서어보 밸브-피스톤 조합장치에서 유체의 온도가 피스톤 속도에 미치는 영향

유삼현 陸軍士官學校 1992 한국군사학논집 Vol.43 No.-

The main purpose of this study is to find the effect of hydraulic oil temperature on the velocity of piston for a servovalve-piston combination system. Theoretical approach based on the valve controlled piston which was allied on H.E.Merritt. Hydraulic Oil MIC138-CJ was used in this study ; the value of bulk modulus was maintained about 1034.2 MP and assuming that water and air were not included in hydraulic oil in order to get the purpose of study. The values of oil density and viscosity were changed according as the oil temperature was changed. Because the system was usually operated in the range 15℃~40℃, this range was selected in this study. These changed values will affect the velocity of piston in srevovalve-piston system. Those results were shown in the time domain transient responses and were analyzed in terms of the velocity of piston.

LQR 기법을 이용한 로봇다리의 다중입력 유압시스템 제어에 관한 연구

유삼현,임수철,Yoo, Sam-Hyeon,Lim, Soo-Chul 한국군사과학기술학회 2009 한국군사과학기술학회지 Vol.12 No.4

In the near future, military robots are likely to be substituted for military personnel in the field of battle. The power system of a legged robot is considerably more complex than the one used for a land vehicle because of the coordination and stability issues due to the large number of degree of freedom. In this paper, a servovalve-piston combination system for a straight-line motion of robot leg is modeled as three degree of freedom based on double inputs and single output transfer function. The output is the displacement of piston from neutral. The inputs are valve displacement from neutral and arbitrary load force in this system. LQR(Linear Quadratic Regulator) technique is applied in order to achieve robust stability and fast responses of the system. The Kalman filter loop, rejection of disturbance and noise, riccati equation, filter gain matrix, and frequency domain equality are analyzed and designed.

동적 거동을 이용한 연식주퇴장치의 주퇴력 저감 기법 연구

유삼현,이재영,이종우,조성식,김주희,김인수,임수철,Yoo, Sam-Hyeon,Lee, Jae-Yeong,Lee, Jong-Woo,Jo, Seong-Sik,Kim, Ju-Hee,Kim, In-Su,Lim, Soo-Chul 한국군사과학기술학회 2007 한국군사과학기술학회지 Vol.10 No.4

The future combat system is likely to be studied and developed in terms of enhancing both firepower and mobility simultaneously. Increased firepower often necessitates a heavier firing system. In return, the body of the vehicle needs to be light-weight in order to improve the mobility of the whole system. For this reason, in the areas of weapons systems such as the tank and self-propelled artillery, a number of studies attempting to develop designs that reduce recoil force against the body of the vehicle are being conducted. The current study proposes a tank construction that has a mass-spring-damper system with two degrees of freedom. A tank structure mounted with a specific soft recoil system that was implemented using a soft recoil technique and another tank structure based on a general recoil technique were compared to each other in order to analyze the recoil forces, the displacements of recoil, and the firing intervals when they were firing. MATLAB-Simulink was used as a simulating tool. In addition, the relationship between the movement of the recoil parts and the positions of the recoil latches in each of the two structures were analyzed. The recoil impact power, recoil displacement, firing interval, and so on were derived as functional formulas based on the position of the recoil latch.

PID 제어 기술을 이용한 비선형 유압 시스템의 강인 제어

유삼현,이종원,Yu, Sam-Hyeon,Lee, Jong-Won 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.5

Even though the hydraulic servo system has been widely used in industrial and military equipments since it has a lot of advantages, it is not easy to design controller due to the high nonlinearities and the parametric uncertainties. The dynamic behavior of the real process in the hydraulic servo system differs from that described by its model because the model is linearized. Another reason of the difference is caused by the variety of parameters, since the system parameters of the dynamic equation are affected by the operating conditions such as temperature and pressure. In this study, the designing process of the MRNC with a PID compensator is introduced and applied to the load sensing hydraulic servo system. The results show that the designed controller guarantees the robust control performance despite of both the nonlinearities and the parametric uncertainties.

