| Résumé | This paper presents the design, finite element modelling, fabrication and performance evaluation of an innovative structure to act as an electro-thermo-mechanical microgripper. The developed microgripper was a micro-electro-mechanical system (MEMS) which couples electrical, thermal and mechanical behaviors to generate tweezing displacements. The actuation principle was based on the electro-thermal effect when the electrical current was converted into heat by Joule's heating causing Topology Optimization Method (TOM) that combines optimization algorithms with the Finite Element Analysis Method (FEM). The optimized microgripper was fabricated from a 25µm thick pure nickel foil using the laser microfabrication technology and its performance was experimentally evaluated using constant current control scheme. The static and dynamic electro-mechanical characteristics were analyzed as step responses with respect to tweezing displacements, applied current/power, and actual resistance. For a microgripper prototype with overall dimensions of 1x2.5 mm, the tweezing displacements of 25.5 µm and 33.2 µm along X and Y axes, respectively, were obtained with an applied power of 2.32 W. Experimental performance was compared with finite element modelling simulation results. These microgrippers may be used in micro-robotics and micro-assembly applications as micro end-effectors for micromanipulating and microhandling operations. |
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