James heads - Brett Klisch & James Powderly

James robot skin - Brett Klisch & James Powderly
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David Hanson robot

Hanson's Einstein with Hubo Walking robot
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Harvey Pekar by various artists

Paul McCarthy, Mechanical Pig, 2005 - animatronics by David Kindlon
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Schedule:

12-2pm Exhibition of work by Robot Clothes and panel participants
2- 3:30pm Public design review of Robot Clothes’ Inside Out Life Story
4-6pm Panel hosted by Robot Clothes

Panelists:
David Hanson, David Kindlon, Harvey Pekar & Joyce Brabner, Sal Restivo & Robot Clothes (Michelle Kempner and James Powderly)

Collaborators/Artists:
Dustyn Roberts, Seth Frader-Thompson, Tom Kennedy, Sameer Kapoor, Todd Polenberg, Jessica Findley, Jim Kempner, Brett Klisch, Mike DeFeo

The concepts and tools of AI, human-computer interaction and situationally-aware machines and mechanisms continue to move further from the realm of science-fiction and government labs and into the hands of artists, musicians, writers, scientists and DIY enthusiasts. As this happens robots and new media are being used to redefine artistic mediums and create highly-personal expressions. Automated Biography is a creative technology symposium exploring the role of technology in the conception of autobiographical and biographical artworks. Selected robotic artworks and works in progress will be exhibited and discussed. The panel and group discussion will introduce several examples of alternative uses of technology and media to explore illness, identity, politics and life in the margins of culture. The panel at 540 West 21st Street is open to the public with a suggested don!
ation of $5.

Robot Clothes is an art and commercial research and development partnership, Their commercial clients, include fortune 100 companies, NASA and internationally renowned artists, such as Diller + Scofidio and Miranda July. Their artworks and collaborations with artist have been exhibited at the Whitney, PS1, The Sculpture Center, Artbots and MOMA Queens. James Powderly helped develop the Rock Abrasion Tool currently on Mars.

Since graduating from RISD, David Hanson has worked as a designer, sculptor and robotics developer in the entertainment industry for clients including Walt Disney Imagineering, Universal Studios and MTV. His robotics have won numerous awards and his technical papers have been published internationally. To see high resolution images of Hanson’s robots, please turn to Human-Robot.org.
http://www.portfolios.com/DavidHanson

Cleveland, Ohio native Harvey Pekar is best known for his autobiographical slice-of-life comic book series "American Splendor", a first-person account of Pekar’s downtrodden life. The series has been published since 1976. In 1987, Pekar was honored with the American Book Award and in 2001 the series 25th anniversary was celebrated with a special issue. Pekar also collaborated with his wife, Joyce Brabner, on a book-length autobio comic "Our Cancer Year." http://www.harveypekar.com/

Starting his career as a mechanical designer of puppets, David Kindlon has since moved onto animatronics. Working in the film industry Kindlon has worked on such major features as Predator, A.I, I, Robot, Godzilla and Day of the Dead. For the last two years he has been working with artist Paul McCarthy, building robust robotic mechanisms to animate McCarthy’s work.

Dr. Sal Restivo is Professor of Sociology and Science Studies in the Department of Science and Technology Studies at Rensselaer Polytechnic Institute in Troy, New York. Trained and educated in sociology, anthropology, social psychology, and history, he is a "social theorist" and specializes in social studies of science, mathematics, and mind. He has won numerous awards and fellowships for his research.
http://www.rpi.edu/dept/sts/faculty/biosketches/restivo.html

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The Dimension BST is a great machine. It’s in the small-company price range and capable of producing functional prototypes with just a little post-build finishing and assembly. For exhibition or theatrical prop quality pieces, the surface finish is pretty crude. Curved surfaces are ribbed. Flat surfaces have thin patches where you can see the honeycomb subsurface. The limited build area often requires parts to be divided into multiple prints. The following is some step-by-step instruction in how Michelle and I clean-up the poor surface finish of simple FDM parts and seam two parts together.

This process is courtesy of FX artist and sculptor Brett Klisch.

The object we are demonstrating this process on is a replica 1/3 scale model of our living room table that Michelle is making for the
set of our current project.

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2. The tools we use:
a. Rigid Putty Knife
b. Glazing Putty by Bondo
c. Sand paper (250 – 400 Grit, Wet-sanding pad)
d. Locking pliers
e. 5-Minute Epoxy
f. Dust Mask
g. Latex Gloves
h. White, Black or Grey Primer
i. Paint color of you choice

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3. Putty
Apply the glazing putty directly to the surface of the piece. Squeeze out a small smear of putty on the part from the tube. Use the putty knife to spread it around. Try to spread a little bit of putty across as large a surface area as possible. You should be able to see the plastic surface through the translucent layer of putty. Remember to always close the tube between smear applications. The air will thicken the putty and it won’t spread around as well. Let the putty dry for 5 to 10 minutes.

