Abstract
We propose a new control method of the micro cantilever probe in atomic force microscopy (AFM) for biologic imaging. The observation is concerned with operation in water or aqueous bufferin where the Q value of the cantilever is reduced. In this situation, it is very difficult to obtain the natural frequency of the micro cantilever probe. The utilization of self-excited oscillation is known as a method to overcome the difficulty. Furthermore, for the detection of the characteristics of soft biological material, the non-contact mode, that the probe does not contact to the material, is required for avoidance of local deformation and destruction of the material. In this study, for realizing the no contact mode of the self-excited micro cantilever probe, van der Pol type self-excited micro cantilever beam is designed by bifurcation control due to linear-plus-nonlinear feedback control.
