How to Make a Soft Robot

By Kate Knibbs on at

Robots are often imagined as hard, shiny things, gleaming futuristic machines. They often are hard, shiny things. But sometimes they're soft and flexible, instead. Soft robotics is a growing field devoted to the squishier side of automated technology, and with the help of a new toolkit, you can get in on the action.

So wait, soft robots are just stretchy robots?

Yep, pretty much. They are robots with frames and actuators made from malleable materials. The big thing that distinguishes them from their hard-robot counterparts is the material used, although many soft robotics projects are explicitly inspired by nature in a way that seems at odds with the largely mechanical goals of mainstream robotics.

Gizmodo has written about a variety of soft robots in the past, from a crawling inflatable silicon bot to a light-controlled gel to an artificial octopus with silicon webbing. Did I mention "bio-bots" made of 3D printed hydro-gels meant to travel through your body? Soft robotics innovations are happening at a quick pace.

DIY soft robot heaven is a place on the internet

And researchers want to speed up that pace even further.

Harvard's School of Engineering and Applied Sciences recently published an open-source soft robotics toolkit to help DIY fans and robotics researchers craft their own. It is damn thorough, providing step-by-step instructions on how to make a variety of different designs, including a robotic hand:

If you're looking at this hand and thinking "there's no way in hellll I could make that", fair enough. That is also what I thought. While the instructions are explicit, making the moulds and constructing your own prototype is definitely only for the skilled makers.

This hand, for instance, requires makers to create two types of moulds for the working hard and soft parts, and it leaves it up to the makers to decide how they will operate the fingers once they make them. Not exactly for novices.

A few of the other designs are simpler, like PneuNets Bending Actuators, a type of robotic frame made of two parts that can be constructed relatively easily if you have access to a 3D printer. The instructions are very precise. This is one of the tutorial videos provided for people designing their frame:

What are they made of, exactly?

There are a variety of pliable materials used in soft robotics. The big focus is on elastomers, a type of polymer that can bend. For that PneuNets actuator, the instructions simply advised that people use elastomers, but that leaves a wide range of choices. Silicon is the most popular option.

Some soft robots have frames that are entirely soft, while others (like the grippy fingers) have a mix of hard and soft materials. And the soft robotics field is becoming increasingly accessible. See for example the interlocking Lego-esque inflatable bricks made to help people assemble custom soft robotics quickly.

What can you use them for?

Depends on what do you want to do. Right now, the open-source kit is hoping to get more people to actually manage to build one and help answer that question. Harvard sees a lot of potential, including interacting with humans, since they're ostensibly safer, anything from "assisting with daily activities to performing minimally invasive surgery."

Right now, these machines are mainly developed in labs and as prototypes. There's no huge soft robotics practical application success story yet. Which is why Harvard open-sourced its toolkit to give tinkerers everywhere a chance to come up with the best applications for the science.