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4. Sand

Use 250 grit sand paper to sand the putty layer smooth. Sand in small circles until the surface is very smooth to the touch.

5. Repeat Steps 3 and 4 two or three more times depending on the roughness of the original surface.

6. Prime and sand

Once you have gotten a few layers of putty on the piece to fill in the crack, apply 3 or 4 coats of primer in whatever color you'd like. Between each coat sand the painted surface with 300 - 400 grit sandpaper. Let the paint dry for 15-20 minutes before you handle or sand the part.

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7. Join

To join the two parts: mix up a batch of 5 minute epoxy. Apply a thin layer to both of the surfaces you want to join. We used the locking pliers to hold the parts in place. This is key when joining two parts. You have to find some way to preload the two surfaces together for 30-60 minutes. It is best to let it sit for a few hours to make sure the bond is strong.

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7. Repeat Steps 3 - 6 three or four times until the seem between the two parts in nearly invisible.

8. Once the primer surface is dry, you can apply your top coat of paint. In our case we used glossy white since our table is metal with a white powder coat. We applied three layers of white gloss, sanding the surface with a 400 grit sandpaper between every layer but the last. Finish off with your final layer of top coat.

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Be prepared for the inevitable scratch or chip. That is just life.

And don't be surprised if someone kicks you to the curb because of the fumes.

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When we finish the table, I will upload some images of the completed project and you can see Michelle’s gilded table legs.

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LessEMF - Source for conductive fabrics and velcro. For $10, they offer a fabric sampler to try out different materials.
Mood Fabrics - Our favorite fabric store. For our pockets, we used denim and regular pocketing. Sometimes you can find conductive silk organza at Mood, so bring your multimeter.
Botani - Botani only sells buttons. They sell traditional metal snaps in bulk.
Newark in One - Good source for conductive epoxy and electronics supplies. We used conductive epoxy to attach the snaps to the 3D printed LED holder.
L.C. LED and LSDiodes LED resources

Conductive thread - The conductive thread we used, did not work well in small amounts so we replaced it with fine gauge wire. There are some conductive threads and information available online:
Lamé saver
Intro to Wearable Technology

Step-by-step pocket instructions:

1. Cut out pocket pieces from fabric and pocketing. To make a pattern, draw out the size and shape of the pocket, then add 5/8" around all edges for seam allowances. Press the 5/8" seam allowances down on all sides with an iron.
   [pocket pattern]

2. Attach conductive velcro to both sides of the pocketing. This will be where the battery is attached later on. We recommend using the loop side of the velcro to the pocketing. We attached the velcro to the pocketing using regular thread on a sewing machine.
   

3. Using conductive epoxy, attach velcro to both sides of a 3 volt battery. Make sure that the velcro does not touch the outer ring of the battery or it will short the battery. The photo shows a battery with loop side on the battery, but hook works better to minimize the chance of a short circuit.
   

4. Next, we cut conductive fabric out for the front and back of the pocket on the laser cutter. The fabric can also be cut the traditional way, with scissors. The conductive fabric is going to be part of an electronic circuit so it has to be continuous. That is why all the letters in the graphic are attached to each other.
   

5. Attach the conductive fabric to the pocket material, in our case denim, with regular thread. Both pocket pieces should have conductive fabric sewed to it. Make sure the fabric will overlap the velcro on the pocketing when it is all put together. Sew conductive thread creating continuity between the conductive fabric and the velcro on the inner pocketing for both sides.
   
   

   
   

6. We made a plastic housing for the LED using the 3D printer. With regular 5 minute epoxy, we attached an LED to the housing. With conductive epoxy, we attached 2 female snaps to the housing. Afterwards, always check for continuity with a multimeter.
   
   
   

7. Attach two male snaps to the front of the pocket for a place to snap the LED assembly to. First attach the snaps with regular thread and then go over it with conductive thread. One snap should sit on the field of conductive fabric and the second snap should sit on the denim. Make sure there is no continutiy between the two male snaps.
   

8. On the pocketing material, attach a male snap that lines up on the inverse side of the denim snap on the front of the pocket. Attach it with regular thread first and then use conductive thread to create continuity between the male snap on the front on the pocket with the male snap on the inside of the pocket.

9. On the pocketing for the back of the pocket, attach a female snap that meets up with male snap you just added to the front pocketing. After attaching the snap with regular thread to the pocketing, use conductive thread to create continuity between the snap and the conductive material on the back of the pocket.
   

