Design and characterization of an electrostatic constant-force actuator based on a non-linear spring system

Thewes, A.C. and Schmitt, P. and Löhler, P. and Hoffmann, M.

Volume: 10 Pages:
DOI: 10.3390/act10080192
Published: 2021

In recent years, tissue engineering with mechanical stimulation has received considerable attention. In order to manipulate tissue samples, there is a need for electromechanical devices, such as constant-force actuators, with integrated deflection measurement. In this paper, we present an electrostatic constant-force actuator allowing the generation of a constant force and a simultaneous displacement measurement intended for tissue characterization. The system combines a comb drive structure and a constant-force spring system. A theoretical overview of both subsystems, as well as actual measurements of a demonstrator system, are provided. Based on the silicon-on-insulator technology, the fabrication process of a moveable system with an extending measurement tip is shown. Additionally, we compare measurement results with simulations. Our demonstrator reaches a constant-force of 79 ± 2 µN at an operating voltage of 25 V over a displacement range of approximately 40 µm, and the possibility of adjusting the constant-force by changing the voltage is demonstrated. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

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