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Computational Foundations of Anthropomorphic Action

Final Report Summary - ACTANTHROPE (Computational Foundations of Anthropomorphic Action)

Human beings and humanoid robots share a common anthropomorphic shape. Whereas the ultimate goal of roboticists is to provide humanoid robots with autonomy, life scientists are striving to gain an understanding of the foundations of human action, in domains ranging from medicine and rehabilitation to ergonomics. Neuroscience and its quest to understand the computational foundation of the brain provides a further entry point to robotics. Despite their different scientific cultures and backgrounds, the communities of life scientists and roboticists are pursuing converging objectives.

A key to understanding anthropomorphic action that can bridge robotics and life sciences is gaining insight into the fundamental mechanisms of the human body. The objective of Actanthrope is to explore such mechanisms via three viewpoints on anthropomorphic action from robotics, neuroscience, and biomechanics perspectives respectively. The core idea grounding the research in Actanthrope is to promote mathematical methods which have the potential to bridge the various perspectives and to propose coherent models of the anthropomorphic action.

From a mathematical point of view, the human (or humanoid) body is both a redundant system and an underactuated one. It is redundant because its number of degrees of freedom is usually much greater than the dimension of the tasks to be performed. It is underactuated because there is no direct actuator allowing the body to move from one place to another place. To do so, the human must use its internal degrees of freedom and actuate all his limbs following a periodic process, namely bipedal locomotion. Actions take place in the physical place, while they originate in the sensory-motor space. Thus, geometry is the core abstraction linking three fundamental action spaces: the physical space where the action is expressed, the motor space, and the sensory space. The emergence of symbols can be understood by the geometric structure of the system configuration space. Such a structure depends on the role of the sensors in action generation and control. From such mathematical point of view, optimization appears as a general paradigm to select a motion that fulfils a given action.

To make the approach effective, the project has contributed to the development of several important mathematical software opensource libraries dedicated to motion planning and control for anthropomorphic systems. Based on these computational resources, innovative approaches to humanoid locomotion have been demonstrated on robot platforms HRP2 and Pyrène. Pyrène has been designed within Actanthrope and made in partnership with the company Pal-Robotics. All robot’s degrees of freedom are force controlled. This innovative design makes Pyrène the first prototype of a new generation of humanoid robots. It is now a platform development to study the industrial applications in aerospace industry within the framework of ROB4FAM, a joint Airbus-CNRS laboratory. Another highlight of the project is the introduction of the so-called Yoyo-Man model. This model allowed to better understand what are the motor synergies during walking and what role the head is playing in the control of the locomotor trajectories. Such results open a route design new mechanical and control schemes of humanoid robots.

Actanthrope developed a resolutely interdisciplinary research. The best illustration is given by the international workshops organized by the project from 2014 to 2017 and respectively devoted to “Dance Notion and Robot Motion” with choreographers and dancers, “Geometric and Numerical Foundations of Movements” with mathematicians, “Biomechanics and Robotics” with life science researchers and “Wording Robotics” with linguists and philosophers. All four workshops gave rise to the publication of a book published the STAR Series of Springer.

Finally, in the domain of contemporary art, Actanthrope has been the kingpin of the artwork transHumus presented at the 56th Venice Biennale and aiming at freeing trees from their roots. Robotics allowed to translate the poetic ambition of the artist into technological terms.