Discrete-time port-Hamiltonian systems: A definition based on symplectic integration

Paul Kotyczka (1) , Laurent Lefevre (2)

1 TUM - Technische Universität Munchen - Technical University Munich - Université Technique de Munich
2 LCIS - Laboratoire de Conception et d'Intégration des Systèmes

We introduce a new definition of discrete-time port-Hamiltonian systems (PHS), which results from structure-preserving discretization of explicit PHS in time. We discretize the underlying continuous-time Dirac structure with the collocation method and add discrete-time dynamics by the use of symplectic numerical integration schemes. The conservation of a discrete-time energy balance-expressed in terms of the discrete-time Dirac structure-extends the notion of symplecticity of geometric integration schemes to open systems. We discuss the energy approximation errors in the context of the presented definition and show that their order is consistent with the order of the numerical integration scheme. Implicit Gauss-Legendre methods and Lobatto IIIA/IIIB pairs for partitioned systems are examples for integration schemes that are covered by our definition. The statements on the numerical energy errors are illustrated by elementary numerical experiments.

Mots clés: Port-Hamiltonian systems; Dirac structures; discrete-time systems; geometric numerical integration; symplectic methods

Domaines: Automatique / Robotique

Paul Kotyczka, Laurent Lefevre. Discrete-time port-Hamiltonian systems: A definition based on symplectic integration. Systems and Control Letters, 2019, ⟨10.1016/j.sysconle.2019.104530⟩. ⟨hal-02319637⟩