Design and Analysis of a Shark Fin Inspired Pneumatic Actuator for Underwater Robots

Soft robots present themselves with outstanding flexibility, safety and environmental adaptability, which have been highly adopted in medical, bioengineering and special rescue, etc. Inspired by shark fins, this paper proposes the design and analysis of a pneumatic actuator for underwater robots. The actuator is composed of four movable modules including three origami structures and a fish-fin body. It can achieve shark-fin-like movement such as waving and turning by cooperating each module. Particularly, bending deformation and axial movement are evaluated via finite element analysis. The motion-matrix of the actuator is established and the modal control strategy is implemented to achieve a multi degree of freedom locomotion. Simulation studies indicate that it is promising to apply this actuator on an underwater robot to provide momentum for moving, steering, balancing and reversing as flexible and nimble as fish fins.