The Triple Delta Robot Arm (and Leg)

October 9, 2014 by Brian Benchoff 17 Comments

delta By now you’d think we’ve seen just about every means of robotic actuator possible. We have Cartesian bots, Stewart platforms, SCARA bots, Delta bots, and even some exceedingly bizarre linkages from [Nicholas Seward]. We’re not done with odd robotic arms, it seems, and now we have Delta-ish robots that can move outside their minimum enclosed volume. They’re fresh from the workshop of [Aad van der Geest], and he’s calling them double and triple Deltas.

Previous Delta robots have used three universal joints to move the end effector up and down, and side to side. They’re extremely fast and are a great design for 3D printers and pick and place machines, but they do have a limitation: the tip of a single Delta can not move much further than the base of the robot.

By adding more parallelograms to a Delta, [Aad] greatly increases working volume of a his robots. One of the suggested uses for this style of bot is for palletizers, demonstrated in the video below by stacking Jenga blocks. There is another very interesting application: legs. There’s footage of a small, simple triple Delta scooting around the floor, supported by wire training wheels below. It makes a good cat toy, but we’d love to see a bipedal robot with this style of legs.

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4 Axis Delta Router Says Hello World

February 12, 2014 by Adam Fabio 15 Comments

deltaRouter

[Bart] stood upon the shoulders of the delta 3D printer giants and created this 4 axis delta router. The router was originally created for ORD Camp, an invite only hackers gathering. Each year he creates a new thing with one main purpose: to spark conversation. In his own words “Practicality and suitability are way down the list, so go ahead and snark away. If you do, you are missing the point.”

[Bart] did things a bit differently with his delta. For motors, he went with non captive steppers. “Non captive” means that rather than a shaft, the motor has a hollow threaded nut which rotates. A lead screw (usually with an acme thread) is passed through this nut. As the motor’s nut turns, the screw is pushed or pulled through the motor, creating a linear actuator. The only major downside is that a non captive stepper motor can’t be adjusted by hand. The screw doesn’t turn and neither do any external parts of the motor. For structure, the router uses MakerSlide and v-grove wheels. The spindle is a simple brushless hobby motor and 30 amp speed control. Rather than the outrunner motors we’ve seen lately, [Bart] wisely chose an inrunner motor normally used on R/C cars. Inrunners generally have less torque than their outrunner counterparts, but they make up for this in RPM. [Bart’s] motor is capable of 30,000 RPM, which is plenty for spindle duty. We think the motor bearings will probably need an upgrade, as the original motor bearings weren’t designed for side loads. For a controller, [Bart] utilized an Azteeg X3 running Repetier.

The router made a great showing at camp, and [Bart] decided it needed a 4th axis. He sourced a rotary axis from eBay. To keep the software simple, he connected the rotary axis to the extruder outputs on his controller. He was then able to hack the mach3 wrapped rotary post processor to output extruder commands. The results look great. [Bart] says the system definitely needs a tailstock, and we agree. We’re looking forward to the next update on this machine!

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World Maker Faire 2013: The Sub-$500 Deltaprintr

September 22, 2013 by Brian Benchoff 30 Comments

There are a few delta bot 3D printers out there such as the Rostock which, while being a very nice printer, is still a little expensive. When [Shai] from SUNY wanted to use a 3D printer for his artistic and academic pursuits, he decided to build his own printer. Thus the Deltaprintr was born.

Instead of printed parts, the Deltaprintr uses laser cut and machined parts for just about all of its bill of materials. The three motors mounted in the base are connected to the delta arms with Spectra fishing line, thus getting rid of the ludicrous cost of belts of the requisite length.

Everything is Open Source, and the guys behind the project should be putting their printr up on Kickstarter sometime next month. Word is the entire thing should be sub-$500, and a little bit of guessing tells me that doesn’t mean $499.

