This work explores an alternative 3D geometry measurement method for non-cooperative spacecraft guiding navigation and proximity operations. From one snapshot of an unfocused light-field camera, the 3D point cloud of a non-cooperative spacecraft can be calculated from sub-aperture images with the epipolar plane image (EPI) based light-field rendering algorithm. A Chang'e−3 model (7.2 cm×5.6 cm×7.0 cm) is tested to validate the proposed technique. Three measurement distances (1.0 m, 1.2 m, 1.5 m) are considered to simulate different approaching stages. Measuring errors are quantified by comparing the light-field camera data with a high precision commercial laser scanner. The mean error distance for the three cases are 0.837 mm, 0.743 mm, and 0.973 mm respectively, indicating that the method can well reconstruct 3D geometry of a non-cooperative spacecraft with a densely distributed 3D point cloud and is thus promising in space-related missions.

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In this paper, three-dimensional wind-induced vibration control is investigated by using multiple tuned mass dampers (MTMD). A 20-story steel frame is take as a numerical example to compare the two control effects by using MTMD and TMD (tuned mass damper), in which the same control masses are set on the top floor respectively. The parameters and locations of the damper devices could be chosen optimally based on energy balance theory and genetic algorithm. Numerical results show that the total damp value and the total structural dissipative energy of MTMD is lower than TMD while the total mass are the same. Meanwhile, MTMD also shows a better performance on reducing the along wind displacement and torsion response of the structure than that of TMD.