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The Effect of Flexibility and Aspect Ratios on Ribbon-Fin-Propulsion
Title
The Effect of Flexibility and Aspect Ratios on Ribbon-Fin-Propulsion.
Creator
Liu, Hanlin, Taylor, Bevan, Lashaw, Evan, Graduate College, Curet, Oscar M.
Abstract/Description
Ribbon-fin-based propulsion has the potential to improve the maneuverability of underwater vehicles in complex environments. In this type of propulsion a series of rays are used to send traveling waves along an elongated fin, which is referred to as ribbon fin. In this work, in order to know the effect of flexural rigidities and aspect ratios on undulating ribbon fin propulsion; we built a robotic ribbon fin, and tested the physical model in a water flume. In a series of experiments we...
Show moreRibbon-fin-based propulsion has the potential to improve the maneuverability of underwater vehicles in complex environments. In this type of propulsion a series of rays are used to send traveling waves along an elongated fin, which is referred to as ribbon fin. In this work, in order to know the effect of flexural rigidities and aspect ratios on undulating ribbon fin propulsion; we built a robotic ribbon fin, and tested the physical model in a water flume. In a series of experiments we measured the propulsive force, power consumption and the free-swimming speed of the robotic fin as a function of wave frequency for fins with different ray stiffness and aspect ratios. The propulsive performance of the robotic ribbon fin was based on the propulsive force generated and power consumption. A series of kinematic experiments were performed using a high-speed camera. Based on the fin kinematics, the natural frequencies of the ribbon fin with different stiffness were determined. We found that the flexible rays would improve or worsen the propulsive performance compared to a rigid counterpart depending on the actuation parameters. For the aspect ratios considered, the propulsive efficiency improves with increase in the fin height. Our data suggest that, the ribbon fin can yield best propulsive behavior close to its natural frequency.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00005881
Format
Document (PDF)
Propulsive performance of an under-actuated robotic ribbon fin
Title
Propulsive performance of an under-actuated robotic ribbon fin.
Creator
Liu, Hanlin, Curet, Oscar M
Date Issued
2017-06-02
PURL
http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1088_1748-3190_aa7184_1642527109
Format
Document (PDF)
Propulsive Performance and Maneuver Control of Undulatory Ribbon Fin Propulsion Using Bio-inspired Robotic Systems
Title
Propulsive Performance and Maneuver Control of Undulatory Ribbon Fin Propulsion Using Bio-inspired Robotic Systems.
Creator
Liu, Hanlin, Curet, Oscar M., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Undulatory ribbon- n-based propulsion is an appealing propulsion mechanism due to its rich locomotor capabilities that can improve the propulsive performance and maneuverability of underwater vehicles. For instance, the swimming mechanics of weakly electric black ghost knife sh (Apteronotus albifrons) is of great interest to study because of their high swimming e ciency at low speeds and extraordinary agility such as rapid reversal swimming, hovering in presence of water disturbance, rolling...
Show moreUndulatory ribbon- n-based propulsion is an appealing propulsion mechanism due to its rich locomotor capabilities that can improve the propulsive performance and maneuverability of underwater vehicles. For instance, the swimming mechanics of weakly electric black ghost knife sh (Apteronotus albifrons) is of great interest to study because of their high swimming e ciency at low speeds and extraordinary agility such as rapid reversal swimming, hovering in presence of water disturbance, rolling and vertical swimming. In this thesis work, to facilitate our understanding on the exible undulatory ribbon n propulsion, we have four research motivations. The rst objective is to study how the use of exible rays and di erent n morphology can in uence the propulsive performance of ribbon- n propulsion. It is possible that natural swimmers using this locomotion method could take advantage of passive n motion based on the coupling of uid-structure interaction and the elasto-mechanical responses of the undulating n. Therefore, the second objective is to understand how an under-actuated undulating n can take advantage of natural dynamics of the uid-structure interaction for the propulsive force generation. In addition to the impressive propulsive performance of the undulatory n propulsion, the exceptional maneuverability of knife sh is also a key motivation that drives this thesis work. Thus, we dedicate to investigate how traveling wave shapes and actuation parameters (frequency, wavelength) can manipulate the maneuvering behaviors of a swimmer propelled by an undulating ribbon n. Lastly, we aim to uncover the e ect of varying traveling wave amplitudes and pectoral ns on its maneuvering performances. Two robotic devices were developed to study the propulsive performance of both fullyactuated and under-actuated ribbon n propulsion and investigate the maneuver control of a free-swimming underwater robot propelled by an undulatory n. For the rst research aim, we study the e ect of exible rays and di erent n morphology on the propulsive performance of ribbon- n propulsion. A physical model composed of fteen rays interconnected with an elastic membrane was used to test four di erent ray exural sti ness and four aspect ratios. Our results show that exible rays can improve the propulsive e ciency compared to a rigid counterpart. In addition, the morphology of the ribbon n a ects its propulsive performance as well, and there could exist an optimal n morphology. To understand how an underactuated undulating n can modify its active and passive n motion to e ectively control the hydrodynamic force and propulsive e ciency. We did a series of experiments using the same robotic n model but with some structural modi cations and we measured n kinematics, net surge force and power consumption. We nd that the under-actuated n can keep the equivalent propulsive e ciency as the fully-actuated counterpart within our experimental parameter range. Moreover, our results demonstrate that the thrust force and power consumption of an under-actuated n follow the same scaling laws as the fully-actuated n. To conduct the free-swimming maneuver study, we developed a self-contained, free-swimming robot propelled by an undulatory n, which is able to perform the following maneuvers: forward, reversed swimming and hovering motion. We also performed V3V PIV experiments to capture the ow structures generated by the robotic device. Our results show that the robot can reach higher swimming e ciency at low frequencies. As the number of traveling waves increases, the robot swims more stably in roll, pitch and yaw motions. For cases with varying wave amplitudes, traveling wave with incremental wave amplitude can achieve free-swimming velocity higher than that of decremental wave amplitude. However, the latter case can generate higher pitch angles. For the robot with slightly negative-pitched pectoral ns, it can perform slow diving maneuvers. These ndings demonstrate that we can take advantage of the undulating ribbon n propulsion to achieve high maneuverability for the future underwater vehicles in complex environment.
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Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00004853, http://purl.flvc.org/fau/fd/FA00004853
Subject Headings
Underwater propulsion., Wave-motion, Theory of., Remote submersibles--Design., Marine engineering.
Format
Document (PDF)