Robots are many things, including expensive and imperfect. Put those latter two together and you’ve got a recipe for disaster, but researchers at MIT are hoping to make robots more resistant to damage with 3D printed shock-absorbing skins. By varying the stiffness of material as it’s made, scientists can create a bumper that absorb energy in more efficient ways.
The team from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) calls this a programmable viscoelastic material (PVM). The printer allows a material to be created with multiple materials, each with different mechanical properties. This is the “programming” referred to in the name. It doesn’t even require a new kind of 3D printer. The team was able to use a standard printer to deposit a solid, liquid, and flexible rubber-like material called TangoBlack in their designs.
Having precise control over the dampening capacity of the a robot’s skin allows customization that would usually be impractical. Conventional dampening materials are only available in specific sizes and levels of softness. You might be able to protect a robot with that, but the material could easily be too soft or too hard in places to offer optimal protection. If you can make custom dampening material, it can be tuned to the specific application.
As a test, the team designed a simple cube-shaped flipping robot. It has a rigid body, two motors, a microcontroller, some sensors, and a battery. Covering the cube is a PVM created by the team with a flexible outer layer, a solid internal structure, and pockets of liquid. Because this liquid is sealed and doesn’t cure, the material retains its programmed viscoelasticity.
When the cube uses its motors to flip itself, it lands with very little bounce. All that energy is absorbed by the skin, rather than shocking the robot and causing it to bounce. Without the custom PVM layer, a similar robot was only able to land with one-quarter of the accuracy. That is, it bounced around a lot more — not a good thing if you’re talking about an expensive robot that can be damaged by such a tumble. The robot with PVM skin recorded only 1/250 the amount of energy internally as it transferred to the ground.
The researchers envision PVM materials as coverings for flying delivery drones, robotic warehouse workers, and more. The potential applications don’t stop with robots, though. It’s possible to create custom programmable viscoelastic materials for helmets that more effectively protect the head, or running shoes that transfer less energy into the wearer’s feet.