Six-legged functioning robot produced by 3D printer (credit Robert Katzschmann).Until now, 3D printing has been limited to various types of solids; however, a new study has shown how to print highly complex hydraulic systems from both solids and liquids that makes it easier to build labs on a chip for medical and pharmaceutical uses, and liquid channels for chemical testing and analysis. In what could be a significant move towards the rapid fabrication of functional machines, such robots also have potential applications in areas such as facilitating disaster relief in dangerous situations.
Scientists from the Computer Science and Artificial Intelligence Laboratory at MIT automatically produced 3D printed dynamic robot bodies and parts that needed no previous assembly from a commercially available multi-material 3D inkjet printer based on only a single-step process. Using a 3D printer to produce robots is a viable alternative to doing so by hand, which requires huge effort, or through automation, which has not yet reached the necessary level of sophistication. This “printable hydraulics” approach, which provides a design template that can be tailored for robots of different sizes, shapes and functions, was used to produce a small six-legged robot with a dozen hydraulic pumps embedded within it, only requiring the minimal addition of the electronics and a battery before being operational.
“3D printing offers a way forward, allowing us to automatically produce complex, functional, hydraulically powered robots that can be put to immediate use”Daniela Rus
As team leader Daniela Rus points out, “3D printing offers a way forward, allowing us to automatically produce complex, functional, hydraulically powered robots that can be put to immediate use”. Such printable robots could also be quickly and cheaply produced, and have less electronic components than standard robots. A paper on their research was recently accepted for the 2016 IEEE International Conference on Robotics and Automation (ICRA).
In the technique, the printer deposited individual droplets of material of only 20–30 microns in diameter, by layer from the bottom up, with different materials being deposited in different parts for each layer. A high-intensity UV light then solidified the materials but not the liquids. The printer can use many types of material, although each layer is made up of a photopolymer that is solid and a non-curing material that is liquid.
They showcased the technique by 3D printing linear bellows actuators, gear pumps, soft grippers as well as the hexapod robot. The hexapod weighed about 1.5 pounds and was under six inches long, and moved using a single DC motor turning a crankshaft that pumps fluid to the robot’s legs. However, it took 22 hours to print, not long considering its complexity, but the team hopes this can be achieved faster by improving on the engineering and resolution of the printers.