Research On The Optimization Of Oil Film Thickness Measurement Sensor Using Laser Triangulation

The accurate detection of oil slick thickness is of great significance for environmental protection and warning of oil spill. According to the technical requirements, the research on the optimization of measuring sensor is completed based on the vertical differential laser trigonometry proposed by our group. The optical structure is designed and the method for compensating the error caused by the refractive index is studied. The main work is as follow:1. The measuring principle of oil film thickness using laser triangulation is introduced, and the measuring equation is derived in two kinds of medium. The modes of vertical and inclined receiving are compared based on the vertical differential laser trigonometry.2. According to the technical specifications, the optical structure of sensor is designed based on the technology parameters. The light path structure complies with the Scheimpflug conditions. Accordingly, the mechanical drawings of optical system is drawn and the gage block fixture is designed.3. The system based on the designed parameter is built to test the sensor and the software for acquiring the thickness data is optimized. System calibration and experiment of thickness measurement are conducted. Experimental results acquired in the water whose the refractive index is 1.3332 show that the maximum deviation between the nominal and measured value is less than 0.025 mm, and the relative error is less than 1.1%.4. The adversely effect of the seawater refractive index on the precision of thickness measurement is analyzed. And the relationship between the change of refractive index and error is studied. Accordingly, a method based on two-dimensional curved surface fitting is proposed to compensate the error. The verify experiment is completed.