中文摘要：

在工业领域，机械传动系统、液压系统等往往含有间隙特性，这类系统可以用带间隙的三明治系统描述．本文针对带间隙的三明治系统特点，构建了一种非光滑观测器以对系统状态进行估计．首先根据带间隙三明治系统的特点，采用分离原理，建立了描述系统特性的非光滑状态空间方程．据此构造了能够随系统工作区间变化而自动切换的非光滑观测器，给出了相应的收敛定理及其证明．最后通过伺服液压系统的例子，分别比较了非光滑观测器和传统的观测器对状态的跟踪效果，比较结果表明非光滑观测器对于带间隙三明治系统状态变量估计的准确性要优于传统的观测器．

英文摘要：

Industrial systems involving backlash, such as mechanical transmission systems and hydraulic systems, can be described by socalled sandwich systems with backlash. A novel nonsmooth observer is proposed to handle the state estimation for sandwich systems with backlash. Based on the characteristics of the system, a nonsmooth statespace equation is constructed by using the separation principle. A nonsmooth observer is developed based on the obtained statespace equation. The observer switches automatically among different operating zones according to the changes of operation conditions. The convergence of the nonsmooth observer is discussed. The application of this observer to a practical hydraulic servo system is realized. The comparison of tracking performances of the hydraulic servo system is made between the proposed nonsmooth scheme and the conventional method. It is shown that the proposed nonsmooth approach is with much better estimated performance.