A method and system for calibrating the center coordinate position of a gear measuring machine

Abstract

The present application relates to the technical fields of gear measurement and machine tool calibration, in particular to a kind of gear measurement center coordinate position calibration method and system;The method comprises: obtaining initial machine tool coordinate information and reference cylindrical surface parameters, and scanning to obtain two groups of point sets at first scanning speed and second scanning speed;Mapping, interpolation and classification are carried out according to unified angle reference;The low-speed rotation center and the high-speed rotation center are calculated by first-order harmonic fitting, the coordinate offset is obtained and threshold judgment is carried out;The offset is written into machine tool coordinate transformation matrix to execute compensation;The reference cylindrical surface is rechecked and scanned, and the compensation parameters are updated according to the rechecking residual error to form closed-loop calibration;The system is used to realize the above method.

Description

Technical Field

[0001] This invention relates to the field of gear measurement and machine tool calibration technology, specifically to a method and system for calibrating the center coordinate position of a gear measurement. Background Technology

[0002] In the precision control of gear measurement centers, coordinate position calibration is an important foundation for ensuring the accuracy of tooth surface, tooth profile and tooth direction measurement results. Especially in heavy-load rotation measurement, the consistency of the rotation center position will directly affect the stability of the measurement reference.

[0003] Currently, gear measurement centers generally support calibration based on standard parts or static references. If it is necessary to ensure the consistency between the rotation center and the machine tool coordinate system under actual measurement conditions, it is usually necessary to complete the reference calibration in a stopped or low-speed state to obtain the corresponding coordinate compensation parameters.

[0004] However, when performing coordinate calibration using the above methods, there are often differences between the calibration datum and the actual load, speed, and oil film conditions of the workpiece during measurement. This makes it difficult for the static calibration results to accurately reflect the dynamic rotation center offset at the working speed. Furthermore, the clamping errors of external standard parts, switching errors, and manual intervention processes can also introduce additional deviations, resulting in a low degree of matching between the calibration results and the actual measurement conditions. At the same time, this approach usually lacks unified alignment analysis and closed-loop verification of dual-speed scanning data, making it impossible to effectively distinguish between system noise and actual displacement deviation, resulting in insufficient reliability of dynamic compensation. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for calibrating the center coordinate position of gear measurement, addressing the following technical problems: Existing gear measurement center coordinate calibration techniques have significant shortcomings in dynamic rotational offset calibration under actual working conditions and closed-loop verification based on scan data. There is an urgent need for a method and system that can more accurately handle dual-speed data alignment and dynamic closed-loop update compensation. To solve the above technical problems, the technical solution adopted by this invention is as follows:

[0006] The initial machine tool coordinate information and reference cylindrical surface parameters of the gear to be calibrated are obtained by using a scanning probe and a measurement controller; the gear to be calibrated is scanned at the first scanning speed and the second scanning speed respectively to obtain two sets of scanning points;

[0007] The two sets of scan points are classified according to the preset angle alignment rules to form data to be processed; the low-speed rotation center and high-speed rotation center are calculated based on the data to be processed, the coordinate offset is obtained, and it is determined whether the coordinate offset meets the preset displacement threshold condition; when the preset displacement threshold condition is met, the coordinate offset is written into the machine tool coordinate transformation matrix to complete the coordinate calibration; when the preset displacement threshold condition is not met, the scanning and calculation are repeated.

[0008] The reference cylindrical surface after coordinate calibration is checked and scanned. The difference between the remeasured center coordinates and the high-speed rotation center is calculated as the remeasured residual. When the remeasured residual is less than the preset residual allowable threshold, the calibration result is output. When the remeasured residual is greater than or equal to the preset residual allowable threshold, the compensation parameters are corrected and recalibrated. The coordinate compensation parameters are updated according to the check result to form a closed-loop calibration.

[0009] In some possible implementations, the initial machine tool coordinate information includes the machine tool zero point and the C-axis encoder zero position, the reference cylindrical surface parameters include the geometric parameters of the reference cylindrical surface, and also include the current measurement task number.

[0010] In some possible implementations, the angle reference classification includes using the zero position of the rotary shaft angle encoder as the angle reference, performing angle domain mapping according to a preset sampling interval, interpolating and filling in missing angle points, and aligning and classifying the two sets of scan points after mapping and filling according to the same angle reference.

[0011] In some possible implementations, the coordinate offset includes at least one of a horizontal offset, a vertical offset, and an offset magnitude.

[0012] In some possible implementations, the preset displacement threshold condition includes the offset modulus value corresponding to the coordinate offset being greater than or equal to the preset minimum displacement threshold and less than or equal to the preset maximum safe displacement limit.

[0013] In some possible implementations, the coordinate calibration includes writing the coordinate offset into the machine tool coordinate transformation matrix to correct the translation parameters corresponding to the rotation center, and then calling the corrected compensation parameters in subsequent gear measurement tasks.

