CN113446972A

CN113446972A - Calibration method and calibration device for CMM probe system

Info

Publication number: CN113446972A
Application number: CN202110696010.3A
Authority: CN
Inventors: 国鑫; 王辉; 周烽; 金春水
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2021-09-28

Abstract

In the calibration method and device for a CMM probe system provided by the present application, a laser sensor is installed on the probe working platform, and the laser beam emitted by the laser sensor is aimed at the apex of the probe; The standard target ball is installed on the working platform, and the position of the standard target ball is fitted by adjusting the three-degree-of-freedom motion platform; the probe and the standard target ball are adjusted to touch in different directions, so that the laser sensor perceives the target ball. The displacement of the flexible sheet body is described to establish a coordinate change equation system; by means of least squares fitting, the coordinate transformation matrix in the coordinate change equation is solved, and then the deformation amount of the probe when detecting the object to be measured is obtained. The method does not need to consider the absolute position and direction of the probe ball, but only needs to determine the surface features and geometric features of the measured object according to the relative position and direction, which simplifies the calibration complexity and can effectively use the standard ball to measure the six degrees of freedom displacement of the probe. change, so as to realize the measurement of the measurement coordinate point and complete the rapid calibration of the probe.

Description

Calibration method and calibration device for CMM probe system

Technical Field

The invention belongs to a high-precision three-coordinate measuring system, and particularly relates to a calibration method and a calibration device for a CMM probe system.

Background

The probe applied to the high-precision three-coordinate measuring system usually needs higher manufacturing precision, and in addition, the actual spherical center position and direction of the probe can be well calibrated by a method of fitting the spherical center and binocular calibration mostly when the probe is calibrated. However, the work occasions requiring probe processing or measurement are all occasions with high precision requirements, and the high-precision probes need to be frequently replaced, so that the high-precision probe calibration needs to be carried out for multiple times. The existing probe calibration process is a more complicated and complicated process.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a calibration method and a calibration apparatus for a CMM probe system, which simplify the probe calibration process.

In order to solve the problems, the invention adopts the following technical scheme:

a method of calibrating a CMM probe system, comprising the steps of:

providing a probe, wherein the probe is arranged on a probe working platform and comprises a flexible sheet body;

a laser sensor is arranged on the probe working platform, and a laser beam emitted by the laser sensor is aligned at the top point of the probe;

installing a standard target ball on the probe working platform, and fitting the position of the standard target ball by adjusting a three-degree-of-freedom motion platform positioned right below the standard target ball;

adjusting the probe to touch the standard target ball in different directions, so that the laser sensor senses the displacement of the flexible sheet body to establish a coordinate change equation set;

and solving a coordinate transformation matrix in a coordinate transformation equation by a least square fitting mode, and further obtaining the deformation of the probe when the probe detects the measured object.

In some embodiments, the number of the laser sensors is three, and the laser sensors are respectively mounted on the probe working platform in a mutually perpendicular manner.

In some of these embodiments, the laser sensor senses displacement of the flexible sheet at 120 degrees in a direction of 1 micron.

In some embodiments, a plane mirror is further installed on the probe working platform, and the plane mirror can aim the laser beam emitted by the laser sensor at the vertex of the probe. In addition, the present application also provides a calibration apparatus for a CMM probe system, comprising: the probe comprises a flexible sheet body and a laser sensor arranged on the probe working platform, a laser beam emitted by the laser sensor is aligned to the vertex of the probe and is arranged on a standard target ball on the probe working platform, and the position of the standard target ball can be fitted by adjusting the three-degree-of-freedom motion platform;

the probe and the standard target ball are adjusted to touch in different directions, so that the laser sensor senses the displacement of the flexible sheet body to establish a coordinate change equation set, a coordinate transformation matrix in the coordinate change equation is solved in a least square fitting mode, and the deformation of the probe when a measured object is detected is further obtained.

In some embodiments, a plane mirror is further installed on the probe working platform, and the plane mirror can aim the laser beam emitted by the laser sensor at the vertex of the probe.

The technical scheme adopted by the application has the following effects:

according to the calibration method and device for the CMM probe system, a laser sensor is installed on a probe working platform, and a laser beam emitted by the laser sensor is aligned to the top point of a probe; installing a standard target ball on the probe working platform, and fitting the position of the standard target ball by adjusting the three-degree-of-freedom motion platform; adjusting the probe to touch the standard target ball in different directions, so that the laser sensor senses the displacement of the flexible sheet body to establish a coordinate change equation set; according to the method, the absolute position and the direction of the probe are not needed to be considered, only the surface characteristics and the geometric characteristics of the measured object are determined according to the relative position and the direction, the calibration complexity is simplified, the standard ball can be effectively utilized to measure the displacement change of 6 degrees of freedom of the probe, and therefore the measurement of the measurement coordinate point is realized, and the rapid calibration work of the probe is completed.

In addition, this application is demarcated the probe and is measured, turns into the coordinate variable quantity of cartesian coordinate system, compensates to the interferometer in, therefore the probe can have fluctuation of certain extent in touching, and its result does not influence holistic accuracy.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart illustrating steps of a calibration method of a CMM probe system according to embodiment 1 of the present invention.

