Speed Controller Design Utilizing H-Infinity Optimization and a Modal Drive Train Model for Torsional Oscillation Damping

$\mathcal{H}_{\infty}$ theory can be regarded as a promising approach for the performance optimization in mechatronic drive systems with flexible loads with respect to multiple objectives such as robust stability, precise reference tracking and minimization of mechanical strain due to oscillation damping. Modal decomposition is a fundamental instrument in the analysis and control of mechanical structures. In this paper, model transformation using modal decomposition of the mechanical drive train's torsional dynamics is considered as a concept providing enhanced capabilities in the formulation of the cost-function for a speed-controlled drive application. Promising results are achieved especially for drive trains featuring a second control-relevant mechanical natural mode.