• Journal of Korean Institute of Industrial Engineers
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• v.16 no.2
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• pp.23-36
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• 1990

A unit-load automated guided vehicle system is considered in which a single vehicle is operated on a unidirectional path in a closed loop. The vehicle serves a manufacturing cell moving pallets from one station to another based on the "First-Encountered-First-Serve" dispatching rule. An approximation method is developed to compute the mean waiting time of an arbitrary pallet at each station. Extensive numerical experiments, performed for various problems, yield fairly good results in most of the cases compared with those obtained by simulation method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.181-185
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• 2001

This paper presents a digitally speed sensorless control system for induction motor with direct torque control (DTC). The drive is based on Mode1 Reference Adaptive System (MRAS) using state observer as a reference model fat flux estimation. The system are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal, model reference adaptive control (MRAS) with rotor flux linkages for the speed turning aignal at low speed range, two hysteresis controllers. The Proposed system is verified through simulation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.3
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• pp.126-131
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• 2002

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. The rotor position, which is an essential component of any vector control schemes, is calculated through the instantaneous stator flux position and an estimated flux value of rotating reference frame. A closed-loop state observer is implemented to compute the speed feedback signal. The validity of the proposed sensorless scheme is confirmed by simulation and its dynamic performance is examined in detail.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.5
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• pp.647-652
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• 1986

The controller tuning methods proposed by Yuwana-Seborg and Suh utilizes Pade first order approximation for the delay terms in the closed loop transfer function. In this paper, the use of a Pade second-order approximation method is investigated. The simulation results show that the new method is superior to pervious approaches such as Ziegler-Nichols and Cohen-Coon methods.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.40.1-40
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• 2001

In this paper, control theoretic approaches are proposed to guarantee QoS (Quality of Series) such as packet delay and packet loss of real-time traffic in high-speed communication network. Characteristics of variable rate real-time traÆc in communication networks are described. The mathematical model describing networks including source and destination nodes are suggested. By a traffic control mechanism, it is shown that worst-case end-to-end transfer delay of traffic can be controlled and packet loss can be prevented. The simulation shows results of delay control and buer level control to raise QoS in realtime traffic.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.299-304
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• 1991

A novel approach based on a nonlinear compensator is proposed to prevent 'windup', which is caused by the saturation of the actuator and the integration action of the controller. The anti-windup compensator is located between the conventional linear controller, designed neglecting the saturation, and the actuator. It was proven based on the describing function method that, if the closed loop control systems are stable assuming no saturation, then there exist a range of compensator gain which prevents any limit-cycle and hence, guarantees the system stability. The computer simulation results show that the compensator proposed in the manuscript can eliminate unstable limit cycle and improve the transient response.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.676-680
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• 1991

This paper proposes fuzzy control algorithms for a DC moter speed control. The proposed algorithms are constructed by the fuzzy controller and the fuzzy compensator. The fuzzy compensator used to overcome rapidly the effects caused by the disturbance and is mounted outside of the closed loop of the fuzzy controller. The fuzzy control rules are established from human operator experience and basic engineering knowledge about the process dynamics. Simulation results show that the proposed algorithms compensate for parameter variation and disturbance.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.332-337
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• 1988

A digital series-feedback compensator algorithm for tracking time-varying signal is presented. The series-feedback compensator is composed of one closed loop pole / zero cancellation compensator and one desired-input generator. This algorithm is applied to nonlinear hydraulic position control system. The hydraulic servo system is modelled as a second order linear model and cancellation compensator is modelled from it. The desired input generator is inserted to reduce modelling error. Digital computer simulation output using this control method is present and the usefulness of this control algorithm for nonlinear hydraulic system is verified.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.50-53
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• 1988

This paper presents an approach to the position control of a robot manipulator by using a self-tuning pole-placement controller with an inverse model. The linearized independent difference equations of manipulator motion are obtained, and the parameters of these models are estimated on line. The controller is composed of two parts, the primary controller obtains desired torques by using an inverse model and the secondary controller computes variational torques on the basis of induced perturbation equations by minimizing a quadratic criterion with a closed-loop pole-placement. Simulation is performed to demonstrate the effectiveness of this approach.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.554-559
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• 1986

This paper considers the problem of stabilizing a composite system formed by interconnecting a number of single-input single-output linear continuous systems. The problem is general in the sense that in addition to the standard assumption about the uncertainty of the subsystems, the strength of interconnections is assumed unknown. A method to design a local adaptive feedback control is first presented, and then the resultant closed-loop system is assured to be globally stable. Also, a numerical example is illustrated via computer simulation.