Research On Technologies Of Oscillating Mirror Scanner For Imaging Ladar

The critical technology and related theory of oscillating mirror laser scanner are discussed in detail in this dissertation. The problem of existing rotating mirror scanner is analyzed in general, and an improved project of 2-D laser scanner is proposed for higher resolution in vertical direction.The improved laser scanner is composed of existing rotating mirror and adding oscillating mirror. According to the principle of improved scanner and the function of oscillating mirror, the performance specifications of oscillating mirror scanner are proposed.The mechanical design which is characteristic of flexure and voice coil actuators is discussed using integrated mechanical-control design method, after analyzing and comparing optional projects. The mechanical design of reflecting mirror is analyzed and determined with compromise between weight and stiffness. The mechanical stiffness of the flexure is discussed and determined for optimization of overall system performance and facility of controller. The flexure mechanical design and controller prototype are proposed.Experimental researches are implemented to examine the feasibility of scanner design. Virtual instruments based on LabVIEW and USB 6229 are developed for transfer function identification. The transfer function model is built according to the frequency characteristic and working mechanism of the control object. With comparing to commercial dynamic signal analyzer, the VIs have the same performance and lower cost. With the high accurate transfer function, cascade compensator is designed to eliminate the mechanic resonance of control object. The compensator is implemented on embedded computer system and closed-loop experiment is completed. Experiment result shows that with the compensator added to the forward path, the system closed bandwidth is expanded effectively to about 100Hz, exceeding mechanic resonance frequency. The feasibility of the design is proved by the experiment.