CN-122007980-A - Synchronous detection device, system and method for space and thermal errors of numerical control machine tool

CN122007980ACN 122007980 ACN122007980 ACN 122007980ACN-122007980-A

Abstract

The invention discloses a synchronous detection device, a synchronous detection system and a synchronous detection method for space and thermal errors of a numerical control machine tool, and relates to the field of machine tool error detection. The measuring head comprises a base plate, a zero point positioning system, a plurality of standard ball measuring tools which are arranged along an S-shaped curve and are gradually increased in height, a measuring head assembly which comprises a tool handle and a measuring head body arranged at the end part of the tool handle, three displacement sensors which are mutually orthogonal in axes and are directed to the center of the measuring head body are uniformly distributed on the measuring head body along the circumference, a time-sharing driving control unit which is used for controlling the three sensors to sequentially start sampling, and an upper computer which is used for receiving sampling data and performing space coupling analysis. According to the invention, the full working space is covered by the S-shaped space incremental layout, the time-sharing driving is adopted to avoid electromagnetic interference of multiple sensors, the zero point positioning system is utilized to realize rapid high-precision repeated clamping, and the synchronous decoupling of the space error and the thermal error is realized by the cold state/thermal state repeated measurement.

Inventors

YAO JUN
ZHONG HAO
YANG HAILONG
BAI YU
DU BAORUI

Assignees

中国科学院工程热物理研究所

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (10)

1. The utility model provides a digit control machine tool space and synchronous detection device of thermal error which characterized in that includes: A substrate; the zero point positioning system comprises a plurality of zero point positioner female seats fixed on the substrate; The bottom of each standard ball measuring tool is integrated with a positioning blind rivet matched with the zero point positioner female seat, and the standard ball measuring tools are arranged on the substrate along an S-shaped curve and have incremental heights in the direction vertical to the substrate; The measuring head assembly comprises a cutter handle and measuring heads arranged at the end parts of the cutter handle, wherein three displacement sensors are uniformly distributed on the measuring heads along the circumference, and the axes of the three displacement sensors are mutually orthogonal and point to the center of the measuring head; The time-sharing driving control unit is used for controlling the three displacement sensors to sequentially start sampling at each measuring position so as to avoid electromagnetic interference; And the upper computer is used for receiving the sampling data of the displacement sensor and performing space coupling analysis to calculate the displacement difference between the center of the measuring head and the center of the standard ball.
2. The synchronous detection device for the space and the thermal error of the numerical control machine tool according to claim 1, wherein the repeated positioning precision of the zero point positioning system is less than or equal to 2 mu m, the tensioning force of a single positioning blind rivet is more than or equal to 10kN, and the zero point positioner female seat and the positioning blind rivet adopt a short cone matching structure or a steel ball locking structure.
3. The synchronous detection device for the space and the thermal error of the numerical control machine tool according to claim 1, wherein the standard ball measuring tool comprises a standard ball, a ball rod and a positioning blind rivet, the standard ball is in threaded connection with the ball rod, the ball rod is in threaded connection with the positioning blind rivet, and a spigot positioning structure or a cylindrical pin positioning structure is arranged at the joint of the ball rod and the positioning blind rivet.
4. The synchronous detection device for the space and the thermal error of the numerical control machine tool according to claim 1, wherein the displacement sensor is an eddy current displacement sensor, the linearity of the eddy current displacement sensor is less than or equal to +/-0.1% of F.S., the resolution is less than or equal to 0.05% of F.S., and the measuring range is 0.5mm-2mm.
5. The synchronous detection device for the space and the thermal error of the numerical control machine tool according to claim 1, wherein the time-sharing driving control unit comprises a high-frequency switching circuit, and the high-frequency switching circuit controls three displacement sensors to sequentially complete single-channel sampling in microsecond time.
6. A synchronous detection system of space and thermal error of a numerical control machine tool is characterized by comprising: the synchronous detection device for space and thermal errors of a numerical control machine tool according to any one of claims 1 to 5, and The measuring path control module is used for controlling a machine tool spindle to drive the measuring head assembly to sequentially pass through each standard ball measuring tool along the S-shaped machining program for measurement; The error decoupling module is used for executing the first measurement program under the cold state of the machine tool to obtain a reference space error, repeatedly executing the measurement program under different hot states after the machine tool runs and generates heat to obtain a comprehensive space error of the coupling heat error, and identifying the time-varying heat error through a data comparison and separation algorithm to realize synchronous decoupling of the space error and the heat error.
7. The synchronous detection system of space and thermal errors of a numerical control machine according to claim 6, wherein the error decoupling module specifically comprises: the machine tool kinematic chain modeling unit is used for establishing a kinematic chain based on a machine tool structure and defining an error transmission path; the error element analysis unit is used for determining geometric error elements and thermal error elements; the comprehensive error model construction unit is used for constructing a comprehensive error mathematical model based on positive kinematic operation and the homogeneous coordinate transformation matrix; and the error separation unit is used for separating the pure space error and the pure heat error by performing decoupling calculation on repeated measurement data and the comprehensive error mathematical model based on the time-invariant characteristic of the space error and the time-variant characteristic of the heat error.
8. A method for synchronously detecting space and thermal errors of a numerical control machine tool, which is applied to the device as claimed in any one of claims 1 to 5 or the system as claimed in any one of claims 6 to 7, and is characterized by comprising the following steps: S1, installing a plurality of standard ball measuring tools on a substrate along an S-shaped curve in a height increasing manner through a zero point positioning system; S2, mounting the measuring head assembly on a machine tool spindle, and calibrating mounting eccentricities of three displacement sensors through a spindle rotation self-calibration method to generate a calibration matrix; S3, under the cold state of the machine tool, the control main shaft drives the measuring head assembly to sequentially pass through each standard ball measuring tool along the S-shaped processing program, and the time-sharing driving control unit controls the three displacement sensors to sequentially start sampling at each measuring position, so that the spherical center coordinates of each standard ball measuring tool are obtained as reference data; S4, operating the machine tool to a heating state, and repeatedly executing the step S3 to obtain spherical center coordinate data of each standard spherical measuring tool in different heating states; And S5, based on the data acquired in the steps S3 and S4, combining the comprehensive error mathematical model, and separating the space error and the thermal error.
9. The method for synchronously detecting the space and the thermal error of the numerically-controlled machine tool according to claim 8, wherein the spindle rotation self-calibration method in step S2 comprises: aligning the measuring head assembly with any standard ball measuring tool, keeping the coordinates motionless, and controlling the spindle to rotate for 360 degrees; recording waveform data of readings of three displacement sensors along with the change of the rotation angle; Performing least square circle fitting on the waveform data, and calculating the eccentricity and phase deviation between the actual rotation center of the measuring head and the sensing surface of each displacement sensor; and generating a calibration matrix according to the calculation result, and automatically deducting the installation error in the subsequent measurement.
10. The synchronous detection method of space and thermal errors of a numerically-controlled machine tool according to claim 8, wherein the mathematical model of the integrated error in step S5 is: Wherein, the As a result of the integrated error at the temperature T, In the event of a spatial error, For the coefficient of thermal deformation, Is the temperature variation; By simultaneous solution of cold state measurement data and at least two different hot state measurement data, the method obtains And (3) with Decoupling of spatial errors and thermal errors is achieved.

