Meeting Abstract
Bio-inspired “fish-like” robots come in a multitude of designs but are usually limited by slow speed, energy inefficiency, and high cost. Furthermore, few comprehensive comparative studies exist between such vehicles and their biological counterparts. We developed a thunniform robotic platform to study essential components of thunniform locomotion: kinematics, morphology, tail beat frequency, swimming speed, cost of transport, power consumption, Strouhal number, and thrust. The platform achieved a maximum tail beat frequency of 15 Hz which is comparable to tuna fish, and its maximum speed is 4.0 BL/s. High speed video captured the swimming mechanics of the platform from the ventral view at 1000 frames/s. Midline kinematics extracted from these videos were analyzed and compared against corresponding biological data, specifically the Atlantic mackerel fish (Scomber scombrus). We found that the effective angle of attack of the mackerel’s caudal fin is within the optimal range for dynamic stall except during the transition between tail beat directions. Conversely, the Tunabot’s rigid tail experiences effective angles of attack beyond deep dynamic stall for most of the tail beat period. This difference suggests the mackerel produces superior thrust by retaining the leading edge vortex, whereas the platform’s caudal fin quickly releases its leading edge vortex.