차기 보병전투장갑차 포신 처짐량 예측 및 명중률 분석

유삼현,정동윤,오명호,신내호,남석현,Yoo, Sam-Hyeon,Chung, Dong-Yoon,Oh, Myoung-Ho,Shin, Nae-Ho,Nam, Suk-Hyun 한국군사과학기술학회 2006 한국군사과학기술학회지 Vol.9 No.3

A gun barrel of infantry fighting vehicle is supported like a type of cantilever. Temperature of a gun barrel is increased by heat transfer due to the combustion of propellant charge during the firing. Thus, the muzzle of a gun barrel is deflected in accordance with its temperature and the accuracy rate is decreased by deflection of the muzzle. In this study, deflection of a gun barrel is estimated by measuring its restoration rate because measuring the deflection rate is difficult due to the vibration of the gun barrel during the firing. In order to obtain the relations between deflection rate and restoration rate of the 40mm gun barrel of Next Infantry Fighting Vehicle(NIFV) under varying temperature, measurement of deflection rate and restoration rate is carried out using 5.56mm Remington rifle barrel. Effect of the estimated deflection rate of a gun barrel of NIFV on the hit probability is also analyzed.

무기탑재 전투차량의 임무부하분석을 위한 OMS/MP 방법론과 적용 연구

유삼현,이종우,이민형,이승민,장명언,Yoo, Sam-Hyeon,Lee, Jong-Woo,Lee, Min-Hyung,Lee, Seung Min,Jang, Myeong-Eon 한국군사과학기술학회 2013 한국군사과학기술학회지 Vol.16 No.1

To obtain the requirements of capability and analyze mission loads for weapon systems which are in process of development, Operational Mode Summary/Mission Profile(OMS/MP) should be documented in advance. In this paper, we have proposed a systematic and practical OMS/MP model processes of a weapon mounted combat vehicle for analyzing power and energy strategy. The wartime and peacetime OMS/MP of a hybrid wheeled combat vehicle which is mounted with an anti-tank guided weapon(ATGW) is also presented as its application.

출산의 지연변천 분석과 완결출산율 추계

유삼현 통계청 2022 통계연구 Vol.27 No.1

The postponement transition of fertility indicates a long-lasting shift of childbearing to later ages and a concomitant fertility decline. This study examines whether the postponement transition has taken place in South Korea and also explore possible approaches for projecting completed fertility. Building on prior studies, I analyze the postponement and recuperation process of cohort fertility in South Korea. The results are utilized to make the projection scenarios of completed fertility up to 1989 birth cohort. Data for this study come from the 1981-2020 Birth Registration Data and the Population Projections 2017-2047. The results suggest that since the 1969 birth cohort, the postponement transition of fertility has been taking place in Korea. While fertility postponement at earlier ages has continued to increase, only less than half of the postponement has been recovered at advanced ages. As the fertility recuperation at older ages displays signs of stagnation and decline, completed fertility is expected to decline further among the latest birth cohorts that are in the middle of reproductive years. 출산의 지연변천(postponement transition of fertility)은 저출산 사회의 출산율 변동을 출산연령의 증가와 출산수준의 복잡한 상호작용으로 설명하는 인구학적 개념이다. 이 연구는 출산의 지연변천을 한국 사회에 적용하여 코호트 관점에서 분석하고, 그 결과를 토대로 코호트 완결출산율을 전망한다. 1981∼2020년 출생신고자료와 추계인구를 사용하여 준거모형과 관계모형 등 세부 분석방법을 적용하였다. 연구결과, 한국 사회에서 1969년 출생코호트 이후 출산의 지연변천이 진행되어 왔음을 확인하였다. 1969년 출생코호트 대비 후행 출생코호트에서 20대의 출산율 감소가 지속되는 반면, 30대 이후 출산율 반등은 상대적으로 제한적인 수준에 머무르고 있었다. 출산지연과 회복의 전개과정이 현 수준으로 유지될 경우 1980년대에 출생한 코호트에서도 완결출산율 하락이 지속될 것으로 전망된다. 이 연구는 출산의 지연과 회복 과정을 실증적으로 분석하고, 출산율 변동에 관해 코호트 논의에 기여한 의의가 있다.

