Mechanical self-stabilization, a working hypothesis for the study of the evolution of body proportions in terrestrial mammals

Rémi Hackert (1, 2) , Nadja Schilling (3) , Martin S Fischer (3)

1 MAOAC - Mécanismes adaptatifs : des organismes aux communautés
2 AESO - Adaptations et évolution des systèmes ostéomusculaires
3 Institut fuer spezielle zoologie und evolutionsbiologie

Locomotion is a behaviour resulting from the interaction of the nervous and musculoskeletal systems and the environment. However, the musculoskeletal systems of some terrestrial mammals present an intrinsic ability to realize a dynamic stable locomo- tion. Current anthropomorphic passive walkers demonstrate that a pure mechanical system with legs and arms is able to walk down an inclined plane. Numerical simulations confirm that self-stabilization of the mechanics is acting in running too. The necessity to ensure the dynamic stability of a cyclic locomotion set physical constraints to the musculo-skeletal system. A description of the locomotor apparatus with neuromechanical variables like the stiffness – accessible to the experimentation – enables for maintain- ing the number of degrees of freedom of biomechanical models as low as possible. The maximization of the robustness of the mechanical self-stabilization of the models with regard to the body proportions represents for future simulations an optimization criterion that should bring a new light into the comprehension of the body proportions.

Mots clés: stability; locomotion; body proportion; running; quadruped; mammals

Domaines: Biologie animale; Biodiversité

Rémi Hackert, Nadja Schilling, Martin S Fischer. Mechanical self-stabilization, a working hypothesis for the study of the evolution of body proportions in terrestrial mammals. Comptes Rendus. Palevol, 2006, 5 (3-4), pp.541-549. ⟨10.1016/j.crpv.2005.10.010⟩. ⟨hal-00365982v1⟩