Toward Operations in a Surgical Scenario: Characterization of a Microgripper via Light Microscopy Approach

Abstract

Micro Electro Mechanical Systems (MEMS)-Technology based micro mechanisms usually operate within a protected or encapsulated space and, before that, they are fabricated and analyzed within one Scanning Electron Microscope (SEM) vacuum specimen chamber. However, a surgical scenario is much more aggressive and requires several higher abilities in the microsystem, such as the capability of operating within a liquid or wet environment, accuracy, reliability and sophisticated packaging. Unfortunately, testing and characterizing MEMS experimentally without fundamental support of a SEM is rather challenging. This paper shows that in spite of large difficulties due to well-known physical limits, the optical microscope is still able to play an important role in MEMS characterization at room conditions. This outcome is supported by the statistical analysis of two series of measurements, obtained by a light trinocular microscope and a profilometer, respectively.

Grasping and Releasing Agarose micro Beads in Water Drops

“…Closure can been regulated by applying to the DUT a voltage form 0 V to 24 V, while opening relies on the elastic energy of deformation that makes the system prone to return to its undeformed configuration. From previous investigations [65], 24 V was confirmed to be the maximum limit for the applied voltage.…”

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

“…The first method used in this study, has been the Semi-Automatic one, which for clarity we will call SAMa, widely described in [7], [8] and used in [9]. As illustrated in [7]- [9], the method introduces a measurement uncertainty contribution which corresponds to 0.02 °, at 95% confidence level, evaluated by means of Monte Carlo simulation.…”

“…Once this uncertainty contribution has been evaluated, for each angular displacement, it is then combined following the equation (1). Once uncertainties have been evaluated, a comparison among the three different set of results will be made, following the procedure adopted in [8] and reported in [31]. In practice, the different methods are able to measure the angular displacement of the comb-drive without significant differences if the following condition is verified (6):…”

Design, Fabrication, Testing and Simulation of a Rotary Double Comb Drives Actuated Microgripper

“…Previous studies that concerned the functional characterization of microgrippers showed that these devices exhibit a non-linear behavior since the angular displacement of this kind of capacitive electrostatic actuators is a quadratic function of the supply voltage [ 32 , 39 , 40 , 41 , 42 , 43 ]. The approach used in the previous studies focused on the static characterization of the microgrippers, where the Device Under Test (DUT) was powered with a direct voltage from 0 V to about 24 V and observed by means of a trinocular optical microscope equipped with a digital camera for image acquisition.…”

“…Recently, microgrippers equipped with Conjugate Surface Flexure Hinges (CSFH) [ 31 ] successfully attempted some operations of grasping and releasing Agarose beans in water drops [ 32 ]. More experimental work and simulations have recently shown that the total number of flexures is related to the energy required to deform the structure from neutral to working configurations.…”