Tabletop Handybot Is Handy, And Powered By AI

Decently useful AI has been around for a little while now, and robotic arms have been around much longer. Yet somehow, we don’t have little robot helpers on our desks yet! Thankfully, [Yifei] is working towards that reality with Tabletop Handybot.

What [Yifei] has developed is a robotic arm that accepts voice commands. The robot relies on a Realsense D435 RGB-D camera, which provides color vision with depth information as well. Grounding DINO is used for object detection on the RGB images. Segment Anything and Open3D are used for further processing of the visual and depth data to help the robot understand what it’s looking at. Meanwhile, voice commands are interpreted via OpenAI Whisper, which can feed prompts to ChatGPT for further processing.

[Yifei] demonstrates his robot picking up markers on command, which is a pretty cool demo. With so many modern AI tools available, we’re getting closer to the ideal of robots that can understand and execute on general spoken instructions. This is a great example. We may not be all the way there yet, but perhaps soon. Video after the break.

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Möbius String Robot Goes Round And Round

While it doesn’t look like a traditional robot, the hydrogel robot from [Zi Liang Wu] forms a möbius strip and can be activated by light. They also experimented with shaping the hydrogels as a Seifert ribbon.

The key is that the hydrogels contain gold nanoparticles. Light heats the gold particles and this causes the hydrogels to move. The connections between the strips of hydrogels causes them to move in predictable ways. You can see a video about the experiments below.

These robots aren’t going to be for warehouse or factory work. But they can do tasks like collecting plastic beads, something difficult for conventional robots to do. They also hope to demonstrate that these soft robots could work in the body for taking samples or delivering a drug, although it isn’t apparent how light would get to them inside your body.

The dark side of the material tends to turn towards the light. The continuous loop structure means it never runs to the end of its travel. Watching it move on a string is pretty impressive.

Crawling and slithering robots may be the answer for certain specialized applications. After all, it works well in nature.

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Emulating Biology For Robots With Rolling Contact Joints

Joints are an essential part in robotics, especially those that try to emulate the motion of (human) animals. Unlike the average automaton, animals are not outfitted with bearings and similar types of joints, but rather rely sometimes on ball joints and a lot on rolling contact joints (RCJs). These RCJs have the advantage of being part of the skeletal structure, making them ideal for compact and small joints. This is the conclusion that [Breaking Taps] came to as well while designing the legs for a bird-like automaton.

These RCJs do not just have the surfaces which contact each other while rotating, but also provide the constraints for how far a particular joint is allowed to move, both in the forward and backward directions as well as sideways. In the case of the biological version these contact surfaces are also coated with a constantly renewing surface to prevent direct bone-on-bone contact. The use of RCJs is rather common in robotics, with the humanoid DRACO 3 platform as detailed in a 2023 research article by [Seung Hyeon Bang] and colleagues in Frontiers in Robotics and AI.

The other aspect of RCJs is that they have to be restrained with a compliant mechanism. In the video [Breaking Taps] uses fishing line for this, but many more options are available. The ‘best option’ also depends on the usage and forces which the specific joint will be subjected to. For further reading on the kinematics in robotics and kin, we covered the book Exact Constraint: Machine Design Using Kinematic Principles by [Douglass L. Blanding] a while ago.

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This Robot Picks Locks, If You’re Very Patient

We all know the Hollywood trope of picking a lock with a paperclip, and while it certainly is doable, most reputable locks require slightly more sophisticated tools to pick effectively. That’s not to say that wire is off the table for locksports, though, as this cool lock-picking robot demonstrates.

The basics behind [Sparks and Code]’s design are pretty simple. Locks are picked by pushing pins up inside the cylinder until they line up with the shear plane, allowing the cylinder to turn. Normally this is done a pin at a time with a specialized tool and with a slight bit of torque on the cylinder. Here, tough, thin, stiff wires passing through tiny holes in a blade shaped to fit the keyway are used to push all the pins up at once, eliminating the need to keep tension on the cylinder to hold pins in place.