10. Sew the pocketing material to the pocket material and sew up the pocket around the outside edges.
    
    

Pockets from the workshop

Download all the CAD files for the LED mount by clicking here (includes Inventor files, STLs, STEP & IGES files)

In June we decided to take a new approach. Michelle is going to build a smaller, less expressive “michelle robot” and I am going to build a bigger and pretty expressive “james robot”. The james robot is going to be built around cheap available motors that can be augmented to provide for closed-loop control. Closed loop just means that our control system will have active feedback that will dynamically control the motor speed, acceleration, etc. When I say closed loop I don’t mean RC servo’s or DC servos with potentiometers. RC servos have a limited form of positional control but no user accessible feedback loop. And potentiometers aren’t very good positional feedback for our purposes as they are noisy, wear easily and are not reliably repeatable.

For the james robot, the first step was determining a size large enough to accommodate our motor assemblies, harnessing, etc., but small enough to remain very light and be considered miniature. So I shopped around for motors that would be cheap, small and enable closed loop control via encoders. At Honeybee we use Maxon and MicroMo motors. These are great motors and you can find them in small packages, but the cost was prohibitive for both our project and the low-cost DIY robot we want to make available.

So I decided I would try to find separate shaft encoders and motors and try to make an assembly (or a couple varieties of assemblies) that would couple them via gear pairs or pulleys or whatever. We tried out a number of different motors and finally decided we would use a few gearmotors from solarbotics. We chose the solarbotics motors because they had a range of reductions, sizes, shaft output orientation and were overall very light, very cheap and very available.

Check out solarbotics here

The GM3 224:1 gearmotor and the GM14 Sanyo 297.1:1 gearmotors have seen the most action so far in our arm assembly. The GM3 (and the GM2, GM8 and GM9) are all similar, use the RM3 DC brushed servo motor and have plastic gears and housing. They all also have an output D-through- shaft that can couple to an encoder shaft. The regular output shaft is also easy to couple to and the motor is pretty easy to mount with two built-in mounting through-holes. They are capable of 50 in*oz of torque, with a kludge clutch rated at 60 in*oz and a weight of 1.31ounces. They cost ~ $6.00 each.

The GM14 is smaller, lighter and has metal gears. This is a very small motor, small enough to universally make people say “cute” when they see it. It produces ~40 in*oz of torque and weighs .29 ounces. The output shaft has a flatted side, so it is easy to mount to, though there isn’t much shaft axially in general. Not particularly easy to mount but it does have some mounting holes and can be mounted by putting the whole motor in a rectangular recess. They cost ~ $25.00.

Both motors run on ~5VDC and draw current in the range of 100 ma to 600 ma.

I choose the U.S. Digital S4 miniature optical shaft encoder as the proprioceptive feedback device. This encoder is cheap, small, very accurate, comes in a number of resolutions, is easy to mount and can be purchased with a gear bearing shaft so the encoder can handle a substantial radial load. They cost ~ $45.00.

Check out U.S. Digital here.

So with these motors in mind I started trying to build an arm starting with the assembly for the elbow of the james robot. I picked the elbow for no particular reason, but it turns out biomedical engineers also use the elbow diameter as a figure of merit for human factors engineering. It looks like the smallest I can make the elbow joint is ~2" diameter. I could go smaller but it will actually cost more, as the gearmotors I would need are real cute and realy pricey. I decided to lock the size at ~52% scale to the 50 percentile man age 20-65 as documented by The Measurement of Man and Woman You can look at the overall arm dimensions in the Arm_Dimensions.xls in the Arm section of the DIY robot KIT.

The following design represents our first generation robotic arm. The current design has 3 DOF not including the wrist and up to the shoulder. This arm allows for motion approximating the motion of a human arm, including bending the elbow, forearm pronation/supination and gross supination/pronation.

The overall integration of the arm with its actuators can be accomplished in under ten minutes not counting soldering of leads, cabling and harnessing. The following numbered list describes and illustrates the basic assembly and integration of the arm.

1. Collect all 7 ABS parts, 3 S4 shaft encoders, 2 GM14 small metal gearmotors, 1 white plastic GM2 gearmotor, 3 plastic gears, 2 plastic hubs, 2 #2 socket head cap screws and nuts, and a heavy duty 6” rubber band.

2. Insert S4 encoder 1 shaft into the 0.372” hole in the upper arm motor/encoder mount (Part 1) until the encoder is flush. Lock it into place with the nut using a small wrench or pliers.

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3. Insert S4 encoder 2 shaft into 0.372” hole in the upper arm mounting substrate (Part 2). Then begin to attach the encoder/motor mount (Part 1) to upper arm mounting substrate (Part 2) by lining up the two 0.115” mounting holes by inserting 1-1/2” #2 socket head cap screws through the upper arm mounting substrate and the encoder/motor mount.

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4. Insert motor onto #2 screws until flush with encoder/motor mount. Tighten down nuts with socket set or wrench. Insert the hubs (Hub 1 & 2) onto the GM2 motor and the encoder shafts. Stretch the rubber band from hub to hub such that the movement of one shaft is mechanically coupled to the other. I am going replace this eventually with a v-shaped drive belt made of rubber.

