• Title/Summary/Keyword: Real-Time Dynamic Simulation

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A Simulation Technique of the Shipboard INS Transfer Alignment Environments using Hardware-In-the-Loop Simulation (HILS를 이용한 함정의 관성항법장치 전달정렬 환경 모의 기법)

  • Kim, Woon-Sik;Yang, Tae-Soo;Kim, Sang-Ha
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.2
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    • pp.181-188
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    • 2011
  • A simulation technique, which simulate dynamic motion and communication environments of ship in the lab, is needed in order to reduce the testing cost when we evaluate the transfer alignment performance of shipboard INS. Hardware-In-the-Loop Simulation(HILS) can be used as an effective test method for those system because it can provide flexible and realistic simulation environments, various test scenario, and repeated test environment in the lab without additional cost and person. This paper presents the methods for implementing the real time HILS environment for testing transfer alignment performance of shipboard INS. It includes real time executive for controlling realtime simulation and calculating the ship motion, communication method for interfacing between the systems, and coordinate transformation method for converting real ship coordinate attitude data to lab coordinate attitude data.

Nonlinear Dynamic Simulation using SIMULINK (SIMULINK를 이용한 비선형 동적 해석)

  • Kim Seong Keol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.4
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    • pp.105-112
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    • 2005
  • Analyses of dynamic models which were one and two degrees of freedom, and had the nonlinear springs and dampings with certain polynomial functions were performed from SIMULINK in MATLAB. Those consisted of 12 programs and were built on the basis of the preceding programs fur the linear dynamic simulations. However the programs for the nonlinear simulations were quite different from those f3r the linear ones, and showed the results of the analyses in real time with animating. It was found that the programs would help us to solve any kind of nonlinear dynamic simulation with one and two degrees of freedom. Especially, the simulations for 1 DOF system with cubic nonlinear spring farce showed the results for Duffing's equation, of which phenomena were jump-up and jump-down. It will be applied to the dynamic simulation of the car seat vibration with a passenger, of which model has the equivalent nonlinear springs and is two degrees of freedom.

Development of KOMPSAT-2 Vehicle Dynamic Simulator for Attitude Control Subsystem Functional Verification

  • Suk, Byong-Suk;Lyou, Joon
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1465-1469
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    • 2003
  • In general satellite verification process, the AOCS (Attitude & Orbit Control Subsystem) should be verified through several kinds of verification test which can be divided into two major category like FBT (Fixed Bed Test) and polarity test. And each test performed in different levels such as ETB (Electrical Test Bed) and satellite level. The test method of FBT is to simulate satellite dynamics with sensors and actuators supported by necessary environmental models in ETB level. The VDS (Vehicle Dynamic Simulator) try to make the real situation as possible as the on-board processor will undergo after launch. The purpose of FBT test is to verify that attitude control logic function and hardware interface is designed as expected with closed loop simulation. The VDS is one of major equipments for performing FBT and consists of software and hardware parts. The VDS operates in VME environments with target board, several commercial boards and custom boards based on the VxWorks real time operating system. In order to make time synchronization between VDS and satellite on-board processor, high reliable semaphore was implemented to make synchronization with the interrupt signal from on-board processor. In this paper, the real-time operating environment used on VDS equipment is introduced, and the hardware and software configurations of VDS summarized in the systematic point of view. Also, we try to figure out the operational concept of VDS and AOCS verification test method with close-loop simulation.

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Linear Dynamic Simulation using SIMULINK (SIMULINK를 이용한 선형 동적 해석)

  • Kim Seong Keol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.3
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    • pp.110-116
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    • 2005
  • Linear dynamic simulations with one and two degrees of freedom were built from SIMULINK in MATLAB commercial program. Before starting the simulations, initial conditions and system parameters which are mass, spring constant and coefficient of damping are easily inputted by user through each pop-up window, and the conditions for the simulation including time step, analysis methodology and so on can be modified with ease. Also, as soon as the simulations are started, the windows for animations which shows deformed motions dynamically with real time are popped-up and the graphical results are shown in time and frequency domains, simultaneously, The results of the simulations were verified through some examples of textbooks of mechanical vibrations. It was found that the programs would help us to solve any kind of linear dynamic simulation for one and two degrees of freedom.

Development of an Real-time Multi-machine Power System Simulator using Personal Computers and Fast Ethernet (개인용 컴퓨터와 고속 이더넷을 이용한 다기 다모선 전력 시스템 실시간 시뮬레이터 개발에 관한 연구)

  • Kim, Joong-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.63-68
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    • 2009
  • As the complexity of the power system becomes higher, tests of the new devices, such as exciter and PCS(Power Conversion System) of the distributed generation sources, in the real operating condition are more important. However tests of the unverified devices in the real power system may cause hazardous malfunction of the system. In order to avoid this problem, power devices may be tested with the real-time simulators instead of the real power system. This paper presents an real-time multi machine power system simulator using PCs(Personal Computer) and Fast Ethernet. Developed real-time simulator performs the electro-mechanical dynamic simulation of multi-machine power system by the network distributed computing technique. Because the simulator consists of usual PCs and Fast Ethernet, it is possible to make up a simulation system very cheaper than the conventional real-time simulator which consists of dedicated expensive hardware devices. The performance of the developed simulator is tested and verified with the scaled model excitation system. The test which adjust the control parameters of the exciter is performed with the well-known New England 10 generator 39 bus sample power system.

