RALPHY: a dynamic study of a quadruped robot

We describe a control/command architecture developed for our quadruped robot RALPHY (French acronym for legged robot with pneumatic actuators). Dynamical and real time aspects as well as theoretical and practical approaches have been take into account. In order to hierarchize and distribute as far as possible the different tasks to be realized, the robot dynamic model has been decomposed in two parts. Hence, in the architecture organization chart, a “Leg level” commands the leg movements by means of leg Inverse Dynamic Model and a “Coordinator level” controls the leg movements as well as the platform stability. This stability is ensured by a “center of mass acceleration control” and a “force distribution control”