The use of microcontrollers to change control of Gozo ferry boats from two stick to a single stick control system

Abstract

Ferry boats with frequent short trips are required to be highly maneuverable and so the control stick movement has to be mentally easy and correspond to the required actions of the ferry. Currently, the three modern Gozo Ferry Boats used by Gozo Channel Company Limited employ a two-stick control system in order to control their four azimuth thrusters to obtain the required ship maneuvers. The proposed control system described in this dissertation makes use of a single 4-axis joystick to achieve all the control combinations required to maneuver such ferries. This would essentially reduce the amount of shifting required and would enable the maneuvering of the ferry boat with minimal effort. A watercraft model that can be controlled remotely through radio control was constructed, such that through the combination of microcontrollers and sensors on the stick, a working proposition that proves the point that a single control stick is more intuitive than the twostick system available on the Gozo Ferry Boats is presented. Through the use of a single 4-axis joystick, the watercraft model can move ahead and astern, move sideways, rotate on the same spot and perform a combination of these possibilities. All these combinations were achieved through the use of two dc propulsion motors and two servo-controlled rudders located at the bow and stern of the model ship. Two Proportional-Integral speed loops, obtaining their feedback from optical rotary speed encoders, were implemented so as to regulate and control the speed of the two dc brushed motors used. A Global Positioning System (GPS) receiver and other navigational sensors were also incorporated in the system, such that the watercraft model could be navigated from one location to another autonomously. A number of waypoints, which can be set by the user through software, control the trajectory of the model when this system is engaged. This can be used to override the captain when necessary. The system was thoroughly tuned and tested so as to evaluate its performance and confirm its compliance with the project‟s objectives. Some possible future enhancements that can be merged into the system in order to add more features and achieve better accuracy are also proposed in this dissertation.