A Giant 3D-Printed Robotic Hand Fit for a Titan

Huge rideable mechs are a hallmarks of certain kinds of science-fiction — to the point where they have their own genre that is very popular in countries like Japan. But we rarely see mechs in real life, because they're wildly expensive to build and come with many engineering challenges. A large part of the cost comes down to all the custom fabrication that a mech would require. But maybe 3D-printing can bring that cost down and make mechs more approachable. Ivan Miranda wanted to find out and decided to test the idea by building a giant 3D-printed robotic hand fit for a titan.

Miranda started with the hand in order to prove the concept and determine if this idea is even remotely feasible. That doesn't, however, mean that this project was easy. The hand is absolutely massive and even a static model of this size would have been a serious undertaking. But this isn't static—it is fully articulated and motorized. It has as many joints as an actual human hand and each of those is independently controllable. That means 15 individual motors that all have to support a significant amount of weight and ideally a respectable payload.

Luckily, Miranda has several large-format 3D printers that he's built himself over the years. Those let him print the over-sized components as single parts, which most of us would have had to break up into smaller pieces. Most of those were rigid PLA, but the pads of the fingers and on the palm were flexible TPU.

A heavy duty servo motor actuates each joint and an Arduino Mega board controls all of those with PWM (pulse-width modulation). Most of those servos can produce 11kg-cm of torque, which is quite impressive. But the servos in the palm at the base of each finger are extra beefy at 25kg-cm of torque.

Even with all of that torque, this hand isn't particularly strong. It can move itself without any trouble, but would struggle to grasp anything heavy. The belts also stretch and skip under tension, but that is solvable with stronger belts.

We aren't sure if Miranda will build the rest of the mech to go with this hand, but we would sure love to see that.