Method and system for measuring coaxiality of a hole system based on a laser beam

Abstract

This invention relates to the field of hole coaxiality measurement technology, specifically to a method and system for measuring the coaxiality of machined holes based on a laser beam. It includes identifying defect points and associated defect points during the re-inspection process, and then re-locating the defect points based on a defect-association mapping set. A precise re-inspection adjustment path is constructed based on the secondary location distribution of the defect points, and a fixed-point re-inspection is performed according to this path. This solution obtains the positional relationship between defect points and associated defect points, constructs a defect-association mapping set, and re-locates the defect points based on the re-inspection process, the associated defect points, and the defect-association mapping set. A precise re-inspection adjustment path is constructed based on the secondary location distribution of the defect points, and a fixed-point re-inspection is performed according to this path. This allows for targeted measurement path planning for the coaxiality testing equipment and location detection of each defect point after re-inspection, improving the efficiency of the re-inspection process.

Description

Technical Field

[0001] This invention relates to the field of hole coaxiality measurement technology, and more specifically, to a method and system for measuring the coaxiality of machined holes based on a laser beam. Background Technology

[0002] In the field of mechanical manufacturing, the coaxiality of multiple bearing holes or shaft holes (i.e., hole systems) is a key geometric tolerance that determines the assembly accuracy, operational stability, and service life of the entire machine. Excessive coaxiality will directly lead to drive shaft deflection, uneven bearing wear, increased vibration and noise, and even mechanism jamming.

[0003] Currently, non-contact measurement methods based on laser beams are widely used for the precision measurement of the coaxiality of machined hole systems. This method typically utilizes the excellent directionality and high brightness of laser light to establish an optical reference axis traversing the measured hole system. A probe integrating a laser displacement sensor is inserted into the hole, and a precision rotating spindle drives the probe to perform a 360° rotation scan. The probe emits a laser beam to the hole wall in real time and receives diffuse reflection spots. The distance values ​​from the sensor to various points on the hole wall are obtained based on the triangulation principle. The center of each cross-sectional profile is fitted using the least squares method, and then the centers of each cross-section are connected and their variation relative to the evaluation datum is calculated to achieve coaxiality evaluation.

[0004] In actual machining and inspection processes, measurement is not the ultimate goal; the closed-loop control of measurement-repair-re-inspection is the core link to ensure product qualification rate. When using the aforementioned laser measurement system for the first round of inspection, the system can not only output the coaxiality numerical results, but also accurately locate local geometric defects, such as protrusions and depressions, on the inner wall of the hole system by analyzing the radial runout data of various points on the hole wall.

[0005] After defect handling is completed, the workpiece needs to be re-clamped back onto the laser coaxiality measuring equipment for a second inspection to confirm whether the defect has been completely eliminated and whether the coaxiality still meets the tolerance requirements. At this point, the existing measurement process faces a significant technical bottleneck.

[0006] Because the workpiece has undergone a disassembly-re-clamping process, even regular cylindrical rotating workpieces (such as cylinder liners and bearing housings) will experience shifts in their circumferential angular position and axial reference on the measuring machine due to repeated positioning errors of the fixture, changes in clamping force, or chip damage. For irregularly shaped box-shaped workpieces (such as engine blocks and transmission housings), the clamping reference based on the external blank surface or process boss has low accuracy, and the changes in spatial posture after repeated clamping are more significant.

[0007] The consequence of this change in clamping position is that the coordinates of defect points recorded in the initial measurement data are completely invalid during the second inspection. If the measurement system directly uses the original coordinates for targeted scanning, the laser spot will not be able to accurately align with the repaired area, and may even result in missed detections. To reposition the repaired area, the operator has to perform a complete scan and reconstruction of the entire hole system again, manually identifying the repair effect by comparing the two complete point cloud data or polar coordinate contour maps. This process greatly increases the auxiliary time for re-inspection, severely restricts the inspection cycle on mass production lines, and reduces the overall utilization rate of the equipment.

