Atomic force microscopes (AFMs) are used to measure surface topology of micro- or nanometer-sized samples.
In collaboration with the Nanotechnology Group of the ETH Zürich we participate in the development of new strategies for automatic scan control of AFMs. In particular, we focus on two main points. First, modeling and identification of control-relevant dynamical descriptions is a key-step towards performance improvement. Second, the design of control structures for scanning time reduction and for accuracy improvement provides considerable enhancement over existing commercial product specifications.

Magnetic bearings or bearingless slice motors are used in a wide variety of applications like low-friction drive systems or left ventricular assist devices (LVAD). The rotor position of magnetic bearings or bearingless slice motors is usually subject to several harmonic disturbances with time-varying frequencies. To achieve low power consumption and good vibration suppression, efficient control algorithms have to be invoked. We propose a time-varying disturbance rejection approach, which does not need to know the disturbance amplitude and phase, and changes its behavior according to the measured disturbance frequency.