• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.283-290
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• 2007

Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an Idle Speed control Actuator (ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying Computational Fluid Dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.683-692
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• 2007

Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an idle speed control actuator(ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying computational fluid dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.243-247
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• 2004

The dynamometers which had made in a long time ago could not control the input/output quantity of water minutely and was sensitive to a noise since it was controlled by an analog control method. Therefore, a fully digital controlled system was urgently required to be robust against various noises. In this paper, the new system which can control the amount of circulated water in dynamometer was developed. This system is consisted of an industrial digital type controller and a servo motor. The industrial PLC was used as a main controller for the developed system, and the actuator and servo motor were used to control the inlet and outlet valve independently. The torque signal of load cell was fed back to the main controller to regulate the diesel engines load. Generally, an input/output valve position of the old dynamometer was fixed with a proper situation for an engine output test and the torque was changed according to the time interval. However, the torque value for the dynamometer could not be constantly kept because of the variation of the input water flow and fluid characteristic. Therefore, the automatic control of an inlet and outlet valve should be performed to keep the constant torque. So, the PID control method was applied to solve this problem. Also, the development of a web-based remote control system was described in this paper. This software will give us the convenience of operation, the more efficient operations, and the reduced operator workload for operation of the dynamometer. The application results of the system have been verified at actual diesel engine field.

• Journal of the Korean Institute of Gas
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• v.24 no.5
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• pp.10-19
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• 2020

Valve leak accidents in petrochemistry plants and gas utilities cause human and property damage. The main reason why happen gas inhalation, poisoning, fire and explosion accidents is gas valve leakage. To prevent gas leakage, inspectors check the facilities in the field. And they are at risk of gas leak accidents. So we applied IoT-based risk assessment, monitoring and automatic control system. It can detect both internal and external gas leakage, do real-time monitoring of industrial valve in the plant by using hybrid sensor. As the new safety management system for industrial valve is developed, it needs method to evaluate device performance and environmental components for the system. This study is about development of method to verify performance of the explosion-proofed hybrid sensing system include gas detector and optical fiber sensor supporting wire and wireless communication.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.199-202
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• 1998

This paper describe an intelligent cruise control system for automobile. With the remarkable numerical increase of automobiles on the road, the optimized traffic flow control using the cruise control is one of the very important traffic problems to overcome the limitation of an existing road capacity. Based on this idea that minimize the fuel cost and the air pollution, and accept a driver's needs for driving, we have developed an intelligent cruise control system for vehicle. This proposed intelligent fuzzy cruise controller was successfully implemented using the fuzzy algorithm, the i80c196 μ-controller board and the throttle valve actuator. The field test results on an linear road was introduced.

• Journal of Power System Engineering
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• v.10 no.3
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• pp.97-103
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• 2006

In this study, a position trajectory tracking control algorithm is proposed for a pneumatic artificial muscle driving apparatus composed of a actuator which imitates the muscle of human, a position sensor and a control valve. The controller applied to the driving apparatus is composed of a state feedback controller and disturbance observer. The feedback controller which feeds back position, velocity and acceleration is derived from the linear model of pneumatic artificial muscle driving apparatus. The disturbance observer is designed to improve trajectory tracking performance and to reduce the effect of model discrepancy. The effectiveness of the designed controller is proved by experiments and the experimental results show that the pneumatic artificial muscle driving apparatus with the proposed control algorithm tracks given position reference inputs accurately.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.837-843
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• 2016

This paper presents a position control strategy for a pump-controlled electro-hydrostatic actuator (EHA) using feedforward control with disturbance compensation. As the disturbance observer is used to estimate nonlinear dynamics of EHA, which has valve-opening conditionals, as well as external disturbances, an additional feedforward control is adopted to achieve rapid response. The effectiveness of the proposed control strategy is verified through experiment using an EHA test bench. The proposed controller shows better tracking performance compared with a conventional PID controller.

• 기계와재료
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• v.21 no.3
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• pp.42-51
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• 2009

원자력/화력 발전소에서 사용중인 터빈출력제어장치(turbine power control device)는 유압 서보액추에이터(hydraulic servo actuator)로 구동하는 특수 스팀 밸브(steam valve)로서 터빈의 속도를 제어하고 스팀을 차단하는 기능이 있다. 대형 발전기(500~1000Mw)를 구동하여 양질의 전기를 생산하기 위해서는 발전기에 연결된 고압 및 저압터빈에 최적량의 스팀을 공급하여야 하고, 고속(화력 3600 rpm, 원자력 1800 rpm)으로 회전하는 터빈이나 스팀계통에 이상이 발생할 경우 터빈의 과속(over speed) 방지를 위하여, 즉시 터빈으로 공급되는 스팀을 차단하여 터빈을 보호해야 한다. 따라서 터빈의 속도제어와 계통의 스팀 량을 감시하여 차단하는 발전소의 특수 밸브의 신뢰성확보기술이 요구된다. 특히 원자력발전소의 경우 핵연료교환주기(약 24개월)에 밸브들을 정비 또는 교체하고 있어 이때마다 시스템과 매칭(튜닝)기술이 요구되었다. 본 연구에서는 전량 수입에 의존했던 원자력/화력 발전소의 특수 밸브인 터빈출력제어장치의 국산화 개발과 신뢰성확보기술 효과에 대하여 논하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.218-223
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• 1997

유압장치의 핵심부품인 유압 제어밸브(hydraulic control valve)는 유압펌프 등에 의하여 가압된 유압유의 압력과 유량을 제어하고 유동방향을 변화시키는 주요기능을 수행한다. 특히, 대부분의 제어밸브는 스푸울(spool)과 슬리브(sleeve)를 기본구조로 채용하고 있다. 피스톤 형상인 스푸울이 슬리브내를 왕복운동하면 스푸울과 슬리브 사이의 간극(clearance)에서는 점성유체인 유압유의 윤활작용에 의하여 원주방향으로 비대칭인 유체압력이 발생한다. 이 결과로 스푸울에 측력(lateral force)이 작용하며, 조건에 따라서는 스푸울에 작용하며, 조건에 따라서는 스푸울에 작용하는 마찰력이 증대할 뿐만 아니라 스푸울과 슬리브의 내벽에 과도한 마멸(wear)을 유방시키기도 하여 제어밸브의 성능을 크게 저하시키기도 한다. 유압공학분야서는 이를 유체고착(hydraulic locking) 현상이라고 부른다. 본 논문에서는 항공기 Flap actuator의 Selector manifold에서 사용되는 스푸울 밸브의 성능에 큰 영향을 미칠 것으로 예상되는 스프울과 슬리브 사이 간극에서의 윤활특성을 이론적으로 조사하고자 한다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.33-34
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• 2006

In this study, a prototype piezo-driven Injector. as a new method driven by piezoelectric energy, has been designed and fabricated based on the concept of inverse piezo-electric effect to overcome the major drawbacks of conventional solenoid-driven injector with a fixed and slow control of injection rate. The effects of an electric control between the solenoid valve and piezo-ceramic stack for injector needle's driving on the dynamic characteristics were usually investigated. We found that this piezo-electric actuator has the main advantage to drastically reducing the time of injector nozzle opening, as well to exert higher force output levels.