A biomimetic cownose ray robot fish with oscillating and chordwise twisting flexible pectoral fins

2015 ◽  
Vol 42 (3) ◽  
pp. 214-221 ◽  
Author(s):  
Hongwei Ma ◽  
Yueri Cai ◽  
Yuliang Wang ◽  
Shusheng Bi ◽  
Zhao Gong
Keyword(s):  
Swimming Performance ◽  
Robotic Fish ◽  
Small Radius ◽  
Water Tank ◽  
Pectoral Fin ◽  
Content Type ◽  
Pectoral Fins ◽  
Propulsion Performance ◽  
Cownose Ray ◽  
And Control

Purpose The paper aims to develop a cownose ray-inspired robotic fish which can be propelled by oscillating and chordwise twisting pectoral fins. Design/methodology/approach The bionic pectoral fin which can simultaneously realize the combination of oscillating motion and chordwise twisting motion is designed based on analyzing the movement of cownose ray’s pectoral fins. The structural design and control system construction of the robotic fish are presented. Finally, a series of swimming experiments are carried out to verify the effectiveness of the design for the bionic pectoral fin. Findings The experimental results show that the deformation of the bionic pectoral fin can be well close to that of the cownose ray’s. The bionic pectoral fin can produce effective angle of attack, and the thrust generated can propel robotic fish effectively. Furthermore, the tests of swimming performance in the water tank show that the robotic fish can achieve a maximum forward speed of 0.43 m/s (0.94 times of body length per second) and an excellent turning maneuverability with a small radius. Originality/value The oscillating and pitching motion can be obtained simultaneously by the active control of chordwise twisting motion of the bionic pectoral fin, which can better imitate the movement of cownose ray’s pectoral fin. The designed bionic pectoral fin can provide an experimental platform for further study of the effect of the spanwise and chordwise flexibility on propulsion performance.

Research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hongwei Ma ◽  
Shuai Ren ◽  
Junxiang Wang ◽  
Hui Ren ◽  
Yang Liu ◽  
...  
Keyword(s):  
Ground Effect ◽  
Robotic Fish ◽  
Two Dimensional ◽  
Pectoral Fin ◽  
Content Type ◽  
Pectoral Fins ◽  
Propulsion Performance ◽  
Effect Model ◽  
Hydrodynamic Experiments ◽  
Flexible Deformation

Purpose This paper aims to carry out the research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins. Design/methodology/approach The two-dimensional ground effect model of the oscillating pectoral fin without considering flexible deformation is established by introducing a two-dimensional fluid ground effect model. The parameters of the influence of ground effect on the oscillating pectoral fin are analyzed. Finally, the ground effect test platform is built, and a series of hydrodynamic experiments are carried out to study the influence of ground effect on the propulsion performance of the robotic fish propelled by oscillating paired pectoral fins under different motion parameters. Findings The thickness of the trailing edge and effective clearance are two important parameters that can change the influence of ground effect on the rigid pectoral fin. The experimental results are consistent with that obtained through theoretical analysis within a certain extent, which indicates that the developed two-dimensional ground effect model in this paper can be used to analyze the influence of ground effect on the propulsion performance of the oscillating pectoral fin. The experiment results show that the average thrust increases with the decreasing distance between the robot fish and the bottom. Meanwhile, with the increase of oscillation frequency and amplitude, the average thrust increases gradually. Originality/value The developed two-dimensional ground effect model provides the theoretical basis for the further research on the influence of ground effect on the propulsion performance of the oscillating pectoral fin. It can also be used in the design of the bionic pectoral fins.

Motion Control for a Stingray-Like Robotic Fish with Undulating Pectoral Fins

2014 ◽  
Vol 620 ◽  
pp. 502-507
Author(s):  
Yang Wei Wang ◽  
Bao Tong Gu ◽  
Jin Bo Tan ◽  
Peng Fei Sang
Keyword(s):  
Control System ◽  
Motion Control ◽  
Control Strategies ◽  
Robotic Fish ◽  
Entire Length ◽  
Water Tank ◽  
Control Methods ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Undulating Fin

Stingrays have expanded and highly flexible pectoral fins that extend over the entire length of their body. Locomotion is controlled by modulations of the undulating fin surface which produce steady swimming, acceleration, or complex maneuvers. In this paper, a robotic fish inspired by stingray was presented. Structure of the biomimetic prototype and layout of the control system were illustrated. In order to mimic the undulations, parameters of the biomimetic pectoral fin need to be accurately controlled including frequency, amplitude, wavelength, and undulatory mode. Several control strategies were proposed to realize different kinds of locomotion. Lastly, swimming experiments were carried out in the water tank according to the control methods. Experiment results demonstrate the viability of our methods.