[0014] In some possible implementations, the verification includes performing a verification scan on the same reference cylindrical surface again, resolving the coordinates of the remeasured center, and calculating the residual modulus as the remeasured residual based on the remeasured center coordinates and the high-speed rotation center.

[0015] In some possible implementations, when the retest residual does not meet the verification pass conditions, an abnormal status is sent back to the measurement controller, and the compensation parameters are rewritten when the scan is re-executed; when the number of consecutive recalibration failures reaches a preset threshold, a shutdown alarm is triggered.

[0016] In some possible implementations, the system includes a data acquisition module, a data classification module, a deviation judgment module, a calibration execution module, a result verification module, and a feedback module, which are respectively used to acquire and organize scan data, classify angle references, calculate the rotation center and judge displacement conditions, perform coordinate calibration, perform verification scans and calculate re-measurement residuals, and update coordinate compensation parameters based on verification results.

[0017] In some possible implementations, the data acquisition module includes a collection submodule and a recording submodule; the data classification module includes an angle alignment submodule and an interpolation completion submodule; the deviation judgment module includes a center calculation submodule and an offset judgment submodule; the calibration execution module includes a matrix correction submodule and a re-acquisition submodule; the result verification module includes a verification scan submodule and a residual comparison submodule; and the feedback module includes a status feedback submodule, a parameter rewriting submodule, and an anomaly handling submodule.

[0018] The beneficial technical effects of this invention are as follows:

[0019] 1. This invention achieves dynamic rotation center offset compensation at the actual working speed by scanning the same gear to be calibrated at two different scanning speeds and calculating the coordinate offset between the high and low speed rotation centers and writing it into the machine tool coordinate transformation matrix. This avoids the clamping errors and state differences introduced by static calibration and improves the accuracy of coordinate position calibration.

[0020] 2. This invention classifies the scan point set according to angle alignment rules, judges based on preset displacement threshold conditions, and performs a verification scan on the calibrated reference cylindrical surface to calculate the retest residual. When the residual exceeds the limit, the parameters are corrected and recalibrated, forming a closed-loop calibration mechanism that can distinguish between system noise and actual displacement deviation, ensuring the reliability of dynamic compensation. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] Figure 1 This is a flowchart illustrating a method for calibrating the coordinate position of a gear measurement center, as provided in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of a gear measurement center coordinate position calibration system provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] Reference Figure 1 A method for calibrating the coordinate position of a gear measurement center includes the following steps:

[0026] S1: Obtain the initial machine tool coordinate information and reference cylindrical surface parameters of the gear to be calibrated, and scan the gear to be calibrated at the first scanning speed and the second scanning speed respectively to obtain the first speed scanning point set and the second speed scanning point set;

[0027] S2: According to the preset angle alignment rules, classify the first speed scanning point set and the second speed scanning point set by angle reference to obtain the data to be processed. The data to be processed includes the aligned first speed scanning point set and the aligned second speed scanning point set.

[0028] S3: Calculate the low-speed rotation center based on the aligned first rotational speed scan point set in the data to be processed, and calculate the high-speed rotation center based on the aligned second rotational speed scan point set. Calculate the coordinate offset and determine whether the coordinate offset meets the preset displacement threshold condition.

[0029] S4: When the preset displacement threshold condition is met, the coordinate offset is written into the machine tool coordinate transformation matrix as a coordinate compensation parameter, and coordinate calibration is performed; when the preset displacement threshold condition is not met, steps S1 to S3 are re-executed.

[0030] S5: Perform a verification scan on the reference cylindrical surface after coordinate calibration, and calculate the difference between the remeasured center coordinates and the high-speed rotation center as the remeasured residual; output the calibration result when the remeasured residual is less than the preset residual allowable threshold; when the remeasured residual is greater than or equal to the residual allowable threshold, correct the coordinate compensation parameters and recalibrate.

[0031] S6: Update the coordinate compensation parameters based on the verification results.

[0032] The initial machine coordinate information in S1 includes the machine zero point and the C-axis encoder zero position; the reference cylindrical surface parameters include the geometric parameters of the reference cylindrical surface; and it also includes the current measurement task number.

[0033] The angle reference classification in S2 includes: setting an angle reference, using the zero position of the C-axis angle encoder as the angle reference, performing angle domain mapping according to a preset sampling interval, interpolating and filling in missing angle points, and aligning and classifying the mapped and filled first speed scan point set and second speed scan point set according to the same angle reference.

[0034] The coordinate offsets in S3 include the X-axis offset. Y-axis offset and offset modulus At least one of them.

[0035] The preset displacement threshold conditions in S3 include: the offset magnitude corresponding to the coordinate offset is greater than or equal to the preset minimum displacement threshold and less than or equal to the preset maximum safe displacement limit.

[0036] Coordinate calibration in S4 includes: writing coordinate offsets into the machine tool coordinate transformation matrix to correct the translation parameters corresponding to the rotation center of the C-axis, and calling the corrected compensation parameters in subsequent gear measurement tasks.

