Proceedings of the 4th IFAC Workshop on Lagrangian and Hamiltonian Methods for Non Linear Control, 4, 30-35 University of Groningen Proceedings of the 4th IFAC Workshop on Lagrange and Hamiltonian Methods for Non Linear Control LHMNLC 2012 LHMNLC 2012, Aug 2012, Bertinoro, Italy. pp.30-35, ⟨10.3182/20120829-3-IT-4022.00042⟩