• Structural Engineering and Mechanics
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• 제63권6호
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• pp.847-856
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• 2017

Excessive vibrations can occur in long-span structures such as floors or footbridges due to occupant?s daily activity like walking and cause a so-called vibration serviceability issue. Since 1970s, researchers have proposed many human walking load models, and some of them have even been adopted by major design guidelines. Despite their wide applications in structural vibration serviceability problems, differences between these models in predicting structural responses are not clear. This paper collects 19 popular walking load models and compares their effects on structure?s responses when subjected to the human walking loads. Model parameters are first compared among all these models including orders of components, dynamic load factors, phase angles and function forms. The responses of a single-degree-of-freedom system with various natural frequencies to the 19 load models are then calculated and compared in terms of peak values and root mean square values. Case studies on simulated structures and an existing long-span floor are further presented. Comparisons between predicted responses, guideline requirements and field measurements are conducted. All the results demonstrate that the differences among all the models are significant, indicating that in a practical design, choosing a proper walking load model is crucial for the structure?s vibration serviceability assessment.

• Journal of Computational Design and Engineering
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• 제3권3호
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• pp.250-265
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• 2016

Owing to our rapidly aging society, accessibility evaluation to enhance the ease and safety of access to indoor and outdoor environments for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Meanwhile, human behavior simulation has been progressing in the areas of crowd behavior analysis and emergency evacuation planning. However, in human behavior simulation, environment models represent only "as-planned" situations. In addition, a pedestrian model cannot generate the detailed articulated movements of various people of different ages and genders in the simulation. Therefore, the final goal of this research was to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM) with "as-is" environment models. To achieve this goal, we developed an algorithm for generating human-like DHM walking motions, adapting its strides, turning angles, and footprints to laser-scanned 3D as-is environments including slopes and stairs. The DHM motion was generated based only on a motion-capture (MoCap) data for flat walking. Our implementation constructed as-is 3D environment models from laser-scanned point clouds of real environments and enabled a DHM to walk autonomously in various environment models. The difference in joint angles between the DHM and MoCap data was evaluated. Demonstrations of our environment modeling and walking simulation in indoor and outdoor environments including corridors, slopes, and stairs are illustrated in this study.

• 한국항행학회논문지
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• 제21권1호
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• pp.132-137
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• 2017

본 논문에서는 로봇의 구조나 보행 상황을 반영해 하나의 보행 패턴을 다른 보행 패턴으로 변환하게 해주는 영모멘트 점 (ZMP; zero moment point)와 질량 중심 (CoM; center of mass)의 실시간 변환 방법을 제안한다. 일반적으로 휴머노이드 로봇은 높이와 질량과 같은 자체적인 구조 특성을 가지고 있다. 이러한 구조적 특성으로 인해 인간 또는 휴머노이드 로봇으로부터 측정되거나 생성되어진 CoM / ZMP 보행 패턴을 다른 로봇에 직접 적용하는 것은 어렵다. 이를 위하여 간단한 휴머노이드 로봇 모델인 cart-table model을 사용해 보폭의 길이, 보행 시간, CoM 높이 변화에 따라 보행 패턴의 특성을 분석한다. 그러한 분석으로부터 변환 방정식을 유도하고 시뮬레이션을 통해 제안된 방법을 검증한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.446-452
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• 2002

This paper Presents a 3-D design and a Vibration control of a new walking R.G.O.(Robotic Gait Orthosis) and would like to develop a simulation by this walking system. The vibration control and evaluation of the new knee joint mechanism on the biped walking R.G.O.(Robotic Gait Orthosis) was a very unique system and was to obtain by the 3-axis accelerometer with a low frequency vibration for the paraplegia It will be expect that the spinal cord injury patients are able to recover effectively by a biped walking R.G.O.. The new knee joint system of both legs were adopted with a good kinematic characteristics. It was designed attached a DC-srevo motor and controller, with a human wear type. It was able to accomodate itself to a environments of S.C.I. Patients. It will be expect that the spinal cord injury patients are able to recover effectively by a new walking R.G.O. system.

• 한국정밀공학회지
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• 제28권6호
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• pp.687-693
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• 2011

Spring-mass models have been widely accepted to explain the basic dynamics of human gait. Researchers found that the leg stiffness increased with gait speed to increase energy efficiency. However, the difference of leg stiffness change with gait speed between the young and the elderly has not been verified yet. In this study, we calculated the lower limb stiffness of the elderly using walking model with an axial spring. Vertical stiffness was defined as the ratio of the vertical force change to the vertical displacement change. Seven young and eight elderly subjects participated to the test. The subjects walked on a 12 meter long, 1 meter wide walkway at four different gait speeds, ranging from their self-selected speed to maximum speed randomly. Kinetic and kinematic data were collected using three force plates and motion capture cameras, respectively. The vertical stiffness of the two groups increased as a function of walking speed. Maximum walking speed of the elderly was slower than that of the young, yet the walking speed correlated well with the optimal stiffness that maximizes propulsion energy in both groups. The results may imply that human may use apparent limb stiffness to optimize energy based on spring-like leg mechanics.

