Dynamic characteristic of a biomimetic underwater vehicle

For predicting the dynamic characteristics of a fishlike AUV testbed, which is under development at National Taiwan University, we developed a practical method to simulate the undulatory locomotion of a flexible slender body. When a flexible slender body, which is divided into a number of segments undulates, the wave passes from the nose to the tail. Reaction forces due to momentum change, friction, as well as cross flow drag acting on each segment are taken into account. Equations of motions described by the body-fixed coordinate are obtained by taking the summation of the longitudinal force, lateral force and yaw moment acting on all the segments. Equations of motions are solved step by step in time axis and the velocity is transferred to space-fixed coordinates for integrating the trajectory. In numerical simulation, a digital filtering technique is applied to avoid drifting in sway and yaw motions and the steady state solutions can be obtained. Based on the results of a series of simulation calculations, the dynamic characteristics of the BAUV testbed are shown and discussed in this paper.