Monday, 8 September 2014

Introducing Elvis

Elvis is a 6-axis robotic arm the size of a human arm, built from off the shelf electronics and laser-cut acrylic pieces, and is directly driven from Rhino + Grasshopper. This is the official introduction of Elvis 1.0.

Elvis is open source and shared under a GNU GPL v3.0 licence so you can download everything required to build and use it from its GitHub page. It is very much a work-in-progress, and a lot can be improved. Included in there is a basic template for an end-effector, you can build on top of that to suit whatever it is you want to do with it. You can also modify the basic design of the robot itself to suit your requirement.

Elvis Mission Control in Grasshopper

Why Elvis?

Robotics is an interesting area of design/fabrication research, and recent developments by the likes of ETH ZurichICD Stuttgart, Bot & Dolly, TU Delft and numerous others have created excitement and spurred curiosity around the interesting potential robotics has in design and architecture. But anyone who has ever setup a Kuka/ABB/etc. knows that programming one is no easy task. They're extremely capable, precise and sophisticated in what they can do, but they can take a while to setup making it difficult to test draft ideas and prototype in quick iteration. And that is assuming you are lucky enough to have ready access to a robotic arm -- which most designers don't.

Elvis was conceived to fit this need. It's small, light and portable, and is meant for quick prototyping & iteration -- hence the direct control from within Grasshopper. It is not meant to replace an industrial-grade arm: it is not as precise or as fast, it costs roughly 5% of the cheapest desktop industrial arm available, and it takes a person about 2-3 days to put one together.
Elvis's version of "Hello world" 

Technical Details

DOF/Axis: 6
Motors: 8 x Servos, Dynamixel AX-12A
Range: ~525mm for wrist Centre (diagram below explains in detail)
Cost: £480 (UK). Presumably cheaper in the US/Asia. Detailed breakdown here.
IK Solver: Trigonometric
Wrist Type: Spherical

Future Development

Broadly speaking, the precision of the arm needs to be significantly improved. As of now, there is backlash in the system caused by the servos, and there is also flex in the materials used to built the arm itself. Geometric changes can substantially reduce the material flex leading to improved accuracy. Eventually backlash could be reduced through more appropriate hardware.

Elvis uses servos that are capable of reading their positions, so within a tolerance, the arm already "knows" where it is. This could easily be used as a forward kinematic system to digitally read positions in space and generate gcode for larger arms, similar to the system proposed by Andrew Payne, with the added benefit of a 6th axis. A camera/leap/kinect/other sensory mechanism can be used to setup an enhanced feedback system giving it a more precise idea of where it is, where it should be or what it should do next.

There are some very good robot simulation tools available on Grasshopper such as Daniel Piker's LobsterRobots.IO's Godzilla, etc. Last I checked I was unable to use Lobster as the IK solver for Elvis because of Elvis's asymmetrical axis configuration. I haven't been able to test it with Godzilla as yet, but the intention is to make Elvis easier to use with all these fantastic tools already available.


The directors, tutors and students of AAVS Dubai and AAVS Lyon for being wonderful platforms to further the development of Elvis, and the ZHA_code bunch for the insights and stimulating conversations.

The AA Visiting School Dubai showreel about the process of building and using Elvis

Man vs. Robot: Haider and Elvis in an 'axis-fight' at the AA Visiting School Dubai

The Grasshopper control file can compute IK for given toolpaths and directly move Elvis on those paths.

Thursday, 23 January 2014

Fragile Beasts | Sculpting Paper

A short 3-day workshop at the Łódź University of Technology with a fantastic outcome. Together with 17 students, we managed to do some interesting exercises and build a 1.9m tall beast from half millimetre thick card paper. As evident in the diagrams, the beast was designed and modelled as a cluster of polyhedra, and then a series of scripts were applied to make it curved-foldable. 

Apart from how strong it was structurally (at least to support itself), there were two interesting outcomes of the workshop: In continuing the lineage of curved folding (previously here and here), this prototype proved that curved folded polyhedra can be aggregated to form more complex structures (albeit to a limited extent).

Secondly, it never fails to amaze me how nicely this shape lends itself to fabrication and quick assembly: this piece took about 5 hours of laser cutting time and a further 5 hours to fold, glue and assemble together; and all this by a group of 17 students who had never done any form of curved folding before.

Anetta Kepczynska-Walczak | Assistant Professor, Łódź University of Technology, Poland
Sebastian Bialkowski | Doctoral Candidate, Łódź University of Technology, Poland
Suryansh Chandra | Senior Designer, ZHA | Code, London

The Design Intention

The Design Process
The LaserCut Pieces Arrive in the Studio

The Folding Assembly Line

Because Folding is so much Fun :)

Uhu it Up: Gluing the Pieces that form a single Polyhedron 

Parallel Processing: Each Polyhedron could be Assembled with a Small Team of Just 2 or 3

Completed First Polyhedron

Being a Sunday, we Hogged the Entire Corridor of our Floor to Setup our Assembly Line

Joining the first two Polyhedra

Edges Lineup Well

Some Narrow Edges Weren't Conducive to being Folded too Sharply

The Base Coming Together

The Lower Half Forming the Base and the Feet done

The Base and one of the Polyhedrons of the Crown. The Leftovers from the Laser Cutter made into Wall Art on the Left.

A Keystone Piece Locks Everything Together

Alignment Checks

SuperLight: One of the Advantages of Paper

Almost there: The Crown Being put into Place

All done: The Entire Team

Thanks to everyone involved for making this possible and finishing up with such an astonishing outcome in just 3 short days, and to the avid photographers for documenting the entire workshop and taking the pictures you see above. A special thanks to Anetta and Sebastian for all their hard work, time and working relentlessly to make sure everything went smoothly, and all the things we took for granted.

I am curious to see how long this piece stands against the brutality of moisture and curious human beings, which over time will soften and distort the paper eventually buckling and deforming.