DP3 Engineering Simulation System

DP3 Class Engineering Simulation System

Ships and offshore units in the ocean environment are affected by wind, wave and forces by propulsion system. Position, heading and velocity of units are changed from moment to moment by loads. In order to meet the designed positioning capability, DP controller inputs are forces in surge, sway and moment in yaw.

Features of Simulation System


Thruster Allocation

DP system’s controller continuously calculates the actual force requirements in the alongships and athwartships directions (the force setpoint), and the required rotational moment (the turning moment setpoint). The Thruster Allocation distributes these setpoints as pitch/rpm/force/load and azimuth control signals to each thruster/propeller, thus obtaining the force and moment required for the position and heading control.

DP Capability analysis

DP capability defines a DP vessel’s station-keeping ability under given environmental and operational conditions.
Exactly balanced by the maximum available thrust offered by the thruster configuration.
Presented by means of a thrust utilization envelope instead of a limiting wind speed envelope
Means of a limiting mean wind speed for a discrete number of wind angles of attack

Consequence Analysis

Consequence analysis verifies that the vessel will remain in position even if the worst case failure occurs.
Verify the thrusters remaining in operation
Lead to a loss of position due to insufficient thrust for the prevailing environmental conditions
Simulates the thrust and power remaining after the worse case failure, based on manual input of weather trend

DP Operational Modes

Auto Heading Mode

In the Auto Heading mode, the system accurately controls the heading:
Present Heading, which maintains the vessel's current heading
Change Heading, which rotates the vessel to the specified heading applying specified rate of turn
Minimum Power Heading, which continuously optimizes the vessel's heading for the lowest power consumption

Auto Position mode

In the Auto Position mode, the system automatically controls the heading and position of the vessel
Present Position, which maintains the present vessel position
Change Position, which moves the vessel to a new position with requested speed and acceleration

Joystick mode

In the Joystick mode, the operator controls the vessel using the three-axis joystick. Joystick operation can be combined with automatic heading control or with partial position control to ease e.g. docking. It can also incorporate automatic wind compensation to allow increased operational focus on ship handling.

Follow Target Mode

Dynamic Positioning system can command the vessel to follow an ROV during e.g. pipe inspection using hydro acoustic measurements from mobile transponder mounted on the ROV.

Autopilot mode

Wheel-marked Autopilot can be integrated in the DP system. Speed can be controlled by propulsion levers or system joystick.

Application of Simulation System to Offshore Projects

Project : FEED Design Project

Installation of 1,000ton Module of Semi-submersible Platform
Main Usage
Basic Design of Bumper and Guide
Verification of Main Equipment Arrangement
Simulation Test of Dynamic Positioning

Project : Sleipnir Project

Operation and Maintenance of Offshore Crane
Main Usage
Development of Ballast, Crane, DP System
Study on Operational Technology
Simulation for Verification of Operation and Maintenance Process