Network modelling of physical systems: a geometric approach

It is discussed how network modeling of lumped-parameter physical systems naturally leads to a geometrically defined class of systems, called port-controlled Hamiltonian systems (with dissipation). The structural properties of these systems are investigated, in particular the existence of Casimir functions and their implications for stability. It is shown how the power-conserving interconnection with a controller system which is also a port-controlled Hamiltonian system defines a closed-loop port-controlled Hamiltonian system; and how this may be used for control by shaping tile internal energy. Finally, extensions to implicit system descriptions (constraints, no a priori input-output structure) are discussed.