The original planar mechanism achieved our goal of accurate bird wing motion, but we wished to add an additional second plane of motion in order to achieve more realistic wing tip movement similar to that of a bat.
This was the original intent of our project because we felt in would help introduce kinematic complexity and accuracy in our our mechanism. We wanted to build a robot that was fast, dynamic, and had the dexterity or a real bird. Taking the next step to creating a robot that moved in a three dimensional space seemed like a logic first step.