Light-driven thin-film robots could feel

Biological systems can actively sense and adjust their mechanical response to changes in their environment.

Until now, the mainstream research on biomimetic robotics is to mimic the complex motion of animals and plants, and the developed robots have limited or no sensory capability, one of essential functions of natural intelligence.

It's a grand challenge to achieve highly integrated actuation and sensing function in soft robot body, especially when the robot size is small-scale, down to centimeters.

However, my research team has developed a thin-film robot that compactly integrated a strain sensor, a temperature sensor and an actuator, allowing simultaneous reflex-like and locomotive capabilities.

How does it work?

A flexible thin film with thickness of ~115 μm, includes a bilayer actuator responsive to light heat, pyroelectric polymer layer sensing temperature, and a piezoresistive circuit sensing bending strain.

We tried to detect the robot body temperature and deformation simultaneously, and devised independent electrodes for the two sensors, facilitating separated and non-interfering pyroelectric voltage and piezoresistive resistance read-out signals.

Combining 3-D printing and kirigami techniques, we could selectively print sensing circuits and programmatically pattern the robot shapes, and different robot prototypes can be fast customized and easily downsized.

What can it do?

We developed several kirigami soft robot prototypes for on-demand deployment, and they all display capabilities of proprioceptive and exteroceptive feedback in different situations. A robotic walker provides feedback on its detailed locomotive gaits as well as the subtle terrain textures. An anthropomorphic hand possesses somatosensory receptions, could feel each finger movements and hot/cold touch, and distinguish hardness/softness of different materials. Yet another design is an untethered centipede, can walk, turn, and wirelessly sense light intensity, wind speed and human touch.

What do we expect?

The design principle and robot presented here demonstrate readily manufacturable autonomous and sensory soft-bodied systems. We are now still working with the collaborators to solve the problem of close-loop feedback control between the sensors and actuators, looking toward developing small-sized robots capable of own decisions. We hope to achieve soft robots that can finally work autonomously, response and adapt to changing environments like living organisms.

This story is part of Science X Dialog, where researchers can report findings from their published research articles. Visit this page for information about ScienceX Dialog and how to participate.