[0037] The verification in S5 includes: performing a verification scan on the same reference cylindrical surface again, resolving the coordinates of the remeasured center, and calculating the residual modulus based on the remeasured center coordinates and the high-speed rotation center. As the retest residual, among which... For the coordinates of the remeasured center, The coordinates are for the center of high-speed rotation.

[0038] S6 includes: when the retest residual is greater than or equal to the preset residual allowable threshold, the abnormal status is sent back to the measurement controller of the gear measurement center, and the compensation parameters are rewritten when the scan is re-executed; when the number of consecutive recalibration failures reaches the preset number threshold, a shutdown alarm is triggered.

[0039] This embodiment discloses a method for calibrating the coordinate position of a gear measurement center. The method obtains the initial machine tool coordinate information and reference cylindrical surface parameters of the gear to be calibrated, and controls the C-axis to scan the same reference cylindrical surface at the first scanning speed and the second scanning speed to generate two sets of scanning point sets with speed differences.

[0040] A unified angle reference was established to separate the dynamic rotation center offset caused by changes in oil film thickness, and this offset was compensated to the machine tool coordinate transformation matrix in real time. The compensation effect was verified by a re-scan.

[0041] Step S1 is as follows: Obtain the initial machine tool coordinate information of the zero point of the machine tool and the zero position of the C-axis encoder of the reference measurement center control system of the gear to be calibrated, as well as the reference cylindrical surface parameters of the actual geometric features on the workpiece used for calibration. According to the current measurement task requirements, perform dual-speed continuous scanning of the gear to be calibrated at the first scanning speed for establishing the quasi-static oil film state and the second scanning speed for simulating the actual batch measurement conditions, and generate the first speed scanning point set and the second speed scanning point set.

[0042] Dual-speed scanning is performed on the same axial section of the same reference cylindrical surface, and the probe force, sampling frequency, clamping state and workpiece posture remain unchanged during the two scanning processes;

[0043] At each speed, the scanning point is recorded only after the C-axis reaches a stable speed. Data during the acceleration and deceleration transitions are not included in the first and second speed scanning point sets. Dual-speed continuous scanning involves completing two independent scans in the same clamping and task cycle. The two scans correspond to the data acquisition under their respective stable speed ranges. Data during the transition range is not included in either speed point set.

[0044] Before the scanned data enters the subsequent calculation, an independent data storage area is established inside the controller according to the speed state. Each storage area only receives probe points that are within the corresponding stable speed window.

[0045] The same sampling point, from the moment it enters the system, sequentially goes through the state transition of the stable interval to be confirmed, the valid measured point, the point to be mapped, the mapped point, the interpolation point, or the invalid discard point. Among them, the data marked as invalid discard points will no longer participate in the subsequent angle alignment and center calculation.

[0046] The controller starts writing to the corresponding temporary storage area only after detecting that the speed stabilization flag has been continuously satisfied for a preset duration, and immediately closes the writing window when the speed leaves the stable bandwidth, so that the first speed scan point set and the second speed scan point set are physically isolated during the acquisition phase.

[0047] The specific implementation method of step S2 is as follows: obtain the first speed scanning point set and the second speed scanning point set, take the zero position of the C-axis angle encoder as the angle reference, and according to the angle alignment rule of mapping discrete points collected at different speeds to the same polar angle sequence, perform angle domain mapping and interpolation to complete the two sets of points, and determine the data to be processed under the unified angle coordinates.

[0048] Divide one revolution of the C-axis into multiple equally spaced angular intervals, the number of intervals... According to the formula

[0049]

[0050] It is confirmed that, among them, Sampling frequency, The C-axis angular velocity is used to average or take the nearest neighbor value of the effective measured scanning points falling within the same angular interval, and this value is used as the mapped polar radius data of the corresponding node on the polar angle sequence. Interpolation is used to fill in the missing points caused by the mismatch between the sampling frequency and the rotation speed, which results in no measured points falling within the corresponding angular interval.

[0051] Missing angle points are only filled in for local continuous gaps. The preferred filling method is linear interpolation. The missing angle point data in the middle is calculated by using the effective measured data points at the two ends adjacent to the gap. The specific mapping and deduction rules are as follows: calculate the ratio of the angle difference between the missing angle point and the starting end of the gap to the entire angle width of the gap, and then perform linear weighting on the extreme diameter difference between the two ends based on this ratio and add it to the extreme diameter value of the starting end.

[0052] When a single continuous notch is greater than or equal to the preset angle width or the number of valid measured points after mapping is less than or equal to the preset minimum number of points, the scanning data of the wheel is determined to be invalid and step S1 is re-executed; wherein, the value of the preset angle width is based on 1.5 to 2 times the center angle corresponding to a single tooth pitch of the gear to be calibrated, in order to distinguish between normal missed sampling by the sensor and fractures and collisions on the workpiece surface that exceed the preset size.

[0053] The rule for determining the minimum number of preset points is the total number of theoretical full sampling points. 80% to 90%, the theoretical total number of sampling points is based on the formula

[0054]

[0055] The calculation shows that, The C-axis scanning angular velocity, The sampling interval is set to ensure the representativeness and confidence of the data samples in the subsequent first-order harmonic fitting calculation; the mapping process is performed in ascending order of the angle sequence, and the status flag of each angle interval is written immediately after the mapping is completed.