[0008] To address the aforementioned issues, there is an urgent need for a laser beam-based method and system for measuring the coaxiality of machined holes, which allows for planning detection routes based on the location distribution of defect points. Summary of the Invention

[0009] The purpose of this invention is to provide a method and system for measuring the coaxiality of machined hole systems based on laser beams, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, one objective of this invention is to provide a method for measuring the coaxiality of machined hole systems based on a laser beam, comprising the following steps: S1. Perform center position correction on the coaxiality testing equipment and obtain the center point parameters; S2. Set the detection parameters, adjust the coaxiality detection equipment according to the detection parameters, capture defect points, extract defect parameters, and construct a defect parameter dataset. S3. Configure coaxial positioning auxiliary equipment to capture defect correlation points; S4. Based on the changes in detection parameters, obtain the positional relationship between defect points and defect-related points, and construct a defect-related mapping set; S5. Locate the re-inspection defect points and defect association points during the re-inspection process, and locate the re-inspection defect points a second time based on the defect-association mapping set; S6. Construct a precise re-inspection and adjustment path based on the distribution of re-inspection defect points from the secondary positioning, and perform fixed-point re-inspection according to the precise re-inspection and adjustment path.

[0011] As a further improvement to this technical solution, the method for center position correction of the coaxiality detection device in S1 includes the following steps: S1.1 Clamp and fix the workpiece to be tested, expose the hole to be tested, and place the coaxiality testing device at the center of the end of the rotating shaft; S1.2. Insert the rotating shaft into the center of the hole to be tested, and drive the rotating shaft to rotate 360 ​​degrees at a constant angular velocity using a motor. S1.3, Synchronously acquire angle encoder values and the test values ​​of the coaxiality testing equipment Obtain a set of polar coordinate data pairs ,in to These represent the polar coordinates of different measurement points, and m represents the total number of measurement points; S1.4. Establish a data model based on the polar coordinate data and obtain the rotation axis adjustment parameters at the current position.

[0012] As a further improvement to this technical solution, the method for establishing the data model in S1.4 includes the following steps: S1.4.1. Assume the ideal cross-section of the hole to be measured is a perfect circle with a radius of... The center of the circle is Let the center of rotation of the shaft be... The eccentricity between the two is The eccentricity direction angle is At any angle Location, distance measured by the laser probe The following geometric relations must be satisfied: ; in This could be due to noise or roundness error. S1.4.2. Sort the measured N points into a sequence. , ; S1.4.3 Directly Calculate the Coefficients of the First-Order Cosine Term Using Discrete Fourier Transform and the coefficients of the first-order sine term : ; ; S1.4.4, from the coefficients of the first-order cosine term and the coefficients of the first-order sine term Calculate the eccentricity direction angle and eccentricity ; ; ; The obtained eccentricity This is the distance the axis of rotation needs to move towards the center, and the resulting eccentricity angle. This refers to the direction in which the shaft becomes eccentric.

[0013] As a further improvement to this technical solution, the method for capturing defect points in S2 includes the following steps: S2.1 Obtain the radius of the hole to be tested and establish a standard radius error range. ,in This represents the maximum allowable error during the use of the workpiece. S2.2. A laser is emitted by a laser probe deployed in the coaxiality detection equipment. The laser light is reflected by the inner wall of the hole to be measured. The reflected light is captured by a receiver, and the distance h of the current measurement point is calculated based on the time taken to capture the reflected light. S2.3, Mark the serial number of the current measurement point. ,in T represents the number of rotations, and T represents the time taken to rotate one revolution along the same cross-section at the inner end of the hole being measured. This is the total time taken for the detection device to rotate from the initial point to the current measurement point, and , The unit interval is the detection time; S2.4 Determine the distance h for each measurement point with a given serial number; The distance of the measurement point with the current serial number If so, then mark the measurement point as a regular measurement point; The distance of the measurement point with the current serial number Then mark the measurement point as a defect point and calculate the corresponding defect difference. Among them, the defect difference > .

[0014] As a further improvement to this technical solution, the method for constructing the defect parameter dataset in S2 includes the following steps: S2.10 Extract defect parameters for each defect point; S2.11. Obtain the number of pulses P output for one revolution of the driven shaft based on the shaft rotation speed, where ,in The frequency of the pulse signal. This refers to the rotational speed of the shaft. S2.12 Calculate the mechanical angle of the defect point based on the pulse number P. ,in , This represents the total number of pulses accumulated from the starting position. S2.13 Extract the mechanical angle of the current defect point Unit interval detection time and the unit displacement length of the rotating shaft The polar coordinate position of the current defect point Obtain the polar coordinates of each defect point and construct a defect parameter dataset.

