Design and testing of Control and Positioning System for Underwater mining Machine

Abstract

As underwater mining machine were relied upon to perform complex operations offshore, in ever increasing water depths, positioning and control of the machine is one of the major issue where it becomes the limiting factor in the performance of the entire system. The control and data acquisition of the mining system must be flexible and capable of being configured for multi tasks with in short time and perform the operations as programmed in real-time basis. This was achieved by designing the data acquisition and control system of the mining machine based on virtual instrumentation concept using compact field point modules from National Instruments, which is an embedded real-time programmable automation controller that runs Lab VIEW <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TM</sup> Real-Time, providing the functionality, connectivity, and flexibility on a small rugged, industrial platform. Acoustic positioning system for the underwater mining machine was based on Super Short Base Line (SSBL) principle which was achieved by having one vessel-mounted transducer with the range of 4000 m and two Sub Sea transponders mounted in the machine. The positioning system provides online position status of the crawler in X, Y and Z directions with reference to the mother vessel. With the help of the acoustic positioning system and its GUI based software, it was possible to track the position of the machine in real time with reference to mother vessel during the sea test. Apart from online position tracking of the mining machine the data were recorded for post analysis. The mother vessel was equipped with Dynamic positioning system and Launching and recovery system to ease the positioning, deployment and retrieval operations of the deep sea crawling machine. The objective of the paper is to present in detail the data acquisition, control and positioning system of the underwater mining machine along with the sea test results.