Mini Cheetah Clone Teardown, By None Other Than Original Designer

December 19, 2022 by Donald Papp 21 Comments

[Ben Katz] designed the original MIT Mini Cheetah robot, which easily captured attention and imagination with its decidedly un-robotic movements and backflips. Not long after [Ben]’s masters thesis went online, clones of the actuators started to show up at overseas sellers, and a few months after that, clones of the whole robot. [Ben] recently had the opportunity to disassemble just such a clone by Dogotix and see what was inside.

Amusingly, one of the first things he noticed is that the “feet” are still just off-the-shelf squash balls, same as his original mini cheetah design. As for the rest of the leg, inside is a belt that goes past some tensioners, connecting the knee joint to an actuator in the shoulder.

As one may expect, these parts are subject to a fair bit of stress, so they have to be sturdy. This design allows for slender yet strong legs without putting an actuator in the knee joint, and you may recall we’ve seen a similar robot gain the ability to stand with the addition of a rigid brace.

It’s interesting to read [Ben]’s thoughts as he disassembles and photographs the unit, and you’ll have to read his post to catch them all. But in the meantime, why not take a moment to see how a neighbor’s curious sheep react to the robot in the video embedded below? The robot botches a backflip due to a low battery, but the sheep seem suitably impressed anyway.

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Robot Gets A Life-Sized Pokemon Costume For Halloween

November 12, 2022 by Lewin Day 3 Comments

Quadruped robots are everywhere now that companies like Boston Dynamics are shipping smaller models in big numbers. [Dave’s Armoury] had one such robot, and wanted to give it a Pokemon Halloween costume. Thus, the robot dog got a Jolteon costume that truly looks fantastic. (Video, embedded below.)

You would think that covering a quadruped robot in foam would ruin it, but somehow it didn’t stop it moving too badly at all.

The robot in question is a Unitree Go1, which [Dave] had on loan from InDro robotics. Thus, the costume couldn’t damage or majorly alter the robot in any way. Jolteon was chosen from the original 150 Pokemon as it had the right proportions to suit the robot, and its electric theme fitted [Dave’s] YouTube channel.

A 3D model of Jolteon was sourced online and modified to create a printable head for the robot application. Two 3D printers and 200 hours of printing time later, and [Dave] had all the parts he needed. Plenty of CA glue was used to join all the parts together with some finishing required to make sure seams and edges didn’t spoil the finish too much. Wood filler and spray paint were used to get the costume looking just like the real Pokemon. Continue reading “Robot Gets A Life-Sized Pokemon Costume For Halloween” →

Hackaday Links: August 14, 2022

August 14, 2022 by Dan Maloney 14 Comments

What’s this? News about robot dogs comes out, and there’s no video of the bots busting a move on the dance floor? Nope — it looks like quadruped robots are finally going to work for real as “ground drones” are being deployed to patrol Cape Canaveral. Rather than the familiar and friendly Boston Dynamics “Big Dog” robot, the US Space Force went with Ghost Robotics Vision 60 Q-UGVs, or “quadruped unmanned ground vehicles.” The bots share the same basic layout as Big Dog but have a decidedly more robust appearance, and are somehow more sinister. The dogs are IP67-rated for all-weather use, and will be deployed for “damage assessments and patrols,” whatever that means. Although since this is the same dog that has had a gun mounted to it, we’d be careful not to stray too far from the tours at Kennedy Space Center.

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Moteus Open Source BLDC Controller Gets Major Upgrade

July 4, 2022 by Chris Lott 6 Comments

[Josh Pieper] of mjbots Robotic Systems just released a major revision to his moteus open sourced brushless DC (BLDC) electric motor controller. The update adds a flexible I/O subsystem which significantly expands the kinds of feedback encoders and peripherals the controller can accept. In the video below the break, [Josh] walks through eleven different example configurations. If you prefer, these examples are also presented in article form on his blog.

The moteus controller originally came about when [Josh] was developing the quad A0, an open source dynamic quadruped robot, along the lines of the MIT Mini Cheetah or Boston Dynamics robotic dogs, and wasn’t satisfied that existing controllers could do the trick. It’s a compact 50 mm square board based on an STM32G4, has an integrated magnetic encoder, and accepts external sensor connections. Interfacing with the board is via CAN-FD using a register-based scheme. A Python GUI tool provides name-based register access via a logical tree structure as well as real-time telemetry plotting capabilities for diagnostic and configuration tasks.

If you are using BLDC motors in your projects, definitely check this out. Even if you’re not using a moteus controller, [Josh]’s demonstrations of the various encoder feedback technologies is very interesting and educational. The entire project is open source, and both the hardware and software design files can be found on the project’s GitHub repository. For some users, this may be a major factor, considering that the latest ODrive BLDC controller offering has become closed source.

