Design, modeling, and experimental validation of a concave‐shape pectoral fin of labriform‐mode swimming robot

Abstract

The pectoral fin shape, size, and speed are the three main parameters for the proposed design. The influence of the geometrical shape of pectoral fin in labriform‐mode swimming mechanism is evaluated with the aid of computational fluid dynamics (CFD) method, which could be considered as a first step before building the complete robot prototype. The simulated results obtained are then validated experimentally. Two concave‐shape fins were designed with high precision, and each one of them is attached to a servomotor arm, which is, in turn, connected to a servomotor that is sliding on a pair of parallel shafts fixed at the center of a pool. The mathematical model of the proposed design is derived and then simulated by SolidWorks software. A different number of fin oscillating angles are tested with different power‐to‐recovery ratios. The generated thrust and drag force components under different working conditions are investigated, and hence, the drag coefficient is obtained experimentally. Body velocity and motor torque are calculated and compared with theoretical analysis. The results indicate that for each angle of rotation, there exists an optimal ratio that produces a maximum thrust during power stroke and maintains a minimum drag during recovery stroke.

Keywords

• computational fluid dynamics
• labriform mode
• pectoral fin
• power‐to‐recovery ratios
• swimming robot