Spherical Quadruped Arduino Robot

[Greg06] started learning electronics the same way most of us did: buy a few kits, read a few tutorials, and try your hardest to put a few things together. Sound familiar? After a while, you noticed your skills started increasing, and your comfort level with different projects improved as well. Eventually, you try your hand at making your own custom projects and publishing your own tutorials.

Few are lucky to have a first-project as elaborate as [Greg06’s] quadruped robot. We don’t know about you, but for some of us, we were satisfied with blinking two LEDs instead of just one.

[Greg06’s] robot has a quadruped based, housed within a 3D printed spherical body. The legs are retractable and are actuated by tiny servo motors inside the body. [Greg06] even included an ultrasonic distance sensor for the obstacle avoidance mechanism. Honestly, if it weren’t for the ultrasonic distance sensor protruding from the spherical body, you might think that the entire robot was just a little Wiffle ball. This reminds us of another design we’ve seen before.

If that weren’t enough, the spherical head can rotate, widening the range of the ultrasonic distance sensor and obstacle avoidance mechanism. This is accomplished by attaching another servo motor to the head.

Pretty neat design if you ask us. Definitely one of the coolest quadrupeds we’ve seen.

Compliant Quadruped Legs Using Servos

Walking robots that move smoothly are tricky to build and usually involve some sort of compliant leg mechanism — a robot limb that can rebound like natural physiology for much better movement than what a stiff machine can accomplish. In his everlasting quest to build a real working robot dog, [James Bruton] is working on an affordable and accessible Mini Robot Dog, starting with the compliant leg mechanism.

The 3D printed leg mechanism has two joints (hip and knee), with an RC servo to drive each. To make the joints compliant, both are spring-loaded to absorb external forces, and the deflection is sensed by a hall effect sensor with moving magnets on each side. Using the inputs from the hall effect sensor, the servo can follow the deflection and return to its original position smoothly after the force dissipates. This is a simple technique but it shows a lot of promise. See the video after the break.

A project can sometimes develop a life of its own, or in the case of [James]’s OpenDog, spawn experimentally evolving offspring. This is number four, and it’s designed  to be a platform for learning how to make a quadruped walk properly, and to be simple and cheap enough for others to build. We’re looking forward to seeing how it turns out.

If you missed it, also check out this robot’s weird sibling, self-balancing Sonic.

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Quadruped Robot Disguises Itself As A Ball

When the Skynet baseball bot swarms attack, we’ll be throwing [Carl Bugeja] some dirty looks for getting them started. He’s been working on 4B, a little quadruped robot that can transform itself into a sphere almost perfectly.

Before [Carl] was distracted by the wonders of PCB actuators more than a year ago, he started working on this little guy. He finally found some time to get it moving on its own, and the preliminary results look promising to say the least. Inside the 6 cm sphere is a total of 12 servos, 3 for each leg. All of the mechanical parts were 3D printed in nylon on an SLS machine, and the custom PCB has a BLE microcontroller module, an IMU and IR proximity sensors onboard. Everything is open source with all the files available on the Hackaday.io project page.

The microcontroller runs a full inverse kinematic model, so only the desired tip and base coordinate for each leg is input and the servo angles are automatically calculated. Ultimately [Carl] aims to have the robot both walking and rolling controllably. So far he’s achieved some degree of success in both, but it still needs some work (see the videos below. We’re eager to see what the future holds for this delightfully creepy bot.

Walking robots are always an interesting challenge. For more of our future overlords, check out this adorable little cat and this truly terrifying strandbeest.

Amazing Open Source Quadruped Capable Of Dynamic Motion

The more we read about [Josh Pieper]’s quadruped, the mjbots quad A0, the more blown away we are by his year of progress on the design. Each part of the robot deserves its own article: from the heavily modified brushless motors (with custom planetary gears) to the custom motor driver designed just for this project.

[Josh], realized early on that the off-the-shelf components like an ODrive just weren’t going to cut it for his application. So he designed his own board, took it through four revisions, and even did thermal and cycle testing on it. He ended up with the compact moteus board. It can pump out 400 Watts of peak power while its 3Mbit control protocol leaves plenty of bandwidth for real time dynamic control.

The motors and gearboxes are also impressive. It took thorough experimenting and taking inspiration from other projects  before he arrived at a 8108 quad copter motor modified and upgraded so heavily its own mother wouldn’t recognize it. This is all packed into a leg unit with three degrees of freedom that puts even the fanciest servo based quadruped to shame.

Finally it’s all packed into a neat four-legged robot frame with batteries and a Pi. You can get a video summary of the robot here or after the break, and we recommend reading his blog for some more images and details.

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Watch The Snappy, Insect-like Moves Of This DIY Quadruped Robot

Some legged robots end up moving with ponderous deliberation, or wavering in unstable-looking jerks. A few unfortunates manage to do both at once. [MusaW]’s 3D Printed Quadruped Robot, on the other hand, moves in rapid motions that manage to look sharp and insect-like instead of unstable. Based on an earlier design he made for a 3D printable quadruped frame, [MusaW] has now released this step-by-step guide for building your own version. All that’s needed is the STL files and roughly $50 in parts from the usual Chinese resellers to have the makings of a great weekend project.

The robot uses twelve SG90 servos and an Arduino nano with a servo driver board to control them all, but there’s one additional feature: Wi-Fi control is provided thanks to a Wemos D1 Mini (which uses an ESP-8266EX) acting as a wireless access point to serve up a simple web interface through which the robot can be controlled with any web browser.

Embedded below is a brief video. The first half is assembly, and the second half demonstrates the robot’s fast, sharp movements.

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Quadruped Robot Can Crawl Under Cars And Jump-Kick-Open Doors

The wheel is a revolutionary invention — as they say — but going back to basics sometimes opens new pathways. Robots that traverse terrain on legs are on the rise, most notably the Boston Dynamics Big Dog series of robots — and [Ghost Robotics]’ Minitaur quadruped aims to keep pace.

One of [Ghost Robotics] founders, [Gavin Knneally] states that co-ordination is one of the main problems to overcome when developing quadruped robots; being designed to clamber across especially harsh terrain, Minitaur’s staccato steps carry it up steep hills, stairs, across ice, and more. Its legs also allow it to adjust its height — the video shows it trot up to a car, hunker down, then begin to waddle underneath with ease.

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Adorable Quadruped Robot Hops And Walks

The ESP8266 is finding its way into all sorts of projects these days. It’s a capable little device, to be sure, but we’d have to say that finding it running a quadruped robot that can hop and run was a little unexpected. And to have it show up in such an adorable design was pretty cool too.

From the looks of [Javier Isabel]’s build log, he put a lot of thought into [Kame]. All the body parts and linkages are 3D printed from PLA, with the nice touch of adding a contrasting color. The legs are powered by eight high-speed Turnigy servos, and good quality bearings are used in the linkages. A NodeMCU runs the show with custom oscillator algorithms that control the various gaits, including the hopping motion. The BOM even lists “Adhesive 12mm diameter eyes” – perhaps that’s some sort of slang for the more technically correct “googly eyes.”

Built primarily as a test platform for studying different gaits, there doesn’t seem to be much in the way of sensors in [Kame]’s current incarnation. But with an ESP8266 under the hood, the possibilities for autonomous operation are good. We look forward to seeing where this project goes next. And we kid about the cuteness factor, but never doubt the power of an attractive design to get the creative juices flowing.

We’ve covered a lot of quadruped robots before, and a lot of them seem to trend toward the cute end of the spectrum. Check out this baby-quad that’s learning to walk or this quad that thinks it’s a puppy.

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