• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.604-611
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• 2009

Modular snake-like robots are robust for failure and have flexible locomotion for environments, but are difficult to control. Various phase and evolutionary approaches for modular robots have been studied for many years, but there are few comparisons among these methods. In this paper, Phase, GAps, GA and GP approaches are implemented and compared for flat, stairs, and slope environments. In addition, simulations of the locomotion evolution for modular snake-like robot are executed in Webots environments.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 Proceedings International Workshop on New Video Media Technology
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• pp.13-17
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• 1996

This paper presents animation techniques and issues involved in virtual environments where the participants interact with each other through a network. The state of the participant should be recognized at each local site, and broadcast to the other sites. Because information exchange is minimal, animation techniques are applied to convert the incoming low DOF parameters into high DOF joint angles that completely determine the configuration of the agents at each frame. As a case study, a software system VRLOCO is introduced, which has been developed by the author over the last five years. From a simple stream of body center positions, VRLOCO generates realistic curved path human locomotion in real-time. Based on the heading direction and speed, the locomotion automatically switches among five different primitives: walking, running, lateral stepping, backward stepping, and turnaround. The techniques presented here proved robust and faithful: the algorithm is not sensitive to the noise in the data, and the resulting animation conforms well with the original data.

• 한국융합학회논문지
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• 제10권9호
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• pp.1-9
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• 2019

본 논문에서는 가상 환경(VE; Virtual Environment)에서 이동기술을 사용성평가 하기 위한 평가모델을 제안하고 사례연구를 통해 검증하고자 한다. 이를 위한 순서는 첫째, VR상에서 이동기술에 대한 이론적인 접근을 통해 분석하기 위한 요소를 도출한다. 둘째, VR상에서의 이동기술과 사용성 평가에 대한 정의 및 개념을 통해 이론적으로 정립하여 문헌조사를 통해 VE에 대한 이론적인 접근을 통해 분석하기 위한 요소를 도출한다. 셋째, 이를 바탕으로 VE에서의 이동기술을 평가하기 위한 사용성 평가 모델을 제안한다. 마지막으로, 문헌조사에서 도출한 세 가지 이동기술을 적용한 기존의 VR 게임을 실험 및 분석하여 결과를 도출한다. 본 논문을 통해 VR상에서의 이동기술은 각각의 방법을 별도로 사용하는 것이 아니라 사용성 평가를 통해 접근 및 분석하면 VR 게임 콘텐츠 성격에 부합하는 이동기술을 제안할 수 있다는 것을 알 수 있었다. 본 논문은 VR 콘텐츠의 제작 단계에서 이동기술의 문제점을 도출할 수 있고 기준을 제안할 수 있는 유의미한 자료라 사료된다.

• 로봇학회논문지
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• 제9권1호
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• pp.57-66
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• 2014

This paper describes the design concept of a bio-inspired legged underwater and estimating its performance by implementing simulations. Especially the leg structure of an underwater organism, diving beetles, is fully adopted to our designing to employ its efficiency for swimming. To make it possible for the robot to both walk and swim, the transformable kinematic model according to applications of the leg is proposed. To aid in the robot development and estimate swimming performance of the robot in advance, an underwater simulator has been constructed and an approximated model based on the developing robot was set up in the simulation. Furthermore, previous work that we have done, the swimming locomotion produced by a swimming patten generator based on the control parameters, is briefly mentioned in the paper and adopted to the simulation for extensive studies such as path planning and control techniques. Through the results, we established the strategy of leg joints which make the robot swim in the three dimensional space to reach effective controls.

• 한국컴퓨터그래픽스학회논문지
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• 제28권3호
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• pp.13-21
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• 2022

본 논문에서는 수직이동이 필요한 가상환경을 사용자가 이동할 때, 어떻게 카메라를 조작하는 것이 멀미를 최소화하면서도 몰입감을 극대화할 수 있는지를 조사하는 것이 목표이다. 일반적으로 사용자는 평평한 공간에서 가상현실을 이용하므로, 사용자의 실제 이동과 가상에서의 이동이 달라져 감각 충돌이 일어나게 되고, 이는 가상현실 멀미를 유발할 가능성을 가진다. 그러므로 3가지의 유력한 카메라 조작기법을 제안하고, 이들을 구현한 후, 사용자 실험을 통해 가장 적절한 모델이 어떤 것인지를 제안하고자 한다.

