Performing Explosive motion using a multi-joint arm actuated by pneumatic muscles with quasi-DDP optimal control

Ganesh Kumar Hari Shankar Lal Das (1, 2) , Bertrand Tondu (1, 2) , Florent Forget (1) , Jérôme Manhes (3) , Olivier Stasse (1) , Philippe Souères (1)

1 LAAS-GEPETTO - Équipe Mouvement des Systèmes Anthropomorphes
2 LESIA-INSA - Laboratoire d'Étude des Systèmes Informatiques et Automatiques
3 LAAS-I2C - Service Instrumentation Conception Caractérisation

With the rapid evolution of robotic technology, robots are expected to perform various complicated task. Explosive motions like throwing, kicking or jumping are some of the ambitious tasks interesting for researchers. In the present paper, we would like to present a ball throwing task performed by an anthropomorphic arm with each joint actuated by an agonist-antagonistic pair of Mckibben artificial muscles. Pneumatic actuators have inherent compliance and hence they are very interesting for applications involving interaction with environment or human. But controlling such kind of actuators is not trivial. The paper presents an implementation of iterative Linear Quadratic regulator (iLQR) based optimal control framework to control such actuators. The method is applied to positioning tasks and generation of explosive movements by throwing a ball to a maximum distance. It is then compared to traditional control strategies to justify that optimal control is effective in controlling the position in highly non-linear pneumatic systems. Also the importance of varying compliance is highlighted by repeating the tasks at different compliance level. The algorithm validation is reported here by several simulations and hardware experiments in which the shoulder and elbow flexion are controlled simultaneously.

Domaines: Automatique / Robotique

Ganesh Kumar Hari Shankar Lal Das, Bertrand Tondu, Florent Forget, Jérôme Manhes, Olivier Stasse, et al.. Performing Explosive motion using a multi-joint arm actuated by pneumatic muscles with quasi-DDP optimal control. MSC-2016 IEEE Multi-Conference on Systems and Control 2016, Sep 2016, Buenos Aires, Argentina. ⟨hal-01382328⟩