[0056] If the interval is formed by measured points, it is marked as a valid measured interval; if it is formed by interpolation, it is marked as a completed interval; if the continuous gap exceeds the limit, it is marked as a mismatched interval and the subsequent fitting of the current round is terminated. For multiple adjacent completed intervals, it is preferable to set a maximum continuous completed length. When the continuous completed length reaches the upper limit, the data flow of this round is directly interrupted to step S3, instead of continuing to rely on the interpolated data of continuous long intervals for center solving, so as to reduce the solution deviation caused by the missing continuous data.

[0057] The specific implementation method of step S3 is as follows: acquire the data to be processed, perform center calculation on the data to be processed according to the first-order harmonic fitting model, calculate the low-speed rotation center and the high-speed rotation center, determine the coordinate offset, and determine whether the coordinate offset meets the preset displacement threshold condition; the reference surface radius sequence is represented as:

[0058]

[0059] Based on the above formula, the inherent shape error of the workpiece surface and the offset of the rotation center are separated, which is derived from the first... Speed ​​state The measured reference surface radius corresponding to each sampling angle , No. Average radius of the reference surface under velocity conditions The first one obtained by synchronization from the C-axis encoder Each sampling angle The first harmonic coefficients characterize the first-order eccentric components of the probe's polarity signal in the X and Y directions. and And higher-order shape errors and noise terms, including local roughness of the gear surface. Together constitute;

[0060] The first harmonic coefficients can be obtained by least-squares fitting of effective measured points under a unified angular reference. The sum of squared residuals between the measured mapped polar radius and the fitted polar radius is used as the loss function, and its expression is as follows:

[0061]

[0062] By taking the partial derivative of the loss function and setting it to zero, the solution can be obtained. and The same angle sequence and fitting rules were used under both rotational speed conditions to ensure the comparability of the obtained center differences; the center coordinates were calculated.

[0063]

[0064] The above sign relationship takes the radial outward direction of the output polarity of the scanning probe along the machine tool as the positive direction, and The definition of positive C-axis increment is a prerequisite; if the measurement and control system adopts the opposite convention of positive polar radius or positive angle, then the corresponding first harmonic coefficients should be converted to the same sign before writing the compensation parameters, that is, the corresponding coefficients should be multiplied by... Perform a sign reversal to obtain the result. and The translation direction should be consistent with the positive direction of the machine tool's X and Y axes to avoid reverse compensation caused by opposite signs;

[0065] thus, and First, the coordinates are obtained in the measurement signal domain, then normalized to the machine tool coordinate system by direction convention, and finally obtained. and This avoids the ambiguity in coordinate meaning caused by directly mixing signal domain coefficients with machine tool translation; among them, ( , ) represents the coordinates of the low-speed rotation center. , ( ) represents the coordinates of the high-speed rotation center; calculate the coordinate offset:

[0066]

[0067]

[0068] and offset modulus

[0069]

[0070] offset modulus This refers to the dynamic rotation center displacement caused by changes in the oil film state after the C-axis switches from low-speed to working speed; the preset displacement threshold condition is determined by judging the offset modulus. Whether it is greater than or equal to the preset minimum displacement threshold and less than or equal to the preset maximum safe displacement limit;

[0071] The preset minimum displacement threshold is used to filter out inherent system noise. An example value is 3 times the minimum displacement threshold that the system can identify, such as 3 times the probe repeatability error. The maximum safe displacement limit is used to eliminate collision or clamping loose data that exceed the tolerance limit. Its value is based on the maximum mechanical clearance allowed by the clamping of the gear to be calibrated or the safe displacement tolerance limit of the machine tool C-axis design. An example value is 0.05mm to 0.1mm.

[0072] When the offset modulus When the displacement is less than the preset minimum displacement threshold, it indicates that the difference between the two speeds in this round is insufficient to reliably distinguish from system noise. The current result is treated as invalid calibration data and steps S1 to S3 are re-executed, instead of directly writing the result as a zero compensation value into the machine tool coordinate transformation matrix; when the offset modulus... If the displacement exceeds the preset maximum safe displacement limit, an abnormal working condition is determined and the process of re-collection and recalculation is initiated.

[0073] The preset minimum displacement threshold, provided it is not lower than the minimum displacement threshold that the system can recognize, is combined with the most recent The standard deviation of the low-speed fitting residuals during the second calibration Update; when the standard deviation is... When the fluctuation exceeds the preset threshold, the formula is used. Calculate and update the noise filtering threshold for this round, where, Based on the basic threshold, The preset gain coefficient; when the standard deviation When the value recovers to within the preset fluctuation threshold, the filtering threshold falls back to the basic threshold.

[0074] Correspondingly, the preset maximum safe displacement limit is preferred to always obey the mechanical safety upper bound, and its priority is higher than any noise adaptive threshold. Even if the minimum displacement threshold is dynamically raised due to noise changes, the interception logic of breaking through the mechanical safety upper bound is not allowed.

