• 한국항공운항학회지
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• 제23권2호
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• pp.63-68
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• 2015

This paper presents the algorithm for envelope protection of helicopters. The algorithm consists of two feedback control loops: inner loop and outer loop. As an inner loop control, model following control is designed to meet the ADS-33 handling qualities specification by minimizing the tracking errors between the responses of the actual model and those of the command filter. In order to implement envelope protection, saturation limiter is imposed to command channels in command filter, whose limits are computed corresponding to the envelope limit. Fast model predictive control is designed as an outer loop control to deal with saturation constraints generated by the inner loop envelope protection and also imposed by outer loop envelope protection variables. Simulation results show that the proposed algorithm yields good envelope protection performance.

• Journal of Power Electronics
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• 제13권2호
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• pp.197-205
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• 2013

In energy injection resonant AC-AC converters, due to the low frequency effect of the AC input envelope and the low energy injection losses requirement, the constant and steady control of the high frequency AC output envelope is still a problem that has not been solved very well. With the aid of system modeling, this paper analyzes the mechanism of the envelope pit on the resonant AC current. The computing methods for the critical damping point, the falling time and the bottom value of the envelope pit are presented as well. Furthermore, this paper concludes the stability precondition of the system AC output. Accordingly, an optimal control method for the AC output envelope is put forward based on the envelope prediction model. This control method can predict system responses dynamically under different series of control decisions. In addition, this control method can select best series of control decisions to make the AC output envelope stable and constant. Simulation and experimental results for a contactless power transfer system verify the control method.

• Architectural research
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• 제7권2호
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• pp.47-54
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• 2005

A photoelectric dimming control system for a small private office space with a double skin envelope system was analyzed for the purpose of examining optimum control performances under a variety of daylight conditions. Computer simulations were performed for the three different photosensor types positioned at the center of ceiling in the space. They were applied in both a south and north-facing room. Daylight conditions were a fixed horizontal venetian blind on an external envelope and a retractable shading device on an internal envelope under a clear, intermediate and overcast sky at different times of a day and year. Partially-shielded photosensors provided good control performances providing the required electric light output under clear and intermediate sky conditions. Unshielded photosensors failed to provide necessary illuminance levels producing less electric output and fully-shielded photosensors generally provided excessive light output. Reasonable electric lighting energy savings were achieved except under overcast sky conditions where the control system did not contribute to energy savings due to the less daylight through envelopes. The retractable shading device covering 50% of the internal envelope reduced energy savings up to 19.62%, but the workplane illuminance levels were maintained within recommended ranges. The coefficients of determination between workplane illuminance and photosensor illuminance due to daylight ranged from 0.74 to 0.98. Partially-shielded conditions provided best correlations and the north-facing room yielded stronger correlation than the south-facing room.

• 한국해양공학회지
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• 제30권2호
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• pp.134-140
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• 2016

An envelope protection system is a control system that allows a submarine to operate freely using its own operational envelope without exceeding the structural limit, dynamic limit, and control input limit. In this paper, an envelope protection system for the pitch angle of a submarine is designed using a dynamic trim algorithm. A linear quadratic regulator and artificial neural network are used for the true dynamics approximation. A submarine maneuvering simulation program developed using experimental data is used to validate the designed envelope protection system. Simulation results show the effectiveness of the designed envelope protection system.

• International Journal of Aeronautical and Space Sciences
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• 제12권3호
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• pp.241-251
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• 2011

Most large commercial aircrafts and high performance military aircrafts use fly-by-wire (FBW) or fly-by-light systems to improve their controllability, comfort, and safety. A flight envelope protection technique is used with flight control systems utilizing the FBW technique. Such flight envelope protection systems prevent these aircraft from exceeding the structural/aerodynamic limits and control their surface limits. This is accomplished by predicting the values of the future state variables and adaptively compensating the control action. In this study, the conventional dynamic trim algorithm of the flight envelope protection is modified to increase the method accuracy and to handle cases with multiple variables. Numerical simulation is also performed to verify the performance of the proposed method.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.97-100
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• 2005

This paper proposes a linearization method that is to control the operating point of a class AB amplifier according to its output power. The proposed linearization method is presented in this paper and the performance test results using two-tone signal are presented also.

