Life extending robust control of a wind excited antenna

The paper deals with the problem of fatigue mitigation of wind excited stayed antennas using robust active control. The controller is required either to robustly stabilize the structure or to guarantee a satisfactory fatigue reduction for a realistic class of modeling uncertainty. The effects caused by material aging and failures as long as modeling inaccuracies are considered as model uncertainties in the context of a robust μ controller synthesis. A frequency and a time domain analysis have been carried out to address some basic issues. In details, the analysis of the effect of the model uncertainty on the achievable robust performance, the selection of the best position for the sensors, and the controller order reduction have been discussed. A realization of a spatially correlated wind load has been generated and used to compute the stochastic response of the full-order model of a stayed tall antenna. The fatigue in some nodes of the structure has been evaluated by applying the Miner rule and the “rain-flow” counting method. Simulations show the effectiveness of the proposed reduced order μ controllers for the mitigation of fatigue in presence of uncertainties.