[0015] As a further improvement to this technical solution, the defect association points captured in S3 are of regular shape.

[0016] As a further improvement to this technical solution, the method for constructing the defect-association mapping set in S4 includes the following steps: S4.1 Extract the polar coordinates of each defect point. Calculate the positional difference parameter between the defect-associated point and the defect-point, where the positional difference parameter includes the number of rotations from the defect-associated point to the defect point and the offset angle. And the horizontal distance L; S4.2 Calculate the offset angle ,in ,in The number of rotations. The included angle formed between the coaxial positioning auxiliary equipment and the coaxiality detection equipment; S4.3 Calculate the horizontal distance L, where In the formula The distance between the coaxial positioning auxiliary equipment and the defect-related point at the initial position. This represents the total number of times the axis of rotation displaces the hole to be measured when the current defect point is detected. S4.4 Extract the position difference parameters between each defect point and the defect-associated point, and construct a defect-associated mapping set.

[0017] As a further improvement to this technical solution, the method for locating and re-inspecting defect points in S5 includes the following steps: S5.1 Calculate the position difference parameter between the current re-inspection defect point and the defect association point, and respond to the re-inspection defect point according to the defect-association mapping set; S5.2 Determine the positional relationship of the defects in the re-inspection; When the position difference parameter between the current re-inspection defect point and the defect association point corresponds one-to-one with a certain position difference parameter in the defect-association mapping set, the sequence number of the re-inspection defect point is extracted, and the first re-inspection defect point collected is marked as the initial defect point. When the position difference parameter between the current re-inspected defect point and the defect-associated point is different from all position difference parameters in the defect-associated mapping set, the re-inspected defect point is marked as a new defect point, and the position difference parameter between the current new defect point and the defect-associated point is extracted. S5.3, Plan the detection path; When the defect point collected for the first time is a new type of defect point, a second detection is performed according to the set detection parameters to obtain the position difference parameter between the corresponding new type of defect point and the defect-related point, and the defect-related mapping set is updated. When the defect point collected for the first time is a defect point to be re-inspected, the sequence number of the initial defect point is extracted, and the position difference parameter between the remaining unre-inspected defect points and the initial defect point is obtained according to the defect-association mapping set. Re-inspection detection parameters are generated, and a precise re-inspection adjustment path is constructed.

[0018] As a further improvement to this technical solution, the method for constructing the precise re-inspection and adjustment path in S5.3 includes the following steps: S5.3.1 Adjust the rotating shaft according to the re-inspection parameters and regulate the coaxiality detection equipment to capture defects that have not been re-inspected; S5.3.2 Obtain the distance h of the corresponding unre-inspected defect points and make a judgment; When the distance h of the uninspected defect points If so, the defect point that was not re-inspected is marked as a regular measurement point; When the distance of the uninspected defect points If the defect point that was not re-inspected is marked as a re-inspected defect point, the defect difference value corresponding to each re-inspected defect point is calculated. Update the defect parameter dataset after re-inspection, and carry out a new round of defect repair according to the updated defect parameter dataset; S5.3.3 Repeat the re-inspection process until no re-inspection defects appear. Perform the repair inspection work according to the inspection parameters until no new defects appear.

[0019] The second objective of this invention is to provide a system for measuring the coaxiality of machined hole systems based on a laser beam, comprising a device end, a communication end, a processing end, and a control end; The device is used to control the measuring equipment, correct the center position of the coaxiality detection equipment, and capture defect points and defect-related points. The communication terminal establishes an information transmission channel between the device and the processing terminal by building a network channel, uploading the detection parameters obtained by the device to the processing terminal, and transmitting the control parameters to the device to control each measuring device to perform targeted measurements; The processing end is used to construct a defect parameter dataset and a defect-association mapping set, calculate the position difference parameter between the defect point and the defect-associated point, and feed the position difference parameter back to the control end. The control terminal uses position difference parameters and defect-association mapping sets to locate and classify re-inspection defect points and new defect points during the re-inspection process. Based on the location distribution of re-inspection defect points obtained from secondary positioning, it constructs a precise re-inspection adjustment path and sends it to the equipment terminal to control the corresponding equipment to perform fixed-point re-inspection according to the precise re-inspection adjustment path.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: In this laser beam-based method and system for measuring the coaxiality of machined holes, the positional relationship between defect points and defect-related points is obtained to construct a defect-related mapping set. Based on the re-inspection defect points, defect-related points, and defect-related mapping set during the re-inspection process, the re-inspection defect points are located twice. A precise re-inspection adjustment path is constructed according to the positional distribution of the re-inspection defect points located twice. Fixed-point re-inspection is performed according to the precise re-inspection adjustment path. Targeted measurement path planning is carried out for the coaxiality detection equipment. After re-inspection, each defect point is located and detected, thereby improving the efficiency of re-inspection. Attached Figure Description

