The nonlinearities of piezoelectric actuators and external disturbances of the piezoelectric nanopositioning stage impose great, undesirable influences on the positioning accuracy of nanopositioning stage systems. This paper considers nonlinearities and external disturbances as a lumped disturbance and designs a composite control strategy for the piezoelectric nanopositioning stage to realize ultra-high precision motion control. The proposed strategy contains a composite disturbance observer and a continuous terminal sliding mode controller. The composite disturbance observer can estimate both periodic and aperiodic disturbances so that the composite control strategy can deal with the disturbances with high accuracy. Meanwhile, the continuous terminal sliding mode control is employed to eliminate the chattering phenomenon and speed up the convergence rate. The simulation and experiment results show that the composite control strategy achieves accurate estimation of different forms of disturbances and excellent tracking performance.

中文翻译：

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压电纳米定位平台复合扰动观测器及连续终端滑模控制设计

压电执行器的非线性和压电纳米定位台的外部干扰对纳米定位台系统的定位精度产生了很大的不良影响。本文将非线性和外部扰动视为集中扰动，设计了压电纳米定位平台的复合控制策略，以实现超高精度运动控制。所提出的策略包含一个复合干扰观测器和一个连续终端滑模控制器。复合扰动观测器可以同时估计周期和非周期扰动，从而使复合控制策略能够高精度地处理扰动。同时，采用连续终端滑模控制，消除抖动现象，加快收敛速度​​。仿真和实验结果表明，该复合控制策略实现了对不同形式扰动的准确估计和良好的跟踪性能。