• 한국항해학회지
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• 제19권2호
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• pp.1-12
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• 1995

The final aim of our research project is a study on assessment of automatic steering system of ships in open seas. In order to achieve this aim, we need to know the characteristics of each component of the system, and also to know the characteristics of disturbance to ship dynamics. In this paper, we provide calculation method of irregular disturbance to ships in autopilot navigation in open seas, and also show calculation examples about two kinds of ship, ore carrier and fishing boat. The disturbance consists of irregular wave and random wind. The disturbance is calculated as equivalent yaw angular velocity. Each spectrum and time history of disturbance are reasonably evaluated. Further investigation concerning to performance index of autopilot system and energy loss related to automatic course keeping, will be dealt with in another paper.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1995년도 VTS and IBS 95 The Korean Institute of Navigation 1995년도
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• pp.153-165
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• 1995

When an automatic course-keeping is introduced as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit(or telemotor unit) steering gear ship dynamics and magnetic or gyro compass. We derive the mathematical model of each element of the automatic steering system. We provide a method of theoretical analysis on propulsive energy loss related to automatic steering of ships inthe open seas taking account of the on-off mechanism of power unit. Also we paid attention to dead band mechanism of autopilot device which is normally called weather adjustment. Next we make numerical calculation of the effects of autopilot control constants ont he propulsive energy loss for two kinds of ship a fishing boat and an ore carrier. Realistic sea and wind disturbances are employed in the calculation.

• Journal of Advanced Marine Engineering and Technology
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• 제25권1호
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• pp.199-208
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• 2001

In this paper, an automatic route tracking algorithm using the position variables and the yaw angle of a ship is suggested, Since most autopilot systems paly only a role of course-keeping by integrating the gyrocompass output, they cannot cope with position errors between the desired route and real route of the ship resulted from a drifting and disturbances such as wave, wind and currents during navigation. In order for autopilot systems to track the desired route, a method which can reduce such position errors is required and some algorithms have been proposed[1,2]While such were turned out effective methods, they have a shortage that the rudder control actions for reducing the position errors are occurred very frequently. In order to improve this problem it is necessary to convert that error into the corresponding yaw angle and necessary to treat only yaw angle control problem. To do this a command generation algorithm which converts the rudder angle command reducing the current position error into they yaw angle command is suggested. To control the ship under disturbances and nonlinearities of the ship dynamics, the adaptive fuzzy controller is developed. Finally, through computer simulations for two ship models, the effectiveness of the suggested method and the possibility of the automatic route tracking are assured.

• 한국항해학회지
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• 제25권4호
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• pp.407-415
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• 2001

In the present study, irregular disturbances to ship dynamics is proposed, where irregular disturbances implying irregular wave and the fluctuating component of wind for the evaluation of automatic steering system of ship in following seas. Prediction method based on the principle of linear superposition. Irregular wave disturbances in following seas is calculated by frequency variation method. The mathematical model of each element of an automatic steering system is derived, which takes account of a few non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. Performance index is introduced from the viewpoint of energy saving, which derived from the concept of energy loss on ship propulsion. Finally, the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of control constants of autopilot on propulsive energy loss are investigated

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.853-854
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• 2006

Due to a recently developed approach to autopilot controller design for highly-maneuvering BTT (bank-to-turn) missiles, we now can derive explicitly the final-phase optimal guidance (OG) law considering the autopilot dynamics through direct use of the well-known linear optimal control theory. The proposed OG law can decrease the miss distance (MD) remarkably with small acceleration and roll rate profile at the time of interception.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.48.3-48
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• 2001

A gain-scheduled autopilot design for a bank-to-turn (BTT) missile is developed by using the Linear Matrix Inequality (LMI) optimization technique and a state-space lineal interpolation method. The missile dynamics are brought to a quasilinear parameter varying (quasi-LPV) form. Robust linear control design method is used to obtain state feedback controllers for the LPV systems with exogenous disturbances at the frozen values of the scheduling parameters. Two gam-scheduled controllers for the pitch axis and the yaw/roll axis are constructed by linearly interpolating the robust state-feedback gains. The designed controller is applied to a nonlinear six-degree-of-freedom (6-DOF) simulations.

• 한국항공우주학회지
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• 제30권7호
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• pp.81-89
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• 2002

현재까지 개발된 다양한 형태의 유도법칙은, 유도개념에 따라 추적방식, 미사일과 표적에 의해 정의되는 방위각을 일정하게 유지시키는 유도법칙, 그리고 표적의 기동 예측에 기반한 유도법칙 등으로 분류할 수 있다. 본 논문에서는 이러한 개념적인 유도목적을 일반화한 유도법칙을 제안하였다. 제안한 유도법칙은 충돌삼각형 상에서 정의된 목표각을 사용하는데, 목표각은 매개변수의 설정에 따라 다양한 형태가 될 수 있다. 르야프노프 이론을 사용하여, 제안한 유도법칙은 목표각 오차의 반응이 1차 시스템과 동일함을 증명하였다. 그리고 자동조종장치의 동역학이 느릴 경우는, 목표각 오차 반응을 2차 시스템으로 모사할 수 있는 유도법칙도 제안하였다. 제안한 유도법칙의 유용성을 보이기 위하여 측정잡음을 포함한 시뮬레이션을 수행하고 결과를 제시하였다.

• 한국항공우주학회지
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• 제36권7호
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• pp.658-665
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• 2008

본 논문에서는 유도탄 응답지연을 고려한 실용적인 유도법칙을 제시한다. 유도탄의 속도벡터 방향을 조종할 수 있는 자세제어방식 autopilot을 갖는 유도탄을 고려하고, 최적제어이론을 적용하여 유도탄 응답특성에 따른 여러 가지 최적유도법칙을 유도할 수 있었으며, 실제적용 시의 문제점을 고려한 효율적인 유도법칙을 제안한다.

• 대한조선학회논문집
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• 제45권5호
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• pp.469-476
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• 2008

In this paper, it is shown that an input-output (I/O) feedback linearized controller can be designed rationally by utilizing the time-scale properties of heave and pitch for an underwater vehicle. It is assumed that the dynamics of the vehicle is restricted to the vertical plane. An output-feedback control is designed, which stabilizes steady cruising paths. It is shown that the vehicle dynamics with acceleration as output becomes minimum phase. The dynamics can be transformed into a reduced system through a kind of partial linearization and singular perturbation technique. The reduced system is not only minimum phase but also exactly I/O linearizable via feedback. The I/O dynamic characteristics of the heave and pitch modes can be made linear and decoupled. Furthermore it becomes independent of cruising condition such as vehicle velocity. This study may help for designing autopilot systems for underwater vehicles.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1063-1067
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• 1993

Fuzzy logic is applied to a roll autopilot for missiles. Fuzzy rules are made so that the response duplicates that of the conventional control law for some flight condition. A scaling factor of the fuzzy controller is then scheduled by the missile velocity and altitude information to cope with the variation of the roll dynamics from that flight condition. By computer simulations and calculation of the stability margin, it is shown that the fuzzy control is robuster than the conventional one over the flight envelope even though two control laws work similarly for some flight conditions.