• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.8
• /
• pp.216-223
• /
• 1999

This study was intended to determine the inertia , damping and stiffness properties of the cab-suspension of agricultural tractors by applying the direct system identification method (DSIM). Since the rigid and elastic modes of the cab-suspension are not likely to be separated clearly, direct application of the DSIM may result in large computation error. To solve such a problem, a method of locating mass center of the cab were determined by assuming the behavior of the cab-suspension is a rigid body motion. The dynamic parameters of the cab-suspension were then determined by applying the DSIM with the known coordinates of the mass center. The constraints of spatial matrices of the cab-suspension also make the algorithm for the DSIM perform better. The values of dynamic parameters determined by this method agreed well with those determined by the experiment.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.514-516
• /
• 2004

국내 및 국외에서 많은 시뮬레이션 환경이 개발되어 다양한 시뮬레이터 개발에 활용되고 있다. 이러한 시뮬레이션 환경은 다양한 기능을 갖추고 있어 시뮬레이터 개발편의를 도모하고 있다. 이러한 시뮬레이션 환경에서는 시뮬레이션 스케줄링(Scheduling), 데이터베이스(Database), 모델 컴파일 그리고 디버거(모니터링 및 제어기능 툴)등을 제공한다. 이미 국내 및 국외 업체에서 시뮬레이션 환경이 개발되어 왔지만, 3차원적인 시뮬레이션을 필요로 하는 시뮬레이션 환경은 미비한 상태로 로봇공학이나 3차원 시뮬레이션이 필요한 산업에 앞으로 더욱더 개발이 필요한 실점이다. 본 논문에서는 3차원 시뮬레이션을 하기 위한 방안으로 개발된 3D 모델빌더와 시뮬레이션 환경인 3DSIM(3D Simulation Environment)을 소개한다. 3DSIM은 현재 사용되고 있는 시뮬레이션 환경과는 다른 형식의 구조를 갖추고 있어 일반 시뮬레이션 환경과의 차이점에 대해 알아본다. 일반적인 시뮬레이션 환경은 서버와 클라이언트로 나뉘어 서버에서는 특정 모델에 대한 연산을 수행하기 위한 환경을 제공하며, 클라이언트에서는 서버에서 수행된 연산을 효율적으로 분석하기 쉽도록 보여주는 환경으로 나된다. 하지만, 3차원 시뮬레이션 환경인 3DSIM은 3차원 객체를 디자인하는 과정이 필요하며, 3차원 객체를 디자인하였을 경우, 각각의 파라미터를 통하여 시뮬레이션 되어야 한다는 점에서 일반적인 시뮬레이션 환경과의 구조가 다르게 된다. 3DSIM개발을 통하여 3차원 시뮬레이터 개발을 보다 편하게 개발할 수 있도록 하였으며, 시뮬레이션 모니터링 및 제어가 용이하도록 개발하였다.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1336-1345
• /
• 2016

A modified space vector pulse width modulation (SVPWM) strategy based on vector space decomposition and its equivalent carrier-based PWM realization are proposed in this paper, which is suitable for six-phase asymmetrical dual stator induction machines (DSIMs). A DSIM is composed of two sets of symmetrical three-phase stator windings spatially shifted by 30 electrical degrees and a squirrel-cage type rotor. The proposed SVPWM technique can reduce torque ripples and suppress the harmonic currents flowing in the stator windings. Above all, the equivalent relationship between the proposed SVPWM technique and the carrier-based PWM technique has been demonstrated, which allows for easy implementation by a digital signal processor (DSP). Simulation and experimental results, carried out separately on a simulation system and a 3.0 kW DSIM prototype test bench, are presented and discussed.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.1
• /
• pp.133-138
• /
• 2011

This paper proposes a simple but robust self-tuning fuzzy logic controller for the speed regulation of a dual star induction machine based on indirect field oriented control. For feed the two star of this machine, two voltage source inverters based on sinus-triangular pulse-width modulation techniques are introduced. The simulation results show the robustness and good performance of the proposed controller.

• Journal of the Korean GEO-environmental Society
• /
• v.22 no.10
• /
• pp.21-29
• /
• 2021

Most concrete gravity-type dams in and out of the country were constructed by column method to control cracks caused by concrete hydration heat generated during construction, resulting in a certain level of leakage after impoundment through various causes, such as contraction joints and construction joints. However, due to the characteristics of concrete structures that shrink and expand according to temperature, concrete dams have vertical joints and drains to allow penetration. PVC waterproof shows excellent effects in completion of the dam, which however increases the possibility of interfacial failure due to different thermal expansion. Other causes of penetration may include problems with quality control during installation, generation of cracks due to heat of hydration of concrete, waterproofing methods, etc. In the case of Bohyunsan Dam in Yeongcheon, North Gyeongsang Province, the amount of drainage in the gallery was checked and underwater, and it was confirmed that there are many penetrations from drainage holes connected to vertical joints, and that some of the PVC waterproofs are not fully operated. As a new method to prevent penetration through vertical joints, D.S.I.M. (Dam Sealing Innovation Method) developed by World E&C was applied to Bohyunsan Dam and checked the amount of drainage in the gallery. As a result of first testing three most leaking vertical joints, the drain in the gallery was reduced by 87% on the average and then applied to the remaining 13 locations, which showed a 83% reduction effect based on the total drain in the gallery. Summing up these results, it was found that D.S.I.M. preventing water leakage from the upstream face is a valid construction method to reduce the water see-through and penetration quantity seen in downstream faces of concrete dams. If D.S.I.M. is applied to other concrete dams at domestic and abroad, it is expected that it will be very effective to prevent water leakage through vertical joints that are visible from downstream faces.