||ALSTOM Power Conversion
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The basic purpose of and DPS of a ship is the automatic control of the vessel heading and position. A more sophisticated definition is to maintain variations in vessel position and heading within acceptable limits, while achieving minimum thruster activity. This chapter considers the factors: Vessel motion - This is the dynamics of a free floating vessel in an offshore marine environment; Control system - This is a review of the control loop of force and moments: sensing: counteraction to force. The forces and moments are environmental plus task related i.e. pipe tension; Operational modes - Each vessel is supplied with several different modes of operation. The difference between the modes is the level of control available and how the position, heading speed and set points are generated. The combination of modes provided for a vessel depends upon its role. Thus, a cable laying vessel will need Auto Track mode, which will not be required for a drilling platform...