During the summer of 2011, I worked as a researcher in Dr. Seelecke’s Multifunctional Materials Systems Lab at the Universität des Saarlandes in Saarbrücken, Germany. My work focused on the use of Shape Memory Alloy (SMA) wires to mimic the function of biological muscles. First, a kinematic model of the bat motion is developed in order to determine the desired joint movements needed for flapping flight. Then, a physical prototype is build that uses the contraction of SMA wires to control these movements.
In order to provide a realistic flapping motion, a simplified model of the bat wing is developed and tuned to match data collected from actual bats. A kinematic model shown to right, labels key components of the bat anatomy. For this model, I have included three degrees of freedom (DOF). The should, elbow and wrist joint are each allowed to rotate along a fixes axis. A sinusoidal function is applied to each joint, with amplitude, phase and frequency chosen individually to approximate the motion of a bat wing during horizontal flight.
The figure shown below shows the resulting trajectories. Black lines represent the wrist and wingtip trajectories from the kinematic model. The red trajectories represent data collected from actual bats.