For all their joking about “reinventing the wheel”, the team behind Ourobot made a very cool robot (German, automatic translation here). The team, at the University of Applied Sciences in “Bielefeld, Germany“, built their wheel out of twelve segments, each with its own servo motor, a 3D-printed case, and a pressure sensor mounted on the outside of the wheel. The latter, plus some clever programming, allows the robot wheel to vary its circular gate and climb up over obstacles automatically.
There are a bunch of interesting constraints in designing the control for this bot. The tracks on the ground, naturally, have to adjust their relative angles so that they lie each flat on the surface, even if that surface isn’t itself flat or level. The segments in the air are unconstrained, but the sum of all the servos’ interior angles has to add up to 1800 degrees, and these angles control where its center of gravity is.
A robot to explore the unknown and automate tomorrow’s tasks and the ones after them needs to be extremely versatile. Ideally, it was capable of being any size, any shape, and any functionality, shapeless like water, flexible and smart. For his Hackaday Prize entry, [Alberto] is building such a modular, self-reconfiguring robot: Dtto.
To achieve the highest possible reconfigurability, [Alberto’s] robot is designed to be the building block of a larger, mechanical organism. Inspired by the similar MTRAN III, individual robots feature two actuated hinges that give them flexibility and the ability to move on their own. A coupling mechanism on both ends of the robot allows the little crawlers to self-assemble in various configurations and carry out complex tasks together. They can chain together to form a snake, turn into a wheel and even become four (or more) legged walkers. With six coupling faces on each robot, that allow for connections in four orientations, virtually any topology is possible.
Each robot contains two strong servos for the hinges and three smaller ones for the coupling mechanism. Alignment magnets help the robots to index against each other before a latch locks them in place. The clever mechanism doubles as an ejector, so connections can be undone against the force of the alignment magnets. Most of the electronics, including an Arduino Nano, a Bluetooth and a NRF24L01+ module, are densely mounted inside one end of the robot, while the other end can be used to add additional features, such as a camera module, an accelerometer and more. The following video shows four Dtto robots in a snake configuration crawling through a tube.
Here’s an oldie but a goodie: [Eiki], [Mark], and [Sheraz] built a pipe crawling robot for their senior engineering project at Florida Atlantic University way back in 2004. Despite being a rather old build, its aged well and still demonstrates the clever ways the guys overcame some engineering obstacles.
The original plan for the pipe crawler was to mount three spring-loaded wheels 120° apart at the fore and aft of each robot section. Six independent wheels for each section of the robot is overly complex, and too much for a single operator to control; the team moved on to a ‘screw drive’ system where each wheel is canted forward a few degrees. This drive system propels the snakebot along by simply spinning, although it does bring in a few challenges all its own.
The robot had separate sections consisting to house a motor, camera, and electronics, so a way to pass wires through a rotating shaft was needed. This came in the form of a few pairs of incredibly small ball bearings around a hollow shaft. After the mechanical portion of the build was finished, the team moved on to the electronic part where an IMU was built out of three small gyroscope sensors mounted perpendicularly to each other.
Sadly, there are no videos of the inside of a sewage pipe from the pipe crawler’s point of view, but YouTube wasn’t launched until a year after this project was finished.
[Husstech] wrote in to share his Snake Bot with us. Initially inspired by this post about SickSack, a snake bot, he set out to build his own version. While the concept and even the design aren’t particularly new or groundbreaking, he is very thorough in his documentation. Since this was a project for school, the PDF of his project includes research, schematics, cost breakdowns, and results. We really like the camera and head design, it looks very insect like. You can see a video of the final version being shown off after the break, or you can see an earlier version that is decidedly more phallic.
[Lars] sent in this sweet snake robot that he and [Aske] built for the DTU Robocup. I’ve seen snake bots before, but I like the concept and the clean electronic design. They used a single AtMega32 controller to generate PWM signals for each of the eight servos, and used a very interesting DC-DC buck converter that’s capable of delivering 16 amps.
For the curious, the bot won the best design and effects award at the competition.