국제결혼 부부의 이혼분석

유삼현,유정균 한국인구학회 2019 한국인구학 Vol.42 No.2

Intermarriage across race and ethnicity is often regarded as one of the most important indicators of immigrants social integration. We extract the marriage cohort of 2010 from vital statistics on marriage and divorce 2010-2016. With discrete-time hazard models, we analyze the divorce risk of intermarriage couples between Korean and foreign-born spouse and compare to that of Korean couples. Findings suggest that intermarriage couples had a higher risk of divorce than couples among Koreans. Compared to Korean couples, however, the relative risk of divorce among intermarriage couples varies with country-specific origins. For instance, intermarriage with US-born husbands, Vietnam-born or Cambodia-born wives showed rather lower levels of divorce risk than to Korean couples when educational attainment and marriage age from each spouse and marriage duration were taken into account. Results suggest that intermarriage couples in Korea are ethnically and socio-economically heterogeneous groups and therefore, are not necessarily associated with a higher risk of divorce than ethnically homogeneous couples. 국제결혼 부부의 결혼안정성은 외국인 배우자의 적응과 사회적 통합이라는 측면에서 중요한의미를 갖는다. 이 논문은 우리 사회에서 한국인과 외국인의 결합으로 구성된 국제결혼 부부의결혼안정성이 한국인끼리 결합된 한국인 부부와 구별되는지를 확인하고 그 인과관계를 좀 더이해하기 위한 것이다. 2010~2016년 혼인과 이혼 동태통계 원자료를 활용하여 2010년 결혼코호트를 대상으로 이혼까지 걸린 시간을 이산시간위험모형(discrete-time hazard model)을 통해 분석하였다. 분석결과 남편 또는 아내의 출생국적이 한국이 아닌 외국일 경우 각각 양측 모두 한국인인 부부에 비해 이혼위험이 높은 것으로 나타났다. 남편 보다는 아내가 외국인일 경우 이혼위험이 상대적으로 더 높았으며, 남편과 아내의 교육수준과 혼인연령을 고려할 경우 두 집단의이혼위험 차이가 크게 감소하였다. 특히 외국인 남편과 아내의 출신 국적별로 세분화하였을 때, 남편의 출생국적이 미국, 아내의 출생국적인 베트남이나 캄보디아인 경우 한국인 남편과 아내보다 오히려 더 낮은 이혼위험을 갖는 것으로 나타났다. 논문의 결과는 국제결혼이 당연히 높은이혼위험과 연관되는 것은 아니며 출신국적과 혼인연령, 교육수준 등 다양한 요인을 함께 고려해야 함을 재확인시켜주고 있다.

구조적 불확실성을 갖는 유압기기의 H_∞ 제어

유삼현,최진희 陸軍士官學校 1997 한국군사학논집 Vol.53 No.-

Model Based Compensator 기술을 이용한 F-15 기동연습 자동장치의 다변수 제어

유삼현,최진희 陸軍士官學校 1998 한국군사학논집 Vol.54 No.-

An Autopilot can be used to provide precise control to meet the demanding requirement-performance and stability specifications-of flight research maneuvers with high-performance aircraft. This paper presents the Model Based Compensator(MBC) technique in order to control a flight test maneuver autopilot which is the multi-input multi-output(MIMO) system for an F-15 aircraft. Target loop is designed by the demanding requirements such as cross-over frequency, disturbance rejection in low frequency domain, zero steady-state error, identification of maximum and minimum singular values and sensor noise rejection in high frequency domain. Simulation will be continued in frequency domain until the plant with MBC comes close to the target loop. Kalman filter loop, Riccati equation, frequency domain equality, filter gain matrix, control gain matrix are presented to design the desired compensator. The effectiveness of MBC is illustrated by their application to an F-15 air craft to ensure acceptable aircraft performance during a maneuver.