CN-121989102-A - Taper hole caliber measuring method based on-machine clamping error suppression

CN121989102ACN 121989102 ACN121989102 ACN 121989102ACN-121989102-A

Abstract

The application provides a taper hole caliber measuring method based on-machine clamping error suppression, which establishes a hierarchical cutter compensation mechanism by taking a confidence coefficient label attached to a measuring result as a decision basis, breaks through the limitation that larger errors are possibly introduced in low-quality data of traditional compensation, and also overcomes the problem of low efficiency of full manual intervention. And the three-gear classification enables the system to dynamically adjust the automation degree according to the data reliability, so that the processing efficiency is improved, the reliability under abnormal working conditions is ensured, and the cooperative control of automation and safety is realized. By continuously utilizing the real processing result to calibrate the evaluation standard, the confidence coefficient model can self-evolve along with the change of working conditions, so that the whole system has the closed loop iteration capability of measurement, compensation, learning and optimization, and the long-term operation precision and stability are continuously improved.

Inventors

YAN XIAOFEI
ZHANG YUXIN
JIA JIANHUA
WANG BAO
ZHAO JINXIA

Assignees

北京国铁联合科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260403

Claims (10)

1. The method for measuring the caliber of the taper hole based on-machine clamping error inhibition is characterized by comprising the following steps of: establishing a rigid association between the measuring device and a machine tool coordinate system, and executing an automatic zero return cycle to inhibit zero drift; The attitude of the device is monitored through a three-point spherical support and an inclination sensor, and a double-state differential measurement is adopted to decouple the flatness error of the upper surface of the workpiece; Fusing multipoint temperature sensing and individual deviation of the steel balls to perform cooperative compensation; Calculating confidence coefficient based on the multi-source process data and outputting a measurement result carrying a confidence coefficient label; and feeding back the measurement result to a numerical control system of the machine tool to realize automatic closed-loop adjustment of tool compensation.
2. The method of on-machine-clamping-error-suppression-based taper bore measurement according to claim 1, wherein establishing a rigid association of the measurement device with the machine tool coordinate system and performing an auto-zero cycle comprises: The measuring device is adsorbed on the end face of a main shaft of the machine tool, the device is attached to a reference surface stably through machine tool movement, the current machine tool coordinate value is recorded, and a first automatic zeroing cycle is executed to obtain an initial zero reference value Will be Binding the coordinate values of the machine tool with the current coordinate values of the machine tool and storing the coordinate values into a device memory, and establishing a traceable mapping relation between a device coordinate system and the coordinate system of the machine tool; after the subsequent caliber measurement is completed, according to the current first Secondary measurement results Confidence level of the test And a zero point reference value recorded before the current measurement Cutter compensation quantity fed back by combining numerical control system of machine tool With measured deviation of the compensated workpiece Dynamic estimation of zero drift compensation coefficients by a Kalman filter Zero reference value for correcting the next measurement ; Judging whether to continue The zero drift estimate of the secondary measurement exceeds a preset first threshold and the confidence level of the corresponding measurement is higher than a preset second threshold, If yes, triggering the verification measurement, and prompting to clean a reference surface or re-adsorbing the measurement device when the verification measurement fails; If not, waiting for the next auto-zero cycle.
3. The method for measuring the caliber of the taper hole based on the on-machine clamping error suppression according to claim 1, wherein the attitude of the device is monitored through a three-point spherical support and an inclination sensor, and a dual-state differential measurement is adopted, and the decoupling of the flatness error of the upper surface of the workpiece comprises the following steps: the three-point spherical support at the bottom of the measuring device is placed on the upper surface of a workpiece, and the inclination angle of the measuring device relative to the horizontal plane is monitored in real time through an inclination angle sensor And according to the current first Zero drift compensation coefficient calculated by secondary measurement And the current temperature Dynamically adjusting a qualification threshold for a gesture When (when) Greater than When the device is placed repeatedly, the device is prompted to be placed repeatedly until the requirement is met; Record a first displacement reading in the state of not placing the steel ball Recording a second displacement reading in a state in which the steel ball is placed Calculating the difference Simultaneously recording the difference in inclination angle between the two measurements And temperature difference ; Will be And Input Kalman filter as confidence factor for dynamically adjusting zero drift compensation coefficient And according to the updated weights of Adaptively determining the validity of the current difference and prompting a re-measurement when determined to be invalid.
4. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 2, wherein the zero drift compensation coefficient is dynamically estimated through the Kalman filter The method of (1) comprises: constructing a state space model of zero drift estimation, and setting a zero reference value As a state variable, the current first Secondary measurement results Confidence level of the test As an observation input, according to the confidence level Dynamically adjusting observed noise covariance matrix ; The tool compensation quantity fed back by the numerical control system of the machine tool With the actual measured deviation of the compensated workpiece As external control input, by establishing a coupling relation model of compensation effect and zero drift Mapping to a correction amount to the state observation value; In the prediction phase of Kalman filtering, according to the first Time interval of dual-state differential measurement used in secondary measurement And temperature variation Calculating state transition matrix, and in the updating stage of Kalman filtering, fusing multisource observation information and outputting optimum estimated value And will Feed forward to zero reference correction for the next measurement.
5. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 3, wherein the zero drift compensation coefficient is dynamically estimated through the Kalman filter The method of (1) comprises: constructing an extended state vector and referencing zero point values Attitude deviation sensitivity coefficient Rate of temperature drift Jointly used as a state to be estimated; in the updating phase of Kalman filtering, according to And Dynamically adjusting observed noise covariance matrix When (1) diagonal elements of Greater than dynamic threshold Or (b) When the preset range is exceeded, the corresponding increase is made A value of a corresponding dimension; the zero reference component in the state estimation value obtained after filtering is taken as corrected zero reference component Outputting the attitude deviation sensitivity coefficient Feedback to dynamic threshold And the generating module is used for optimizing the gesture qualification threshold value of the next period.
6. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 3 or 5, wherein the attitude qualification threshold is dynamically adjusted Comprising the following steps: sensitivity coefficient of attitude deviation Current temperature And the historical confidence sequence is input into a weighted fusion function to generate a reference threshold value of the next period ; Mining historical measurement data by association rules to identify differences Optimal attitude control interval under value interval Using the interval as a priori knowledge for constraint threshold generation of the next period; According to Introducing a relaxation factor into the historical fluctuation variance of the model To dynamically adjust Time-of-day attitude eligibility threshold 。
7. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 3, wherein the step of combining multipoint temperature sensing and individual deviation of the steel ball for collaborative compensation comprises the following steps: According to the difference Dynamically adjusting the sampling frequency and fusion weight of each temperature sensor; Involving calculation by steel balls in history measurements Sequence, regression analysis is carried out to identify the abrasion rate of the steel ball, and the diameter deviation of the steel ball is dynamically corrected; Substituting the integrated temperature after fusion and the corrected steel ball diameter deviation into the same geometric model to carry out cooperative compensation, and outputting corrected displacement 。
8. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 7, wherein calculating the confidence based on the multi-source process data and outputting a measurement result carrying a confidence label comprises: collecting multisource process data including outputting the corrected displacement amount Measurement consistency of each temperature sensor in the process, steel ball abrasion regression residual error and inclination angle difference Difference in displacement Difference in temperature To construct a confidence assessment vector; inputting the confidence evaluation vector into a pre-trained fuzzy neural network model, and calculating the comprehensive confidence by combining the historical measurement statistical distribution And according to A value dividing the measurement result into corresponding confidence levels; outputting the measurement result carrying the confidence label to the machine tool numerical control system, and outputting the confidence Feedback to Kalman filter for dynamically adjusting the zero drift compensation coefficient of the next round Is used to update the weights of the (c).
9. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 8, wherein feeding back the measurement result to a numerical control system of a machine tool, and realizing automatic closed-loop adjustment of tool compensation comprises: According to the confidence label carried in the measurement result, a hierarchical cutter compensation strategy is adopted, and when automatic compensation is triggered, the following actions are executed: deviation value of measured diameter and target diameter for caliber measurement of workpiece The self-adaptive compensation controller is input into a numerical control system of the machine tool, and the compensation target model is identified on line through a recursive least square method by combining the historical compensation quantity sequence and the actual measurement deviation sequence after compensation, so that the compensation gain coefficient of the time is dynamically adjusted; and writing the measurement result, the confidence coefficient label, the compensation quantity, the actual measurement deviation after compensation and the time stamp of each compensation into a blockchain memory card, and inputting the actual measurement deviation after compensation into the fuzzy neural network model as feedback for optimizing a confidence coefficient grading threshold.
10. The method for measuring the caliber of the taper hole based on-machine clamping error suppression according to claim 9, wherein the fuzzy neural network model calculates the comprehensive confidence coefficient Comprising the following steps: An input layer of a fuzzy neural network model is built, the confidence evaluation vector is received, all input components are blurred into three fuzzy sets of low, medium and high through membership functions, and fuzzy rule bases are utilized to infer the input fuzzy sets, so that fuzzy output of the middle layer is obtained; Performing parameter optimization on the fuzzy output of the middle layer through a back propagation algorithm of a neural network, taking sample data with known accuracy in history measurement as a training set, taking the compensated actual measurement deviation as a verification tag, and adjusting the center and width of a posterior piece parameter and membership function of a fuzzy rule through a gradient descent method; and taking the statistical distribution characteristics of the actual measurement deviation sequence after compensation as a feedback signal, and dynamically adjusting a confidence grading threshold.

