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 0.9 Hz. 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.