Could Your Next House Be Built From Giant Lego By An Inchworm Robot?

Well, it depends when you’re going to be househunting– if it’s anytime soon, Betteridge’s law applies, but if your time horizon is a ways further out, [Miana Smith] at MIT wants to make it happen. She’s got a paper out with an open-source inchworm robot designed to assemble structures from voxels– and what is a voxel but a giant, LEGO-esque brick?

There’s a demo video below, and it’s easier to understand the motion of this thing when you see it in action. The 5 degree-of-freedom MILAbot has actuators on both ends, and no traditional base– that’s the inchworm part. It grabs a brick while anchored to one part of the structure, then stays anchored to the new brick to keep building from that locale, so on and so on.

Note that we’re not talking about concrete bricks here, though conceivably you could use an inchworm-style actuator to assemble those. The ‘voxels’ in the study are engineered space-frame blocks which come together very easily, though admittedly would make for a very drafty home– you’d want to fill them with spray foam as a finishing step. So it’s more of a framing technique than a one-and-done thing. Still it is a technique that has something to recommend it compared to the 3D-printed concrete houses that get so much hype— and are already being torn down. 

For instance, the researchers find that weather the voxels are plywood, PLA, or metal, the resulting structure has less embodied energy than any concrete structure, with 3D printed concrete being worst option by that metric– though the balloon-frame stick-build we in North America consider “conventional” is still the lowest of all. On the other hand, that balloon-frame building takes a crew to put together, and labour is expensive compared to robots. At the moment, however, the study admits balloon-framing wins on price, but that doesn’t mean it always will, and it’s a fun hack regardless.

So while your next house might not be made of LEGO by a robot inchworm, we’re still grateful to [Miana] for the tip.

Most building hacks we see here are of the 3D printed variety, but don’t count out plain old dirt. For that matter, as long as someone is willing to live in it, anything can be a house– even an airliner. Continue reading “Could Your Next House Be Built From Giant Lego By An Inchworm Robot?”

A black and yellow robot dog stands in the middle of the floor, with a GoPro camera mounted on its back. A picture-in-picture view in the bottom left corner shows the view from the camera.

An Improved Robot Dog For Senior Design

[Aaed Musa] has been building robot dogs for a long time now, so it was only natural that he would make one for the senior design project of his mechanical engineering degree. Since this meant working with potential customers, the requirements were somewhat more stringent than for previous dogs, but [Aaed] and his team were able to deliver CARA 2.0, their most agile, versatile robot yet.

Based on conversations with potential customers, [Aaed] and his team aimed for a price around $1,000 USD, a weight under 20 pounds, and a durable design. Like the original CARA, this used capstan drives to actuate the joints, which reduced costs. The drives were printed in resin and powered by brushless drone motors. These motors were designed for speed, not torque, so the team had to rewind them with more wire, an ordeal which paid off by roughly tripling the torque. As far as durability, one joint motor was tested by running it continuously back and forth, and it lasted for over 1,000 hours without obvious damage.

Since the joints don’t contain any absolute encoders, each motor has to home on startup by extending to its limit, as detected by a rise in motor current. As a happy side effect, this creates a lifelike stretching motion on startup. Compared to the earlier iteration, CARA 2.0 takes shorter, quicker steps, and thanks to angled step movements can turn much more quickly. In testing, it originally skewed to the left, which turned out to be due to an asymmetric leg design. Once corrected, CARA 2.0 could walk in straight lines, walk sideways, turn in place, crouch, jump, and keep its balance on an inclined surface. It didn’t quite make the price goal, but $1,450 is still cheap for such a capable robot dog, and it reached every other customer requirement. Most importantly, all the team graduated.

For another take on a capstan-powered robot dog, check out Stanley. We’ve also taken a look at TOPS, one of [Aaed]’s earlier designs.

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PenPal, A Robotic Drawing Assistant

Emergent properties include examples like murmurations of starlings which can’t be predicted from looking at a single bird, weather which can’t be predicted by looking at a few air molecules, and consciousness which can’t be predicted by looking at a neuron. Likewise, when adding a new tool to a workflow, emergent properties can show up as well. A group at Chicago University developed a robotic drawing tool and a few artists developed some unique drawing methods using it.

The robotic pen uses a pair of tendons to extend the working end out a certain amount. From there it uses a set of servos to can be programmed to revolve around in a defined path, making repeating movements while the artist makes larger movements over the paper. Originally meant for shading, small circles or simpler back-and-forth movements were preset, but with full control over the pen’s behavior the artist can shift focus away to other tasks within the creative process. A study with ten participants was done which showed artists coming up with novel ways of using a tool like this, and others reporting that it’s almost like drawing together with another person.

Looking for novel ways that humans can interact with computers and robots can often lead to surprising outcomes like this. Members of this group aren’t new to novel human interface devices either; they’ve also built a squishy dynamic button as well.

