Research On Hydrodynamic Performance Of Fishlike Robot Undergoing Steady State Swimming

In recent years, with the scarcity of land resources, people started to pay attention of marine resources. It caused the development of marine resources boom, so fishlike robot has become a hot topic in the field of robotics. Fishlike robot with high efficiency, good mobility and low noise, can be used in the underwater environment for a long time, with wide-range performance and complex conditions. The thunniform mode fishlike robot has high capabilities of propulsion and high maneuverability, gradually becomes a research focus. Depends on the Self-Planned Task of State Key Laboratory of Robotics and System (HIT), the basic theory of hydrodynamic characteristics of thunniform fish swimming is developed.This paper presents an algorithm about speed of steady state swimming, which is based on three coordinate systems. Starting from the classical mechanics, we derived kinetic theory equations of the fishlike robot swimming and solve it with fluid dynamics equations to realize the steady state swimming. Apply this algorithm to simulate the whole process of steady-state swimming for example in order to verify the correctness of this algorithm.Based on this algorithm, the paper analyzed the behavior of the fishlike robot's body, caudal fin and head to obtain influential parameters, which include the body's heaving amplitude, frequency and wavelength; the fin's largest attack angle and the phase of heaving and pitching motion of caudal fin motion; the amplitude of the head's front-end and the amplitude of the robot's center. We simulated the motion of the fishlike robot under difference parameters to obtain the influence between these parameters and the speed, force, power consumption and efficiency. We studied all of these from three aspects, kinematics, energetic and wake structure, to investigate the law of the fishlike robot improve the efficiency using the energy of the flow.In this paper, the main research method is composed by the theory research and simulating analyzing. We improved the theory of the steady state swimming and revealed the influences of the motion parameters. All of these would provide theoretical basis for the development of the fishlike robot and its motion control.