RoboJackets Wiki - User contributions [en]

RC08Chassis

2008-05-16T22:12:12Z

Jason k:

As part of the [[RoboCupMechanical|RoboCup 2008 Mechanical]], this is the skeleton of the robots everything attaches to it.

==Assembly Structure==
===Parts List===
# 2 - Drive Module (RC-2008-03-00)
# 2 - Drive Module Mirror (RC-2008-03-00-M)
# 1 - Dribbler (RC-2008-04-00)
# 1 - Kicker / Chipper (RC-2008-05-00)
# 1 - Bottom Plate (RC-2008-07-01)
# 1 - Electrical Plate (RC-2008-07-03)
# 4 - 2 1/2" Long Hex Standoffs (RC-2008-07-02)
# 10 - 6-32 1/4" Long (RC-2008-07-04)
# 8 - 8-32 3/8"Long (RC-2008-03-13)
# 8 - 8-32 Nylon Lock Nuts (RC-2008-07-05)
# 1 - Electrical Board (RC-2008-07-06)

===Configuration Notes===
# Due to space constraints drive modules are not orthogonal. They are X degrees off inward. (See drawings)

==Parts & Components==
===Stock===
=====Top Plates=====
:Vendor - McMaster-Carr
:Part No. - 89015K39
:Cost - $43.33 Each
:Description - Alloy 6061 Aluminum Sheet .063" Thick, 24" X 24"

=====Bottom Plate=====
:Vendor - McMaster-Carr
:Part No. - 8885K18
:Cost - $35.62 Each
:Description - Alloy 7075 Aluminum Sheet .050" Thick, 12" X 24"

=====Antenna Supporting Plate=====
:Vendor - McMaster-Carr
:Part No. - 8574K38
:Cost - $6.29 Each
:Description - Polycarbonate Sheet 1/16" Thick, 12" X 24", Clear

===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

=====8-32 Low Head Socket Cap Screw=====
:Vendor - McMaster-Carr
:Part No. - 92220A152
:Cost - $11.60 (Packs of 100)
:Description - Alloy Steel Low Head Socket Cap Screw 8-32 Thread, 3/8" Length

=====8-32 Nylon Lock Nut=====
:Vendor - McMaster-Carr
:Part No. - 90633A009
:Cost - $2.21 (Packs of 100)
:Description - Grade 2 Hex Thin (Jam) Nylon-Insert Locknut Zinc-Pltd Steel, 8-32 Screw Size, 11/32" W, 11/64" H

===Other===
=====1/4" Hex Standoff 2.5"=====
:Vendor - DigiKey
:Part No. - 1825K-ND
:Cost - $1.14 Each (must order min 10)
:Description - STANDOFF HEX 6-32THR 2.5"L ALUM

=====1/4" Hex Standoff 0.25"=====
:Vendor - DigiKey
:Part No. - 8717K-ND
:Cost - $0.394 Each (must order min 10)
:Description - STANDOFF HEX M/F 6-32 .250" ALUM

=====1/4" Hex Standoff 0.25"=====
:Vendor - DigiKey
:Part No. - 2208K-ND
:Cost - $0.307 Each (must order min 10)
:Description - STANDOFF HEX 6-32THR .250" ALUM

=====1/4" Hex Standoff 0.75"=====
:Vendor - DigiKey
:Part No. - 8416K-ND
:Cost - $0.471 Each (must order min 10)
:Description - STANDOFF HEX 6-32 0.75"L ALUM MALE FEMALE

=====1/4" Hex Standoff 1.25"=====
:Vendor - DigiKey
:Part No. - 1818K-ND
:Cost - $0.776 Each (must order min 10)
:Description - STANDOFF HEX 6-32THR 1.25"L ALUM

=====6-32 Low Head Socket Cap Screw=====
:Vendor - McMaster-Carr
:Part No. - 92220A144
:Cost - $8.75 (Packs of 25)
:Description - Alloy Steel Low Head Socket Cap Screw 6-32 Thread, 5/8" Length

===Shell===
:Vendor - McMaster-Carr
:Part No. - 91780A209
:Cost - $0.44
:Description - Aluminum Female Threaded Hex Standoff 1/4" Hex, 7/8" Length, 6-32 Screw Size

:Vendor - McMaster-Carr
:Part No. - 91780A339
:Cost - $0.93
:Description - Aluminum Female Threaded Hex Standoff 1/4" Hex, 2" Length, 6-32 Screw Size

:Vendor - McMaster-Carr
:Part No. - 91565A315
:Cost - %6.58 (Pack of 100)
:Description - Plain Steel Fully Threaded Stud 6-32 Thread, 1/2" Length

