Coupled dynamics of piezo-tube and microcantilever in scanning probe devices and sensitive samples imaging

This Letter discusses the controlled positioning problem for scanning probe devices, especially the dynamic mode atomic force microscope. The necessity of real-time imaging in the nanoworld and the high sensitivity of nanoobjects make simulation-based works highly important. Here, a sufficiently accurate dynamic model has been provided and coupled with a dual control plan to lower the force of tip on the sample and consequently keep the sample from being damaged. First, the dynamic model has been validated using the available theoretical and experimental results, and the effectiveness of the suggested dual control plan has been demonstrated. Then, the effects of amplitude set point and piezo-tube and cantilever lengths have been studied, so that a lower tip-sample force and, simultaneously, a better image quality can be achieved. The obtained results show that the amplitude set point can be raised considerably to obtain a lower tip-sample force. Furthermore, the tip-sample force may be reduced by increasing the cantilever length, whereas the changing of the tube length has no effect. Although the presented results may be utilised to avoid some expensive tests before the nanorobotic operations, it is well suited to situations in which a soft or sensitive sample is scanned.