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Overall Objectives
Scientific Foundations
Application Domains
New Results
Contracts and Grants with Industry

Section: New Results

Acroban v2: improving morphological computation with dampers

Participant : Olivier Ly.

Furthermore, theoretical studies and experiments concerning in particular dynamics of passive walkers drove us to design and build a new version of Acroban. This new version has two goals both fitting in the study of the impact of morphology in the behaviour of the robot:

Indeed, this new version uses RX-28 motors which are lighter than the RX-64 motors used in the first version of Acroban. The robot is smaller and lighter. First experiments show that the obtained ratio weight/power is better than the first version. Movements of the robot, and in particular amplitude of locomotion movements, are not limited by torque now. Second, we have experimented plastic materials to design the structure in order to make it naturally flexible comparing to the metal used in the first version. This way, we improve the natural compliance of the robot. Finally, and this is probably the most important change, we used non actuated linear joints in the hip and in the spline. To control these linear joints, instead of servo-motors, we use dampers. This kind of design is new in humanoid robotic. While bringing new control problems (because of the non-controled joints which makes the robot semi-passive), this design softens schocks in a significant maner. Experiment shows that stability of the whole structure is greatly improved especially during locomotion.


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