A DIY Tentacle Bot Right Out of Doctor Octopus' Lab
For a recent e14 Presents project, DJ Harrigan decided to create his own continuum robot.
As e14 Presents' DJ Harrigan notes in his project video, nature doesn’t use wheels (unless you count a very weird little flea with a geared leg mechanism called a “planthopper”). So while robots generally attempt to mimic human or animal behavior, perhaps the wheels that are used internally and externally on such devices aren’t the optimum solution.
One alternative is a continuum robot, also known as a robot tentacle. Here, Harrigan created a fairly simple implementation capable of gripping a screwdriver or other item to twist it in different directions.
The heart of the build is a series of circular plates, along with 3D-printed adapters and little universal joints. These let the segments pitch and yaw in different directions, while preventing it from twisting and loosing alignment. To cause it to move, he’s using a series of Kevlar strings, pulled and released by a pair of powerful servo motors via pulley wheels. After redesigning the wheels to keep the strings from sliding, he’s able to move the end of this 10-disk tentacle under control of an Arduino Mega, running a potentiometer knob/servo demo sketch.
Harrigan added a servo gripper on the end as well, allowing it to hold a screwdriver, or whatever other small implement he has in mind in the future. As shown, the device mostly flexes on the end, though with a bit of modification to enable it to roll up more of the “tendons” it could theoretically move much further. Despite having seen these types of robots in action, actually constructing one certainly provides a better understanding of how they behave in real life!
