An Image Analysis Approach to Microgrippers Displacement Measurement and Testing

The number of studies on microgrippers has increased consistently in the past decade, among them the numeric simulations and material characterization are quite common, while the metrological issues related to their performance testing are not well investigated yet. To add some contribution in this field, an image analysis-based method for microgrippers displacement measurement and testing is proposed here: images of a microgripper prototype supplied with different voltages are acquired by an optical system (i.e., a 3D optical profilometer) and processed through in-house software. With the aim to assess the quality of the results a systematic approach is proposed for determining and quantifying the main error sources and applied to the uncertainty estimation in angular displacement measurements of the microgripper comb-drives. A preliminary uncertainty evaluation of the in-house software is provided by a Monte Carlo Simulation and its contribution added to that of the other error sources, giving an estimation of the relative uncertainty up to 3.6% at 95% confidence level for voltages from 10 V to 28 V. Moreover, the measurements on the prototype device highlighted a stable behavior in the voltage range from 0 V to 28 V with a maximum rotation of 1.3° at 28 V, which is lower than in previous studies, likely due to differences in system configuration, model, and material. Anyway, the proposed approach is suitable also for different optical systems (i.e., trinocular microscopes).

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

ACTA IMEKO ◽

10.21014/acta_imeko.v10i2.1047 ◽

2021 ◽

Vol 10 (2) ◽

pp. 119

Author(s):

Federica Vurchio ◽

Giorgia Fiori ◽

Andrea Scorza ◽

Salvatore Andrea Sciuto

Keyword(s):

Image Analysis ◽

Angular Displacement ◽

Functional Characterization ◽

Displacement Measurement ◽

Mems Devices ◽

Speeded Up Robust Features ◽

Relevant Today ◽

Measurement Results ◽

Preliminary Study

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, ADMSURF) and FFT-based (Angular Displacement Measurement based on Fast Fourier Transform, ADMFFT) 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 ADMSURF, showed a quadratic trend in agreement with the analytical model. Moreover, the ADMSURF 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 ADMFFT 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.

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Development and Research of a Capacitive Transducer for Angular Displacement Measurement

10.1109/mma52675.2021.9610969 ◽

2021 ◽

Author(s):

Bozhidar Dzhudzhev ◽

Nikolay Stoyanov ◽

Antonia Pandelova

Keyword(s):

Angular Displacement ◽

Displacement Measurement ◽

Capacitive Transducer

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Immersion Birefringent Transducer for Angular Displacement Measurement in Heterodyne Interferometer

CLEO: 2013 ◽

10.1364/cleo_at.2013.jw2a.88 ◽

2013 ◽

Author(s):

Ruey-ching Twu ◽

Ching-Shing Wang ◽

Jhao-Sheng Wang

Keyword(s):

Angular Displacement ◽

Displacement Measurement ◽

Heterodyne Interferometer

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Signal Sampling and Accuracy Analysis of Large Gear’s Angular Displacement Measuring its Deviation On-Machine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.4201 ◽

2011 ◽

Vol 189-193 ◽

pp. 4201-4204

Author(s):

Jia Qi Jin ◽

Hui Li

Keyword(s):

Measurement Accuracy ◽

Angular Displacement ◽

Total Error ◽

Measuring Method ◽

Displacement Measurement ◽

Signal Acquisition ◽

Accuracy Analysis ◽

Friction Disc ◽

Large Gear ◽

Circular Grating

To solve the critical problem of large gear deviation on-machine: angle displacement measurement that is how to get signal acquisition and accuracy analysis of angle displacement. A new measuring method is proposed, which applies the dividing mechanism (it is composed of friction disc and circular grating) to ensure index and pick up signal of gear corner correctly and strictly according to the principle of angular displacement measurement. Furthermore, the main error which affects measurement accuracy is analyzed, and accuracy is analyzed with geometrical theory such as Fourier series and error synthesis principle etc. The experimental results indicate that angel dividing and signal samplings are easier and more efficient by the dividing mechanism, furthermore, the accuracy is in the range of total error that is permitted by verification, and the mechanism can also meet the requirement of high accuracy, so the method is significance that assessing transmission accuracy of involutes gear.

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