[0075] Step S4 is as follows: Obtain the coordinate offset, write the coordinate offset into the machine tool coordinate transformation matrix according to the preset machine tool kinematic model, and generate the corrected compensation parameters; without changing the original X / Y / Z axis servo control hardware structure of the machine tool, only the translation parameters corresponding to the C-axis rotation center are corrected at the software level, so that all subsequent gear tooth surface, tooth profile, and tooth direction measurement data can automatically call the compensation parameters to keep consistent with the actual rotation center at the working speed;

[0076] Furthermore, the preferred method for writing is a single correction based on the current effective matrix reference. That is, the coordinate offset obtained in this round is written based on the machine tool coordinate transformation matrix before the start of this calibration round; the three-dimensional homogeneous transformation matrix representing the C-axis spatial position in the measurement and control system is read, and the X-axis basic translation component and Y-axis basic translation component at the corresponding position are respectively superimposed with the X-axis offset obtained in this round. and Y-axis offset Generate a new coordinate transformation matrix;

[0077] When entering the recalibration process, the system is rewritten starting from the reference matrix or the most recently confirmed valid compensation parameters, without accumulating the temporary compensation amounts from the previous failed rounds, to avoid overcorrection caused by repeated compensation; the homogeneous transformation matrix in three-dimensional space is preferably a 4×4 matrix. and Only the X and Y translation terms in one column are written. The Z-direction translation terms and each rotation term remain unchanged in this round of calibration to ensure that the compensation object is limited to the translation offset of the C-axis rotation center in the measurement plane.

[0078] Furthermore, the compensation writing preferably adopts the sequential control of calculation completion—parameter freezing—single overwrite—post-write verification: after the effective offset is output in step S3, the current effective matrix is ​​frozen as the rollback reference, and then a single overwrite is performed. After the writing is completed, only the verification scan is allowed to read the latest effective parameters, while other measurement tasks are prohibited from concurrently rewriting the matrix before the verification ends. If the verification fails, it will directly roll back to the frozen reference and wait for the recalculation result of this round to rewrite, so as to avoid the unclear source of compensation amount or repeated superposition caused by cross-writing of different tasks.

[0079] The specific implementation methods of steps S5 and S6 are as follows: Obtain the corrected compensation parameters; according to the verification scan command, perform a verification scan again on the same reference cylindrical surface; re-solve the remeasured center coordinates; and calculate the remeasured residual, which characterizes the residual center offset after compensation, based on the remeasured center coordinates and the high-speed rotation center. The formula for calculating this remeasured residual is:

[0080]

[0081] In this calculation formula, the coordinates of the remeasured center are used. and the coordinates of the high-speed rotation center Solve for the residual value; to ensure that the residual is comparable to the aforementioned high-speed rotation center, the verification scan is preferably performed within the range after the second scan speed reaches a stable state, along the same reference cylindrical surface and the same axial section as in step S1, and using the same angle mapping, missing point processing and center calculation rules as in steps S2 and S3.

[0082] When the verification data has continuous gaps exceeding the preset width, or the number of valid measured points is less than the preset minimum number of points, the current verification is deemed invalid and the verification scan is re-executed instead of directly updating the compensation parameters. Furthermore, to avoid inconsistencies in the coordinate reference systems before and after compensation, which could lead to distortion in the residual comparison, the high-speed rotation center is preferably frozen and saved under the current valid coordinate transformation matrix reference before the start of this round of calibration.

[0083] Before calculating the remeasurement residual, the remeasurement center coordinates obtained from the verification should preferably be converted to the same coordinate reference as the high-speed rotation center, or the high-speed rotation center should be synchronously converted to the verification coordinate reference according to the coordinate transformation matrix written in this round before the difference is calculated, so as to ensure that the remeasurement center coordinates and the high-speed rotation center coordinates in the formula are under the same coordinate reference.

[0084] Unlike the method of directly entering the measurement after a single calibration, this application verifies the actual effective status of the compensation parameters by reviewing the scan and comparing the residuals, so that there is a result verification step after the parameters are issued; when the remeasured residual is less than the preset residual allowable threshold, the calibration result is output and the compensation parameters of this round are confirmed as valid parameters for subsequent gear measurement tasks.

[0085] When the retest residual is greater than or equal to the threshold, an abnormal status is sent back to the measurement controller and the compensation parameters are rewritten when the scan is re-executed; when the number of consecutive recalibration failures reaches the preset threshold (example value is 3 times), a shutdown alarm is triggered.

[0086] The embodiments of the present invention can achieve quantitative evaluation of the compensation effect based on the retest residual, avoiding the continued use of invalid compensation parameters in subsequent measurements; furthermore, the entire calibration process is preferably executed in the following order: waiting for clamping confirmation—low-speed stability detection—low-speed acquisition—high-speed stability detection—high-speed acquisition—central calculation—compensation writing—high-speed verification—result confirmation.

