Simulation and optimization of a silicon-polymer bimorph microgripper

Abstract

This paper presents an electro-thermally bimorph microgripper based on silicon-polymer laterally stacked structures and a method to optimized the fabricated device. The actuated displacement is enhanced due to the polymer constraint effect. Both the thermal expansion and apparent Young’s modulus of the constrained polymer blocks are significantly improved, compared with the no constraint one. The device consists of a serpentine-shape deep silicon structure with a thin film aluminum heater on the top and filling polymer in the trenches among the vertical silicon parts. The fabricated bimorph microgripper can operate in four modes and generates a large motion up to 15 μm. The simulated results are met the fabricated measurements. An optimized structure is proposed for decreasing the working temperature, power consumption but increasing the output displacement. The simulated results are showed that the output displacement is increased up to 550% and temperature profile improved considerably. This electro-thermally silicon-polymer opened and closed microgripper can be used in micro-robotics, micro-assembly, minimally invasive surgery, living cells surgery.

Design and analysis of a displacement sensor-integrated compliant microgripper based on parallel structure

“…Eq. (14) indicates that the value of the nominal strain is directly proportional to external forces (F), the length of flexure hinge, and inversely proportional to the thickness of flexure hinge, the width of flexure hinge, and the coefficient Young's modulus of the material.…”

“…Recently, integrating a displacement sensor into the gripper was designed by Shafaat et al [11] and Yang et al [12]. Moreover, to ensure reliable and effective performances for compliant microgripper during the grasping process, the stress, displacement, vibration, buckling, failure, and optimization were simultaneously considered [5,10,13,14]. However, an evaluation of the displacement sensitivity of the compliant microgripper has been less interested.…”