Method for the rapid detection of the linear axis angular error of an NC machine tool

Patent metadata

Field	Value
Publication number	US-10900779-B2
Application number	US-201816462238-A
Country	US
Kind code	B2
Filing date	Jan 23, 2018
Priority date	Jan 23, 2018
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A method for the rapid detection of the linear axis angular error of an NC machine tool, belongs to the technical field of NC machine tool testing. Firstly, the measuring device is mounted on the linear axis. Then, the linear axis moves at three different speeds at a constant speed, and the upper measurement system automatically performs multi-channel acquisition and storage of the motion measurement's point measurement data. Then, based on the same geometric error signal, it is decomposed into the different frequency components, and the measurement angle error is filtered at the different speeds. Finally, the measurement angle errors at the three speeds after filtering are superimposed to complete the rapid measurement of the linear axis angular error of the machine tool. The measurement efficiency is high and data processing capability is strong.

First claim

The invention claimed is:

1. A method for the rapid detection of the linear axis angular error of an NC machine tool, using gyroscopes and accelerometers to measure the deflection angle of the linear axis' uniform motion, and then calculate the pitch angle error, yaw angle error and roll angle error of the linear axis; firstly, the measuring device is mounted on the linear axis, and the initial angular error generated by the installation is determined by the accelerometers; then, the linear axis moves at three different speeds at a constant speed, and the data acquisition card automatically performs multi-channel acquisition and storage of the motion measurement's point measurement data; the Kalman filter principle is used to combine the accelerometer and gyroscope measurement angle information to obtain the angular error measured at the three speeds; then, based on the same geometric error signal, it is decomposed into the different frequency components, and the measurement angle error is filtered at the different speeds; finally, the measurement angle errors at the three speeds after filtering are superimposed to complete the rapid measurement of the linear axis angular error of the machine tool;
wherein the specific steps are as follows:
the first step is to assemble a rapid detection device for the linear axis angular error of NC machine tools;
a three-axis accelerometer is used, consisting of three single-axis accelerometers: 1 # single-axis accelerometer, 2 # single-axis accelerometer, and 3 # single-axis accelerometer; three gyroscopes are used to constitute a three-axis gyroscope: 4 # single-axis gyroscope, 5 # single-axis gyroscope, and 6 # single-axis gyroscope; then ensure that the measurement direction of 1 # single-axis accelerometer is the I direction; 2 # single-axis accelerometer measurement direction is the n direction; 3 # single-axis accelerometer measurement direction is the t direction; ensure that the 4 # single-axis gyroscope- 4 measures the rotation angle around the n direction's coordinate axis, the starting edge of the angle is the I coordinate axis, and clockwise rotation is positive; ensure that 5 # single-axis gyroscope measures the rotation angle around the t direction coordinate axis, the starting edge of the angle is the I coordinate axis, and counterclockwise rotation is positive; ensure that 6 # single-axis gyroscope measures the rotation angle around the I direction coordinate axis, the starting edge of the angle is the t coordinate axis, and clockwise rotation is positive; ensure that the three single-axis accelerometers and the three single-axis gyroscopes are fixed in detection box using nuts; detection box is then fixed on the linear shaft using the side flanges, and the clamping device of the linear axis of the numerical control machine tool is then completed;
the second step is the measurement the installation error of the measuring device;
first, control the linear axis I of the NC machine and move it to either end of its track; then, the data acquisition system of the upper computer stores the measurement data of each 1 # single-axis accelerometer, 2 # single-axis accelerometer and 3 # single-axis accelerometer which are a C0 1 , a C0 2 , a C0 3 respectively, and the pitch angle error α c and the roll angle error γ c of the measuring device are then obtained from equation (1):

{

α
c

=

arcsin
⁡

(

-

a

C
⁢

⁢
0

1

g

)

γ
c

=

arcsin
⁡

(

a

C
⁢

⁢
0

2

g
×

cos
⁡

(

α
c

)

)

(
1
)

where g is the acceleration due to gravity of the measurement position; then adjust the flange nut of the test box until the pitch angle error α c and the roll angle error γ c are within 0.1°;
the third step is the measurement of the linear axis angular error of the NC machine tool;
first, set val(val=max, mid, min) as the measuring speed of the measuring device; the three measuring speeds are high speed, medium speed and low speed; then, the measuring device is orientated in the I direction at high speed, medium speed and low speed from one side to the other of the linear axis; at the same time, the data acquisition system of the upper computer stores the coordinates of each measuring point and outputs the digital signal data at a high frequency; wherein the moving speed is calculated from equation (2):

Assignees

• Univ Dalian Tech

Inventors

• Wang Yongqing
• Liu Kuo
• Wu Jiakun
• Liu Haibo
• Liu Zhisong
• Liu Haining

Classifications

• G01B21/24 Primary

  for testing alignment of axes · CPC title

• G01M13/02

  Gearings; Transmission mechanisms · CPC title

• G01B11/27

  for testing the alignment of axes {(means for centering or aligning a light guide within a ferrule G02B6/3834)} · CPC title