Neuromorphic Processing of Pressure Signal Using Integrated Sensor-Synaptic Device Capable of Selective and Reversible Short- and Long-Term Plasticity Operation

Abstract

To mimic the tactile sensing properties of the human skin, signals from tactile sensors need to be processed in an efficient manner. The integration of the tactile sensor with a neuromorphic device can potentially address this issue, as the neuromorphic device has both signal processing and memory capability through which parallel and efficient processing of information is possible. In this article, an intelligent haptic perception device (IHPD) is presented that combines pressure sensing with an organic electrochemical transistor-based synaptic device into a simple device architecture. More importantly, the IHPD is capable of rapid and reversible switching between short-term plasticity (STP) and long-term plasticity (LTP) operation through which accelerated learning, processing of new information, and distinctive operation of STP and LTP are possible. Various types of pressure information such as magnitude, rate, and duration were processed utilizing STP by which error-tolerant perception was demonstrated. Meanwhile, memorization and learning of pressure through a stepwise change in a conductive state was demonstrated using LTP. These demonstrations present unique approaches to process and learn tactile information, which can potentially be utilized in various electronic skin applications in the future.

Emulating the short-term plasticity of a biological synapse with a ruthenium complex-based organic mixed ionic–electronic conductor

“…PPF is a phenomenon of the synaptic enhancement to the second pulse when two presynaptic spikes closely follow. 55–58 For emulating the presynaptic spikes, two 3.5 V pulses (100 ms in duration and 50 ms in interval time) were applied to the OMIEC memristors as shown in Fig. 5b.…”

“…follow. [55][56][57][58] For emulating the presynaptic spikes, two 3.5 V pulses (100 ms in duration and 50 ms in interval time) were applied to the OMIEC memristors as shown in Fig. 5b.…”

Porous Ion Gel: A Versatile Ionotronic Sensory Platform for High-Performance, Wearable Ionoskins with Electrical and Optical Dual Output

“…The superior performance of the porous ion gel-based system was compared to previously reported ion conductor-based sensors regarding their highest sensitivity and maximum detectable pressure range which are usually in a trade-off correlation (Figure b). For example, when flat gel films with good mechanical strength were employed, the detectable pressure limit was found to be broad, but the sensitivity was quite low. ,,, On the contrary, the microstructures of the gel layer provided high sensitivity (>20 kPa –1 ), but the narrow detectable pressure limit was still a weakness. ,,,,,, This work overcomes such limitations using porous ion gels; excellent sensitivity (∼152.8 kPa –1 ) and a wide detection limit (∼400 kPa) were obtained, implying the effectiveness and excellent performance of the elastic porous ion gels.…”

“…The practical applications of ionic capacitive sensors are still limited because of the trade-off between two important metrics, sensitivity and detectable pressure range. , For example, the use of microstructured ion gels ( e.g ., dome, , pyramid, , and wavy shapes) induced dramatic areal changes depending on the applied pressure and significantly improved sensitivity. ,, However, the effectiveness of microstructures is only valid at the low-pressure regime (<∼8 kPa) due to the rapid saturation of the contact area, , causing the narrow operating pressure window. Nonetheless, few strategies have been proposed to address the trade-off in capacitive sensors.…”

“…19,20 For example, the use of microstructured ion gels (e.g., dome, 10,13 pyramid, 11,21 and wavy 22 shapes) induced dramatic areal changes depending on the applied pressure and significantly improved sensitivity. 10,11,21 However, the effectiveness of microstructures is only valid at the low-pressure regime (<∼8 kPa) due to the rapid saturation of the contact area, 23,24 causing the narrow operating pressure window. Nonetheless, few strategies have been proposed to address the trade-off in capacitive sensors.…”