RC08Omni

As part of the RoboCup 2008 Mechanical, the Omni Wheels allow the robots to move in any direction at anytime.

2008 RoboJackets RoboCup Omni Wheel

Materials

• Body
  1. Aluminum 7075
     • 1/2"
     • 1/16"
• Rollers
  1. Neoprene O-Rings
     • McMaster: Neoprene O-Ring AS568A Dash Number 012 (94115K012)
       • Pks of 100 for $2.87
       • Total Needed = (15*4*5)/100 = 3 + 1 = 4pks
  2. Aluminum 7075
     • 1/8"

Assembly Structure

Parts List

1. 15 - Rollers (RC-2008-01-00)
   1. 1 - O-Ring (RC-2008-01-01)
   2. 1 - Roller Hub (RC-2008-01-02)
2. 1 - Wheel Body (RC-2008-02-01)
3. 1 - Plate (RC-2008-02-02)
4. 1 - Ring / Axel (RC-2008-02-03)
5. 3 - 6-32 1/4" Long (RC-2008-07-04)

Instructions

1. Place 15 rollers on wire axle.
2. Bend to circular shape.
3. Drop in omni body.
4. Place omni plate on omni body.
5. Fasten using RC-2008-07-04

Parts & Components

Amounts are based on per robot. Materials are in sizes for prototyping not lowest cost per amount.

Stock

Plate - Wheel Plate

Vendor - McMaster-Carr

Part No. - 8885K13

Cost - $21.63

Description - Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"

Plate - Wheel Body

Vendor - McMaster-Carr

Part No. - 9037K21

Cost - $158.77

Description - Alloy 7075 Aluminum Sheet .500" Thick, 12" X 12"

Note: will look at thinner and optimize sheet size to a per robot amount

Shaft - Rollers

Vendor - McMaster-Carr

Part No. - 9063K243

Cost - $17.48

Description - Alloy 7075 Aluminum Precision Ground Rod 1/8" Diameter, 3' Length

Note: Usually ships within 2 weeks.

Fasteners

6-32 Low Head Socket Cap Screw

Vendor - McMaster-Carr

Part No. - 92220A141

Cost - $7.42 (packs of 25)

Description - Alloy Steel Low Head Socket Cap Screw 6-32 Thread, 1/4" Length

3/16" Dowel Pin

Vendor - MSC

Part No. - 88231758

Cost - $43.08 (per 100)

Description - Precision Ground Dowel Pins - Stainless Steel Type: Dowel Pin Diameter: 3/16 Overall Length: 1/4 Material: Stainless Steel - 416 SS Finish/Coating: Bright

Other

O-Ring (option 1)

Vendor - McMaster-Carr

Part No. - 94115K012

Cost - $2.87 (Pks of 100)

Quantity -

Description - Neoprene O-Ring AS568A Dash Number 012

O-Ring (option 2)

Vendor - McMaster-Carr

Part No. - 90025K137

Cost - $9.70 (Pks 100)

Quantity -

Description - Double Seal Buna-N O-Ring AS568A Dash Number 012

Axel / Wire

Vendor - McMaster-Carr

Part No. - 9666K69

Cost - $2.93

Description - 1080-1090 Carbon Steel Wire .059" Diameter, 1/4-lb Coil, 27' Coil

Fabrication

Omni Plates

Primary - Water Jetting (Outsourced)

Notes

Alignment holes will need to be reamed out.

Omni Bodies

Primary - Milling (Outsourced)

Notes -

Hex broaching

Press fitting in dowel pins.

Omni Rollers

Primary - Turning / Lathing (Outsourced)

Notes

We will apply o-rings.

Cost Estimates

1. Rollers - $0.42 x 15 = $6.30
2. Body - $4.00
3. O-rings - $0.03 x 15 = $0.45
4. Plate -
5. Fasteners - $0.30 x 3 = $0.90

Total - $11.65 (missing plate)

Note - Shipping is included in per unit cost.

Action Log

1. 12/04/2007 - RC-2008-PO-02 - Purchase Order for Omni Roller Hub Samples (Option A & B).
2. 12/14/2007 - RC-2008-PO-01 - Purchase Order for Omni Body Prototypes.
3. 12/28/2007 - Fabrication of Omni Plates completed.
4. 12/28/2007 - Full omni prototype completed.

   Notes - Very hard to get axle wire in to omni bodies must find new material.

5. 12/28/2007 - Roller Option A revised and selected for prototype set.

   Notes - Option B (square) is cheaper and requires a costs analysis change in dimension and different roller material may be required.

6. 12/29/2007 - RC-2008-PO-03 - Purchase Order for Omni Roller Hub (Rev 2).
7. 12/31/2007 - Looking at 8867K25, 9495K92 for alternate wire.
8. 01/29/2007 - Keeping original wire.
9. 03/05/2007 - Omni rollers finalized.
10. 03/08/2008 - Omni rollers sent out. (20 cents each)
11. 03/17/2008 - Investigating the use dowel pins to cut down on machining costs.
12. 03/30/2008 - Designs for body are finalized and sent out to supplier.

    Notes - Dowel / locating pins, relaxing tolerances, a new supplier, and hex broaching our selves have brought down the machining cost to around $4 per body (prototype $53).

13. 04/13/2008 - Fleet rollers arrive and are fitted with o-rings.
14. 05/14/2008 - Fleet bodies arrive, are hex'd, and have locating pins pressed in.

    Notes - A few were damaged in process a fitting for press was made, and replacements ordered.