• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.306-314
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• 2009

The pelvis platform is the mechanical part which accomplishes the activities of diminishing the disturbances from the lower body and maintaining a balanced posture. When a biped robot walks, a lot of disturbances and irregular vibrations are generated and transmitted to the upper body. As there are some important machines and instruments in the upper body or head such as CPU, controller units, vision system, etc., the upper part should be isolated from disturbances or vibrations to functions properly and finally to improve the biped stability. This platform has 3 rotational degrees of freedom and is able to maintain balanced level by feedback control system. Some sensors are fused for more accurate estimation and the control system which integrates synchronization and active filtering is simulated on the virtual environment.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1312-1315
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• 1996

Polishing work for a curved surface die demands simple and repetitive operations and requires much time while it also demands high precision. Therefore it is operated by skilled worker in handiwork. But workers avoid polishing work gradually because of the poor environments such as dust and noise. In order to reduce the polishing time and to alleviate the problem of shortage of skilled workers, researches for automation of polishing have been pursued in the developed countries such as Japan. In this research we develop a polishing robot with 2 degrees of freedom motion and pneumatic system, and attach it to machining center with 3 degrees of freedom to form an automatic polishing system which keeps the polishing tool vertically on the surface of die and maintains constant pneumatic pressure. The developed polishing robot is controlled by real time sliding mode control using DSP(digital signal processor). A synchronization between machining center and polishing robot is accomplished by using M code of machining center. A performance experiment for polishing work is executed by the developed polishing robot.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.243-246
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• 2000

Productivty of tapping has been increasing through the tcchnological advances in synchronization between spindle rotation and feed motion even in the high spindle speed. However, not much researches have been conducted about tapping process because its complicate cutting mechanism. In order ta investigate the characteristics of the tapping process, this paper concentrates on the analysis of curting torque behavior during one cycle of lapping. As one completc thread is performed through the whole chamfer ercuttlng, cutting torque increases highly in chamfer cutting, but smaothly in full thread cutting Functioning of the threads guide. Cutting torque in backward cutting is smaller than in Sorwerd cutting due to only friction farce in against between the tool and workpiece. And torque behavior of a periodic Sine ripple-mark was identified during one revolution of a tap.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.743-747
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• 1997

Polishing work for a curved surface die demands simple and repetitive operations and requires much time while it also demands high precision. Therefore it is operated by skilled worker in handiwork. Howener workers avoid polishing work gradually because of the poor environments such as dust and noise. In order to reduce the polishing time and to alleviate the problem of shortage of skilled workers, researches for automation of polishing have been pursued in the developed countries. In the research, a polishing robot with 2 degrees of freedom motion attached to machining center with 3 degrees of freedom and pneumatic system forms an automatic polishing system which keeps the polishing tool vertically on the surface of die and maintains constant pneumatic pressure. A synchronization between machining center and polishing robot is accomplished by using M code of machining center. A rulled surface and shadow mask are polished by the developed polishing robot.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.138-140
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• 2014

The image quality of the color laser printer is highly related with the motion quality of actuators. However, the high precision system requires high production costs in general. The proposed design method in this paper improves image quality without increasing production costs. Using the synchronization method, time gap between exposure and transfer in organic photo conductive (OPC) drum and the period of driving gear revolution are synchronized. The proposed method is verified by computer simulations and experiment, and showed by printed images.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2415-2417
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• 2002

In this paper, we discuss about the real-time distributed system for the control of to motors using uCOS-II kernel. Real-time kernel needs to process the tasks for two motors in desired time to synchronize motion. We used both semaphore and message mail box for synchronization. In the previous study, we used step motors for the actuator of two axes robot, but could not draw a clear line because of motor resolution and synchronizing step pulse. To resolve the problem we rebuilt the transfer robot with DC motors and the dedicated position servor which had built in out lab. Moreover we developed the PC based graphic user interface for generating planar drawing image control. Experimental results also presented to show the proposed control system is useful.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.3
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• pp.182-187
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• 2004

In this paper, we propose a PC based distributed controller for a two axis convey table using real-time micro-kernel. PC, Windows program, gives an easy way to implement wealthy GUI and micro-kernel, ${\mu}$C/OS-II, provides a real-time capability to control devices. We built a real-time distributed control system using ${\mu}$C/OS-II kernel which needs to process the tasks for two motors within the desired time to synchronize the motion. We used both semaphore and message mail box for synchronization. Unlike the previous study where we used step motors for the actuator of two axes convey table, we rebuilt the convey table with DC motors and the dedicated position servo which had built in out lab, and then we implemented a realtime distributed control system by putting the micro-kernel into between PC and position servo. Moreover we developed the PC based graphic user interfaces for generating planar drawing image control. Experimental results also presented to show the Proposed control system is useful.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1435-1440
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• 2017

Recently, VR and AR are emerging as an area of interest in ICT. In virtual reality to feel like a real, many people are looking for them because of its charm. However, the motion of the VR image and the moving object are not synchronized exactly, and a problem of feeling nausea is also occurring. The problem should be solved by the application of Attraction in the VR system. In this paper, we propose a module that minimizes delay time by synchronizing movement of VR image and moving object. The proposed module calculates the moving distance using the direction and the acceleration sensor that the user views through the VR device. The module proposed in this paper will pay attention to the fact that the movement of the attraction moves along a fixed path, so that the accurate travel distance can be calculated.

• Journal of the Korea Computer Graphics Society
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• v.26 no.4
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• pp.9-15
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• 2020

Having a virtual talking face along with a virtual body increases immersion in VR applications. As virtual reality (VR) techniques develop, various applications are increasing including multi-user social networking and education applications that involve talking avatars. Due to a lack of sensory information for full face and body motion capture in consumer-grade VR, most VR applications do not show a synced talking face and body. We propose a novel method, targeted for VR applications, for talking face synced with audio with an upper-body inverse kinematics. Our system presents a mirrored avatar of a user himself in single-user applications. We implement the mirroring in a single user environment and by visualizing a synced conversational partner in multi-user environment. We found that a realistic talking face avatar is more influential than an un-synced talking avatar or an invisible avatar.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.136-143
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• 2018

Recently, with the rapid development of virtual reality technology, there have been more and more applications of virtual reality technology in various fields. In order to realize a virtual reality, a method of implementing a visualization environment through an HMD (Head Mounted Display) is widely used. However, in the current visualization environment through the HMD, the user feels dizziness when worn, It has the disadvantage of imposing restrictions on. In this study, it is aimed to realize virtual reality visualization environment through multi-screen environment which improves the experience effect of virtual environment by using existing screen instead of visualization through HMD, and compensates for shortcomings of HMD method. In order to realize a multi-screen environment as a highly visualized environment, a technique for matching the spatial position of the multi-screen with the spatial position of the virtual environment is required. To do this, we need an efficient method to precisely measure the position of the space, and we propose a spatial position compensation methodology that can efficiently and precisely measure the position of the real space and reflect it in the virtual environment.