Modeling and control of a PZT precise positioning device with a damper

Abstract

The authors have researched and developed a highly precise positioning device that uses a piezoelectric element (PZT) and a lever mechanism, which is used to increase the displacement amplitude. Because this device uses elastic deformation of a hinge structure, the resonance peak is very high. Therefore, we attached a damper composed of visco-elastic material (VEM) and a restriction plate to reduce this phenomenon. However, at low range of the frequency response, the gain was reduced by several decibels. We clarified that this damper was the factor to cause an overshoot by identifying a high order model and performing detailed analysis in the previous paper. However, the precision was limited because we modelled a gain reduction area in the first-order phase lag element. In this research, we suggest a method to model the gain reduction part in the high-order phase lag element and demonstrate the effectiveness of the model by experiments. Moreover, we demonstrate the practicality of a simple control system design method for technological advances by experiments on perturbation induced by setting the load mass.