Design and Hydrodynamic Simulation of a Novel Manta Ray Robot with Flexible Pectoral Fins

The manta ray with large and flat pectoral fins is a typical median-paired fin mode propulsion fish with high stability, manoeuvrability, and efficiency. In this paper, a novel manta ray inspired robot with flexible pectoral fins is developed. The pectoral fins are directly and independently driven by the waterproof servos, which are connected to the rigid leading edge and drives the entire flexible PVC fin to oscillate in order to maintain amplitude, frequency, and phase stability. The segmented flexible thin plate models to replace continuous deformation of the pectoral fins are employed. Fluid simulations and vortex structure analyses were carried out via XFlow based on lattice Boltzmann method. Subsequently, a detailed analysis of the hydrodynamic simulation results are conducted. The results indicated that the robot exhibited hydrody-namic characteristics similar to the natural manta rays, with vortices attached to the leading and trailing edges of the fins during flapping. The chordwise flexibility had a significant impact on propulsive force generation, offering a theoretical foundation for optimizing propulsion structures of biomimetic underwater robot.