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5. Insert the shaft of the S4 encoder 2, while still mounted on the upper arm mounting substrate, into the 0.25 mounting hole on the gear feature at the bottom of the upper arm/shoulder rotational drum (Part 3).

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6. Next, insert the small, thin pinion gear (Gear 1) onto the D-shaft of the GM14 motor 1. Insert the motor into the motor cavity in the upper arm substrate (Part 2). You will need to help rotate the upper arm/shoulder rotational drum so the teeth of the pinion and gear will mesh.

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7. To finish the upper arm mate the other half of the upper arm substrate, the upper arm mating substrate (Part 4) to the upper arm mounting substrate. Use the motor and motor cavity as the alignment feature. I am going to add a latch to these parts very soon but for now fasten the two halves of the upper arm substrate together with rope, wire ties or rubber bands.

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8. Next grab the forearm mounting substrate (Part 5) and place the large pinion gear (Gear 2) vertically in the slot on the mounting substrate so that it is parallel and co-linearly aligned with the 0.372” hole on the mounting substrate. Insert S4 encoder 3 into the 0.372” hole on the mounting substrate and the 0.25” hole on the large gear. Use needle nose pliers to tighten the nut on the encoder.

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9. Insert the double flatted shaft of the GM2 motor 1 into the double flatted feature on the forearm mounting substrate.

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10. Insert the GM14 motor 2 D-shaft into the small, thick pinion gear (Gear 3). Insert motor 2 into the motor cavity on the forearm mounting substrate so the gear and pinion are aligned. You may need to help rotate the large gear so the gear and pinion teeth can mesh.

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11. Lay the Forearm rotational drum (Part 7) shaft and gear features so that the gear meshes with the thick pinion gear (Gear 3) and the shaft aligns and fits into the forearm mounting substrate shaft recess feature such that the forearm drum is secured in the X and Y planes.

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12. Finally, mate the forearm mating substrate (Part 6) with the forearm mounting substrate using the motor and motor cavity and the shaft recess as alignment features. As before, I am going to make a latch for this so use rope, wire ties and rubber bands to secure these two forearm substrates.

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In the next section I will illustrate and describe how to create and run the wiring harness for the arm, create service loops to accommodate rotational joints and how to properly solder the motor and encoder leads.

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All the arm design files can be found in the arm design zip files in the Arm section of the DIY robot KIT. The zips include STLs for printing at service bureaus on FDM machines or ABS 3D printers, IGES part files, Autodesk Inventor part and assembly files, part DWF files and DXF files. All zip files are named according to file type and revision. Download the latest revision as we will be constantly upgrading. For more information on the design, fabrication and/or assembly of the 1ST generation arm please send me an email. The files are licensed under the creative capital non-commercial, attribution, share-alike contract. If you use or modify the design we would love to hear about it and we will be glad to host your new designs (and sing your praises) on the Lab Blog.

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Check out our work samples on our site:

Sample 1
Sample 2

Download them to your desktop if you don't mind so we don't go over our server bandwidth...

Inside Out Life Story is the product of our life with Crohn's Disease. Crohn's Disease is chronic inflammation of the digestive tract, usually affecting the small intestines and colon. Crohn's and a related disease, ulcerative colitis, are the two main disease categories of a group of illnesses called inflammatory bowel disease. Both diseases involve an abnormal response by the immune system where it attacks healthy intestines.

I found out about the bike ride while James was in the hospital with a scary flare-up. I was feeling inspired to get active in the Crohn's community and I saw the ride featured on the CCFA web site. I signed us up, with James’s permission (despite what he now claims) and we began training. Our training did not progress too far, we did two official training rides (25 miles and 45 miles) and then rode our bikes to work a few days a week leading up to the ride.

When it was time to begin the ride, I was sure that we could in no way possibly complete this ride. We had not trained enough, James was still on a lot of medicine, the temperature was unexpectedly in the 90s and my tummy hurt. But we showed up and we completed the ride. It was a great experience and we met a lot of amazing people with IBD or with close family with IBD.

Basically, actuators make up components like arms and legs.
Arms and legs make up humanoid robots.
Other set pieces will get an appropriate class later.
Each humanoid robot contains the methods necessary to perform the choreography.
There will be a choregraphy interface with subclasses that implement it. Each robot will register with the choreographer. Associated music will also check in (meaning we need the appropriate music classes). The choreographer will keep the movements in synch with the music.
My coworker also made the point that since the robots are performers, I can think of the class design as a theater. If I am missing a class, think of who would do that in the theater and add that class.

see class diagram

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What we will not describe how to do in this tutorial:

1. Build a part in 3D software.
2. Set-up a Dimension 3D printer.
3. Install the 3D printing software on a computer.
4. Perform maintenance or anomaly resolution on the 3D printer

I will try to get around to addressing some of these issues eventually, especially common maintenance problems and how to handle them. This tutorial will give you much of the information you need to take a 3D drawing and get it printed, given access to the software and a fully functioning Dimension BST 3D printer

First some general info about the 3D printer.

