Design and study of robust sliding-mode observers for dynamical system with unknown inputs distribute

The states estimation of dynamic system plays an essential role in the fields of science research and engineering application. The designing method of robust sliding mode observers with unknown disturbance is proposed in this paper, and the novel robust sliding mode observers and the optimal sliding strategies are designed by using the simplified technique based on the singular value decomposition technology to guarantee robustness to the uncertainties and external disturbances. The Lyapunov function is used as the critical condition of the stable observers which ensures the consistent convergence of the designed observers and the anticipative results of states estimation. The simulation results of the VTOL helicopter model illustrate the effectiveness of the proposed algorithms, and the characteristics of good track and the robustness to the unknown input disturbances in the designed sliding observers are proved by compared with ones of Luenberger observers.