Description

Synchronous detection device, system and method for space and thermal errors of numerical control machine tool Technical Field The invention relates to the technical field of machine tool error detection, in particular to a device, a system and a method for synchronously detecting space and thermal errors of a numerical control machine tool. Background Five-axis numerical control machine tools are core equipment of modern manufacturing industry, and the machining precision of the five-axis numerical control machine tools directly influences the quality of products. Among the numerous sources of errors affecting the machine tool machining accuracy, spatial errors caused by machine tool geometry imperfections and thermal errors caused by variations in heat sources are major factors, wherein thermal errors can account for 40% to 70% of the total error under certain precision machining conditions. Although thermal error compensation techniques are widely used, the efficient implementation of such techniques requires efficient and accurate measurement of spatial and thermal errors. The existing widely used machine tool error detection devices such as the laser interferometer and the club instrument have inherent defects that the laser interferometer is high in cost, complex in installation and debugging and time-consuming in measurement process, a single measurement cannot cover a full working space and a temperature range, and the club instrument is relatively fast in installation, but mainly performs two-dimensional plane circular track test, is difficult to comprehensively represent three-dimensional space errors and cannot synchronously measure thermal errors. In the prior art, the space error and the thermal error of the machine tool are difficult to obtain simultaneously in the process of one-time clamping and measurement, the efficiency is low in the process of measuring in batches, and the actual working condition of geometric-thermal coupling cannot be truly reflected by measurement data. Therefore, there is a need in the art for an error detection scheme capable of simultaneously measuring a spatial error and a thermal error, so as to overcome the defects of complicated installation, low measurement efficiency, and difficulty in synchronously measuring the spatial error and the thermal error in the prior art. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a device, a system and a method for synchronously detecting space and thermal errors of a numerical control machine tool, which realize one-time clamping full-working space measurement and synchronous decoupling of space errors and thermal errors through the combined design of S-shaped space layout, three-sensor time-sharing driving and a zero point positioning system. In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect, the present invention provides a device for synchronously detecting space and thermal errors of a numerically-controlled machine tool, including: The zero point positioning system comprises a plurality of zero point positioner female seats fixed on the base plate, a plurality of standard ball measuring tools, a positioning blind rivet, a measuring head assembly, a time-sharing driving control unit and an upper computer, wherein the positioning blind rivet is integrated at the bottom of each standard ball measuring tool and matched with the zero point positioner female seats, the standard ball measuring tools are arranged on the base plate along an S-shaped curve and have incremental heights in the direction perpendicular to the base plate, the measuring head assembly comprises a cutter handle and a measuring head arranged at the end part of the cutter handle, three displacement sensors are uniformly distributed on the measuring head along the circumference, the axes of the three displacement sensors are mutually orthogonal and point to the center of the measuring head, the time-sharing driving control unit is used for controlling the three displacement sensors to sequentially start sampling at each measuring position so as to avoid electromagnetic interference, and the upper computer is used for receiving sampling data of the displacement sensors and carrying out space coupling analysis so as to calculate displacement difference between the center of the measuring head and the center of the standard ball. Furthermore, the repeated positioning precision of the zero point positioning system is less than or equal to 2 mu m, the tensioning force of a single positioning blind rivet is more than or equal to 10kN, and the zero point positioner female seat and the positioning blind rivet adopt a short cone matching structure or a steel ball locking structure. Further, the standard ball measuring tool comprises a standard ball, a ball rod and a positioning blind rivet, wherein the standard ball is in threaded connection with the ball rod,