First-Order Based Non-Linear Open-Loop Identification of a Ionic Polymer Bending Actuator and Derived Linear PI closed-loop Control

Bertrand Tondu (1) , Aiva Simaite (2) , Philippe Souères (1) , Christian Bergaud (2)

1 LAAS-GEPETTO - Équipe Mouvement des Systèmes Anthropomorphes
2 LAAS-MEMS - Équipe Microsystèmes électromécaniques

Tri-layer electroactive bending polymeric artificial muscles generally exhibit no overshoot during open-loop step response with a non-zero initial slope when the output is the vertical position of the bending sample tip. If a simple linear first order is not able to capture the variety of step responses when the u-voltage varies along its practical range, we propose to identify such a bending step contraction by a nonlinear system derived from a linear first order system in the form: u e k T t r) 1 (/   where the parameters k, T and r depend on the u-control voltage. We show the relevance of this approach for identifying the step-response of a PEDOT:PSS/PVDF/ionic liquid actuator developed at the laboratory. As a consequence, we show that a linear PI-controller is a simple and an efficient approach for a closed-loop control of the bending actuator. A simple method taking into account voltage saturation control is proposed and applied to both real steps and sine-wave tracking.

Mots clés: Artificial muscle; Bending electroactive polymer; Nonlinear identification

Domaines: Robotique [cs.RO]

Bertrand Tondu, Aiva Simaite, Philippe Souères, Christian Bergaud. First-Order Based Non-Linear Open-Loop Identification of a Ionic Polymer Bending Actuator and Derived Linear PI closed-loop Control. CIMTEC 2016, Jun 2016, Perugia, Italy. ⟨hal-02004975⟩