• 한국전자통신학회논문지
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• 제18권3호
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• pp.509-520
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• 2023

항공기에서 소형 제트기까지 항공기에 적용되는 플라이 바이 와이어 시스템의 구성 및 특성등에 대하여 기술 하였다. 특히 비행조종컴퓨터 다중화 방안과 데이터 통신 버스, 조종면 작동기, 플라이 바이 와이어 시스템을 통하여 적용되는 제어 법칙 등에 대한 기술 개발 동향에 대해 고찰하였다. 전투기에 처음 적용되었던 플라이 바이 와이어 시스템은 여러 가지 장점으로 인해 까다로운 인증과정을 거쳐 민간 항공기에까지 적용되었고, 최근에는 소형제트기까지 적용 범위가 확장되고 있으며 미래에는 대부분 플라이 바이 와이어 항공기가 주를 이룰 것으로 전망된다.

• Journal of Mechanical Science and Technology
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• 제19권3호
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• pp.778-791
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• 2005

A novel pneumatic artificial muscle actuator (PAM actuator), which has achieved increased popularity to provide the advantages such as high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks, has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. Then it is not easy to realize the performance of transient response of pneumatic artificial muscle manipulator (PAM manipulator) due to the changes in the external inertia load with high speed. In order to realize satisfactory control performance, a variable damper-Magneto­Rheological Brake (MRB), is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control method brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity, uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control method and without regard for the changes of external inertia loads.

• 드라이브 ㆍ 컨트롤
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• 제13권4호
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• pp.1-6
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• 2016

Typically, the seat of an automotive vehicle generally includes a horizontal seat-cushion portion and a vertical seat-back portion that is operatively connected to the seat-cushion portion. The seat may include a recliner for the reclining of the seat-back portion relative to the seat-cushion portion by the seat occupant. An energy absorber or damper can also be provided for the seat-back portion. Because the recliner is configured to be released at a relatively high speed, and it results in an impact at the end of a folding stroke, the damper needs to dissipate energy as the seat back moves with respect to the seat cushion; therefore, the role of the seat damper in the automotive-seat design is important. In this paper, the mechanism of an hydraulic-type automotive-seat damper is investigated, and the torque characteristic is simulated according to the design-parameter variations such as the orifice area and the working-fluid properties.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.108-115
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• 2014

In this study, experimental approaching method was applied under and single-cylinder engine to research the performance of direct needle-driven piezo injector (DPI) for CR direct-injection. As key-point factor of this DPI that relies on direct-acting operating of injector needle, unlike conventional hydraulic-servo, its nozzle needle can be directly driven by piezo actuator. Thus, effect of direct-acting injection of DPI on diesel combustion and emission characteristics was investigated under common-rail single-cylinder direct-injection engine, equipped with three different driving mechanism, including indirect-acting solenoid, piezo and DPI system. As main results, it found that a direct-acting piezo injector has higher of IMEP. And it has higher heat release rate during premixed combustion and mixing controlled combustion phase due to its higher heat release, even though nitrogen oxide (NOx) formations were increased slightly.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.871-876
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• 2005

Currently, the marketable truck has the cab tilting system which highly absorb the vibrations and impacts of cab. The cab tilting system is equipped with the hydraulic system for maintenance and inspection of truck. And it is very important to improve the user's feeling of driving and convenience. To have the better performance, it is important to confirm the dynamic characteristics of each parts of the system. In this study, a mathematical model of the system was derived and the parameters in the model were identified from experimental data. The results of the simulation were compared with those of experiments. These results of the computer simulation and experiments show that the proposed analysis can be applied effectively to design the system. Our results can be utilized for the future research to improve the capability of the truck cab tilting system.

• 한국소음진동공학회논문집
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• 제27권2호
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• pp.168-174
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• 2017

In this work, a piezostack single-stage valve (PSSV) system is proposed and its control performance is experimentally evaluated at high temperature up to $150^{\circ}C$. In order to achieve this goal, a PSSV system is designed and operating principle and mechanical dimensions are discussed. A displacement amplifier and an adjust bolt are used to generate target displacement and to compensate thermal expansion. Then, an experimental apparatus is constructed to evaluate control performance of the PSSV system. The experimental apparatus consists of a heat chamber, a hydraulic circuit, a pneumatic circuit, pneumatic-hydraulic cylinders, thermal insulator, electronic devices, sensors, data acquisition (DAQ) board and a voltage amplifier. The flow rate and displacement control performance of the valve system are evaluated via experiment. The experimental results are evaluated and discussed at different temperatures and frequencies showing the controlled flow rate and spool displacement.

• 소음진동
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• 제6권2호
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• pp.215-224
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• 1996

Active vibration control is generally used to reduce vibration level by the actuators based on measured signal. Dynamic properties of a structure can be easily modified by the active vibration control, so that the vibration level may be effectively reduced to the magnitude below the allowable limit over a wide frequency rangs. In this paper, an instantaneous optimal control algorithm including acceleration feedback is presented for the active vibration control of large structures considering facts that the acceleration response can be easily measured, but the displacement and velocity response are obtained by numerically integrating the measured acceleration response with some errors. The adverse effect of the time delay is overcomed by taking into account the dynamic characteristics of an actuator and filters in the design of controller. Performance test is carried out using a hydraulic active mass driver on a test structure$(L{\times}W{\times}H;=;1200mm{\times}800mm{\times}1600mm, about;500kg)$ supported by four columns under base excitations. It is confirmed that the vibration level of the test structure are reduced to about 1/6 near resonance.

• 한국표면공학회지
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• 제38권6호
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• pp.234-240
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• 2005

In this study, ion nitriding of a EHA pump part made of AISI 4340 steel was performed under different applied power conditions to study the relationship between dimensional changes of specimens and the type of applied power source. Microstructures and micohardness distribution at different processing conditions were also examined. Duplex surface treatment of ion nitriding with the optimum process conditions to produce the minimum dimensional variation in a EHA pump part and a TiN thin film coating by unbalanced magnetron sputtering was performed and the specimens with a duplex surface treatment were subjected to a high speed wear test to evaluate the wear performance of EHA hydraulic pump parts with various surface treatment conditions. Results indicated that uniform and continuous surface layer with a minimum dimensional variation could be obtained by ion nitriding with bipolar mode power source and much enhanced wear characteristics with a duplex surface treatment could be obtained, compared with results from ion nitriding or single-layerd TiN coating specimens.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2630-2637
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• 2020

The structure design of divertor Multi-Functional Maintenance Platform (MFMP) actuated by hydraulic system for China Fusion Engineering Test Reactor (CFETR) was introduced in this paper. The model of MFMP was established according to maintenance requirements. In this paper, Newton-Euler method and the improved virtual work principle were used, the equivalent driving force of each actuator was obtained through the equivalent Jacobian inverse matrix derived from velocity relationship among the components. The accuracy of the model was verified by ADAMS simulation. The stability control of the heavy-duty components driven by hydraulic cylinders based on Newton-Euler method and improved virtual work principle was established.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.190-198
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• 2002

Full scale durability test in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, hydraulic road simulator is used to carry out the fatigue test and the vibration test. In this paper, the algorithm and software to realize the real road profile are developed. The operation software for simultaneously controlled multi-axial road simulator is developed and the input and output data are displayed window based PC controller in the real time. Futhermore, the software to generate the real road profile are developed. The validity of the software are verified by applying the belgian road, the city road, the highway, and the gravel road. The results of the above experiment show that the real road profiles are realized well after 10th iteration.