A preliminary study on the dynamic characterization of a MEMS microgripper for biomedical applications

This preliminary study concerns the dynamic characterization of a MEMS microgripper for biomedical applications. In particular, a prototype of microgripper, embedded with electrostatic comb-drive actuators, has been powered with a 10V sinusoidal input at different frequencies, 0.5 Hz, 1.0 Hz and 4.0 Hz. The response of the device has been recorded with a trinocular optical microscope, equipped with a digital camera and the recorded videos have been analysed with an in-house software implemented by the authors for the measurement of the comb-drive angular displacement, velocity and acceleration. The uncertainty analysis has been carried out to identify the uncertainty sources that characterize the measurements. Experimental data showed that the maximum angular displacement is (13.2 ± 0.2)•10-3 rad, (13.6 ± 0.2)•10-3 rad and (13.1 ± 0.3)•10-3 rad, the maximum angular velocity is (2.8 ± 0.2)•10-2 rad/s, (5.7 ± 0.4)•10-2 rad/s and (19.9 ± 1.5)•10-2 rad/s, and the angular acceleration is 0.178 ± 0.015 rad/s2, 0.72 ± 0.04 rad/s2 and 6.3 ± 0.7 rad/s2 for 0.5 Hz, 1.0 Hz and 4.0 Hz, respectively. The measurement results have been compared with the expected values from the theoretical model that describes the behaviour of the microgripper: the overall percentage error (PE) between the measured and the expected values at different frequencies is lower than 1%, 1% and 3% for the angular displacement, velocity and acceleration respectively.