Serially Connected Weight-Balanced Digital Actuators for Wide-Range High-Precision Low-Voltage-Displacement Control

Abstract

This paper presents the design, fabrication, and characterization of a new serial digital actuator, achieving an improvement in range-to-precision and range-to-voltage performance. We propose a weight-balanced design for the serial actuators with serpentine springs with a serial arrangement of unit digital actuators. We have measured the displacement range, precision, and drive voltage of unit and serial actuation at 1 Hz. The serial digital actuators produce a full-range displacement of 28.44 plusmn 0.02 mum , accumulating unit displacements of 2.8 plusmn 0.5 mum at an operating voltage of 4.47 plusmn 0.07 V. In addition, the serial digital actuators that have a displacement precision of 37.94 plusmn 6.26 nm do not accumulate the displacement errors of the unit actuators, i.e., 36.0 plusmn 17.7 nm. We experimentally verify that the serial digital actuators achieve a range-to-squared-voltage ratio of 1.423 mum/V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a range-to-precision ratio of 749.6.