• 드라이브 ㆍ 컨트롤
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• 제20권4호
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• pp.71-79
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• 2023

In the field of agricultural machinery, various on-field tests are conducted to measure design load for optimal design of agricultural equipment. However, field test procedures are costly and time-consuming, and there are many constraints on field soil conditions due to weather, so research on utilizing simulation to overcome these shortcomings is needed. Therefore, this study aimed to model agricultural soils using discrete element method (DEM) software. To simulate draft force, predictions are made according to travel speed and compared to field test results to validate the prediction accuracy. The measured soil properties are used for DEM modeling. In this study, the soil property measurement procedure was designed to measure the physical and mechanical properties. DEM soil model calibration was performed using a virtual vane shear test instead of the repose angle test. The DEM simulation results showed that the prediction accuracy of the draft force was within 4.8% (2.16~6.71%) when compared to the draft force measured by the field test. In addition, it was confirmed that the result was up to 72.51% more accurate than those obtained through theoretical methods for predicting draft force. This study provides useful information for the DEM soil modeling process that considers the working speed from the perspective of agricultural machinery research and it is expected to be utilized in agricultural machinery design research.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.203-209
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• 2007

As the vehicle electronic control technology quickly grows and becomes more sophisticated, a more efficient means than the traditional in-vehicle driving test is required for the design, testing, and tuning of electronic control units (ECU). For this purpose, the hardware-in-the-loop simulation (HILS) scheme is very promising, since significant portions of actual driving test procedures can be replaced by HIL simulation. The HILS incorporates hardware components in the numerical simulation environment, and this yields results with better credibility than pure numerical simulations can offer. In this study, a HILS system has been developed for ESP (Electronic Stability Program) ECUs. The system consists of the hardware component, which that includes the hydraulic brake mechanism and an ESP ECU, the software component, which virtually implements vehicle dynamics with visualization, and the interface component, which links these two parts together. The validity of HIL simulation is largely contingent upon the accuracy of the vehicle model. To account for this, the HILS system in this research used the commercial software CarSim to generate a detailed full vehicle model, and its parameters were set by using design data, SPMD (Suspension Parameter Measurement Device) data, and data from actual vehicle tests. Using the developed HILS system, performance of a commercial ESP ECU was evaluated for a virtual vehicle under various driving conditions. This HILS system, with its reliability, will be used in various applications that include durability testing, benchmarking and comparison of commercial ECUs, and detection of fault and malfunction of ESP ECUs.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.56-61
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• 2010

This paper presents dynamic clearance verification considering engine movement for vehicle engine room package and validates through physical vehicle test. Traditionally, static clearance guide has been used for engine room package, but it's only 2-dimension criteria that results in requiring unnecessary space and it's not possible to conduct engine movement with real driving conditions. Thus, the dynamic DMU considers engine movement based on 28 load cases that are Roll Data analyzed by CAE for maximum engine movement and visualizes part-to-part dynamic clearance into virtual space. The dynamic DMU enables to develop compact engine room package without unnecessary space. The result of comparison between simulation and physical test has 0.892 correlation coefficient.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.377-382
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• 2010

In lunar explorer development program, computer simulator is necessary to provide virtual environments that vehicle confronts in lunar transfer, orbit, and landing missions, and to analyze dynamic behavior of the spacecraft under these environments. Objective of simulation differs depending on its application in spacecraft development cycle. Scope of use cases considered in this paper includes simulation of software based, processor and/or hardware in the loop, and support of ground-based flight test of developed vehicle. These use cases represent early phase in development cycle but reusability of modeling results in the next design phase is considered in defining requirements. A simulator architecture in which simulator platform is located in the middle and modules for modeling, analyzing, and three dimensional visualizing are connected to that platform is suggested. Baseline concepts and requirements for simulator development are described. Result of trade study for selecting simulation platform and approaches of defining other simulator components are summarized. Finally, characters of lunar elevation map data which is necessary for lunar terrain generation is described.

• 한국정보통신학회논문지
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• 제19권8호
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• pp.1859-1866
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• 2015

본 논문은 파우더 메이크업 효과를 시뮬레이션 하는 새로운 방법을 제안한다. 간단하면서도 사실적인 색상을 표현할 수 있는 색상 발현 모델을 고안하고, 여러 색상의 인조스킨에 파우더를 도포한 사진 이미지 분석에 색상모델을 적용하여 파우더 고유의 투과색 및 도포 두께를 추출하였다. 또한, 실제 사람 피부에 도포된 파우더 도포 두께 패턴을 추출하고 이를 다른 사람의 사진 상에서 메이크업 시뮬레이션 하는 데 사용하여 파우더의 질감을 실감 있게 표현하였다. 실험 결과 제안된 메이크업 시뮬레이션은 사실적인 색감과 질감을 나타낸 것으로 평가되었으며, 파우더 색상을 가상으로 테스트 하는 데 사용할 수 있을 것으로 기대한다.

