Design auto trajectory of passenger ship in variation of sea condition in line Ketapang - Gilimanuk of Bali strait, Indonesia

Abstract

The fleet of ferry ships crossing in the Bali Strait between Ketapang - Gilimanuk is relatively old, where when the waves are quite large and the current is strong enough the ships cannot go directly to Ketapang or vice versa. In order for the ship to reach its destination, it needs the right trajectory based on sea conditions. An automatic control system algorithm is proposed to perform an auto trajectory system. New trajectory is created base on the sea conditions. The auto trajectory system consists of steering and speed control system. The study was done by computer simulation and using of Matlab software. Simulations were carried out for various conditions of sea current speed of 3-7 knots and waves with in height of 1-1.5 meters. The auto trajectory system used of adaptive fuzzy control system to determine the proportional - integral and - derivatives (PID) gain controller. The rules in fuzzy control use the Sugeno type. The performances of control to meet IMO standards and produced 5 trajectory models for various current and wave heights, in both of the direction from the north (Java Sea) and from the south (Australian sea). The fuzzy control can keep the ship on its trajectory with the largest error of 3.93 meters when the sea current is 7 knots from the south and the sea wave height is 1.5 meters.