[0087] Each state has a maximum waiting time or a maximum number of retries. When the stability test fails to meet the requirements within the specified time, the number of collection points does not reach the minimum requirement, or the verification fails continuously to the upper limit, the process will no longer continue. Instead, it will switch to an abnormal feedback or shutdown alarm state. This ensures that scan triggering, compensation writing, and verification comparison all have clear preconditions and exit paths, avoiding reliance on abstract recalibration instructions and lack of engineering control loops.

[0088] Reference Figure 2 A gear measurement center coordinate position calibration system is provided for performing a gear measurement center coordinate position calibration method as described in the embodiment. The system is applied to a gear measurement center including a scanning probe, a C-axis, and a measurement controller. The system includes:

[0089] The data acquisition module is used to acquire the initial machine tool coordinate information and reference cylindrical surface parameters of the gear to be calibrated through the scanning probe and the measurement controller. It controls the C-axis to scan the gear to be calibrated at the first scanning speed and the second scanning speed, respectively, to obtain the first speed scanning point set and the second speed scanning point set.

[0090] The data classification module is used to classify the first speed scanning point set and the second speed scanning point set according to the preset angle alignment rules to obtain the data to be processed.

[0091] The deviation judgment module is used to calculate the low-speed rotation center based on the first rotational speed scan point set in the data to be processed, calculate the high-speed rotation center based on the second rotational speed scan point set, calculate the coordinate offset, and determine whether the coordinate offset meets the preset displacement threshold condition. The calibration execution module is used to write the coordinate offset into the machine tool coordinate transformation matrix and perform coordinate calibration when the preset displacement threshold condition is met, and to re-acquire data when the preset displacement threshold condition is not met. The result verification module is used to perform a verification scan on the reference cylindrical surface after coordinate calibration and calculate the difference between the re-measured center coordinates and the high-speed rotation center as the re-measured residual. When the re-measured residual is greater than or equal to the preset residual allowable threshold, the compensation parameters are corrected and recalibrated. The feedback module is used to update the coordinate compensation parameters based on the verification results.

[0092] The data acquisition module includes an acquisition submodule and a recording submodule for collecting and recording scan data;

[0093] The data classification module includes an angle alignment submodule for aligning angle domains and an interpolation padding submodule for filling in missing angle points;

[0094] The deviation judgment module includes a center calculation submodule for calculating the rotation center and an offset judgment submodule for judging displacement conditions;

[0095] The calibration execution module includes a matrix correction submodule for correcting the coordinate transformation matrix and a reacquisition submodule for reacquiring data;

[0096] The result verification module includes a verification scan submodule for performing verification scans and a residual comparison submodule for performing residual comparisons.

[0097] The feedback module includes a status feedback submodule for transmitting abnormal states, a parameter rewriting submodule for rewriting compensation parameters, and an abnormal handling submodule for triggering shutdown alarms.

[0098] This embodiment discloses a gear measurement center coordinate position calibration system, which corresponds to the calibration method in the above embodiment. In specific implementation, the data acquisition module synchronously acquires the trigger signal of the scanning probe, the C-axis angle encoder signal, and the speed stability signal through the acquisition sub-module and the recording sub-module, ensuring that the data acquisition at the first scanning speed and the second scanning speed are strictly aligned with the physical action.

[0099] Furthermore, it is preferred to enable data acquisition only within the stable speed range, and the data in the transition range is marked as invalid by the recording submodule; synchronous acquisition preferably uses the same measurement controller clock source to record the probe sampling event, encoder angle value and speed stability flag with a unified timestamp, or latches the stable state signal inside the controller before opening the data acquisition window, thereby avoiding mismatch between angle value and scanning point caused by communication delay differences between different acquisition links;

[0100] The data classification module, through the angle alignment submodule and the interpolation completion submodule, performs polar radius mean or nearest neighbor processing on the measured points according to the equal interval angle interval division rule, maps the discrete scan point set to a unified angle sequence, and uses the effective data of adjacent endpoints of the gap to perform linear weighting between the endpoint polar radii by calculating the weight ratio of the angle difference, and interpolates to fill in the missing data where no measured points fall.

[0101] When the missing angle range exceeds the preset width set according to the center angle of a single tooth pitch of the gear, or when the number of effective measured points is less than the preset minimum number of points of a specific proportion of the preset full sampling points, the re-acquisition submodule directly triggers the re-acquisition of data.

[0102] Furthermore, the deviation judgment module uses the center calculation submodule to perform first-order harmonic fitting on the data after mapping in the same domain. By constructing the residual sum of squares loss function and taking its partial derivative, the low-speed rotation center and high-speed rotation center are extracted. The offset judgment submodule calculates the dynamic coordinate offset and intercepts abnormal displacement data based on the set safety displacement tolerance limit of the machine tool C-axis design.

