CN113188494B

CN113188494B - Calibration system and measurement method thereof

Info

Publication number: CN113188494B
Application number: CN202110423764.1A
Authority: CN
Inventors: 张鹏; 肖田
Original assignee: Chotest Technology Inc
Current assignee: Chotest Technology Inc
Priority date: 2021-04-20
Filing date: 2021-04-20
Publication date: 2023-03-10
Anticipated expiration: 2041-04-20
Also published as: WO2022222521A1; CN113188494A

Abstract

The invention provides a calibration system which comprises a calculation unit, an optical transmitting and receiving device, a reflecting mirror, a rotary table and a guide rail, wherein the reflecting mirror is arranged at the center of the rotary table, the guide rail is connected with a guide rail sliding block, the optical transmitting and receiving device is arranged on the guide rail sliding block, the optical transmitting and receiving device is suspended right above the reflecting mirror, and the optical transmitting and receiving device is connected with the calculation unit. The invention also provides a measuring method of the calibration system. The invention has the beneficial effects that: the included angle data of the guide rail motion axis and the rotary table rotation axis can be accurately collected.

Description

Calibration system and measurement method thereof

Technical Field

The invention relates to a precision measuring instrument, in particular to a calibration system and a measuring method of the calibration system.

Background

In a precision measuring instrument, especially in a cylindrical coordinate measuring system, it is often necessary that a guide rail movement axis Z is parallel to a turntable rotation axis θ, as shown in fig. 1, so as to form an ideal cylindrical coordinate system to realize precision measurement. However, in practice, however adjusted, there must be a spatial angle α between the axis of motion of the guide rail and the axis of rotation of the turntable, which angle is generally not accurately measured nor compensated for because both axes are virtual.

The conventional method is to use a standard cylinder for adjustment, to make the center of the standard cylinder pass through the axis of the turntable by repeated adjustment, and then to adjust the standard cylinder to make the motion axis of the guide rail parallel to the center of the standard cylinder, so as to achieve the purpose that the motion axis of the guide rail is parallel to the rotation axis of the turntable.

The problems existing in the prior art are as follows:

1) After the adjustment is finished, clear included angle data cannot be obtained, and high-precision compensation is difficult to perform.

2) Because clamp data cannot be obtained, the parallelism needs to be adjusted to an ideal level as much as possible, repeated adjustment is needed, the efficiency is low, and an ideal effect is difficult to achieve;

disclosure of Invention

In order to solve the problems in the prior art, the invention provides a calibration system and a calibration method, which can accurately acquire the data of the included angle between the motion axis of a guide rail and the rotation axis of a turntable.

The invention provides a calibration system which comprises a calculation unit, an optical transmitting and receiving device, a reflecting mirror, a rotary table and a guide rail, wherein the reflecting mirror is arranged at the center of the rotary table, the guide rail is connected with a guide rail sliding block, the optical transmitting and receiving device is arranged on the guide rail sliding block, the optical transmitting and receiving device is suspended right above the reflecting mirror, and the optical transmitting and receiving device is connected with the calculation unit.

As a further improvement of the present invention, the optical transmitting and receiving device includes a laser, a beam splitter and a plane detector, wherein the laser emits collimated laser, and then is projected onto the mirror through the beam splitter, the mirror reflects the laser onto the beam splitter, and the beam splitter projects the laser onto the plane detector.

As a further improvement of the invention, the planar detector is a two-dimensional photosensitive device array.

The invention also provides a measuring method of the calibration system, which adopts the calibration system to measure the included angle between the guide rail motion axis and the rotary table rotation axis.

As a further improvement of the invention, the method comprises the steps of:

s1, moving a guide rail sliding block to a first position, rotating a rotary table, and connecting detection points of a plane detector to obtain a first circle;

s2, moving the guide rail sliding block to a second position, rotating the rotary table, and connecting the detection points of the plane detector to obtain a second circle;

s3, calculating an included angle alpha between a guide rail motion shaft and a rotary table rotation shaft:

α＝αrctαn((l2-l1)/δZ)

wherein l1 is the radius of the first circle, l2 is the radius of the first circle, and δ Z is the distance between the first position and the second position.

As a further improvement of the invention, before the step S1, the step S0 is carried out, the turntable is rotated to enable the light spot to draw a circle on the reflector, and the position of the reflector is adjusted to enable the circle drawn by the light spot on the reflector to be as small as possible.

As a further improvement of the present invention, in step S2, the first circle and the second circle are placed under the same coordinate system.

As a further improvement of the invention, in step S1, the planar detector obtains a spatial position point t every time the planar detector receives a light spot, and obtains spatial position point sets t1, t2, 8230, tn when the rotary table rotates, and obtains a first circle when the spatial position point sets t1, t2, 8230, tn are drawn under a coordinate system; the second circle is generated in the same manner as the first circle.

The invention has the beneficial effects that:

1) The included angle data of the guide rail motion axis and the rotary table rotation axis can be accurately acquired, so that compensation can be performed in the system, the influence of the error is completely eliminated, and the measurement precision is improved;

2) Because the included angle between the motion axis of the guide rail and the rotation axis of the rotary table can be accurately acquired, the adjustment requirement of the parallelism can be properly reduced, great convenience is brought to actual production, and the efficiency is greatly improved.

Drawings

FIG. 1 is a schematic diagram of a prior art cylindrical coordinate measuring system.

FIG. 2 is a schematic diagram of a calibration system of the present invention.

FIG. 3 is a schematic diagram of an optical transmitter and receiver of a calibration system according to the present invention.

