Special issue featuring selected papers from the International Workshop on Bio-Inspired Robots (Nantes, France, 6–8 April 2011)

We are very pleased and honoured to present this special issue of Bioinspiration & Biomimetics that gathers a set of nine peer-reviewed articles whose results were in large part presented at the International Workshop on Bio-Inspired Robots which was held in Nantes, France, from 6–8 April 2011. The participants in this event have enthusiastic memories of the workshop, which was organized within the framework of EU-funded Future Emerging Technologies (ICT/FET) projects named Angels and Lampetra and hosted by the Ecole des Mines de Nantes and the IRCCyN Lab, Nantes, France. Following the workshop in Nantes, the general topic of this special issue is therefore on bio-inspired robots. The core theme of the special issue reflects a growing interest in developing bio-inspired autonomous robots that can interact with an unknown environment. This innovative scientific approach is first based on biological observations of animals from the point of view of locomotion, perception and their sensory-motor integration. Aquatic, aerial or terrestrial locomotion modes are of paramount importance for their high capabilities in terms of maneuverability/agility and energy efficiency. In the present special issue, [1] presents a swimming fully autonomous robot inspired by the species Lampetra fluviatilis which shows high maneuverability and efficiency, replicating the one of its natural counterpart. Such high performance swimming derives from the recovery of the energy that underwater moving vehicles usually leave in their wake. The Lampetra robot is actuated by an innovative technological solution that exploits the compliancy of a passive backbone to enhance swimming energetic efficiency. With [2] and [3], we shift from swimming to flying, by taking inspiration from insects. Insects, like hummingbirds, are capable of extremely rapid and precise aerial maneuvers. A rapidly growing community of researchers is gathering around the understanding of flapping-wing flight, and its mechanical imitation. At the boundaries of fluid mechanics, structural mechanics and robotics, these new kinds of aerial robots are envisaged to fly in inhabited areas. In this context, a challenging problem concerns the role and exploitation of the wing flexibility for maneuverability, control and actuation efficiency. The focus of [2] is on the effects of the structural flexibility of wings in the flapping flight of a butterfly. In [3], the authors show how flapping aerodynamics can lead to a most-advanced complete autonomous system: the Delfly robot from Delft University. At large, the use of flexible flapping wings is an example of a new emerging topic named `soft robotics' since it aims at solving robotics problems by exploiting the characteristics of soft organs. One of the challenging tasks of soft robotics is to design new actuators capable of reproducing the performance of living animals in terms of integration, rheology, efficiency and control. This perspective is at the foundation of a new generation of robots in our current life, i.e. capable of interacting with humans in a safe manner. The aim of [4]–[6] is to design such a new generation of soft actuators. Mainly taking inspiration from the hydrostats, they report on current works performed in the framework of the EU funded project Octopus, which aims at designing and building an underwater robot inspired by this animal. Beyond their specific scopes, these three articles are emblematic of the bio-inspired methodology, by going from Nature to robotics via mathematical modeling. Sensing is also of interest because inspiration from nature offers new sensory modalities and working principles. The extraordinary performance of supposedly simple animals is a source of wonder and new ideas for researchers. For example, with only a few hundred neurons, a fly is capable of aerial acrobatics beyond what the most sophisticated flying machine can achieve. By exploiting this idea, which consists of extracting simple concepts from neuroethology studies, [7] opens new perspectives in vision, based on the human ability to quickly select intrinsically salient targets in a visual scene: an ability which is fundamental for swift decision-making processes in unpredictable and unknown circumstances. Sensory–motor integration of animals, even the simplest ones, also presents many interesting sources of knowledge for control engineering. The nervous system integrates the information necessary to link perception to action. The active collaboration between roboticists and neurobiologists has already lead to transposition of the functional role of the lamprey's spinal cord into command algorithms for swimming robots (see again [1]). Two other cases of such fruitful collaborations are illustrated in [8] and [9]. These last two papers give a complementary point of view to the bio-inspired approach when applied to higher levels of autonomy. In particular one of the crucial problems of the collaboration between roboticists and neurobiologists is that brains and computers do not use the same principle to encode information. In this regard, [8] presents an interface which encodes sensory data from a humanoid robot into spikes and decodes spikes into motor commands that are sent to the robot. Finally, this issue ends with a biologically inspired navigation system for the mobile rat-like robot named Psikharpax, allowing self-localization and autonomous navigation in an initially unknown environment [9]. This last article represents the highest level (from body to cognition) of bio-inspiration and also completes the picture initiated with the Lampetra robot depicted in the first article. Finally, we are confident that this issue can represent a nice set of new ideas and research references and we really hope that readers enjoy the result of this effort. References [1] Stefanini C, Orofino S, Manfredi L, Mintchev S, Marrazza S, Assaf T, Capantini L, Sinibaldi E, Grillner S, Wallén P and Dario P 2012 A novel autonomous, bioinspired swimming robot developed by neuroscientists and bioengineers Bioinspir. Biomim. 7 025001 [2] Senda K, Obara T, Kitamura M and Yokoyama N 2012 Effects of structural flexibility of wings in flapping flight of butterfly Bioinspir. Biomim. 7 025002 [3] de Croon G C H E, Groen M A, De Wagter C, Remes B, Ruijsink R and van Oudheusden B W 2012 Design, aerodynamics and autonomy of the DelFly Bioinspir. Biomim. 7 025003 [4] Margheri L, Laschi C and Mazzolai B 2012 Soft robotic arm inspired by the octopus: I. From biological functions to artificial requirements Bioinspir. Biomim. 7 025004 [5] Mazzolai B, Margheri L, Cianchetti M, Dario P and Laschi C 2012 Soft robotic arm inspired by the octopus. II. From artificial requirements to innovative technological solutions Bioinspir. Biomim. 7 025005 [6] Renda F, Cianchetti M, Giorelli M, Arienti A and Laschi C 2012 A 3D Steady-state model of a tendon-driven continuum soft manipulator inspired by the octopus arm Bioinspir. Biomim. 7 025006 [7] Schiavone G, Izzo F, Simoes L F and de Croon G C H E 2012 Autonomous spacecraft landing through human pre-attentive vision Bioinspir. Biomim. 7 025007 [8] Gamez D, Fidjeland A K and Lazdins E 2012 iSpike: A spiking neural interface for the iCub robot Bioinspir. Biomim. 7 025008 [9] Caluwaerts K, Staffa M, N'Guyen S, Grand C, Dolle L, Favre-Felix A, Girard B and Khamassi M 2012 A biologically inspired meta-control navigation system for the Psikharpax rat robot Bioinspir. Biomim. 7 025009