Using Multiple Quadcopters To Efficiently Lift Loads Together

Much like calling over a buddy or two to help with moving a large piece of furniture and pivot it up a narrow flight of stairs, so too can quadcopters increase their carrying capacity through the power of friendship and cooperation. However, unless you want to do a lot of yelling at your mates about when to pivot and lift, you’d better make sure that your coordination is up to snuff. The same is true with quadcopters, where creating an efficient coordination algorithm for sharing a load is far from easy and usually leads to fairly slow and clumsy maneuvering.

Simplified overview of the motion planner by Sihao Sun et al.
Simplified overview of the motion planner by Sihao Sun et al.

Recently. researchers at the Technical University of Delft came up with what appears to be a quite efficient algorithm for this purpose. In the demonstration video below, it’s easy to see how the quadcopters make short work of even convoluted obstacles while keeping themselves and their mates from getting tangled.

The research by [Sihao Sun] et al. appears in Science Robotics (preprint), in which they detail their trajectory-based framework and its kinodynamic motion planner. In short, this planner considers the whole-body dynamics of the load, the cables, and the quadcopters. An onboard controller for each quadcopter is responsible for translating the higher-level commands into specific changes to its rotor speeds and orientation.

Along with tests of its robustness to various environmental factors, such as wind, the researchers experimented with how many simultaneous quadcopters could work together with their available computing capacity. The answer, so far, is nine units, though they think that the implementation can be further optimized.

Of course, sometimes you just want to watch synchronized drones.

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If IRobot Falls, Hackers Are Ready To Wrangle Roombas

Things are not looking good for iRobot. Although their robotic Roomba vacuums are basically a household name, the company has been faltering financially for some time now. In 2024 there was hope of a buyout by Amazon, who were presumably keen to pull the bots into their Alexa ecosystem, but that has since fallen through. Now, by the company’s own estimates, bankruptcy is a very real possibility by the end of the year.

Hackaday isn’t a financial blog, so we won’t get into how and why iRobot has ended up here,  although we can guess that intense competition in the market probably had something to do with it. We’re far more interested in what happens when those millions of domesticated robots start getting an error message when they try to call home to the mothership.

We’ve seen this scenario play out many times before — a startup goes belly up, and all the sudden you can’t upload new songs to some weirdo kid’s media player, or the gadget in your fridge stops telling you how old your eggs are. (No, seriously.) But the scale here is unprecedented. If iRobot collapses, we may be looking at one of the largest and most impactful smart-gadget screw overs of all time.

Luckily, we aren’t quite there yet. There’s still time to weigh options, and critically, perform the kind of research and reverse engineering necessary to make sure the community can keep the world’s Roombas chugging along even if the worst happens.

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Dual-Arm Mobile Bot Built On IKEA Cart Costs Hundreds, Not Thousands

There are many incredible open-source robotic arm projects out there, but there’s a dearth of affordable, stable, and mobile robotic platforms with arms. That’s where XLeRobot comes in. It builds on the fantastic LeRobot framework to make a unit that can be trained for autonomous tasks via machine learning, as well as operated remotely.

XLeRobot, designed by [Vector Wang], has a pretty clever design that makes optimal use of easy to obtain parts. In addition to the mostly 3D-printed hardware, it uses an IKEA cart with stacked bin-like shelves as its main frame.

The top bin holds dual arms and a central stalk with a “head”. There’s still room left in that top bin, a handy feature that gives the robot a place to stow or carry objects.

The bottom of the cart gets the three-wheeled motion unit. Three omnidirectional wheels provide a stable base while also allowing the robot to propel itself in any direction and turn on a dime. The motion unit bolts to the bottom, but because the IKEA cart’s shelf bottoms are a metal mesh, no drilling is required.

It’s all very tidy, and results in a mobile robotics platform that is cheap enough for most hobbyists to afford, while being big enough to navigate indoor environments and do useful tasks.

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Does 3D-Printed Foam Make Good Custom Tires?

Wouldn’t it be nice to 3D print an entire custom tire for small robots? It sure would, so [Angus] of [Maker’s Muse] decided to investigate whether nifty new filaments like expanding TPU offer anything new in this area. He did more than just print out a variety of smooth tires; he tested each with a motorized platform attached to a load cell, driving on a dusty sheet of MDF to simulate the average shop floor, or ant weight combat robot arena.

Why bother making your own wheels? As [Angus] points out, when one is designing their own robots from scratch, it’s actually quite difficult to find something off the shelf that is just the right size. And even if one does find a wheel that is just right, there’s still the matter of fitting it to the shaft. Things would be so much easier if one could simply 3D print both wheel and tire in a material that performs well.

