Digital Charge Estimation for Piezoelectric Actuators, an Artificial Intelligence Approach

For many piezoelectric actuators and their areas of operating, charge is proportional to the position of the actuator. Thus, for such actuators, estimation of charge is largely considered as an equivalent to position estimation. That is, a charge estimator may replace a costly and troublesome position sensor. Nevertheless, a significant portion of the excitation voltage is wasted for charge estimation. This squandered voltage, not used to deform the actuator, is called voltage drop. A class of charge estimators of piezoelectric actuators have a resistor in series with the actuator and can only work together with a digital processor. These are called digital charge estimators and have been shown to witness the smallest voltage drop compared to other charge estimators. This chapter first proposes a design guide for digital charge estimators of piezoelectric actuators to maximise the accuracy with the smallest possible voltage drop. The chapter then details the use of five different artificial intelligence (AI) techniques to tackle this design problem and assess their effectiveness through even-handed comparison.