Dual-mechanism layered ionic skin: For quick touch position sensing and high-precision touch intensity detection

Achieving high-precision integrated detection of touch position and intensity is a major problem for intelligent sensing technologies in the domains of intelligent robots and human-computer interaction (HCI). Discrete structures found in popular array-type sensors nowadays add to the system's structural complexity. Even though current layered structural designs have made significant strides in streamlining the architecture, they are unable to meet the practical demands of high-precision interaction because they rely on a single sensing mechanism to identify both position and intensity simultaneously, which leaves them vulnerable to signal crosstalk. Thus, this study suggests a dual-mechanism layered ionic skin (DM-LIS). The lower capacitive sensing layer (CSL) builds a dual-capacitor structure using ionic gel-infused porous sponge to achieve high-precision touch intensity detection, while the upper resistive positioning layer (RPL) realises touch position recognition based on graphite conductive adhesive coated on a sandpaper microstructure. By sharing a sandpaper substrate, the two layers are merged, significantly streamlining the device's overall design. According to experimental data, this dual-mechanism layered ionic skin has a touch position reaction time of 18 ms at a resolution of 5 mm. Its dual method for detecting touch intensity is 0.356 kPa^-1. The sensor can achieve synchronous and high-precision detection of the position and intensity information of mechanical stimuli by independently gathering capacitive and resistive signals. Furthermore, no matter what combination of commands is used to operate the Tetris game, the intelligent keyboard built on top of this ionic skin can drive the blocks to produce precise responses. In summary, this study's dual-mechanism layered ionic skin offers a workable technical solution for the synchronous detection of pressing intensity and tactile location data, and it has substantial potential applications in the high-precision HCI space.