• 제어로봇시스템학회논문지
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• 제8권8호
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• pp.665-672
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• 2002

This paper deals with the human-interactive actions of a quadruped robot by using Genetic Algorithm. In case we have to work out the designed plan under the special environments, our robot will be required to have walking capability, and patterns with legs, which are designed like gaits of insect, dog and human. Our quadruped robot (called SERO) is capable of not only the basic actions operated with sensors and actuators but also the various advanced actions including walking trajectories, which are generated by Genetic Algorithm. In this paper, the body and the controller structures are proposed and kinematics analysis are performed. All of the suggested motions of SERO are generated by PC simulation and implemented in real environment successfully.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권6호
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• pp.376-382
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• 2005

In this paper, practical biped humanoid robot is presented, designed, and modeled by fuzzy system. The humanoid robot is a popular research area in robotics because of the high adaptability of a walking robot in an unstructured environment. But owing to the lots of circumstances which have to be taken into account it is difficult to generate stable and natural walking motion in various environments. As a significant criterion for the stability of the walk, ZMP (zero moment point) has been used. If the ZMP during walking can be measured, it is possible for a biped humanoid robot to realize stable walking by a control method that makes use of the measured ZMP. In this study, measuring the ZMP trajectories in real time situations throughout the whole walking phase on the flat floor and slope are conducted. And the obtained ZMP data are modeled by fuzzy system to explain empirical laws of the humanoid robot. By the simulation results, the fuzzy system can be effectively used to model practical humanoid robot and the acquired trajectories will be applied to the humanoid robot for the human-like walking motions.

• 한국지능시스템학회논문지
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• 제24권5호
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• pp.477-481
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• 2014

인간은 다양한 감정을 가지고 있으며 매 시점의 감정 상태에 따라 사고와 판단, 행동이 영향을 받는다. 특히 어떤 사람의 보행하는 모습만 보아도 그 사람의 감정 상태를 짐작할 수 있을 정도로 보행 또한 감정에 영향을 받는다. 현재 휴머노이드 로봇의 이족보행에 관한 연구는 지면의 상태와 상관없이 안정하게 걷는 것을 주로 다루지만 인간과의 교감을 위해서는 감정상태에 따라 보행하는 패턴이 달라질 필요가 있다. 이를 위해 본 논문에서는 보행분석 시스템을 이용해서 네 가지 대표적인 감정(기쁨, 슬픔, 화남, 편안함) 상태에 있는 성인남녀의 보행 데이터를 취득 및 분석하고 상호 특성을 비교하는 연구를 수행했다. 본 논문에서 소개 된 정서적 보행 분석 내용은 휴머노이드 로봇의 정서적 보행에 참고 자료로 사용될 예정이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.85.2-85
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• 2002

If a biped humanoid robot walks stably on even and uneven planes like a human being, it should have a control system capable of compensating for moments generated by motions of its lower-limbs, upper-limbs and head. In this paper, a compensatory motion control method is described for the stability of biped humanoid robots. This control method calculates the combined motion of the trunk and the waist that cancels the generated moments by using an iteration algorithm. During the biped walking, the combined motion is employed only for stability while the motion of the lower-limbs is used only for locomotion. This method is useful for not only a steady walking but also a transient walking. The e...

• 한국전자통신학회논문지
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• 제9권10호
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• pp.1095-1102
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• 2014

본 논문에서는 실시간 감시 시스템에서 인간의 활동성을 분석하기 위하여 움직임 벡터를 사용하며, 고속연산에 GPU를 활용한다. 먼저 가장 중요한 부분인 전경으로부터 적응적 가우시안 혼합기법, 두드러진 움직임을 위한 가중치 차영상 기법, 움직임 벡터를 이용하여 인간이라고 판단되는 블랍을 검출하고, 추출된 움직임 벡터를 이용하여 사람의 활동성을 분석한다. 본 논문에서는 사람의 행동을 크게 {Active, Inactive}, {Position Moving, Fixed Moving}, {Walking, Running}의 세 가지 메타 클래스로 분류하고 인식하였다. 실험을 위해서 약 300개의 상황을 연출하였으며, 약 86%~98% 의 인식률을 보였다. 또한 $1920{\times}1080$ 크기 영상에서 CPU 기반은 4.2초 정도 걸렸는데, GPU 기반에서는 0.4초 이내로 빨라진 결과를 얻었다.