[0021] Figure 1 This is a diagram illustrating the overall method steps of the present invention; Figure 2 This is a schematic diagram of the overall system of the present invention. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1 As shown, one of the objectives of this invention is to provide a method for measuring the coaxiality of machined hole systems based on a laser beam, comprising the following steps: S1. Perform center position correction on the coaxiality testing equipment and obtain the center point parameters; S2. Set the detection parameters, adjust the coaxiality detection equipment according to the detection parameters, capture defect points, extract defect parameters, and construct a defect parameter dataset. S3. Configure coaxial positioning auxiliary equipment to capture defect correlation points; S4. Based on the changes in detection parameters, obtain the positional relationship between defect points and defect-related points, and construct a defect-related mapping set; S5. Locate the re-inspection defect points and defect association points during the re-inspection process, and locate the re-inspection defect points a second time based on the defect-association mapping set; S6. Construct a precise re-inspection and adjustment path based on the distribution of re-inspection defect points from the secondary positioning, and perform fixed-point re-inspection according to the precise re-inspection and adjustment path.

[0024] The specific plan is as follows: In the specific measurement process, firstly, in order to eliminate the influence of irrelevant factors on the measurement process, namely the positional offset of the measuring equipment which will cause errors in the measurement results, it is necessary to perform center position calibration on the coaxiality testing equipment before measurement. The specific method is as follows: The workpiece is clamped and fixed to expose the hole to be measured. The coaxiality testing device is placed at the center of the end of the rotating shaft, and the shaft is extended into the hole near the center. In this state, the shaft is not necessarily at the exact center of the hole. The shaft is driven by a motor to rotate 360 ​​degrees at a constant angular velocity, that is, to rotate the shaft one revolution along the inner end of the hole. During the rotation, the angle encoder values ​​are collected simultaneously. (i.e., the angular difference between two measuring points) and the values ​​measured by the coaxiality testing equipment. (Configure a laser probe, emit laser light that reflects off the inner wall of the hole to be measured, and capture the reflected light with a configured receiver to obtain the distance between the laser probe and the measurement point), and obtain a set of polar coordinate data pairs. ,in to The polar coordinates of different measurement points are represented by , and m represents the total number of measurement points. A data model is established based on the polar coordinate data: Assume the ideal cross-section of the hole to be measured is a perfect circle with radius . The center of the circle is Let the center of rotation of the shaft be... The eccentricity between the two is The eccentricity direction angle is At any angle Location, distance measured by the laser probe The following geometric relations must be satisfied: ; in This could be due to noise or roundness error. The eccentricity direction angle is calculated using a frequency domain extraction algorithm based on Fourier series. and eccentricity ; First, sort the N measured points into a sequence. , ; Since the eccentricity error manifests as a fundamental frequency (1st order) sine wave in the signal, the coefficients of the first-order cosine term can be directly calculated using the discrete Fourier transform. and the coefficients of the first-order sine term : ; ; The coefficients of the first-order cosine term and the coefficients of the first-order sine term Calculate the eccentricity direction angle and eccentricity ; ; ; The obtained eccentricity This is the distance the axis of rotation needs to move towards the center, and the resulting eccentricity angle. This refers to the direction in which the shaft becomes eccentric.

[0025] Based on the eccentricity direction angle and eccentricity The calculated values ​​are used to adjust the position of the rotating shaft so that the coaxiality testing device is positioned at the center of the hole to be tested.

