中文说明：
给出了一个针对非线性不确定未建模系统的观测器实例。采用了鲁棒滑模观测器算法。原始论文原理在程序注释部分。
English Description：
An observer example for nonlinear uncertain unmodeled systems is given. The robust sliding mode observer algorithm is adopted. The principle of the original paper is in the program notes