• Journal of Drive and Control
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• v.15 no.3
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• pp.1-7
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• 2018

Humanoid robots have fascinated many researchers since they appeared decades ago. For the requirement of both accurate tracking control and the safety of physical human-robot interaction, torque control is basically desirable for humanoid robots. Humanoid robots are highly nonlinear, coupled, complex systems, accordingly the calculation of robot model is difficult and even impossible if precise model of the humanoid robots are unknown. Therefore, it is difficult to control using traditional model-based techniques. To realize model-free torque control, time-delay control (TDC) for humanoid robot was proposed with time-delay estimation technique. Using optimal walking trajectory obtained by particle swarm optimization, TDC with proposed scheme is implemented on whole body of a humanoid, not on biped legs even though it is performed by a virtual humanoid robot. The simulation results show the validity of the proposed TDC for humanoid robots.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2217-2220
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• 2005

This paper introduces a practical implementation of virtual crowd simulation software. Usual commercial crowd simulation softwares are complex and have program-like script interfaces, which makes an animator hard to learn and use them. Based on the observations that most crowd scenes include walking, running and fighting movements, we have implemented a crowd simulation system that automatically generates movements of virtual characters given user's minimal direction of initial configuration. The system was implemented as a plug-in of Maya which is one of the most commonly used 3D software for movies. Because generated movements are based on optically captured motion clips, the results are sufficiently natural.

• Journal of Korean Physical Therapy Science
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• v.24 no.3
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• pp.1-11
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• 2017

Purpose: The purpose of this study was to investigate the effects of virtual reality based treadmill training on muscle architecture of gastrocnemius in chronic stroke patients. Methods: Thirty chronic stroke patients were randomly assigned to either the virtual reality based treadmill training (VRTT) group (n=15) or treadmill training (TT) group (n=15). Both groups participated in a standard rehabilitation program; in addition, the VRTT group participated in virtual reality based treadmill training for 30 minutes per day, three times per week, for 6 weeks, and TT group participated in treadmill walking training for 30 minutes per day, three times per week, for 6 weeks. Ultrasound image was used for measurement of pennation angle and muscle thickness of the medial gastrocnemius muscle at rest and during maximum voluntary contraction. Results: In the paretic side medial gastrocnemius muscle, greater improvement on the pennation angle and muscle thickness while resting and maximal voluntary contraction were observed in the VRTT group compared with the TT group. Conclusion: Findings of this study demonstrated that the virtual reality based treadmill training has an effect on muscle architecture of medial gastrocnemius in chronic stroke patients.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.17-28
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• 2021

The purpose of the research was to examine the effect of field of view on egocentric distance perception in the real and virtual environment. The replica that mimicked the real environment condition was used to create the virtual environment condition. We manipulated field of view levels equally in both viewing conditions using glasses that limit the field of view in real-world conditions and limiting the field of view in virtual-world conditions in a manner equivalent to real-world conditions via HMD. Eighteen participants observed the target with a limited field of view in a real and virtual environment without head movement. Then, we measured perceived distance using the timed imagined walking method, which measures the time taken by each participant to mentally walk to the target. The target was shown three times at three different distances from the participants: 3, 4, and 5 m. For the analysis, we converted time estimates into distance estimates. Consequently, the estimated distance in the virtual environment condition was less than the estimated distance in the real environment condition. And as the field of view shrank, the estimated distance also decreased. The estimated distance did not vary with field of view levels in real-world conditions. In the virtual environment, the estimated distance decreased as the field of view decreased, whereas in the real environment, the estimated distance increased. The implications of the results and some future research directions are discussed below.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.202-208
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• 2020

Body balance necessary for ordinary daily activities can be undermined by diverse causes. In this study, as a way to control such a problem, we have produced smart insole as a wearable device in the form of insole and developed analysis software evaluating body balance, which measures ground reaction force applied to each area of sole and Center of Pressure (COP). The software visualized changes in COP positions while a user was moving and average COP positions, and it is also capable of measuring the COP values in the Anterior-Posterior (AP) and Medial-Lateral (ML) areas of feet. Through gait analysis, it can analyze the time of walking, strides, speed, COP trajectory while walking, etc. In addition, we have developed training contents for body balance improvement designed in consideration of Y-Balance Test and Timed Up and Go (TUG) Test. They were established in virtual reality similar to daily living environment so that people can expect more effective training results regardless of places.

