Actuators employing ferroelectric or ferromagnetic compounds are solid-state, efficient, and compact making
them well-suited for aerospace, aeronautic, industrial and military applications. However, they also exhibit
frequency, stress and thermally-dependent hysteresis and constitutive nonlinearities which must be incorporated
in models for accurate device characterization and control design. A critical step in the use of these
models is the estimation or re-estimation of parameters in a manner that is both efficient and robust. In
this presentation, we discuss techniques to estimate densities in the homogenized energy model based on
Galerkin expansions using physically motivated basis functions. The yields highly tractable optimization
algorithms in which initial parameter estimates can be obtained from measured properties of the data. The
efficiency and accuracy of the models and estimation algorithms are validated with experimental data.
A fundamental step in the model construction for ferroelectric, ferromagnetic, and ferroelastic materials is
the estimation or identification of material parameters given measurements of the material response. Moreover,
actuator and/or material properties may be a function of operating conditions which can necessitate the re-estimation of parameters if conditions change significantly. In this paper, we focus on the development of highly robust and efficient identification algorithms for use in industrial, aeronautic and aerospace applications.
Following a discussion of present and future applications, we summarize the homogenized energy model used to characterize hysteresis and constitutive nonlinearities in these compounds. We next discuss the parameter estimation problem and detail algorithms used to speed implementation. The validity of the framework is illustrated through comparison with experimental data.
In this paper we develop a mathematical model to simulate the actuation of a multilayer metallic strip. In the first step of the model development, we employ previous theory to quantify the radius of curvature in the unimorph due to differing thermal coefficients in the constituent materials. The resulting radius of curvature is subsequently used to compute the voltage required to uncurl the actuator. Numerical experiments were performed with the model and the trends were found to be in agreement with experimental data.