Calibration of the laser displacement sensor and integration of on-site scanned points

Abstract

On-site inspection with a laser displacement sensor installed on the spindle of a three-axis machine tool has found a wide range of applications in industrial processes. The calibration of the beam direction and the integration of the on-site scanned points are crucial for the measurement of free-form surfaces. This paper presents a method to calibrate the unit direction vector of the laser beam and integrate the on-site scanned points based on a standard ball. By scanning the fixed ball, a group of nonlinear equations is constructed. The nonlinear equations are solved by the Levenberg–Marquardt algorithm to get the unit direction vector of the laser beam and the center position of the standard ball. Then the coordinate transformation parameters between the world coordinate system and the sensor coordinate system are calculated. The scanned points from different coordinate systems are transformed into the world coordinate system by the coordinate transformation. The method simplifies the traditional calibration process and realizes the integration of the multi-angle scanned points on a three-axis machine tool. The feasibility and effectiveness of this method are verified through simulation and practical experiment. By comparing fitting value under different measuring conditions with the nominal, the measurement parameters including the incident angle and the scan depth are optimized. In the experiment, the measurement accuracy of this method reaches 0.02 mm.

Design of the Automated Calibration Process for an Experimental Laser Inspection Stand

“…This is due to the so-called measurement error, namely the eccentricity of the location of the rotating shaft that is sensed and the rotating table. Ideally, the axis of the shaft should be in line with the axis of the rotating table, which is not the case and manifests itself as the first harmonic component in the measurement: The most common solution for removing the first harmonic component from th measurements can be performed using the general discrete Fourier transform suitable fo the point cloud given in (9), where N declares the number of samples-in this case, 11,00 (according to Table 1), n means evaluation, k-frequency, and 𝑋(𝑘) mean 𝑘 frequency The graphical output of the Fourier transform is shown in Figure 8. In the upper part o the figure, the course of the sinusoidal character relation between the points according to time (Y axis) and the amplitude of the points (X axis) is displayed in blue.…”

“…A comparison of the real points and the calculated first harmonic component is shown in Figure 8 above (red sine wave). Although the Fourier transform is a universal and reliable method, the output from The most common solution for removing the first harmonic component from the measurements can be performed using the general discrete Fourier transform suitable for the point cloud given in (9), where N declares the number of samples-in this case, 11,000 (according to Table 1), n means evaluation, k-frequency, and X(k) mean k th frequency. The graphical output of the Fourier transform is shown in Figure 8.…”

“…Sensors 2022, 22, x FOR PEER REVIEW 8 of 1 The most common solution for removing the first harmonic component from th measurements can be performed using the general discrete Fourier transform suitable fo the point cloud given in (9), where N declares the number of samples-in this case, 11,00 (according to Table 1), n means evaluation, k-frequency, and 𝑋(𝑘) mean 𝑘 frequency The graphical output of the Fourier transform is shown in Figure 8. In the upper part o the figure, the course of the sinusoidal character relation between the points according t time (Y axis) and the amplitude of the points (X axis) is displayed in blue.…”

“…The work compares values from simulation and calibrated and non-calibrated measurements, respectively. The measuring system with included calibration is the principal requirement for the good functioning of measuring machines [ 9 ].…”

Orthogonality Measurement of Three-Axis Motion Trajectories for Micromanipulation Robot Systems

“…In recent years, laser displacement sensors based on the principle of triangulation have developed rapidly, with the emergence of point sensors, stripe-structured light sensors, etc., which can detect the position of a single point or multiple simultaneously and are being increasingly widely used for many tasks such as shape reconstruction, geometric dimension measurement, distance measurement, etc. [ 28 , 29 , 30 , 31 ]. The design of the laser displacement sensor is modularized and compact.…”