• Journal of Mechanical Science and Technology
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• 제19권10호
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• pp.1919-1931
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• 2005

Human joint motion can be kinematically described in three planes, typically the frontal, sagittal, and transverse, and related to experimentally measured data. The selection of reference systems is a prerequisite for accurate kinematic analysis and resulting development of the equations of motion. Moreover, the development of analysis techniques for the minimization of errors, due to skin movement or body deformation, during experiments involving human locomotion is a critically important step, without which accurate results in this type of experiment are an impossibility. The traditional kinematic analysis method is the Angular-based method (ABM), which utilizes the Euler angle or the Bryant angle. However, this analysis method tends to increase cumulative errors due to skin movement. Therefore, the objective of this study was to propose a new kinematic analysis method, Position-based method (PBM), which directly applies position displacement data to represent locomotion. The PBM presented here was designed to minimize cumulative errors via considerations of angle changes and translational motion between markers occurring due to skin movements. In order to verify the efficacy and accuracy of the developed PBM, the mean value of joint dislocation at the knee during one gait cycle and the pattern of three dimensional translation motion of the tibiofemoral joint at the knee, in both flexion and extension, were accessed via ABM and via new method, PBM, with a Local Reference system (LRS) and Segmental Reference system (SRS), and then the data were compared between the two techniques. Our results indicate that the proposed PBM resulted in improved accuracy in terms of motion analysis, as compared to ABM, with the LRS and SRS.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.119-123
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• 2006

The ionic-polymer-metal-composite actuators have the best merit for bio-mimetic locomotion because of their large bending performance. Especially, they have the advantage for mimicking a fish-like motion because IPMCs are useful to be actuated in water. So we have developed IPMC actuators with multiple electrodes for realization of biomimetic motion. Generally, the IPMC actuator has been fabricated in electroless plating technique, while it needs very long fabrication time and shows poor repeatability in the actuation performance owing to the variables in chemical fabrication process. Therefore, the novel fabrication methods were investigated by combining electroless plating and electroplating techniques capable of patterning precisely. On the whole, two different methods were compared and analyzed with similar thickness level of Platinum electrodes. Present results show that mixing chemical reduction and electroplating can be a promising candidate for electrode patterning.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.912-918
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• 2016

This paper presents various strategies for humanoid vehicle driving and egress tasks. For driving, a tele-operating system that controls a robot based on a human operator's commands is built. In addition, an autonomous assistant module is developed for the operator. Normal position control can result in severe damage to robots when they egress from vehicles. To prevent this problem, another approach that mixes various joint control techniques is adopted in this study. Additionally, a footplate is newly designed and attached to the vehicle floor for the ground landing phase of the egress task. The attached plate enables the robot to step down onto the ground in a safe manner. For stable locomotion, a balance controller is designed for the humanoid. For the design of the controller, the robot is modeled using an inverted pendulum that consists of a spring and a damper. Then, a state feedback controller (with pole placement and a state observer) is built based on the simplified model. Many approaches that are presented in this paper were successfully applied to a full-sized humanoid, DRC-HUBO+, in the DARPA Robotics Challenge Finals, which were held in the United States in 2015.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.718-721
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• 2007

The ionic-polymer-metal-composite actuators have the best merit for bio-mimetic locomotion because of their large bending performance. Especially, they have the advantage for mimicking a fish-like motion because IPMCs are useful to be actuated in water. So we have developed IPMC actuators with multiple electrodes for realization of biomimetic motion. This actuator is fabricated by combining electroless plating and electroplating techniques capable of patterning precisely and controlling a thickness of Pt electrode layer. The FRF analysis was conducted by a mechanical shaker and direct electrical excitation which is based on sweep sine wave function. From this result, the proper young‘s modulus of Platinum was investigated and applied on expecting the vibration characteristics of patterned IPMC actuator. The calculated maximum displacement of the patterned IPMC was 2.32mm under an applied 4mN/mm. The natural frequency was increased however displacement was decreased in according to increase a thickness of Pt.

• 한국가시화정보학회지
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• 제5권1호
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• pp.12-15
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• 2007

Macromolecule diffusion in cells and tissues is important for cell signaling, metabolism and locomotion. Biophysical methods, including non-invasive or minimally invasive in-vivo photobleaching techniques and single quantum-dot tracking, have been used to measure the rates of macromolecule diffusion in living cells and tissues, including central nervous system and tumors. Mathematical modeling and statistical analysis of experimental data revealed various modes of diffusion, which are strongly coupled with spatiotemporal changes in nanoscale structures and material properties.