Beam direction vector and zero point position on-line calibration method for point laser sensor

Abstract

The invention provides a beam direction vector and zero point position on-line calibration method for a point laser sensor. The point laser sensor is arranged on the Z-axis of a five-axis three-coordinate measuring machine. A point laser sensor measurement path is set according to the machine tool structure of a three-dimensional machine tool to ensure that measurement light points always fall ona calibration plane to perform movement and data acquisition. Laser emission point coordinates, beam vectors and measured point coordinates under a measurement coordinate system are converted to a workpiece coordinate system through the space motion transformation matrix of the five-axis three-coordinate measuring machine. Finally, a linear indeterminate equation set is established, and a least square method is used to calculate the equation set to acquire the calibration result.

Description

technical field [0001] The invention relates to a technique in the field of measurement, in particular to an online calibration method for a beam direction vector and a zero point position of a point laser sensor. Background technique [0002] The measurement principle of the existing non-contact three-coordinate measuring machine is mainly to subtract the measurement data of the point laser sensor from z in the coordinate value (x, y, z) of the three-coordinate measuring machine, that is, the distance between the three-coordinate measuring machine and the workpiece to be measured The vertical distance L between them is used to obtain the coordinates (x, y, z-L) of the measured point on the surface of the workpiece. In the actual measurement process, due to the lack of installation reference, there are installation errors, there is an angle deviation between the laser beam of the point laser sensor and the vertical direction, and there is an inherent deviation between the ze...

AI Technical Summary

Problems solved by technology

[0004] The existing calibration method includes using a special plane calibration block with a known angle, using the angle between the beam of the point laser sensor and the normal vector of the plane as a known geometric relationship, and solving the beam direction vector; but this method can only Solve the beam vector of the point laser sensor, the zero point position of the beam cannot be solved, and the production accuracy of the plane calibration block is required to be high

The other type is to use the calibration sphere as the measurement reference, and determine the direction vector and zero point position of the laser beam by fitting the position of the center of the sphere and the radius of the sphere, but this method constructs a system of equations that is hyperstatically determined nonlinear , needs to use the initial value to solve, and the operability is poor in practical engineering applications

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