Theoretical And Experimental Research On Caudal-fin Propulsion System

The research and development on fish-like propulsion have been injected with strong power because of the ocean development since 1950 s. With the raise of Chinese Ocean Strategy, the research strength in propulsion system on or beneath the water is becoming more and more strong. Compared with the existing propeller propulsion mode, fish's excellent swimming performance has caused wide attention of international and domestic academics. As a major propulsion mode in biofish propulsion, the caudal fin propulsion has become a hot research subject in the field of biofish propulsion result from as its swimming characteristics of big thrust force, high propulsive efficiency, easy to be popularized and applied. This paper sets caudal fin of carangiform fish as the imitating object which is the most representative mode in caudal fin propulsion. Based on the motion characteristics of the linear pendulum hypocycloid planetary gear train, the prototype production and the experimental study of caudal-fin propulsion system were conducted from the point of being easy to be applied and the integration of motion and transmission. Specific research contents include the followings:1. Based on the easily spreading bionic principle of motor +mechanical transmission device, through the observation and analysis study of carangiform fish, combined with the design method of black box, a assumption was put forward that swimming of carangiform fish could be imitated by the transmission method of the linear pendulum hypocycloid planetary gear train; Based on characteristics of 2 joints caudal fin's planar composite movement, combined with the triangle in motion form of planar linkage mechanisms.the two-joint caudal-fin propulsion system was designed based on the linear pendulum hypocycloid planetary gear train by fitting the movement of the live fish's caudal fin.2. According to the design scheme of linear pendulum hypocycloid caudal-fin propulsion system, the development of caudal-fin propulsion system prototype was carried out, mainly includes the design of structure and the study of control system. Based on the mechanism principle of propulsion system, the structure design and 3-d modeling of the propulsion system were completed. The rationality of the structure was preliminarily tested by motion simulation; Aimed at the drive way needed by caudal-fin propulsion system, a hardware circuit based on the QZ-DCC9010 controller of servo motor was designed; Based on the design of structure design and the control system, the prototype's design and manufacturing of the propulsion system was finally completed.3. Sources of propulsion are mainly: the lift, the trailing vortex, the leading edge suction. Aimed the various sources, corresponding calculation models were established. Based on the hydrodynamic analysis of carangiform caudal fin during oscillation, the freely4. advancing & swinging experimental platform was designed and produced.The indoor reflux tank was designed which could simulate the water flows. And then, the measuring devices were debugged. At last, the specification and the optimization of experiments were finished.5. Aimed at the parameters which could effect the performance of the caudal-fin propulsion system. A series of contrast experiments were conducted which fit the caudal-fin propulsion system and freely advancing & swinging experimental platform. And detailed analysis of the experimental data was completed to find out the optimal parameters of the caudal-fin propulsion system.