Time-division multiplexed thermistor-triboelectric bimodal tactile sensor for material recognition

Abstract

Multimodal tactile perception serves as a foundational technology for advanced human-robot interaction systems. This paper presents a novel time-division multiplexed thermistor-triboelectric bimodal tactile sensor. By dynamically reconfiguring electrical connections, the sensor alternately operates in thermal and triboelectric modes during contact and separation phases, eliminating signal interference. The sensor adopts gold, silver, and platinum electrode arrays, utilizing their distinct thermal conductivity and resistance properties to improve material identification accuracy. In terms of material recognition: During contact, between the sensor and the object, the circuit applies voltage to the thermistor to heat the electrode, raising its temperature above ambient levels to detect the thermal conductivity characteristics of the contacted material. During separation, the circuit switches to reconfigure the thermistor into a single-electrode triboelectric Nano generator (TENG) configuration, capturing the material's electronegativity differences. This time-division multiplexing mechanism enables dual physical signal acquisition without increasing the sensor's size, significantly boosting functional density and recognition accuracy. Experimental validation on eight common materials (including single-sided copper foil tape and single-sided aluminum foil tape) achieved 96.3 % recognition accuracy. Based on these results, the developed material identification testing system achieves real-time material recognition. This work provides a novel technical approach for designing paradigm for robotic tactile perception, offering substantial application potential. Based on the principles of thermistors and triboelectric, and combined with a time-division multiplexing strategy, we developed a compact, flexible dual-functional tactile sensor employing an Au, Ag, and Pt electrode array. This strategy reduces the sensor's volume and eliminates crosstalk between the two modalities. For material identification, during the contact phase, the sensor functions as a temperature sensor to detect the thermal conductivity characteristics of materials; during the separation phase, it switches to triboelectric mode to measure the electronegativity differences of the materials. Using the Conformer model, the system achieved a material recognition accuracy of 96.3 %. • Developed a flexible, compact tactile sensor based on a time-division multiplexing strategy, enabling dual-functionality within a unified structure. • Attained 96.3 % material recognition accuracy by fusing thermal/triboelectric features via Au,Ag and Pt electrode arrays and a conformer model, surpassing unimodal sensors • Enabling interference-low thermal and triboelectric sensing within a single device. • Built a LabVIEW-Python real-time material recognition system to validate the sensor's industrial applicability.