• 한국산학기술학회논문지
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• 제12권11호
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• pp.5202-5207
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• 2011

여러 산업 분야에서 온도 제어 시스템 설계는 매우 중요한 문제이다. 시스템 개발을 위해서는 개념적인 디자인, 실제 테스트를 위한 시스템 구현, 반복적인 실험을 통한 제어기 설계용 수식모델 도출, 제어기 설계 및 성능 테스트의 과정을 거친다. 통상적으로 실제 테스트 시스템 구현 및 반복적인 실험을 통한 모델링, 제어기 설계 및 성능 테스트에 매우 많은 시간과 비용이 소요된다. 대부분의 온도 제어 시스템 설계 문제에서 동작 온도는 복사 열전달은 무시될 수 있는 범위이며, 히터는 듀티비를 이용하여 ON/OFF 방식으로 제어된다. 본 논문에서는 이러한 조건에서 개념적인 초기 시스템 디자인 후 제어기 설계용 모델 도출에서부터 제어기 설계 및 제어성능 예측까지의 전 과정을 자동으로 수행할 수 있는 기법을 제시하여 온도 제어 시스템의 초기 설계를 손쉽고 빠르게 검증 할 수 있도록 하였다. SISO (Single Input Single Output) 시스템을 예로 들어 제안한 기법의 유용함을 보였다.

• 한국군사과학기술학회지
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• 제17권3호
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• pp.318-326
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• 2014

The Shipyard Test of Naval Combat System depends on external factors, such as weather conditions and availability of its sensor-weapon, due to the need of on-board sensor-weapon during the test. This paper suggests the Supportive Equipment using virtual simulator for Shipward Test, in case of the unavailability of the on-board sensor-weapon or the test support force(aircraft, surface ship etc.), to pre-check the functions of the combat system as well as to prepare the Shipyard Test. To mock the real sensor-weapon functions as similar as possible, the Supportive Equipment for Shipyard Test was verified by the Verification and Validation process, which is usually performed while developing models in the Modeling & Simulation field.

• 한국항행학회논문지
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• 제27권6호
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• pp.788-797
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• 2023

본 논문은 수직 이착륙 무인 항공시스템의 GPS (global positioning system) 불가 시 대체 항법 시스템으로의 영상보정항법 시스템을 시험하기 위한 검증환경 개발 내용을 소개한다. 개발 중인 영상보정항법 시스템의 시험 및 평가를 위해서는 가상 환경을 활용하는 것이 효율적이지만, 현재 국내에는 적합한 장비가 개발되어 있지 않다. 따라서 제안된 검증환경은 시험 대상 장비의 운용 환경을 모델링 및 시뮬레이션 하여 입력 신호를 생성하고, 출력 신호를 관측함으로써 대상 장비의 성능을 평가할 수 있도록 개발되었다. 연구 과정은 검증환경 요구도 생성, 검증환경 설계에서부터 구성품별 하드웨어 및 소프트웨어 설계, 제작까지 포괄적으로 기술되었다. 이를 바탕으로 제작된 검증환경을 개발 중인 영상기반 보정항법 알고리즘의 성능평가와 시뮬레이션 기반의 사전 비행시험 수행에 활용하였다.

• 드라이브 ㆍ 컨트롤
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• 제10권1호
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• pp.7-13
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• 2013

Port size 80mm or above large-flow type solenoid valves are extensively used in dust collector and power plants. These multi-stage solenoid valve have few problem. first, multi-solenoid valves are almost depend on imports and there are weak in the brine environment and the low energy efficiency. Because these problem, increased the necessity of research on the development of large flow and high pressure type solenoid valves. In this study, describe the design method of multi-stage solenoid test bench and confirm the influence valve performance on several parameter such as diaphragm orifice diameter. At first, each part has modeled by AMESim simulation tool and combining them. This AMESim virtual multi-stage solenoid valve found influence valve performance on the valve parameter. Finally developed the multi-stage solenoid valve and verified that performance on experimental result.

• 설비공학논문집
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• 제25권7호
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• pp.406-412
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• 2013

A hybrid heat pump is under development with the goal of utilizing 120% of primary energy resources. A plate heat exchanger is added between the compressor and air-cooled condenser of an ordinary heat pump to heat water. For successful operation of the heat pump, it is necessary to develop a control algorithm under various operating conditions. As a virtual test bed for that purpose, a dynamic model has been developed, to simulate its dynamic behavior. It was modeled in transient one-dimensions, with varying phase lengths considered. The model was implemented in Matlab and Simulink. Simulation results were effectively applied to design a control algorithm. They also provided physical insight into how to design and operate the system.