Comparative evaluation of three image analysis methods for angular displacement measurement in a MEMS microgripper prototype: a preliminary study

Abstract

<p class="Abstract"><span lang="EN-US">The functional characterization of MEMS devices is relevant today since it aims at verifying the behavior of these devices, as well as improving their design. In this regard, this study focused on the functional characterization of a MEMS microgripper prototype suitable in biomedical applications: the measurement of the angular displacement of the microgripper comb-drive is carried out by means of two novel automatic procedures, based on an image analysis method, SURF-based (Angular Displacement Measurement based on Speeded Up Robust Features, ADM<sub>SURF</sub>) and FFT-based (Angular Displacement Measurement based on Fast Fourier Transform, ADM<sub>FFT</sub>) method, respectively. Moreover, the measurement results are compared with a Semi-Automatic Method (SAM), to evaluate which of them is the most suitable for the functional characterization of the device. The curve fitting of the outcomes from SAM and ADM<sub>SURF</sub>, showed a quadratic trend in agreement with the analytical model. Moreover, the ADM<sub>SURF</sub> measurements below 1° are affected by an uncertainty of about 0.08° for voltages less than 14 V, confirming its suitability for microgripper characterization. It was also evaluated that the ADM<sub>FFT</sub> is more suitable for measurement of rotations greater than 1° (up to 30°), with a measurement uncertainty of 0.02°, at 95% of confidence level.</span></p>

First results on the functional characterization of two rotary comb-drive actuated MEMS microgripper with different geometry

“…UNCERTAINTY ANALYSIS In order to discuss the obtained results, an uncertainty analysis considering the main sources of uncertainty has been carried out. In according with the approach adopted in [13][14][15], Type A and Type B uncertainties have been combined [19], following: Type A uncertainties σA have been evaluated considering the standard deviation of the obtained results, while Type B uncertainties σB have been calculated by taking into consideration the following sources of uncertainty present in the measurement chain, listed in Table 3: x Arbitrary/Function Generator on signal amplitude and frequency, reported in the datasheet. x Power amplifier uncertainty on amplitude, reported in the datasheet.…”

“…The MG prototypes under examination are equipped with electrostatic rotary comb-drives and Conjugate Surface Flexure Hinges (CSFHs) and fabricated monolithically on a Silicon-on-Insulator (SOI) wafer with an aluminum hard mask, through a process of Deep Reactive Ion Etching (DRIE) [9][10]. Previous studies available in literature [11][12] have presented a theoretical formulation describing the electrostatic torque exerted by rotary comb-drives, which is a function of the geometric characteristics of the micro-actuator, whose nominal values have been reported in Table 1, and the square of the supply voltage and have evaluated the displacement as a function of the latter [13][14][15]. This preliminary study, based on image analysis method, aims to investigate the design of MG prototypes by analyzing the relationship between gripper tips displacement and the number of active micro-actuators, as a function of supply voltage and to verify if doubling the electrostatic torque applied by the comb-drives, the prototype displacements double, as assumed by the theoretical model [9][10][11][12].…”

A Comparative Study on a Novel Quality Assessment Protocol Based on Image Analysis Methods for Color Doppler Ultrasound Diagnostic Systems

“…The measurement uncertainty contribution due to the image analysis-based methods was estimated through the Monte Carlo Simulation [47], a proper and robust tool already experienced in previous studies [43,48,49]. An MCS with 10 4 iterations was run for each combination of test parameters, US systems, and probes, as well as configuration and phantom settings.…”

First results on torque estimation by FEA and experimental analysis in a novel CSFH-based microgripper

“…The present work focuses for the first time on a novel CSFH-based MG equipped with only one CSFH pair, with the aim of investigating the mechanical behavior of the hinges by means of experimental analysis, based on image analysis method [15], and Finite Element Analysis (FEA), evaluating the torque exerted by electrostatic microactuators. A supply voltage in the 0-20 V range has been considered for the Device Under Test (DUT), whose main parameters are listed in Table 1.…”