Optimal design of high bandwidth piezo-based nanopositioners employing bridge-type displacement amplifiers *

Abstract

Piezo-based nanopositioners are widely employed in precision positioning applications. This paper proposes the design, modeling, and optimization of high bandwidth nanopositioner, whose design reduces the effect of the mass of the sample on its bandwidth and achieves greater bandwidth than a piezo actuator of the same range. The nanopositioner’s range is improved by employing bridge-type displacement amplifiers, while its bandwidth is improved by minimizing the inertial loading of the sample on each of the parallelly connected amplifiers. An analytical model is developed, and the closed-form expressions for amplification ratio and bandwidth of nanopositioner are derived and then validated using finite element analysis. The results of amplification ratio and bandwidth of the positioner match within an average error of 3%. Finally, the optimal number of amplifiers and their corresponding tilt angle required to achieve the maximum bandwidth for the desired positioning range is discussed. It is shown that as the range increases, higher bandwidths can be achieved with the proposed design. In particular, for the 100 μm range, the positioner’s bandwidth is improved by a factor of 6.5 compared to just a piezo actuator moving the same sample.