===Action Log===
# 01/03/2008 - Bottom plate prototype completed.
# 02/15/2008 - Top plate prototype completed.
# 03/18/2008 - Ground clearance concerns have prompted investigating into correcting.
#: Notes - Possible fixes, larger omni wheels, moving wheels down.
# 03/30/2008 - Moving wheels down has been selected for fixing ground clearance.
# 04/08/2008 - Standoffs for the electrical boards up to the shell have been found and overall height for the robot has been finalized.
# 04/10/2008 - We have decided to go with pressing for creating space for output gears on the bottom plate. This allows us to move the wheels down for additional ground clearance.
# 04/10/2008 - Cutouts for motor wires need to be moved in some to allow for more slack and connection with electrical board.
# 04/15/2008 - Die for stamping bottom plate gear allowances has been made and the process produces successful results.
# 04/22/2008 - Bigger cutouts for drive motor cabling, addition of antenna support plate, standoff change.

RC08-Dribbler

2008-05-05T02:19:39Z

Jason k: /* Dimensional Analysis */

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

[[RobocupMechanical|Robocup 2008 Mechanical]]

==Assembly Structure==
{| border="1" cellpadding="2"
!width="225"|PART NAME
!width="100"|PART NUMBER
!width="50"|QUANTITY
|-
|Mounting Block || RC-2008-04-01 || 2
|-
|-
|Swing|| RC-2008-04-02 || 2
|-
|-
|Motor Plate || RC-2008-04-03 || 1
|-
|-
|Standoff || RC-2008-04-04 || 2
|-
|-
|Hinge Shaft || RC-2008-04-05 || 1
|-
|-
|8-32 Lock Nut || RC-2008-04-06 || 4
|-
|-
|2" Hex Standoff|| RC-2008-04-07 || 1
|-
|-
|Dribbler Motor || RC-2008-04-08 || 1
|-
|-
|M2x5 Screw || RC-2008-04-09 || 2
|-
|-
|Dribbler Motor Gear || RC-2008-04-10 || 1
|-
|-
|6-32 x 3/4 Screw || RC-2008-04-11 || 1
|-
|-
|Cross Plate || RC-2008-04-12 || 1
|-
|-
|4mm Snap Bearing|| RC-2008-04-13 || 2
|-
|-
|Dribbler Shaft || RC-2008-04-14 || 1
|-
|-
|Dribbler Roller || RC-2008-04-15 || 1
|-
|-
|Dribbler Roller Gear || RC-2008-04-16 || 1
|-
|-
|Left Torsion Spring || RC-2008-04-17 || 1
|-
|-
|Right Torsion Spring || RC-2008-04-18 || 1
|-
|-
|6-32 x 1/4 Screw || RC-2008-04-19 || 1
|-
|-
|3/8" Washer || RC-2008-04-20 || 1
|-
|-
|Neoprene Rubber Tube || RC-2008-04-21 || 1
|-
|-
|4-40 Set Screw|| RC-2008-04-22||1
|-
|}

==Parts & Components==
===Motor===
Fleet motor from Maxon
*Part no: 266521 with attached gear head 118184.
*5.4 gear reduction
*cost: $146.20 each
*[http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_154_e.pdf Motor Data Sheet]
*[http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_215_e.pdf Gearhead Data Sheet]

Vendor: MicroMo
* Motor: 12V DC brushless servo motor #E-1628B
**$147.10 each
* Planetary gearhead: #E-167 gear reduction: 14
* Complete assembly 1628-V-0003
Cost: $200.40 each

* [http://www.micromo.com/ MicroMo]
* [http://www.micromo.com/uploadpk/e_1628B_MIN.pdf Motor Data Sheet]
* [http://www.micromo.com/uploadpk/e_167_MIN.pdf Gearhead Data Sheet]

* Electrical specification
** 12 Volts
** must have position or speed encoders
** brushless DC

*Maxon motor, the same CMU uses, was chosen for the fleet. This was based on 4wk shorter lead time, $60 cheaper per motor, and significantly greater performance as can be seen from the figures generated by a Matlab script
[[image:motor_comparison.jpg|800 px|Dribbler motor comparison]]

===Gears===
=====Motor gear=====
:Vendor: SDP/SI
:Part No.: A 1B 2MYK05035
:Description: Module 0.5, 35 Teeth, 20° Pressure Angle, Brass Gear with set screw, 3mm bore, 17.5mm PD
:Cost: $7.47
:Drawing:[https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Motor Gear Spec Sheet]
*Connects directly to output of motor and powers dribbler roller