Applying central pattern generators to control the robofish with oscillating pectoral fins

2015 ◽  
Vol 42 (5) ◽  
pp. 392-405 ◽  
Author(s):  
Yong Cao ◽  
Shusheng Bi ◽  
Yueri Cai ◽  
Yuliang Wang
Keyword(s):  
Design Methodology ◽  
Three Dimensional ◽  
Central Pattern Generators ◽  
Content Type ◽  
Pectoral Fins ◽  
Cownose Ray ◽  
Pattern Generators ◽  
And Control ◽  
Scientific Tool ◽  
Oscillation Characteristics

Purpose – This paper aims to develop a robofish with oscillating pectoral fins, and control it to mimic the bionic prototype by central pattern generators (CPGs). Design/methodology/approach – First, the oscillation characteristics of the cownose ray were analyzed quantitatively. Second, a robofish with multi-joint pectoral fins was developed according to the bionic morphology and kinematics. Third, the improved phase oscillator was established, which contains a spatial asymmetric coefficient and a temporal asymmetric coefficient. Moreover, the CPG network is created to mimic the cownose ray and accomplish three-dimensional (3D) motions. Finally, the experiments were done to test the authors ' works. Findings – The results demonstrate that the CPGs is effective to control the robofish to imitate the cownose ray realistically. In addition, the robofish is able to accomplish 3D motions of high maneuverability, and change among different swimming modes quickly and smoothly. Originality/value – The research provides the method to develop a robofish from both 3D morphology and kinematics. The motion analysis and CPG control make sure that the robofish has the features of high maneuverability and camouflage. It is useful for military underwater applications and underwater detections in narrow environments. Second, this work lays the foundation for the autonomous 3D control. Moreover, the robotic fish can be taken as a scientific tool for the fluid bionics research.

Dynamic modeling of a flexible oscillating pectoral fin for robotic fish

2014 ◽  
Vol 41 (5) ◽  
pp. 421-428 ◽  
Author(s):  
Shusheng Bi ◽  
Hongwei Ma ◽  
Yueri Cai ◽  
Chuanmeng Niu ◽  
Yuliang Wang
Keyword(s):  
Dynamic Model ◽  
Kinematic Model ◽  
Analytical Calculation ◽  
Experimental Results ◽  
Pectoral Fin ◽  
Content Type ◽  
Pectoral Fins ◽  
Propulsion Performance ◽  
Propulsion Mechanism ◽  
Flexible Deformation

Purpose – The paper aims to present a dynamic model of flexible oscillating pectoral fin for further study on its propulsion mechanism. Design/methodology/approach – The chordwise and spanwise motions of cow-nosed ray’s pectoral fin are first analyzed based on the mechanism of active/passive flexible deformation. The kinematic model of oscillating pectoral fin is established by introducing the flexible deformation. Then, the dynamic model of the oscillating pectoral fin is developed based on the quasi-steady blade element theory. A series of hydrodynamic experiments on the oscillating pectoral fin are carried out to investigate the influences of motion parameters on the propulsion performance of the oscillating pectoral fin. Findings – The experimental results are consistent with that obtained through analytical calculation within a certain range, which indicates that the developed dynamic model in this paper is applicable to describe the dynamic characteristics of the oscillating pectoral fin approximately. The experimental results show that the average thrust of an oscillating pectoral fin increases with the increasing oscillating amplitude and frequency. However, the relationship between the average thrust and the oscillating frequency is nonlinear. Moreover, the experimental results show that there is an optimal phase difference at which the oscillating pectoral fin achieves the maximum average thrust. Originality/value – The developed dynamic model provides the theoretical basis for further research on propulsion mechanism of oscillating pectoral fins. It can also be used in the design of the bionic pectoral fins.

