Transfer of motion through a microelectromechanical linkage at nanometer and microradian scales.

Craig R Copeland,Jon Geist,Samuel M Stavis,Vladimir A Aksyuk,Craig D Mcgray

doi:10.1038/micronano.2016.55

Abstract

Mechanical linkages are fundamentally important for the transfer of motion through assemblies of parts to perform work. Whereas their behavior in macroscale systems is well understood, there are open questions regarding the performance and reliability of linkages with moving parts in contact within microscale systems. Measurement challenges impede experimental studies to answer such questions. In this study, we develop a novel combination of optical microscopy methods that enable the first quantitative measurements at nanometer and microradian scales of the transfer of motion through a microelectromechanical linkage. We track surface features and fluorescent nanoparticles as optical indicators of the motion of the underlying parts of the microsystem. Empirical models allow precise characterization of the electrothermal actuation of the linkage. The transfer of motion between translating and rotating links can be nearly ideal, depending on the operating conditions. The coupling and decoupling of the links agree with an ideal kinematic model to within approximately 5%, and the rotational output is perfectly repeatable to within approximately 20 microradians. However, stiction can result in nonideal kinematics, and input noise on the scale of a few millivolts produces an asymmetric interaction of electrical noise and mechanical play that results in the nondeterministic transfer of motion. Our study establishes a new approach towards testing the performance and reliability of the transfer of motion through assemblies of microscale parts, opening the door to future studies of complex microsystems.

Highlights

Control over the output of motion is an essential function of many mechanical systems, so the deterministic transfer of motion through assemblies of parts is of fundamental importance
The measured value of Δθ corresponds to the maximum input voltage applied during the delay, whereas the reported value of Δ(v2) is the value measured at the end of the CONCLUSION In this article, we report the first quantitative measurements of the transfer of motion through a microelectromechanical linkage at nanometer and microradian scales
We develop a novel combination of optical microscopy methods to track the motion of interacting parts in planar microsystems during operation

Summary

Introduction

Control over the output of motion is an essential function of many mechanical systems, so the deterministic transfer of motion through assemblies of parts is of fundamental importance. Mechanisms with moving parts in contact are ubiquitous for this purpose at the macroscale. Challenges involving the operation[1,2,3] and characterization of such mechanisms limit the many potential applications of this technology at the microscale, restricting the functionality of microsystems. These challenges of microsystem technology and motion metrology are at least correlated. As a result of these challenges, modern microsystems commonly incorporate compliant mechanisms[4,5] that eliminate contact between moving parts, but this trend in microsystem design has proceeded without a complete understanding of the limits of operation of rigid-link mechanisms

Methods

Results

Conclusion