=====Roller gear=====
:Vendor: SDP/SI
:Part No.: A 1B 2MYK05025
:Description: Module 0.5, 25 Teeth, 20° Pressure Angle, Brass Gear with set screw, 3mm bore, 12.5mm PD
:Cost: $6.03
:Drawing:[https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Dribbler Gear Spec Sheet]
*Roller gear bore must be reamed out to 4mm
*Powers the dribbler roller - is recessed into the roller itself

===Plates===
=====Swing=====
:Vendor: McMaster-Carr
:Part No.: 8885K13
:Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
:Cost: $21.73
*Contains the roller shaft, the motor mounts, spacers, and hinge shafts
*Material is same and shared with Omniwheel plates
*Left and right swings are identical

=====Motor plate=====
:Vendor: McMaster-Carr
:Part No.: 8885K13
:Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
:Cost: $21.73
*Supports motor and connects to the 2 spacers in assembly
*Material is same and shared with Omniwheel plates

=====Cross Plate=====
:Vendor: McMaster-Carr
:Part No.: 8885K13
:Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
:Cost: $21.73
*Connects both mounting blocks and provides mechanical limitation for swing and torsion springs
*Material is same and shared with Omniwheel plates

===Standoffs===
=====Standoff=====
:Vendor: McMaster-Carr
:Part No.: 9062K271
:Description: Alloy 6061 Aluminum Precision-Ground Rod 5/16" Diameter, 1' Length
:Cost: $9.10
*Standoff between swing and motor plate

=====2" Hex Standoff=====
:Vendor: McMaster-Carr
:Part No.: 91780A339
:Description: Aluminum Female Threaded Hex Standoff 1/4" Hex, 2" Length, 6-32 Screw Size
:Cost: $.88
*Hex standoff between motor plate and swing
*Both torsion springs anchor into the standoff

===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===
=====Hinge shaft=====
:Vendor: McMaster-Carr
:Part No.: 8116K3
:Description: A2 Tool Steel Tight-Tolerance Metric Rod 4 mm Diameter, 3' Length
:Cost: $6.10
*Joint between swings and mounting blocks

=====Dribbler shaft=====
:Vendor: McMaster-Carr
:Part No.: 8116K3
:Description: A2 Tool Steel Tight-Tolerance Metric Rod 4 mm Diameter, 3' Length
:Cost: $6.10
*Roller and dribbler gear spin on dribbler shaft
*Material is shared with the hinge shaft

===Springs===
=====Left Torsion Spring=====
:Vendor: McMaster-Carr
:Part No.: 9271K35
:Description: 1.375 lbf-in of torque. Music Wire Torsion Spring 90 Deg Angle, .309" Coil OD, .040" Wire, Cw/Lh, Packs of 6
:Cost: $6.56 for 6
*Left hand wound torsion spring
*Rests on hinge shaft and provides cushioning for ball impact

=====Right Torsion Spring=====
:Vendor: McMaster-Carr
:Part No.: 9271K33
:Description: 1.375 lbf-in of torque. Music Wire Torsion Spring 90 Deg Angle, .309" Coil OD, .040" Wire, Cw/Rh, Packs of 6
:Cost: $6.56 for 6
*Right hand wound torsion spring
*Rests on hinge shaft and provides cushioning for ball impact

===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.

=====Dimensional Analysis=====
* Using the Buckingham Pi theorem, an unknown function expressing the moment the dribbler roller puts on the ball based on other parameters was developed.
* The inputs to this function can now guide the testing plan for the dribbler
* The mom<math>f(mu)</math>
[[Image:Dribblerdimension.png]]

==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
*several 4mm holes were widened to .170" holes to allow easy assembly with the 8-32 threaded shaft
*it proved very difficult to even squeeze 4mm shaft through the thrust bearings
*due to unknown errors a few addtional washers were placed in the assembly
*on the left arm a small cut was created to allow the motor shaft to protrude
*a new motor plate was created and fits flush to the motor
*it was found when the original motor plate was attached and fastended, it would add a high amount of friction and actually stalled the motor
*a big issue is that the 2 dribbler arms must be connected around either the back or the front - and not rotate independently
*this independent rotation swivels the motor around, putting more stress and wear on the gears, or makes the gears not even mesh
*the small standoff closest to the motor was replaced with a hex standoff, as it would hit the motor gear slightly if the motor was pushed up a bit
*a 4mm die will be purchased to thread the shafts, preventing boring of 4mm holes

==Changes from Prototype==
* a standoff now near the roller itself to provide structural stability, connect the two formerly independent swing arms, and protect the motor from ball impacts
* clinch nuts will be used to anchor the assembly to the robot, making it much easier to remove the dribbler assembly
* the motor mount plate now connects to the hinge axis, the motor, and the front standoff
* the 4mm hinge and roller shafts will be threaded to fit 4mm hex nuts
* the gear ratio between the motor and roller has increased from 1:1.4 to 1:1.75
* the dribbler roller diameter has increased from .5" to 5/8"