Sounds simple, but in practice, this looks like it was a nightmare. Getting five wires to fit into the keyway and guiding them to each pin wasn’t easy, nor was powering the linear actuators that slide the wires in and out. Applying torque to the lock was a chore too; even though tension isn’t needed to retain picked pins, the cylinder still needs to rotate, which means moving the whole picking assembly. But the biggest problem by far seems to be the fragility of the blade that goes into the keyway. SLA might not be the best choice here; perhaps the blade could be made from two thin pieces of aluminum with channels milled on their faces and then assembled face-to-face.

The robot works, albeit very slowly. This isn’t [Sparks and Code]’s first foray into robot lock picking. His previous version attempted to mimic how a human would pick a lock, so this is really thinking outside the box.

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Here’s How That Disney 360° Treadmill Works

One thing going slightly viral lately is footage of Disney’s “HoloTile” infinite floor, an experimental sort of 360° treadmill developed by [Lanny Smoot]. But how exactly does it work? Details about that are less common, but [Marques Brownlee] got first-hand experience with HoloTile and has a video all about the details.

HoloTile is a walking surface that looks like it’s made up of blueish bumps or knobs of some kind. When one walks upon the surface, it constantly works to move its occupant back to the center.

Whenever one moves, the surface works to move the user back to the center.

Each of these bumps is in fact a disk that has the ability spin one way or another, and pivot in different directions. Each disk therefore becomes a sort of tilted wheel whose edge is in contact with whatever is on its surface. By exerting fine control over each of these actuators, the control system is able to create a conveyor-belt like effect in any arbitrary direction. This can be leveraged in several different ways, including acting as a sort of infinite virtual floor.

[Marques] found the system highly responsive and capable of faster movement that many would find comfortable. When walking on it, there is a feeling of one’s body moving in an unexpected direction, but that was something he found himself getting used to. He also found that it wasn’t exactly quiet, but we suppose one can’t have everything.

How this device works has a rugged sort of elegant brute force vibe to it that we find appealing. It is also quite different in principle from other motorized approaches to simulate the feeling of walking while keeping the user in one place.

The whole video is embedded just below the page break, but if you’d like to jump directly to [Marques] explaining and showing exactly how the device works, you can skip to the 2:22 mark.

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3D Printed Wheels Passively Transform To Climb Obstacles

Wheels do a great job at rolling over all kinds of terrain, particularly if you pair them with compliant tires. However, they’re not perfect, and can get stumbled by things like large vertical steps. Enter the PaTS-Wheel — a compliant mechanism that can tackle such obstacles with ease.

The PaTS-Wheel takes advantage of printable flexural hinges. Under regular conditions, it exists as a simple round wheel. However, when presented with a step obstacle, its individual segments can bend and flex to grab on to the step and hoist the vehicle up. It all happens passively as a result of the wheel’s structure, no actuators or control system are needed to achieve this action.

The video below does a great job of explaining the concept in raw engineering terms, as well as showing it in action. If you really want to drill down though, dive into the research paper. The design outperformed smooth wheels and whegs in climbing ability, and was able to match smooth wheels in simple tests of flat ground power consumption. The results are very impressive.

We’ve seen other transforming wheels before, like these wheg-like constructions, but nothing so passive and elegant as these. Video after the break.

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An Elbow Joint That Can

We’re not certain whether [Paul Gould]’s kid’s prosthetic elbow joint is intended for use by a real kid or is part of a robotics project — but it caught our eye for the way it packs the guts of a beefy-looking motorized joint into such a small space.

At its heart is a cycloidal gearbox, in which the three small shafts which drive the center gear are driven by a toothed belt. The motive power comes from a brushless motor, which is what gives the build that impressive small size. He’s posted a YouTube short showing its internals and it doing a small amount of weight lifting, so it evidently has some pulling power.

If you’re interested in working with this design, it can be downloaded for 3D printing from Thingiverse. We think it could find an application in plenty of other projects, and we’d be interested to see what people do with it. There’s certainly a comparison to be maid over robotic joints which use wires for actuation.

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