Fast terminal sliding mode control for submarine course by adopting tracking-differentiator

The submarine course control system is of strong nonlinearity, time variation and strong coupling. Traditional linear control methods cannot achieve the desired performance, then a lot of nonlinear methods were used to control it. The fast terminal sliding mode control method was presented to control the submarine course in this work. Compared with the traditional sliding mode control, the fast terminal sliding mode control can achieve finite time convergence, smaller steady error, faster convergence rate and stronger robustness. The finite time convergence of the FTSM submarine course control method was proved using the Lyapunov theory. In order to obtain the differential signals, the tracking differentiator was used. The proposed control method was numerically studied and its effectiveness was verified.