Enabling role of hybrid simulation across NEES in advancing earthquake engineering

  • Gomez, Daniel;Dyke, Shirley J.;Maghareh, Amin
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.913-929
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    • 2015
  • Hybrid simulation is increasingly being recognized as a powerful technique for laboratory testing. It offers the opportunity for global system evaluation of civil infrastructure systems subject to extreme dynamic loading, often with a significant reduction in time and cost. In this approach, a reference structure/system is partitioned into two or more substructures. The portion of the structural system designated as 'physical' or 'experimental' is tested in the laboratory, while other portions are replaced with a computational model. Many researchers have quite effectively used hybrid simulation (HS) and real-time hybrid simulation (RTHS) methods for examination and verification of existing and new design concepts and proposed structural systems or devices. This paper provides a detailed perspective of the enabling role that HS and RTHS methods have played in advancing the practice of earthquake engineering. Herein, our focus is on investigations related to earthquake engineering, those with CURATED data available in their entirety in the NEES Data Repository.

Feedforward actuator controller development using the backward-difference method for real-time hybrid simulation

  • Phillips, Brian M.;Takada, Shuta;Spencer, B.F. Jr.;Fujino, Yozo
    • Smart Structures and Systems
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    • v.14 no.6
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    • pp.1081-1103
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    • 2014
  • Real-time hybrid simulation (RTHS) has emerged as an important tool for testing large and complex structures with a focus on rate-dependent specimen behavior. Due to the real-time constraints, accurate dynamic control of servo-hydraulic actuators is required. These actuators are necessary to realize the desired displacements of the specimen, however they introduce unwanted dynamics into the RTHS loop. Model-based actuator control strategies are based on linearized models of the servo-hydraulic system, where the controller is taken as the model inverse to effectively cancel out the servo-hydraulic dynamics (i.e., model-based feedforward control). An accurate model of a servo-hydraulic system generally contains more poles than zeros, leading to an improper inverse (i.e., more zeros than poles). Rather than introduce additional poles to create a proper inverse controller, the higher order derivatives necessary for implementing the improper inverse can be calculated from available information. The backward-difference method is proposed as an alternative to discretize an improper continuous time model for use as a feedforward controller in RTHS. This method is flexible in that derivatives of any order can be explicitly calculated such that controllers can be developed for models of any order. Using model-based feedforward control with the backward-difference method, accurate actuator control and stable RTHS are demonstrated using a nine-story steel building model implemented with an MR damper.

Practical and Verifiable C++ Dynamic Cast for Hard Real-Time Systems

  • Dechev, Damian;Mahapatra, Rabi;Stroustrup, Bjarne
    • Journal of Computing Science and Engineering
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    • v.2 no.4
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    • pp.375-393
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    • 2008
  • The dynamic cast operation allows flexibility in the design and use of data management facilities in object-oriented programs. Dynamic cast has an important role in the implementation of the Data Management Services (DMS) of the Mission Data System Project (MDS), the Jet Propulsion Laboratory's experimental work for providing a state-based and goal-oriented unified architecture for testing and development of mission software. DMS is responsible for the storage and transport of control and scientific data in a remote autonomous spacecraft. Like similar operators in other languages, the C++ dynamic cast operator does not provide the timing guarantees needed for hard real-time embedded systems. In a recent study, Gibbs and Stroustrup (G&S) devised a dynamic cast implementation strategy that guarantees fast constant-time performance. This paper presents the definition and application of a cosimulation framework to formally verify and evaluate the G&S fast dynamic casting scheme and its applicability in the Mission Data System DMS application. We describe the systematic process of model-based simulation and analysis that has led to performance improvement of the G&S algorithm's heuristics by about a factor of 2. In this work we introduce and apply a library for extracting semantic information from C++ source code that helps us deliver a practical and verifiable implementation of the fast dynamic casting algorithm.

Development of Equivalent Systems for the KEPCO Enhanced Power System Simulator (한전 실시간 시뮬레이터를 위한 등가계통 구성 연구)

  • Jang, Gil-Soo;Yun, Yong-Beum;Kim, Yong-Hak
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.11
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    • pp.1434-1440
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    • 1999
  • For the real-time power system analysis, there exists a limitation to the scale of the system to be simulated, hence it is necessary for the real-time simulation to develop reduced equivalent systems which preserve the desired property of the original system. In this paper, a procedure for developing an equivalent system whose scale is reduced within the hardware capacity of a real-time simulator is proposed. Also, the proposed procedure is applied to a KEPCO's system. The comparison between the original system and equivalent systems illustrates the capabilities of the proposed procedure.

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Modeling and Implementation of A Dynamic Reconfiguration Framework (동적 형상조정 프레임워크의 모델링 및 구현)

  • 윤태웅;민덕기
    • Journal of the Korea Society for Simulation
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    • v.12 no.3
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    • pp.83-94
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    • 2003
  • For 24 hours-7 days service on distributed systems, a great deal of efforts are investigated on high availability for seamless operation. In this paper, we propose a dynamic reconfiguration framework of distributed systems, called "hot-swapping" framework. This framework allows us to upgrade and exchange a number of modules of a distributed system without stopping running service as well as the system itself. In order to hide the state of service operation, the framework employes the "proxy" design pattern. Our framework provides two types of proxies: a static proxy and a dynamic proxy, Static proxies can achieve fast execution time, but they need to be changed whenever any minor change exists in the related swappable module. Meanwhile, dynamic proxies takes longer execution time, but do not need to be changed under minor changes of swappable modules. We compare performances of static and dynamic proxies and also apply the framework to a real situation with security management modules. management modules.

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