MIT’s Hair-Brushing Robot Untangles Difficult Robotics Problem

May 8, 2021 by 12 Comments

Whether you care to admit it or not, hair is important to self-image, and not being able to deal with it yourself feels like a real loss of independence. To help people with limited mobility, researchers at MIT CSAIL have created a hair-brushing robot that combines a camera with force feedback and closed-loop control to adjust to any hair type from straight to curly on the fly. They achieved this by examining hair as double helices of soft fibers and developed a mathematical model to untangle them much like a human would — by working from the bottom up.

It may look like a hairbrush strapped to a robot arm, but there’s more to it than that. Before it ever starts brushing, the robot’s camera takes a picture that gets cropped down to a rectangle of pure hair data. This image is converted to grayscale, and then the program analyzes the x/y image gradients. The straighter the hair, the more edges it has in the x-direction, whereas curly hair is more evenly distributed. Finally, the program computes the ratio of straightness to curliness, and uses this number to set the pain threshold.

The brush is equipped with sensors that measure the forces being exerted on the hair and scalp as it’s being brushed, and compares this input to a baseline established by a human who used it to brush their own hair. We think it would be awesome if the robot could grasp the section of hair first so the person can’t feel the pull against their scalp, and start by brushing out the ends before brushing from the scalp down, but we admit that would be asking a lot. Maybe they could get it to respond to exclamations like ‘ow’ and ‘ouch’. Human trials are still in the works. For now, watch it gently brush out various wigs after the break.

Even though we have wavy hair that tangles quite easily, we would probably let this robot brush our hair. But this haircut robot? We’re not that brave.

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Apple-Picking Robot Stems From Labor Shortage

May 1, 2021 by 35 Comments

Among all the job-related problems wrought by the pandemic, here is another one that comes as the result of people generally staying home: there are hardly any backpackers to do traditional transient backpacker jobs like picking apples. Researchers at Monash University’s Department of Mechanical and Aerospace engineering found a way to fill in the gap by building a pneumatic robot arm that can harvest an apple every seven seconds at top speed.

A suite of cameras and algorithms look for fruit amongst the foliage and carefully remove it by gripping it gently and twisting, much like a human would. In order to do this, the robot must consider the shape of the fruit, the way it’s hanging, and where to separate it from the tree while keeping damage to a minimum. A suction system helps pull the apple into the soft, four-fingered grip and then the arm twists and turns to deposit the apple into the bin.

There are a lot of upsides to this robot, including the fact that it works in any lighting and weather conditions and can ID an apple in less than 200 milliseconds. The only problem is that this operation results in the occasional missing stem — a cosmetic problem that sounds nit-picky, but would definitely prevent some stores from buying the fruit. Well, that, and there only seems to be one of these robots so far.

There are two videos after the break — a short one that gives you the gist, and a much longer one that offers a view of the suction cup, which emerges from the middle of the fingers like a xenomorph’s little mouth.

Some readers may be wondering why apples are still picked individually when shaking harvesters exists. “Shake-and-catch” tends to bruise apples, making them undesirable for produce sellers, however, apples destined for juicing have no issue with being handled roughly by the harvesters as shown in this fascinating harvest video. Robot grippers are gentle and we’ve seen all shapes and sizes that are suited to a particular need. When the needs are more general, rollers or squishy spheres might be the answer.

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Code Your Own Twitch Chat Controls For Robots — Or Just About Anything Else!

April 8, 2021 by 4 Comments

Twitch Plays Pokemon burst onto the then nascent livestreaming scene back in 2014, letting Twitch viewers take command of a Game Boy emulator running Pokemon Red via simple chat commands. Since then, the same concept has been applied to everything under the sun. Other video games, installing Linux, and even trading on the New York Stock Exchange have all been gameified through Twitch chat.

TwitchPlaysPokemon started a craze in crowdsourced control of video games, robots, and just about everything else.

You, thirsty reader, are wondering how you can get a slice of this delicious action. Fear not, for with a bit of ramshackle code, you can let Twitch chat take over pretty much anything in, on, or around your computer.

It’s Just IRC

The great thing about Twitch chat is that it runs on vanilla IRC (Internet Relay Chat). The protocol has been around forever, and libraries exist to make interfacing easy. Just like the original streamer behind Twitch Plays Pokemon, we’re going to use Python because it’s great for fun little experiments like these. With that said, any language will do fine — just apply the same techniques in the relevant syntax.

SimpleTwitchCommander, as I’ve named it on Github, assumes some familiarity with basic Python programming. The code will allow you to take commands from chat in two ways. Commands from chat can be tabulated, and only the one with the most votes executed, or every single command can be acted on directly. Actually getting this code to control your robot, video game, or pet viper is up to you. What we’re doing here is interfacing with Twitch chat and pulling out commands so you can make it do whatever you like. With that said, for this example, we’ve set up the code to parse commands for a simple wheeled robot. Let’s dive in.

