Drivetrain Product

Drivetrain Design

The Techno Warriors Advanced have eight years of FTC experience designing, testing, and building drivetrains. The drivetrain is fully modeled in PTC Creo and the model is available on the team’s web page. A little drivetrain team history:
· In the summer of 2015 the team tested 7 different drivetrains to identify what was needed in a FTC drivetrain.
· The 2015-2016 season the game added a mountain to climb, during that season the team built 35 different drivetrains to climb the mountain.
· Over the summer of 2016 the team implemented a Failure Analysis process to identified several weaknesses in FTC robots and test innovations.
· The 2016-2017 season, TWA-1 was designed, tested and used the entire season (6 tournaments and countless community events). TWA-1 had no mechanical failures the entire season.
· This summer we updated the design to a production version and fully tested TWA-1.
Mary

Drawings


TWA-1 has three custom parts and a total of 529 parts from suppliers such as AndyMark Servo City 80/20 and Vex. --Owen


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Here is the completed TWA-1 --Owen


PTC Model of TWA-1


Prototype

During our summer we decide to make the best drivetrain and then sell it to other FTC teams, we refined our drivetrain from last year and built a prototype and ran it through many tests to prove it's one of the most consistent drivetrains we have ever built.
After that, we found the best materials, selected from top manufacturers and set to work making the final product. As we built it we took lots of pictures and wrote building instructions for people to use. It took most of the summer but we're done and proud to show off our new drivetrain to the whole world. ~Melea


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The final smaaby drivetrain.~Melea

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The TWA-1 in all its glory.~Melea

Specifications

Part Building Instructions:

With 11 custom manufactured parts used in TWA-1. The team needed to create design specifications for each part and instructions on how to make the parts. With these instructions, the team can manufacture the parts to the exact specifications anytime they need to. It takes the team over 7 hours to manufacture the parts for one TWA-1. -John Paul

Custom Steps For Parts:
1. 1010 - 1 7/8” in 80/20 – 120 minutes
  • Tap one end with ¼” tap
  • Mill for double anchor at the other end
2. 1010 - 16” in 80/20 – 20 minutes
  • Tap both ends with ¼” tap
3. 1010 – 11” in 80/20 – 30 minutes
  • Mill for double anchor at both ends
4. Universal Adapter – 90 minutes
  • Sand down sharp edges
  • Drill outer-screw holes to 3/16”
  • Drill inner holes to 5/32” in (standard Tetrix.)
  • Drill center hole ½” – Debur and check fit of shaft hub.
5. Side Plates – 60 minutes
  • Deburr
  • Drill ¼” holes out to 17/64”
  • Drill ½” holes out to ½”
  • Spin outside plates
  • Add serial number
  • Add sponsor sticker
6. D-Shaft ¼” – 120 minutes
  • Cut to 3.25 -0 to +1/8”?
  • Mill .055” deep and centered on flat + or - .002
  • Mill slot
    • Omni – ½” to 1” and 2 3/16” to 2 5/8”
    • Paint ½” Green
    • Traction – ½” to 1” and 2 3/8” to 2 7/8”
    • Paint ½” end Red
7. Tread – 30 minutes
  • Cut to 11 7/8”
  • Sew ends together with heavy nylon line. Each stich should be a independent knot.
8. 3D printed custom gear spacer – 30 minutes
  • Drill holes to 5/32”
9. Traction Wheel – 20 minutes
  • Assemble with Tread.
10. Hubs – 10 minutes
  • Replace set screws
11. Motors – 60 minutes
  • Mill slot - 1/8” to 5/8” from end
12. QA – 120 Minutes
13. Pack – 120 minutes

Total time – 800 minutes – 13 hours 20 minutes

Quality Assurance


Each custom part made will have a independent inspector inspect each part. The inspector can not have made the part. The inspector will be certified on the part they are inspecting. To become certified the team member will pass a certification test on each part and a review by a coach to become certified on the part. Mary

Current Qualifications of each team member:



