Biomimetic Cuttlefish Robot And Its Key Technology Research

The 21st century is the century of ocean. With the rapid development of science and technology, human beings begin to explore and utilize the marine resources more quickly. The underwater robots (Unmanned Underwater Vehicle, UUV) with the functions of exploration, salvage, detection and tracing have become important tools to explore ocean. In this paper, the cuttlefish is chosen as the bionic object. Based on analysis of their morphological character and swimming mechanism, a kind of biomimetic cuttlefish-like underwater robot actuated by shape memory alloy (SMA) wires has been developed, which can be propelled by jetting and undulating fin. The performance of the biomimetic robot and its parts has been studied through experiment as well. The research provides a new way to imitate jetting and undulating fin for biomimetic underwater robots research and provides basis for the subsequent development.Cuttlefish belong to cephalopoda class of marine mollusks. They can swim flexibly like fish through jetting and undulating fin. Moreover they can turn with zero radius and swim backward fast, which is difficult for fish. Through analysis of the swimming mode and force acting on cuttlefish, the kinematic model and dynamic model of undulating fin were established, including its hydrodynamics character. The kinematic model of the cross-section of mantle of cuttlefish was established, and variation of the thrust of jet with the contraction of the mantle was analyzed. The three-dimensional model of cuttlefish was established and the drag force due to its profile during the swimming process was also analyzed.The intramuscular structure and the action process of the cuttlefish fin are analyzed. Then an improved biomimetic flexible fin unit actuated by SMA wires which exhibits more symmetry in action process is investigated. The forces generated during the bending process are researched by experiments. Theory calculation shows that the maximum output force is 3.75 N and the corresponding maximum angular velocity is 141.74 rad/s. Based on the biomimetic flexible fin unit, a biomimetic manta ray robot fish is developed. It can swim silently with good stability. Its maximum swimming speed in line is 79 mm/s and its minimum turning radius can achieve 118 mm. Imitating the physical structure and movement pattern of the cuttlefish fin, a biomimetic horizontal fin based on the flexible fin unit is designed. The factors that affect the propulsive force of the biomimetic horizontal fin are analyzed by simulation. When the series of flexible fin units move up and down in a certain sequence, the biomimetic fin undulates like a wave to generate propulsive force. The experimental results showe that the forces vary periodically. The maximum instantaneous value is 169 mN and the average value is 80 mN. A vehicle propelled by the biomimetic level pectoral fin is developed. Its maximum swimming speed can achive 35 mm/s.Through analyzing the muscle structure of the mantle of cuttlefish and its movement character, a biomimetic jetting system is designed. The system includes a biomimetic mantle, a biomimetic funnel and a biomimetic membrane switch. All the parts are actuated by SMA wires. The biomimetic mantle can contract flexibly and evenly. The maximum contraction strain of SMA wires embedded in the biomimetic mantle can reach 2.59% and the maximum cross-section strain can reach 17.55%. The biomimetic funnel can bend in any direction and the maximum bending angle is 22°. The experiment shows that the biomimetic jetting system can be propelled by jetting like cuttlefish via expansion and contraction of the biomimetic mantle. The jetting thrust is affected by many factors, such as voltage, pulse width, water temperature and diameter of the biomimetic funnel. The maximum instantaneous thrust of the biomimetic jetting system is 600 mN and its maximum swimming speed is 87.6 mm/s.Imitating the shape of cuttlefish and considering all the propulsive and control hardware system, a biomimetic cuttlefish robot is designed a biomimetic cuttlefish robot prototype is fabricated based CAN bus control systems. The present prototype can swim in complex ways, combining undulate fin propulsion and jet propulsion. It is able to move forward, backward and in turning. The maximum swimming speed is 35 mm/s, closing to the cruise speed of cuttlefish. The prototype can turn with zero radius. This character can improve the robot's mobility and enhance its ability to adapt to complex environments.In summary, the biomimetic cuttlefish robot and its key technology are researched. The biomimetic manta ray, biomimetic horizontal fin, biomimetic jetting system and the biomimetic cuttlefish prototype are developed. The present research provides experimental platform for further study.