The Structual Design And Analysis Of The Scanning Motion Subsystem In 3DLIF System

3DLIF system is a kind of measurement system about 3D-scalar field of extensive water based on Laser-Induced Fluorescence technique,and is a new display mode of flow.This system can be used to reveal the inner structure of flow qualitatively,and measure concentration field,temperature field and velocity field quantitatively combined with image processing techniques.This paper summarized and analyzed the scanning methods of light sheet in 3DLIF technologies and instruments.According to the fundamental of 3DLIF technologies and the requirements on instruments,the scanning motion subsystem was studied and designed.A new kind of scanning method of light sheet was came up with;The scanning unit and the image acquiring unit moved synchronously to make the camera focus rapidly;A new kind of turn-back unit which moves at half velocity of the scanning unit was designed to compensate the optical path.The position of the light spot in the water channel can be kept constant by this design.Based on the design of the scanning motion subsystem,the optical configuration of the subsystem was designed and analyzed in detail.On the basic of the scanning methods raised previously,this paper designed the optical reflection part and the mechanical support part and analyzed structural stability.A type of U-linear motor table with single track and two move based on marble pedestal was designed.According to the design,this paper putted forward an adjustment method of the scanning motion subsystem with auto collimation theodolite and completed the adjustment of the scanning mechanism,compensation mechanism and linear motor table with accuracy to 8.9”.Based on the sweep-reflection mechanism and linear motor,several tests and experiments was designed,and the results of the tests shown that the displacement error caused by the reflection mirror would be less than 15?m;the position error of a single motor is less than 30?m,and the synchronous error of the double motors is less than 25?m.Finally,this paper established the error model of the scan compensation subsystem and simulated.The position error could be reduced to 0.244 mm and satisfied with the requirement of the error position less than 0.5mm.The physical design project and the adjustment project about scanning motion subsystem is effective and practicable.