Research On The Control System Of Unmanned Survey Ship Based On GIS

Depth measurements and quality monitoring, the most critical applications forwaters, are of great significance for the waterway development. It has strong practicalsignificance to develop a mapping system of completely independent, good flexibility,low cost, high accuracy for the surveying operation on inland waterways. This paperdesigns an unmanned survey ship which is equipped with GPS, ultrasonic sensor,depth gauge, and other instruments. It can be widely applied to waters surveyingprojects with functions of real-time GPS data acquisition, automatic navigation andobstacle avoiding, ship track display and data storage.Firstly, this paper presents the basic principles and concepts of GPS. The data weneed are in coordinate of local place, but GPS output is in the internal coordinate,forasmuch, the two coordinates must be converted before controlling. In this paper themost important work is to establish transformation mathematical models, also, theexact coordinates transformation is accomplished through the programming.Secondly, automatic navigation is a key problem for the ship. The PID controllerhas been widely used in industrial settings, mainly applicable to a precise mathematicalmodel of the linear system, but as a result of flow velocity and other objective factors,individual PID controller is not sufficient to make the ship accurately track thenavigation line. Artificial potential field algorithm is used in the robot path planningwhich can realize avoiding obstacle, finding the optimal path autonomously. Thispaper combines the artificial potential field method with PID controller, and improvesthe artificial potential field function, which not only makes the unmannedmeasurement ship find the shortest path from the predetermined course and avoidspecial position obstacles, but also realize the critical track keeping. All these stepshappen without human controls. Ship steering gear control is the most important partof the navigation control system. The steering gear is the execution mechanism ofnavigation algorithm and directly affects the precision of navigation.The system can realize rapidly precise control of steering gear by using a batteryto supply actuator and position the actuator degree via counting infrared pulse. Thepower goes through the chopper circuit to drive a servo motor, which changes rotationof a steering engine into a chain linear motion. Again, developing a humanization and convenient operating interface is also akey research. Geographic Information Systems (GIS) set the current most advancedtechnology as a whole, which includes graphics, images, geography, remote sensing,mapping, artificial intelligence, computer science. With VC6.0as a development tool,a software is designed to develop GIS aiming at greatly improving the measurementwork which contains real-time GPS data acquisition, ship track display, serialcommunication, GPS coordinate conversion and sensor parameters display.Finally, field measurement experiments are constructed in order to verify thefeasibility of the designed system. Results show that this unmanned ship, which hashigh accuracy, good flexibility, and completely independent characteristics, could meetthe requirements of the surveying and mapping projects, and can be widely used infairway surveying engineering.