• 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.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1304-1307
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• 1996

In this paper, we present a robust Two Degree of Freedom (TDF) $H_{\infty}$ controllers for a missile system. The feedback controller is designed to meet robust stability and disturbance rejection specifications while the prefilter is used to improve the robust model matching properties of the closed loop system. As the perturbed model, we use the normalized coprim factor perturbations. These controllers are designed using $H_{\infty}$ optimization procedures, and applied to a missile model via simulation.

• 전기의세계
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• 제31권4호
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• pp.296-302
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• 1982

The computer algorithm and program are developed to obtain the Luenberger Canonical form and the transform matrices for linear time invariant multivariable control systems. The model controller of an eigth order system, which assigns the modes of the multivariable control systems and closed-loop matrices are computed numerically by the developed programs. It is shown that the computed results coincide with the Luenberger's and Kalman's method. The gain of the model controller has varied from 10$^{-3}$ to 10$^{5}$ by the modes assignment of the open-loop system.

• 대한전기학회논문지:전력기술부문A
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• 제48권8호
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• pp.996-1003
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• 1999

This paper propose a position-speed controller with an estimator which can estimate states and disturbance. The overall control system consists of two parts: the position-speed controller and an estimator. The Kalman filter applied as state-feedback controller is an optimal state estimator applied to a dynamic system that involves random perturbations and gives a linear, unbiased and minimum error variance recursive algorithm to optimally estimate the unknown state. Therefore, we consider the error problem about the servo system modeling and the measurement noise as a stochastic system and implement a optimal state observer, and enhance the estimate performance of position and speed using that. Using two-degree-of freedom(TDOF) conception, we design the command input response and the closed loop characteristics independently. The servo system is to improve the closed loop characteristics without affecting the command imput response. The characteristics of the closed loop system is improved by suppressing disturbance torque effectively with the disturbance observer using a inverse-transfer matrix. Therefore, the performance of overall position-speed controller is enhanced. Finally, the performance of the proposed controller is exemplified by some simulations and by applying the real servo system.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.139-145
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• 2004

This paper presents human-in-the-loop evaluations of vehicle stability control(VSC) system using a driving simulator. A driving simulator which contains full vehicle nonlinear model is evaluated by using actual vehicle test data on the same driving conditions. Braking control inputs for Vehicle Stability Control system have been directly derived from the sliding control law based on vehicle planar motion equations with differential braking. Closed-loop simulation results at realistic driving situations have shown that the proposed controller reduces driving effort of a driver and enhances stability of a vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1465-1469
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• 2003

In general satellite verification process, the AOCS (Attitude & Orbit Control Subsystem) should be verified through several kinds of verification test which can be divided into two major category like FBT (Fixed Bed Test) and polarity test. And each test performed in different levels such as ETB (Electrical Test Bed) and satellite level. The test method of FBT is to simulate satellite dynamics with sensors and actuators supported by necessary environmental models in ETB level. The VDS (Vehicle Dynamic Simulator) try to make the real situation as possible as the on-board processor will undergo after launch. The purpose of FBT test is to verify that attitude control logic function and hardware interface is designed as expected with closed loop simulation. The VDS is one of major equipments for performing FBT and consists of software and hardware parts. The VDS operates in VME environments with target board, several commercial boards and custom boards based on the VxWorks real time operating system. In order to make time synchronization between VDS and satellite on-board processor, high reliable semaphore was implemented to make synchronization with the interrupt signal from on-board processor. In this paper, the real-time operating environment used on VDS equipment is introduced, and the hardware and software configurations of VDS summarized in the systematic point of view. Also, we try to figure out the operational concept of VDS and AOCS verification test method with close-loop simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.276-278
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• 2006

In this paper, a complete solution to fuzzy-model-based digital redesign problem (IDR) for sampled-data nonlinear systems is presented, The term of intelligent digital redesign (IDR) is to design a digital fuzzy controller such that the sampled-data closed-loop fuzzy system is equivalent to the continuous-time closed-loop fuzzy system using the state matching, Its solution is simply obtained by linear transformation, Under the proposed sampled-data controller, the states of the sampled-data and continuous-time fuzzy system are completely matched at every sampling points.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.340-340
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• 2000

This paper aims at deriving an equivalent finite dimensional discrete-time system for H$_{\infty}$ type problem for sampled-data control systems. A widely used ph is based on the lifting technique, but it needs somewhat complicate computation. Instead this paper derives an equivalent finite-dimensional discrete-time system directly from a description of the sampled-data system which is achieved via a closed-loop expression of the worst-case intersample disturbance.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1663-1674
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• 2017

This paper deals with the robust speed regulation of a surface-mounted permanent magnet synchronous motor (SPMSM) that is subject to parametric uncertainties and external disturbances. The proposed approach retains a conventional cascade control configuration composed of an outer-loop speed control module and inner-loop current control modules. Baseline proportional-integral (PI) controllers are designed for nominal modular systems without accounting for the uncertainties to set a desired control performance of the closed-loop system. After studied in both frequency and time domains, a reduced-order proportional-integral observer (PIO), as a modular disturbance observer, is incorporated with each control module to maintain the ideal performance of the modules. Theoretical analysis confirms the desired performance recovery of the augmented system with modular PIOs to the nominal system. Comparative computer simulations and experimental results validate the proposed cascade control method for SPMSM speed regulation.

• 한국산업정보학회논문지
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• 제19권5호
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• pp.81-90
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• 2014

순방향물류와 역방향물류의 두 물류 체인을 통합해서 자원 순환형 공급체인 (CLSC: closed-loop supply chain) 을 구성하는 것은 기업의 비용절감을 위해서 반드시 필요한 요소이다. 본 연구에서는 순환형 공급체인의 환경에서 순방향물류의 도매점과 역방향물류의 처리센터의 재고를 통합하는 재고관리를 제안한다. JIT(Just-in-Time)배송이 고려된 새로운 CLSC 재고관리모델은, 회수센터에서 처리센터로 배송된 사용이 끝난 제품이 도매업자의 수요에 미치지 못할 때 제조사에게 필요한 제품을 재발주 할 것이지 사용이 끝난 제품의 회수를 기다릴 것이지를 선택함으로써 비용을 절감한다. 제안 모델의 유효성을 검증하기 위하여 최적화 기법중 하나인 유전자 알고리즘(Genetic Algorithm: GA)을 이용하였다. 파라미터가 해에 미치는 영향을 알아보기 위해서 세 가지 파라미터 조건에서 우선 순위형 GA (priority-based GA: priGA)와, 각 세대마다 파라미터가 조정되는 개량형 하이브리드 GA (modified Hybrid Genetic Algorithm: mhGA)를 사이즈가 다른 4가지 수치 예에 적용하여 시뮬레이션을 실시하였다.