CN-121973141-A - Triaxial leveling method based on center adjustment

CN121973141ACN 121973141 ACN121973141 ACN 121973141ACN-121973141-A

Abstract

The invention provides a triaxial leveling method based on center adjustment, which relates to the technical field of workpiece table leveling, and comprises the following steps: the method comprises the steps of obtaining an initial position of a workpiece table, establishing a space rectangular coordinate system, obtaining space parameters, obtaining heights of three connecting points of a motion axis and the workpiece table, calculating to obtain a theoretical inclination value of the workpiece table, calculating to obtain an inclination variation according to the theoretical inclination value and the real-time inclination value, calculating an axis variation according to the space parameters and the inclination variation, calculating a leveling height and a leveling absolute value, and controlling a motion axis motor to move at a low speed according to the leveling absolute value to drive the workpiece table so that the connecting points reach the leveling absolute position. The technical scheme provided by the invention eliminates the motion error caused by the problems of mechanical friction and the like, ensures the relative level of the workpiece table to the reference system, has high accuracy, has simple physical realization, short algorithm and convenient and quick operation, and enables the high stability and accuracy of the leveling of the workpiece table to be possible.

Inventors

LI YANLI
XIAO QIYUAN
CHEN LEI
Xu Peican

Assignees

中国科学院光电技术研究所

Dates

Publication Date: 20260505
Application Date: 20260130

Claims (10)

1. A triaxial leveling method based on center adjustment, characterized in that the method comprises the following steps: step S1, acquiring an initial position of a workpiece table, and controlling all motion axes to rise at a uniform speed at the same time so as to enable the whole workpiece table to rise to a safe distance relative to the initial position; s2, establishing a space rectangular coordinate system according to the motion axis of the workpiece table; s3, acquiring space parameters according to a connecting point of a motion axis and a workpiece table and a preset center reference point of the workpiece table; s4, measuring and obtaining a real-time inclination value of the workpiece table around an x axis and a real-time inclination value of the workpiece table around a y axis through an inclinometer; step S5, acquiring the heights of three connecting points of a motion shaft and a workpiece table according to motor feedback; S6, calculating a theoretical inclination value of the workpiece table around the x axis and a theoretical inclination value of the workpiece table around the y axis according to the heights of three connecting points of the motion axis and the workpiece table and the space parameters; S7, calculating to obtain an inclination variation according to the theoretical inclination value of the workpiece table around the x axis and the theoretical inclination value of the workpiece table around the y axis and the real-time inclination value of the workpiece table around the x axis and the real-time inclination value of the workpiece table around the y axis; S8, calculating to obtain an axis variation according to the space parameter and the inclination variation; Step S9, obtaining a leveling height according to the heights of three connecting points of the motion axis and the workpiece table, the space parameters and the axis variation amount; step S10, calculating a leveling absolute value according to the leveling height and the inclination change amount, and And S11, controlling the motion shaft motor to move at a low speed according to the leveling absolute value to drive the workpiece table so that the connecting point reaches the leveling absolute position.
2. The tri-axial leveling method based on center adjustment according to claim 1, wherein the step S2 comprises: The workpiece table is provided with three non-collinear motion shafts, namely a first motion shaft, a second motion shaft and a third motion shaft, wherein the axial direction of the motion shafts is perpendicular to an ideal horizontal plane and is respectively connected with three endpoints of the workpiece table; The projection of the connecting line of the second movement axis and the third movement axis and the two intersection points of the workpiece table plane on an ideal horizontal plane is a y axis; An axis which is vertical to an ideal horizontal plane, parallel to the axial directions of the first moving axis, the second moving axis and the third moving axis and passes through any point on the y axis is a z axis, wherein the z axis is positive in a vertical upward direction; the axis perpendicular to the yOz plane and orthogonal to the y axis and the z axis and crossing the intersection point of the yOz plane and the y axis is the x axis, so that the right hand rule is satisfied; wherein the origin in the established space rectangular coordinate system is located at a selected point on the y-axis.
3. The three-axis leveling method based on center adjustment according to claim 1, further comprising the steps of independently driving a motion axis by a motor and feeding back the height of the connection point between the motion axis and the workpiece table in real time, wherein the elevation of the three connection points is controlled respectively to adjust the pitching, the swaying and the overall height of the workpiece table.
4. The tri-axial leveling method based on center adjustment according to claim 2, wherein the step S3 comprises: Determining the gravity center of the workpiece table as a central reference point, wherein the coordinates of the central reference point are as follows ; The coordinates of the connection points of the first movement axis, the second movement axis, the third movement axis and the workpiece table are respectively 、、 And (C) sum Defining space parameters under the space rectangular coordinate system 、、、、、 The method comprises the following steps: 、、、、、。
5. The three-axis leveling method based on center adjustment according to claim 4, wherein the heights of the three connection points of the movement axis and the work table obtained in the step S5 are respectively 、、 The step S6 includes: Calculating a theoretical inclination value of the workpiece table around the x-axis in the space rectangular coordinate system The following are provided: ; in the space rectangular coordinate system, calculating a theoretical inclination value of the workpiece table around the y axis The following are provided: 。
6. The tri-axial leveling method based on center adjustment according to claim 5, wherein the step S7 includes: According to the formula Calculating to obtain the inclination variation of the workpiece table around the x-axis , wherein, For real-time tilt values of the workpiece table about the x-axis, and According to the formula Calculating to obtain the inclination variation of the workpiece table around the y axis , wherein, And (5) real-time inclination value of the workpiece table around the y axis.
7. The tri-axial leveling method based on center adjustment according to claim 6, wherein the step S8 includes: According to the formula Calculating to obtain the axis variation corresponding to the first motion axis ; According to the formula Calculating to obtain the axis variation corresponding to the second motion axis ; According to the formula Calculating to obtain the axis variation corresponding to the third motion axis ; Wherein the axis variation is the distance between the connecting points of the corresponding motion axes and the leveling height when the workpiece table reaches the leveling state The axis variation includes an axis variation corresponding to the first motion axis Corresponding to the second motion axis The amount of change in the axis corresponding to the third axis of motion 。
8. The tri-axial leveling method based on center adjustment according to claim 7, wherein the step S9 includes: calculating the center height according to the heights of three connecting points of the motion axis and the workpiece table and the space parameters The center height Calculated by the following formula: ; calculating the leveling height by the following formula : 。
9. The center adjustment based tri-axial leveling method of claim 8, further comprising: the three motion axes of the workpiece table are controlled to synchronously descend slowly along the negative direction until any one motion axis touches the initial position and then stops, and the height feedback values of the three motion axes during the stop are read and recorded as the initialization compensation quantity 、、 The initial compensation quantity of the motor feedback value serving as the connecting point of the motion axis and the workpiece table is used as the real height feedback of the connecting point.
10. The center-based tri-axis leveling method according to claim 8, wherein the step S9 further comprises: Three connection points for the motion axis and the workpiece table, which are known in space for x, y and z 、、 A plane formed according to two vectors in the plane 、 The cross product of (a) yields the components of the normal vector projection in the x, y, z axes: ; ; ; Calculation method vector modulo length ; Said space rectangular coordinate system , The projection of the straight lines connected with each other on the ideal plane is the y axis, then And has: ; ; ; Setting the safety upper limit of the inclination angle to be 3 degrees so as to reduce the sliding risk on engineering, and calculating , ; Calculation of ; Definition of the definition Is the rotation angle of the workpiece table around the y axis, Is the rotation angle of the workpiece table around the x axis; ; ; Establishing a plane equation according to the normal vector and the connection point: ; Assume that For a point in the plane, there are: ; According to , , , , , Carrying in to obtain: 。

