• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1469-1472
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• 1996

Hydraulic Hot Strip Mill (HHSM) rolls materials whose size and stiffness are various. So a roll gap controller for HHSM was designed using TDC(Time Delay Control) method. The performance of the roll gap control was evaluated through computer simulations. The simulation results indicate that TDC method show excellent robustness and tracking properties against PID control method in various rolling conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1133-1138
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• 1991

A control of nonlinear system is motivated by the fact that all real plants are nonlinear systems and model identification introduces parameter errors. The purpose of this study is to design a Discrete Variable Structure Controller(DVSC) for single-rod hydraulic cylinder system. The model contains uncertain parameters which we known to lie upper and lower bounds. In the design of DVSC, the boundary layer concept was adopted to reduce cattering. The DVSC was evaluated through digital computer simulation and compared with a VSC (analog controller).

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.299-304
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• 1988

This paper describes the application of the variable structure control(VSC) concept for the position control of electro-hydraulic servomtor system. The basic philosopy of VSC is that the structure of the feedback control is altered as the state crosses discontinuity surfaces in the state surface with the result that certain desirable properties are achieved. The switching of the control function yields total(or selective) invariance to system parameter variations and disturbances, and closed loop eigen value placement in time-varing and uncertain systems.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.945-950
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• 1991

A method to design a robust servomechanism by continuously variable structure control is proposed. The state and control signal of this servomechanism do notchatter since a continuous control scheme is used. The input-output relation of this servomechanism is determined by prescribing a hyperplane in a state space of which the neighborhood is asymptotically attractive everywhere. This control mechanism was applied to a single rod cylinder servomechanism which has the nonlinerities due to their nonsymmetrical structure and its excellency was verified.

• 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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• 1989.10a
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• pp.272-275
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• 1989

In this paper feedback linearization of valve-controlled nonlinear hydraulic velocity control system is studied. The $C^{\infty}$ nonlinear transformation T is obtained, and it is shown that this transformation is global one. Linear equivalence of nonlinear hydraulic velocity control system is obtained by this global nonlinear transformation, and linear state feedback control law is applied to this linear model. It is shown that this transformation method is to the linear approximation by simulation study..

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.276-281
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• 1989

Comparison 3-port servo system with 4-port is made to obtain optimal design for heavy and unidirectional hydraulic system, It is concluded that 3-port servo system it more adequate than 4-port for the heavy load system which is usually operated at lower frequencies. High performance electro-hydraulic position controller is designed using 3-port servo valve. It includes dynamic pressure feedback as a inner loop and position feedback as a outer loop.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1122-1126
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• 1991

As microcomputers have become widespread and the high speed solenoid valves have been developed, digitally controlled hydraulic systems are used in many applications. This study deals with position control of hydraulic cylinder operated by two port 3-way high speed solenoid valve using a self-learning strategy. This was done by developing a control algorithm for the microcomputer which always automatically adjust the length of control pulse to the optimum value in accordance with the error regardless of changes in the operating condition and physical differences between components. Tests carried out in the laboratory indicate that a positional accuracy could be improved.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.663-668
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• 1986

State variables of an observer were made use of to realize the optimal position control of a hydraulic servosystem with the inherent nonlinearities. The range of eigenvalues of an observer suitable for the hydraulic servosystem was investigated through computer simulation. The effect of direct state feedback of hydraulic servosystem was compared with that of estimated state feedback using observer to ascertain the possibility of performance increase using observer.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.669-672
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• 1986

The velocity control of hydraulic servo system with heavy load and large capacity was investigated through the linear analysis and digital computer simulation. Each part of the nonlinear hydraulic servo system was mathmatically modelled. The result of linear analysis and computer simulation showed that the use of derivative of load pressure as a feedback signal is effective in velocity control.