Dynamic positioning simulation, thrust optimization design and control of a drill ship under disturbances and faulty thruster

The dynamic positioning simulation of an actual drill ship under a normal and faulty condition is proposed using MATLAB (TM) and Simulink (TM) software. The proposed simulation model provides a means to control a non-linear and coupled OD21 drill ship under different external perturbations, such as wind, wave, current and thruster failure during the design stage. A proportional-integral-derivative (PID) controller for the dynamic positioning ship system was designed and validated with experimental results from a sea trial. Through simulation, the proposed PID control and thrust allocation method are able to maintain the desired heading angle under various test conditions, such as drilling, standby and thruster failure.