Design Consideration of Bio-Inspired Contractible Water-Jet Propulsor for Mini Autonomous Underwater Robot

The main aim of this paper is to discuss the general design considerations for contractible water-jet propulsion system for mini underwater robot locomotion. The motivation of this paper is the problems that occurred to the motorized turbine blade propeller for a lower than centimeter scale underwater robot. Contractile water-jet propulsion mechanism is proposed to counter the turbine blade problem. hi this research, active materials had been proposed as the actuator for the contractile function. The integration of active material structure and passive structure caused significant consequence on the kinematic and dynamic of the robot. This including the dimension variation, stress distribution as well as contraction force which affects the hydrodynamic efficiency of the propulsion. Several essential design considerations were highlighted and discussed.