Uncertainty Evaluation And Accuracy Analysis Of Laser Displacement Sensor In Measuring Curved Surface

Based on the point laser triangle principle, non-contact measurement method has advantages of simple structure, high measurement efficiency, zero measuring force, good real-time performance, etc.; therefore, it has been widely used in the rapid measurement of complex three-dimensional curved surface and reverse engineering. However, the measurement accuracy of this method is vulnerable to many factors, such as the nonlinear error of the system itself, the physical characteristics of the measured surface, the surrounding environment, especially the tilt angle of the measured surface. The main factors influencing the accuracy of laser displacement sensor during curved surface measurement process are researched in this thesis; each factor’s impact rule is analyzed from theory to experiment, fuzzy uncertainty theory was carried out to obtain a scientific basis for the reliability of measurement results.As for the effect of factors like the nonlinear performance of the sensor, the color and the material of the measured surface, corresponding solutions on the measurement accuracy are given.The normal direction of the measured surface is required to be consistent with the emission beam direction, and the error caused by tilt of the measured surface is called tilt angle error. As for the inevitable tilt angle errors in surface measurement process, a complete set of tilt angle error detection system is designed; meanwhile, the tilt error calibration curve of the laser sensor under different angle and displacement is attained.To obtain a scientific basis for the reliability of measurement results during the actual three-dimensional surface measurement of large-scale rocket nozzle, fuzzy evaluation of expanded uncertainty of the measured data on the actual profile of rocket nozzle is carried out utilizing fuzzy uncertainty theory.The research is of some reference value for the expansion of application scope of the laser triangle sensor and the improvement of the measurement accuracy.