acquires several frames of spot images and takes the average of their centroid coordinates as the initial reference position. This information is then written into the host computer configuration. Subsequently, during the measurement process, the difference between the spot position at any given time and this reference point constitutes the end-point drift vector. Its components are represented as

[0035]

[0036] This vector reflects the real-time offset of the laser reference line caused by factors such as heat flow, micro-vibration, or micro-displacement of the support.

[0037] In this embodiment, the diameter measuring unit 300 and the femtosecond ranging unit 400 are integrated on the same diameter measuring device, such as... Figure 1 As indicated by markings 300 / 400. The diameter measuring device is a portable device, either handheld or mounted on a guide rail. The measuring operator moves it sequentially to the measuring positions of each bearing section. The diameter measuring unit 300 is responsible for obtaining the radial distance from the inner surface of the bearing to the laser reference line, i.e., the original diameter value. The diameter measurement can be implemented using a contact gauge or a non-contact sensor, with the range and resolution selected based on the nominal size of the bearing and the required alignment accuracy. The femtosecond ranging unit 400 employs an independent femtosecond laser path to simultaneously measure the distance between at least three femtosecond reflective target points arranged on the equipment, thereby calculating the spatial position and attitude parameters of the diameter measuring device relative to the transmitting end. The femtosecond ranging beam and the laser beam used to establish the baseline are not the same beam; they are independent in wavelength and optical path, thus eliminating the problem of mutual obstruction. In the output value of the femtosecond ranging, the distance component along the axial direction is denoted as... This value represents the first The real-time distance from the measuring point to the transmitting end. In this system, the number of target points is set to three or more, distributed at non-collinear positions on the diameter measuring device body. The femtosecond ranging unit performs multi-target calculations on the flight time or phase difference of each target point to obtain not only the position of the device along the axial direction. It can also simultaneously obtain the tilt and rotation attitude information of the device, reserving an interface for the high-precision refinement of the subsequent error model.

[0038] like Figure 2 As shown, the transmitter, the first The measuring points and the terminal receiver are arranged sequentially along the axis, and the reference distance between the transmitter and the terminal receiver is... When the laser reference line is disturbed, the amount of disturbance is not the same at each point, but is distributed approximately linearly along the propagation direction: the closer the measurement point is to the receiving end, the greater its disturbance offset; the closer the measurement point is to the transmitting end, the smaller the offset. This geometric relationship is the physical basis of the correction model of this invention.

[0039] Baseline distance The calibration is completed before the system is put into measurement. The calibration method is as follows: an end calibration target surface coaxial with its photosensitive surface is set in front of the end CMOS receiving unit 200, the diameter measuring device is moved to the end calibration position and kept stationary, and the femtosecond ranging unit 400 continuously samples to obtain the distance sequence. The sampling frequency should be no less than ten times. Outlier removal is performed on the sequence using the median absolute deviation criterion, specifically: calculate the median of the sequence. and median absolute deviation If a certain sample satisfy

[0040]

[0041] These are considered outliers and removed. The arithmetic mean of the remaining valid samples is then calculated, and the result is the baseline distance. This information is written into the configuration parameters of the host computer processing unit 700. This calibration process needs to be re-executed to update the settings after any reinstallation or noticeable displacement of the transmitter or end support. This value ensures the accuracy of subsequent scaling.

[0042] The synchronization control and communication unit 500 is a key component for data pairing in the system. This unit maintains a globally unified clock and timestamps the CMOS spot data, diameter measurement data, and femtosecond ranging data based on this clock. During a measurement operation, after the surveyor places the diameter measuring device at a bearing measuring point and triggers data acquisition, the synchronization control and communication unit 500 simultaneously sends acquisition commands to the end CMOS receiving unit 200, the diameter measuring unit 300, and the femtosecond ranging unit 400, or reads their respective most recent valid data frames, recording the spot positions at the same time. Original diameter measurement value and axial distance The data is encapsulated into a set of unified timestamp data frames and uploaded to the host computer processing unit 700 via wired or wireless communication links. In actual engineering scenarios, the frame rate of the end CMOS, the sampling rate of the diameter measuring sensor, and the pulse repetition frequency of the femtosecond ranging are often not completely consistent. For this situation of asynchronous sampling frequencies, the synchronization control and communication unit 500 adopts the following processing strategy: using the diameter measuring trigger time as the reference timestamp, it searches for the two frames closest to that time in the CMOS spot data stream, performs linear interpolation on the spot center coordinates, and obtains a drift vector that is precisely aligned with the diameter measuring time. The femtosecond ranging data is also time-aligned according to the same principle. This timestamp-based linear interpolation pairing mechanism ensures the time consistency of multi-source asynchronous data in the correction calculation, avoiding additional errors introduced by acquisition delays or frequency differences.

