• The Journal of Korea Robotics Society
• /
• v.4 no.2
• /
• pp.88-96
• /
• 2009

In this paper, we present a linear controller for attitude of aircraft. We use a rotational matrix in one approach and a quaternion in the other approach. We also find some interesting mathematical properties concerning a symmetric rotational matrix and we use these properties to analyze the stability of the proposed control law. We find that the quaternion approach is better than rotational matrix approach because there exists no singular region problem in quaternion approach. On the other hand, singular region problem may happens in rotational matrix approach. The controller structure of the quaternion is also very simple compared with the one proposed by using a rotational matrix approach. We make use Matlab Simulink to simulate and illustrate the theoretical claims. The graphic animation program is developed based on Open-GL for the computer simulation of the proposed control algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.346-349
• /
• 1995

In this paperwe develop a real-time simulator for direct drive cooperative robot by using OpenGL in a Windows NT based system. This simulator is composed of 2 parts, a display part and an interface part. In the display part the robot is modelled and rendered in 3D space. To do this OpenGL, a kind of graphic library, is used for rendering and animating robots and kinematics gives the information of the current robot configuration. The control and the feedback data are sent and received via the interface part. In real time simulation interfacing part needs fast data transfer rate and good nosic immunity. In experiment we have simulated 2-link direct drive cooperative robots using the trajectory tracking algorithm proposed in reference.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.04a
• /
• pp.229-233
• /
• 2001

In this paper, we propose a remote controller for robot manipulator using local area network(LAN) and internet. To do this, we develope a server-client system as used in the network field. The client system is in any computer in remote place for the user to log-in the server and manage the remote factory. the server system is a computer which controls the manipulator and waits for a access from client. The server system consists of several control algorithms which is needed to drive the manipulator and networking system to transfer images that shows states of the work place, and to receive a Tmp data to run the manipulator. The client system consists of 3D(dimension) graphic user interface for teaching and off-line task like simulation, external hardware interface which makes it easier for the user to teach. Using this server-client system, the user who is on remote place can edit the work schedule of manipulator, then run the machine after it is transferred and monitor the results of the task.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.4
• /
• pp.173-179
• /
• 2003

In this paper, a real-time multibody vehicle dynamics and control model has been developed for a virtual reality intelligent vehicle simulator. The simulator consists of low PCs for a virtual reality visualization system, vehicle dynamics and control analysis system a control loading system, and a network monitoring system. Virtual environment is created by 3D Studio Max graphic tool and OpenGVS real-time rendering library. A real-time vehicle dynamics and control model consists of a control module based on the sliding mode control for adaptive cruise control and a real-time multibody vehicle dynamics module based on the subsystem synthesis method. To verify the real-time capability of the model, cut-in, cut-out simulations have been carried out.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.1 s.232
• /
• pp.96-106
• /
• 2005

An integrated single-wafer processing tool, composed of multiple single wafer processing modules, transfer robots, and load locks, has complex routing sequences, and often has critical post-processing residency constraints. Scheduling of these tools is an intricate problem, and testing schedulers with actual tools requires too much time and cost. The Single Wafer Processor (SWP) simulator presented in this paper is to validate an on-line scheduler, and evaluate performance of integrated single-wafer processing tools before the scheduler is actually deployed into real systems. The data transfer between the scheduler and the simulator is carried out with TCP/IP communication using messages and files. The developed simulator consists of six modules, i.e., GUI (Graphic User Interface), emulators, execution system, module managers, analyzer, and 3D animator. The overall framework is built using Microsoft Visual C++, and the animator is embodied using OpenGL API (Application Programming Interface).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.2
• /
• pp.1426-1433
• /
• 2015

CCTV-applied monitoring is an effective measure to suppress potential crimes and record objective relationship; however, there is no methodology that can quantitatively compare and assess the afore-mentioned effects. Thus, this study intended to construct the methodology and analysis application that can measure the changes in the space-corresponding performance of CCTVs depending on installation measures by using 3-dimenstional virtual simulation technology. For analysis, the raster-based Isovist theory was 3-dimensionally expanded and the amount of incident sight line to each point was accumulated. At the same time, the amount of overlapped monitoring in the CCTV cameras that were connected to each measurement node was accumulated for cross-analysis. By applying the examples and analyzing the results, it was possible to construct an analysis application in use of collision detection model and quantify the changes of monitoring performance depending on positioning alternative of the cameras. Moreover, it enabled intuitive review and supplementation by reproducing visible shadow areas in a graph.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.11
• /
• pp.101-109
• /
• 2009

