Building a robot is hard. Building one that can sense its environment and learn how to get around on its own is even harder. But UCLA engineers took on an even bigger challenge. Not only did they create autonomous robots, they 3-D printed them in a single step. Each robot is about the size of a fingertip.

It just got a little easier to create soft robots that adapt to the world around them. Rice University researchers have developed a 3D printing technique (they call it "4D") for material that automatically changes to an alternate shape when subjected to an electric current, changes in temperature or simple stress. The team produced a liquid crystal polymer'ink' with two exclusive sets of molecular links -- one with the originally printed shape, and another by manipulating the material. In this case, scientists just had to heat or cool the material to flip it between a flat surface and a bumpy one, among other changes. The challenge was to craft a polymer mix that could be printed in a catalyst bath without losing its shape, Rice said.

Imagine you could use a standard 3D printer to create your next robotic assistant. Just snap in a motor and battery, and it's ready to go. That's precisely the scenario made possible by a new 3D printing technique developed at MIT. Liquids have long been a challenge for 3D printing, and they're necessary for hydraulic devices like moving robots. On Wednesday, researchers at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) announced what they call the first-ever technique for 3D printing robots that can print solid and liquid materials at the same time. That means it's possible to print dynamic robots in a single step, using a commercially available 3D printer.

The machines are now making machines of their own, and there's no assembly required. Researchers in the US have developed 3D-printed robots containing solid and liquid parts which only need to be connected to a motor and power supply before they can scuttle off. By laying down all the components as it goes, the 3D printer can produce the robot's rigid support, flexible components and fluid filled channels as it builds up the layers. Researchers at MIT have developed a 3D printing technique for producing hydraulic components. The method makes it possible to print robots with hydraulic parts, simplifying the production process so even a novice can print their own robot. So far the team at Massachusetts Institute of Technology has printed a range of components, as well as a fully-printed six-legged bug-bot which can scuttle away on its rubbery limbs, and a soft gripper for picking up objects.