FIG. 4 is a schematic diagram of a circle obtained by the optical transmitter and receiver of the calibration system of the present invention.

Fig. 5 is a schematic diagram of a measurement method of a calibration system of the present invention.

Detailed Description

The invention is further described in the following description and embodiments with reference to the drawings.

As shown in fig. 2 to 5, a calibration system includes three parts, an optical transmitting and receiving device 3, a reflector 2 and a calculating unit 3, which cooperate to realize the collection of the included angle.

Based on the calibration system, the following measurement method of the calibration system is carried out to measure the included angle between the motion axis of the guide rail 5 and the rotation axis of the turntable 4:

the reflecting mirror 2 is arranged on the rotary table 4, the optical transmitting and receiving device 3 is arranged on the guide rail sliding block 6 through the cross beam 7, the guide rail sliding block 6 is arranged on the guide rail 5, the guide rail 5 is a Z-axis guide rail, the rotary table 4 is rotated, the light spot can draw a circle on the reflecting mirror 2, and the position of the reflecting mirror 2 is adjusted to ensure that the circle drawn by the light spot on the reflecting mirror 2 is as small as possible, so that the error caused by the flatness of the reflecting mirror 2 can be ignored. And respectively moving the guide rail sliding block 6 to two or more positions along the Z axis, rotating the rotary table 4 to obtain corresponding position information, and calculating to obtain an included angle according to the position information.

The optical transmitting and receiving device 3 mainly includes a laser, a beam splitter and a plane detector, wherein the laser 31 emits collimated laser, the collimated laser passes through the beam splitter 32 and is projected onto the reflecting mirror 2, the reflecting mirror 2 reflects the laser onto the beam splitter 32, and the beam splitter 32 projects light onto the plane detector 33. Since the flat panel detector 33 is a two-dimensional array of photosensitive devices, when it receives a light spot, it can obtain a spatial position information t with a radius l, see fig. 3. When the turntable is rotated, sets of spatial position points t1, t2, \8230;, tn are obtained, and drawing these sets of position points under a coordinate system will result in a circle, see fig. 4.

The data acquisition method comprises the following steps: moving the guide rail slide block 6 to the position 1, and rotating the rotary table 4 to obtain a circle 8 at the position 1; the guide slide 6 is then moved to position 2 and the turntable 4 is rotated to obtain the circle 9 at position 2, see fig. 5, and both are placed under the same coordinate.

The calculation method comprises the following steps: when the guide slide 6 is moved to position 1, the radius l1 of the circle 8 is determined, and when the guide slide 6 is moved δ Z to position 2, the radius l2 of the circle 9 is determined, the following are:

α＝αrctαn((l2-l1)/δZ)

wherein alpha is the included angle between the guide rail motion axis Z and the rotary table rotation axis theta. It should be noted that, when the Z-direction movement axis and the laser emitting direction are strictly parallel, the circles on the right in fig. 5 are concentric circles, and when the two are not parallel, the two circles are staggered (on the right in fig. 5), but this does not affect the calculation of the α angle, and because of this feature, the method is very easy to operate.

The rotary table can be rotated at different Z-direction positions (2 or more than 2 positions) to respectively collect space point sets to obtain a plurality of track circles.

The calibration system and the measurement method thereof provided by the invention have the following advantages:

2) The included angle between the motion axis of the guide rail and the rotation axis of the rotary table can be accurately acquired, so that the adjustment requirement of parallelism can be properly reduced, great convenience is brought to actual production, and the efficiency is greatly improved.

The calibration system and the measurement method of the calibration system provided by the invention can be used for the adjustment and compensation of various column coordinate instruments and processing equipment, and have stronger universality and larger market value.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A measuring method of a calibration system is characterized in that: the calibration system comprises a calculation unit, an optical transmitting and receiving device, a reflecting mirror, a rotary table and a guide rail, wherein the reflecting mirror is arranged at the center of the rotary table, the guide rail is connected with a guide rail sliding block, the optical transmitting and receiving device is arranged on the guide rail sliding block, the optical transmitting and receiving device is suspended right above the reflecting mirror, and the optical transmitting and receiving device is connected with the calculation unit;

the included angle between the guide rail motion shaft and the rotary table rotation shaft is measured by adopting the calibration system;

the method comprises the following steps:

s3, calculating an included angle a between a guide rail movement shaft and a rotary table rotation shaft:

a＝arctan((l2-l1)/δZ)

2. The measurement method of the calibration system according to claim 1, wherein: the optical transmitting and receiving device comprises a laser, a spectroscope and a plane detector, wherein the laser emits collimated laser, the collimated laser passes through the spectroscope and is projected onto the reflecting mirror, the reflecting mirror reflects the laser onto the spectroscope, and the spectroscope projects the laser onto the plane detector.

3. The measurement method of the calibration system according to claim 2, wherein: the plane detector is a two-dimensional photosensitive device array.

4. The measurement method of the calibration system according to claim 1, wherein: before the step S1, the step S0 is carried out, the rotary table is rotated to enable the light spots to draw a circle on the reflector, and the position of the reflector is adjusted to enable the circle drawn by the light spots on the reflector to be as small as possible.

5. The measurement method of the calibration system according to claim 1, wherein: in step S2, the first circle and the second circle are placed under the same coordinate system.

6. The measurement method of the calibration system according to claim 1, wherein: in step S1, the planar detector obtains a spatial position point t each time it receives a light spot, and obtains a set of spatial position points t1, t2, \8230;, tn, and obtains a first circle when the turntable rotates, and the set of spatial position points t1, t2, \8230;, tn is drawn in a coordinate system; the second circle is generated in the same manner as the first circle.