Design and Dynamic Modeling of a Flexible Feathering Joint for Robotic Fish Pectoral Fins

2014 ◽  
Author(s):  
Sanaz Bazaz Behbahani ◽  
Xiaobo Tan
Keyword(s):  
Dynamic Model ◽  
Robotic Fish ◽  
Power Stroke ◽  
Hydrodynamic Drag ◽  
Pectoral Fin ◽  
Flexible Joint ◽  
Blade Element Theory ◽  
Pectoral Fins ◽  
Flexible Part ◽  
Recovery Stroke

In this paper, we propose a novel design for a pectoral fin joint of a robotic fish. This joint uses a flexible part to enable the rowing pectoral fin to feather passively and thus reduce the hydrodynamic drag in the recovery stroke. On the other hand, a mechanical stopper allows the fin to maintain its motion prescribed by the servomotor in the power stroke. The design results in net thrust even when the fin is actuated symmetrically for the power and recovery strokes. A dynamic model for this joint and for a pectoral fin-actuated robotic fish involving such joints is presented. The pectoral fin is modeled as a rigid plate connected to the servo arm through a pair of torsional spring and damper that describes the flexible joint. The hydrodynamic force on the fin is evaluated with blade element theory, where all three components of the force are considered due to the feathering degree of freedom of the fin. Experimental results on robotic fish prototype are provided to support the effectiveness of the design and the presented dynamic model. We utilize three different joints (with different sizes and different flexible materials), produced with a multi-material 3D printer, and measure the feathering angles of the joints and the forward swimming velocities of the robotic fish. Good match between the model predictions and experimental data is achieved, and the advantage of the proposed flexible joint over a rigid joint, where the power and recovery strokes have to be actuated at different speeds to produce thrust, is demonstrated.

Effect of Morphological Fin-Curl on the Swimming Performance and Station-Holding Ability of Juvenile Shovelnose Sturgeon

2016 ◽  
Vol 7 (1) ◽  
pp. 198-204 ◽  
Author(s):  
David Deslauriers ◽  
Ryan Johnston ◽  
Steven R. Chipps
Keyword(s):  
Swimming Speed ◽  
Early Onset ◽  
Positive Relationship ◽  
Swimming Performance ◽  
Fork Length ◽  
Critical Swimming Speed ◽  
Pectoral Fin ◽  
Speed Test ◽  
Shovelnose Sturgeon ◽  
Pectoral Fins

Abstract We assessed the effect of fin-curl on the swimming and station-holding ability of juvenile shovelnose sturgeon Scaphirhynchus platorynchus (mean fork length = 17 cm; mean weight = 16 g; n = 21) using a critical swimming speed test performed in a small swim chamber (90 L) at 20°C. We quantified fin-curl severity using the pectoral fin index. Results showed a positive relationship between pectoral fin index and critical swimming speed indicative of reduced swimming performance displayed by fish afflicted with a pectoral fin index < 8%. Fin-curl severity, however, did not affect the station-holding ability of individual fish. Rather, fish affected with severe fin-curl were likely unable to use their pectoral fins to position their body adequately in the water column, which led to the early onset of fatigue. Results generated from this study should serve as an important consideration for future stocking practices.

Development and target following of vision-based autonomous robotic fish

Robotica ◽  
2009 ◽  
Vol 27 (7) ◽  
pp. 1075-1089 ◽  
Author(s):  
Yonghui Hu ◽  
Wei Zhao ◽  
Guangming Xie ◽  
Long Wang
Keyword(s):  
Visual Information ◽  
Fuzzy Logic Controller ◽  
Swimming Performance ◽  
Mean Shift ◽  
Digital Camera ◽  
Robotic Fish ◽  
Pectoral Fins ◽  
Underwater Image ◽  
Swimming Pattern ◽  
Camshift Algorithm

SUMMARYA novel ostraciiform swimming, vision-based autonomous robotic fish is developed in this paper. Its feasibility and capability are shown by implementing a dynamic target following task in a swimming pool. Inspired by boxfish that is highly stable and fairly maneuverable, the robotic fish is designed and constructed by locating multiple propulsors peripherally around a rigid body. Swimming locomotion of the robotic fish is achieved through harmonic oscillations of the tail and pectoral fins. The forces and moments acting on the fins and body are analyzed and the governing motion equations are derived. Through coordinating the movements of the propulsors, several typical swimming patters are empirical designed and realized. A digital camera is integrated in the robotic fish, and the visual information is processed with the embedded microcontroller. To treat the degradation of underwater image, a continuously adaptive mean shift (Camshift) algorithm is modified to keep visual lock on the moving target. A fuzzy logic controller is designed for motion regulation of a hybrid swimming pattern, which employs synchronized pectoral fins for thrust generation and tail fin for steering. A simple target following task is designed via an autonomous robotic fish swimming after a manually controlled robotic fish with fixed distance. The swimming performance of the robotic fish is tested and the effectiveness of the proposed target following method is verified experimentally.

