By “programming” customized soft materials, a team of researchers from MIT CSAIL can 3D print more durable robots.

Researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have discovered a method to make drones and robots more durable with shock-absorbing, soft skin that protects them from their inevitable falls.

The team’s “Programmable Viscoelastic Material” (PVM) technique allows users to program every single part of a 3D-printed object to the exact levels of stiffness and elasticity that needed for a specific task.

For example, after 3D printing a cube robot that moves by bouncing, the researchers at MIT CSAIL outfitted it with shock-absorbing skins that reduce the amount of energy it transfers to the ground 250 percent.

The researchers say the skins also allow robots to land nearly four times more precisely. They say a similar shock-absorbing skin could extend the lifespan of delivery drones.

“That reduction makes all the difference for preventing a rotor from breaking off of a drone or a sensor from cracking when it hits the floor,” says MIT CSAIL director Daniela Rus. “These materials allow us to 3D print robots with visco-elastic properties that can be inputted by the user at print-time as part of the fabrication process.”

Using a standard 3D printer, the team used a solid, a liquid and a flexible rubber-like material called TangoBlack+ to print both the cube and its skins. The PVM process is related to Rus’ previous 3D printed robotics work, with an inkjet depositing droplets of different material layer-by-layer and then using UV light to solidify the non-liquids.

The cube robot includes a rigid body, two motors, a microcontroller, battery and IMU sensors. Four layers of looped metal strip serve as the springs that propel the cube.

“It’s hard to customize soft objects using existing fabrication methods, since you need to do injection moulding or some other industrial process,” says Hod Lipton, professor of engineering at Columbia. “3D printing opens up more possibilities and lets us ask the question, ‘can we make things we couldn’t make before?'”

The researchers, supported by a grant from the National Science Foundation, will present a new paper (PDF) at the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) in Korea.