Name
1010 - 1 7/8”
1010 - 16”
1010 – 11”
Universal Adapter
Side Plates
D-Shaft ¼”
Tread
3D printed spacer
Traction Wheel
Hubs
Motors
Owen
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Melea
Yes
Yes
Yes
Yes
Yes







Taylor





Yes
Yes

Yes

Yes
John Paul
Yes
Yes
Yes
Yes
Yes






Mary
Yes
Yes

Yes









Saatvik



Yes


Yes
Yes



Dakota
Yes
Yes
Yes
Yes
Yes
Yes

Yes




Jeremiah
Yes
Yes
Yes
Yes

Yes
Yes
Yes
Yes

Yes


Anthony
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes

Julianna
Yes
Yes
Yes






Yes
Yes


Below is the QA requirements for each part


1. 1010 - 1 7/8” in 80/20

a. Verify one end is tapped with ¼” tap

b. Verify a ¼”by 3/8” screw will thread into the end fully

c. Verify a double anchor is milled into the other end at a depth of .425” tolerance 0 to .020”

d. Verify a double anchor will install correctly and both screws start in the tie piece.



2. 1010 - 16” in 80/20

a. Verify both ends are tapped with ¼” tap

b. Verify a ¼”by 3/8” screw will thread into each end fully



3. 1010 – 11” in 80/20 – 20 minutes

a. Verify a double anchor is milled into both ends at a depth of .425” tolerance 0 to .020”

b. Verify a double anchor will install correctly and both screws start in the tie piece.



4. Universal Adapter

a. Verify all edges are deburred

b. Verify a #8 screw will fit in the outer-screw holes.

c. Verify a #6 screw will fit in the inner screw holes

d. Verify a shaft hub will fit in the center hole.



5. Side Plates

a. Verify all edges are deburred

b. Verify a 1/4” screw will fit in 5 top screw holes.

c. Verify a bearing will fit in the 3 bearing holes.

d. Verify the plates are spun on both sides of each plate

e. Verify the correct model and serial number is on the plate

f. Verify the sponsor sticker is on the outside of the plates



6. D-Shaft ¼”

a. Verify the shaft length is 3.250” with a tolerance of 0 to .125”

b. Verify the milling is 1/8 wide.

c. Verify the slot is .055” deep with a tolerance of -.005 to .005”

d. Verify the slot is centered on the flat with a tolerance of -.002 to .002”

e. Verify the slot lengths

i. Omni – From the green end ½” to 1” and 2 3/16” to 2 5/8” – These are minimum and they can be longer by up to .25”

ii. Traction –From the red end ½” to 1” and 2 3/8” to 2 7/8” – These are minimum and they can be longer by up to .25”



7. Tread

a. Verify The tread fits snuggly around the wheel

b. Verify each stich independent knotted.

c. Verify 1/8” Tarred heavy nylon line is used.



8. 3D printed custom gear spacer

a. Verify a #6 screw will fit in the screw holes

b. Verify all edges are deburred.

c. Verify the spacer is .205" thick with a tolerance of -.010 to .010”


9. Traction Wheel

a. Verify the 6 inter post are installed.

b. Verify the three screws holding the wheel are tight and the screw heads are in round holes and the nuts are in hex holes.

c. Verify the tread is installed and will not slip on the rim.



10. Hubs

a. Verify in the ¼” and 5mm hubs that the set screw have been replaced with a 10-32 - 3/8" half dog set screws. The set screws should be just started.



11. Motors

a. Verify the milling is 1/8 wide.

b. Verify the slot is .055” deep with a tolerance of -.005 to .005”

c. Verify the slot is centered on the flat with a tolerance of -.002 to .002”

d. Verify the slot lengths from end of shaft 1/8” to 5/8”– These are minimum and they can be longer by up to .25”








Bill of Materials - BOM

Parts List and Cost

The Bill of Materials list all the parts that are used in TWA-1. The parts are sorted by the supplier. We use 7 world class suppliers for the parts to TWA-1. The BOM identifies how many parts are needed for each subsystem and the total number of parts and the cost each and then the total cost. Some parts are donated to help lower the cost of TWA-1. Leonard Metals is donations of laser cut parts. Our goal is to not earn money, but to help teams unleash their full potential. -Owen

