• 한국기계가공학회지
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• 제15권3호
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• pp.93-101
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• 2016

This study presents a simple genetic algorithm to systematically design a PID controller for a hydraulic positioning system operated by a proportional solenoid valve. The inverse dead-zone compensator with nonlinear characteristics is used to cancel out the dead-zone phenomenon in the hydraulic system. The object function considering overshoot, settling time, and control input is adopted to search for optimal PID gains. The designed PID controller is compared with the LQG/LTR controller to check the performance of the hydraulic positioning system in the time and frequency domains. The experimental results show that the hydraulic servo system with the proposed PID controller responds effectively to the various types of reference input.

• 한국군사과학기술학회지
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• 제16권3호
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• pp.277-284
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• 2013

In this paper, the ventilating and heating system of T-103 trainer aircraft were investigated and redesigned to improve its poor performance. The ventilation system of the trainer was designed to increase the mass flow rate of fresh air by using air intake valves. The flow-in air through the air intake valve is supplied to the cabin by the ram effect of aircraft and the propeller. And the additional heating system was installed to improve the temperature of the cabin inside. The wasted heat from the exhaust gas of the engines was used as heat source of the additional heating system by installing an heat exchanger around the exhaust nozzle. The additional fresh air and the heated air enter the cabin via two ducts mounted under the instrument panel and behind the pedal in the cabin. The additional ventilating and heating system can be controlled by the first pilot and the secondary pilot individually using the control knob equipped separately. After mounting the additional ventilating and heating system, evaluations such as inspection of parts and component, ground run-up test, in-flight test, user test, etc. were conducted. The result of the tests was sufficient to meet the requirements of the manuals, and the pilots were satisfied with the additionally mounted systems.

• 항공우주기술
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• 제9권1호
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• pp.133-142
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• 2010

발사체 추진기관은 추진제 탱크, 가압시스템, 추진제 충전/배출 시스템, 밸브 구동 시스템, 퍼지 시스템 등으로 구성되어 있다. 이 중에서 가압시스템은 온보드 실시간 제어 시스템을 포함하는 유일한 시스템으로 가장 중요한 서브시스템이다. 그러므로 추진제의 탑재량 선정 및 추진제 공급 시스템 개념설계 단계에서 가장 먼저 고려되어야 한다. 본 논문에서는 여러 타 발사체의 가압시스템에 대해 자료 조사를 수행하였고 국산화시 개발 가능한 구성을 정리하였으며, 최종적으로 시스템 중량 비교, 운용/안전/신뢰성/확장성 등을 비교 검토하여 최적 구성을 선정하였다.

• 동력기계공학회지
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• 제7권4호
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• pp.61-66
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• 2003

In this paper, the relation between displacement of piezoelectric material and electric field was proposed. FEA was introduced to predict the displacement and reaction force of plate spring attached in the piezoelectric material. The relation between displacement of piezoelectric material forced by plate spring and applied electric field were further verified by experimental investigation. Also, the flow rate of gas in piezoelectric valve was examined by experiment. Finally, the relation between electric field and gas flow was derived. Based on these results, these relations can be used in the design of mass flow controller.

• 제어로봇시스템학회논문지
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• 제7권5호
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• pp.375-383
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• 2001

As many industrial systems become more complex, it becomes extremely difficult to diagnose the cause of failures. This paper presents a failure diagnosis approach based on discrete event system theory. In particular, the approach is a hybrid of event-based and state-based ones leading to a simpler failure diagnoser with supervisory control capability. The design procedure is presented along with a pump-valve system as an example.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.633-635
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• 2009

It is a quite quality concerning to control temperature of single crystalline growth as it does when you get most of heat treating products. It is also important factor to control temperature when you make the $Al_2O_3$(single crystalline) used to artificial jewels, glass of watches, heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while you are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system for the gas mixture to improve the quality of products.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1213-1216
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• 1996

This paper describes a precise temperature control method for refrigerating and air conditioning systems. The control technique is based on the optimal servo control design method and the control algorithm is implemented on a personal computer. To control the precise temperature, two actuators such as an inverter for the compressor speed control and a stepping motor for regulating the expansion valve are used. The superheat and evaporator temperatures are chosen as the system output. So a multivariable system which has two inputs and two outputs to be controlled. The complicative model is identified by using an ARX(Auto Regressive eXogenous) model and the controller is designed by using the Matlab software.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.198-204
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• 2007

This study was carried out to develope a flow control system using to supply PR(photo-resist) in the semi-conductor manufacturing process. The features of this system are to be able to measure the high viscosity and micro-flow. To meet above study object some ideas was induced to design a new concept valve with new material, multi-cross wheel, and new sealing method etc.. As the evaluations on the developed micro-flowmeter it was enough satisfied to use at the IT industries such as photo-resist process.

• 대한기계학회논문집A
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• 제20권1호
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• pp.24-34
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• 1996

In ordaer to hold an underwater vehicle at a certain depth, buoyancy that acts on the underwater vehicle can be modulated. In this research, buoyancy that could control depth of underwater vehicle is generated by a buoyancy bag. Solenoid valves are operated by pulse with modulation(PWM) method. State equation, in consideration of the volume of buoyancy bag, pressure inside bag, and dynamic of the underwater vehicle, is derived. This system is very unstable, inculdes modelling error and nonlinearity. In depth control system, maintanance of performance is required., anainst vatiation of systerm parameter and operating depth, and designed. Through the computer simulation, performance is comparerd for each controllers.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.313-316
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• 2008

에어컨 시스템은 압축기(Compressor), 응축기(Condenser), 증발기(Evaporator)와 확장밸브(Expansion Valve)로 구성되며, 에어컨 시스템에서 과열도와 저압(증발기의 압력)은 시스템의 효율 증대 및 성능 개선과 안정성에 대하여 결정적인 영향을 미친다. 따라서, 과열도와 저압을 조절하기 위해, 각각의 압축기내의 인버터 주파수와 확장밸브의 개도 제어가 중요하며 선형과 비선형 시스템 모두에 대하여 견실한 성능을 나타내고, 외란에 대하여 강인한 성능을 보이는 퍼지 제어기를 설계한다. 본 논문에서는 과열도와 저압을 제어하기 위하여, 3대의 확장밸브와 1대의 압축기를 가진 에어컨 시스템에 대하여 다중 퍼지 제어기를 설계한다. 또한, 각 제어 플랜트에 대하여 최적의 퍼지 제어기를 설계하기 위하여 3가지 최적화 알고리즘을 사용한다. 즉, 직렬 유전자 알고리즘(Serial Genetic Algorithm; SGA)과 병렬 유전자 알고리즘인 계층적 공정 경쟁 유전자 알고리즘(Hierarchical Fair Competition Genetic Algorithm; HFCGA), 그리고 Particle Swarm Optimization(PSO)을 사용하여 다중 퍼지 제어기를 최적화하고 시뮬레이션의 결과를 비교한다.