[0043] The power supply unit 600 provides regulated power to all functional modules in the system, covering the laser emitting unit 100, the end CMOS receiving unit 200, the diameter measuring unit 300, the femtosecond ranging unit 400, the synchronization control and communication unit 500, and the host computer interface circuit. In field applications, the power supply unit 600 can use an industrial-grade regulated power supply module, in conjunction with an uninterruptible power supply (UPS) to cope with short-term power outages or voltage fluctuations, ensuring the stable operation of all sensors and communication links during long-term continuous measurements. The output of the power supply unit 600 undergoes multi-stage filtering and isolation to reduce the impact of power ripple and common-mode interference on CMOS imaging quality and femtosecond ranging accuracy.

[0044] The host computer processing unit 700 is the central hub for correction calculation and human-computer interaction. This unit receives unified timestamp data frames uploaded by the synchronization control and communication unit 500, and sequentially completes end-point drift calculation, proportional mapping, directional projection compensation, and final correction output according to the correction model of this invention. It also displays the diameter measurement values ​​and deviation trends before and after compensation on the operation interface in real time.

[0045] See Figure 2 and Figure 3 The complete process of correction calculation is as follows: The host computer processing unit 700 reads the position of the light spot in the current data frame. Compared with the stored reference position Calculate the terminal drift vector Simultaneously read the first value obtained from femtosecond ranging. Axial distance from measuring point to transmitter and the baseline distance in the configuration parameters Calculate the proportionality coefficient

[0046]

[0047] The physical meaning of this coefficient is that the perturbation of the reference laser line is approximately linearly distributed along the propagation direction, with zero drift at the transmitting end and a drift of [missing value] at the receiving end. Therefore, the disturbance experienced by the measuring point located in the middle of the axis should be scaled proportionally to its distance from the transmitter relative to the total distance. Thus, the... The laser drift at the measuring point is estimated as follows:

[0048]

[0049] in This represents the time corresponding to the timestamp pairing of the measurement point data. The drift estimate is a two-dimensional vector containing both horizontal and vertical components, which can fully reflect the actual offset state of the laser at the measurement point.

[0050] After obtaining the drift estimates for each measuring point, they need to be projected onto the diameter measurement direction to obtain an effective compensation for the original diameter measurement value. Let the first... The unit vector of the diameter measurement direction of the measuring point is

[0051]

[0052] Among the angles The measurement point number uniquely identifies the object being measured. In this embodiment, the object being measured is a semi-circular bearing bush, with three standard measurement points set on its lower half, located at the lower left, directly below, and lower right respectively. The horizontal right-hand direction on the equipment's cross-section is taken as... Establish an angle reference and measure the angle counterclockwise. The angle constants corresponding to the three measuring points are as follows: , and After the surveyor selects the current measurement point number in the host computer interface, the system automatically retrieves the corresponding angle parameters. Subsequent calculations can be performed without requiring manual input of angle values. For applications with non-standard measuring point layouts or full-circle bearings, operators can configure the angle parameters of each measuring point in the host computer, and the system will update accordingly. The logical structure of the correction model does not need to be changed when performing compensation calculations.

[0053] The compensation amount along the diametrical direction is obtained through the dot product of the drift vector and the direction vector:

[0054]

[0055] Expanding this inner product operation is...

[0056]

[0057] The sign of this compensation indicates whether laser drift causes the original diameter measurement value to be too large or too small in that diameter measurement direction. Subtracting this compensation from the original diameter measurement value yields the corrected diameter measurement value.

[0058]

[0059] This is the actual diameter measurement result after drift compensation.

[0060] like Figure 3 As shown, the above correction calculation process can be summarized into four sequential steps: Step A is the end-point drift calculation, obtaining... Step B is a scaling process, which is... and Obtain drift estimates for each measuring point Step C is directional projection, which projects the two-dimensional drift vector onto the calibrating direction to obtain the scalar compensation amount. Step D is the correction output, which is the final result obtained by subtracting the compensation amount from the original diameter measurement value. Meanwhile, global timing processing is integrated throughout the entire computation process, ensuring consistency through unified timestamp pairing and linear interpolation compensation. and Synchronization.