==Dribbler bar prototypes==
*shaft diameter on ends of bar - 3mm
*maximum diameter of dribbler - .75"
*the dribbler bar prototypes will be lathed and done coated with neoprene heat shrink
[[image:dribblerprototype.png|500 px|Dribbler bar prototype drawing]]

===dribbler bar prototypes===
*3/4" diameter aluminum bar stock
**$8.34
**McMaster part number 6750K181
*3mm diameter aluminum bar stock
**$6.94
**McMaster part number 1681T21
*3/4" neoprene heat shrink
**pack of 5 for $8.97
**McMaster part number 7505K86
*3mm e-clips
**pack of 100 for $3.03
**McMaster part number 98543A101

==2007 Dribbler==
===Drive gear===
*attached to the motor
*SDP/SI A-1B-2MYK05045 [https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Data sheet]
*45 teeth, 3mm bore, 22.5mm pitch diameter
===Dribbler gear===
*attached to the roller. This is done by pressing having a set screw in the gear interfere with the roller. Both the gear and roller are free to spin on the shaft, which permitting easy change.
*SDP/SI A-1B-2MYKO5020H [https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Data sheet]
*20 teeth, 3mm bore, 10mm pitch diameter

*gear ratio from motor to drilbber = 2.25
===Motor===
*15.9mm diameter, 3mm output shaft

==Specs from CMU==
*Dribbler motor gear from SDP-SI: S10T05M042A0303 Module 0.5, 42 Teeth, 20° Pressure Angle , 2024 Aluminum alloy Gear
*Dribbler bar gear from SDP-SI: S10T05M028A0305 Module 0.5, 28 Teeth, 20° Pressure Angle , 2024 Aluminum alloy Gear
*spur gear reduction 1:1.5
*Dribbler Motor - Maxon
**266521
**http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_154_e.pdf
**nominal speed 28200 rpm

*Gearhead
**118184 - Maxon
**http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_215_e.pdf
**reduction 5.4:1

*nominal dribbler bar speed = 28200/5.4*1.5 = 7833 RPM. It is, of course, adjustable by software.

File:Dribblerdimension.png

2008-05-05T02:16:03Z

Jason k: Dimensional analysis of the dribbler system.

Dimensional analysis of the dribbler system.

RC08-Dribbler

2008-05-05T02:12:45Z

Jason k:

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

[[RobocupMechanical|Robocup 2008 Mechanical]]

==Assembly Structure==
{| border="1" cellpadding="2"
!width="225"|PART NAME
!width="100"|PART NUMBER
!width="50"|QUANTITY
|-
|Mounting Block || RC-2008-04-01 || 2
|-
|-
|Swing|| RC-2008-04-02 || 2
|-
|-
|Motor Plate || RC-2008-04-03 || 1
|-
|-
|Standoff || RC-2008-04-04 || 2
|-
|-
|Hinge Shaft || RC-2008-04-05 || 1
|-
|-
|8-32 Lock Nut || RC-2008-04-06 || 4
|-
|-
|2" Hex Standoff|| RC-2008-04-07 || 1
|-
|-
|Dribbler Motor || RC-2008-04-08 || 1
|-
|-
|M2x5 Screw || RC-2008-04-09 || 2
|-
|-
|Dribbler Motor Gear || RC-2008-04-10 || 1
|-
|-
|6-32 x 3/4 Screw || RC-2008-04-11 || 1
|-
|-
|Cross Plate || RC-2008-04-12 || 1
|-
|-
|4mm Snap Bearing|| RC-2008-04-13 || 2
|-
|-
|Dribbler Shaft || RC-2008-04-14 || 1
|-
|-
|Dribbler Roller || RC-2008-04-15 || 1
|-
|-
|Dribbler Roller Gear || RC-2008-04-16 || 1
|-
|-
|Left Torsion Spring || RC-2008-04-17 || 1
|-
|-
|Right Torsion Spring || RC-2008-04-18 || 1
|-
|-
|6-32 x 1/4 Screw || RC-2008-04-19 || 1
|-
|-
|3/8" Washer || RC-2008-04-20 || 1
|-
|-
|Neoprene Rubber Tube || RC-2008-04-21 || 1
|-
|-
|4-40 Set Screw|| RC-2008-04-22||1
|-
|}

==Parts & Components==
===Motor===
Fleet motor from Maxon
*Part no: 266521 with attached gear head 118184.
*5.4 gear reduction
*cost: $146.20 each
*[http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_154_e.pdf Motor Data Sheet]
*[http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_215_e.pdf Gearhead Data Sheet]

