A vibration suppression approach to high-speed atomic force microscopy

The possibility of many new applications and novel scientific observations can be provided by efficient and reliable high-speed atomic force microscopy techniques. However, the reliability of the AFM images decreases significantly as the imaging speed is increased to levels required for the targeted real-time observation of nano-scale phenomenon. One of the main reasons behind this limitation is the excitation of the AFM dynamics at high scan speeds. In this research we propose a piezo based, feedforward controlled, counter actuation mechanism to compensate for the excited out-of-plane scanner dynamics. For this purpose the AFM controller output is properly filtered via a linear compensator and then applied to a counter actuating piezo. The information required for compensator design is extracted from the cantilever deflection signal hence, eliminating the need for any additional sensors. The proposed approach is implemented and experimentally evaluated on the dynamic response of a custom made AFM. It is further assessed by comparing the imaging performance of the AFM with and without the application of the proposed technique and in comparison with the conventional counterbalancing methodology. The experimental results substantiate the effectiveness of the method in significantly improving the imaging performance of AFM at high scan speeds. © 2012 AACC American Automatic Control Council.