Ấn phẩm:
Dynamic analysis and motion control of a fish robot driven by pectoral fins
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Demand for a novel propulsion system, which is not only more efficient than the traditional impetus structure but also more friendly to the environment, is a reason for study on robots thrust by fish-inspired fins. Meanwhile, pectoral fins of biological fish play a crucial role in locomotion mechanism, in particular, only a small ratio of natural fish use the pectoral fins as the principal propelling component. Nevertheless, most of the rest ratio use these fins for maneuverability and stability of swimming movements. Accelerating, braking, stabling the position, and cruising in short distances are the behaviors of fish while employing pectoral fins. On the other hand, the dynamics model of pectoral fins with flexibility and diversity of shape is a significant factor, which has not mentioned in previous work. In an attempt to generate a counterpart of biological fish, this dissertation recommends several novel approaches in designing, analyzing, and establishing the mathematical model for a fish-like robot with pectoral fins.
Inspired by natural fish fin, the dissertation concentrates on flexible structures that allow generating smooth motion, low energy expenditure, and efficient thrust. The fact proves that compliant fins of natural fish own high propulsive efficiency. Three variation types of pectoral fins comprising uniform ones, non-uniform ones, and folding ones were investigated. First, the modeling issue of the robot with uniform fins was conducted. The fins were considered as cantilever beams. An appended simplistic controller was then designed to track the referent trajectories of direction and surge velocity. Second, to imitate the biological fish fin, the shape of snakehead fish was adopted. Its mathematical model was established with the assistant of the Rayleigh-Ritz method in deflection modeling. Finally, to improve the fish robot's swimming speed as well as energy consumption efficiency, artificial folding pectoral fin-type, which is inspired by the change of drag/thrust area ratio of a natural fish fin, was proposed. The computation model of the above types is established on the base of body rigid dynamics and Morison's force. Wherein the fluid influences on the fin movements are described as separated elements of added mass and damping. For two last fin types, the Lagrange approach was applied to build dynamic equations of motion. Moreover, experimental works are carried out to validate and evaluate the recommended models. The achieved results confirmed that the proposals are feasible and able to predict the behavior of the robot relatively well. Remarkably, the robotic fish with folding pectoral fins can attain faster movement speed and better maneuverability compared with previous designs using the same pectoral fins. In detail, the robot can reach an average velocity of 0.58 BL/s (0.231 m/s ) and a turning radius of 0.63 BL (0.25m) in correspondence to forward swimming motion and turning motion. Furthermore, the peak of velocity performance obtains 0.78 BL/s (0.308 m/s). On the other hand, it is revealed that the folding pectoral fins with reasonably flexible joints provide better speed performance than the high stiffness ones.
As an obtained achievement, the outcome of the dissertation can be promoted to design practical control algorithms, which track following the desired trajectory or interact with the surrounding environment. Furthermore, it can be expanded on the optimization issues of motion responses. Some future trends can be addressed to tackle challenges for improving swimming efficiency as well as building a more complex dynamic model of three-dimensional motion.
Mô tả
152 tr.
Tác giả
Pham, Van Anh
Người hướng dẫn
Võ, Tường Quân
Nguyễn, Tấn Tiến
Nguyễn, Tấn Tiến
Nơi xuất bản
Nhà xuất bản
Trường Đại học Bách khoa
Năm xuất bản
2020
ISSN tạp chí
Nhan đề tập
Từ khóa chủ đề
Mechanics, Applied. , Robot. , Mechanical engineering. , Cơ học ứng dụng. , Cơ khí.