Generally, depth cache and pixel cache of 3D graphics are designed by using write-back scheme for efficient use of memory bandwidth. Also, there are write after read operations of same address or only write operations are occurred frequently in 3D graphics cache. If a cache miss is detected, an access to the external memory for write back operation and another access to the memory for handling the cache miss are operated simultaneously. So on frequent cache miss situations, as the memory access bandwidth limited, the access time of the external memory will be increased due to memory bottleneck problem. As a result, the total performance of the processor or the IP will be decreased, also the problem will increase peak power consumption. So in this paper, we proposed a novel early write back cache architecture so as to solve the problems issued above. The proposed architecture controls the point when to access the external memory as to copy the valid data block. And this architecture can improve the cache performance with same hit ratio and same capacity cache. As a result, the proposed architecture can solve the memory bottleneck problem by preventing intensive memory accesses. We have evaluated the new proposed architecture on 3D graphics z cache and pixel cache on a SoC environment where ARM11, 3D graphic accelerator and various IPs are embedded. The simulation results indicated that there were maximum 75% of performance increase when using various simulation vectors.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.372-372
• /
• 2022

스마트시티 하천관리를 위해 선행된 연구에서는 도시하천관련 데이터를 수집-정제-제공하는 도시하천 통합데이터 플랫폼을 개발하였다. 이에 하천 분석을 위한 유역 유출, 하천 흐름 그리고 도시유출 등의 모듈과 하천 환경, 친수, 종합 평가 모델을 연계하여 도시하천관리 연계플랫폼으로 연구개발을 진행하였다. 본 연구에서는 스마트시티 하천관리를 위한 시나리오 기반 제방 파제 시뮬레이션 분석 결과 가시화 모듈에 관한 연구를 진행한다. 부산 EDC 지역을 대상으로 DEM, 항공영상, 위성영상, 하천 지리 정보, 하천 단면도 등의 데이터를 결합하여 하천 및 유역 전산 3D 형상 모델링을 진행한다. 또한 하천 내부 유량 및 파제 제체 모델링, 유동장 격자 모델링을 통해 제방 붕괴 범람 시뮬레이션 대상 지역을 구현한다. 해당 EDC 지역 구현 모델에 연속방정식, 운동량방정식, 수송방정식 등 지배방정식과 삼상 유동 기법 등 수치 해석 기법을 활용하여 제방 파제 시뮬레이션을 수행한다. 시뮬레이션의 침수범위 및 침수심 분포 결과는 위경도를 포함한 ASCII Grid로 반환되며 GeoServer를 통한 좌표계 설정 및 도시하천 연계플랫폼에서 가시화하는 연구를 진행하였다. 제방 파제 시나리오는 제방 높이 2m, 제방 폭 7.5m, 파제 길이 20m로 설정하여 4개의 붕괴 위치를 지정하였고, 지정된 위치에 대한 제방 파제 3D 시뮬레이션을 통해 도출된 Case 별 2D/3D 영상과 침수심 공간 분포에 대한 Raster Graphics를 전처리하여 시나리오별 침수범위-침수심을 도시하천 연계플랫폼 상에서 가시화하는 연구를 진행하였다. 도시하천 연계플랫폼의 시나리오 기반 제방 파제 시뮬레이션 모듈을 통하여 스마트시티의 제방 파제 피해 양상 및 대책 마련 의사결정 보조로 활용할 수 있을 것으로 기대된다.

• Journal of Astronomy and Space Sciences
• /
• v.15 no.2
• /
• pp.427-436
• /
• 1998

The apogee manoeuvre of $KOREASAT-1{cdot}2{cdot}3$ is basic elliptical orbit transfer converting orbit plane. The KOREASAT-3 is planed for multi-burn manoeuvres using the liquid apogee engine while the $KOREASAT-1{cdot}2$ used the apogee kick motor that executes a single burn in the apogee of transfer orbit using the solid propellant. This study analyzed the multi-burn manoeuvres using the liquid apogee engine and the propellant control method and developed the simulation tools. For the purpose of precise simulation, We designed tools in the basic of orbit propagation software, COWELL5, that was developed by members of Center for Astrodynamics in Yonsei university and the results can be displayed in 3-D graphic of $STK/VO^{TM}$.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.2
• /
• pp.203-210
• /
• 2010

For the development of a better product which fits to the target user population, physical workloads such as reach and visibility are evaluated using digital human simulation in the early stage of product development; however, ergonomic workload assessment mainly relies on visual observation of reach envelopes and view cones generated in a 3D graphic environment. The present study developed a quantitative assessment method of physical workload in a digital environment and applied to the evaluation of a Korean utility helicopter (KUH) cockpit design. The proposed assessment method quantified physical workloads for the target user population by applying a 3-step process and identified design features requiring improvement based on the quantified workload evaluation. The scores of physical workloads were quantified in terms of posture, reach, visibility, and clearance, and 5-point scales were defined for the evaluation measures by referring to existing studies. The postures of digital humanoids for a given task were estimated to have the minimal score of postural workload by finding all feasible postures that satisfy task constraints such as a contact between the tip of the index finger and a target point. The proposed assessment method was applied to evaluate the KUH cockpit design in the preliminary design stage and identified design features requiring improvement. The proposed assessment method can be utilized to ergonomic evaluation of product designs using digital human simulation.