A Walking Rover Destined Explore Your Fridge Door

It’s usually the simple ideas that sprout bigger ones, and this was the case when we saw [gzumwalt]’s single-motor walking robot crawling up a fridge door with magnets on its feet. (Video, embedded below.)

The walking mechanism consists of an inner foot and two outer feet, connected by three sets of rotating linkages, driven by a single geared motor. The feet move in a leapfrog motion, in small enough steps that the center of mass always stays inside the foot area, which keeps it from tipping over. Besides the previously mentioned ability to crawl around on a vertical magnetic surface, it’s also able to crawl over almost any obstacle shorter than its step length. A larger version should also be able to climb stairs.

As shown, this robot can only travel in a straight line, but this could be solved by adding a disc on the bottom of the inner foot to turn the robot when the outer feet are off the surface. Add some microswitch feelers and an Arduino, and it can autonomously explore your fridge without falling off. Maybe we’ll get around to building it ourselves, but be sure to drop us a tip if you beat us to it!

[gzumwalt] is a master of 3D printed devices like a rigid chain and a domino laying robot. The mechanism for this robot was inspired by one design from [thang010146]’s marvelous video library of mechanisms.

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Robot Gets Around On All Fours, Thanks To Many, Many Servos

As far as robots are concerned, wheels and tracks are great ways to get around when you’ve got serious work to do. However, if you want to build something that feels more animal than machine, building a walking ‘bot is the way to go. [Technovation] delivers a great example in the form of this quadruped design.

It’s a build executed in the modern style, taking full advantage of contemporary design tools and processes. The entire robot is built around twelve servo motors that provide rotation and translation to the robot’s joints. After importing the servo models into Fusion 360, [Technovation] set about building the rest of the body around them. An Arduino Uno runs the show, which addresses the many servos thanks to a Sensor Shield that has a multitude of useful outputs.

[Technovation] put a specific focus on durability and robustness during the design phase. The platform is intended as a test bed for various walking styles and gaits, and thus any hardware failures would be an unnecessary distraction from the project’s goals. The chassis is a great platform to learn on, and we expect to see further developments in future.

The eerily lifelike robots from Boston Dynamics may have set a high bar, but DIYers are still out there having a crack at building capable walking robots. Video after the break.

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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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Crawling PCB ‘Bot Is Flexible Where It Counts

20 years ago, PCB production was expensive and required a multitude of phone calls and emails to a fab with significant minimum order restrictions. Now, it’s cheap and accessible online, which in addition to curtailing the home etching market has created significant new possibilities for home projects. Now that flexible PCBs are also readily available, it’s possible to experiment with some cool concepts – and that’s precisely what [Carl] has been doing.

The aim is to build a walking robot that uses actuators made from flexible PCBs. The flexible PCB is printed with a coil, capable of generating a small magnetic field. This then interacts with a strong permanent magnet, causing the flexible PCB to move when energised.

Initial attempts with four actuators mounted to a 3D printed frame were unsuccessful, but [Carl] has persevered. With a focus on weight saving, the MK II prototype has shown some promise, gently twitching its way across a desk in testing. Future steps will involve building an untethered version. This will replace the 3D printed chassis with a standard fibreglass PCB acting as both control board and the main chassis to minimise weight, similar to PCB quadcopter designs we’ve seen in the past.

We can’t wait to see the next revision, and if you’ve been working on your own walking robots, make sure you let us know.

Hybrid Robot Walks, Transforms, And Takes Flight

[Project Malaikat] is a 3D printed hybrid bipedal walker and quadcopter robot, but there’s much more to it than just sticking some props and a flight controller to a biped and calling it a day. Not only is it a custom design capable of a careful but deliberate two-legged gait, but the props are tucked away and deployed on command via some impressive-looking linkages that allow it to transform from walking mode to flying mode.

Creator [tang woonthai] has the 3D models available for download (.rar file) and the video descriptions on YouTube contain a bill of materials, but beyond that there doesn’t seem to be much other information available about [Malaikat]. The creator does urge care to be taken should anyone use the design, because while the robot may be small, it does essentially have spinning blades for hands.

Embedded below are videos that show off the robot’s moves, as well as a short flight test demonstrating that while control was somewhat lacking during the test, the robot is definitely more than capable of actual flight.

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Wave Goodbye To Honda Asimo, A Robot That Would Wave Back

Fans of technology will recall a number of years when Honda’s humanoid robot Asimo seemed to be everywhere. In addition to its day job in a research lab, Asimo had a public relations side gig showing everyone that Honda is about more than cars and motorcycles. From trade shows to television programs, even amusement parks and concert halls, Asimo worked a busy publicity schedule. Now a retirement party may be in order, since the research project has reportedly been halted.

Asimo’s activity has tapered off in recent years so this is not a huge surprise. Honda’s official Asimo site itself hasn’t been updated in over a year. Recent humanoid robots in media are more likely to be in context of events like DARPA Robotics Challenge or from companies like Boston Dynamics. Plus the required technology has become accessible enough for us to build our own two-legged robots. So its torch has been passed on, but Asimo would be remembered as the robot who pioneered a lot of thinking into how humanoid robots would interact with flesh and blood humans. It was one of the first robots who could recognize human waving as a gesture, and wave back in return.

Many concepts developed from Asimo will live on as Honda’s research team shift focus to less humanoid form factors. We can see Honda’s new ambitions in their concept video released during CES 2018 (embedded below.) These robots are still designed to live and work alongside people, but now they are specialized to different domains and they travel on wheels. Which is actually a step closer to the Jetsons’ future, because Rosie rolls on wheels!

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[James Bruton] Is Making A Dog: OpenDog Project

There was a time when a two-legged walking robot was the thing to make. But after seeing years of Boston Dynamic’s amazing four-legged one’s, more DIYers are switching to quadrupeds. Now we can add master DIY robot builder [James Bruton] to the list with his openDog project. What’s exciting here is that with [James’] extensive robot-building background, this is more like starting the challenge from the middle rather than the beginning and we should see exciting results sooner rather than later.

James' motor and ball screws
James’ motor and ball screws

Thus far [James] has gone through the planning stage, having iterated through a few versions using Fusion 360, and he’s now purchased the parts. It’s going to be about the same size as Boston Robotic’s SpotMini and uses three motors for each leg. He considered going with planetary gearboxes on the motors but experienced a certain amount of play, or backlash, with them in his BB-9E project so this time he’s going with ball screws as he did with his exoskeleton. (Did we mention his extensive background?)

Each leg is actually made up of an upper and lower leg, which means his processing is going to have to include some inverse kinematics. That’s where the code decides where it wants the foot to go and then has to compute backwards from there how to angle the legs to achieve that. Again drawing from experience when he’s done it the hard way in the past, this time he’s designed the leg geometry to make those calculations easy. Having written up some code to do the calculations, he’s compared the computed angles with the measurements he gets from positioning the legs in Fusion 360 and found that his code is right on. We’re excited by what we’ve seen so far and bet it’ll be standing and walking in no time. Check out his progress in the video below.

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