Abstract
An ultra-precise micro/nanopositioning system is one of the key requirements for the rapid advancements in the field of micro/nanotechnology. A frequently used used actuator in micro/nanopositioning systems is the piezoelectric actuator, which, although precise, exhibits some unwanted phenomena like hysteresis, creep and high-frequency vibrations. Hysteresis is recognized as the main nonlinearity in the piezoelectric actuator, which severely limits system performance or even leads to instability. Hysteresis compensation is usually performed with an inverse hysteresis model, which is often a challenging task. Motivated by the above challenges, this paper aims to analyze the tracking performance of a piezoelectric actuator with an intelligent fuzzy feedback controller cascaded in series with the Bouc-Wen feedforward compensator. The feedforward compensator is now designed without finding an inverse hysteresis model to avoid the inverse modeling complexity. The mathematical model of the considered system is identified from the real-time experimental data. The model parameters are estimated using the Output Error with Filtered Observations (OEFO) adaptation algorithm. The parameters of the considered Bouc-Wen hysteresis model are identified by using the nonlinear curve fitting problem. The achieved results with the suggested control scheme are then compared with a classical PID feedback controller cascaded in series with the feedforward compensator. The achieved results with the suggested fuzzy feedback controller cascaded with the Bouc-Wen feedforward compensator show the performance improvement in terms of tracking precision and also in compensating the hysteresis nonlinearity compared to the classical PID feedback controller.