Description

Triaxial leveling method based on center adjustment Technical Field The invention relates to the technical field of workpiece table leveling, in particular to a triaxial leveling method based on center adjustment. Background The work table is a mechanical plane laid out in a spatially multi-axis position in an automatically controlled industrial apparatus, and such a mechanical plane often requires a relatively level of precision and small errors to be maintained for an ideal plane of the reference (typically ground). After the relative level is realized by the leveling means, the processing and detection precision and stress uniformity of the object can be ensured, the accumulated error caused by physical factors such as motor movement, equipment abrasion and the like is reduced, and the stability and reliability of operation are improved. Therefore, the workpiece table leveling technology becomes an important tool for realizing the fields of objective lens detection, spin exposure, interference scanning and the like in the industrial field. The leveling process of the workpiece table is to perform microcosmic regulation and control on movement data of a motion shaft of the workpiece table, and the leveling process of a reference physical plane is realized by adjusting the spatial position of the shaft. Currently, no industry standard exists for leveling at fixed points in space, and the spatial layout of different workpiece tables is inconsistent. In the leveling process, precision errors are caused by the performance of a motor or the idle return of motion, so that the workpiece table is difficult to be absolutely horizontal to an ideal plane, and industrial environments requiring high precision such as object detection and image recognition are severely restricted. In most leveling devices at present, air floatation devices are often adopted to reduce friction pneumatically or utilize the center of gravity of a ball wrist for leveling. Although these methods have easy operation, the volume, mass and cost of the equipment itself are extremely large, and are disadvantageous in realizing automated control in the field of industrial equipment. The bulk and mass of most industrial equipment itself is already difficult to neglect, and if leveling equipment is used which is linearly related to the bulk mass of the industrial equipment, the use, maintenance and transportation of the equipment becomes extremely complicated. Disclosure of Invention The invention aims to provide a triaxial leveling method based on center adjustment, which is used for solving the problems of volume redundancy and weight redundancy caused by additionally adding a leveling system in the prior art. The invention provides a triaxial leveling method based on center adjustment, which comprises the following steps of S1, obtaining an initial position of a workpiece table, controlling all movement axes to rise at uniform speed at the same time, and enabling the whole workpiece table to rise to a safe distance relative to the initial position; the method comprises the steps of establishing a space rectangular coordinate system according to a moving axis of a workpiece table, establishing a space rectangular coordinate system according to the moving axis of the workpiece table, obtaining space parameters according to connecting points of the moving axis and the workpiece table and a preset center reference point of the workpiece table, obtaining real-time inclination values of the workpiece table around an x axis and real-time inclination values of the workpiece table around a y axis through measurement of an inclinometer, obtaining heights of three connecting points of the moving axis and the workpiece table according to feedback of a motor, obtaining theoretical inclination values of the workpiece table around the x axis and theoretical inclination values of the workpiece table around the y axis according to the heights of the three connecting points of the moving axis and the workpiece table and the space parameters, calculating to obtain theoretical inclination values of the workpiece table around the x axis and theoretical inclination values of the workpiece table around the y axis, obtaining inclination change amounts according to the theoretical inclination values of the workpiece table around the x axis and the real-time inclination values of the workpiece table around the y axis, obtaining an axis change amount according to the space parameters and the inclination change amounts, obtaining shaft change amounts according to the motor feedback, obtaining heights of the three connecting points of the moving axis and the workpiece table, obtaining absolute change amounts according to the three connecting points of the moving axis and the three connecting points of the workpiece table, obtaining absolute change amounts according to the absolute change values, and obtaining the absolute change values according to the absolute values, and