• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1147-1156
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• 1993

In order to analyze lateral control in the backward maneuver of a tractor -trailer combination , a kinematic vehicle model and a human operator model with time delay were utilized for the operator/vehicle system. The analysis was carried out using the frequency domain approach. The open-loop stability of the vehicle motion was analyzed through the transfer functions. The sensitivity of the stability of the vehicle motion. to a change in the steering angle, was also analyzed. A mathematical model of the closed -loop operator/vehicle system was then formulated. The closed -loop stability of the operator /vehicle system was then analyzed. The effect of the delay time on the system was also analyzed through computer simulation.

• Journal of Mechanical Science and Technology
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• 제18권1호
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• pp.122-131
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• 2004

A constraint equation-based control law design for large angle attitude maneuvers of flexible spacecraft is addressed in this paper The tip displacement of the flexible spacecraft model is prescribed in the form of a constraint equation. The controller design is attempted in the way that the constraint equation is satisfied throughout the maneuver. The constraint equation leads to a two-point boundary value problem which needs backward and forward solution techniques to satisfy terminal constraints. An observer-based tracking control law takes the constraint equation as the input to the dynamic observer. The observer state is used in conjunction with the state feedback control law to have the actual system follow the observer dynamics. The observer-based tracking control law eventually turns into a stabilized system with inherent nature of robustness and disturbance rejection in LQR type control laws.

• 한국경영과학회지
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• 제39권3호
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• pp.51-61
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• 2014

In this paper, we deal with developing a cost estimation relationships (CER) for Korean maneuverable weapons systems using historical production cost. To develop the CER, we collected the historical data of the production cost of four tanks and five armored vehicles. We also analyzed the Required Operational Capability (ROC) of the weapons systems and chose cost drivers that can compare operational capabilities of the weapons systems We used Forward selection, Backward selection, Stepwise Regression and $R^2$ selection as the cost drivers which have the greatest influence with the dependent variables. And we used Principle Component Regression, Robust Regression and Weighted Regression to deal with multicollinearity and outlier among the data to develop a more appropriate CER. As a result, we were able to develop a production cost CER for Korean maneuverable weapons systems that have the lowest cost errors. Thus, this research is meaningful in terms of developing a CER based on Korean original cost data without foreign data and these methods will contribute to developing a Korean cost analysis program in the future.

• 대한조선학회논문집
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• 제29권3호
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• pp.45-52
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• 1992

조종운동(操縱運動)의 정확(正確)한 예측(豫測)이 절실(切實)하게 요구되는 항만내(港灣內)에서의 조종운동(操縱運動)과 같이, 저속(低速)이며 또 천수역(淺水域)에서의 선박(船舶)의 조종운동(操縱運動)을 잘 표현(表現)하는 수학(數學) Model은 아직 얻어지지 않고 있는 것이 현재까지의 실정(實情)이라 할 것이다. 일본의 Kose는 저속시(低速時) 선체유체력(船體流體力)의 새로운 Model을 제안(提案)한 바 있으나 아직 그 유용성에 대해서는 다방면(多方面)에서 검토(檢討)가 필요(必要)하다고 할 것이다. 본(本) 논문(論文)은 이러한 현실(現實)에서, 우선 저속시(低速時)의 Hull 유체력(流體力)을 잘 표현(表現)할 수 있는 새로운 방법(方法)을 모색하여 이를 Kose의 Model이나 종래(從來)의 M.M.G.Model 또는 Cross-Flow Drag Model등과 비교하여, 저속시(低速時)의 선체(船體)에 작용(作用)하는 유체력(流體力)을 잘 나타낼 수 있는 Model을 개발하려고 한다. 수학(數學) Model의 우열(優劣)을 판정하는 방법으로서는, 일본의 RR-742부회(部會)에서 실험한 저속시(低速時)($f_n={\pm}0.06,\;U={\pm}0.3m/s$)의 전후진(前後進)에 대한 Bare Hull의 CMT결과로 얻어진 전후력, 횡력, 선회모멘트를 Data로 삼아 이들을 각각 Kose Model, Cross-flow Model, MMG Model 및 신(新) Model에 의하여 Fitting하고, Fitting의 표준편차(標準偏差)를 비교하였다.