A dynamic model for underwater robotic fish with a servo actuated pectoral fin

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.

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Robotic Fish Propelled by a Servo Motor and Ionic Polymer-Metal Composite Hybrid Tail

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4043101 ◽

2019 ◽

Vol 141 (7) ◽

Cited By ~ 3

Author(s):

Zheng Chen ◽

Piqi Hou ◽

Zhihang Ye

Keyword(s):

Steady State ◽

Dynamic Model ◽

Robotic Fish ◽

Metal Composite ◽

Ionic Polymer Metal Composite ◽

Servo Motor ◽

Ionic Polymer ◽

Soft Actuator ◽

Polymer Metal ◽

Motion Dynamics

In this paper, a new robotic fish propelled by a hybrid tail, which is actuated by two active joints, is developed. The first joint is driven by a servo motor, which generates flapping motions for main propulsion. The second joint is actuated by a soft actuator, an ionic polymer-metal composite (IPMC) artificial muscle, which directs the propelled fluid for steering. A state-space dynamic model is developed to capture the two-dimensional (2D) motion dynamics of the robotic fish. The model fully captures the actuation dynamics of the IPMC soft actuator, two-link tail motion dynamics, and body motion dynamics. Experimental results have shown that the robotic fish is capable of swimming forward (up to 0.45 body length/s) and turning left and right (up to 40 deg/s) with a small turning radius (less than half a body length). Finally, the dynamic model has been validated with experimental data, in terms of steady-state forward speed and turning speed at steady-state versus flapping frequency.

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

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-11-2014-0426 ◽

2015 ◽

Vol 42 (3) ◽

pp. 214-221 ◽

Cited By ~ 8

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.

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Bio-harmonized Dynamic Model of a Biology Inspired Carangiform Robotic Fish Underwater Vehicle

IFAC Proceedings Volumes ◽

10.3182/20140824-6-za-1003.02797 ◽

2014 ◽

Vol 47 (3) ◽

pp. 7258-7265 ◽

Cited By ~ 2

Author(s):

Abhra Roy Chowdhury ◽

Bhuneshwar Prasad ◽

Vinoth Vishwanathan ◽

Rajesh Kumar ◽

S K Panda

Keyword(s):

Dynamic Model ◽

Underwater Vehicle ◽

Robotic Fish

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

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-04-2020-0081 ◽

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.

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A dynamic model for tail-actuated robotic fish with drag coefficient adaptation

Mechatronics ◽

10.1016/j.mechatronics.2013.07.005 ◽

2013 ◽

Vol 23 (6) ◽

pp. 659-668 ◽

Cited By ~ 32

Author(s):

Jianxun Wang ◽

Xiaobo Tan

Keyword(s):

Drag Coefficient ◽

Dynamic Model ◽

Robotic Fish

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.620.502 ◽

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.

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