Two-Camera Imaging System for Kinematic Measurements

A high-speed imaging system has been devised as a noninvasive means of collecting data on the kinematics of working models of developmental underwater or aerial vehicles that would utilize flapping fins or flapping wings for propulsion. The system includes two high-speed digital electronic cameras aimed along orthogonal axes that acquire snapshots of a model simultaneously in rapid succession. The data from successive images are postprocessed to obtain three-dimensional coordinates of points of interest on the model as functions of time. In the case of a flapping appendage, the points of interest are tips on the appendage, and the temporal evolution of the tip coordinates through multiple flapping cycles is utilized, in conjunction with computational fluid dynamics and other analytical tools, in an iterative process of testing and design directed toward improving the swimming or flying performance of the model. The system can, of course, be used as a noninvasive means of kinematic testing of models other than those of vehicles utilizing flapping appendages.