• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.18 no.5
• /
• pp.521-528
• /
• 2009

In these days, biomimetic apprioach in the design and control of robotic system has drawn much attention. The human-being and mammals possess their own feet. Using the mobility of their feet, they are able to walk in various environments such as plain land, desert, swamp, and so on. Previously developed biped robots and four-legged robots did not employ such adaptable foot. In this work, a biomimetic foot mechanism is investigated through analysis of the foot structure of the human-being. This foot mechanism consists of a toe, an ankle, a heel, and some springs replacing the foot muscles and tendons. Using five toes and springs, this foot can adapt to various environments. A mathematical modeling for this foot mechanism was performed and its characteristics were observed through numerical simulation.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2014.11a
• /
• pp.913-916
• /
• 2014

본 논문의 수중로봇 도미(Domi) ver1.0는 관상어용 물고기 로봇 개발을 목표로 연구 개발되었다. 물고기 로봇은 머리, 1단, 2단 몸체와 꼬리부분과 2개의 구동 관절로 구성되어 있다. 물고기 로봇의 추력에 적합한 구동부 선정을 위하여 물고기 로봇 모델링과 유영 해석을 통하여 관절 구동부가 설계되었다. 또한 물고기 로봇의 유영알고리즘은 Lighthill 운동학 해석을 기초로 생체 모방의 유영 근사화 방법을 적용하였다. 설계된 물고기는 수동유영 및 자율운영모드로 동작된다. 수동유영모드는 RF 송수신에 의하여 구현된다. 본 설계된 물고기로봇 도미 ver1.0은 수중 현장시험 평가을 통하여 추력, 내구성, 방수성 등의 성능이 우수함을 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.11
• /
• pp.1741-1747
• /
• 2010

This work presents a study on the design of an economic service robot hand for tele-presence manipulators. The conceptual design of new robot hand is derived from biomimetics approach. Guided by the analysis of human arm' musculoskeletal structure, the fingers are actuated by cables and actuators in the forearm. High tension in the cables is achieved by screw-nut mechanism driven by DC motors. A set of combination springs is incorporated in each of the screw-nut mechanism for easy control of gripping force. The first prototype revealed difficulties with finger control and coupling problem between gripping force and wrist movement. The solutions to these problems have been derived from the contradiction analysis of TRIZ. The second design has been verified by tests on various objects with different weight and shape for full range of wrist motion.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.6
• /
• pp.404-411
• /
• 2018

This paper proposes a dolphin whistle mimicking underwater communication method using FSK (Frequency Shift Keying) and method to improve BER (Bit Error Rate) performance by using multipath gain combining. The proposed method divides whistle sound into short time intervals and transmits FSK modulated signal that ensures orthogonality of the symbol. Multipath gain can be obtained by using characteristic of mimicked signal frequency that varies with time. To demonstrate the performance of the proposed method, computer simulations and lake experiments were conducted. Computer simulation results show that an additional multipath gain is obtained by multipath. From lake experiments, when symbol length is 20 msec and modulation band is 900 Hz, the proposed FSK method with multipath combining gain obtains BER of 0.002, which is better than CSS (Chirp Spread Spectrum) with BER of 0.185. he proposed based on FSK method has higher imitation degree than the CSS method by analyzing mean cross-correlation value in the time - frequency domain of the imitated signal and actual whistle signal.

• ICROS
• /
• v.18 no.1
• /
• pp.36-41
• /
• 2012

박쥐는 초음파를 사용하여 획득한 정보를 바탕으로 집을 찾거나 먹이를 잡는 등의 복잡한 임무를 수행한다는 것을 보았을 때 박쥐의 초음파 시스템은 현재 우리가 사용하고 있는 기술보다 뛰어나다고 볼 수 있다. 따라서 박쥐의 초음파 시스템에 대한 연구를 바탕으로 공기 중에서의 초음파 기술에 적용하여 성능을 향상시킬 수 있을 것이다.

