On-site accuracy evaluation of laser tracking attitude measurement system.

In this study, an on-site attitude accuracy evaluation method based on parallel mechanism model and indirect traceability from length to angle is proposed. Firstly, the mathematical model is established. Through orthogonal experimental design, quantitative analysis shows that the ranging accuracy and control layout have a significant impact on the accuracy of the evaluation system. On this basis, the layout of control field is optimized by genetic algorithm. Finally, the practicability of the evaluation method is verified by experiments. The results show that the yaw and pitch accuracy of the method are 0.008°and 0.007°respectively in the range of -25°to 25°within the working distance of 8 m. This method can accurately and effectively evaluate the attitude angle information of the measurement system and is adapted to various on-site environments. The research provides an innovative idea which can be used to ensure the strict requirements of attitude angle measurement in fields such as intelligent manufacturing and in situ processing.

Calibrating Laser Three-Dimensional Projection Systems Using Binocular Vision.

A laser three-dimensional (3D) projection system is an auxiliary system in intelligent manufacturing. It works with a positioning system in practical applications. This study proposes a calibration method for laser 3D projection systems based on binocular vision. The significance of the binocular vision positioning function for the calibration process was analyzed. Two calibration methods for laser 3D projection systems based on the binocular vision positioning function were proposed. One method involves simplified calculation models and another used data to solve the conversion relationship. The experimental calibration of the projection system was performed using data to directly solve the conversion relationship. The experiment demonstrated the simplicity of the proposed calibration method. The calculation time was less under the 3D laser projection system based on binocular vision. Moreover, the mean calibration error was 0.38 mm at a working distance of 1.8-2.2 m.

Research on Key Technologies for the Static Measurement of Railway Track Smoothness.

In this study, a static railway track smoothness detection system based on laser reference, which can measure various track smoothness parameters by using multiple sensors, is proposed. Furthermore, in order to improve the measurement accuracy and stability of the system, this paper also conducted three key analyses based on the static track measurement system. By using a liquid double-wedge automatic compensation device to compensate the horizontal angle of the beam, a mathematical model of liquid double-wedge automatic compensation was established. Then, by using an optical ring grating system to ring-grate and characterize the laser spot, the collimation efficiency of the system was improved when measuring at long distances. For the special ring grating spot image, an adaptive image processing algorithm was proposed, which can achieve sub-pixel-level positioning accuracy. This study also conducted a field measurement experiment, comparing the experimental data obtained via the static track measurement system with the results of existing track measurement products, and verifying that the static track measurement system has high measurement accuracy and stability.