[0103] After the central calculation submodule outputs the first harmonic coefficients, the system preferably follows the positive direction convention of the machine tool's X and Y axes, by multiplying the corresponding first harmonic coefficients by... Complete the symbol conversion, then generate and To avoid reverse compensation when the positive direction of the probe's polar diameter is not defined in the same way as the positive direction of the machine tool's translation;

[0104] Therefore, the first output of the central calculation submodule is the first-order signal coefficient, which is then processed by coordinate direction normalization to obtain the center offset in the machine tool coordinate system. After the threshold condition is met, the calibration execution module writes the offset into the underlying kinematic transformation relationship of the measurement controller through the matrix correction submodule. Specifically, the X-axis offset and Y-axis offset are superimposed on the translation component corresponding to the homogeneous transformation matrix of the machine tool coordinate system to achieve translation compensation at the software level.

[0105] Write a single-overlay correction based on the current effective coordinate transformation matrix. During recalibration, the parameter rewriting submodule cancels the temporary compensation of the previous failed round and rewrites it according to the new result of this round to avoid the repeated accumulation of compensation.

[0106] The homogeneous transformation matrix of the machine tool coordinate system is preferably a 4×4 matrix. The matrix correction submodule only rewrites the X and Y translation components in one column, while the Z translation and rotation components remain unchanged, so that the compensation action and the in-plane center offset obtained in step S3 are consistent in data structure.

[0107] Finally, the result verification module performs a second scan on the compensated workpiece reference surface through the verification scan submodule and the residual comparison submodule to quantitatively evaluate the compensation effect. The verification scan is preferably performed within the stable range of the second scan speed, along the same reference cylindrical surface and the same axial section, and reuses the aforementioned angle alignment and center calculation rules.

[0108] To avoid distortion in residual comparison caused by switching of coordinate references before and after compensation writing, the system preferably has the recording submodule or parameter rewriting submodule freeze and save the coordinate reference identifier corresponding to the high-speed rotation center at the beginning of this round of calibration, and the residual comparison submodule converts the coordinates of the remeasurement center and the high-speed rotation center to the same coordinate reference before calculating the difference before calculating the remeasurement residual.

[0109] If the residual exceeds the limit, the feedback module triggers the recalibration process through the status feedback submodule and the parameter rewriting submodule; if the residual meets the threshold condition, the compensation parameters of this round are confirmed as valid parameters for subsequent measurement tasks; if the limit is exceeded continuously, the shutdown alarm is triggered through the abnormal handling submodule, thus forming a closed-loop control of acquisition-solution-compensation-verification-reiteration at the system architecture level.

[0110] Furthermore, in engineering implementation, the system preferably sets up independent data buffers within the controller that correspond one-to-one with the first scan speed, the second scan speed, and the verification stage, and adds process status identifiers to the data entering the buffers; the status identifiers are at least used to distinguish between measured points in the stable interval, invalid points in the transition interval, mapping completion points, interpolation completion points, and fitting failure points;

[0111] When the recording submodule detects that the rotation speed deviates from the stable bandwidth, the number of points on a single wheel is insufficient, or the continuous gap exceeds the limit, it directly changes the status flag of the corresponding data and blocks its flow to the central calculation submodule, instead of uniformly mixing and processing it in the backend, so that the data flow path is consistent with the control flow path.

[0112] Furthermore, the system preferably adopts a state machine control method that combines event-driven and timeout protection, including at least the following states: waiting for clamping, low-speed stability determination, low-speed acquisition, high-speed stability determination, high-speed acquisition, central calculation, compensation writing, verification acquisition, result confirmation, and abnormal handling. When switching from any state to the next state, the confirmation signal output by the previous state is used as the trigger condition.

[0113] For states that require waiting for physical actions to complete, it is preferable to set a maximum allowable waiting time. If no confirmation of stable rotation speed, sample quantity compliance, or compensation writing completion is received within this time, the feedback module will directly trigger re-acquisition or abnormal handling to prevent the system from remaining in an incomplete state for a long time. This enables the system to form a closed loop not only at the functional module level, but also at the timing control level, forming a deterministic execution chain with clear entry conditions, exit conditions, and failure fallback paths.

[0114] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calibrating the coordinate position of a gear measurement center, characterized in that, Includes the following steps: S1: Obtain the initial machine tool coordinate information and reference cylindrical surface parameters of the gear to be calibrated, and scan the gear to be calibrated at the first scanning speed and the second scanning speed respectively to obtain the first speed scanning point set and the second speed scanning point set; S2: According to the preset angle alignment rules, the first speed scanning point set and the second speed scanning point set are classified by angle reference to obtain the data to be processed. The data to be processed includes the aligned first speed scanning point set and the aligned second speed scanning point set. S3: Calculate the low-speed rotation center based on the aligned first rotational speed scan point set in the data to be processed, and calculate the high-speed rotation center based on the aligned second rotational speed scan point set, calculate the coordinate offset, and determine whether the coordinate offset meets the preset displacement threshold condition. S4: When the preset displacement threshold condition is met, the coordinate offset is written into the machine tool coordinate transformation matrix as a coordinate compensation parameter, and coordinate calibration is performed; when the preset displacement threshold condition is not met, steps S1 to S3 are re-executed. S5: Perform a verification scan on the reference cylindrical surface after coordinate calibration, and calculate the difference between the remeasured center coordinates and the high-speed rotation center as the remeasured residual; output the calibration result when the remeasured residual is less than the preset residual allowable threshold; when the remeasured residual is greater than or equal to the residual allowable threshold, correct the coordinate compensation parameters and recalibrate. S6: Update the coordinate compensation parameters based on the verification results.

