A new, "soft" material can help land drones morph into flying wonders

A research team at Virginia Tech has developed a new material that can be morphed at will and be used to convert a land vehicle into an aerial one, a university press release said.

The research team led by Assistant Professor Michael Bartlett took inspiration from nature where living organisms constantly change their shape to perform different functions and then revert back to their original form. The human muscle is a prime example of how it undergoes shape changes multiple times a day.

Instead of creating soft robots that perform a particular function, the team decided to develop a material that would be soft enough to be morphed into a new shape but still be rigid enough to create a machine that could perform different functions.

Kirigami to the rescue

Interestingly, the team found their answer in the Japanese art form of kirigami, which involves cutting shapes out of paper, instead of folding them as done in origami. The researchers found that rubber and composite material offered the same strength as kirigami patterns but needed a material that could be morphed at will. 

So they introduced a low melting point alloy (LMPA) endoskeleton inside the rubber skin. The outer rubber coating also protected the alloy from cracking and bending into an undesirable shape when heated. However, the material also had to be returned to its original shape. To facilitate this reversal, the team introduced soft heaters next to the LMPA mesh that could change the metal into its liquid form at a low temperature of 140 degrees Fahrenheit (60 degrees Celsius) to return the structure to its original shape. 

The researchers found that using this setup they could not only make a wide range of complex shapes but also change them quite quickly. An additional benefit of the rubber exoskeleton was that it helped in "healing" the material, just in case it broke during their experiments. All they needed to do was heat the LMPA and it would set back into shape soon after it cooled down. 

Future applications

The team paired up their newly engineered material with motors, onboard power, and control systems to make a functional land drone that could autonomously be morphed into an aerial one. In addition to this, the team also created a submersible drone that used its morphing capabilities to retrieve objects from the bottom of a water body.

Apart from this, the team is excited that their material can be used to create machines and soft robots that can perform diverse functions, have increased resilience due to their ability to heal themselves, and find new applications in wearable devices.  

The study was published recently in Science Robotics.