• Journal of Power System Engineering
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• v.15 no.2
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• pp.69-77
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• 2011

In this paper, an optimal PID sliding mode controller is proposed for the position control of electro-hydrostatic actuator(ERA) systems with system uncertainties and saturation in the motor. An ERA prototype is developed and system modeling and parameter identification are executed. Then, optimal PID and optimal anti-windup PID controller are designed based on identified system model by using optimization toolbox in MA TLAB/Simulink and the performance of the two control systems are compared by experiment. It was found that the optimal anti-windup PID control system has better performance than the optimal anti-windup PID control system.

• 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.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1062-1070
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• 1995

The study deals with controlling the velocity of hydraulic motor with PI controller through the control of displacement pump which has higher efficiency than valve-controlled system. This was done as follows. First, we modified original displacement pump and designed this electrohydraulic puma system. Second, after experimenting static and dynamic characteristics, we identified system parameter of approximated model. Lastly, to control the velocity of hydraulic motor we controlled the angle of the swash plate of displacement pump. Test carried out in the laboratory shows that transient and steady state response could be improved by PI controller reducing power loss.

• Journal of Drive and Control
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• v.14 no.3
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• pp.50-57
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• 2017

Recently, methods of verification for electro-hydraulic servo controllers are various and the required number of testing controllers is continuously increasing in some specific systems. In this study, a PCB-based electronic simulator of hydraulic actuators is designed and developed to simplify test set-up for controllers and to facilitate alteration for characteristics of the simulator. Several features to reduce required time and manpower for verifying controllers are described. Especially, the simulator is considerably efficient to examine some controllers for different hydraulic actuators in a test. Response characteristics of the simulator are compared with those of real actuators to demonstrate validity of this method. Results reveal utilizing the designed simulator for inspecting controllers is equally effective as using hydraulic actuators.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.321-325
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• 1988

The objective of this study is to develop a microcomputer-based adaptive controller for an electro hydraulic velocity control system subjected to the variation of system parameters. The step response performance of the system with the adaptive controller is investigated for the variation of the external load torque, the moment of inertia and the reference inputs, and compared with that obtained by PID controller whose gains are constant. The experimental results show that this proposed model reference adaptive controller is robust to the variation of system parameters and yield much better control performance compared with the conventionel PID controller.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.693-697
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• 1990

A position control system is developed for an electro-hydraulic servo actuator with coaxial rotary spool, where the actuator is controlled by stepping motor. The position control system is utilized to develop the wireless remotely controlled crane system. And remote engine control system is also developed. Finally, to show the validity of this system, some experimental results and field test results am presented.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.868-876
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• 1995

This study deals with a position control of an electro-hydraulic servo system which consist of cylinder and high speed on-off valves operated by microcomputer. The merits of PWM control of hydraulic equipment are the robustness of the high spee on-off valve, its low price and the direct control without D/A converter. In the PWM control of high speed on-off valve, the time lag and switching time existing between the input and output signals of valve are considered as demerit points. To get analytical results, the effects of these demerits have to be clarified in detail. The object of this study is to propose a mathematical model for the behavior of high speed on-off valve and to get analytical results of this system. The dynamic characteristics of this system is examined by digital computer simulation analytically and compared with experimental results to varify the proposed mathematical model.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.801-805
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• 2008

Today, hydraulic systems play an important role in modern industry for the reasons that hydraulic actuator systems take many advantages over other technologies with high durability and the ability to produce large forces at high speeds. In recent years, electro-hydraulic actuator systems, which combine electric and hydraulic technology into a compact unit, have been adapted to a wide variety of force, speed and torque requirements. Moreover these systems resolve energy consumption and noise problems characteristic existed in the conventional hydraulic systems. Therefore, these systems have a wide range application fields especially in an excavator. So the purpose of this paper is to demonstrate efficiency of the energy saving and present some control algorithms which apply to electro-hydraulic actuator system in the bucket of the excavator. Experiments are carried out to verify the effectiveness of the proposed system with various external loads as in real working conditions.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2581-2583
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• 2000

The performance of the electro-hydraulic servo control mechanism and the electronic servo controller in the steam turbine control system affect greatly upon overall system performance. We have succefully carried out a retrofit project of a 200MW steam control system recently. Here we introduce some acquired knowledge and experience about the servo control system which we actually configured in the project.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.134.4-134
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• 2001

Hydraulically driven manipulators are superior to electrically driven ones in the power density and electrical insulation. But an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous field tasks such as the maintenance task of high voltage active electric line or the automatic excavation task by hydraulic excavator. In this report, we propose robust force control algorithm, which can be applied to the real field task such as the construction field, nuclear plant and so on. Proposed force controller has the same structure as that of disturbance observer for position control. The difference between force and position disturbance ...