Legged Robots Put On Wheels And Skate Away

December 26, 2020 by Roger Cheng 6 Comments

We don’t know how much time passed between the invention of the wheel and someone putting wheels on their feet, but we expect that was a great moment of discovery: combining the ability to roll off at speed and our leg’s ability to quickly adapt to changing terrain. Now that we have a wide assortment of recreational wheeled footwear, what’s next? How about teaching robots to skate, too? An IEEE Spectrum interview with [Marko Bjelonic] of ETH Zürich describes progress by one of many research teams working on the problem.

For many of us, the first robot we saw rolling on powered wheels at the end of actively articulated legs was when footage of the Boston Dynamics ‘Handle’ project surfaced a few years ago. Rolling up and down a wide variety of terrain and performing an occasional jump, its athleticism caused quite a stir in robotics circles. But when Handle was introduced as a commercial product, its job was… stacking boxes in a warehouse? That was disappointing. Warehouse floors are quite flat, leaving Handle’s agility under-utilized.

Boston Dynamic has typically been pretty tight-lipped on details of their robotics development, so we may never know the full story behind Handle. But what they have definitely accomplished is getting a lot more people thinking about the control problems involved. Even for humans, we face a nontrivial learning curve paved with bruised and occasionally broken body parts, and that’s even before we start applying power to the wheels. So there are plenty of problems to solve, generating a steady stream of research papers describing how robots might master this mode of locomotion.

Adding to the excitement is the fact this is becoming an area where reality is catching up to fiction, as wheeled-legged robots have been imagined in forms like Tachikoma of Ghost in the Shell. While those fictional robots have inspired projects ranging from LEGO creations to 28-servo beasts, their wheel and leg motions have not been autonomously coordinated as they are in this generation of research robots.

As control algorithms mature in robot research labs around the world, we’re confident we’ll see wheeled-legged robots finding applications in other fields. This concept is far too cool to be left stacking boxes in a warehouse.

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Hackaday Links: November 29, 2020

November 29, 2020 by Tom Nardi 11 Comments

While concerns over COVID-19 probably kept many a guest room empty this Thanksgiving, things were a little different aboard the International Space Station. The four-seat SpaceX Crew Dragon is able to carry one more occupant to the orbiting outpost than the Russian Soyuz, which has lead to a somewhat awkward sleeping arrangement: there are currently seven people aboard a Station that only has six crew cabins. To remedy the situation, Commander Michael Hopkins has decided to sleep inside the Crew Dragon itself, technically giving himself the most spacious personal accommodations on the Station. This might seem a little hokey, but it’s actually not without precedent; when the Shuttle used to dock with the ISS, the Commander would customarily sleep in the cockpit so they would be ready to handle any potential emergency.

Speaking of off-world visitation, the Hayabusa2 spacecraft is nearly home after six years in space. It won’t be staying long though, the deep-space probe is only in the neighborhood to drop off a sample of material collected from the asteroid Ryugu. If all goes according to plan, the small capsule carrying the samples will renter the atmosphere and land in the South Australian desert on December 6th, while Hayabusa2 heads back into the black for an extended mission that would have it chasing down new asteroids into the 2030s.

Moving on to a story that almost certainly didn’t come from space, a crew from the Utah Division of Wildlife Resources recently discovered a strange metal monolith hidden in the desert. While authorities were careful not to disclose the exact coordinates of the object, it didn’t take Internet sleuths long to determine its location, in part thanks to radar data that allowed them to plot the flight path of a government helicopters. Up close inspections that popped up on social media revealed that the object seemed to be hollow, was held together with rivets, and was likely made of aluminum. It’s almost certainly a guerrilla art piece, though there are also theories that it could have been a movie or TV prop (several productions are known to have filmed nearby) or even some kind of military IR/radar target. We may never know for sure though, as the object disappeared soon after.

Even if you’re not a fan of Apple, it’s hard not to be interested in the company’s new M1 chip. Hackers have been clamoring for more ARM laptops and desktops for years, and with such a major player getting in the game, it’s only a matter of time before we start seeing less luxurious brands taking the idea seriously. After the recent discovery that the ARM version of Ubuntu can run on the new M1 Macs with a simple virtualization layer, it looks like we won’t have to wait too long before folks start chipping away at the Walled Garden.