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The printer works by laying down a thin bead of plastic from the extrusion head. The extrusion head has two degrees of freedom (DOF) that translate to the X and Y dimensions in 3D Cartesian coordinates. The part is built on a platform that translates, or moves up and down, to enable a third or Z dimension. The piece is built from thin beads of ABS plastic model material. The printer also uses ABS plastic support material during the building of the part in order to temporarily create a part base, fill holes and support thin or small protrusions during the printing. The plastic beads build-up horizontally in the X and Y dimensions creating layers in the Z dimension. The layer height has two options and can be set in software. The layer size and bead height translate to the minimum resolution you can achieve in a part given the optimal build orientation.

Layer Height: .010” or 13”
Minimum bead size: 2 times the Layer height (.020” or .026” Z Dimension)
Maximum part size (3D printer build area): 8” Width x 8” Depth x 12” Height

Don’t expect to be able to print small protrusions and details < .020”

Here are some examples of parts we've printed and the printer in action:

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So Michael has designed a 3D part to upgrade his custom-designed and built computer desk. The part is designed to hold the consumer off the shelf (COTS) computer tray to the desk frame, which is made of industrial plumbing pipe and joints.

Click to view a larger image of Frumin's Table

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So lets follow Michael through the process of producing this part.

1. Design the part in your 3D modeling software of Choice and Export the File as a .STL file

Michael designed the part using 3D modeling software and exported the model as a .STL file. Frumin used Rhino. He chose to increase the number of facets during the export process. In terms of the 3D printer, I think facets can be thought of as the smoothness of the plastic finish on the curved or rounded surfaces. Too few facets means curved surfaces fabricated in a horizontal orientation will look under-sampled, low-res, steppy. So, you should increase the number of facets if your export function gives you that option. The downside is the file size increases. And typically that isn’t a problem for most people these days. Once you have your .STL file you can then take it to the computer on which you have loaded Catalyst, Status, CMB viewer and the Dimension BST administrative software. Eyebeam will have a dedicated 3D printing computer in the near term. Ask Jonah or Michael about the machine is you would like to use it.

This is an image of Frumin's part, which he saved in Rhino as an .STL file, in an open source 3D modeling program called Blender.

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2. Turn on the Dimension BST 3D printer. First, on the back of the machine at the bottom right, find the power relay switch and move it to the up position. Then find the red on/off switch on the side of the printer at the lower right and flip it to the on position. You should see the display light-up and indicate that the machine is warming-up. IT takes ~15-20 minutes for the machine to warm-up. It will indicate it is ready for printing by entering idle mode. This will be indicated on the front display.

The machine runs through many calibration procedures during start-up and this process take a few minutes. Be patient. Do not restart the machine, or cycle the power, during the start-up process. Wait until the machine indicates it is in Idle Mode before you turn the machine off. The printer doors locks occasionally during building and calibration. Do not force the door open.

The power breaker is the switch on the left of the image below. It should be in the up position as pictured.

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The power switch is red and located on the side of the machine.

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3. Open you the Catalyst Program from the Desktop Icon or applications start menu.

If you designed your part using metric dimensions you may get a warning your part is much larger than the printer build area. It will ask if you would like to convert your units to metric. Click Yes.

4. Navigate to File>Open and choose the STL file you wish to print

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5. You should see you part in the in 3D in the main window. Navigate to View>Fit Envelope. You can also choose to zoom in and out from the View menu.

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6. You should see your part within a constraining box that corresponds to the build area of the printer.

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If you part is larger than the build area you should navigate to STL>Size and Unit and adjust the scale factor. The smallest scale factor is 0.10.

7. Now you need to orient the part. Michael’s part is best built with the XY plane oriented vertically. We can achieve this by navigating to STL>Orient by facet>Top. The cursor will turn to a question mark. Click on the face of the obiect you wish to orient to the front (or whichever direction you choose). In this case it was the front XZ plane that Michael wanted to orient to the normal to the top of the constraining box. You can choose to orient whichever face of the part you choose to be facing either the top, bottom, front, back, left or right. You can also orient your part using the STL>Rotate command. You can also choose to Restore original orientation under the STL menu as well.

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Part orientation is as much an art as a science. You can choose the orientation to optimize the surface finish, part strength and build time. Often times choosing one aspect mean sacrificing on another. A few simple suggestions: for smoother curved surfaces orient them vertically. For stronger holes and cylindrical protrusions orient them horizontally. If you orient a part vertically it will take longer to build. It may take experience to determine the best orientation. Or you can talk to me, Jamie, Michael, or someone else with some experience printing parts. You can also look at the Dimension Model Building Techniques presentation that is on top of the printer. I will try to get an electronic copy of this presentation to attach here.

