Model Based Position Control of Nanopositioning- and Nanomeasuring Machines Using an Adaptive Friction Cancellation Approach

This work presents a model-based position control with a resolution in the nanometer range. The friction, which is the dominant disturbance on nanometer scale, is modeled with a physically motivated friction model. The model is identified off line, based on experimental data and is utilized as a feedforward controller. In the online mode the linear model parameters are adjusted by a recursive regression algorithm. Doing this, the feedforward controller is able to compensate the position-dependent friction. It is shown, that compared to a classical feedback controller the model-based approach is able to improve the dynamic of the controlled system and reduces the control deviation significantly.