In the market for a three phase servo controller? A reader who’s working on a robotics project worth as much as a nice house recently wrote in to tell us about an imported driver that goes for just $35. Technically it’s designed for driving stepper motors, but it can also (somewhat inefficiently) run servos. Our informant tells us that you’d pay at least $2,000 for a similar servo driver from Allen-Bradley, so the price difference certainly seems to make up for the hit in performance.

Finally, some bittersweet news as we’ve recently learned that Universal Radio is closing. After nearly 40 years, proprietors Fred and Barbara Osterman have decided it’s time to start winding things down. The physical store in Worthington, Ohio will be shuttered on Monday, but the online site will remain up for awhile longer to sell off the remaining stock. The Ostermans have generously supported many radio clubs and organizations over the years, and they’ll certainly be missed. Still, it’s a well-deserved retirement and the community wishes them the best.

How To Improve A Smart Motor? Make It Bigger!

November 7, 2020 by Donald Papp 25 Comments

Brushless motors can offer impressive torque-to-size ratios, and when combined with complex drive control and sensor feedback, exciting things become possible that expand the usual ideas of what motors can accomplish. For example, to use a DC motor in a robot leg, one might expect to need a gearbox, a motor driver, plus an encoder for position sensing. If smooth, organic motion is desired, some sort of compliant mechanical design would be involved as well. But motors like the IQ Vertiq 6806 offered by [IQ Motion Control] challenge those assumptions. By combining a high-torque brushless DC motor, advanced controller, and position sensing into an integrated device, things like improved drone performance and direct-drive robotic legs like those of the Mini Cheetah become possible.

IQ Vertiq 6806 brushless DC motor with integrated controller, driver, and position sensing.

First, the bad news: these are not cheap motors. The IQ Vertiq 6806 costs $399 USD each through the Crowd Supply pre-order ($1499 for four), but they aren’t overpriced for what they are. The cost compares favorably with other motors and controllers of the same class. A little further than halfway down the Crowd Supply page, [IQ Motion Control] makes a pretty good case for itself by comparing features with other solutions. Still, these are not likely to be anyone’s weekend impulse purchase.

So how do these smart motors work? They have two basic operating modes: Speed and Position, each of which requires different firmware, and which one to use depends on the intended application.

The “Speed” firmware is designed with driving propeller loads in mind, and works a lot like any other brushless DC motor with an ESC (electronic speed control) on something like a drone or other UAV. But while the unit can be given throttle or speed control signals like any other motor, it can also do things like accept commands in terms of thrust. In other words, an aircraft’s flight controller can communicate to motors directly in thrust units, instead of a speed control signal whose actual effect is subject to variances like motor voltage level.

The “Position” mode has the motor function like a servo with adjustable torque, which is perfect for direct drive applications like robotic legs. The position sensing also allows for a few neat tricks, like the ability to use the motors as inputs. Embedded below are two short videos showcasing both of these features, so check them out.

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PyBot Is A 3D Printed SCARA Arm For The Masses

October 19, 2020 by Tom Nardi 10 Comments

We’ve all seen videos of blisteringly fast SCARA arms working on assembly lines, and more than a few of us have fantasied about having that same kind of technology for the home shop. Unfortunately, while the prices for things like 3D printers and oscilloscopes have dropped lower than what many would have believed possible a decade ago, high-performance robotics are still too pricey for the home player.

Unless of course, you’re willing to build it yourself. The PyBot designed by [jjRobots] is an open source robotic arm that should be well within the means of the average hardware hacker. One could argue that this is a project made entirely possible by desktop 3D printing; as not only are most of the structural components printed, but most of the mechanical elements are common 3D printer parts. Smooth rods, linear bearings, lead screws, and NEMA 17 motors are all exceptionally cheap these days thanks to the innumerable 3D printer kits that make use of them.

A custom control board keeps the wiring tight.

Those who’ve researched similar projects might notice that the design of this arm has clearly been influenced by the Mostly Printed SCARA (MPSCARA). But while that robot was designed to carry an extruder and act as a 3D printer, [jjRobots] intends for the PyBot to be more of a general purpose platform. By default it features a simple gripper, but that can easily be changed out for whatever tool or gadget you have in mind.

