Regularization of Port-Hamiltonian Descriptor Systems

We study the regularization problem for port-Hamiltonian descriptor systems by proportional and/or derivative output feedback. Necessary and sufficient conditions are given, which guarantee that there exist output feedbacks such that the closed-loop system is regular, has index at most one, and is still port-Hamiltonian with desired rank properties. All results are derived based on condensed forms, computations of these condensed form can be implemented using only orthogonal transformations and hence are numerically reliable.