Difference between revisions of "RC08-Chipper"

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[[Category: RoboCup]]
 
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[[Category:2007-2008]]]

Revision as of 21:56, 18 July 2018

This page contains the information and documentation of the 2008 chipper system

Robocup 2008 Mechanical

Assembly Structure

PART NAME PART NUMBER QUANTITY
Chipper Plate RC-2008-06-01 2
Left Arm RC-2008-06-02 2
Right Arm RC-2008-06-03 1
Chipper Hinge Shaft RC-2008-06-04 2
8-32 Lock Nut RC-2008-06-05 2
4-40 x 1/4 Screw RC-2008-06-06 2
8-32 Socket Cap Set Screw RC-2008-06-07 2
8-32 x 3/8 Hex Standoff RC-2008-06-08 2
8-32 Connecting Rod RC-2008-06-09 1

Parts & Components

Solenoid

Vendor: SolenoidCity


  • Electrical specification
    • 300 Volts
    • operates at 10% duty cycle


Plates

Chipper Plate
Vendor: McMaster-Carr
Part No.: 8885K13
Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
Cost: $21.73
  • Plate that makes contact with the ball
  • Material is same and shared with Omniwheel plates


Link
Vendor: McMaster-Carr
Part No.: 8885K13
Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
Cost: $21.73
  • Connects solenoid to the chipper assembly
  • Material is same and shared with Omniwheel plates and chipper plate
Solenoid Mounting Arms
Vendor: McMaster-Carr
Part No.: 8885K13
Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
Cost: $21.73
  • Holds solenoid stationary to robot
  • Material is same and shared with Omniwheel plates

Standoffs

8-32 x 3/8" Hex Standoff
Vendor: McMaster-Carr
Part No.: 91780A194
Description: Aluminum Female Threaded Hex Standoff 1/4" Hex, 3/8" Length, 8-32 Screw Size
Cost: $.34
  • Standoffs connecting the two chipper arms

Fasteners

6-32 x 1/4" socket cap screw
Vendor: McMaster-Carr
Part No.: 92220A141
Description: 6-32 x 1/4" steel, low profile, socket cap screw
Cost: $7.22 for 25
  • Connects the swing and hex standoff
6-32 x 3/4" socket cap screw
Vendor: McMaster-Carr
Part No.: 93615A217
Description: 6-32 x 3/4" 18-8 stainless steel, low profile, socket cap screw
Cost: $12.72 for 25
  • Connects the swing, motor plate, and hex standoff
8-32 Lock Nut
Vendor: McMaster-Carr
Part No.: 90633A009
Description: Steel Hex Nylon-Insert Locknut, 8-32 Screw Size, 11/32" W, 11/64" H
Cost: $2.21 each - STOCK
  • Constrains the dribbler and hinge shafts
4-40 Set Screw
Vendor: McMaster-Carr
Part No.: 91375A105
Description: Alloy Steel Cup Point Socket Set Screw 4-40 Thread, 3/16" Length
Cost: $7.99 for pack of 100
  • Pins dribbler roller to the dribbler shaft

Shaft

Chipper Hinge Shaft
Vendor: McMaster-Carr
Part No.: 8116K3
Description: A2 Tool Steel Tight-Tolerance Metric Rod 4 mm Diameter, 3' Length
Cost: $6.10
  • Pivot point of chipper
8-32 Connecting Rod
Vendor: McMaster-Carr
Part No.: 8116K3
Description: A2 Tool Steel Tight-Tolerance Metric Rod 4 mm Diameter, 3' Length
Cost: $6.10
  • Shaft for the links to connect solenoid to chipper


Other

Mounting block
Vendor: McMaster-Carr
Part No.: 3511T11
Description: Alloy 6061 Aluminum Ground Flat Stock .250" Thick, 6" X 6" Size
Cost: $45.44 each - STOCK
  • Connects entire dribbler assembly to the robot
4mm snap thrust bearing
Vendor: McMaster-Carr
Part No.: 7817K33
Description: Metric Nylon Snap-in Thrust Bearing for 4mm Shaft Dia, 1.45-2.34 mm Sheet Metal Thick
Cost: $1.32 each
  • supports dribbler shaft in the swing
3/8" Washer
Vendor: McMaster-Carr
Part No.: 93286A009
Description: Aluminum washer 3/8" OD,.175" ID, 1/32" thick
Cost: $3.52 for 100
  • Washer between the swing and hex standoff
Neoprene Rubber Tube
Vendor: McMaster-Carr
Part No.: 7505K86
Description: Ultra-Flex Neoprene Rubber Heat-Shrink Tubing 3/4" Expanded ID, 3/8" Shrunken ID,
Cost: $8.97
  • Roller and dribbler gear spin on dribbler shaft
  • Material is shared with the hinge shaft

Calculations

Torsion Spring
  • Analysis was done using the Work-Energy Principle with the assumption that the only work done is from the torsion spring and gravity. Because the dribbler assembly swings and has zero velocity at both positions, only the kinetic energy of the ball was used, at its maximum value of 10 m/s
Roller Speed
  • Gears were selected for a gear ratio lower than 2007. The 2008 ratio is 1.5. This was with the hope of having more torque available for the roller to grip the ball.

Notes

  • 4mm steel shaft chosen to increase strength to prevent bending of dribbler shaft when hit with a ball
  • roller diameter - .5"
  • dribbler shaft still slides free in between two snap-in thrust bearings and can be removed to allow the roller to be changed out]