This paper describes the analysis and control of a two degree-of-freedom (DOE) monolithic piezoelectric actuator. This actuator is part of a six-DOF manipulator 1 capable of linear resolution to 2 nm and angular resolution to 1 arc-second. Design of this actuator differs from the existing ones in that it has a monolithic structure which enables a high bandwidth, low drift, and high force realization. A number of nonlinearties exist in the actuator, stemming from the geometry and material properties. For example, coupling of the actuator elements can be modeled as a soft spring which increases' displacement/drive-voltage gain (scale factor) at high actuation levels. In this work, a combination of feedforward (amplitude-dependent command prefiltering/input shaping) and feed, back control are applied to reduce the effects of 1) scale factor nonlinearties; 2) hysteresis; and 3) output oscillations.
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