Supplier
Part Description
Cost each
Omni Wheel
Drive Wheel
Frame
Motor Gear
Total
Cost

80/20
10-10 - 80/20 - 1 7/8" long
17c per inch


10

10
$0.00

80/20
10-10 - 80/20 - 10 7/8" long



2

2
$0.00

80/20
10-10 - 80/20 - 16" long



2

2
$0.00

80/20
Double anchor



14

14
$0.00

80/20
Weld nut spring



20

10
$0.00

AndyMark
AndyMark 40 - 150 RPM Motor




4
4
$120.00

LM
Drive plate 1 - Aluminum .125" thick



2

2
$0.00

LM
Drive plate 2 - Aluminum .125" thick



2

2
$0.00

LM
Universal adapter

8
4


12
$0.00

McMasters
#6 Lock Washer
0.01
32
16

16
64
$0.64

McMasters
#6 x 3/4" screw
0.09
16
8


24
$2.16

McMasters
#6 x 3/8" screw
0.09
16
8


24
$2.16

McMasters
#8 lock washer
0.01
48
24

16
88
$0.88

McMasters
#8/32 x 1/2 screw
0.13
48
24


72
$9.36

McMasters
1/4in washer
0.04


24

24
$0.96

McMasters
1/4 x 3/8 flanged screw
0.32


10

10
$3.20

McMasters
1/4in x 3/8 in nylon spacer
0.09


12

12
$1.08

McMasters
3&1/4in long 1/4 in shaft
$7 per foot
4
2


6
$12.50

McMasters
10-32 - 3/8" half dog set screw
0.15
8
4

4
16
$2.40

McMasters
M4 × 12 mm
0.09



16
16
$1.44

McMasters
M3 × 6 mm
.09 each



16
16
$1.44

McMasters
1/4" x 3/8 Socket head screw
0.2


20

20
$4.00

McMasters
1/4" well nut
0.21


20

20
$4.20

McMasters
3/32" Allen Wrench
0.82


1

1
$0.82

McMasters
9/64" Allen Wrench
0.93


1

1
$0.93

McMasters
7/64" Allen Wrench
0.85


1

1
$0.85

McMasters
3/16" Allen Wrench
1.54


1

1
$1.54

McMasters
5/32" Allen Wrench
1.31


1

1
$1.31

McMasters
2mm Allen Wrench
0.79


1

1
$0.79

McMasters
3mm Allen Wrench
0.89


1

1
$0.89

Servo City
1/4 x 1/2 in. Bearing
1


12

12
$12.00

Servo City
1/4in shaft hub
3.75
8
4


12
$45.00

Servo City
100 tooth gear 32 pitch
10.2



4
4
$40.80
Still need final price
Servo City
6mm D shaft hub
5.4



4
4
$21.60
Still need final price
Servo City
Shipping






$7.00

Servo City
84 tooth gear 32 pitch
9.75
4
2


6
$58.50

TA
3D printed custom gear spacer

4
2


6
$0.00

Vex
Omni wheel
17.99
4



4
$71.96

Vex
treed 1 1/2" by 11 7/8"


2


2
$5.00

Vex
Shipping






$10.86

Vex
Vex 4in wheel


2


2
$27.98









$474.25


Marketing

Sales brochure

We put together this flyer to send to other teams. It contains details about the drivetrain, including what parts it contains, why it is a great option for a drivetrain, and pricing for it. -Saatvik


Video


Assembly Guides

Step by Step guide

The step by step guide contains instructions so simple, anybody can do it. All parts are labeled, and there are detailed pictures describing the steps necessary to construct the drivetrain. ~Mary





Video


Sales

Product Pricing


We are selling this drivetrain at cost to help other FTC teams become more competitive. Techno Warriors Advanced donates over 7 hours preparing parts for each kit.
· Priced at $500 plus shipping.
· Optional drivetrain width from 15 to 17 7/8 inches. Standard width is 17 inches. No additional cost.
· Hex cut hole pattern on the outside side plates can be changed to your team number for a $20 fee.
· If you have AndyMark motors we can ship the kit without motors. Subtract $120 *
  • The motors we supply have machined motor shafts for half-dog setscrews. Without this machining, the set screws will tend to loosen over time and fail even if Loctite is used.