• The Journal of the Acoustical Society of Korea
• /
• v.40 no.3
• /
• pp.219-227
• /
• 2021

This paper proposed an Orthogonal Frequency Division Multiplexing (OFDM) based biomimetic communication method using a dolphin whistle which covertly transmits communication signals to allies. The proposed method divides the dolphin whistle into several time slots corresponding to a number of OFDM symbols, and modulates the communication signal by mapping differential phase shift keying (DPSK) symbols into subcarriers that have the frequency bands of the dolphin whistle in each slot. The advantages of the proposed method are as follows: In the conventional Chirp Spread Spectrum (CSS) and Frequency Shift Keying (FSK) based biomimetic communication methods, the discontinuity of the frequency contour is large, but the proposed method can reduce the discontinuity. Even if the modulation order is increased, the degradation of the mimicking performance is small. The computer simulations demonstrate that the Bit Error Rate (BER) and mimicking performance of the proposed method are better performance than those of the conventional CSS and FSK.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.3
• /
• pp.108-113
• /
• 2005

Biomimetic actuators that can produce soft-actuation but large force capability are of interest. Nafion, an effective ionomeric material from DuPont, has been shown to produce large deformation under low electric fields (<10V/mm). Carbon nanotube/polymer nanocomposites were cast to enhance the electromechanical properties of the composites. Multiwalled carbon nanotube (M-CNT)/Nafion nanocomposites were prepared by a solution casting to investigate the effect of M-CNT loading in the range of 0 to 7 wt% on electromechanical properties of the M-CNT/Nafion nanocomposites. The measured elastic modulus and actuation force of the M-CNT/Nafion nanocomposites are drastically different, showing larger elastic modulus and improved electromechanical coupling, from the one without M-CNT.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.8
• /
• pp.662-669
• /
• 2012

The effect of aspect ratio (AR) on the aerodynamic characteristics of a flapping wing was examined to analyze the design parameters of an insect-based MAV. The experimental model constructed with 4-bar linkages was operated in a water tank with the condition of a low Reynolds number. A water-proof micro-force load cell was fabricated and installed at the root of the wing which is made of a plexiglas. The wing shapes were based on the planform of a fruit fly wing. The ARs selected were 1.87, 3.74 and 7.48 and the Reynolds number was fixed at $10^4$. For AR=1.87 and 3.74, distinct lift peaks which indicate unsteady effects such as 'wake-capture' were observed at the moment of the start of the wing-stroke. However, for AR=7.48, no unsteady effects were observed. These phenomena were also observed in the delayed rotation case. The results indicate that a larger AR provides better aerodynamic performance for the insect-based flapping wing which can be applied in MAV designs.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.19 no.1
• /
• pp.19-24
• /
• 2009

The purpose of this study was to investigate the formation of apatite layer on two different titanium substrate treated with biomimetic method, Titanium plates were heat-treated at different temperatures of $400^{\circ}C$, $600^{\circ}C$, and $800^{\circ}C$ for 5 h in air atmosphere, And then, that plates were chemically treated with an alkali solution of 1 M sodium hydroxide (NaOH), The pre-treated titanium plates were soaked in the simulated body fluid (SBF) of Kokubo's recipe, After soaking for 7 days and 21 days in SBF, the coated layers formed on the titanium plates were characterized and compared with the morphology and chemical composition, The apatite formation was more activated on the titanium plates chemically treated with NaOH compared with the only heat-treated titanium plates.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.3
• /
• pp.1-5
• /
• 2006

Birds and insect in nature morph their mean camberline shapes to obtain both lift and thrust simultaneously. Previous unsteady thin airfoil theories were derived mainly for a rigid flapping airfoil. An extended unsteady thin airfoil theory for a deformable airfoil is required to analyze the unsteady two-dimensional aerodynamic characteristics of a biomorphing wing. Theodorsen's approach is extended to calculate the unsteady aerodynamic characteristics of a biomorphing airfoil. The mean camberline of the airfoil is represented as a polynomial. The unsteady aerodynamic characteristics of the morphing airfoil are represented as noncirculatory and circulatory terms. Present theory can be applied to the unsteady aerodynamic analysis of a flapping biomorphing airfoil and the aeroelastic analysis of a morphing wing.