[0026] After completing the position calibration of the coaxiality testing equipment, the testing process begins. To ensure the accuracy of the testing, the testing parameters need to be set in advance, including the shaft rotation speed, unit interval testing time, and unit displacement length of the shaft. The coaxiality testing equipment is then adjusted according to the testing parameters to capture defect points, extract defect parameters, and construct a defect parameter dataset. During the defect point extraction process, the radius of the hole to be tested, i.e., the radius of the ideal perfect circle, is obtained. Construct a standard radius error range ,in To determine the maximum allowable error during workpiece use, a laser probe deployed in the coaxiality detection equipment emits a laser beam. The laser beam is reflected off the inner wall of the hole to be measured. A receiver captures the reflected light, and the distance h of the current measurement point is calculated based on the time taken to capture the reflected light. The corresponding algorithm formula is as follows: ; in The speed at which laser light travels through air is typically taken as 3 × 10⁻⁶. m / s, t is the time taken for the laser to travel from the laser probe, through reflection at the measurement point, and then be received by the receiver, marking the sequence number of the current measurement point. ,in The value represents the number of rotations. Because the hole to be measured has a certain depth, the distance the rotating shaft extends into the hole needs to be constantly adjusted during the testing process to measure different areas of the hole. T represents the time taken to rotate one revolution along the same cross-section at the inner end of the hole. This is the total time taken for the detection device to rotate from the initial point to the current measurement point, and , The unit interval detection time means that a laser is emitted once at the corresponding measurement point every unit interval detection time. m takes a positive integer, and the distance h is determined for each sequence number measurement point. The distance of the measurement point with the current serial number If so, then mark the measurement point as a regular measurement point; The distance of the measurement point with the current serial number Then mark the measurement point as a defect point and calculate the corresponding defect difference. Among them, the defect difference > .

[0027] After locating the defect points, defect parameters are extracted for each defect point, specifically by obtaining the mechanical angle of the current defect point using the shaft rotation speed. That is, the angle formed between the current defect point and the initial point in the current revolution, and the number of pulses P output for driving the shaft to rotate one revolution is obtained according to the shaft rotation speed. ,in The frequency of the pulse signal. Given the shaft rotation speed, calculate the mechanical angle of the defect point based on the pulse number P. ,in , Extract the mechanical angle of the current defect point based on the total number of pulses accumulated from the starting position. Unit interval detection time and the unit displacement length of the rotating shaft The polar coordinate position of the current defect point Obtain the polar coordinates of each defect point and construct a defect parameter dataset.

[0028] Furthermore, since there are multiple reference points on the workpiece where the hole to be measured is located, and the relative position between these reference points and each defect point does not change with the fixed position of the workpiece, this solution uses a coaxial positioning auxiliary device during the initial defect point detection process. This device, consisting of an external laser probe mounted on the side of a rotating shaft and rotating coaxially with the shaft, captures reference points on the surface of the workpiece where the hole to be measured is located and marks them as defect-related points. These defect-related points are regular in shape, such as the surface of a circular bolt or a non-penetrating spherical hole, and are selected by the measurement personnel. At the initial measurement point, the coaxial positioning auxiliary device (external laser probe) is rotated and moved up and down to ensure that the external laser probe can capture the defect-related points, i.e., the laser can be emitted to the center position of the defect-related points. The adjustment parameters of the current coaxial positioning auxiliary device, including the rotation angle and displacement distance, are obtained, while the coaxiality detection device remains in a fixed position.

[0029] During the defect point capture process, the polar coordinate positions of each defect point are extracted. Calculate the positional difference parameter between the defect-associated point and the defect-point, where the positional difference parameter includes the number of rotations from the defect-associated point to the defect point and the offset angle. and the horizontal distance L, where ,in The number of rotations. This refers to the angle formed between the coaxial positioning auxiliary equipment and the coaxiality detection equipment, i.e., the rotation angle. In the formula The distance between the coaxial positioning auxiliary equipment and the defect-related point at the initial position. To detect the total number of times the shaft rotates to the hole to be measured when the current defect point is detected, the position difference parameters between each defect point and the defect-associated point are extracted, and a defect-association mapping set is constructed, that is, defect points with different numbers and defect-associated points form specific position difference parameters.

