A high-resolution, ultrabroad-range and sensitive capacitive tactile sensor based on a CNT/PDMS composite for robotic hands

Tactile sensors are of great significance for robotic perception improvement to realize stable object manipulation and accurate object identification. To date, developing a broad-range tactile sensor array with high sensitivity economically remains a critical challenge. In this study, a flexible capacitive tactile sensor array, consisting of a carbon nanotube (CNT)/polydimethylsiloxane (PDMS) film, parylene films, and two polyimide (PI) films patterned with electrodes, is facilely prepared. The CNT/PDMS film, acting as a giant dielectric permittivity material, is utilized to improve the sensitivity, while the parylene film serves as the scaffold architecture to extend the working range of the tactile sensor array. Also, it is promising to realize mass production for this sensor array due to the scalable fabrication procedure. The as-prepared sensor exhibits excellent sensing performance with a high sensitivity of 1.61% kPa-1 (<1 MPa), an ultra-broad pressure working range of 0.9 kPa-2.55 MPa, an outstanding durability, a stability up to 5000 cycles, and a fast response time. By integrating our tactile sensor array with a robotic gripper, we show that robots can successfully differentiate object shapes and manipulate light and heavy objects with a closed-loop pressure feedback, demonstrating its great potential in robotic perception and wearable applications.