The birds neck, an arm for the robots – AVINECK

The aim of functional morphology is to investigate and understand the relationships between shape, function, and physiology of the musculo-skeletal system and its mechanical properties. The mechanical properties of natural systems selected and ‘optimised’ through natural selection can inspire engineering solutions, and in particular robotics applications. These approaches belong to the field of biomimetics, or bio-inspired design, a growing field at the interface of biology and engineering. The objective of the present project is to quantify and understand the the anatomy of the bird neck, its mechanical properties and function, and to implement this information into the design of robotic systems. Like humans, birds are strictly bipedal species. Their forelimbs changed into wings and are specialized for flying. Birds no longer have hands and the functions performed by the hands in other species, including humans, are thereby carried out by the beak. The neck thus becomes the functional equivalent of an arm. In fact, some bird species are specialized in such a way that the head-neck system acts as a tool-bearing arm. This is the case for instance of woodpeckers. When these birds tap the trees to excavate nest cavities their cranio-cervical system works as a jackhammer held by the arm: the neck both propels the beak like the jackhammer and softens the impact between the head and the trunk like an arm does. In this project, the functional-morphological adaptations of the cranio-cervical system in birds will be used to test macro-evolutionary hypotheses about its origins, and to propose how these original biological solutions can be a natural help to overcome technological challenges in robotics. A consortium of biologists from the Museum national d’Histoire naturelle (MNHN), specialists in functional morphology, biomechanics, morphometrics, ornithology, and behavior, and of roboticists of the Institut de Recherches en Communications et Cybernetique de Nantes (IRCCyN), specialized in production robotics, humanoid robotics, and bio-inspired robotics, has been created to fulfill these goals.
A study of the 3D morphology of the head-neck system in a large sample of birds will define the features and the boundaries of the avian neck morphospace. A morpho-functional study will subsequently focus on a subset of highly specialized species. We hypothesize that their specializations, added to a generalized functional repertoire, correspond to fine tuned mechanical properties which allow the birds to optimally perform while minimizing energy expenditure. The behavior of the selected species corresponds to technological challenges for robotic manipulators in terms of performance, such as dexterity and workspace: contrary to biological hydrostats such as the elephant´s trump or the cephalopod´s tentacles, bird necks use a rigid vertebral architecture; however, contrary to the snakes´ column, these serial structures do not lie on the ground, but perform in full 3D space. The architectural paradigm of tensegrity will be the motto of this project, as it makes an adequate bridge between biology and robotics. Tensegrity has proved very efficient to model human musculo-skeletal systems of living beings.

Using this approach, we aim to:
1) in biology, determine the role of the cranio-cervial system in the evolution of bird diversity, and to participate in the debate concerning the role of modularity in evolution.
2) in biomimetics, to describe the underlying mechanical principles which can be used for the design of innovative robotic manipulators with enhanced performances, and to test these principles by building prototypes.