Balanced High-Sensitivity and Wide-Range Flexible Sensor for Human-Machine Interaction

Abstract

The pursuit of balanced performance encompassing high sensitivity, a broad detection range, and excellent durability remains a core challenge for the practical application of flexible piezoresistive sensors. This study reports a sandwich-structured flexible piezoresistive sensor, which utilizes a carbonized reduced graphene oxide film (C-rGOF) as the core sensing material and is encapsulated with polydimethylsiloxane (PDMS, denoted as C-rGOF@PDMS). The sensor is fabricated via a hydrazine hydrate-assisted gradient foaming strategy combined with high-temperature carbonization, resulting in a C-rGOF sensing core with a uniform and stable 3D porous structure. The device achieves a combination of key performance metrics: a high sensitivity of up to 122 kPa–1, a broad detection range of 0.01–1300 kPa, a fast response/recovery time of 70/52 ms, an ultralow detection limit of 100 mg, and stable cyclic performance exceeding 40,000 cycles at 1 kPa. Thanks to these properties, the sensor accurately captures a wide spectrum of human motions, including subtle physiological activities such as frowning and swallowing to dynamic joint movements including those of the elbow and knee. By integrating a 4 × 4 sensor array and implementing a column-by-column scanning circuit strategy, signal crosstalk was effectively suppressed, enabling dynamic spatial pressure mapping. Furthermore, an integrated tactile glove system centered around an Arduino controller was developed, which successfully translated common hand gestures, including numerals 1 through 5, a finger-heart gesture, and fist clenching, into stable and precise control of a bionic robotic hand. This work, which progresses from material design to system integration, provides a paradigm for constructing high-performance, low-cost, and scalable flexible tactile systems, with potential for applications in medical rehabilitation, intelligent prosthetics, and remote manipulation.