Vendor: MicroMo
* Motor: 12V DC brushless servo motor #E-1628B
**$147.10 each
* Planetary gearhead: #E-167 gear reduction: 14
* Complete assembly 1628-V-0003
Cost: $200.40 each

* [http://www.micromo.com/ MicroMo]
* [http://www.micromo.com/uploadpk/e_1628B_MIN.pdf Motor Data Sheet]
* [http://www.micromo.com/uploadpk/e_167_MIN.pdf Gearhead Data Sheet]

* Electrical specification
** 12 Volts
** must have position or speed encoders
** brushless DC

*Maxon motor, the same CMU uses, was chosen for the fleet. This was based on 4wk shorter lead time, $60 cheaper per motor, and significantly greater performance as can be seen from the figures generated by a Matlab script
[[image:motor_comparison.jpg|800 px|Dribbler motor comparison]]

===Gears===
=====Motor gear=====
:Vendor: SDP/SI
:Part No.: A 1B 2MYK05035
:Description: Module 0.5, 35 Teeth, 20° Pressure Angle, Brass Gear with set screw, 3mm bore, 17.5mm PD
:Cost: $7.47
:Drawing:[https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Motor Gear Spec Sheet]
*Connects directly to output of motor and powers dribbler roller

=====Roller gear=====
:Vendor: SDP/SI
:Part No.: A 1B 2MYK05025
:Description: Module 0.5, 25 Teeth, 20° Pressure Angle, Brass Gear with set screw, 3mm bore, 12.5mm PD
:Cost: $6.03
:Drawing:[https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Dribbler Gear Spec Sheet]
*Roller gear bore must be reamed out to 4mm
*Powers the dribbler roller - is recessed into the roller itself

===Plates===
=====Swing=====
:Vendor: McMaster-Carr
:Part No.: 8885K13
:Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
:Cost: $21.73
*Contains the roller shaft, the motor mounts, spacers, and hinge shafts
*Material is same and shared with Omniwheel plates
*Left and right swings are identical

=====Motor plate=====
:Vendor: McMaster-Carr
:Part No.: 8885K13
:Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
:Cost: $21.73
*Supports motor and connects to the 2 spacers in assembly
*Material is same and shared with Omniwheel plates

=====Cross Plate=====
:Vendor: McMaster-Carr
:Part No.: 8885K13
:Description: Alloy 7075 Aluminum Sheet .063" Thick, 12" X 12"
:Cost: $21.73
*Connects both mounting blocks and provides mechanical limitation for swing and torsion springs
*Material is same and shared with Omniwheel plates

===Standoffs===
=====Standoff=====
:Vendor: McMaster-Carr
:Part No.: 9062K271
:Description: Alloy 6061 Aluminum Precision-Ground Rod 5/16" Diameter, 1' Length
:Cost: $9.10
*Standoff between swing and motor plate

=====2" Hex Standoff=====
:Vendor: McMaster-Carr
:Part No.: 91780A339
:Description: Aluminum Female Threaded Hex Standoff 1/4" Hex, 2" Length, 6-32 Screw Size
:Cost: $.88
*Hex standoff between motor plate and swing
*Both torsion springs anchor into the standoff

===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===
=====Hinge shaft=====
:Vendor: McMaster-Carr
:Part No.: 8116K3
:Description: A2 Tool Steel Tight-Tolerance Metric Rod 4 mm Diameter, 3' Length
:Cost: $6.10
*Joint between swings and mounting blocks

=====Dribbler shaft=====
:Vendor: McMaster-Carr
:Part No.: 8116K3
:Description: A2 Tool Steel Tight-Tolerance Metric Rod 4 mm Diameter, 3' Length
:Cost: $6.10
*Roller and dribbler gear spin on dribbler shaft
*Material is shared with the hinge shaft

===Springs===
=====Left Torsion Spring=====
:Vendor: McMaster-Carr
:Part No.: 9271K35
:Description: 1.375 lbf-in of torque. Music Wire Torsion Spring 90 Deg Angle, .309" Coil OD, .040" Wire, Cw/Lh, Packs of 6
:Cost: $6.56 for 6
*Left hand wound torsion spring
*Rests on hinge shaft and provides cushioning for ball impact

=====Right Torsion Spring=====
:Vendor: McMaster-Carr
:Part No.: 9271K33
:Description: 1.375 lbf-in of torque. Music Wire Torsion Spring 90 Deg Angle, .309" Coil OD, .040" Wire, Cw/Rh, Packs of 6
:Cost: $6.56 for 6
*Right hand wound torsion spring
*Rests on hinge shaft and provides cushioning for ball impact

===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.

