• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3092-3094
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• 1999

This paper deals with the gait generation of Biped Walking Robot (IWR-III) to have a continuous walking pattern like human. For this, trajectory planning with the consideration of kick action is done in each walking step, and the coordinate transformation is done for simplifying the kinematics. The trunk moves continuously for all walking time and moves toward Z-axis. Balancing motion is acquired by FDM(Finite Difference Method) during the walking. By combining 4-types of pre-defined steps, multi-step walking is done. Using numerical simulator, dynamic analysis and system stability is confirmed. Walking motion is visualized by 3D-Graphic simulator. As a result, the motion of balancing joints can be reduced by the trunk ahead effect during kick action, and impactless smooth walking is implemented by the experiment.

• The Journal of Korea Robotics Society
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• v.16 no.2
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• pp.86-93
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• 2021

This paper proposes a controller to regulate the supply pressure of the hydraulic power unit (HPU) for driving a bipedal robot. We establish flow rate models for charging accumulator, actuating joints and leaking from actuators and spool valves. This determines the pump driving motor speed to satisfy the demanded flow rate for operating the bipedal robot without the energy loss caused by the bypass through a pressure regulating valve. We apply proposed controller to an onboard HPU mounted on top of bipedal robot platform with twelve degrees of freedom. We implement air-walking motion and squat motion which require variable flow rate to the bipedal robot. Through this experiment, the energy efficiency of proposed controller was verified by comparing the electric energy consumed when the controller was applied and when the pump operated at constant speed. We also shows the capability of the HPU's control performance to regulate supply pressure.

• The Journal of Korea Robotics Society
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• v.16 no.2
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• pp.147-154
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• 2021

One of the most challenging issues when robots interact with the environment is to establish contact quickly and avoid high impact force at the same time. The proposed method implements the passive suspension system using the redundancy of the torque-controlled robot. Instead of utilizing the actual mechanical compliance, the distal joints near the end-effector are controlled to act as a virtual spring-damper system with low feedback gains. The proximal joints are precisely controlled to push the mid-link, which is defined as the boundary link between the proximal and distal joints, towards the environment with high feedback gains. Compared to the active compliance methods, the contact force measurements or estimates are not required for contact establishment and the control time delay problems do not occur correspondingly. The proposed method was applied to the landing foot control of the 12-DoF biped robot DYROS-RED in the simulations. In the results, the impact force during landing was significantly reduced at the same collision speed.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.241-250
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• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.223-231
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• 2014

Humanoid robot is the most suitable robot platform for effective human interaction and various intelligent services. The present work addresses development of real time wireless control application of humanoid robot's forward and backward walks, and turning in walking. For convenience of human users, the application is developed on Android OS (Operating System) working on his or her smartphone. To this end, theoretic background on various-directional biped walking is proposed based on joint trajectories for forward walking, which have been shaped with a global optimization method. In this paper, backward walking is scheduled by interchange of angles and angular velocities and additional change of signs in angular velocities at all the via-points connecting cubic polynomial trajectories. Turning direction in walking is also implemented by activating the transversal hip joint initially located in the support leg in two stages. After validation of the proposed walking schemes with Matlab simulator, a smartphone application for the omnidirectional walking has been developed to control a humanoid robot platform named DARwIn-OP interconnected via Wi-Fi. Experiment result of the present wireless control of a humanoid robot with smartphone is successful, and the application will be released in application market near future.

• Journal of the Korean Society of Costume
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• v.39
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• pp.59-77
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• 1998

This paper is focused on the traditional sash weaving handicraft of‘She’ethnic group, which is located in Fujian, Zhejiang, Jiangxi, Guangdong province of China. This research is main-ly based on the field work, analyzed and inter-preted the traditional sash in systematic and reasoned way. The summary of this study are as follows : 1. On its technological aspect, weaving structure of the traditional sash is made of warp rod backed weaving. The used tool is primitive one but the weaving process includes scientific method. 2. From the social-cultural point of view, the sash ha been the symbol of love towards her lover. Every woman of this group had taken training for this sash weaving from a child. 3. On its ethnological aspect, it has been long history and has interchanged with other ethnic group like Miao, Han and also Okinawa country of Japan. The pattern inside this sash are almost looks like characters, but they are not Chinese characters whereas are the inde-pendent code of‘She’ group and have been inherent from ancestors and which will be tran-smitted to their posterity. These independent code of‘She’group are the traditional message to their later generation implicating their natural circumstances, human relationship, ethnic myth, spirit etc. 4. I recognize that the pattern inside the sash is defined as the communicative code and in comparison to language, it is more repetition and less apparent as close code. Nowadays China has been developed es-pecially in the economical fields rapidly. Under the circumstances traditional weaving culture of ethnic groups has been facing a crisis of disappearance, which will be a great loss for the country as well as the human beings. For this reason, I emphasize that it is very immediate to make co-researches into the material culture of Chinese ethnic groups.

• Journal of the Korea Computer Graphics Society
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• v.25 no.3
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• pp.133-142
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• 2019

In physics-based character animation, trajectory optimization has been widely adopted for automatic motion synthesis, through the prediction of an optimal sequence of future states of the character based on its system dynamics model. In general, the system dynamics model is neither in a closed form nor differentiable when it handles the contact dynamics between a character and the environment with rigid body collisions. Employing smoothed contact dynamics, researchers have suggested efficient trajectory optimization techniques based on numerical differentiation of the resulting system dynamics. However, the numerical derivative of the system dynamics model could be inaccurate unlike its analytical counterpart, which may affect the stability of trajectory optimization. In this paper, we propose a novel method to derive the closed-form derivative for the system dynamics by properly approximating the contact model. Based on the resulting derivatives of the system dynamics model, we also present a model predictive control (MPC)-based motion synthesis framework to robustly control the motion of a biped character according to on-line user input without any example motion data.

• Journal of Korea Entertainment Industry Association
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• v.8 no.2
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• pp.283-297
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• 2014

The future of human life is expected to be innovative by increasing social, economic, political and personal, including all areas of life across the multi-disciplinary skills. Particularly, in the field of robotics and next-generation games with robots, by multidisciplinary contributions and interaction, convergence between technology is expected to accelerate more and more. The purpose of this study is that by new interface model beyond the technical limitations of the "human-robot interface technology," until now and time and spatial constraints and through fusion of various modalities which existing human-robot interface technologies can't have, the research of more reliable and easy free "human-robot interface technology". This is the research of robot game system which develop and utilizing real time synchronization engine linking between biped humanoid robot and the behavior of the position value of mobile device screen's 3D content (contents), robot (virtual robots), the wireless protocol for sending and receiving (Protocol) mutual information and development of a teaching program of "Direct Teaching & Play" by the study for effective teaching.