• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.468-471
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• 1997

In this paper, we investigate the time-sampling effects on the digital implementation of singular perturbation based STT autopilot with excellent performance and propose a compensation method for the time-sampling effects. In digitization of analog STT autopilot, it is found that the stability margin of the fast dynamics is mostly affected to lead to rapid decrease. Under the this analysis, a composite digital controller with additional compensator for fast dynamics is proposed to improve the time-sampling effect and a simulation verifies the result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.619-621
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• 2005

This paper proposes apractical design method for ship-to-ship missiles' autopilot. When the pre-designed analogue autopilot is implemented in digital way, theygenerally suffer from severe performance degradation and instability problem even for a sufficiently small sampling time. Also, aerodynamic uncertainties can affect the overall stability and this happens more severely when the nonlinear autopilot is digitally implemented. In order to realize a practical autopilot, two main issues, digital implementation problem and compensation for the aerodynamic uncertainties, are considered in this paper. MIMO (multi-input multi-output) nonlinear autopilot is presented first and the input and output of the missile are discretized for implementation. In this step, the discretization effect is compensated by designing an additional control input. Finally, we design a parameter adaptation law to compensate the control performance. Stability analysis and 6-DOF (degree-of-freedom) simulations are presented to verify the proposed adaptive autopilot.

• 대한전기학회논문지
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• 제41권3호
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• pp.281-291
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• 1992

This paper deals with the digital autopilot implementation for a launch vehicle. We propose a hardware and software system for digital autopilot implemented by microprocessor. The hardware system designed in this paper consists of CPU and memory board with 80286 MPU and 80287 NPU and I/O interface with A/D and D/A converters. The software system developed is composed of power-on self-test program, initializing program, interrupt service program, and control program. The performance of the overall system controlled by the digital autopilot implemented in this paper is evaluated via real-time simulations, which show that the control performances are satisfactory.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.82-86
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• 1989

In this paper, digital autopilot design methods are investigated and a new method is suggested in order to improve existing problems. The method is based on .delta. transform (1) and overcome numerical problems occurring in the process of discretization. We illustrate design procedures using .delta. transform and suggest a hardware and software structure for digital autopilot implemented by microprocessor.

• 한국항해학회지
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• 제9권2호
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• pp.13-26
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• 1985

The purpsoe of automatic steering system is to keep the ship's course stable with the minimum course error and rudder angle, and there have been a number of studies as to the optimal design and adjustment of the autopilot. Recently, modern control theories are being used widely in analyzing and designing the system. When a ship is at sea, autopilot installed on the ship plays an important role, particularly in the respect of economic aspects, that is, when the design and the adjustment of adjustable parameters are not conducted perfectly, the amount of loss in energy and the extension of sailing distance become large. Therefore the optimal design and adjustment of a autopilot are very important. Though P.I.D type autopilots are widely spread and generally used in modern ships, the suitability and the adjusting method are not clarified. In this paper the authors considered the stabilaity and the economical efficiency of the P.I.D. type autopilot and investigated various facts which should be considered at the time of designing and using the P.I.D. type autopilot through the digital computer simulation.

• 전자공학회논문지SC
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• 제37권3호
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• pp.33-43
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• 2000

특이섭동 기법을 이용한 제어 시스템의 설계가 가능하기 위해서는 무엇보다도, 빠른 동력학의 안정성이 중요하다. 그런데, 제어기의 디지털 구현으로 인하여, 이 빠른 동력학의 안정도가 영향을 받을 수 있다. 본 논문은 최근의 개발된 우수한 성능의 특이섭동 기반의 STT 자동조정장치(autopilot) 설계의 경우를 들어 이러한 특이섭동 기법에 기반하여 설계된 제어 시스템에 대한 샘플링 영향을 조사하고 개선된 제어기 설계의 예를 제시하여, 특이섭동 기반 제어 시스템 에 대한 샘플링 영향 분석의 필요성 및 유효성을 밝혔다.

• 한국항공우주학회지
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• 제36권11호
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• pp.1104-1111
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• 2008

고등훈련기급에 탑재되어 있는 전기식 비행제어계통 (digital fly-by-wire flight control system)은 통합 다기능 감지기(IMFP : Integrated Multi-Function Probe)를 이용하여 항공기의 고도/속도/받음각 정보를 획득한다. 고등훈련기에는 3개의 IMFP가 장착되어 있으며, 이는 비행제어법칙에 3중의 공기정보를 제공한다. IMFP로부터 제공된 3개의 공기 정보는 중간 값을 채택하여 보다 신뢰성 있는 정보를 비행제어법칙에 제공한다. 초음속 비행시험 결과, 초음속 영역에서 발생하는 잡음이 포함된 IMFP로 인하여 고도유지모드 자동조종장치를 작동시켰을 때, 세로축으로 진동현상이 발생하였다. 이러한 현상은 자동조종장치를 이용하여 비행을 할 경우, 항공기 안정성 및 조종성을 저해할 수 있다. 본 논문에서는 초음속 영역에서 발생하는 IMFP 잡음정보가 자동조종장치에 영향을 미치지 않도록 비행제어법칙을 설계하였으며, 제어법칙설계 및 귀환이득을 조율하여 선회비행 시에 피치자세각 유지모드를 개선하였다. 설계된 비행제어법칙은 비실시간 시뮬레이션 및 비행시험을 통하여 검증하였다.

• 대한기계학회논문집A
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• 제20권8호
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• pp.2449-2457
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• 1996

This paper presents a design method for autopilot control system in course change to the specified direction based on a robust digital servo controlmelthod incorporating the concept of the annihilator polynormial. The mathematicalmodel of ship turning motion is very complex in the view of practical control because it has time varying parameters, nonlinear and dead time terms. To apply the digital servo control method based on computer control, the model is linearized at an equilibrium point and discretized with appropriate sampling time. The control algorithm was evaluated on the basis of computer simulation for a model ship and the practical experiment was carried out with an image processing method for measurement of ship position in a water tank. The results of overall experiments show that the proposed control method will be one of good way to keep a track plotted in the map.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.342-345
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• 2005

This paper describes dynamics analysis of a small training boat and a new type of ship's autopilot not only to keep her course but also to reduce her roll motion. Firstly, statistical analysis through multi-variate auto regressive model is carried out using the real data collected from the sea trial on an actual small training boat Sazanami after the navigational system of the boat was upgraded. It is shown that the roll motion is strongly influenced by the rudder motion and it is suggested that there is a possibility of reducing the roll motion by controlling the rudder order properly. Based on this observation, a new type of ship's autopilot that takes the roll motion into account is designed using the muti-variate modern control theory. Lastly, digital simulations by white noise are carried out in order to evaluate the proposed system and a typical result is demonstrated. As results of simulations, the proposed autopilot had good performance compared with the original data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1076-1079
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• 1993

A fuzzy digital controller is combined an autopilot system for compensating the cross coupling effect of the induced roll due to the dynamic characteristic of three fin torpedo. However the utilization of fuzzy chip has many interfacing problems with typical microprocessors of the guidance and control unit. Since a fuzzy digital controller on a microprocessor uses a finite word length A/D converters arul D/A converters, ADC and DAC may generate nonlinear effects such as deadband and limit cycle phenomena. In this paper, the robustness of fuzzy digital controller is tested with ADC a finite word length.