Probe position linearization calibration method for on-machine laser measurement

Abstract

The invention discloses a probe position linearization calibration method for on-machine laser measurement. The method comprises steps that, a measurement model of a laser probe moving along with a machine tool is established, a machine tool motion program is generated in an offline mode, the laser probe is driven by the machine tool to carry out multi-angle scanning of a standard ball for ball center fitting, a linear equation group of a standard ball center under multiple machine tool rotation angles and a probe mounting position relationship is acquired, probe mounting position parameters can be acquired through solving the equation group, that a calibration problem is expressed as a nonlinear optimization problem with constraint is not required, and problems of massive calculation and instability existing in nonlinear optimization solution can be avoided.

Description

technical field [0001] The invention belongs to the technical field of on-machine laser measurement, and more particularly relates to a method for calibrating and error compensation of a measuring head installation for on-machine laser measurement. Background technique [0002] The non-contact measurement method represented by laser measurement has the advantages of fast speed, no wear, and no need for probe radius compensation. It can greatly improve the efficiency of measurement while meeting the measurement accuracy, and can obtain more detailed surface information. On-machine measurement can detect problems in manufacturing engineering in time, and then introduce measures such as error compensation to correct these problems in time. An important form of on-machine measurement is to clamp a one-dimensional distance-measuring laser probe at the end of the spindle of a CNC machine tool, drive the laser line from the laser probe to scan the surface of the workpiece through ...

AI Technical Summary

Problems solved by technology

[0003] The laser probe is installed on the moving spindle of the machine tool through a mechanical clamping mechanism, but the installation posture of the laser probe is difficult to adjust precisely

In order to compensate the measurement error caused by the installation position and deflection angle, the traditional method is to use the position sensitive detector and the specially designed fixture mechanism to manually adjust the beam axis of the laser probe so that it passes through the center of rotation of the rotary body of the probe, but manually The operation of adjusting the beam direction is very inconvenient, and the accuracy is greatly affected by human factors

Later, a V-shaped block was used to calibrate the beam direction of the laser probe, but this method can only solve the installation attitude of the probe, and cannot determine the installation position

In order to obtain the zero position of the beam of the laser probe, a standard ball is used to calibrate the installation position of the probe, and the V-shaped block is used to calibrate the beam direction of the laser probe. However, because two calibration objects are used in the entire calibration, the calibration process is relatively cumbersome

In order to further improve the calibration technology, a method to simultaneously calibrate the beam direction and beam zero position of the laser probe with a single standard sphere has emerged. The installation attitude is obtained by establishing the positional relationship between the probe and the standard sphere in multiple directions, but the calibration problem Expressed as a nonlinear optimization problem with constraints, the unconstrained optimization objective function of the parameters to be calibrated is established through the penalty function, and then the genetic algorithm is used for nonlinear search and optimization. Stability issue

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