研究不确定非线性系统的输出跟踪问题。针对系统中的未建模动态和广义的不确定性，基于李亚普诺夫稳定性理论提出了一种变结构控制方案，它不要求系统的不确定性满足匹配条件，仅要求已知不确定性的有界约束。从理论上证明了闭环跟踪系统全局渐近稳定，系统信号保持有界。仿真实例证实了理论结果。 Research on Output Tracking of Uncertain Nonlinear Systems. Aiming at the unmodeled dynamics and generalized uncertainties in the system, a variable structure control scheme is proposed based on Lyapunov stability theory. It does not require that the system’s uncertainties satisfy the matching conditions and only requires known uncertainties Bounded constraints. It is theoretically proved that the closed-loop tracking system is globally asymptotically stable and the system signal remains bounded. Simulation results confirm the theoretical results.