Disturbance Rejection in Periodic Motion with Enhanced Constant Velocity Transitions via Adaptive Augmentation

This paper presents the practical implementation of an adaptive control strategy for a motion system subject to disturbances primarily caused by the fundamental frequency of the periodic reference signal. To this end, we devise a model for the motion platform which adequately describes the rigid-body dynamics. This physical model has been validated using measured data in the frequency domain to illustrate that it adequately captures the real dynamics of the motion platform. Using this model, we derive a standard motion control architecture with an adaptive augmentation. The control strategy consists of a feedforward controller based on model inversion and a baseline feedback controller for regulation plus an adaptive component resorting to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathcal{L}_{1}$</tex> control theory. The adaptive term is responsible for the rapid rejection of harmonic disturbances while recovering the nominal performance even in the presence of parametric perturbations. The effectiveness of the proposed control strategy is verified through real-time experiments featuring outstanding fast adaptation and rapid disturbance rejection.