An Overview of Piezoelectric Self-Sensing Actuation for Nanopositioning Applications: Electrical Circuits, Displacement, and Force Estimation

The industrial sector often employs piezoelectric materials as actuators for a variety of uses, some of which require a precise positioning while being limited by space and cost factors that impede the insertion of external position and force sensors. Piezoelectric actuators (PEAs) are characterized by strong nonlinearities (hysteresis and creep), badly damped oscillations, and sensitivity to the environment, especially temperature variation, which makes the measurement of the position mandatory to guarantee the required precision and repeatability of piezoelectric-based positioning systems operating at the microscale and nanoscale. Self-sensing actuation (SSA) techniques allow the implementation of precise positioning control of PEAs without the hindrance of external position sensors. This article reviews the different SSA techniques used for precise positioning control of PEAs. The principle of SSA is defined by the capability of deriving the physical state of a PEA (displacement, perceived force, and so on) without the use of external sensors to directly measure thereof, but rather by estimating it from the measurement of less intrusive and cheaper physical signals produced by the PEA itself (throughout current, voltage drop, and so on). The applicability and constraints of each SSA approach are examined in order to help in the determination of the most adequate approach for precise control of PEAs positioning and handling force control.