Research On Squid Fin Like Propelle Based On SMA

As the development of ocean resource exploration and bionics, researchers have paid more and more attentions to biomimetic underwater robots. Many types of robot fish, which mimic the locomotion of fish swimming, have been built because of highly efficient swimming and good maneuverability of fish. However, many robot fish belonging to the body and/or caudal fin propulsion, simulate the soft movements of fish by motor-driven stiff joints, which results in complex structure and noise. It made their performance incomparable with the fish. Another problem of body and/or caudal fin propelled robot fish is that they are difficult to realize the movements of rotating around their axes and swimming backward, which are very practicable.Therefore, researched in this thesis.First, the swimming mechanics and fin structure of squid is analyzed and the fin undulation is studied. An undulating model of squid fin like propeller is established by mimicking the fin undulation. Many smart materials are studies, and shape memory alloy is the most fit actuator of the squid fin like propeller because of its smooth actuation, easy control method, and resistance to the surroundings (except the temperature). TiNi based SMA is applied because its high specific resistance, large recovery strain and stress, high energy density.And then, two kinds of squid fin like propellers are built, one of which consists of stiff fin rays, while the other of flexible fin rays. A control circuit is developed. It consists of a radio frequency remote control module, a processor module and an actuation module. It can activate many fin rays to realize different swimming movements.At last, actuation experiments are done to the 2 kinds propellers. The 4 fin rays 2-sided propeller and its control circuit are debugged, and its swimming experiments show that it can steering at the radius smaller than its body length. The experimental results of 10 fin rays 2-sided squid fin like propeller show that this propeller can swim forward and backward, and rotate around its axis, and it reached the straight swimming speed of 8 mm/s and the steering speed of 12°/s.Squid fin like propellers are studied and verified by experiments. The results show that this kind of propeller is noiseless, environmental compatible, can be actuated by low voltage, and can realize soft movements and good maneuverability.