Scheduled controller design for systems with two switching sensor configurations: a frequency-domain approach

In this paper, we consider a hybrid system consisting of a motion stage that exhibits, from a control point-of-view, position-dependent dynamics as a result of varying sensor configurations. A scheduled controller design is proposed that is intuitive for control engineers as all individual filters can be obtained using classical frequency-domain loop-shaping techniques thereby connecting to the industrial motion control practice. Moreover, data-based graphical conditions are provided in the frequency-domain under which closed-loop stability can be verified irrespective of how the switching between the controllers occurs in time. The effectiveness of the proposed scheduling technique, as a way to improve both transient and steady-state performance compared to the current state-of-the-art industrial control solution, is demonstrated by means of experiments on a high-precision industrial motion stage.