RepRap Simpson Puts A New Spin On Delta RepRaps

September 18, 2013 by Adam Fabio 23 Comments

Just when you think you’ve seen it all in the 3D printer world, something new pops up! [Nicholas Seward] posted a video of RepRap Simpson, his latest project. Simpson is a delta robot – but unlike any delta we’ve seen before. Previous offerings vertical rails on which the arms travel. As you can see, this design mounts three articulated arms directly to the base of the printer, using steel cables as part of the joint mechanism.

Judging by [Nicholas’] posts on the RepRap forums, Simpson’s grounded delta design has already gone through a few revisions. The basic geometry though, has remained the same. [Nicholas] calls this edition a “Proportional Gear Drive Joint Simpson”. The name may not roll off the tongue, but the movements are incredibly smooth, organic, and fast.

As with any delta design inverse kinematics play a huge role in the software. [Nicholas] is trying to simplify this with an optical calibration system. For the adventurous, the equations are posted on the forums, and a python Gcode preprocessor is posted on Thingiverse.

Even Simpson’s base received special attention. It’s built from a water jet cut piece of basalt. We like the use of opposed helical gears on the large joints, as well as the guitar machine heads used to tension the cable drive. One thing we are not sure of is the longevity of system – will cable stretch play an issue? Will the printed parts suffer wear from the cables? Only time will tell.

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Delta-type 3D Printer Built Using Extruded Rails

June 2, 2013 by Mike Szczys 18 Comments

delta-3d-printer-extruded-rail

From concept to completion this delta-style 3D printer (translated) is a sweet build. The quality of the work comes as no surprise. We’re familiar with [Arkadiusz Spiewak’s] craftsmanship from that H-bot type 3D printer we saw from him back in April.

Planning started off with a render of the design using Blender 3D. Not only did this give him a 3D model to use as his building reference, but the animation framework allowed him to test the kinematics of the design. After ordering an extruded rail system and assembling the frame he found the pillars had too much flex to them due to the rails used on the top and bottom. The fix was to mill a top and bottom plate to stiffen things up. After testing out the motors and the extruder head mount he made one final design change. He exported his Blender design as dxf files to cut and weld an aluminum replacement for the extruder mounting platform. As you can see in this video, the preliminary results are looking good!

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Rusty Old Table Saw Turned Into A Workstation Worthy Of A Master Craftsman

February 19, 2013 by Mike Szczys 18 Comments

rusty-old-table-saw-turned-pro-workstation

Okay, first of all: holy crap! Even if you didn’t know this started as a rusty table saw, the workstation that came out of this project is just phenomenal. It really makes us wish we had looked around for a used model with a cast iron top instead of going for the cheap stamped metal one that was ready to use.

[Simon Leblanc] started with a Delta contractor’s saw that was rusty inside and out. The refurbishment began by removing the table and everything from the inside. The rods and gears were all cleaned up before he began to sand away the rust on the table itself. But obviously he didn’t stop with getting the saw to be functional again. He built a small set of cabinets to serve as the base for the saw. They went inside of this larger assembly that combines an MDF table top with an Accusquare rip fence to greatly increase the working surface of the tool.

Now he needs to start in on an extra fancy CNC jig for the thing.

[via Reddit]

Shakey Robot Plays Angry Birds

July 24, 2012 by Mike Szczys 18 Comments

At this year’s Pycon [Jason Huggins] gave a talk about his Angry Birds playing robot. He built a delta robot which includes a pen actuator for controlling a capacitive touch screen. The video after the break starts with a demo of the bot beating a level of Angry Birds on the iPad.

The idea behind the build is that robots like this could be used for app testing. I this case [Jason] has tweaked the servo commands manually to achieve the results. But during the talk he does demonstrate some machine vision to analyze and win a game of tic-tac-toe.

We do enjoy seeing the robot, but we’re not sold on the thought that testing will use robots. Perhaps there is a niche need for this type of thing, but we assume the majority of automated testing can be done in the emulator for the device on which you are developing. What we really want to know is how the capacitive stylus works. We didn’t catch him talking about it at all. We want a reliable, yet simple way to electronically trigger touchscreen inputs (along the lines of this project). If you know how [Jason’s] stylus is working please share your thoughts in the comments section.

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