=====Dimensional Analysis=====
* Using the Buckingham Pi theorem, an unknown function expressing the moment the dribbler roller puts on the ball based on other parameters was developed.
* The inputs to this function can now guide the testing plan for the dribbler

==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
*several 4mm holes were widened to .170" holes to allow easy assembly with the 8-32 threaded shaft
*it proved very difficult to even squeeze 4mm shaft through the thrust bearings
*due to unknown errors a few addtional washers were placed in the assembly
*on the left arm a small cut was created to allow the motor shaft to protrude
*a new motor plate was created and fits flush to the motor
*it was found when the original motor plate was attached and fastended, it would add a high amount of friction and actually stalled the motor
*a big issue is that the 2 dribbler arms must be connected around either the back or the front - and not rotate independently
*this independent rotation swivels the motor around, putting more stress and wear on the gears, or makes the gears not even mesh
*the small standoff closest to the motor was replaced with a hex standoff, as it would hit the motor gear slightly if the motor was pushed up a bit
*a 4mm die will be purchased to thread the shafts, preventing boring of 4mm holes

==Changes from Prototype==
* a standoff now near the roller itself to provide structural stability, connect the two formerly independent swing arms, and protect the motor from ball impacts
* clinch nuts will be used to anchor the assembly to the robot, making it much easier to remove the dribbler assembly
* the motor mount plate now connects to the hinge axis, the motor, and the front standoff
* the 4mm hinge and roller shafts will be threaded to fit 4mm hex nuts
* the gear ratio between the motor and roller has increased from 1:1.4 to 1:1.75
* the dribbler roller diameter has increased from .5" to 5/8"

==Dribbler bar prototypes==
*shaft diameter on ends of bar - 3mm
*maximum diameter of dribbler - .75"
*the dribbler bar prototypes will be lathed and done coated with neoprene heat shrink
[[image:dribblerprototype.png|500 px|Dribbler bar prototype drawing]]

===dribbler bar prototypes===
*3/4" diameter aluminum bar stock
**$8.34
**McMaster part number 6750K181
*3mm diameter aluminum bar stock
**$6.94
**McMaster part number 1681T21
*3/4" neoprene heat shrink
**pack of 5 for $8.97
**McMaster part number 7505K86
*3mm e-clips
**pack of 100 for $3.03
**McMaster part number 98543A101

==2007 Dribbler==
===Drive gear===
*attached to the motor
*SDP/SI A-1B-2MYK05045 [https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Data sheet]
*45 teeth, 3mm bore, 22.5mm pitch diameter
===Dribbler gear===
*attached to the roller. This is done by pressing having a set screw in the gear interfere with the roller. Both the gear and roller are free to spin on the shaft, which permitting easy change.
*SDP/SI A-1B-2MYKO5020H [https://sdp-si.com/eStore/..%5Css%5CPDF%5CSSUM7025.PDF Data sheet]
*20 teeth, 3mm bore, 10mm pitch diameter

*gear ratio from motor to drilbber = 2.25
===Motor===
*15.9mm diameter, 3mm output shaft

==Specs from CMU==
*Dribbler motor gear from SDP-SI: S10T05M042A0303 Module 0.5, 42 Teeth, 20° Pressure Angle , 2024 Aluminum alloy Gear
*Dribbler bar gear from SDP-SI: S10T05M028A0305 Module 0.5, 28 Teeth, 20° Pressure Angle , 2024 Aluminum alloy Gear
*spur gear reduction 1:1.5
*Dribbler Motor - Maxon
**266521
**http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_154_e.pdf
**nominal speed 28200 rpm

*Gearhead
**118184 - Maxon
**http://test.maxonmotor.com/docsx/Download/catalog_2007/Pdf/07_215_e.pdf
**reduction 5.4:1

*nominal dribbler bar speed = 28200/5.4*1.5 = 7833 RPM. It is, of course, adjustable by software.

2008-01-25T22:29:26Z

Jason k:

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

[[RobocupMechanical|Robocup 2008 Mechanical]]

==Assembly Structure==
{| border="1" cellpadding="2"
!width="225"|PART NAME
!width="100"|PART NUMBER
!width="50"|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
* .75" diameter, 1.5" long, pull type tubular solenoid, model number S-15-75
* Comes with 9/16" hex nut
* [http://www.solenoidcity.com/ SolenoidCity]
* [http://www.pdfdownload.org/pdf2html/pdf2html.php?url=http%3A%2F%2Fsolenoidcity.com%2Fsolenoid%2Ftubular%2Fs-15-75.pdf&images=yes Solenoid Data Sheet]

