• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.9
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• pp.934-942
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• 2007

In this study, the characteristics of the load-sensitive hydraulic control system for closed center type of a wheel loader were analyzed using developed analysis program based on Amesim tool. From the parametric analysis, the effects of each factor were revealed. Through the simulation with varying parameters, the system parameter effects on the controllable region and the pump pressure and load pressure variations were studied. The results were compared with the experimental ones. The results and discussions of the present paper could aid in the design of a load-sensitive hydraulic control system for closed center type.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.528-532
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• 1987

Closed-loop fiber-optic gyroscope with linear scale factor for a wide dynamic range is demonstrated using a gating process and two-harmonic phase modulation, of which the second harmonic is obtained by a frequency doubler. Also the effects of the second harmonic and duty cycle of gating signal on the linearity of scale factor are estimated theoretically and compared with the measured data. The experimental results show the best linearity of scale factor is about 0.5% within the rotation rate 90.deg./sec. The closed-loop fiber-optic gyroscope with gated two-harmonic phase modulation can be used in the application demanding less sensitive performance and modest scale factor linearity.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.166-175
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• 1999

This paper describes a design and performance evaluation of robust controller which overrides unstable motion and pulls out quickly after water entry of underwater vehicle dropped from aircraft or surface ship. We use 6-DOF equation for model of motions and assume parameter uncertainty to reflect the difference of real motion from modelled motion equation. we represent a nonlinear system with uncertainty as Takagi and Sugeno's(T-S) fuzzy models and design controller stabilizing them. The fuzzy controller utilizes the concept of so-called parallel distributed compensation (PDC). Finally, we confirm stability and performance of the controller through computer simulation and hardware in the loop simulation (HILS).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.24-33
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• 2004

In this paper, the helicopter flight control system using online adaptive neural networks which have the universal function approximation property is considered. It is not compensation for modeling errors but approximation two functions required for feedback linearization control action from input/output of the system. To guarantee the tracking performance and the stability of the closed loop system replaced two nonlinear functions by two neural networks, weight update laws are provided by Lyapunov function and the simulation results in low speed flight mode verified the performance of the control system with the neural networks.

• Journal of Korean Association for Spatial Structures
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• v.8 no.4
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• pp.73-80
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• 2008

The objective of current study is to develop an optimization technique for the seismic actively controlled building structures using active tendon devices by an efficient solution of LQR control gain. In order to solve the active control system, the Ricatti closed-loop algorithm has been applied, and the state vector has been formulated by the transfer matrix and solved by a numerical technique of the trapezoidal rule. The time-delay problem has been also considered by phase compensation. To optimize the performance index, the ratio of the weighted matrix is the design variable, allowable story drift limits of IBC 2000 and tendon forces have been applied as restraint conditions, and the optimum control program has been developed with the algorithm of the SUMT technique. In examples of the optimization problem of eight stories shear buildings, it is evaluated that the optimum controlled building is more suitable in the control of earthquake response than the uncontrolled system and can reduce the performance index to compare with the controlled system with a constant ratio of the weighted matrix.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.416-419
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• 2010

본 논문은 친환경 운전(Eco Driving)에 대한 사회적, 기술적 관심이 고조되고 있는 현 상황에서 차량에서 제공하는 차량 정보 가운데 MAF 센서 값을 이용하여 차량의 주행 연비를 추정하고자 하였다. MAF는 화학반응에서 연료 1g당 혼합되는 공기의 양을 의미하며, g/s의 단위를 사용한다. 휘발유 차량의 경우 엔진 ECU에서 폐회로 제어를 통해 혼합비를 14.7:1로 일정하게 유지하는 동작을 수행하므로 우리는 MAF 값을 통해 차량의 주행 연비 추정이 가능하다. 본 논문에서는 국내에서 생산중인 차종들에 대해 MAF 값을 이용한 실제 주행 테스트 수행하였으며, 이에 대한 연비 결과를 종합적으로 비교 분석하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.209-211
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• 2020

운송기관의 온실가스 저감을 위해 배터리-수소연료전지 하이브리드 철도추진시스템에 대한 연구가 활발히 진행되고 있다. 이 중 배터리는 빠른 응답 특성으로 하이브리드 철도추진 시스템의 효율을 극대화 시키기 위해 주요 전원으로 사용되고 있어, 시스템의 안전성 및 신뢰성을 높이기 위해 정확한 열화추정이 요구되고 있다. 본 논문에서는 사전 모델의 수립이 필요하지 않고 미소 용량 및 폐회로 제어가 가능한 재귀 최소제곱 추정 기법을 이용한 리튬이온 배터리의 SOH 추정 기법을 제안하였으며, 1S18P 배터리 모듈을 통해 열화 추정결과를 검증하였다.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.230-248
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• 2003

In this work an integrated model for paper plants combining wet-end and dry section is developed and a model predictive control scheme based on the plant model is proposed. Closed-loop process identification method is employed to produce a state-space model. Thick stock, filler flow, machine speed and steam pressure are selected as Input variables and basis weight, ash content and moisture content are considered as output variables. The desired output trajectory is constructed in the form of 1st-order dynamics. Results of simulations for control of grade change operations are compared with plant operation data collected during the grade change operations under the same conditions as in simulations. From the comparison, we can see that the proposed model predictive control scheme reduces the grade change time and achieves stable steady-state.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.4
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• pp.560-565
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• 2020

Korea's seaweed is using a method that is not suitable for the automated process and quality are significantly lower than the export volume of 20,000 tons or more. Therefore, in this paper, we improved the existing dry steaming weight control device and electronicized the remote control system and the existing dry steaming weight control device. This is implemented with precise and detailed device, unlike the dry seaweed weight control method using the conventional valve which depends on the user's feeling and experience. Also, because it is a remote control system, it can help to produce seaweed safely even if you don't climb on the machine. The Seaweed weight control device implemented is expected to contribute greatly to the automation process and industrial growth of the steeply growing dry laver production and export industry.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1089-1098
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• 1992

This paper concerns a discrete time control of noncolocated flexible mechanical systems by using time delay relation. A stability criterion of closed-loop system is derived in discrete time domain and a graphic method is developed for designing controllers. Based on this method, a derivative controller is designed for a simply supported uniform beam in the cases of colocation without time delay and of noncolocation with time delay. Some simulation results show the effectiveness of the suggested control.