Enhanced Disturbance Observer-Based Precision Control for Piezoelectric Micro-Displacement Scanning Stage With Multiple Disturbances

The multiple disturbances of piezoelectric micro-displacement scanning stage (MDSS) (e.g., hysteresis nonlinearity, measurement disturbance, and parameter uncertainties) exist in combination. Aiming at disturbances that mainly affect motion accuracy and coupling property of disturbances, this article proposes a new composite antidisturbance controller combining enhanced disturbance observer (EDO). The EDO considers the inherent hysteresis and dynamic information of sensing measurement disturbance under the premise of considering the model parameter uncertainties, and overcoming the problem of rough estimation caused by regarding all disturbances as a lumped disturbance in classical disturbance observer. Parameters of the hysteresis model in EDO are determined using Hooke-Jeeves optimization algorithm. The proposed EDO could effectively estimate the hysteresis of piezoelectric MDSS and sensing measurement disturbance while not increasing the difficulty of parameter tuning and simplifying the modeling process. The stability of designed composite antidisturbance controller with EDO is proved. Moreover, through numerical simulations and experimental tests, as well as comparisons with control results of other classical control methods, the effectiveness of designed composite controller combined EDO is verified.