We wrote about the mjbots quad A0 in 2019, and you can follow the moteus project over on Hackaday.io. We also found this interesting video by [Skyentific] comparing three popular open source BLCD controllers including the moteus (second video below the break). There’s also the SimpleFOC project we covered last year if you want to dig in and learn more about field-oriented control of BLDC motors. Thanks to [Androiddrew] for the tip.

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PicoCat, printed in yellow filament, looking at you with its ultrasonic sensor eyes

Build Your Own Cat – Some Assembly Required

April 18, 2022 by Arya Voronova 4 Comments

Robotic pets are sci-fi material, and [Kevin McAleer] from [Kev’s Robots] is moving us all ever so closer towards a brighter, happier, more robotic future. One of his latest robot builds, PicoCat, is a robot cat with servo-driven paws. It follows in the footsteps of the OpenCat project made by Dr. Rongzhong Li back in 2016, and we’re always happy seeing someone pick up where another hacker left off. [Kevin] took heavy inspiration from the OpenCat design – rebuilding it with hardware more friendly and accessible for makers today.

Projects like these, involving data processing and calculations to get the servos moving just right, stand to benefit from the computing power of recently released RP2040 MCU. As such, the Pimoroni Servo 2040 board is a crucial component of this build, being both the brains of the project and also a PIO-boosted driver for the eleven servos helping this robot come alive. This cat’s eyes are an ultrasonic sensor, and you can add a whole lot more sensors for any robotic intention of yours. Don’t expect this kitty to jump one meter high or scratch your favourite couch to death just yet, but there’s already a lot of potential, especially coupled with a small speaker.

Does this robotic cat interest you, whether it’d be due to your sci-fi propensity or a cat hair allergy? You’re in luck, because [Kevin] is keeping things firmly in the “open-source everything” realm. MicroPython code is stored in a GitHub repo, STLs are in a .zip linked on the page, and there’s plenty of renders to never leave you confused on what goes where. With all these resources, you can source the servos and the boards, fire up your 3D printer and sit down to assemble your own PicoCat. But not just that, [Kevin] also recorded three whole streams with insights, giving us over four hours of how-it-came-to-be video material for us to learn from. First, two streams of him designing the PicoCat in Fusion360, and then, him talking about the way he creates unit tests in MicroPython to improve his robots’ reliability and significantly reduce the amount of bugs cropping up.

This is not the last we will hear from [Kevin]’s robot-filled workshop, and previously, we’ve covered his Cray-1-shaped Pi Zero cluster system and a Raspberry Pi theremin, both as open and reproducible as this kitty! As you assemble yourself a PicoCat, or perhaps a Stanford Pupper or any of the other lovely quadru-pets we’ve previously featured, you might wonder how to properly move the servos, and we’ve covered a project that teaches you specifically that.

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2022 Sci-Fi Contest: Motorized AT-AT Walker Gets Around With Servos

April 15, 2022 by Lewin Day 6 Comments

The AT-AT Walker was one of the more fearsome weapons of the Star Wars universe, even if it was incredibly slow and vulnerable to getting tangled up in Rebel tow cables. However, you can build your own small-scale example using servos for propulsion, as [Luke J. Barker] ably demonstrates.

Taking off the outer shell reveals the servo motors driving the leg linkages.

The build is a remix of the motorized AT-AT from [LtDan] on Thingiverse, originally powered by a 90 rpm DC gearmotor. [Luke] remixed the design, setting it up to be driven by eight servomotors instead. They’re controlled from a SparkFun RedBoard Edge, an Arduino-compatible microcontroller board that fits rather neatly inside the AT-AT shell.

Programmed with a simple sine-wave walk cycle, the AT-AT ambles along in a ponderous manner. It’s altogether very much like the ~~real~~ fictitious thing, albeit without the scorching sizzle of blaster fire ringing out across a frozen plain.

Quadruped vehicles never really caught on for military use, but that’s not to say nobody ever tried. Video after the break.

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Classic Chat: Arko Takes Us Inside NASA’s Legendary JPL

February 25, 2022 by Tom Nardi 4 Comments

Started by graduate students from the California Institute of Technology in the late 1930s, the Jet Propulsion Laboratory (JPL) was instrumental in the development of early rocket technology in the United States. After being tasked by the Army to analyze the German V2 in 1943, the JPL team expanded from focusing purely on propulsion systems to study and improve upon the myriad of technologies required for spaceflight. Officially part of NASA since December of 1958, JPL’s cutting edge research continues to be integral to the human and robotic exploration of space.

For longtime friend of Hackaday Ara “Arko” Kourchians, getting a job JPL as a Robotics Electrical Engineer was a dream come true. Which probably explains why he applied more than a dozen times before finally getting the call to join the team. He stopped by the Hack Chat back in August of 2019 to talk about what it’s like to be part of such an iconic organization, reminisce about some of his favorite projects, and reflect on the lessons he’s learned along the way.

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