Episode 39: Not all robots are hard and made of metal…

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Picture a robot. Seriously, close your eyes for 30 seconds and picture a robot in your head. Ok, most of you probably didn’t do it but if you had, my guess is that you would have pictured something very boxy, perhaps with pincher hands, quite awkward in its movements and perhaps with a weird robotic voice pre-Siri era. Or maybe something R2-D2 like. That’s definitely what comes to mind for me. Well, robots don’t all look like that. In fact, some robots aren’t hard and made of metal at all. Some are soft and pliable, and they’re the kind that Nick Bira studies.

Nick is a 3rd year PhD student in the Department of Robotics working with Dr. Joseph Davidson. When asked to summarize his research into just a few words, Nick answered that he works on magnetism and soft robotics. What is soft robotics and why would we want a soft robot you may ask (I know I certainly did)? Well, soft robotics is exactly what the phrase implies – they’re robots that are soft, absolutely no hard parts (or very few) to them. Why would we want a soft robot? Well, imagine if you have a small space that you need a robot to fit through, like a small hole. A soft robot can mold into the shape that you need it to. Alternatively, soft robots are becoming more and more needed and used in medical robotics. After all, you don’t want some hard, klanky thing poking around inside of you and possibly causing damage. You’d much rather have something that’s soft, gentle, compliant and non-damaging. Another example is in instances of human-robot interactions and increasing the safety of such interactions. A big, metallic, hard robot on an assembly line could easily spin and injure a human. But a robot with arms designed like tentacles that are floppy and soft, will perhaps push you over and bruise you, but not lead to serious damage.

The utility of soft robotics is manifold. So why aren’t they used more or why haven’t you heard much of them before? Well, the challenge is how to keep the utility of a hard robot while making it soft and, by proxy, safe. In part, this is down to how the robot and its movements are controlled. Most soft robots to date are controlled by or pneumatics or hydraulics (using air or liquid pressure). The downside of these is that the soft robot has to be accompanied by bulky hard components, such as a pumps, electrical sources, batteries, or air tanks. So even though you may have this super soft, compliant robot, it comes with large apparatuses that are not soft. Kind of counter-intuitive. 

This is where the other half of Nick’s research phrase comes in – magnetism. Magnetism has very limited usage as a tool in soft robotics and Nick thinks it should be applied more. If you’re having a hard time picturing how a magnet could be used in soft robotics, then visualize this example Nick gave us. It could be used in a pincher – instead of using air pressure in inflate the pincers to open and close, you could have the fingers of the pincer be made out of stretch magnetic material that closes when exposed to a magnetic field. It seems pretty simple right? And yet, it doesn’t yet exist in soft robotics. This is why Nick is exploring this possibility because he believes ideas like this could be useful building blocks, and once we have them, we can build more complicated things. 

Now, you may be thinking, hang on, magnets are hard, I thought this was all about soft robotics? Good thought – here’s how Nick is planning to work around that. Nick is embedding iron particles, which are magnetically soft, into silicone rubber, which is a soft elastic material, to make a material that is soft and hyper elastic and when brought close to an ordinary magnet, will stick to it. However, this is only step 1. Nick is interested in creating magnetic fields within the robot rather than it only working if there is a big, hard magnet nearby. One core goal of soft robotics is to have them function on their own without needing some hard object nearby to ‘support’ it. He is still in the development and testing stages of this material, but Nick does have an application in mind. He wants to make a magneto-rheological fluid (MRF) valve that can be used in soft robots. Rather than have this valve open and shut with air pressure (which would require air tanks to accompany the robot), Nick wants the valve to open and close through a magnetic field generated by the elastic, soft magnetic material. This way everything would be compact, stretchy, and wouldn’t require any additional bulky parts.