Electroactive Smart Materials: New Challenges for Control

In this paper, the main objective is to provide an overview of a new class of research problems for the area which is broadly termed smart structures control. To this end, we describe electroactive smart materials and focus on control issues which naturally arise. Such materials, typically nano and micro-polymers, have mechanical properties controlled by an electric field. Unlike existing approaches to control such as those based on piezoelectric actuation, the electroactive materials described here do not require electromechanical apparatus for actuation; i.e., they are self-actuating. Within this setting, in addition to basic modelling issues, a paradigm control problem is also formulated: the so-called sustained oscillation problem for an electroactive mass-spring-damper system. For a given electric field E, this formulation leads to a simple nonlinearity involving the product of the modulus of elasticity κ(E) and the displacement y. Subsequently, we obtain a bilinear state equation ẋ = A(u)x whose control, we conjecture, is highly non-trivial. Within this context, we consider the use of feedback to vary the electric field so as to assure that the desired oscillation is guaranteed with the least possible actuation effort. Copyright c ©2005 IFAC