Modeling and Robust Deflection Control of Piezoelectric Microactuators Modelled by Zero-Order Numerator Interval System

Piezoelectric actuators have received an increasing attention these last years thanks to the high resolution of displacement, high force density and fast response time that can offer piezoelectric materials. However, piezoelectric actuators are highly sensitive to environmental disturbances and typify strong nonlinearities that undeniably reduce the expected positioning accuracy. H∞ or μ-synthesis techniques were often used to control these actuators. However, these techniques derive high-order controllers which are hard to implement and that therefore impede the development of real packaged microsystems. This paper aims to design low-order controller ensuring robust performances for piezoelectric actuators. In the approach, first we use a linear model with uncertain parameters that are bounded by interval numbers. Then, on the basis of the interval model and the required performances, a low order controller is computed using a direct synthesis method. The proposed method is suitable for a class of models: transfer functions with zero-order numerator. The experiments confirm the robustness of the proposed method.