Description

Taper hole caliber measuring method based on-machine clamping error suppression Technical Field The application relates to the technical field of machining, in particular to a taper hole caliber measuring method based on-machine clamping error suppression. Background In the field of machining, taper hole parts such as machine tool spindle taper holes, fixture positioning taper holes and the like are widely applied to various precision equipment. Taking the machining of a part with a specified model as shown in FIG. 1 as an example, the size of the aperture of the taper hole reaches the requirementIs used for the high-precision level of (a), strict process quality control is required in mass production. Currently, an off-line three-coordinate measurement scheme is generally adopted for detecting such high-precision taper holes. The operation flow of the scheme is that the processed part is disassembled from a machine tool workbench, is conveyed to a special measuring chamber controlled by constant temperature after being cleaned, is arranged on the workbench of a three-coordinate measuring machine, carries out multi-point scanning on the inner surface of a taper hole through a measuring head, collects three-dimensional point cloud data, and calculates geometrical parameters such as the diameter, the taper and the like of an orifice through special measuring software fitting. However, this off-line three-coordinate measurement scheme has the following drawbacks in practical production applications: In the machining debugging stage, a technician needs to repeatedly adjust machine tool parameters according to the measurement result, which means that the same workpiece needs to undergo multiple cycles of machining, disassembly, measurement, reinstallation and reprocessing. Even if a high-precision hydraulic or pneumatic clamp is adopted for re-clamping each time, it is difficult to ensure that the workpiece coordinate system and the machine tool coordinate system are completely restored to the state before disassembly. Moreover, the clamping errors are superposition of randomness and systematicness, and are difficult to effectively compensate through subsequent process adjustment. Even if other on-machine measurement means are considered, the following problems are difficult to solve: 1. When the measuring tool is placed on the upper surface of the workpiece for measurement, the flatness error of the upper surface of the workpiece can be directly superimposed into a measurement result, and the flatness error is overlapped with the size error of the measured cone hole and cannot be separated. Meanwhile, absolute level is difficult to ensure when the measuring tool is placed, and systematic deviation can be introduced due to small installation inclination. Cutting heat, environmental temperature fluctuation and the like in a processing site can also cause thermal deformation of a machine tool spindle, a workpiece and measurement work to different degrees, and the thermal errors are directly ignored in the existing measurement scheme, so that the measurement reliability is reduced. 2. The traditional detection work generally adopts a single reading and single measuring mode, lacks an internal checking mechanism for the effectiveness of the measuring process, and when abnormal conditions such as unexpected shaking of tools, instantaneous fluctuation of reading and the like occur in the measuring process, the abnormal conditions cannot be identified by single measurement, so that the reliability of an output result cannot be ensured. 3. The measurement results obtained by the existing scheme are not related to the machine tool coordinate system. When the measurement result shows that the dimension deviates from the target value, the compensation amount of which axis should be adjusted and the adjustment amount are needed to be manually judged, and then the parameters of the machine tool are manually modified, so that the efficiency is low, and secondary errors are easy to be introduced. Disclosure of Invention The application realizes in-situ, real-time and reliable measurement of the aperture of the taper hole on the premise of not disassembling a workpiece, effectively inhibits various error factors caused by the clamping state, realizes closed-loop linkage of a measurement result and a machine tool control system, and improves the production efficiency and the production quality, and provides the aperture measuring method of the taper hole based on-machine clamping error inhibition. To achieve the purpose, the application adopts the following technical scheme: the utility model provides a taper hole caliber measuring method based on-machine clamping error inhibition, which comprises the following steps: establishing a rigid association between the measuring device and a machine tool coordinate system, and executing an automatic zero return cycle to inhibit zero drift; The attitude of the device is monitored throug