Electromechanically stable and flexible poro-hyperelastic composites for multimodal robotic tactile sensing

Abstract

The expansion of automated production places increased demands on sensory networks for collecting input signals, which necessitate higher standards for multimodal detection, sensitivity, and sensing response speed. Here, this work developed a multimodal flexible tactile sensor capable of triboelectric, piezoresistive, and capacitive modes across multiple strains and frequencies. The multilayer flexible multimodal mechano-electronical sensor (MMES) is constructed from a carbon nanotubes porous sponge (CNPS), facilitating switching between trimodal sensing modes integrated within a single sensor structure, effectively enhancing electromechanical stability of the sensor. The present MMES sensor exhibits excellent pressure sensing performances, with a wide range (0-20 kPa), fast response (less than 102 ms in piezoresistive mode and less than 62 ms in capacitive mode), high sensitivity (up to 0.56 kPa⁻1 in triboelectric mode), and long-term durability (exceeding 10,000 cycles). Moreover, a micro-CT generated 3D models was established using finite element analysis (FEA) to investigate porous hyperelastic behaviors of the CNPS composites, in agreement with experimental data. The results demonstrated that such the MMES sensor is particularly suitable for dynamic feedback in robotic arms, allowing production lines to make accurate distinguishments and operations by sensing distinct materials and resistances encountered during assembly in real-time. The outcomes offer promising applications of multimodal tactile sensing for human-machine interaction.