Robot Arm Achieves Amazing Accuracy With Just Servos

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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3D Printed Gesture-Controlled Robot Arm Is A Ton Of Tutorials

Ever wanted your own gesture-controlled robot arm? [EbenKouao]’s DIY Arduino Robot Arm project covers all the bases involved, but even if a robot arm isn’t your jam, his project has plenty to learn from. Every part is carefully explained, complete with source code and a list of required hardware. This approach to documenting a project is great because it not only makes it easy to replicate the results, but it makes it simple to remix, modify, and reuse separate pieces as a reference for other work.

[EbenKouao] uses a 3D-printable robotic gripper, base, and arm design as the foundation of his build. Hobby servos and a single NEMA 17 stepper take care of the moving, and the wiring and motor driving is all carefully explained. Gesture control is done by wearing an articulated glove upon which is mounted flex sensors and MPU6050 accelerometers. These sensors detect the wearer’s movements and turn them into motion commands, which in turn get sent wirelessly from the glove to the robotic arm with HC-05 Bluetooth modules. We really dig [EbenKouao]’s idea of mounting the glove sensors to this slick 3D-printed articulated gauntlet frame, but using a regular glove would work, too. The latest version of the Arduino code can be found on the project’s GitHub repository.

Most of the parts can be 3D printed, how every part works together is carefully explained, and all of the hardware is easily sourced online, making this a very accessible project. Check out the full tutorial video and demonstration, embedded below.

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Robotic Arm Sports Industrial Design, 3D-Printed Cycloidal Gears

[Petar Crnjak]’s Faze4 is a open source robotic arm with 3D printable parts, inspired in part by the design of industrial robot arms. In particular, [Petar] aimed to hide wiring and cables inside the arm as much as possible, and the results look great! Just watch it move in the video below.

Cycloidal gearboxes have been showing up in robotic arm projects more and more, and Faze4 makes good use of them. Why cycloidal gears? They are readily 3D printed and offer low backlash, which makes them attractive for robotic applications. There’s no need to design cycloidal gears from scratch, either. [Petar] found this cycloidal gear generator in OnShape extremely useful when designing Faze4.

The project’s GitHub repository has all the design files, as well as some video demonstrations and a link to assembly documentation for anyone who would like to make their own. Watch Faze4 go through some test movements in the video embedded below.

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Robot Arm Sucks In A Good Way

Building a robot arm is fun, but no longer the challenge it once was. You can find lots of plans and kits, and driving the motors is a solved problem. However, there is always one decision you have to make that can be a challenge: what effector to put on the end of it. If you are [MertArduino] the answer is to put suction at the end. If you need to grab the right things, this could be just the ticket for reliably lifting and letting go. You can see a video of the arm in action, below.

The arm itself is steel with four servo motors and comes in a kit. The video shows the arm making a sandwich under manual control. We suspect he might have put it under Arduino control but there’s no sudo for making sandwiches.

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Don’t DIY This Surgical Robot At Home

The LVL1 Hackerspace in Louisville hosted a hackathon for useless and impractical devices a couple of years ago and this makeshift Duh-Vinci Surgical Robot was one of the “successful” results. While it’s not necessarily a project that should ever be used for its intended purpose, its miniature setup is certainly an interesting one.

The project builds on top of the MeArm Open Source Robot and a camera controlled by a Blynk board. Servos are wired into the base of each of the robotic arms for freedom in rotating. A separate microcontroller is used for the motor controllers for the arms and for the camera, partially due to the current draw for the camera power supply. The remote control system runs on an Android tablet and is used to control each of the arms.

The ESP32-Cam supplied video input is configured as a RTSP stream. As for the operation, while the movements are jerky and the range of dexterity limited, the robot is technically able to handle the sharps. Its final setup looks a bit like a deranged game of Hungry Hungry Hippos meets Operation and definitely not something to be making its way to surgical tables anytime soon.

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An Open Assistive Robotic Arm To Help People Feed Themselves

Despite being otherwise capable, not everyone is able to feed themselves. [Julien]’s robot arm project aims to bring this crucial independence back to those people. Assistive devices in this space do exist, but as always they’re prohibitively expensive and the approval process is a nightmare. The development of the arm started by working closely with people who needed it at a local hospital. We note with approval, quite a few cardboard mock-ups to get the size and shape right before more formal work was done in CAD.

The robot arm only has to support a very light payload so its construction can be quite light. A frame of steel rods or plywood is all that’s required. We like how the motion is transferred from stepper motors to the joints of the arm by generously sized timing belts allowing the weight of the arm to remain towards the base. The team behind the project has gotten it to a point, but they’re hoping it will inspire community involvement as they move forward with it.

It’s worth noting, this is not the first assistive eating aid we’ve covered.

Iron Man Puts Yet Another Hacker Up In Arms

When Iron Man movie came out, we’d bet there wasn’t a single hacker that left the theater without daydreaming about having a few robotic lab assistants of their own. But unlike most of them, [Tony-Lin] decided to turn his celluloid dreams into a reality and started work on his robotic arm, Abot.

Abot is built from a combination of 5 mm nylon panels and 3D printed parts. One thing we found particularly interesting about this build is that the motor reductions for the joints are done using stages of pulleys and GT2 belting rather than planetary gear boxes or cycloidal drives. This produces a lightweight and affordable build.

He also designed his own driver boards for each motor using the STM32. They communicate with a CAN bus which uses USB connectors, an interesting choice. Just make sure not to try and charge your phone with it.

We have to admit to a little jealousy that [Tony] is moved himself a bit closer to being Tony Stark than the rest of us are likely to get. We’ll just have to live vicariously through the documentation of his project.