• Journal of Fashion Business
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• v.14 no.4
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• pp.161-173
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• 2010

This study aims to examine for efficient production methods of custom-tailored clothing and application of 3D virtual clothing system in custom-tailored clothing market, by producing and analyzing both real clothing and 3D virtual clothing. For this study, a middle-aged woman is selected as the subject figure and one-piece is selected as the experimental clothes item. In real clothing, I conducted the wearing evaluation for experts and the subject figure. And In the virtual clothing, I conducted the wearing evaluation with i-Designer using 3D virtual clothing on simulation program. There are some differences between the data from body scanning and the real body size. In the custom-tailored clothing market in which the fitness is important, the research which measures the more exact data is needed. And in the case of complicate design, the functions which measure the activity and the fitness variously and correct the parts of curves are needed. This study experiments the availability of application of 3D Virtual Clothing System in custom-tailored clothing market by selecting one-piece as the experimental clothes item. So the follow-up studies for the other designs and fabrics are needed. Also, if the studies for checking the clothes pressure, the amount of composure, the space between skin and clothing when the virtual model wearing clothes is walking or shaking his arms are proceeding, then 3D virtual clothing System is applicable in custom-tailored clothing market. But there are some restrictions and lack of education in virtual clothing System yet, and it makes hard for workers in clothing market to use it in real production. However, 3D virtual clothing System will be practical in real market if there would be more research on its usability and practicality, and workers in clothing market can be easily educated on techniques of 3D virtual clothing system.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.04a
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• pp.262-267
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• 1998

A hierarchical motion control system for animation of 3D human character is implemented using the motion database in realtime. The proposed motion control system consists of coordination controller for gait timing and balancing of walking motion, joint servo controller for realistic limb movement, and motion database for goal-directed character animation which makes time-consuming animation relatively easy task. As one example among the various applications of the proposed motion control system. We present a simple virtual reality system in which the motion control system plays a central role in generating realistic motion of virtual human character.

• The Journal of Korea Robotics Society
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• v.2 no.3
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• pp.242-248
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• 2007

Robot system development consists of several sub-tasks such as layout design, motion planing, and sensor programming etc. In general, on-line programming and debugging for such tasks demands burdensome time and labor costs, which motivates an off-line graphic simulation system. MSRS(Microsoft Robotics Studio) released in recent years is an appropriate tool for the graphic simulation system since it supports CCR(Concurrency and Coordination Runtime), DSS(Decentralized System Services), and dynamics simulation based on PhysX and graphic animation as well. In this paper, we developed an MSRS based network simulation system for quadruped walking robots, which controls virtual 3D graphic robots existing in remote side through internet.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.315-322
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• 2009

This paper explains a control and navigation algorithm of a 6-DOF gait rehabilitation robot, which can allow a patient to navigate in virtual reality (VR) by upper and lower limbs interactions. In gait rehabilitation robots, one of the important concerns is not only to follow the robot motions passively, but also to allow the patient to walk by his/her intention. Thus, this robot allows automatic walking velocity update by estimating interaction torques between the human and the upper limb device, and synchronizing the upper limb device to the lower limb device. In addition, the upper limb device acts as a user-friendly input device for navigating in virtual reality. By pushing the switches located at the right and left handles of the upper limb device, a patient is able to do turning motions during navigation in virtual reality. Through experimental results of a healthy subject, we showed that rehabilitation training can be more effectively combined to virtual environments with upper and lower limb connections. The suggested navigation scheme for gait rehabilitation robot will allow various and effective rehabilitation training modes.

• Journal of Computational Design and Engineering
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• v.3 no.3
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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.