Electrothermal microgripper with large jaw displacement and integrated force sensors

This paper presents a novel sensing microgripper based on silicon-polymer electrothermal actuators and piezoresistive force sensing cantilever beams which can monitor the displacement of the microgripper jaws and also the contact force between the tips and the gripped object. A jaw motion up to 32 μm with an output sensing voltage of 49 mV and 114 mW power consumption is measured at a driving voltage of 4.5 V. The working temperature of the structure is then 177 °C. The force sensitivity is 1.7 V/N and the corresponding displacement sensitivity is 1.5 kV/m. A minimum detectable displacement and a minimum detectable force of 1 nm and 770 nN are estimated, respectively.