OPTICAL PROCESSING FOR STRUCTURAL CONTROL OF LARGE SPACECRAFT

THE PROPOSED INNOVATION EXPLOITS THE USE OF NONLINEAR OPTICAL AND PHOTONIC DEVICES TO PERFORM SENSING, COMPUTING AND ADAPTIVE CONTROL OF VERY LARGE, FLEXIBLE SPACECRAFT SUBJECT TO INDUCED STRUCTURAL DYNAMICS. SPECIFICALLY, TECHNIQUES AND STRATEGIES WOULD BE DEVELOPED TO EXPLOIT THE MASSIVELY PARALLEL SENSING AND PROCESSING POTENTIAL OF PHOTOREFRACTIVE MATERIALS. TWO UNIQUE INNOVATIONS PROPOSED HERE ARE THE USE OF AN OPTICAL NOVELTY FILTER AND OPTICAL ASSOCIATIVE MEMORY TO BOTH DISCRIMINATE AND RESOLVE THE DYNAMIC MODES OF THE SPACECRAFT. THE OPTICAL NOVELTY FILTERCAN PERFORM TIME DIFFERENTIATION OF COHERENT OPTICAL IMAGES. THE TIME CONSTANT WOULD BE VARIED TO DISCRIMINATE BETWEEN STATIC AND DYNAMIC CONDITIONS OF THE STRUCTURE. THEASSOCIATIVE MEMORY CAN RECORD AND RETRIEVE A LARGE NUMBER OFCOHERENT IMAGES WHICH WOULD REPRESENT THE DYNAMIC MODE SHAPES OF THE STRUCTURE. CONTROL SIGNALS DERIVED FROM AN IMAGE RECOGNITION PROCESS WOULD THEN BE USED TO DRIVE ACTUATORS TO STABILIZE THE STRUCTURE.