Error calibration of five-axis machine tools by on-machine measurement system using a laser displacement sensor

The R-test is a new instrument to measure three-dimensional displacement of a precision sphere attached to a spindle relative to a work table by using three displacement sensors. Its application to error calibration for five-axis machine tools has been studied in both academia and industry. For the simplicity in calculating the sphere center displacement, all conventional R-test devices use contact-type displacement sensors with a flat-ended probe. Conventional contact-type R-test may be potentially subject to the influence of the friction or the dynamics of supporting spring in displacement sensors particularly in dynamic measurement. This paper proposes a non-contact R-test with laser displacement sensors. A new algorithm was proposed to estimate the three-dimensional displacement of sphere center by using laser displacement sensors, It compensates the measurement uncertainty caused by the inclination of the target surface. Experimental case studies are presented to evaluate its measurement performance by comparing with the conventional contact-type R-test device.

Download Full-text

Base Detection Research of Drilling Robot System by Using Visual Inspection

Journal of Robotics ◽

10.1155/2018/8767531 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Zhanxi Wang ◽

Jing Bai ◽

Xiaoyu Zhang ◽

Xiansheng Qin ◽

Xiaoqun Tan ◽

...

Keyword(s):

Coordinate System ◽

Light Source ◽

Measurement System ◽

Visual Inspection ◽

Displacement Sensor ◽

Hole Drilling ◽

Laser Displacement Sensor ◽

Robot System ◽

Visual Measurement ◽

Drilling System

This paper expounds the principle and method of calibration and base detection by using the visual measurement system for detection and correction of installation error between workpiece and the robot drilling system. This includes the use of Cognex Insight 5403 high precision industrial camera, a light source, and the KEYENCE coaxial IL-300 laser displacement sensor. The three-base holes method and two-base holes method are proposed to analyze the transfer relation between the basic coordinate system of the actual hole drilling robot and the basic coordinate system of the theoretical hole drilling robot. The corresponding vision coordinates calibration and the base detection experiments are examined and the data indicate that the result of base detection is close to the correct value.

Download Full-text

Error Calibration for Five-Axis Machine Tools by On-the-Machine Measurement Using a Touch-Trigger Probe

International Journal of Automation Technology ◽

10.20965/ijat.2014.p0020 ◽

2014 ◽

Vol 8 (1) ◽

pp. 20-27 ◽

Cited By ~ 26

Author(s):

Soichi Ibaraki ◽

◽

Yusuke Ota

Keyword(s):

Machine Tool ◽

Test Piece ◽

Machine Tools ◽

Experimental Demonstration ◽

Arbitrary Geometry ◽

Rotary Axes ◽

Ball Bar ◽

Touch Trigger Probe ◽

Error Calibration ◽

Five Axis

This paper presents a scheme to calibrate the error map of the rotary axes of a five-axis machine tool. This is done by means of on-the-machine measurement of a test piece using a contact-type touch-trigger probe. The present probing-based approach is more suitable for efficient and automated “self-calibration,” than conventional calibration schemes, such as ball bar tests or R-test. It is thus advantageous in the application to periodic checking of the error map, or periodic updating of its numerical compensation. In the present approach, a test piece of arbitrary geometry, e.g. a raw unmachined workpiece, can be used as the probing target. An experimental demonstration is presented.

Download Full-text

R-Test Analysis Software for Error Calibration of Five-Axis Machine Tools – Application to a Five-Axis Machine Tool with Two Rotary Axes on the Tool Side –

International Journal of Automation Technology ◽

10.20965/ijat.2015.p0387 ◽

2015 ◽

Vol 9 (4) ◽

pp. 387-395 ◽

Cited By ~ 14

Author(s):

Soichi Ibaraki ◽

◽

Yu Nagai ◽

Hisashi Otsubo ◽

Yasutaka Sakai ◽

...

Keyword(s):

Machine Tool ◽

Machine Tools ◽

Three Dimensional ◽

Geometric Error ◽

Test Analysis ◽

Rotary Axes ◽

Rotary Axis ◽

Displacement Sensors ◽

Error Calibration ◽

Five Axis

The R-test measures the three-dimensional displacement of a precision sphere, attached to a machine spindle, by using three displacement sensors fixed to the machine’s table. Its application to error calibration for five-axis machine tools has long been studied. This paper presents software for analyzing the measured R-test trajectories for error diagnosis and numerical compensation for rotary axis location errors and error motions. The developed software first graphically presents the measured R-test trajectories to help a user intuitively understand error motions of the rotary axes. It also numerically parameterizes the rotary axis geometric error parameters, and then generates a compensation table that can be implemented in some latest-generation commercial CNC systems. An actual demonstration of its application to a five-axis machine tool with a universal head (two rotary axes on the spindle side) is presented.

Download Full-text