Event-driven feedback tracking and control of tapping-mode atomic force microscopy
Event-driven feedback tracking and control of tapping-mode atomic force microscopy
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敲击模式原子力显微镜的事件驱动反馈跟踪和控制
DOI：
10.1098/rspa.2007.0016
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
M. Paul
中科院分区：
文献类型：
--
作者：
Sambit Misra;H. Dankowicz;M. Paul
本文提出了一种事件驱动的离散实时反馈策略，用于跟踪和稳定原子力显微镜（AFM）悬臂梁在抽头模式下探针-尖端动力学中自然发生的周期振荡。具体来说，基于对动态生成的参考轨迹的系统动力学的估计线性化，通过施加悬臂支架与样品表面之间的垂直偏移量的离散变化来实现鲁棒的动态跟踪和稳定。在这里，不仅使用振荡幅度，作为典型的afm商业控制实现，而且还使用瞬时相位信息。结果表明，即使存在不确定性和有限的状态访问，在表面扫描过程中也可以实现稳定和理想的性能。特别是，该方法能够鲁棒跟踪和使用在缺乏控制时不稳定的低接触速度周期系统响应。
This paper presents an event-driven, discrete-in-time feedback strategy for tracking and stabilizing naturally occurring periodic oscillations in the probe-tip dynamics of atomic force microscope (AFM) cantilevers in tapping-mode operation. Specifically, robust dynamic tracking and stabilization is achieved by the imposition of discrete changes in the vertical offset between the cantilever support and the sample surface based on an estimated linearization of the system dynamics about a dynamically generated reference trajectory. Here, use is made not only of the oscillation amplitude, as is typical in commercial control implementations for AFMs, but also of the instantaneous phase information. It is shown that stabilization and desirable performance during surface scanning is possible, even in the presence of uncertainty and limited state access. In particular, the methodology enables robust tracking and use of low-contact-velocity periodic system responses that are unstable in the absence of control.