Design and Experimental Parameteric Study of a Fish Robot Actuated by Piezoelectric Actuators

This paper presents the design and experimental parametric study of a biomimetic fish robot actuated by two lightweight piezo-composite actuators. The biomimetic aspects in this work are the mimicking of an oscillating tail-beat motion and the shape of an artificial caudal fin. Artificial caudal fins that resemble the fins of fish propelled by the body-and-caudal fin mode are fabricated for a parametric study of the way caudal fin characteristics affect the production of thrust at an operating frequency range. The observed caudal fin characteristics are the shape, area, and aspect ratio. A caudal fin with a high aspect ratio contributes to the high swimming speed of the present fish platform. A fish robot propelled by an artificial caudal fin shaped like the fin of a thunniform fish, which has a relatively high aspect ratio, produces a swimming speed as high as 2.364 cm/s for a 300 V pp input voltage excited at 0.9Hz. The thrust performance of the biomimetic fish robot is examined in terms of the Strouhal number, the Froude number, the Reynolds number, and power consumption.