State and Disturbance Estimation for Robust Control of Fast Flexible Rack Feeders

Rack feeders as automated conveying systems for high bay rackings are of high practical importance. To shorten the transport times by using trajectories with increased kinematic values accompanying control measures for a reduction of the excited structural vibrations are necessary. In this contribution, the controloriented modeling for an experimental set-up of such a high bay rack feeder and the model-based design of a gain-scheduled feedforward and feedback control structure is presented. The rack feeder is modeled as an elastic multibody system. For the mathematical description of the bending deflections a Ritz ansatz is introduced for the first two bending modes. The tracking control design is performed separately for both axes using decentralized state space representations. Unmeasurable states as well as remaining uncertainties are estimated by a combined state and disturbance observer. Both the achievable performance and the resulting tracking accuracy of the proposed control concept are shown by measurement results from the experimental set-up.