8. Now set you build parameters, which are located in the main window inside the right hand frame. Michael chose:

Modeler: Dimension BST
Layer resolution: 0.010
Part surface: Best vertical quality
Part interior style: Sparse
Support Style: Break-away

The Modeler Field should read “Dimension BST”.

You can set your Layer Resolution to either 0.010 or 0.013 depending on the desired smoothness, your part tolerances and the desired build time.

The Part Surface field can either be set to “Best vertical quality” or “Best horizontal quality”. The best vertical quality means that each additional layer is created at a 90 degree offset to the previous layer. This results in a better horizontal finish. The best horizontal quality means that each additional layer is created at a 45 degree offset. This results in a better horizontal finish.

The Part interior style can be set to “Solid – normal” or “sparse”. If the part is going to need to react in loads you should choose a solid interior style. The spare interior style builds up a mesh (as opposed to a solid fill), so your part will be more brittle and have less stiffness. Using a sparse interior style will reduce material use and build time. This is good for form and fit testing.

The Support Style field can be set to either “Sparse”, “Basic”, “Surround” or “Break-away”. Basic is the easiest to remove, uses little material and reduces time. When in doubt default to Basic. Sparse uses little material and reduces build time but is not good for small or detailed parts. Surround is used for creating a scaffold-like supports. It uses a good deal of material, increases build time but it very useful for printing long thin parts in a vertical orientation. Break-away is similar to sparse but creates support in pillars. This way you can break-off a larger section of disconnected support material at a time. It isn’t recommended for small or detailed parts.

9. It is time to build you CMB file by clicking on the green flag icon. This will create your part layer by layer and display it in the main window. The red area of the part is model material and the grey area of the part is the support material. This will also open the Pack and Download Window and the Status Window. You can move your part around on the platform in the Pack and Download Window, or use the add icon to add more parts to the current queue.

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This creates the file that is downloaded to the printer. You can look at the build time in the Pack and Download window, estimated finish time and change your job name. You can check the operational status of a particular modeler (3D printer) in the status window. The current Modeler at Eyebeam is named “TheMicrolith3”. In the main window you can use the Display Layer Icons above the main window to look at the part slice by slice as the 3D printer will see it. You can click on the Display bottom layer icon and then scroll through the part layer by layer using the Display next layer icon. This may allow you to catch possible mistakes that may occur when 3D model surfaces have gaps of other inconsistencies. This will also give you a sense of how the 3D printer actually produces the part using the model and support material.

10. You can now send the part to the printer. Click on the Build current job icon. This will open a dialog box that indicates the download in ongoing. Once the CMB file has been downloaded to the printer the software will then open the status dialog window (if it wasn’t already open) and indicate that the build is pending. Except for checking the status of your job or building another part, you are now finished with the software.

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11. Go to modeler and insert a plastic modeling base. The modeling bases are located in the cabinet beneath the 3D printer. Open the printer door. Insert the trays tabs into the grooves in the Z platform inside the printer. The front of the modeling base should be flush with the front of the Z platform. Rotate the two retainers on the front of the Z platform to the up position to lock the modeling base into place. Close the door. For more information on inserting the modeling bases consult the Dimension BST User Guide located on top of the printer.

The modeling bases are reusable but must be cleaned of model material after each use. After many uses the trays will become damaged. If a base looks badly scratched across most of its usable build area, use a new base. Alert Jonah or Michael if we are running out of modeling bases.

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12. Now check the status display to see if it has received your job and is waiting for the build to be started locally (i.e. on the printer). It should indicate that it is “Ready to Build” and the command display will give you the option of choosing to “Start Model”. Press the button associated with the “Start Model” command display. The display should change to indicate it is building the part.

It may indicate that the machine is warming up. It will run through several calibration procedures like finding the home position for each axis and cleaning material off the extrusion head. Be patient. This will take awhile.

13. Sit back and let the printer go to work. Typical build times are 2-5 hours. You can check to see the status of the build by looking at the Status software from any computer. From the 3D printer locally, you can check the amount of time left or material usage by pressing the buttons associated with the “Show Time” and “Show Material” command displays respectively.

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14. When the part is done the status dispaly will indicate “Completed Build” and the door will unlock allowing you to remove the part. The status display will then indicate that the machine has completed the build and it will aks you if the part is removed. Press the button associated with the command display “Yes” if you have removed the part and closed the door.

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15. Remove part from base and remove the grey support material from the part.

To accomplish this task we have a set of exacto knives and dental picks, scrapers and spatulas in the 3D printer cabinet. To remove most parts from the modeling base, you just need to torque the modeling base gently as you would an ice tray to unstick the ice cubes. You can also use the dental spatulas of the paint scraper to pry the part up. Gently. To remove the support material, gently use the dental picks or exacto knives to remove the grey support material from through-holes and crevices. Use the dental spatulas to remove the support material base from the part. Be patient and gentle or you can easily damage you part.