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Robot Bird Decoys Work For Good

Usually, you think of bird decoys as being a tool to lure birds to an untimely encounter with a hunter. However, [Interesting Engineering] has a story about robotic bird decoys in Grand Teton National Park that are helping restore the dwindling number of sage grouse in the park.

While some decoys are static, others are motorized to replicate mating rituals. The goal: lure real birds to safer areas to breed. Particularly, they want the birds to avoid areas around the Jackson Hole Airport. The robots are built with help from local students and robotics teams. While some of the construction is made of fabric and foam, actual bird feathers are also used.

The robots mimic lekking behavior, a courtship ritual where male grouse do repetitive motions combined with recorded mating calls. This attracts other grouse and, of course, results in chicks who will be raised nearby.

Assuming the effort is successful, the same technique could help other areas where restored areas are difficult to repopulate. You can find more pictures on the Park’s Instagram, and the title picture is from that collection.

Usually, when we see something like this, the robot is trying to remove something dangerous to the endangered plant or animal, not attract them.

3D Printed Robot Arm Built For Learning Purposes

If you want to work with robots you can do all sorts of learning with software and simulation, but nothing quite beats getting to grips with real machinery. That was the motivation for [James Gullberg] to build this impressive robot arm. 

Featuring six degrees of freedom, the robot arm is mostly constructed of 3D printed components. This let [James] experiment with a wide variety of joint and reducer designs for the sake of learning and investigation. The base of the robot uses a fairly conventional planetary gear drive, while shoulder and elbow joints rely on split-ring planetary gearboxes to allow for high torque density with regards to size. [James] implemented a neat sensing technique here, integrating alternating magnets into the output ring gear which are monitored via a magnetic encoder. The wrist joint switches things up again, running via an inverted belt differential.

Running the show is an STM32 microcontroller, which talks to all the encoders, communicates with a Raspberry Pi over CAN bus, and handles all the necessary PID control loops and step generation for the drive motors. The plan is to run higher-level control on the Raspberry Pi which will run a ROS 2-based software stack. Already, the various joints look smooth and impressive in motion.

If you’re looking to learn about robot arms, you really can’t beat building one. We’ve featured a few projects along these lines before. Most of them aren’t exactly production-line ready, but they will teach you a ton about control, motion planning, and all sorts of associated skills. That experience can be invaluable if you intend to work with robots in industry.

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Real Robot Makes Debut In Programming Game

Sometimes the right tool for the right job appears almost out of nowhere. That was certainly the case for [Jonathan] who came across an unusual but well-designed robot at a secondhand shop. The robot needed a bit of work to get back into a usable condition, but after that it was ready for use. For such a unique machine, it needed a unique place to work as well, so in this build [Jonathan] uses it as a real robot to recreate a popular board game meant to teach programming to children.

In the original board game, called Robot Turtles, there are no actual robots. Instead, players use cards to control turtles to reach objectives in much the same way that a programmer would solve a similar problem with a computer. A board game with such a name almost demands a robot, so [Jonathan] found a larger playing surface in the form of soft matting blocks, each with a number or letter, that can be assembled into a grid. To make the game, he built a Python application on top of the interface he reverse-engineered in a previous build. It handles the robot interface, control, input, and a PyGame GUI. The game can either be played in real-time, or the robot’s moves can be queued.

In addition to keyboard input, the bot can also be controlled by putting cards from the actual board game itself on an NFC reader he made. [Jonathan] has a four-year-old at home, so he hopes that all of these projects will have an impression and encourage experimentation and discovery of computers and programming.

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Building A Robot Partner To Play Air Hockey With

Air hockey is one of those sports that’s both incredibly fun, but also incredibly frustrating as playing it by yourself is a rather lonely and unfulfilling experience. This is where an air hockey playing robot like the one by [Basement Builds] could come in handy. After all, after you finished building an air hockey table from scratch, how hard could it be to make a robot that merely moves the paddle around to hit the puck with?

An air hockey table is indeed not extremely complicated, being mostly just a chamber that has lots of small holes on the top through which the air is pushed. This creates the air layer on which the puck appears to float, and allows for super-fast movement. For this part countless chamfered holes were drilled to get smooth airflow, with an inline 12 VDC duct fan providing up to 270 CFM (~7.6 m3/minute).

Initially the robot used a CoreXY gantry configuration, which proved to be unreliable and rather cumbersome, so instead two motors were used, each connected to its own gearbox. These manipulate the paddle position by changing the geometry of the arms. Interestingly, the gearbox uses TPU for its gears to absorb any impacts and increase endurance as pure PLA ended up falling apart.

The position of the puck is recorded by an overhead camera, from where a Python script – using the OpenCV library running on a PC – determines how to adjust the arms, which is executed by Arduino C++ code running on a board attached to the robot. You could just copy this code yourself, but as the video makes clear, this is basically cheating as you don’t get to enjoy doing all the trigonometry and physics-related calculating and debugging fun.

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