Andrew Burks

Tag: Model

Vibratron: Fitting Through Doors

by on Jan.19, 2011, under RobOrchestra, Robotics Club, Vibratron

Something I never considered when designing previous versions of Vibratron was its ability to fit through doors.  While the old design could fit through a set of double doors, we wanted the entire robot to be able to fit through a standard door.  This change in criteria required some major changes in the design of a few parts of the Vibraphone.  It also allowed for a few other system upgrades in the process.  Keep in mind that all of the renders here do not include any foam/cloth skin that will be used to contain the balls.

Full Model No Skin - Iso

Giant Circle Full of Key Units

The large waterjet circle that held up all of the key units was three feet in diameter.  Combined with the overhang of some of the key units, the diameter of the robot was at nearly five feet.  Separating the giant circle into two large semicircles fixes the problem pretty easily.  Hand grips were added so that the semicircles could be carried easily.  Even though they are 25 pounds each, the semicircles can be carried close to the body with arms locked, which is a requirement for simple transportation of the machine.

Giant SemiCircle

Full Model No Skin - Topish

Fold Out Wings

Instead of the large fixed upside-down-umbrella style from the previous design, this design has four fold out “wings” that catch the balls and funnel them towards the center.  The overall diameter is six feet when open, but the wings can fold up completely vertically alongside the column.  Between each wing is a pie-wedge shaped piece of cloth or foam.  This has a duel purpose of funneling balls toward the center and regulating the deployment height of the wings.  When the wings are raised, the compliance of the cloth/foam will allow it to fold.

Full Model No Skin Collaped - Iso

Deeper Square Basin

The previous basin was a thin circle, but our research with the prototype of the recirculation system has suggested that we will need many more balls in the system to reach steady state.  A wide square basin rigidly integrated with the vertical columns can hold the necessary volume of balls.  Four trapezoidal sheets of plastic also keep the balls rolling towards the center of the basin.

Basin Closeup

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Vibratron Structure

by on Oct.12, 2010, under RobOrchestra, Robotics Club, Vibratron

While I had made some preliminary designs of the Vibratron structure a few months ago, I can now begin to finalize some of the key support structure as the ball dispensing mechanism is finalized. 

Key Unit

Experimentation showed us that the ideal location of the ball dispenser is with the tube perfectly vertical, six inches above the center of a key tilted at 45 degrees.  A modular unit consisting of 4 pieces of lasercut plastic and a gate mechanism was designed to hold the keys and gates in their proper relative positions.

Key Unit - Alone Iso

Key Unit Mounting

A large sheet of 1/4” thick aluminum will be waterjet into a shape that can hold 30 of these key units.  Each unit will be attached to the aluminum by two lasercut clips which are held down by cotter pins.

Circle with single Gate - Front Iso

Circle with single Gate - Back Iso

30 Key Units

With 30 key units on one large piece of aluminum, the weight of the entire assembly is already at 50 pounds with a diameter of over 3 feet.  In the future, the ball recirculation system (an Archimedes screw leading into a paintball hopper) will rise out from the middle of the aluminum circle, and the ball collection system (a foam floor to catch the balls) will stick out below and around the keys.

Circle with Gates - Overall

Circle with Gates - Detail - Front Depth

Circle with Gates - Detail - Back

180 pieces of plastic, over 90 of them unique

There are 6 pieces of lasercut 1/8” red acrylic in each of the 30 key units.  3 of those 6 pieces are unique.  1 of the other 3 pieces has 6 different sizes, and the final 2 are each repeated in all 30 assemblies.

Obviously I did not want to model 98 different pieces of plastic and insert them individually into models.  Fortunately, design tables in SolidWorks are very powerful.  In the end, I only needed to make 5 plastic parts and 5 obnoxious Excel spreadsheets to get an assembly (“Key Unit”) with 30 unique configurations.  Some of the plastic parts even have their note engraved into the side!

Design Table

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Why I Need a Better Computer

by on Jun.06, 2010, under Personal Projects, Workstation

Computing Needs

I don’t do that much with my computer.  I take notes in class with OneNote, and do schoolwork with Microsoft Office.  I browse the internet with Chrome, listen to music on iTunes, watch movies with KMPlayer, and chat with Pidgin.  My biggest computing needs come from 3D modeling in SolidWorks and its components, like the COSMOS FEA pack and the PhotoView 360 Rendering App.  These programs, which I frequently use for my projects, require a large amount of RAM and graphics processing capabilities.  Because there is no computer that is both portable enough to bring to class to take notes on and powerful enough to rotate a >1,000 part 3D model of a racecar, I am convinced that the best solution is to use two well synchronized computers for my two distinct use cases.

