A real time robust observer for an Agonist-Antagonist Variable Stiffness Actuator

Tomas Menard (1) , Giorgio Grioli (2, 3) , Antonio Bicchi (2, 4)

1 Equipe Automatique - Laboratoire GREYC - UMR6072
2 Centro di Ricerca Enrico Piaggio
3 IIT - Italian Institute of Technology = Istituto Italiano di Tecnologia
4 IIT - Istituto Italiano di Tecnologia

We consider the problem of estimating the time- varying stiffness in real-time of a Variable Stiffness Actuator in an agonistic-antagonistic configuration. The estimation of the stiffness is done in two steps. First, we use operational calculus which provides a relation between the positions/velocities of the motors and the link, the torques of the motors and the stiffness. Second, we combine the obtained relation with a polynomial approximation of the stiffness and a recursive least square algorithm to fit the data. Simulations and experimental results are provided and demonstrate the effectiveness of the proposed approach.

Domaines: Automatique / Robotique

Tomas Menard, Giorgio Grioli, Antonio Bicchi. A real time robust observer for an Agonist-Antagonist Variable Stiffness Actuator. IEEE International Conference on Robotics and Automation, May 2013, Karlsruhe, Germany. ⟨hal-00787925⟩