Piezoresistive pressure sensor array for robotic skin

Abstract

Robots are starting to transition from the confines of the manufacturing floor to homes, schools, hospitals, and highly dynamic environments. As, a result, it is impossible to foresee all the probable operational situations of robots, and preprogram the robot behavior in those situations. Among human-robot interaction technologies, tactile sensing is an intuitive physical interaction method that can help define operational behaviors for robots cooperating with humans. Multimodal robotic skin with distributed sensors can help robots to increase their perception capabilities according to the surrounding environments.Electro-Hydro-Dynamic (EHD) printing is a flexible multi-modal sensor fabrication method because of its direct printing capability of a wide range of materials onto substrates with non-uniform topographies. In past work we designed interdigitated comb electrodes as a sensing element and printed piezoresistive strain sensors using customized EHD printable PEDOT:PSS based inks. We formulated a PEDOT:PSS derivative ink, by mixing PEDOT:PSS and DMSO. Bending induced characterization tests of prototyped sensors showed high sensitivity and sufficient stability.In this paper, we describe SkinCells, robot skin sensor arrays integrated with electronic modules. 4x4 EHD-printed arrays of strain sensors was packaged onto Kapton sheets and silicone encapsulant and interconnected to a custom electronic module that consists of a microcontroller, Wheatstone bridge with adjustable digital potentiometer, multiplexer, and serial communication unit. Thus, SkinCell's electronics can be used for signal acquisition, conditioning, and networking between sensor modules. Several SkinCells were loaded with controlled pressure, temperature and humidity testing apparatuses, and testing results are reported in this paper.

High Precision 3D Printing for Micro to Nano Scale Biomedical and Electronic Devices

“…Among them, PDMS are suitable for EHD printed electronics. Recent studies focus on fabricating flexible pressure and strain sensor array [143,144], ion-gel-based transistor [145], flexible electrodes [146][147][148], organic thin-film transistor (OTFT) [149,150] etc. Although PEDOT: PSS is commonly used in printed electronics, the ink properties, geometrical pattern and array can be further optimized for targeted applications and multi-modal sensor integration.…”

“…These 3DP techniques have already been demonstrated as effective methods in physical sensors fabrication, with many sensor devices successfully fabricated. The 3DP physical sensors include tactile (touch sensors) [173,204], acoustic sensors [205,206], microcantilever sensors [207], transistors [145,[148][149][150]208,209], strain sensors [143,171,172,210], pressure sensors [66,135,144,151,154,170,211,212] and (piezo resistance, piezoelectricity, capacitance, triboelectricity), photosensors [213][214][215][216]. etc.…”

Inkjet Printing of Functional Inks for Smart Products

“…On the other hand, organic semiconductors can be PEDOT: PSS, rubrene, pentacene, poly(diketopyrrolopyrrole-terthiophene) (PDPP3T), diphenylanthracene (DPA) [43]. PEDOT: PSS and CNT-based composites are vastly used as pressure sensors (piezorresistive materials) [81,82], and temperature sensors (thermoresistive materials) [83,84].…”

Single layered soft skin actuated with twisted and mandrel coiled actuators for soft robotics

“…To enhance the capabilities of artificial skins various sensors embedded within these soft skins have been a part of literature. Mirza et al 32 demonstrated the fabrication and experimental characterization of piezoresistive pressure sensor array for robotic skin. Ha et al 33 reviewed the trends, challenges and perspectives of the importance of soft capacitive pressure sensors and their role in e‐skins.…”