Acceleration Feedback in Dynamic Positioning

摘要: This dissertation contains new results on the design of dynamic positioning (DP) systems for marine surface vessels. A positioned ship is continuously exposed to environmental disturbances, and objective DP system maintain desired position heading by applying adequate propeller thrust. The disturbances can be categorized into three classes. First, there are stationary forces mainly due wind, ocean currents, static wave drift. Secondly, slowly-varying drift, a phenomenon experienced in irregular seas. Finally rapid, zero mean linear loads causing oscillatory motion with same frequency as incoming train. main contribution this method better compensation second type forces, introducing feedback from measured acceleration. It shown theoretically through model experiments that performance improved without compromising thruster usage. specific contributions are: • Observer design: Two observers filtering capabilities was developed, analyzed, tested experimentally. Both them incorporate and, if available, velocity acceleration measurements. Filtering out induced particularly important whenever used controller, because an signal, high dominate. Controller low speed tracking controller has been developed. proposed control law regarded extension any conventional PID-like design, stability guaranteed bounded yaw rate. numerically calculating upper bound proposed, most ships resulting will higher than physical limitation. For completeness, missing nonlinear term that, included would ensure global exponential identified. mapping action forces. allocation overactuated equipped propellers rudders derived. Active use rudders, together action, advantageous operation, overall fuel consumption reduced. ship, Cybership II, low-cost reference developed aim testing concepts. were carried at recently Marine Cybernetics Laboratory, while experiment Guidance, Navigation Control Laboratory. have published or still under review publication international journals conferences.