Current Computer: ThinkPad X61 Tablet

  • Windows 7 – 64 bit
  • Intel Core 2 Duo L7700 @1.80GHz
  • 4 GB RAM
  • Mobile Intel 965 Express Chipset Graphics
  • 12″ screen @ 768×1024
  • 320?GB ????rpm Hard Drive
  • Docking Station – DVD drive with CD-RW
  • Docking Station – Connects to External Hard Drives
  • Docking Station – Connects to 24″ Samsung monitor @ 1080×1920

Workstation Design

Graphics Card

My primary focus was a graphics card that would let SolidWorks run at its full potential.  I needed a workstation card with openGL support to get the most out of SolidWorks.  I decided on the NVIDIA Quadro FX 580 because of its balance between price and performance.  It connects with the PCI Express 2.0 x16 port, so it began to limit my motherboard options.

Processor

Running Finite Elements Analysis always hangs up my laptop (or crashes it) so I wanted a processor that could handle the load.  The Intel i7 family seemed to be my best bet.  I needed to choose between the i7 920 and i7 930, a difference of about 140MHz and $15.  I went with the 920 because it seemed like the more popular model, which would make community support when I try to overclock it much easier.

Motherboard

I wanted to find the cheapest Motherboard I could that would get me by.  I needed the 1366 socket for my processor, a PCI Express 2.0 x16 plug for my graphics card, and room for some RAM.  I found an ASRock board that had just what I wanted and had room for another x16 card with SLI support if I felt the need to expand.

RAM

When viewing a model in SolidWorks it loads the assembly and all parts and sub-assemblies and sub-sub-assemblies and sub-parts etc. into RAM.  in order to view the full model of the racecar, I wanted to make sure I had enough RAM.  Because the i7 is tri-channel, I thought 3 x 2GB sticks would be sufficient.  The motherboard wanted DDR3 RAM, so that’s what I got.

Heat Sink / CPU Cooler

Even though the i7 runs at 2.66GHz, because most of the cores arent being used all the time, it is very easy and standard to overclock them to about 4.0GHz.  However, I needed a good cooler to get there.  I chose the CoolerMaster Hyper 212 because of its good reviews and good value.

Power Supply

I wanted to make sure to leave room for expansion, so I didn’t skimp on the power supply wattage.  I found a great series of deals, sales, and rebates that ended up cutting the price of a CORSAIR 650 Watt power supply in half.  I might regret not paying a premium for modular wires, but I think it will definitely get the job done.

Hard Drive

Because I already have external hard drive with all of my data, I didn’t see the need for anything fancy.  I found a good deal on a 1TB 7200rpm hard drive that is more than enough for me.  I may regret not buying a small solid state drive to speed up the time it takes for me to boot and the time it takes to start programs.

Case

I wanted an inexpensive case that was portable enough to be moved once or twice a year whenever I change where I live.  I also wanted to avoid any cheesy gamer cases with blue lights and annoying bells and whistles.  The CoolerMaster 335 seemed like a good, plain, simple, robust, economic option.

Optical Drive

I never use CDs or DVDs.  At Carnegie Mellon, the internet and intranet are so fast that it doesn’t make sense to transmit data any way besides the campus network.  I will not install an optical drive in the workstation, but if I need a CD drive desperately, I can always link to the docking station on my laptop.  I’m planning on installing the OS with my roomate’s 8GB USB thumbstick.

Monitor

I’m going to be using the same Samsung 24″ 1080×1920 I already have with my laptop and docking station, except I can switch inputs between laptop and Workstation.

Keyboard and Mouse

While I plan on using the old wireless Logitech USB mouse I already have when I need to, I prefer the Trackpoint mouse on my Lenovo laptop.  It’s so much easier to transition from keyboard to mouse when the mouse is already next to your right pointer finger.  Temporarily I will borrow a roboclub keyboard, but eventually I might indulge in this keyboard from Lenovo.  Also, I know there is some software out there that can link my laptop to my Workstation and let me use the keyboard and Trackpoint on my X61 to control my Workstation

Summary

Specs

  • Windows 7 – 64 bit
  • Intel Core i7 920 OC @ 4.0GHz
  • 6 GB RAM
  • NVIDIA Quadro FX 580
  • 24″ screen @ 1080×1920
  • No Optical Drive
  • 1TB 7200rpm Samsung Hard Drive
  • Trackpoint keyboard?

Expectations

I expect that when I’m in my dorm I will be using this computer, controlled from my laptop input with some synch program running between them.  While on campus I can take notes/go online with my laptop, but remote into my workstation for any serious business.  While off campus, depending on the internet connection, I might still be able to remote into the workstation to do serious work if I needed to.  The last component (i7 920) should arrive Monday, and I look forward to putting this together in the robotics room with the help of my friends.

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