DERMIS: End-to-End Design of a Fully Integrated Large-Area Grasp-State-Adaptive Tactile Sensor System on a-IGZO TFT

This paper presents the design of a high-resolution fully-integrated tactile sensor system, called DERMIS, implemented in a flexible thin-film transistor (TFT) technology for large-area electronic skins. It discusses how an end-to-end design strategy - from the sensor to the readout and to the on-chip feature extraction - enables efficient system reconfiguration to implement a first-of-its-kind and biologically-inspired grasp-state-adaptive tactile sensor. In contrast to existing tactile sensors that only detect slip, the DERMIS system also measures key contact cues, including friction, contact onset/offset, and lift-off onset/offset, enabled by a novel differential capacitive sensor structure that independently senses shear and normal forces and a co-designed front end that directly extracts both components at the analog domain. Furthermore, due to the analog-based encoding of these grasp-state-dependent contact parameters, the system avoids the use of complex offline slip-extraction algorithms. The per-taxel (tactile pixel) readout consumes a state-of-the-art 72 $\mu$W power consumption and occupies 0.36 mm${}^{2}$ area while achieving a human-like 2 mN${}_{RMS}$ force resolution at 0.6 mm pitch. This work demonstrates our solution for the first time in a true large-area prototype of 9$\times$ 4 mm${}^{2}$.