Like TPU, but squishier.

Here’s what he found: Siraya Tech’s TPU air filament (about 70A on the Shore hardness scale) performed the best. This is TPU plus a heat-activated additive that foams up during extrusion, resulting in a flexible print that looks and feels more like foam than usual TPU. It makes a promising tire that performs as well as it looks. Another expanding filament, PEBA air (also from Siraya Tech) didn’t look or perform as well, but was roughly in the same ballpark.

Both performed better than the classic DIY options of 3D-printed plain TPU, or laser-cut EVA foam. It’s certainly a lot less work than casting custom tires.

What about adding a tread pattern? [Angus] gave it a try. Perhaps unsurprisingly, a knobby tire has worse traction compared to a smooth tire on smooth MDF. But sometimes treads are appropriate, and as [Angus] points out, if one is 3D printing tires then adding treads comes at essentially zero cost. That’s a powerful ability.

Even if you are not interested in custom wheels, that foaming TPU filament looks pretty nifty. See for yourself in the video, embedded just below. If you find yourself finding a good use for it, be sure to drop us a tip!

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Pi Zero Powers A Little Indoor Rover

Not every robot has to be big. Sometimes, you can build something fun that’s better sized for exploring your tabletop rather than the wastelands of Mars. To that end, [philosiraptor] built the diminutive PITANK rover.

As you might guess from the name, the rover is based on the Raspberry Pi Zero 2. It uses the GPIO pins to output PWM signals, commanding a pair of servos that drive the tracks on either side of the ‘bot. The drivetrain and chassis are made from 3D-printed components. Controlling the robot is handled via a web interface, which [philosiraptor] coded in C# to be as responsive as possible. So you can see where you’re driving, the ‘bot is also kitted out with a camera to provide a live video feed.

Given its low ground clearance and diminutive size, you’re not going to go on big outdoor adventures with PITANK. However, if you wish to explore a nice flat indoor environment, its simple tracked drivetrain should do nicely. We’ve featured a great many rovers over the years; if you’ve got a particularly special one, don’t hesitate to notify the tipsline!

Building A Rubik’s Cube That Solves Itself

If you’re really good, it’s possible to solve a Rubik’s Cube in under 10 seconds. For the rest of us, though, it can be an exceedingly tedious task. For that reason, you might like a Rubik’s Cube that can solve itself, like the one [zeroshot] is trying to build.

What [zeroshot] built is essentially a very small robotic platform inside the center section of an existing Rubik’s Cube. It uses five gear motors that are assembled into the cube’s core, which have enough torque to rotate the individual faces quite easily. While six motors would allow more efficient solves in fewer moves, it was easier to fit just five motors inside the cube, and they’d still get the job done. The motors are controlled by an ESP32, hooked up to a bank of DRV8833 motor drivers. For now, the cube is still a work in progress. While the core can move the faces, [zeroshot] is trying to figure out how to best tackle the problem of feedback in the limited space available. After all, the ESP32 needs to know where the faces are if it’s to make the right moves to reach a solved state. Soldering wires between individual modules can be quite space inefficient; this is one build that might benefit from being integrated onto a single tiny PCB.

We’re used to seeing robots that grab a Rubik’s cube and solve it for you; we haven’t seen a lot of cubes that solve themselves. Regardless, this feat has been achieved before. Video after the break.

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Record-Breaking Robots At Guinness World Records

If you ever wanted to win a bar bet about a world record, you probably know about the Guinness book for World Records. Did you know, though, that there are some robots in that book? Guinness pointed some out in a recent post.

Ever wonder about the longest table-tennis rally with a robot or the fastest robotic cube solver? No need to wonder anymore.

Our favorite was the fastest robot to solve a puzzle cube. This robot solved the Rubik’s Cube in 103 milliseconds! Don’t blink or you’ll miss it in the video embedded. Of course, the real kudos go to the team that created the robot: [Matthew Patrohay], [Junpei Ota], [Aden Hurd], and [Alex Berta].

Another favorite was the smallest humanoid robot. In order to win this record, the robot must be able to move its shoulders, elbows, knees, and hips just like a human. It also has to be able to walk on two feet. This tiny little guy meets the requirements and stands only 57.6 mm (2.26 in) tall! Created by [Tatsuhiko Mitsuya] in April 2024, this robot can be controlled via Bluetooth.

We’ve seen entries in this category before — check them out in Almost Breaking The World Record For The Tiniest Humanoid Robot, But Not Quite.

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