Building a robot means utilizing skills from three distinct disciplines: mechanical engineering, electrical engineering, and programming. Combine those three, and that’s mechatronics. Development boards like Arduino have simplified the electrical engineering and programming side of things, but the mechanical design of a robot still takes some serious skill — particularly if the design is unusual. YouTuber Gear Down For What? built a robot thing that is definitely unusual, and it’s an interesting look at remotely-actuated joints.
He was inspired to build Richard 9000 after watching the Black Mirrorepisode “Metalhead,” which heavily features killer dog-like robots. He got to thinking about how a complex appendage could be actuated without adding a lot of bulk to the appendage itself. The solution he landed on was the same one that your own body uses to move your fingers: joints that are actuated remotely with a tensile cable like your tendons. That’s hardly a new concept in robotics, but his build is a really impressive execution because of the sheer complexity.
Richard 9000’s tentacle arm has a total of nine segments, including the stationary base. That means there are eight joints between them, and each joint is actuated with two fishing line cables. Those cables run through tubes to spools mounted on 16 servo motors. When the servos spin, they either add or remove tension on the cables to independently actuate the joints. From there, it was just a matter of programming the Arduino servo control to coordinate the movement of all the joints. The finished robot is certainly strange, but it’s also a fantastic illustration of the flexibility that remotely-actuated joints offer.