A Numerical Algorithm to Reconstruct the Missing Points from the Membrane Wings of a Bat via the Computerized Motion Capture System

Abstract

The bat is an efficient flyer with flapping membrane wings but the measurement of aerodynamic forces is the major challenge. The motion of the bat’s wing is very complex which comprises translation as well as rotation. During the bat’s flight, the wing membrane will deform in the downstroke and upstroke process of wings. The investigation of the detailed kinematics of short-nosed fruit bat (Cynopterus sphinx) was conducted. We performed high-speed recordings of the kinematics to obtain 3D reconstructions of membrane wing movements. Living bats were used for performing the experiments. We used the motion capture system, OptiTrack, to measure the data set on the flapping membrane wings of the bat and finally rebuild the bat’s flight in the form of soft wings through this experiment. However, due to the complex kinematics of the bat’s wing, there are some periods when many points on the wing cannot be tracked by the motion capture system as the wing flaps. To rebuild the wing profile, a detailed analysis of every point is required. Therefore, this paper proposes numerical algorithms and MATLAB programs to recover the missing data from the wing during the flight of a bat. It is the purpose to find efficient calculation and analysis procedures and to provide ideas and techniques for the analysis of all marked points on the membrane wings of the bat.