Search

This paper presents a nonlinear sliding mode control algorithm for the path following of the underactuated ships in presence of the uncertain parameters and unknown external disturbances. Firstly, the path following control is transformed into the heading control by the nonlinear sliding mode method, and the unknown lateral drift part is estimated by a nonlinear disturbance observer. Then, the heading control law is proposed by the nonlinear sliding mode and the radial basis function (RBF) neural networks, which could be employed to approximate the uncertain parameters or external disturbances. In the proposed algorithm, the ship could coverage to the desired path well and the unknown lateral drift part could be observed. Finally, the effectiveness and the robustness of the proposed algorithm have been verified through the numerical simulation.

Reasonable and practicable sequence of generating unit restoration can ensure the rapidness of restoration process. This paper presents a new definition of transmission line weight and a conception of operation success rate of generating unit restoration paths based on the presented weight definition and the self-excitation margin. An optimization model is proposed to maximize the restoration path operation success rate and the total power generation capability over a restoration period. The model is solved by Dijkstra algorithm and the modified particle swarm optimization(PSO) algorithm with crossover factors. Simulation results on IEEE 30-bus system and Shandong power grid of China demonstrate the fast optimization and the high feasibility of restoration plan.