* 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

RoboCup Testing

2008-01-23T20:37:38Z

Jason k: /* Tests */

RoboCup Testing

2008-01-23T20:30:49Z

Jason k:

2008-01-22T17:45:44Z

Jason k:

RoboCup Testing

2008-01-22T17:45:21Z

Jason k:

Documentation and testing methods for evaluating different components and systems of the 2008 RoboCup Robots
*[[RoboCupMechanical | RoboCup Mechanical]]

==Dribbler==

====Trap ball====
* Ball speed- speed the ball can hit the without moving back. Use a spring and a speed trap to measure the speed.
* Ball angle- rotate the robot
* Rebound- distance the ball bounces back

# Hold ball
* Center time- measure time in seconds
* Climb ball- measure change in normal force on the measuring platform
* Pull force- angle of loss of contact. Measure what incline the measuring platform is required for the dribbler to lose contact
* Reverse speed- have the robot on a treadmill and measure when the ball comes lose
* Lateral speed- have the robot on the treadmill but have the dribbler facing tangential to the motion
* Rotational speed- rotate the speed of the carpet and see when the dribbler loses control

# Material Test
* Measure either the lifetime of the dribbler under continuous operation and visually inspect the dribbler.

==Kicker==
* Evaluate kicking capabilities, such as max speed reached
* Control speed- speed trap measuring velocity versus voltage
* Accuracy- impact test to measure where the ball impacts a wall
* Lifetime- how long does the kicker last both with a ball being hit and when there is no ball. Also measure changes in speed and accuracy over time.
* Frequency- how long between successive firings

==Chipper==
* Evaluate range capabilities of a chipper design
* Range- to where the ball lands
* Angle- accuracy to how close the ball lands
* Lifetime analysis same as kicker

==Shell==
* Maximum speed ball at different areas of the shell until it breaks

==Omni wheels==
* Test the reliablitity and effectiveness of the omniwheels for traction
* Traction- run the robot up an incline

2008-01-22T17:32:52Z

Jason k:

This page houses the current RoboCup Mechanical efforts. The 2007 efforts can be found [[RoboCupMechanical2007 | here]]. All development work will be done in Autodesk Inventor 2008. How to use Inventor and get it can be found on the [[How to Guide Inventor | Inventor How to Guide]]. Inventor is also available on our CAD Machines in Tin.

Mechanical team meets Tuesday 6-9pm with the general meeting at 7pm and 2-6pm on Sundays. More hours will be announced as deadlines approach.

[[RoboCup| RoboCup]]

[[Image:RC2008DevRender.jpg|thumb|right|A developement rendering of a 2008 RoboCup robot]]

==Systems==
* Drivetrain
** [[RC08Omni|Omni Wheels]]
** [[RoboCup Drive Motors/Gears|Motors/Gearing]]
** [[RC08Drive Module|Drive Module]]
* Integration
** [[RC08Shell|Shell]]
** [[RC08Chassis|Chassis]]
* Ball Control
** [[RC08-Dribbler|Dribbler]]
** [[RC08-Kicker|Kicker]]
** [[RC08-Chipper|Chipper]]
*[[RC08METestRig|Test Rig]]

==Schedule==
* deadline for completion of Everything Box - 11/30/07
* completion of ONE DRIVING, COMPLETE robot - 1/7/08

==Specifications==
* maximum robot weight - 1.8 kg
* ball speed after being kicked - 10 m/s
* dribbler bar speed - 8000 rpm
* compress time (time for dribbler to absorb ball's energy and compress) - .2 seconds
* no more than 20% of the ball's area (seen from top view) may be occupied by the robot - a critical Robocup SSL Rule
** see [[image:Ball sketch.PNG|250 px|Ball sketch]]