-John Paul

Testing

Testing the Robot's drivetrain is very important if others want to see for themselves how efficient it is. The following tests show the data we collected from testing the spin time, the side drag test, the pull weight, and the straight line test. All tests include different weights to see how well or how badly the drivetrain performs. We then recorded the results. ~Mary




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At zero pounds on the Robot, the spin time was at 1.1 seconds. This stayed consistent with 10 and 20 pounds, until thirty pounds was added. After that, the spin time increased steadily. ~Mary

The Spin Test tested how fast the robot could spin 360 degrees.
  • The drive field used standard FTC field tiles.
  • Total robot amps were recorded for each run.
  • Time to spin 360 degrees was recorded for each run.
  • At least 4 tests were recorded for consistent results.
  • The robot was weighed for the base weight.
  • 10, 20, and 30 pounds were added to the robot for each run.

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This is arguably the most important test; on the playing field, agility is key to competing in the game effectively. As you can see the TWA-1 performs superiorly in this test. ~Melea

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At ten pounds, It took 16.5 pounds to move the robot. As more weight was added, the amount needed to move the robot sideways remained around 6.5 pounds over the original added weight. This remained until around 40 pounds, where it took only five pounds over the proposed weight to move the robot sideways. ~Mary

The Side Drag Test tested how much weight it took to pull the robot sideways.
  • The drive field used standard FTC field tiles.
  • Time amount of weight to pull the robot was recorded for each test.
  • Weight was added until the robot was pulled sideways.
  • The robot was weighted for the base weight.
  • 10, 20, and 30 pounds were added to the robot for each test.


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The TWA-1 performed spectacularly without fail in this test. The 10 wheel drive was nearly un-pushable. Please note the weight added to the system because some robots do not perform well with a robot this heavy.~Melea
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At 10 pounds, the robot could pull about 2.5 pounds over its weight. this remained true for 20 pounds. However, it slowly started to decrease it's pulling capacity at 30 pounds. ~Mary

The Pull Test tested how much weight the robot could pull
  • The drive field used standard FTC field tiles.
  • Total robot amps were recorded for each run.
  • Time amount of weight lifted was recorded for each test.
  • Lift was added until the wheels slipped or the motors stalled.
  • The robot was weighted for the base weight.
  • 10, 20, and 30 pounds were added to the robot for each test.

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The holonomic drive and the four-wheel plus Omni are not competitive as defensive robots and will be easily pushed around by other robots. The tread robot's data is high but proportional when compared to other designs because of the wheel size difference. The TWA-1 performs well and consistently in this test, proving its potential as a defensive robot. ~Melea

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The straight line test showed that with ten pounds on the robot, it was capable of driving 16 feet in 4.5 seconds. With 20 pounds, it took 4.6 seconds, and 30 pounds 4.8 seconds. However, as the graph shows, at 40 pounds, it took 5 seconds to ride 16 feet. ~Mary

The Straight Line Speed Test tested the robot on how fast it would travel 16 feet.
  • The drive area had a starting area to allow the robot to reach full speed prior to the course.
  • The drive field used standard FTC field tiles.
  • Total robot amps were recorded for each run.
  • Time to drive the 16 feet was recorded for each run.
  • At least 4 tests were recorded for consistent results.
  • The robot was weighted for the base weight.
  • 10, 20, and 30 pounds were added to the robot for each run.

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As you can see in the above graphs, TWA-1 performs very well. TWA-1 consistently functioned well with weight up to 40 pounds. ~Melea


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  • Just for fun, a team member rode the robot. The speed was recorded, and it took 6 seconds to cross 16 feet. ~Mary