NUS researchers develop wireless, ultra-thin and battery-free strain sensors
A research team from NUS, led by Assistant Professor Chen Po-Yen, has taken the first step towards improving the safety and precision of industrial robotic arms by developing a new range of nanomaterial strain sensors that are 10 times more sensitive when measuring minute movements, compared to existing technology.
Fabricated using flexible, stretchable, and electrically conductive nanomaterials called MXenes, these novel strain sensors developed by the NUS team are ultra-thin, battery-free and can transmit data wirelessly. With these desirable properties, the novel strain sensors can potentially be used for a wide range of applications.
One area where the novel strain sensors could be put to good use is in precision manufacturing, where robotic arms are used to carry out intricate tasks, such as fabricating fragile products like microchips.
These strain sensors developed by NUS researchers can be coated on a robotic arm like an electronic skin to measure subtle movements as they are stretched. When placed along the joints of robotic arms, these strain sensors allow the system to understand precisely how much the robotic arms are moving and their current position relative to the resting state. Current off-the-shelf strain sensors do not have the required accuracy and sensitivity to carry out this function.
Conventional automated robotic arms used in precision manufacturing require external cameras aimed at them from different angles to help track their positioning and movement. The ultra-sensitive strain sensors developed by the NUS team will help improve the overall safety of robotic arms by providing automated feedback on precise movements with an error margin below one degree, and remove the need for external cameras as they can track positioning and movement without any visual input.
The technological breakthrough is the development of a production process that allows NUS researchers to create highly customisable ultra-sensitive sensors over a wide working window with high signal-to-noise ratios.
A sensor’s working window determines how much it can stretch while still maintaining its sensing qualities and having a high signal-to-noise ratio means greater accuracy as the sensor can differentiate between subtle vibrations and minute movements of the robotic arm.
This production process allows the team to customise their sensors to any working window between 0–900 per cent while maintaining high sensitivity and signal-to-noise ratio. Standard sensors can typically achieve a range of up to 100 per cent. By combining multiple sensors with different working windows, NUS researchers can create a single ultra-sensitive sensor that would otherwise be impossible to achieve.
The research team took two years to develop this breakthrough and have since published their work in the scientific journal ACS Nano in September 2020. They also have a working prototype of the application of the soft exoskeletons in a soft robotic rehabilitation glove.
The team is also looking to improve the sensor’s capabilities and work with the Singapore General Hospital to explore the application in soft exoskeleton robots for rehabilitation and in surgical robots for transoral robotic surgery.
(Content Courtesy: https://news.nus.edu.sg/ultra-thin-and-highly-sensitive-strain-sensors/)