Researchers at the University of California San Diego and Seoul National University have released details of a scalable, tactile sensor array built on top of a flexible substrate and designed to offer rapid grip force adjustment in closed-loop robotic systems.
"We report large-scale and multiplexed tactile sensors with submillimeter-scale shear sensation and autonomous and real-time closed-loop grip adjustment," the researchers explain in the abstract to their paper. "We leveraged dual-gate piezoelectric zinc oxide (ZnO) thin-film transistors (TFTs) fabricated on flexible substrates to record normal and shear forces with high sensitivity over a broad range of forces."
"An individual ZnO TFT can intrinsically sense, amplify, and multiplex force signals, allowing ease of scalability for multiplexing from hundreds of elements with 100-μm spatial and sub–10-ms temporal resolutions. Notably, exclusive feedback from the tactile sensor array enabled rapid adjustment of grip force to slip, enabling the direct autonomous robotic tactile perception with a single modality. For biomedical and implantable device applications, pulse sensing and underwater flow detection were demonstrated. This robust technology, with its reproducible and reliable performance, can be immediately translated for use in industrial and surgical robotics, neuroprosthetics, implantables, and beyond."
The team have already demonstrated some of these potential applications for the sensor system, showcasing the sensor being fitted to robotic fingers for closed-loop grip and shear-force feedback while lifting and gripping fragile objects prone to slippage, a downscaled variant with ultra-high-resolution for both spatial and temporal sensing, and miniaturized arrays for pulse sensing, blood pressure monitoring, and flow detection — the latter also showcasing the sensor's waterproof nature.
"This research offers a general route to construct flexible normal and shear force sensing components that can be readily integrated in robotic applications for closed-loop operated delicate manipulations," the team concludes. "In addition, the TFT tactile arrays can provide 3D information on the applied force when integrated to current consumer electronics that operate on the touch principle in mobile devices, gaming gears, or musical instruments, even under wet environments. Last, flexible form factor and free dimension scaling promise its applications in future technologies such as biomedical equipment, surgical robots, microflow meters, and implantable devices."
The work has been published in the journal Science Advances under open-access terms.