The (Robot) Body Electric

If you deal with electronics, you probably think of static electricity as a bad thing. It blows up MOSFETs and ICs and we take a lot of pains to prevent that kind of damage. But a start-up company called Grabit is using static electricity as a way to allow robots to manipulate the real world. In particular, Nike is using these robots to build shoes. You can see a demo video, below.

Traditional robots use human-like hands or claw-like grippers to mimic how humans handle material. But Grabit has multiple patents on electroadhesion. The original focus was wall-climbing robots, but the real pay off has been in manufacturing robots since the electrostatic robots can do things that mechanical hands are a long way from duplicating.

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Hackaday Prize Entry: A Six Axis Robotic Arm With Fingertip Control

If you were a child of the 1980s whose fascination extended to the contents of your local Radio Shack store, you may remember the Armatron robot arm as a particular object of desire. It was a table top robot arm operated not by motors or a microcontroller, but by a clever set of gears directed manually from a pair of joysticks. If you took a look at it with an eye to control from your 8-bit home computer you were likely to be disappointed, but nevertheless it was an excellent toy.

The Armatron may be long gone, but if you hanker for a similar device you should take a look at [3D Meister]’s finger controlled six axis arm. This is an arm similar to the Armatron in size, but with far more capabilities. Control is via cable loops to sliders at the arm’s base, and in addition to the usual arm movements there is an extra loop which can be used to operate any of a selection of tools including a gripper, a magnet, and a clipper. The video below the break shows the arm in action, and for the faint-hearted it should be noted that it contains the gratuitous death of some innocent plants.

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Evezor Robotic Arm Engraves 400 Coasters

When you’re running a Kickstarter for a robotic arm, you had better be ready to prove how repeatable and accurate it is. [Andrew] has done just that by laser engraving 400 wooden coasters with Evezor, his SCARA arm that runs on a Raspberry Pi computer with stepper control handled by a Smoothieboard.

Evezor is quite an amazing project: a general purpose arm which can do everything from routing circuit boards to welding given the right end-effectors. If this sounds familiar, that’s because [Andrew] gave a talk about Evezor at Hackaday’s Unconference in Chicago,

One of the rewards for the Evezor Kickstarter is a simple wooden coaster. [Anderw] cut each of the wooden squares out using a table saw. He then made stacks and set to programming Evezor. The 400 coasters were each picked up and dropped into a fixture. Evezor then used a small diode laser to engrave its own logo along with an individual number. The engraved coasters were then stacked in a neat output pile.

After the programming and setup were complete, [Andrew] hit go and left the building. He did keep an eye on Evezor though. A baby monitor captured the action in low resolution. Two DSLR cameras also snapped photos of each coaster being engraved. The resulting time-lapse video can be found after the break.

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Pneumatic Rotary Vane Joints Lend A Gentle Helping Hand

Festo has released a video showing the workings of their BionicCobot, a pneumatic robot arm developed for lending a helping hand to humans at a workstation. Since it works intimately with humans, it has to be safe, producing no harmful movements, and reacting when encountering an obstacle such as an arm containing delicate human bone. This it does using pneumatics and rotary vanes.

Rotary vane in action
Rotary vane in action

The arm has seven degrees of freedom, three in the shoulder, one in the elbow, another in the lower arm, and two in the wrist. But you won’t find any electric motor or gears. Instead each contains a rotary vane. Compressed air pushes on both sides of the vane. If the air pressure is the same on both sides of the vane then it doesn’t rotate. But with more pressure on one side than the other, the vane rotates. This is much like in a human arm, where two muscles work together to bend the arm, one muscle contracts while the other relaxes. Together they’re referred to as an antagonistic pair. In addition, each joint has a circuit board with two pressure sensors for monitoring the joint.

Using pneumatics, if an obstacle is encountered, the pressure can be released, making it instantly safe. And air being compressible, the joint can behave like a spring, further adding to the safeness. By controlling the pressure, the spring can be made more or less tense.

You can see it in action in the video below the break, along with more details such as how they use ROS, the popular, open system Robot Operating System which we’ve seen here a lot before, along with their Festo valve bank, one of which our own [James Hobson] used for his slick elysium exoskeleton. The video also covers how they handled running the hoses, the kinematics and the UI software.

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Walter is the Slickest Retro-Futuristic Robot Arm

[Jochen Alt] is on a roll. We just covered his ball-balancing robot, Paul, only to find his phenomenal six-DOF robot arm in full retro style. Its name is “Walter” and it’s done up in DDR style (the former East Germany), in painted, 3D-printed plastic. The full design and build documents are an absolutely amazing resource if you’re into robot arm or legs.

In particular, the sections on trajectory planning and kinematics are fantastic. If you’re interested in robot motion planning by Bezier curves, you know where to go. (We’ve always wanted a Bezier-curve 3D printer slicer, but that’s another story.) The construction is also top-notch here, and the attention to detail that went into this arm is phenomenal. It’s all done with stepper motors and geared belts, which allow each of Walter’s joints to be driven by a motor that’s one joint further upstream than would be the case if it were designed with servos. [Jochen] even went so far as to expose the belt in some places to show off the gearing. Walter is worth checking out.

Even if you’ll never build such a fancy robot arm, you should read through the docs just to appreciate all of the thought and work that went into this very refined and simple-from-the-outside design. If you’d like to start out on the simple side of the spectrum, check out these robot arms made of office supplies or a desk lamp. Once you’re ready for your second arm project this short list, some of which [Jochen] mention in his writeup, should get you up and grasping. And do check out his balancing bot, Paul.

Tying Knots with Industrial Robots

We’re not ashamed to admit that we desperately want a pair of high-end industrial robot arms to play around with. We don’t know where we’d put them — maybe the living room? — but we know that we’d figure something out.
This demo aims to get Boy Scouts interested in robotics by applying the beastly arms to something that all kids love, learning to tie knots. (If you ask us, they’ve got it backwards.) Anyway, there are two videos embedded below for you to peek at.

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From IKEA Lamp To Robot Arm

We’re used to projects that take everyday household objects and modify or enhance them into new and exciting forms that their original designers never intended. A particular theme in this endeavour comes from the IKEA hacking community, who take the products of the Swedish furniture store and use them for the basis of their work.

A particularly inventive piece of IKEA hacking is a project from [anastas.car], a low-cost 3D-printed robot arm based on Ikea Tertial lamp. The lamp in question is a relatively inexpensive spring-balanced desk lamp that when looked at in another light has all the metalwork ready-cut for a 5 degrees of freedom robot arm when combined with 3D-printed servo holders for five servos at its joints. The resulting design has all files available on Thingiverse, and judging by the video we’ve posted below the break makes for a rather effective arm.

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