[0061] Under conditions of frequent vibration or significant ambient temperature drift, short-duration pulse interference or outliers may appear in the end-point spot drift data and the original diameter measurement data. To improve the robustness of the correction results, this embodiment... and Apply window length The system employs a sliding median filter. The sliding median filter takes two samples before and after the current sampling point to form a window of length five, and outputs the median of all samples within this window as the filtering result for the current time step. Compared to mean filtering, median filtering has a natural ability to suppress single-impulse interference and can effectively suppress sharp noise without obscuring trend changes. After sliding median filtering, the system further introduces the Hampel criterion to detect and remove residual outliers. Specifically, for a given sample in the filtered sequence... Take a window of length five centered on it, and calculate the median of the samples within that window. Absolute deviation from the median If the sample satisfies

[0062]

[0063] If an outlier is identified, it is considered an outlier. The coefficient 1.4826 is the conversion constant between the absolute deviation of the median and the standard deviation under the normal distribution assumption, making the criterion threshold equivalent to the three-standard-deviation criterion. Samples identified as outliers are replaced with the median of their respective windows before entering the subsequent correction calculation process. This dual preprocessing strategy of "sliding median filtering + Hampel outlier replacement" effectively suppresses the impact of sudden interference on the final compensation accuracy while maintaining real-time data tracking characteristics, making it suitable for engineering stability requirements in field measurement environments.

[0064] During the measurement process, the operator moves the diameter measuring device along the axis to the measurement position of each bearing section one by one. After reaching each measuring point, the operator selects the corresponding measuring point number on the host computer interface and triggers the acquisition. The system immediately completes the encapsulation and uploading of a set of data frames. The host computer completes all the above correction calculations within hundreds of milliseconds and simultaneously displays the original diameter measurement value of that measuring point on the screen. Compensation amount and the diameter measurement after correction This allows operators to easily monitor measurement status and deviation trends in real time. Once all bearing sections have been measured, the host computer processing unit 700 calculates the center deviation vector based on the corrected diameter values ​​of each section, and outputs the center deviation values ​​for each section along with recommended adjustment amounts, providing a quantitative basis for installation personnel's bearing adjustment operations. All measurement data and correction process parameters are automatically stored in the host computer's database for subsequent traceability and quality auditing.

[0065] In an alternative implementation scenario, when the object being measured is a full-circular bearing rather than a semi-circular bearing, the measuring points can be set at four or more locations evenly distributed along the circumference, with each measuring point corresponding to an angle parameter. Determined by dividing the circumference into equal parts, for example, taking the following for a four-point layout: , , and When using a six-point layout, it is based on The points are arranged sequentially at intervals. The mathematical structure of the correction model remains completely unchanged; only the contents of the angle parameter table need to be adjusted according to the layout of the measuring points to adapt to different centering measurement requirements.

[0066] In another modified embodiment, when the shaft system span is particularly large or the number of intermediate bearing segments is large, one or more intermediate CMOS spot detection nodes can be added at the middle position of the shaft system to detect the drift amount of the laser at the endpoints of each segment. In this case, the proportional mapping within each segment is still performed according to the linear scaling principle of the present invention, but the reference distance and end drift vector of each segment are independently calibrated and calculated, thereby shortening the effective length of the linear approximation to the range of each sub-segment, further improving the engineering applicability of the correction accuracy under ultra-long shaft system conditions.

[0067] The above implementation fully embodies the core concept of this invention: real-time information on laser reference line disturbance is obtained through end-of-line CMOS spot offset detection; femtosecond ranging is used to obtain the precise position of each measuring point on the axis and establish a proportional mapping relationship with end-of-line drift; then, the two-dimensional drift vector is projected onto the specific diameter measurement direction to obtain a scalar compensation amount; finally, real-time correction of the diameter measurement value of each measuring point is achieved under the guarantee of a unified timestamp pairing mechanism. This complete closed loop does not rely on a priori models of environmental disturbances, nor does it require the laser reference line to remain absolutely stable throughout the entire measurement cycle. Instead, it eliminates the influence of disturbances from the measurement results through online detection and real-time compensation, acknowledging their objective existence. This achieves high-precision and traceable engineering inspection requirements in the centerline alignment measurement of large shaft systems and multi-shaft bearing sections in the power, energy, shipbuilding, and metallurgical industries.

[0068] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A real-time laser perturbation correction method, applied to a system including a laser emitting unit, an end-sensor CMOS receiving unit, a diameter measuring unit, a femtosecond ranging unit, and a host computer processing unit, characterized in that, Includes the following steps: Step A: Establish a laser reference line between the transmitting end and the end end of the shaft system, and acquire the laser at any time using the end CMOS receiving unit. End spot position and initial reference position The terminal drift vector is calculated. ; Step B, obtain the diameter measuring device moved to the first... When measuring points, the original diameter value measured by the diameter measuring unit. and the femtosecond ranging unit measured the first Real-time axial distance from the measuring point to the transmitting end ; Step C, pair the end drift vectors based on the same timestamp. With real-time axial distance Calculate the proportionality coefficient ,in The calibration reference distance between the transmitter and the receiver is used, and the first step is calculated based on the aforementioned scaling factor. Laser drift estimation vector at the measurement point Step D, obtain the first Unit vector of the measuring point's diameter direction The laser drift estimation vector Projecting onto the diameter measurement direction yields the compensation amount along that direction. ; Step E, the original diameter measurement value Subtract the compensation amount The drift-compensated deviation measurement value is obtained. .

