SOS Based Robust Control for Dynamic Positioning System Subject to Actuator Saturation

In this paper, the problem of thruster saturation is considered for dynamic positioning systems of offshore platforms, specifically, a state feedback controller is developed for polynomial systems subject to actuator saturation. The sufficient conditions of stabilization problem are formulated in the form of sum of squares to ensure the desired H infinity performance, which can be numerically solved via the SOSTOOLS.For the modeling uncertainty problem caused by the uncertain hydrodynamic parameter, the results are extended to the uncertain system for the consideration of wider applications. Finally, simulations are conducted for a system with parameter uncertainties and thrust saturation in dynamic positioning system to illustrate the effectiveness and advantages of the proposed control strategy.