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3D Printer As Robot: The Functograph

April 3, 2021 by 12 Comments

A 3D printer is really a specialized form of robot. Sure, it isn’t exactly Data from Star Trek, but it isn’t too far from many industrial robots. Researchers from Meiji University made the same observation and decided to create a 3D printer that could swap a hot end for other types of robotic manipulators. They call their creation the Functgraph. (Video, embedded below.)

Some of the tasks the Functgraph can do including joining printed parts into an assembly, breaking support material, and more. The surprise twist is that — unlike traditional tool change schemes — the printer prints its own end effectors together with the print job and picks them up off the build plate.

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Boston Dynamics Stretch Robot Trades Lab Coat For Work Uniform

March 31, 2021 by 30 Comments

Boston Dynamics has always built robots with agility few others could match. While great for attention-getting demos, from outside the company it hasn’t been clear how they’ll translate acrobatic skills into revenue. Now we’re getting a peek at a plan in an interview with IEEE Spectrum about their new robot Stretch.

Most Boston Dynamics robots have been research projects, too expensive and not designed for mass production. The closest we got to date was Spot, which was offered for sale and picked up a few high profile jobs like inspecting SpaceX test sites. But Spot was still pretty experimental without an explicit application. In contrast, Stretch has a laser-sharp focus made clear by its official product page: this robot will be looking for warehouse jobs. Specifically, Stretch is designed to handle boxes up to 50 lbs (23 kg). Loading and unloading them, to and from pallets, conveyer belts, trucks, or shipping containers. These jobs are repetitive and tedious back-breaking work with a high injury rate, a perfect opportunity for robots.

But warehouse logistics aren’t as tightly structured as factory automation, demanding more adaptability than typical industrial robots can offer. A niche Boston Dynamics learned it can fill after releasing an earlier demo video showing their research robot Atlas moving some boxes around: they started receiving inquiries into how much that would cost. Atlas is not a product, but wheels were set in motion leading to their Handle robot. Learning from what Handle did well (and not well) in a warehouse environment, the designed evolved to today’s Stretch. The ostrich-like Handle prototype is now relegated to further research into wheeled-legged robots and the occasional fun dance video.

The Stretch preproduction prototypes visible in these videos lacks acrobatic flair of its predecessors, but they still have the perception and planning smarts that made those robots possible. Those skills are just being applied to a narrower problem scope. Once production models are on the job, we look forward to reading some work performance reviews.

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Skid Steer Robot Chassis Takes A Beating

March 26, 2021 by 5 Comments

[Engineering After Hours] wanted a highly maneuverable robot chassis with a tight turning radius. Skid steering seemed to be the perfect solution, but the available commercial options didn’t take his fancy. Thus, a custom build was the answer – with impressive results.

The build packs two large RC motors, one for each side, with each driving two wheels through a belt drive. This reduces the electronics required to the bare minimum for skid steering. It’s all assembled within a plasma-cut metal chassis which is more than tough enough to take some hard knocks.

One of the primary goals on the build was to eliminate the risk of vibrations and shock damaging the motors and gearboxes. Many off-the-shelf designs couple the wheels directly to gearbox output shafts, potentially damaging the expensive components over time. In this design, a separate bearing assembly is used to take the load from the wheels instead.

It’s a great example of how an engineering-first approach can build a sturdy ‘bot with a minimum of fuss. Outfitted with some fat off-road tyres the performance is impressive, with the ‘bot having no trouble tearing it up in mud, snow, and water.

We’ve seen other great builds from [Engineering After Hours] before, like the active aero RC build. Video after the break.

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Robot Arm Achieves Amazing Accuracy With Just Servos

March 19, 2021 by 13 Comments

While few of us need robotic arms in our daily life, they’re a popular build with makers. Often, the most accessible builds throw together some RC servos and 3D printed parts, with limited accuracy a consequence of the components chosen. [Adam Bäckström] decided to take such a design and push it to its limits, however, with astounding results.

Part of the “special sauce” that makes this arm so capable is the custom optical encoders installed in the servo motors themselves.

[Adam]’s first robot arm build was a major disappointment, when the servos he had purchased for the build turned out to be terrible at holding an angle. With limited funds, he elected to improve on what he had, learning much about precision control techniques along the way. [Adam] taught himself how to implement industrial strength control loops using hobby hardware, by implementing additional encoders into servos and taking into account velocity and torque in addition to just position. With a magnetic encoder on the servo output shaft and a tiny optical encoder hand-built for inside the motor itself, much higher accuracy is achievable by allowing the control system to compensate for backlash.

The results are stunning, with [Adam]’s robot arm able to move incredibly smoothly throughout its range of motion. Perhaps the best demonstration of this is the pencil demo, where the robot arm delicately threads a pencil lead through the tip of a mechanical pencil without breaking. We’d love to see these techniques implemented more often; we imagine they’d be a great addition to a build like this one. Video after the break.

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