• 설비공학논문집
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• 제24권8호
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• pp.627-635
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• 2012

This study aims at developing an artificial neural network(ANN)-based predictive and adaptive temperature control method to control the openings at internal and external skins, and heating systems used in a building with double skin envelope. Based on the predicted indoor temperature, the control logic determined opening conditions of air inlets and outlets, and the operation of the heating systems. The optimization process of the initial ANN model was conducted to determine the optimal structure and learning methods followed by the performance tests by the comparison with the actual data measured from the existing double skin envelope. The analysis proved the prediction accuracy and the adaptability of the ANN model in terms of Root Mean Square and Mean Square Errors. The analysis results implied that the proposed ANN-based temperature control logic had potentials to be applied for the temperature control in the double skin envelope buildings.

• 한국전자파학회논문지
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• 제17권2호
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• pp.129-133
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• 2006

사전 왜곡형 선형 증폭기는 회로가 간단하고 제작 비용이 적은 장점이 있으나, 상호 변조 왜곡 hump 특성 때문에 낮은 출력 전력에서 상호 변조 왜곡 특성이 나빠지는 단점이 있다. 본 논문에서는 출력 전력에 따라 전력 증폭기의 바이어스를 제어하는 방법으로 이와 같은 단점을 개선하였다. AB급 바이어스를 사용한 16 W급 사전 왜곡형 전력 증폭기에 본 논문에서 제안한 방법을 적용한 결과, 넓은 출력 전력 범위에서 약 10 dB의 3차 상호변조 왜곡 특성이 개선됨을 확인하였다.

• 제어로봇시스템학회논문지
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• 제21권3호
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• pp.199-209
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• 2015

This paper presents a model predictive control (MPC) approach to control the steering angle in an autonomous vehicle. In designing a highly automated driving control algorithm, one of the research issues is to cope with probable risky situations for enhancement of safety. While human drivers maneuver the vehicle, they determine the appropriate steering angle and acceleration based on the predictable trajectories of surrounding vehicles. Likewise, it is required that the automated driving control algorithm should determine the desired steering angle and acceleration with the consideration of not only the current states of surrounding vehicles but also their predictable behaviors. Then, in order to guarantee safety to the possible change of traffic situation surrounding the subject vehicle during a finite time-horizon, we define a safe driving envelope with the consideration of probable risky behaviors among the predicted probable behaviors of surrounding vehicles over a finite prediction horizon. For the control of the vehicle while satisfying the safe driving envelope and system constraints over a finite prediction horizon, a MPC approach is used in this research. At each time step, MPC based controller computes the desired steering angle to keep the subject vehicle in the safe driving envelope over a finite prediction horizon. Simulation and experimental tests show the effectiveness of the proposed algorithm.

• Animal cells and systems
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• 제2권3호
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• pp.341-349
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• 1998

To analyze the effects of surfactants on the biosynthesis of galactolipid and the composition of fatty acids, the chloroplast envelope and thylakoid membrane were cultivated in medium treated with anionic surfactants, such as linear alkylbenzene sulfonate (0.002%, LAS), a-olefin sulfonate (O.01%, AOS), and sodium lauryl ether sulfate (0.08%, SLES), respectively. During the cultivation, the chloroplast envelope and thylakoid membrane were isolated from the cells collected at the early and middle phase of the culture and the contents of their fatty acid composition were compared with the control. When treated with surfactants, the contents of total lipid MDGD methylesters, and DGDG methylesters decreased significantly when compared with the control. It was also confirmed that more unsaturated fatty acids were involved in the biosynthesis of galactolipid. The fatty acids utilized in the biosynthesis of MGDG were in the chloroplast envelope and in the control, and linoleic acid in LAS, linolenic acid and oleic acid in AOS, and linolenic acid and oleic acid in SLES. The fatty acids in the biosynthesis of DGDG were linolenic acid and oleic acid in the control linolenic acid and stearic acid in LAS, oleic acid and linolenic acid in AOS, oleic acid and linolenic acid in SLES. In the thylakoid membrane, the major fatty acids in the biosynthesis of MGDG were linolenic acid and oleic acid in the control, oleic acid and linolenic acid in LAS, linolenic acid and linoleic acid in AOS, linolenic acid and palmitoleic acid in SLES. The fatty acids in the biosynthesis of DGDG were linolenic acid and oleic acid in the control, oleic acid and linolenic acid in LAS, linolenic acid and linoleic acid in AOS, palmitoleic acid and oleic acid in SLES.