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16. Clean the modeling base, the machine and the work area as needed. You can clean the modeling material off the modeling base with the paint scraper or exacto kives. You can treat the modeling base less gently than your part, but try not to create deep ruts, or gouges in the modeling base. Put the tools back into the 3D printer cabinet.

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17. Turn the printer off and on as you would a CPU. If you know the printer will not be used for a few days you can turn the printer of using the on/off switch. The command display will indicate the printer is shutting down and cooling down. Wait for the display screens to go dark and then move the power breaker on the back of the machine to the down position.

Here is a before and after shot to wrap up frumin's mind blowing part building experience:

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The Observer Pattern defines a one-to-many dependency between object so that when one object changes state, all of its dependents are notified and updated automatically.

The Strategy Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.

For the purpose of our software, I'm not sure if we can use this pattern. A contender for this pattern is motors. Let's suppose that motors have enough in common that they warrant having one motors superclass. We can extend the motor superclass with a servo class and a stepper class. Now if everything about these motors is basically the same except for how they return their position, we could make a Position interface. Then we could make two classes that implement Position with the appropriate behaviors.

I'll have to learn more about the components in the project to make these kinds of decision, but hopefully by describing it here I am absorbing the concept a little bit better.

Jon Kessler

Jennifer & Kevin McCoy

The McCoys are a married couple whose work includes miniature sets and robotic cameras. They also draw from personal experiences in their work such as a traffic jam during their second date.

First I set up a Java environment on my computer. I installed the Java 1.4 SDK and the Eclipse SDK. I had not used Eclipse before, but it makes tasks like creating getters and setters and compiling easier. Eventually, I think I will need to install Apache and Tomcat to run the code on my machine.

I found some robot code on a CMU web site. It includes an example of implementing a serial port interface in Java via a C dll. This might make sense because we already have serial code in C. Here’s part of the Java code:

public synchronized class serialPort
extends java.lang.Object
{
// open serial port at specified baud with other
// appropriate parameters. returns:
// 0 on success
// -1 on failure to open serial port
// -2 on failure to read port state
// -3 on failure to set port state
// coms are: 1 = "COM1"; 2 = "COM2" et cetera
// baud rates are: 1 = 9600; 2=19200; 3=38400;
// 4=57600; 5=115200; 6=230400
public native int openSerial(int comNum, int baudSpec);
public native int closeSerial();
// returns 0 on success or -1 on failure to send byte
public native int sendByte(int theByte);
// initialTimeout is measured in milliseconds //
// returns -6 on failure to set timeout, 0 on success
public native int setReadTimeout(int initialTimeout);
// returns -1 in error or timeout, else returns int
// between 0 and 255
public native int readByte();

static {
System.loadLibrary("sserial");
}

}

sserial is the name of the dll.

Apparently, Java has come out with a javax.comm package for serial communication. That might be a little more efficient than loading a C dll.

Eclipse SDK

But I planned on baselining shape memory alloy (SMA) actuators and stepper motors into the research as they both had desirable qualities and I am already pretty familiar with servo and hobby servo motor performance and control.

SMA was desirable from the standpoint of cost, quiet operation, compact size, strength and similarity to the human muscle actuation. Basically, you apply a current across muscle wire, a brand name pre-shaped SMA, and you get a small thermally-triggered contraction in the wire at about 70C or 90C depending on the type. Once the circuit is opened, the wire cools and begins to return to its normal length with some hysteresis depending on the mechanical loading and thermal environment on the wire.

An almost comic link on SMAs:
http://www.robotstore.com/shapememoryalloys.asp?afid=home

I set up two experiments using muscle wire from the robot store (see our current baseline document for ordering information). I built a 5 degree-of-freedom (DOF) arm from Fimo clay and wire. Michelle had already built me two previous arms in Fimo in order to determine the ideal DOFs we thought we would need to make a generally expressive arm with a range of motion visually similar to a human arm. I saw two potential areas where SMAs might be useful on the arm: the full contraction of the deltoid muscle and the forearm pronation/supination via the pronator teres muscle.

The Deltoid

The Pronator Teres

The Supinator

The muscle wire was to provide a single degree of freedom, e.g. lifting the arm to the horizontal plane at the shoulder or forearm pronation respectively, while a spring was to enable the arm or forearm to return to a loaded home position.

