The industrial sector often employs piezoelectric materials as actuators for a variety of uses, some of which requires a precise positioning while being limited by space and cost factors that impede the insertion of external position and force sensors. Piezoelectric Actuators are characterized by strong nonlinearities (hysteresis and creep), badly damped oscillations and sensitivity to the environment, especially temperature variation, that make the measurement of the position mandatory to guarantee the required precision and repeatability of piezoelectric-based positioning systems operating at the micro and nanoscale. Self-Sensing Actuation techniques allow the implementation of precise positioning control of Piezoelectric Actuators without the hindrance of external position sensors. This paper reviews the different Self-Sensing Actuation techniques used for precise positioning control of Piezoelectric Actuators. The principle of Self-Sensing Actuation is defined by the capability of deriving the physical state of a Piezoelectric Actuator (displacement, perceived force,...) 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 Piezoelectric Actuator itself (throughout current, voltage drop,...). The applicability and constraints of each Self-Sensing Actuation approach are examined in order to help in the determination of the most adequate approach for precise control of Piezoelectric Actuators positioning and handling force control.

This paper presents a displacement self-sensing method for piezoelectric actuators that takes into account the effect of the deformation of these latter on their electrical impedance. A self-updating digital electrical impedance equivalent to that of the piezoelement is suggested in order to overcome the mismatch problem met when considering a static analog electrical impedance as classically used. Then, the design of an observer that performs a thorough separation of the electric current due to the direct piezoelectric effect from the measured electric current is proposed in order to estimate the piezoelectric actuator displacement. The experimental results validate the proposed approach and demonstrate the efficiency of the developed self-sensing circuit and its observer to estimate the displacement of the piezoceramics actuator for long duration measurement of constant step signal.

Charge-based Self-Sensing Actuation (SSA) is a cost and space-saving method for accurate piezoelectric based-actuator positioning. However, the performance of its implementation resides in the choice of its geometry and the properties of the constituent materials. This paper intends to analyze the charge-based SSA’s performances dependence on the aforementioned parameters and properties for a piezoelectric cantilever. A model is established for this type of Piezoelectric Actuator (PEA), and a multi-objective function is defined. The multi-objective function consists of the weighted actuator and sensor objective functions of the PEA. The analytical optimization approach introduced herein aims to assess the evolution of the defined multi-objective function across a defined set of geometrical parameters and material properties and highlights the existence of a subset of solutions for an optimal charge-based SSA’s implementation. The commercially-available finite element analysis software, COMSOL Multiphysics, is used on the parametric model of the given structure to validate the analytical model. Then, experiments are conducted to corroborate the numerical and analytical modeling and analysis.