• 로봇학회논문지
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• 제6권3호
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• pp.274-283
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• 2011

A simplified linearized dynamic equation for the propulsion force generation of an Ostraciiform fish robot with elastically jointed double caudal fins is derived in this paper. The caudal fin is divided into two segments and connected using an elastic joint. The second part of the caudal fin is actuated passively via the elastic joint connection by the actuation of the first part of it. It is demonstrated that the derived equation can be utilized for the design of effective caudal fins because the equation is given as an explicit form with several physical parameters. A simple Ostraciiform fish robot was designed and fabricated using a microprocessor, a servo motor, and acrylic plastics. Through the experiment with the fish robot, it is demonstrated that the propulsion force generated in the experiment matches well with the proposed equation, and the propulsion speed can be greatly improved using the elastically jointed double fins, improving the average speed more than 80%. Through numerical simulation and frequency domain analysis of the derived dynamic equations, it is concluded that the main reason of the performance improvement is resonance between two parts of the caudal fins.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1580-1586
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• 2003

This paper presents the design and the analysis of a "fish-like underwater robot". In order to develop swimming robot like a real fish, extensive hydrodynamic analysis were made followed by the study of biology of the fishes especially its maneuverability and propel styles. Swimming mode is achieved by mimicking fish-swimming of carangiform. This is the swimming mode of the fast motion using its tail and peduncle for propulsion. In order to generate configurations of vortices that gives efficient propulsion yawing and surging with a caudal fin has applied and in order to submerge and maintain the body balance pitching and heaving motion with a pair of pectoral fin is used. We have derived the equation of motion of PoTuna by two methods. In first method, we use the equation of motion of underwater vehicle with the potential flow theory for the power of propulsion. In second method, we apply the method of the equation of motion of UVM(Underwater Vehicle-Manipulator). Then, we compare these results.

• 한국정밀공학회지
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• 제33권7호
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• pp.571-577
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• 2016

In this paper, we propose a novel propulsion method for a Biomimetic underwater robot, which is a bio-inspired approach. The proposed propulsion method mimics the pectoral fins of a real fish. Pectoral fins of real fish are able to propel and change direction. We designed the propulsion mechanism of 1 D.O.F. that has two functions (propel and change direction). We named this propulsion system 'Flipper'. The proposed propulsion method can control forward, pitch and yaw motion using the Flipper. We made an experimental underwater robot system and verified the proposed propulsion method. We measured its maximum speed and turning motion using an experimental underwater robot system. We also analyzed the thrust force from the maximum speed, using the thrust equation. Experimental results showed that our propulsion method enabled the thrust system of the biomimetic robot.

• Journal of Ship and Ocean Technology
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• 제11권1호
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• pp.1-10
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• 2007

This study introduces the development of robot fish ROFI 1.1. Today, robot fish is one of strong candidates for next-generation UUV. The present paper describes the design, manufacturing, and operation tests of the robot fish developed at Seoul National University. The very first robot fish in Korea, ROFI 1.1 is operated by a wireless remote controller. Its overall length is 680mm, and weight is 8.8kg. The fore body contains main mechanical and electrical systems and is covered by a FRP skin. The aft body has a mechanical bone system that mimics fish bones, and its skin is made of flexible silicon sponge to allow elastic motion for propulsion. It is found that this mechanical system creates effective and realistic fish-like swimming mode. It is observed that the normal and maximum advancing speeds of ROFI 1.1 are about 1 and 2 m/sec, and the turning radius is between $0.7{\sim}2.5m$, depending on the turning mechanism.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.59.1-59.1
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• 2005

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.421-422
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• 2013

• 로봇학회논문지
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• 제5권3호
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• pp.197-208
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• 2010

The ostraciiform swimming mode allows the simplest mechanical design and control for underwater vehicle swimming. Propulsion is achieved via the flapping of caudal fin without the body undulatory motion. In this research, the propulsion of underwater vehicles by ostraciiform swimming mode is explored experimentally using an ostraciiform fish robot and some rigid caudal fins. The effects of caudal fin flapping frequency and amplitude on the cruising performance are studied in particular. A theoretical model of propulsion using rigid caudal fin is proposed and identified with the experimental data. An experimental method to obtain the drag coefficient and the added mass of the fish robot is also proposed.

• 한국전산유체공학회지
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• 제19권2호
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• pp.99-107
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• 2014

The aim of the present study is to investigate the flow interference between two adjacent undulating fish-like body, and its effect on the undulating propulsion. For this purpose, unsteady two dimensional incompressible flow calculations were conducted using an unstructured mesh flow solver, coupled with an overset mesh technique. To deal with mesh deformation due to fish locomotion, spring analogy is utilized. The fish body used in the simulation is constructed from the NACA0012 airfoil. The study indicates that the propulsion of undulating fish is proportional to frequency and wavelength of the midline oscillation when there is no adjacent fish. It also reveals that average thrust was increased when the vortex shedding from the tail was conserved well and pressure difference between upper and lower sides of the fish was magnified due to flow interference. From this study, which relative position and phase difference of locomotion between two fishes can generate maximum thrust was known among six different cases.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.321-322
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.489-490
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• 2008