非线性不确定系统的鲁棒滑模观测器设计

Walcott-Zak观测器虽然对系统的非线性／不确定性具有鲁棒性，但观测器的设计需要满足严格的假设条件，设计参数的选取需要计算大量不等式。针对当系统维数较高时，Walcott-Zak观测器难以设计，在Walcott-Zak观测器基础上，提出了一种鲁棒滑模观测器，基于设计新的控制策略，避免了Walcott-Zak观测器所必须满足的严格条件，其设计条件没有Walcott-Zak观测器苛刻，设计参数的选取不需要求解大量方程，同时能保证对系统的非线性／不确定性具有鲁棒性。通过设计滑模，可以调整观测器跟踪系统状态的收敛速度，使状态估计达到预期的指标。仿真结果验证了控制策略的有效性。

Robust sliding mode observer design of nonlinear uncertain systems

The Walcott-Zak observer is robust to the nonlinearities and/or uncertainties of systems. But its design must satisfy strict conditions, and is associated with a lot of manipulation and solution of the inequalities. For the high-order systems, it is difficult to design. Based on Walcott-Zak observer, a robust sliding mode observer is presented, and a new control strategy in the observer is proposed in this paper to avoid the strict condition in design of the Walcott-Zak observer. The condition that should be satisfied for designing the observers in the paper is not so strict as that of the Walcott-Zak observer. The design of the observer's parameters need not solve a lot of equations. The observer proposed in the paper is robust to the nonlinearities and/or uncertainties of systems. The convergence rate between the observer and the system can be changed by choosing a suitable sliding mode manifold, so as to attain the desired performances. Simulation results are presented to validate the design.