Modelling of robotic manta ray propelled by servo-actuated pectoral fins

Abstract

In this research, a two-dimensional (2D) manoeuvrable bio-mimic robotic manta ray propelled by two servo-actuated pectoral fins is developed. To fulfil the driving requirements for propelling the robotic manta ray, a single fin ray is used for each pectoral fin. Servos are used to drive the fin rays and generate required deformations on the pectoral fin. A computational fluid dynamic (CFD) model, which captures the thrust forces generated by the three-dimensional kinematic motion, is developed. A 2D dynamic model, which incorporates the CFDs of pectoral fin and the body dynamics of the robot, is then developed. Experimental study revealed that the forward velocity was in a nearly linear relation with the flapping frequency, while the angular velocity depends on the differences between the flapping frequencies of two pectoral fins. A forward speed of 0.53 body length per second and angular velocity of nearly 1.25 rad/s were achieved by the robot, and the non-linear dynamic model was validated by experiments.