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After multiple tests with poor results in terms of both desired motion and two fried slivers of large diameter, high-temp muscle wire, I simplified the test set-up to just experiment with muscle wire control and sensitivity:

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I have concluded that given the time we have SMA will be a pain in my ass for three major reasons:

1. They contract almost enough to achieve the desired motion but not quite. 3-5% of the total wire length is the suggested contraction in order to get the millions of cycles promised. You can achieve as much as 8% contraction but the lifetime of the actuator will be diminished.
2. They are hard to mechanically connect to the worksite due to their small diameter and operational temperature. They operate at 70C + and ABS plastic is only spec’ed to 60C. This could be remedied by thermally isolating the wire from the plastic mounting and connection features. With the Fimo arm, I used a barrel crimp and crimped a thin-gauge wire (26 AWG) in one side of the barrel with a doubled-up piece of muscle wire. I crimped a bent staple in the other end of the barrel. The staple connected to the eyelet features on the arm. This was clugey no doubt and broke many times during the research. A better solution would be to use a potting compound or epoxy to mechanically fix the wires, SMA and mechanical connections, but this would make it hard to impossible to replace burnt out wires.
3. SMAs are hard to control. One guiding principle in this effort has been to afford each actuator a method of keeping the control closed-loop. This means each actuator should have sufficient position feedback to implement a PID or other control algorithm. This is the minimum needed to make smooth, controllable and expressive motions. With the SMA, I would have to implement feedback via a strain-gauge or flex-sensor and it would need to be very responsive in order to keep contraction within the 3-5% range. And these guys are really sensitive in general to mechanical and electrical damage.

So no muscle wire.

This menas the overall minimum arm diameter and length need to be larger than we had previously thought. The motor and motor assembly diameter will be the primary discriminator in terms of arm diameter.

Now, we have three types of motors to work with: steppers, servos and hobby servos.

Steppers are desirable from the perspective of control and size. Even without feedback, you can construct a type of closed-loop control so you can adjust your step rate to create a movement envelope that is aesthetically pleasant. If you loose your place though, position error would build up fast and it would be hard to correct unless you just routinely returned to a home position identified via limit switch. Steppers are also commonly flat and compact. I found and purchased two Seiko 10mm, 20 steps per revolution stepper motors. These guys are “ahh cute” tiny and worked very well when tested. I used a stepper motor controller chip that Mike Passaretti, a CE colleague of mine at Honeybee, suggested. He let me use the chip evaluation board to test the performance of the motor.

http://allegromicro.com/sf/3967/
http://allegromicro.com/demo/apek3967slb-01.htm

The board worked great. The motor performed pretty well too. It could half-, quarter- and eighth-step and moved up to 1k hz across the full stepping range at under 3 Volts. Here are the problems with the stepper for me:

(I'll insert an image of board and test set-up here tomorrow)

1. They are really coggy when they rotate at the speed at which we would need them to move. Cogging means you can see or feel the rotational movement in discrete intervals corresponding to the internal magnet positions vs. continuous rotational movement. 20 steps per rev is good for such a small motor and even while eight-stepping, it looked jumpy and mechanical. Realism isnt necessary, but it didn’t look believable.
2. These motors have really bad documentation and some really undesirable minimum purchase amounts. I got these 10mm motors at a surplus store. They cant really be relied upon for future use. They don’t have any documentation in terms of torque, operation power, etc. I have found other similar size motors but they can only be ordered in 10,000 + units. The next size up in available stepper motors jumps to 1” + diameter sizes and twice the mass.

While steppers presented an attractive potential in terms of simple control with internal feedback, they also could be difficult to correct in terms of position error caused by slippage and the available steppers were not as compact as I had hoped.

So we arrive where we began. I have used servos with precision encoder feedback, both custom made and COTS, and hobby servos for actuation of less sensitive DOFs. This is an approach used pretty commonly by hobbyists and research scientists alike. Kismet uses maxon motors with optical encoder feedback for the sensitive DOFs, like the eyes, mouth and neck, but relegates the eyebrows, ears and lips to Futabo RC servos.

I know the range of sizes for RC servos:

http://www.aeromicro.com/Catalog/servos_108602_products.htm

I am going to continue investigating servo motors, particularly those with thru shafts, and add-on encoders like these:

http://www.usdigital.com/products/optical-encoders.shtml

In terms of the other arm DOFs and a general summary of the arm R&D:

1. The arm will have 5 DOF:
A. The equivalent to the Deltoid in order to raise the arm out from the body to the horizontal plane
B. The equivalent to the Coracobrachialis for raising the arm out in front of and perpendicular to the body also to the horizontal plane.
C. The equivalent to the Biceps brachii in order to enable pronation and supination of the upper arm
D. The equivalent to the Tricep and Brachialis for flexion and extension of the arm at the elbow.
E. And the equivalent to the Supinator and Pronator Teres for supination and pronation of the forearm.

The wrist will likely also have a single DOF (likely a pulley type assembly) that attempts to simulate to a limited extent the muscles controlling wrist extension/flexion and the fingers (Flexor digitorum sublimis, Flexor carpi ulnaris, Palmaris longus, Flexor carpi radialis)

The wrist and hand DOF and DOF D will require a right-angle conversion, likely a beveled gear and pinion assembly.