2. The method according to claim 1, characterized in that, The pairing process based on the same timestamp in step C specifically includes: using the diameter measurement trigger time as the reference timestamp, searching for the two frames of data closest to that time in the spot data stream output by the end CMOS receiving unit, performing linear interpolation on the spot center coordinates, and obtaining the end drift vector precisely aligned with the diameter measurement time. .

3. The method according to claim 1, characterized in that, The calibration method for the reference distance includes: setting an end calibration target surface coaxial with its photosensitive surface in front of the end CMOS receiving unit; moving the diameter measuring device to the end calibration position and keeping it stationary, and continuously sampling to obtain a distance sequence through the femtosecond ranging unit; using the median absolute deviation criterion to remove outliers from the distance sequence; calculating the arithmetic mean of the remaining valid samples after removing outliers, and using the result as the reference distance in the configuration parameters. .

4. The method according to claim 1, characterized in that, The unit vector of the diameter measurement direction in step D The expression is ,in The angle parameter is uniquely determined by the measuring point number; the calculation formula for the compensation amount is expanded as follows: ,in and These are the terminal drift vectors. In the horizontal and vertical components.

5. The method according to claim 1, characterized in that, After acquiring the data in steps A and B, the terminal drift vector sequence and the original diameter measurement value sequence required for calculation are subjected to dual preprocessing. The preprocessing process includes: firstly, applying a sliding median filter to the data sequence; then, introducing the Hampel criterion to detect residual outliers in the filtered sequence, and replacing the samples identified as outliers with the median of their respective windows.

6. A real-time laser perturbation correction system, used to implement the method described in any one of claims 1 to 5, characterized in that, include: The laser emitting unit, located at one end of the axis, is used to emit a reference laser line that propagates along the axis. The end CMOS receiving unit is installed at the other end of the axis system. It is used to receive the reference spot formed by the reference laser line, continuously acquire spot images at a set frame rate and extract the center coordinates, and output the end drift vector. The diameter measurement unit is used to obtain the original diameter measurement value from the inner surface of the bearing bush at the measurement point to the laser reference line; The femtosecond ranging unit uses an independent femtosecond laser optical path to measure the real-time axial distance from the measuring point where the diameter measuring unit is located to the transmitting end; The synchronization control and communication unit maintains a globally unified clock, which is used to timestamp the data from the end CMOS receiving unit, the diameter measuring unit, and the femtosecond ranging unit, and encapsulate them into unified timestamp data frames. The host computer processing unit is connected to the synchronous control and communication unit. It receives the data frame, calculates the laser drift estimation vector at the measuring point based on the ratio mapping relationship between the real-time axial distance and the calibration reference distance, projects the laser drift estimation vector onto the diameter measurement direction to obtain the compensation amount, and outputs the diameter measurement value after compensation and correction.

7. The system according to claim 6, characterized in that, The femtosecond ranging unit and the diameter measuring unit are integrated on the same portable diameter measuring device. At least three femtosecond reflection target points are arranged at non-collinear positions on the diameter measuring device body. The femtosecond ranging unit performs multi-target calculation on the flight time or phase difference of each target point and simultaneously outputs the position information of the diameter measuring device along the axial direction, as well as the tilt and rotation attitude information.

8. The system according to claim 6, characterized in that, The laser emitting unit uses a laser in the invisible light band. Its output beam is split by a semi-transparent mirror arranged at the center of the device and then propagates along the axis to the end CMOS receiving unit through transmission or reflection. The operating wavelength of the laser is matched with the peak response band of the imaging chip of the end CMOS receiving unit.

9. The system according to claim 6, characterized in that, When the shaft system under test contains multiple intermediate bearing segments, one or more intermediate CMOS spot detection nodes are added at the middle position of the shaft system. Each segment corresponds to a calibration reference distance, and proportional mapping and error compensation calculations are performed independently in each segment.

10. The system according to claim 6, characterized in that, It also includes a power supply unit, which uses an industrial-grade voltage regulator module in conjunction with an uninterruptible power supply device, and the output end is equipped with multi-stage filtering and isolation circuits to provide regulated power supply for the laser emitting unit, the end CMOS receiving unit, the diameter measuring unit, the femtosecond ranging unit, the synchronization control and communication unit, and the host computer interface circuit.

Images