Multisensor Input for CPG-Based Sensory—Motor Coordination

Rodolphe Héliot (1, 2, 3) , Bernard Espiau (1)

1 BIPOP - Modelling, Simulation, Control and Optimization of Non-Smooth Dynamical Systems
2 DEMAR - Artificial movement and gait restoration
3 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

This paper describes a method for providing in real time a reliable synchronization signal for cyclical motions such as steady-state walking. The approach consists in estimating online a phase variable on the basis of several implicit central pattern generator associated with a set of sensors. These sensors can be of any kind, provided their output strongly reflects the timedmotion of a link. They can be, for example, spatial position or orientation sensors, or foot sole pressure sensors. The principle of the method is to use their outputs as inputs to nonlinear observers of modified Van der Pol oscillators that provide us with several independent estimations of the overall phase of the system. These estimations are then combined within a dynamical filter constituted of a Hopf oscillator. The resulting phase is a reliable indexing of the cyclic behavior of the system, which can finally be used as input to low-level controllers of a robot. Some results illustrate the efficiency of the approach, which can be used to control robots.

Mots clés: sensory-motor coordination; Central pattern generator (CPG); oscillator; sensors

Domaines: Automatique / Robotique

Rodolphe Héliot, Bernard Espiau. Multisensor Input for CPG-Based Sensory—Motor Coordination. IEEE Transactions on Robotics, 2008, 24 (1), pp.191-195. ⟨10.1109/TRO.2008.915433⟩. ⟨hal-00346645⟩