[0030] Furthermore, during the re-inspection process, regardless of how the workpiece is clamped and fixed, the position difference parameter between the corresponding defect point and the defect-related point will not change. Therefore, it is necessary to locate the re-inspection defect point and the defect-related point during the re-inspection process, calculate the position difference parameter between the current re-inspection defect point and the defect-related point, and respond to the re-inspection defect point according to the defect-related mapping set. When the positional difference parameter between the currently inspected defect point and the defect-associated point corresponds one-to-one with a certain positional difference parameter in the defect-association mapping set, i.e., the number of rotations from the defect-associated point to the defect point and the offset angle... If the data of the three factors—the horizontal distance L, the re-inspection defect point, and the horizontal distance L—are all kept consistent, then the re-inspection defect point is marked as a re-inspection defect point (that is, it indicates that the current re-inspection defect point is still in a defective state after repair). The serial number of the re-inspection defect point is extracted, and the first re-inspection defect point collected is marked as the initial defect point. When the position difference parameter between the current re-inspected defect point and the defect-associated point is different from all position difference parameters in the defect-associated mapping set, the re-inspected defect point is marked as a new defect point, and the position difference parameter between the current new defect point and the defect-associated point is extracted. When the defect point collected for the first time is a new type of defect point, a second detection is performed according to the set detection parameters to obtain the position difference parameter between the corresponding new type of defect point and the defect-related point, and the defect-related mapping set is updated. When the defect point collected initially is a re-inspection defect point, the sequence number of the initial defect point is extracted. Based on the defect-association mapping set, the position difference parameter between the remaining unre-inspected defect points and the initial defect point is obtained. Re-inspection detection parameters are generated, and a precise re-inspection adjustment path is constructed. The specific scheme is as follows: Adjust the rotating shaft according to the re-inspection parameters, regulate the coaxiality detection equipment to capture defects that have not been re-inspected, obtain the distance h of the corresponding defects that have not been re-inspected, and make a judgment. When the distance h of the uninspected defect points If so, the defect point that was not re-inspected is marked as a regular measurement point; When the distance of the uninspected defect points If the defect point that was not re-inspected is marked as a re-inspected defect point, the defect difference value corresponding to each re-inspected defect point is calculated. The defect parameter dataset after re-inspection is updated, and a new round of defect repair is carried out according to the updated defect parameter dataset. In the repeated re-inspection process, until no re-inspection defect points appear, the repaired inspection work is carried out according to the detection parameters until no new defect points appear, and the coaxiality measurement of the entire hole system is completed.

[0031] In practical application, this solution constructs a defect-association mapping set by obtaining the positional relationship between defect points and defect-related points. Based on the re-inspection defect points, defect-related points, and defect-association mapping set during the re-inspection process, the re-inspection defect points are located a second time. A precise re-inspection adjustment path is constructed according to the positional distribution of the re-inspection defect points located a second time. Fixed-point re-inspection is carried out according to the precise re-inspection adjustment path. Targeted measurement path planning is performed for the coaxiality detection equipment. After re-inspection, each defect point is located and detected, thereby improving the efficiency of re-inspection.

[0032] Please see Figure 2 As shown, a second objective of this invention is to provide a system for measuring the coaxiality of machined hole systems based on a laser beam, comprising a device end, a communication end, a processing end, and a control end; The equipment end is used to control the measuring equipment, namely the servo motor that drives the rotating shaft, the rotating shaft, and the laser probe (main / sub-probe, the main probe is used to capture defect points, and the sub-probe is used to capture defect-related points), to perform center position correction on the coaxiality detection equipment, and to capture defect points and defect-related points; The communication end establishes a network channel to create an information transmission channel between the device end and the processing end. It uploads the detection parameters obtained by the device end to the processing end and transmits the control parameters to the device end, thereby controlling each measuring device to perform targeted measurements. The processing end is used to construct a defect parameter dataset and a defect-association mapping set, calculate the position difference parameter between defect points and defect-associated points, and feed the position difference parameter back to the control end. The control terminal uses position difference parameters and defect-association mapping sets to locate and classify re-inspection defect points and new defect points during the re-inspection process. Based on the location distribution of re-inspection defect points from secondary positioning, a precise re-inspection adjustment path is constructed and sent to the equipment terminal to control the corresponding equipment to perform fixed-point re-inspection according to the precise re-inspection adjustment path.

