Benefits of amplification in an inertial stepping motor

Inertial stepping motors (ISMs) are widely used in high precision applications, such as scanning tunnelling microscopy and/or micro manipulation. The resolution they are able to reach makes them especially suitable when long stroke and high resolution are needed simultaneously. However, the limited speed of this technology is its main drawback. To overcome this drawback, the present paper proposes to use an amplified actuator in an ISM instead of a classical direct actuator. The impact of this choice is studied here, from speed and electrical current points of view. This study determined in an analytical way the influence of the actuator stroke on the step size of an ISM via an optimised control signal. The results are then confronted to a lumped model to identify potential limitations. Finally, a test bench is built using three different piezoelectric actuators to obtain experimental feedback about the benefits of actuator amplification in ISMs. (C) 2012 Elsevier Ltd. All rights reserved.