Fig. 2 is a schematic structural diagram of a calibration apparatus of a CMM probe system according to embodiment 2 of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "horizontal", "inside", "outside", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

Example 1

Referring to fig. 1, a flowchart of steps of a calibration method for a CMM probe system according to embodiment 1 of the present application includes the following steps:

step S110: providing a probe, wherein the probe is arranged on a probe working platform and comprises a flexible sheet body;

step S120: and a laser sensor is arranged on the probe working platform, and a laser beam emitted by the laser sensor is aligned at the vertex of the probe.

Step S130: and mounting a standard target ball on the probe working platform, and fitting the position of the standard target ball by adjusting a three-degree-of-freedom motion platform positioned right below the standard target ball.

Step S140: and adjusting the probe to touch the standard target ball in different directions, so that the laser sensor senses the displacement of the flexible sheet body to establish a coordinate change equation set.

Step S150: and solving a coordinate transformation matrix in a coordinate transformation equation by a least square fitting mode, and further obtaining the deformation of the probe when the probe detects the measured object.

It is understood that the above steps S130-S150 are repeated using the newly calibrated coordinate transformation matrix to improve the accuracy of the coordinate transformation matrix.

According to the calibration method of the CMM probe system, the absolute position and the direction of the probe do not need to be considered, the surface characteristic and the geometric characteristic of a measured object only need to be determined according to the relative position and the direction, the calibration complexity is simplified, and the 6-degree-of-freedom displacement change of the probe can be effectively determined by using the standard ball, so that the measurement of a measurement coordinate point is realized, and the rapid calibration work of the probe is completed.

Example 2

Referring to fig. 2, a schematic diagram of a calibration apparatus of a CMM probe system according to embodiment 2 of the present application is provided, which includes: the probe comprises a flexible sheet body and a laser sensor arranged on the probe working platform, a laser beam emitted by the laser sensor is aimed at the vertex of the probe and is arranged on a standard target ball on the probe working platform, and the standard target ball position can be fitted by adjusting a three-degree-of-freedom motion platform.

Three portions A, B, C represent the flexible sheet portions, which are distributed at 120 degrees, and three laser sensors sense the displacement of the flexible sheet. In the main step three, collision in four directions is mainly in the direction of value A, B, C, Z, and displacement vectors are respectively (1,0,0),

(0,0,-1)。

The application provides a calibration device of CMM probe system need not consider probe absolute position and direction, only needs to confirm the surface characteristic and the geometric characteristics of testee according to relative position and direction, has simplified the demarcation complexity, can effectually utilize 6 degrees of freedom displacement changes of standard ball survey probe to the realization is measured measurement coordinate point, accomplishes the quick demarcation work of probe.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. a calibration method of a CMM probe system, is characterized in that, comprises the following steps:

Step S110: provide a probe, the probe is installed on the probe working platform, and the probe includes a flexible sheet body;

Step S120: A laser sensor is installed on the probe working platform, and the laser beam emitted by the laser sensor is aimed at the vertex of the probe;

Step S130: install a standard target ball on the probe working platform, and adjust the three-degree-of-freedom motion platform directly below the standard target ball to fit the standard target ball position;

Step S140: adjusting the probe and the standard target ball to touch in different directions, so that the laser sensor senses the displacement of the flexible sheet, so as to establish a coordinate change equation system;

Step S150: Solve the coordinate transformation matrix in the coordinate change equation by means of least squares fitting, and then obtain the deformation amount of the probe when detecting the object to be measured.

2 . The method for calibrating a CMM probe system according to claim 1 , wherein the number of the laser sensors is three, and they are respectively installed on the probe working platform so as to be perpendicular to each other. 3 .

3 . The method for calibrating a CMM probe system according to claim 1 , wherein the laser sensor senses the displacement of the flexible sheet body at 1 micrometer in the 120-degree distribution direction. 4 .

4. The method for calibrating a CMM probe system according to claim 1, wherein a plane reflection mirror is also installed on the probe working platform, and the plane reflection mirror can illuminate the laser beam emitted by the laser sensor. Align at the apex of the probe.

5. the calibration method of CMM probe system according to claim 1, is characterized in that, also comprises the following steps:

According to the newly calibrated coordinate transformation matrix, the above steps S130-S150 are repeated.

6. A calibration device for a CMM probe system, characterized in that it comprises: a probe working platform, a probe installed on the probe working platform, and the probe comprises a flexible sheet body and is installed on the probe. The laser sensor on the needle working platform, the laser beam emitted by the laser sensor is aimed at the standard target ball installed on the probe working platform at the apex of the probe. The three-degree-of-freedom motion platform below can fit the standard target ball position;

By adjusting the probe and the standard target ball to touch in different directions, the laser sensor senses the displacement of the flexible sheet, so as to establish a coordinate change equation system, and solve the coordinates by means of least squares fitting The coordinate transformation matrix in the change equation is used to obtain the deformation amount of the probe when detecting the object to be measured.

7 . The calibration device of the CMM probe system according to claim 6 , wherein the number of the laser sensors is three, and they are respectively installed on the probe working platform so as to be perpendicular to each other. 8 .

8 . The calibration device of the CMM probe system according to claim 6 , wherein the laser sensor senses the displacement of the flexible sheet body at 1 micrometer in the 120-degree distribution direction. 9 .

9 . The calibration device of the CMM probe system according to claim 6 , wherein a plane mirror is also installed on the probe working platform, and the plane mirror can illuminate the laser beam emitted by the laser sensor. 10 . Align at the apex of the probe.