[0033] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring the coaxiality of machined hole systems based on laser beams, characterized in that: Includes the following steps: S1. Perform center position correction on the coaxiality testing equipment and obtain the center point parameters; S2. Set the detection parameters, adjust the coaxiality detection equipment according to the detection parameters, capture defect points, extract defect parameters, and construct a defect parameter dataset. S3. Configure coaxial positioning auxiliary equipment to capture defect correlation points; S4. Based on the changes in detection parameters, obtain the positional relationship between defect points and defect-related points, and construct a defect-related mapping set; S5. Locate the re-inspection defect points and defect association points during the re-inspection process, and locate the re-inspection defect points a second time based on the defect-association mapping set; S6. Construct a precise re-inspection and adjustment path based on the distribution of re-inspection defect points from the secondary positioning, and perform fixed-point re-inspection according to the precise re-inspection and adjustment path.

2. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 1, characterized in that: The method for center position correction of the coaxiality detection device in S1 includes the following steps: S1.1 Clamp and fix the workpiece to be tested, expose the hole to be tested, and place the coaxiality testing device at the center of the end of the rotating shaft; S1.

2. Insert the rotating shaft into the center of the hole to be tested, and drive the rotating shaft to rotate 360 ​​degrees at a constant angular velocity using a motor. S1.3, Synchronously acquire angle encoder values and the test values ​​of the coaxiality testing equipment Obtain a set of polar coordinate data pairs ,in to These represent the polar coordinates of different measurement points, and m represents the total number of measurement points; S1.

4. Establish a data model based on the polar coordinate data and obtain the rotation axis adjustment parameters at the current position.

3. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 2, characterized in that: The method for establishing the data model in S1.4 includes the following steps: S1.4.

1. Assume the ideal cross-section of the hole to be measured is a perfect circle with a radius of... The center of the circle is Let the center of rotation of the shaft be... The eccentricity between the two is The eccentricity direction angle is At any angle Location, distance measured by the laser probe The following geometric relations must be satisfied: ； in This could be due to noise or roundness error. S1.4.

2. Sort the measured N points into a sequence. , ; S1.4.3 Directly Calculate the Coefficients of the First-Order Cosine Term Using Discrete Fourier Transform and the coefficients of the first-order sine term : ； ； S1.4.4, from the coefficients of the first-order cosine term and the coefficients of the first-order sine term Calculate the eccentricity direction angle and eccentricity ; ； ； The obtained eccentricity This is the distance the axis of rotation needs to move towards the center, and the resulting eccentricity angle. This refers to the direction in which the shaft becomes eccentric.

4. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 1, characterized in that: The method for capturing defect points in S2 includes the following steps: S2.1 Obtain the radius of the hole to be tested and establish a standard radius error range. ,in This represents the maximum allowable error during the use of the workpiece. S2.

2. A laser is emitted by a laser probe deployed in the coaxiality detection equipment. The laser light is reflected by the inner wall of the hole to be measured. The reflected light is captured by a receiver, and the distance h of the current measurement point is calculated based on the time taken to capture the reflected light. S2.3, Mark the serial number of the current measurement point. ,in T represents the number of rotations, and T represents the time taken to rotate one revolution along the same cross-section at the inner end of the hole being measured. This is the total time taken for the detection device to rotate from the initial point to the current measurement point, and , The unit interval is the detection time; S2.4 Determine the distance h for each measurement point with a given serial number; The distance of the measurement point with the current serial number If so, then mark the measurement point as a regular measurement point; The distance of the measurement point with the current serial number If so, mark the measurement point as a defect point and calculate the corresponding defect difference. Among them, the defect difference > .

5. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 1, characterized in that: The method for constructing the defect parameter dataset in S2 includes the following steps: S2.10 Extract defect parameters for each defect point; S2.

11. Obtain the number of pulses P output for one revolution of the driven shaft based on the shaft rotation speed, where ,in The frequency of the pulse signal. This refers to the rotational speed of the shaft. S2.12 Calculate the mechanical angle of the defect point based on the pulse number P. ,in , This represents the total number of pulses accumulated from the starting position. S2.13 Extract the mechanical angle of the current defect point Unit interval detection time and the unit displacement length of the rotating shaft The polar coordinate position of the current defect point Obtain the polar coordinates of each defect point and construct a defect parameter dataset.

6. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 1, characterized in that: The defect association points captured in S3 are of regular shape.

7. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 1, characterized in that: The method for constructing the defect-association mapping set in S4 includes the following steps: S4.1 Extract the polar coordinates of each defect point. Calculate the positional difference parameter between the defect-associated point and the defect-point, where the positional difference parameter includes the number of rotations from the defect-associated point to the defect point and the offset angle. And the horizontal distance L; S4.2 Calculate the offset angle ,in ,in The number of rotations. The included angle formed between the coaxial positioning auxiliary equipment and the coaxiality detection equipment; S4.3 Calculate the horizontal distance L, where In the formula The distance between the coaxial positioning auxiliary equipment and the defect-related point at the initial position. This represents the total number of times the axis of rotation displaces the hole to be measured when the current defect point is detected. S4.4 Extract the position difference parameters between each defect point and the defect-associated point, and construct a defect-associated mapping set.

8. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 1, characterized in that: The method for locating and re-inspecting defect points in S5 includes the following steps: S5.1 Calculate the position difference parameter between the current re-inspection defect point and the defect association point, and respond to the re-inspection defect point according to the defect-association mapping set; S5.2 Determine the positional relationship of the defects in the re-inspection; When the position difference parameter between the current re-inspection defect point and the defect association point corresponds one-to-one with a certain position difference parameter in the defect-association mapping set, the serial number of the re-inspection defect point is extracted, and the first re-inspection defect point collected is marked as the initial defect point. When the position difference parameter between the current re-inspected defect point and the defect-associated point is different from all position difference parameters in the defect-associated mapping set, the re-inspected defect point is marked as a new defect point, and the position difference parameter between the current new defect point and the defect-associated point is extracted. S5.3, Plan the detection path; When the defect point collected for the first time is a new type of defect point, a second detection is performed according to the set detection parameters to obtain the position difference parameter between the corresponding new type of defect point and the defect-related point, and the defect-related mapping set is updated. When the defect point collected for the first time is a defect point to be re-inspected, the sequence number of the initial defect point is extracted, and the position difference parameter between the remaining unre-inspected defect points and the initial defect point is obtained according to the defect-association mapping set. Re-inspection detection parameters are generated, and a precise re-inspection adjustment path is constructed.

9. The method for measuring the coaxiality of machined hole systems based on a laser beam according to claim 8, characterized in that: The method for constructing the precise re-inspection and adjustment path in S5.3 includes the following steps: S5.3.1 Adjust the rotating shaft according to the re-inspection parameters and regulate the coaxiality detection equipment to capture defects that have not been re-inspected; S5.3.2 Obtain the distance h of the corresponding unre-inspected defect points and make a judgment; When the distance h of the uninspected defect points If so, the defect point that was not re-inspected is marked as a regular measurement point; When the distance of the defect points that were not re-inspected If the defect point that was not re-inspected is marked as a re-inspected defect point, the defect difference value corresponding to each re-inspected defect point is calculated. Update the defect parameter dataset after re-inspection, and carry out a new round of defect repair according to the updated defect parameter dataset; S5.3.3 Repeat the re-inspection process until no re-inspection defects appear. Perform the repair inspection work according to the inspection parameters until no new defects appear.

10. A system for implementing the laser beam-based method for measuring the coaxiality of machined hole systems as described in claim 1, characterized in that: This includes the device end, communication end, processing end, and control end; The device is used to control the measuring equipment, correct the center position of the coaxiality detection equipment, and capture defect points and defect-related points. The communication terminal establishes an information transmission channel between the device and the processing terminal by building a network channel, uploading the detection parameters obtained by the device to the processing terminal, and transmitting the control parameters to the device to control each measuring device to perform targeted measurements; The processing end is used to construct a defect parameter dataset and a defect-association mapping set, calculate the position difference parameter between the defect point and the defect-associated point, and feed the position difference parameter back to the control end. The control terminal uses position difference parameters and defect-association mapping sets to locate and classify re-inspection defect points and new defect points during the re-inspection process. Based on the location distribution of re-inspection defect points obtained from secondary positioning, it constructs a precise re-inspection adjustment path and sends it to the equipment terminal to control the corresponding equipment to perform fixed-point re-inspection according to the precise re-inspection adjustment path.

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