Andrew Burks

Tag: Structure

Finalized Vibratron Design

by on Jan.29, 2011, under RobOrchestra, Robotics Club, Vibratron

After a successful design review at the weekly Wednesday meetings, the final modifications were made to the Vibratron design.  After only a few major changes, the completed Vibraphone design looks something like this:

Full Iso

Instead of relying on tension in cables or cloth to keep the wings in their proper place, kickstands were added to each wing to keep it in the right position.  The kickstands also serve as the mounts for the cables that will be keeping the cloth tensioned.

Structure with Wires

All surface that could potentially come into contact with the steel balls are covered in a 1/8” thick layer of neoprene foam.  The foam will be attached with an adhesive instead of using hardware.  The longest diagonal of the final outer area of the robot are just under 8 feet.  Despite a few minor edits in the basin, the addition of the kickstands, and some other tweaks, Vibratron is still able to fold up into a neat 1’x1’x4.5’ column for storage and transport (excluding the two separate racks of key units).

From Below - Contracted

The entire structure is made out of 94 feet of aluminum 1”x1” angle, varying in thickness from 1/16” to 1/4”.  That aluminum has been ordered ($140.61) and fabrication of the main structure should be underway before mid-February.

With only $200 left in the $1,000 budget, the group still needs a 48’x36”x1/4” sheet of aluminum to waterjet into some very important pieces.  Using cheap 3003 H-14 aluminum sheet, it will cost $160 just for the raw materials for those pieces.  That leaves only $40 in the budget for fabric, foam, a power supply, steel cables, and other hardware.  Obviously the ends won’t be meeting, so we need to look for a donation of the aluminum plate.

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Vibratron Ball Collection Structure

by on Oct.19, 2010, under RobOrchestra, Robotics Club, Vibratron

Design

After bouncing off of the vibraphone keys, the ball bearings need a soft place to land and a central basin to roll into.  The basic idea behind the design was to make an upside-down umbrella, with the skeleton on the outside.  Stretching 1/4” foam between sections of aluminum angle is a cheap way to cover a lot of area.

Ball collector

Structure

Ball collector basin skeleton

Structure - Basin Detail

Incorporation into Full Model

While previous renders imagined the 180 pieces of acrylic supporting the keys to be red, clear acrylic being about 35% cheaper prompted a slight design change.  We should save about $100 by changing to 1/8” clear acrylic.

The full vibraphone is now 4.5 feet in diameter, and should be about 3.5 feet tall.  The rim of the basin is just 2 feet off the ground, which is good because want people to be able to look into the vibraphone.

Full Vibraphone (without recirculation screw and ball distribution)

Gates and Foam - Overall

Detail view of key unit/basin interaction

Gates and Foam - Detail

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Circular Vibraphone Preliminary Design

by on Jun.23, 2010, under RobOrchestra, Robotics Club, Vibratron

A completely axially symmetric vibraphone robot would be awesome.  We decided to move away from a big row of keys and towards a round plate of keys.  Here is a quick render of the key mounting structure and how it incorporates the ball retrieval and distribution system:

Structure

The large round plate is actually a 30-gon not a circle.  It is inscribed in a 32″ circle, and is 1/4″ thick.  There are 60 unique (thank you design tables!) plastic supports that slide onto notches in the aluminum.  Each plastic support has to be unique because of the awkward hole spacing in the individual keys.

There are already notches in the plastic for clips that should hold it into the aluminum plate (aka “Megaplate”).  However, depending on the design of the ball deployment mechanism, the retaining clips for the plastic plates should be incorporated into the support for the mechanism.  Here is a close up of the plastic supports:

Distribution

Finally, here is a close up of Mike Ornstein‘s ball collection and sorting mechanism.  It uses brushes from the bottom of doors to pull balls up an archimedes screw into a paintball-style hopper.

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Initial Vibraphone Designs

by on Jun.18, 2010, under RobOrchestra, Robotics Club, Vibratron

Overview: We are officially crazy

Animusic is a group that makes great computer animations involving “impossible” instruments playing great music.  While considering actuation mechanisms for the RobOrchestra Vibraphone project, somehow we decided it would be a good idea to do something similar to the instrument that takes center stage at 1:07 in Animusic’s “Pipe Dream”:

Details

Right now, 3/8″ diameter stainless steel balls are looking very promising.  Mike Ornstein, Dan Shope and I have subconsciously split up the work into 3 sections.  Dan is working on the mechanism to take the balls and dispense them onto the keys quickly and with a short reload time.  Right now, it appears that this will be accomplished with a group of DC motors.  Mike is working on the mechanism to lift the used balls back up and dispense them to queues leading into Dan’s mechanism.  This is most likely going to be done with an Archimedes screw and a paintball gun style dispenser.  I have been focusing on the structure of the whole mechanism and collecting the dispensed balls and funneling them to Mike’s mechanism.

The biggest problem I am facing with this design is the awkward hole arrangement in the keys.  I basically have two very awkward hole lines I need to support for both the naturals and the sharps.  A string pulled taut needs to go through the holes in the keys and the supports to hold up the key and let it vibrate naturally.  My initial concept involved about $60 of waterjet-cut 1/8″ ABS.  Here is a render of this initial design:

Initial Vibratron Key Support Render

This concept was that with angled plates in front of the keys sloping back toward the keys, as well as slopes over top of those angled toward the center, I could funnel all of the ball bearings into a channel between the two sets of keys.  Unfortunately it takes up a whole sheet of plastic.

Future Concepts

Moving forward, I want to find a way to eliminate all of the unnecessary material in all 32 of those vertical supports.  A bar or two mounted along the path of the key mounts could allow me to build much smaller plastic mounts for each key.  Look forward to another post with more designs, and watch my friend’s blogs for updates on their portions of the project!

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