3D active stabilization system with sub-micrometer resolution

PLoS One. 2012;7(8):e42733. doi: 10.1371/journal.pone.0042733. Epub 2012 Aug 10.

Abstract

Stable positioning between a measurement probe and its target from sub- to few micrometer scales has become a prerequisite in precision metrology and in cellular level measurements from biological tissues. Here we present a 3D stabilization system based on an optoelectronic displacement sensor and custom piezo-actuators driven by a feedback control loop that constantly aims to zero the relative movement between the sensor and the target. We used simulations and prototyping to characterize the developed system. Our results show that 95% attenuation of movement artifacts is achieved at 1 Hz with stabilization performance declining to ca. 70% attenuation at 10 Hz. Stabilization bandwidth is limited by mechanical resonances within the displacement sensor that occur at relatively low frequencies, and are attributable to the sensor's high force sensitivity. We successfully used brain derived micromotion trajectories as a demonstration of complex movement stabilization. The micromotion was reduced to a level of ∼1 µm with nearly 100 fold attenuation at the lower frequencies that are typically associated with physiological processes. These results, and possible improvements of the system, are discussed with a focus on possible ways to increase the sensor's force sensitivity without compromising overall system bandwidth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electronics / instrumentation
  • Mechanics*
  • Motion*
  • Vibration

Grants and funding

The work was supported by the Academy of Finland grants 118480 and 129762 (to MV), Sigrid Juselius Foundation (to MV and TT), Infotech Oulu Graduate School (to OK), Tauno Tönning foundation (to OK) and Emil Aaltonen foundation (to OK). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.