2. The gear measurement center coordinate position calibration method according to claim 1, characterized in that, The initial machine tool coordinate information in S1 includes the machine tool zero point and the C-axis encoder zero position; the reference cylindrical surface parameters include the geometric parameters of the reference cylindrical surface; and it also includes the current measurement task number.

3. The gear measurement center coordinate position calibration method according to claim 2, characterized in that, The angle reference classification in S2 includes: setting an angle reference, using the zero position of the C-axis angle encoder as the angle reference, performing angle domain mapping according to a preset sampling interval, interpolating and filling in missing angle points, and aligning and classifying the mapped and filled first speed scanning point set and second speed scanning point set according to the same angle reference.

4. The gear measurement center coordinate position calibration method according to claim 1, characterized in that, The coordinate offset in S3 includes the X-axis offset. Y-axis offset and offset modulus At least one of them.

5. The gear measurement center coordinate position calibration method according to claim 4, characterized in that, The preset displacement threshold conditions in S3 include: the offset modulus value corresponding to the coordinate offset is greater than or equal to the preset minimum displacement threshold and less than or equal to the preset maximum safe displacement limit.

6. The method for calibrating the coordinate position of a gear measurement center according to claim 2, characterized in that, The coordinate calibration in S4 includes: writing the coordinate offset into the machine tool coordinate transformation matrix to correct the translation parameters corresponding to the rotation center of the C-axis, and calling the corrected compensation parameters in subsequent gear measurement tasks.

7. The gear measurement center coordinate position calibration method according to claim 1, characterized in that, The verification in S5 includes: performing a verification scan on the same reference cylindrical surface again, resolving the coordinates of the remeasured center, and calculating the residual modulus based on the remeasured center coordinates and the high-speed rotation center. As the retest residual, where... For the coordinates of the remeasured center, The coordinates are for the center of high-speed rotation.

8. The gear measurement center coordinate position calibration method according to claim 1, characterized in that, S6 includes: when the retest residual is greater than or equal to a preset residual allowable threshold, sending back an abnormal status to the measurement controller of the gear measurement center, and rewriting the compensation parameters when re-performing the scan; when the number of consecutive recalibration failures reaches a preset number threshold, triggering a shutdown alarm.

9. A gear measurement center coordinate position calibration system, used to perform a gear measurement center coordinate position calibration method as described in any one of claims 1-8, characterized in that, A system for use in a gear measurement center, comprising a scanning probe, a C-axis, and a measurement controller, the system includes: The data acquisition module is used to acquire the initial machine tool coordinate information and reference cylindrical surface parameters of the gear to be calibrated through the scanning probe and the measurement controller, and to control the C-axis to scan the gear to be calibrated at the first scanning speed and the second scanning speed, respectively, to obtain the first speed scanning point set and the second speed scanning point set; The data classification module is used to classify the first speed scanning point set and the second speed scanning point set according to the preset angle alignment rules to obtain the data to be processed. The deviation judgment module is used to calculate the low-speed rotation center based on the first rotational speed scanning point set in the data to be processed, calculate the high-speed rotation center based on the second rotational speed scanning point set, calculate the coordinate offset, and determine whether the coordinate offset meets the preset displacement threshold condition. The calibration execution module is used to write the coordinate offset into the machine tool coordinate transformation matrix and perform coordinate calibration when the preset displacement threshold condition is met, and to re-acquire data when the preset displacement threshold condition is not met. The result verification module is used to verify the reference cylindrical surface after coordinate calibration and calculate the difference between the remeasurement center coordinates and the high-speed rotation center as the remeasurement residual. When the remeasurement residual is greater than or equal to the preset residual allowable threshold, the compensation parameters are corrected and the recalibration is performed. The feedback module is used to update the coordinate compensation parameters based on the verification results.

10. A gear measurement center coordinate position calibration system according to claim 9, characterized in that, The data acquisition module includes an acquisition submodule and a recording submodule for collecting and recording scan data; The data classification module includes an angle alignment submodule for aligning angle domains and an interpolation completion submodule for filling in missing angle points. The deviation judgment module includes a center calculation submodule for calculating the rotation center and an offset judgment submodule for judging displacement conditions; The calibration execution module includes a matrix correction submodule for correcting the coordinate transformation matrix and a reacquisition submodule for reacquiring data; The result verification module includes a verification scanning submodule for performing verification scanning and a residual comparison submodule for performing residual comparison. The feedback module includes a status feedback submodule for transmitting abnormal states, a parameter rewriting submodule for rewriting compensation parameters, and an abnormal handling submodule for triggering shutdown alarms.

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