Engineers building the next generation of collaborative robots have been trapped in a physical compromise. If we want a robot to have a highly precise sense of touch to grasp a fragile object, we need tiny, densely packed sensor electrodes. But if we want that same robot to sense a human hand approaching from several inches away to avoid a collision, we need large electrodes to project an electric field further outward.
Until now, physics dictated that we could not have both. Small sensors are profoundly nearsighted, while large sensors lack fine resolution.
Researchers at the South China University of Technology have bypassed this fundamental bottleneck by looking to human biology. In the International Journal of Extreme Manufacturing , Prof. Yingxi Xie's team developed a flexible, capacitive sensor array that actively changes its electrical behavior. They achieved this by integrating a dynamic shielding layer over the sensors, a design inspired by the pupillary near reflex of the human eye.
"When we focus on a book, our pupils contract to sharpen the fine details. When we look at a dark and distant road, it dilates to gather more light. We applied this exact logic to electric fields." Dr. Xie explained.
The new dynamic shielding layer sits above the array of full-area electrode units. When the robot needs high-resolution tactile feedback, like feeling the exact edges of a micro-machined part, the shield narrows the electrical focus to the smallest sensing unit by selectively masking the surrounding area. But when the robot needs to look outward to detect obstacles, the shield removes this masking over a much larger area, allowing the underlying electrodes to project a deep sensory field into the surrounding air.
The results represent a massive leap in robotic perception. By decoupling the physical size of the electrodes from how they are electrically connected, the team more than doubled the maximum detection depth, achieving a 104.56% increase over traditional dual-mode sensors.
The sensor can also "feel" an approaching object from more than 90 mm away. In a busy setting, that distance is crucial; it gives a fast-moving robotic arm a vital split-second to halt before striking a human worker.
Once physical contact is made, the sensor's tactile sensitivity remains razor-sharp, capable of registering the whisper-light touch of a few grams or withstanding heavy pressures up to 400 kPa.
However, moving this technology from a controlled laboratory into the punishing environments of modern manufacturing or unpredictable home living rooms presents steep hurdles. To achieve such high tactile sensitivity, the team used a "sacrificial template" method to bake microscopic pores into the sensor's materials.
This process inherently produces randomized and sponge-like structures. While the researchers kept the performance variation between individual sensor units to a manageable 6.3%–6.8% in their prototypes, mass-producing thousands of these arrays with identical reliability will require highly stringent automated screening.
Furthermore, the sensitive nature of capacitive fields makes them highly vulnerable to real-world interference. Electromagnetic noise from heavy machinery, as well as shifting ambient temperatures and humidity, can easily trigger false readings. Before this technology can be widely adopted, the raw hardware will need to be heavily shielded or paired with advanced, real-time machine learning algorithms to filter out the electrical noise of the real world.
If these scaling and environmental challenges can be managed, this dynamic sensor architecture offers a brilliant new blueprint for embodied intelligence. Instead of outfitting robots with redundant, bulky layers of separate proximity cameras and tactile pressure pads, a single and adaptive electronic skin could soon allow machines to successfully transition from perceiving the space around them to safely interacting with the people and objects within it.
International Journal of Extreme Manufacturing (IJEM, IF: 21.3 ) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.
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International Journal of Extreme Manufacturing
A bio-inspired proximity-tactile sensor array with beyond-extreme detection depth for embodied intelligence
13-Feb-2026