Soft robots 3D-printed in sub-millimeter sizes

The future of robotics might not be the industrial, metallic kind we are used to. Researchers at Linköping University are making strides in soft robotics, reaching smaller and smaller milestones for the field.

Photo of microrobot. This microrobot is 3D-printed in a lab at the Bionics and Transduction Science unit.  Olov Planthaber

We are all familiar with conventional robots, heavy arms of solid metal running on electric motors. Maybe for assembling a car. They have served humanity well but are very limited in relation to the human body.
– You don’t want these factory robots to lift your grandma from her bed, says Edwin Jager, associate professor and head of the Bionics and Transduction Science unit at LiU.

  Nanorobot tillsammans med en legogubbe.A Lego-figure compared to two microrobots.In a recent paper published in Soft Robotics (SoRo), he and PhD student Manav Tyagi, together with their collaborator Geoff Spinks at University of Wollongong, Australia, present their latest progress in soft microrobotics. The new microrobots have a rectangular polymeric body with flexible microactuators attached, like limbs.
– The 3D printed gel based limbs comprising conducting polymers can be moved by electrically actuating them, says Manav Tyagi.

But the small size is what really matters, 300 x 1000 micrometers, with a thickness of 20 micrometers.
– It is the smallest 3D printed microrobot, almost tenfold smaller than the previously reported, smallest printed microrobot, so far, says Manav Tyagi. 

 That is a small robot, even for a microrobot, and it was created with a simple 3D printer.
– This is the most exciting part of this paper. We could scale down the robots this much, using a custom built, in-house, 3D printer, says Manav Tyagi.
Edwin Jager is also very pleased with how simple the process has become now.
– Twenty years ago, I did my PhD thesis on microrobots, using complex microfabrication, processed in a “clean room”. Twenty years later, we can create microrobots much easier.

Edwin Jager has seen a lot of progress in his 20 years of research.But how can these robots be used? Potential applications are many, and Manav Tyagi predicts one area were soft robots might have a bright future.
– Conventional robots lack compliance. For example, in health care, you often don’t want rigidity. This could, for example, be used to create realistic prosthetics.

Even microsurgery could use soft microrobots in the future.
– A soft microrobot is flexible and compliant and thereby is less invasive. Think of an octopus that can get through a hole much smaller than they are. In surgery a microrobot with that ability could be very useful, says Manav Tyagi, bringing up octopi, an animal that is an inspiration to the field of soft robotics.

With this paper the Bionics and Transduction Science unit is showing the science community that they are one step closer, but there is a lot of work still left to be done before anyone uses these robots on humans.
– Right now, we have 3D printed microrobots that can potentially be used for gripping, releasing, or even walking, says Manav Tyagi.

For now, the robots can do this submerged in liquid. A long-term goal is to achieve the same movements in air.
– That, and to integrate microchips to grant these robots electronic intelligence, says Edwin Jager.

Manav Tyagi and Edwin Jager.

Download the open access paper here.

Microrobots move in liquid

Researchers at LiU have created the smallest 3D-printed robot in the world. 

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