Performance Assessment and Actuator Design of a Flexible Tail Propulsor in an Artificial Alligator

The overall objective of this research is to develop analysis tools for determining actuator requirements and viable actuator technology for design of a flexible tail propulsor in an artificial alligator. A simple hydrodynamic model that includes both reactive and resistive forces along the tail is proposed and the calculated mean thrust agrees well with conventional estimates of drag. Using the hydrodynamic model forces as an input, studies are performed for a 1.5 m alligator having 5 antagonistic pairs of actuators distributed along the length of the tail. As a result of the large amplitude of the tail motion, large actuator forces and strains are required for an alligator swimming at speeds 0.3 to 1.8 body lengths/s. Several smart materials are considered for the actuation system, and preliminary analysis results indicate that the acrylic electroactive polymer and the flexible matrix composite actuators are potential artificial muscle technologies for the system.