Research On Robust Control Applied To Ship And Submarine Maneuvering

Robust control theory applications to vessel and submarine steering are investigated systematically in this dissertation. It contains four parts which are design for wave filter, course control in waves, control system design for rudder roll stabilization and submarine space motioning control.Firstly , a new design methodology for wave filter based on extended states observer is presented in this dissertation. The 1st order wave disturbances is always inside the bandwidth of the servo and actuators of the vessel, so if the rudder or thruster actuator of the ship compensate for the oscillatory high frequency wave induced motion, It will cause too much control. However this can be avoiding by using wave filter which can separating the low frequency motion of the vessel with high frequency 1st order wave induced motion.In the part of vessel's course control, a simple and reasonable computing methods for the first and second order forces induced on a ship is discussed firstly, then a robust autopilot has been designed by active disturbances rejection control using course nonlinear equation directly. At the same time, a variable structure robust autopilot designed based on 1st order K-T equation. Simulation results under different sea condition shows: two kind of autopilot both have good robustness to system parameter perturbation and environment disturbance and the wave filter works well at large ranges, so frequently steering is avoided.In the part of rudder roll stabilization control system, a four freedom motion model including roll is built firstly. Based on it, the feature of disturbance and response of rudder roll stabilization system is analyzed deeply. It implies that the response amplitude of roll is depended on relative position between the encounter frequency and the open loop characteristic of ship's roll motion. When a ship moving beside beam sea, the phenomena is observed that the side direction hydrodynamic induced ship's roll motion will occur at a widely frequency range. Based on these, two kind of rudder roll stabilization control system is designed. Results show that the two control algorithms can both yield good control effect, at the same time, course keeps well.In the part of submarine space motioning control, decoupling control theory is applied to analysis the coupling character between depth and pitch with stern rudder and bow rudder in the vertical plane, and some useful results are acquired. Steering autopilot in lateral plane and pitch control in vertical plane are both designed with variable structure control. Depth control in vertical plane is designed by active disturbances rejection controller including tracking-differentiator. It need not to specific the switch depth when submarine maneuverability largely.