In the base of the arm is a custom control board that combines an Arduino M0, an ESP8266, and a trio of stepper motor drivers. But if you wanted to build your own version from the parts bin, you could certainly wire up all the principle components manually. As the name implies, the PyBot is controlled by Python tools running on the computer, so it should be relatively easy to get this capable arm to do your bidding.

We’ve seen some impressive 3D printed robotic arms over the years, but the simplicity of the PyBot is particularly compelling. This looks like something that you could reasonably assemble and program over a weekend or two, and then put to work in your ad-hoc PPE factory.

Educational Robot Teaches With Magnets And Servos

October 8, 2020 by Lewin Day 1 Comment

Teaching kids about robotics gives them valuable skills for their futures, and is generally pretty darn fun for all involved, too. However, teaching children often involves taking a bit of a different tack to educating college students, and more of a hand-holding approach is often needed. This robot project is an attempt to do just that, using some classic time-honored techniques and a unique method of propulsion.

The Magnetic Motion Robot, or MMR, is very much a DIY project. Built out of hand-cut plywood and assembled by lacing together individual modules, it’s a low-cost entry into the world of educational robotics. Rather than wheels or motors, it instead uses electromagnets mounted on servo arms to get around. Switching the magnets on and off, and moving the servos in time, allows the robot to pull itself along a ferromagnetic surface.

The robot is outfitted with buzzers and LEDs, and using these features creates further programming challenges for students. Naturally, there’s also a line-following program, which is a great way to begin educating kids about autonomous robot operations. It’s all run from an Arduino Nano, programmed with Makeblock’s special building-block programming software.

While its DIY nature makes assembly a little more involved than the average off-the-shelf kit, it does present its own learning opportunities such as soldering and the integration of hardware. Educational robots will continue to be popular and fun long into the future; we’re a particular fan of sumobots ourselves. Video after the break.

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Robot Cat Takes Inspiration From Nature

September 30, 2020 by Lewin Day 3 Comments

Oftentimes, a project starts with a clean sheet of paper, and we set out wildly sketching towards the goal in our minds. However, it can pay to do your research first, as [Chen Liang] demonstrates with this great robotic cat build.

[Liang] began the project after being dissatisfied with existing robot animals they’d seen online. Rather than simply attempt to build a cat from memory, instead, [Liang] decided to first study a real cat to ensure the resulting robot would bear real resemblence to its biological inspiration. [Liang]’s focus was on the skeleton, as replicating the way the real skeleton worked would create a robot with more authentic movement.

Using 3D printed parts and many, many servos, we think [Liang] has done an admirable job at creating a basic robot cat platform. With an ESP32 running the show, the cat can be posed using a web interface to control the servo positions of its various joints. We look forward to future upgrades that enable fluid movement and other capabilities, particularly involving the onboard camera.

It’s not the first robot cat we’ve seen, and it’s likely it won’t be the last. If you’ve got one living in your own lab, drop us a note on the tipline. Video after the break.

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The Jolly Cart-Pushing Robot

September 14, 2020 by Orlando Hoilett 4 Comments

[Lance] loves making simple robots with his laser cutter. He finds great satisfaction from watching his robots operate using fairly simple mechanisms and designs a whole slew of them inspired by different animals, including a dinosaur and a dragon. His latest build is a jolly cart-pushing robot.

He cut each piece of his robot on his laser cutter, and in order to get the pieces to fit snugly together he made each tab a little bigger than its corresponding slot, ensuring the piece wouldn’t fall out. This also helps account for the loss in the material due to kerf, which is the bit of each piece of material that gets lost in the cut end of the laser cutter.

Making his robot walk was mostly as easy as attaching each leg to a simple DC motor such that the motor would rotate each leg in succession, pushing the robot along. From time to time, [Lance] also had to grease the robot’s moving parts using a bit of wax to help reduce friction. He even used a little rubber band to give the robot some traction.

[Lance] did a pretty good job detailing the build in his video. He also linked to a few other fun little robot designs that could entertain you as well. Pretty easy hack, but we thought you might find the results as satisfying as we did.

Robot companions may be here to stay. Time will tell.

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