최근 개발되고 있는 전자자기 컴퍼스를 이용한 소형어선의 항행자동화시스템을 구축하기 위한 기초 연구로서, 부두에 계류된 선박에서 각종 장비의 가동 시켰을 때 나타나는 컴퍼스 오차 변화를 측정하여 비교 분석한 결과를 요약하면 다음과 같다. 1. 목선에서 85kW의 집어등을 점등하였을 때, 조타용 자기컴퍼스는 7˚편서되었고, 전자자기 컴퍼스는 13˚~16˚ 까지 편서되는 것으로 나타났다. 2. FRP 어선에서 13OkW의 집어등을 점등하였을때, 전자자기 컴퍼스는 19˚~23˚ 까지 편동되는 것으로 나타났다. 3. 강선에서 225kW의 전력으로 각종 장비를 가동 시킬 때, 가동전과 비교하여 컴퍼스 오차의 차분은 조타용 자기 컴퍼스에서는 13˚ 편서되고, 전자자기 컴퍼스는 상갑판에서는 68˚ 편서되었고, 선수루 갑판과 조타실 및 컴퍼스갑판에서는 각각 16˚, 32˚, 20˚ 편동되어 나타났다. 4. 소형어선의 항행자동화시스템에 전자자기 컴퍼스를 활용하기 위해서는 선박내에서 사용하는 각종 장비에 의해 발생하는 컴퍼스 오차를 측정하여 적절하게 수정하여 사용해야 할 것으로 판단된다.

When an automatic course-keeping is concerned, as is quite popular in modem navigation, the closed-loop steering system consists of autopilot device, power unit (or telemotor unit), steering gear, magnetic or gyro compass and ship dynamics. In order to estimate automatic steering system of ships in open seas. 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, I provide calculation method of imposing irregular disturbance to autopilot navigation system of the ship in open seas, and also show calculation examples about fishing boat. The disturbance consists of the irregular wave and the fluctuating component of wind. Finally, The disturbances are calculated in terms of equivalent yaw angular velocity. Each spectrum and time history of disturbance are reasonably evaluated.

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

When an automatic course keeping is introduced, as is quite popular in modern navigation, the closed-loop control system consists of autopilot device, power unit, steering gear, ship dynamics, and magnetic or gyrocompass. We derive mathematical models of each element of the automatic steering system. We provide a method of theoretical analysis on the propulsive energy loss related to automatic steering of ships in the open seas, taking account of the on-off(non-linear) characteristics of power unit. Also we paid attention to non-linear element installed in autopilot device, which is normally called weather adjuster. Next we make numerical calculation of the effects of autopilot control constants on the 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.

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.