The Desige Of Structure And Experiment Of On Flexible Biomimetic Fish Fin Based On Shape Memory Alloy

The research on flexible biomimetic fish fin based on intelligent materials is one of hot topics in underwater robotic area. There exists great difference between electro-mechanical system and animal muscle on driven principle, form, performance, etc., particularly lacks efficient energy storage element that similar to the muscle tendon of animals. Therefore, we further carry out research on smart material driven bio-fin, the character of which is much close to muscles. A new actuator driven by smart material is initially investigated, which provides an innovative idea and another choice for the bionic design of underwater vehicles.Firstly, according to the research and study on literature and the experience of our research group, shape memory alloy have a high ratio of power to weight, the characteristic of driver and sensor, the great ratio of deformation and other advantages ,which make it be foreground in the field of smart materials application. This paper is based on comparative analysis of variety of functional materials, choosing NiTi shape memory alloy.Secondly, a couple of differentially equipped SMA plates with single Shape Memory Effect (SME) act as the function of fin ray, according to the structure of flexible bio-fin along with the characteristic of SMA,. The deformation information is detected and feedback by strain transducer, and then achieve both oscillatory and undulatory motion of the flexible fin through Fuzzy Logic Control (FLC) algorithm. The preliminary experiments present the relationship between the bending force and the thickness of SMA plate, the relationship between the maximal bending angle and the thickness of SMA plate, and the relationship between the maximal bending angle and the heating current. This is meant for an initial optimal design of SMA bio-fin. Finally, to verify the temperature controlling performance the of shape memory alloys drive, the experiments are proceeded with the deflection of the system. As the force and frequency response constraining mutual, the design of structure and drive system needs further improvement and optimization.The dissertation finally gave the summary to research work above-mentioned and pointed out some future work.