==Meetings==
*9/6/07 - Update for new members, organized testing plan and ideas
*9/13/07 - Organized most of the required tests into one device that will be designed starting on monday when we get CAD computer's back in the TIN.
*9/20/07 - The Test Rig aka "The Everything Box" is being designed and components spec-ed out. The hunt continutes for the dribbler motor.
*9/24/07 - Everything Box still being designed, would like to start ordering parts on Monday 10/3/07. Idea generation started on the dribbler system such as suspension and damping systems
*9/27/07 - Test Rig nearing completion. Concepts of ball control system discussed as well as the use of solenoids or some other actuator for the kicker
*10/1/07 - A cheap treadmill is being looked at for the testing rig. Conceptual planning is being done on the ball control system. Throughout the week, different ideas for the profile of the dribbler will be made on the lathe and then tested.
** the shaft output of the dribbler bar must be 3mm in diameter to fit in the gear of the current dribbler
*10/4/04 - Dribbler prototypes designed and parts are being ordered to make it. The dribbler motor was chosen and is being ordered as well. Work still continues on the kicker and chipper actuation. Lets work some over fall break! yah...!
*10/11/07 - Dribbler prototype drawings made. Ball control system still in discussion.
*10/15/07 - Everything Box design done, parts ordered tomorrow. Drive modules nearing completion.
*10/18/07 - Everything Box is under construction
*10/22/07 - Everything Box is under construction, other parts are being designed
*10/25/07 - Everything Box design complete and parts are being fabricated
*10/29/07 - Everything Box still being fabricated
*11/1/07 - No Robocup meeting due to the Virginia Tech football game
*11/4/07 - No Robocup meeting. Everyone busy.
*11/7/07 - Mechanical and electrical components for Everything Box being fabricated.
*11/26/07 - Everything Box is nearly complete, as are the electronics for it. Electronic controls are also nearly done for to control the new drive motors - giving the CS team a platform to use for testing. The machining of a few parts will be outsourced to different suppliers.
*11/29/07 - Remainder of parts made, as well as some drawings of parts
*12/2/07 - Everything Box is done, dribbler is nearly finished, drawings still continue to be made to posted for outsourcing
*12/17/07 - After a break for finals work resumes. Majority of parts ordered for the prototype, design nearly complete - still a bit of tweaking remains. Carbon fiber is being researched for shell.
*12/18/07 - McMaster order picked up. Kicker solenoid spec-ed out, documentation of design continues.
*12/19/07 - Spring for the dribbler was designed and selected. position of drive modules will be moved. CAM software tested and g-code created for both drive module plates.
*12/20/07 - Machining has begun with the drive module inner and outer plates. Roller prototypes for the ominwheels were received and are being evaluated.
*12/26/07 - Drive module plates completed. Machining begun, slowly, on the omniwheel plates.
*12/28/07 - Omniwheel plates are complete. The omniwheel bodies arrived and a full omniwheel was assembled - its beautiful. Revisions were made to the rollers based on the wheel and will be sent out. Drive electronics for the Everything Box are being assembled.
*12/30/07 - The everything box finally has speed control to it. Dribbler parts were machined.
*1/2/08 - Kicker solenoid was decided upon, preliminary cost analysis performed.
*1/8/08 - Chipper simulation continues but solution is just about found, machining started on output drive shafts.
*1/9/08 - Many parts recieved and an output shaft was turned on the lathe. A few other parts have been fabricated.
*1/15/08 - Drive shafts are done, solenoids have been ordered, alternate supplier was found for drive gears to get them sooner. A game controller was connected to computers to control 2007 robots.
*1/21/08 - All parts have been lathed. Heat shrink was used for the 2007 dribbler very effectively for qualification

==Documentation==

==Testing==
[[RoboCup Testing RoboCup| Testing]]

==Quick Notes==
* field area 5 meters x 3.5 meters
* max ball speed - 10 m/s
* ball diameter - 43 mm
* ball mass - 46 grams
* 1 rpm = .105 rad/s
* ball material - DuPont Surlyn Ionomer [http://www2.dupont.com/Surlyn/en_US/ Dupont's Surlyn Page]
* coefficient of static friction of golf ball on felt carpet - .66
** last two points from Cornell 2003 Mechanical Documentation

==Parts==
*[[RC08-Components|System Components and Bill of Materials]]
*[[RC08-Parts|Parts to Order]]

==Useful Links==
* [http://www.cis.cornell.edu/boom/2005/ProjectArchive/robocup/ Cornell Documents] (Look at 2003)

[[Category: RoboCup]] [[Category: 2008]]

* [ftp://ftp.itam.mx/pub/alfredo/PAPERS/SotoWeitzenfeld80LARS2006.pdf Eagle Knights Dribbler Testing]

[[Category: RoboCup]] [[Category: 2008]]

*[http://www.sdp-si.com/D220/D220cat.htm#T35 Mechanical Engineering Tips]

*[http://www.linuxcnc.org/handbook/gcode/g-code.html G-Code Tutorial]

*[http://robojackets.org/~circuitben/ Overhead camera footage from Robocup 2007 Championship Match]

*[http://www.drgears.com/gearterms/GearTermIndex.htm Dr. Gear - Gear Encyclopedia]

*[http://shtylman.com/robocup_resource/mechanical/CornellRoboCupMechanicalDocumentation2004.doc Cornell 2004 Mechanical Documentation]

*[http://pergatory.mit.edu/2.007/Resources/index.html#manufacturing MIT Design Handbook Index] (VERY GOOD)

*[http://thomasnet.com Global supplier and CAD drawing database]