scholarly journals Development of High-Performance Soft Robotic Fish by Numerical Coupling Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Wenjing Zhao ◽  
Aiguo Ming ◽  
Makoto Shimojo
Keyword(s):  
High Performance ◽  
Fiber Composite ◽  
Swimming Performance ◽  
Structural Parameters ◽  
Robotic Fish ◽  
Dynamic Responses ◽  
Flexible Structure ◽  
Swimming Velocity ◽  
Coupling Analysis ◽  
And Control

To design a soft robotic fish with high performance by a biomimetic method, we are developing a soft robotic fish using piezoelectric fiber composite (PFC) as a flexible actuator. Compared with the conventional rigid robotic fish, the design and control of a soft robotic fish are difficult due to large deformation of flexible structure and complicated coupling dynamics with fluid. That is why the design and control method of soft robotic fish have not been established and they motivate us to make a further study by considering the interaction between flexible structure and surrounding fluid. In this paper, acoustic fluid-structural coupling analysis is applied to consider the fluid effect and predict the dynamic responses of soft robotic fish in the fluid. Basic governing equations of soft robotic fish in the fluid are firstly described. The numerical coupling analysis is then carried out based on different structural parameters of soft robotic fish. Through the numerical analysis, a new soft robotic fish is finally designed, and experimental evaluation is performed. It is confirmed that the larger swimming velocity and better fish-like swimming performance are obtained from the new soft robotic fish. The new soft robotic fish is developed successfully for high performance.

Bio-Inspired Robotic Cownose Ray Propelled by Electroactive Polymer Pectoral Fin

2011 ◽  
Author(s):  
Zheng Chen ◽  
Tae I. Um ◽  
Jianzhong Zhu ◽  
Hilary Bart-Smith
Keyword(s):  
Twist Angle ◽  
Lithium Ion ◽  
Leading Edge ◽  
Pdms Membrane ◽  
Metal Composite ◽  
Pectoral Fin ◽  
Free Swimming ◽  
Axial Tomography ◽  
Pectoral Fins ◽  
Cownose Ray

The cownose ray (Rhinoptera bonasus) demonstrates excellent swimming capabilities; generating highly efficient thrust via flapping of dorsally flattened pectoral fins. In this paper, we present a bio-inspired and free swimming robot that mimics the swimming behavior of the cownose ray. The robot has two artificial pectoral fins to generate thrust through a twisted flapping motion. Each artificial pectoral fin consists of one ionic polymer-metal composite (IPMC) as artificial muscle in the leading edge and a passive PDMS membrane in the trailing edge. By applying voltage signal to the IPMC, the passive PDMS membrane follows the bending of IPMC with a phase delay, which leads to a twist angle on the fin. The characterization results have shown that the pectoral fin was able to generate up to 40% tip deflection and 10° twist angle with less than 1 Watt power consumption. A bio-inspired rigid body was designed using Computerized Axial Tomography (CT Scan) data of the cownose ray body and printed using a 3-dimensional printer. A light and compact on-board control unit with a lithium ion polymer battery has been developed for the free swimming robot. Experimental results have shown that the robot swam at 0.034 BL/S.

Numerical Study of Batoid with Asymmetrically Undulating Pectoral Fins

2013 ◽  
Vol 307 ◽  
pp. 89-96
Author(s):  
Zhi Jun Wu ◽  
Wei Shan Chen ◽  
Jun Kao Liu ◽  
Sheng Jun Shi
Keyword(s):  
Dynamic Simulation ◽  
Numerical Study ◽  
Swimming Performance ◽  
Three Dimensional ◽  
Dynamic Parameters ◽  
Pectoral Fin ◽  
Symmetric Motion ◽  
Pectoral Fins ◽  
Simulation Results ◽  
The Difference

This paper presents a numerical study of three dimensional flows around a self-propelled batoid with asymmetrically undulating pectoral fins. During the dynamic simulation, the difference of phase angle of the asymmetric motion is set to 180° between left pectoral fin and right pectoral fin. To evaluate the swimming performance of batoid with asymmetric undulating fins, kinematic and dynamic parameters have been used comparing with that of batoid with symmetric undulating fins. The simulation results show that asymmetric motion can achieve better starting and accelerating performance than symmetric motion.

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