• 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.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.24-26
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• 2004

For past decade, medium voltage circuit breakers have used the spring-driven mechanical system for interrupting of electric power. However, these mechanisms have many disadvantages of high power consumption, mechanical control components and electrical switching ones for the coil current. Recently, the vacuum interrupter operated by permanent magnet actuator gives outlook on improved characteristic, higher reliability and cost price reduction as well as the feature of simple structure and few components. This paper deals with the dynamic characteristics of permanent magnet actuator used in the medium voltage distribution systems. Coupled finite element method is used to analysis the dynamic characteristics of permanent magnetic actuator and we compared with those of conventional ones.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.3
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• pp.1-6
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• 2004

In the last few years, a considerable number of studies have been made on On-Off solenoid for fluid control. But, only few attempts have so far been made at solenoid actuator for high-voltage circuit breaker. In case of the high-pressure and high-flow system like high-voltage circuit breaker, a big size of On/Off solenoid is necessary which size is proportional to control pressure and flow rate. So, it is non-effective in the view point of system optimization. In this paper, On/Off solenoid actuator with the farce amplifier connected to the solenoid rod was proposed to get a high mechanical force and a fast response time. The magnetic force and the mechanical stress distributions were analysed using finite element analysis. The performances of suggested solenoid actuator were evaluated through the experimental results and compared with the analysis results.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.104-109
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• 2001

The stress distributions of hydranlic actuator cylinder tube acting in uniform inner pressure were analysed by the boundary element method(BEM). STKM13C tube was utilized for machine structural purposes model, its inner radius was 100 mm and outer radius was 140 mm. Axial length was semi-infinite and the isoparametric element of BEM was used. Radial and tangential stresses are maximum(-20.3 MPa and 52 MPa) at the inner radius and the minimum at the outer radius of the hydraulic actuator cylinders for an industrial systems. Stress diminution ratio was about 0.6 MPa/mm. And then coincidence between the simulation techniques as exact results(Lame' equation) and finite element method(FEM) is found to be fairly good, showing that the proposed analysis by BEM is reliable.

• Transactions of the Society of Information Storage Systems
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• v.5 no.1
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• pp.1-7
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• 2009

Recently, the growing market demand for small and slim mobile phone cameras requires the size reduction of the camera module. In this paper, an auto-focusing actuator for camera phones is proposed by converting the rotational motion by a rotary VCM actuator into the linear motion using a novel cam structure. This new concept for auto-focusing module enables the reduction of the module thickness and low power consumption. This paper presents the theoretical analysis and optimal design for VCM actuator, cam structure and preload spring. Finally, the experimental results using a prototype with the size of $9.9{\times}9.9{\times}5.9\;mm^3$ are compared with the theoretical predictions.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.1
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• pp.1-6
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• 2006

A servo actuator with a valve using MR (Magneto-Rheological) fluid is proposed for fluid control systems. The MR fluid is well known as a functional fluid whose apparent viscosity is controlled by the applied magnetic field strength. The pressure in the MR cylinder can be controlled by the applied magnetic field strength. Good points of the MR cylinder are more simple, compact and reliable structure than a conventional oil hydraulic cylinder. The experimental results show that the MR cylinder could be used as a servo actuator.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.1
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• pp.1-9
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• 2011

The main design factors which effect on operating speed of linear actuator for valve operation are mass of plunger, electromagnetic motive force, inductance, and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. This paper presents a speed increasing method of linear actuator using a solenoid design method by some governing equations which are composed of electromagnetic theory and empirical knowledge and permanent magnets as assistant material, and proved the propriety by experiments.

• Proceedings of the KIEE Conference
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• summer
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• pp.1040-1042
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• 2004

For past decade, medium voltage circuit breakers have used the spring-driven mechanical system for interrupting of electric power. However, these mechanisms have many disadvantages of high power consumption, mechanical control components and electrical switching ones for the coil current. Recently, the vacuum interrupter operated by permanent magnet actuator gives outlook on improved characteristic, higher reliability and cost price reduction as well as the feature of simple structure and few components. This paper deals with the dynamic characteristics of permanent magnet actuator used in the medium voltage distribution systems. Coupled finite element method is used to analysis the dynamic characteristics of permanent magnetic actuator and we compared with those of conventional ones

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.239-245
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• 2013

Modern electric controlled valves are demanded that its solenoid actuator should be smaller size, lighter weight, lower consumption power, and higher response time. For achieving these purposes, the major design factors of solenoid actuator such as magnetic flux density, coil turn numbers, plunger size, bobbin dimension, and etc. are must be optimized. In this study, for optimal design of high speed solenoid actuator for hydraulic servo valve operation, we draw up governing equations which are composed by combination of electromagnetic theories and empirical knowledge, and deduct the values of major design factors by use of them. For more increase the operating speed, voice coil are used as main armature in manufacturing of prototype actuator. And, we have proven the propriety of the governing equations and speed increasing method by experiments using the hydraulic valve assembly adopted the prototype of solenoid actuator.

• Smart Structures and Systems
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• v.24 no.2
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• pp.183-191
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• 2019

A piezoelectric paper feeder actuator using Micro Virtual Roller (MVR) is proposed, designed, fabricated and tested. This actuator can drive a sheet of paper forward or backward without any mechanical parts, such as the costly and heavy rollers used in traditional paper feeders. In this paper feeder actuator, two vibrating stators which produce traveling waves are used to drive the paper. The vibrations of the stators are similar to those of piezoelectric motors and follow a similar procedure to move the paper. A feasibility study simulated the actuator in COMSOL Multiphysics Software. Traveling wave and elliptical trajectories were obtained and the dimensions of the stator were optimized using FEM so that the paper could move at top speed. Next, the eigenfrequencies of the actuator was determined. Experimental testing was done in order to validate the FEM results that revealed the relationships between speed and parameters such as frequency and voltage. Advantages of this new mechanism are the sharp decrease in power consumption and low maintenance.