Research On Structure Optimization Of Mobile Platform Borne Optical System For Visual Axis Stabilization

It is critical to describe the light beam propagation in the misaligned optical systemdue to mechanical vibration which mounted on mobile platform, and how to diminishoptical jitter is another problem. This paper deduced a simulation model of light beampropagation in the misaligned optical system by the means of ray tracing method whichwas based on coordinate transformation and reflection law, also a visual axis jittermodel was derived from the simulation model to provide the specific visual axis jitterangles after beam reflected by every mirror, this is a advantage to evaluate and diminishthe optical jitter in misaligned optical system.The study on structure optimization of optical system to diminish jitter is seldominvestigated by now. It is hard to formulate equation between the structure dimension,shape, topology and optical jitter, it seems that the current structure optimizationmethod is difficult to optimize the structure model, the available solution is to take theglobal structure topology into account to modify the model. This paper constructed astructure model of a theodolite by pro/e which was then imported to MSC.Patran_Nastran to perform a normal mode analysis, primarily the influencing mirrors to theoptical system was found by observing the mode shape. Then the finite element modelwas submitted to Nastran to perform transient response after applied sine vibration inthe xyz direction respectively and simultaneously so as to obtain the displacement ofkey points of mirrors, then the displacement was used by the visual axis jitter modelprogram to compute the jitter angles. The influencing mirrors were obtained, andcorresponding part structure was modified. Finally the optimized model was analyzedby the same procedure, results showed that the visual jitter diminished dramaticallywhich indicated the optimization to the theodolite was feasible.