Thursday, January 16, 2020

2020 Day 13: Prototypes are working

Shooter

The shooter prototype was updated with a more rigid hood and basic velocity control on the NEO motors. It's shooting with 2 NEOs powering a 6" wheel 1:1 at 5000 RPM and a 4in accelerator wheel powered by 1 NEO 1:1 at 5000RPM. We plan to update the shooter to gear the main flywheel up so the NEOs have more power head room to maintain an RPM of around 5000. We also may test powering the accelerator wheel off the same two NEOs that are powering the main fly wheel.

FullSizeRender

Intake

Our newest intake prototype is meeting all our expectations for an intake. The balls are rapidly moved up into our robot and our new indexer should be able to sort out the 3 wide balls pretty easily in the unlikely case we are intake 3 balls all sitting next to each other.
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VID_20200116_174326864
Video

Indexer

The indexer prototype based on FRC#6135 is working flawlessly. 
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Video of it working without intake
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Video

More Pictures and Video of all the systems are available in our photo gallery. 

Spectrum Dead Axle Rollers

The roller setup we have been using in our prototypes are based on a system we developed for our 2019 Cargo intake. We plan to use it again for our Power Cell intake.

The system has 6 parts
  1. 7/8" Aluminum Tubing 
  2. 1.125" ID x 1.25" OD Polycarbonate Tubing
  3. McMaster Tube Connecting Nuts for 7/8" Tube
  4. 7/8" ID x 1.125" OD Needle Bearings
  5. 7/8" Push on Retaining Rings
  6. 3D printed Clamp-On Pulleys

  • The 7/8" tube has the tube connecting nuts (star nuts) pressed into the ends of the length you need to span and is bolted into place on the ends acting as a standoff between two plates. 
  • The needle bearings go in the ends of the polycarbonate tube after you cut it to length. 
  • The push on retaining rings hold the tube and needle bearings in place. 
  • The 3D printed pulley clamps over the polycarbonate tube so it can be driven by a belt. 
  • Any rubber tube of your choice can be applied to the outside of the polycarbonate tube to provide grip on the game pieces. 

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Spectrum

2020 Day 12: New intake/indexer Plan

Block Robot Update

The new intake plan, allows for balls to rapidly be brought into the robot with a wide intake, and set quickly into the tower using a powered V similar to prototype videos from FRC#6135FRC#4481 and FRC#95 . We plan to prototype some variations of this idea by adding a central channel for balls to rolls straight down and possibly a powered belt to move balls towards the tower belting as well. We will test various options for the side conveyors/wheels and also speeds and direction changes.
The tray on top of the intake is designed so this robot would be able to load from the human player station with the intake down. That should allow us to intake balls on the ground and then quickly get any remaining needed balls from the loading bay when drive in.
Block Robot 1-16.PNG

When retracted the intake acts as a cage around any balls remaining in the funnel to not allow them to bounce out of the robot as we drive over the boundaries.
Block Robot 1-16 #2.PNG

We have prototypes of these systems under constructed and will post video and photos when they are operational.

Spectrum

Wednesday, January 15, 2020

2020 Day 11: Design Review Week 2

Tuesday = design review day

Here are some of the slides from today's review put together by each of the subsystem lead groups.

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Intake Week 2.PNG
Intake week 2 #2.PNG
Climber Week 2.PNG
Buddy Climb Week 2.PNG
Shooter Week 2.PNG
Shooter Week 2 #2.PNG
Photo of V2 Prototype using HYPEblocks, hopefully we will have some testing tomorrow. We have to refactor the hood a bit.
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Controls Week 2.PNG


Spectrum

Tuesday, January 14, 2020

2020 Day 9 & 10

Everybot and Week 6 Robots

This past Sunday, Spectrum was able to attend an event hosted by the Robonauts were Everybot and Week 6 demonstrated game play together. Both robots were very well done for only needing one week to complete.

Takeaways (Some are just confirmations of what we already knew)
  • The outer goal is very large. Week 6 was able to easily manually aim their robot to score consistent shots.
  • Fast low bots may have value in getting up to the RP level of balls but you need to be very quick in getting balls dumped into the goal and quick at intaking balls. Everybot does both very well.
  • The balance even on the wooden switch didn't seem hard to accomplish. A reliable and consistent climb will be incredibly important.
  • Driving across the Dance Floor (rendezvous points) will test how robustly made a lot of robots are. Make sure you test your robot driving over 1" bumps (the kit 2x1 is a good approximation) before coming to your first event. We are going to see a lot of radios, roboRIOs, batteries and other electronics and connectors come loose if they are only zip tied loosely to robots.
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More photos and videos are in our photo gallery.

Shooter Prototype V2

Hopefully will have test shots tomorrow after we make it a little more rigid.
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Intake/Indexing

Intake and indexing plans are still up in the air. We are re-investigating an intake similar to 971's from 2012. At first we didn't think it would package nicely but after some other changes to the design we think we can make it fit, but we need to build a better model to make sure it will index the balls fast enough for our robot.

Indexer.PNG


Robots that inspired us today

2012 - 971 (intake & ball funneling), 2056 (ball funneling)
2013 - 180 (shooting game objects inside of your robot)
2017 - 125 ( 4-bar intake)

Spectrum

Sunday, January 12, 2020

2020 Day 8: Quick Update

Power Cell Shooter Testing

Quick shooter testing video from today, we are now starting to believe we can make a more consistent shooter. Our plan is to have a wide 6" wheel and concentric flat hood. That will be were are next shooter starts.

https://photos.spectrum3847.org/2020-FRC/2020-Build-Season/i-ptLfBsS/A

Block CAD of the Robot

As subsystems start figuring out how much room they need we star laying things out in quick block sketches to make sure we won't have systems needing the same space and see how we can leverage nearby subsystem together.

This is all very rough and almost none of this other than the drive train will actually be on our robot. It's also missing an intake at the moment as we are still figuring out exactly what that will look like.
Spectrum

Saturday, January 11, 2020

Day 7: Making a few shots and a lot of misses.

Shooter Testing

We modified the shooter from our 2017 robot to be able to launch power cells. It's mounted to our protocube (just a cube made of 2x4s but we find lots of uses for it).

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In 2017 it was one 775pro geared 4:1, it's now 2x 775pros geared 2:1. The hood has 1/8" rubber sheet to ensure the ball is rolling and doesn't slip on the polycarbonate panel. This shooter was based on the FRC#33 2017 shooter when be built it that season.

It shoots with 4 solid Fairlane nitrile rollers (RR-754-35W-RP). It also has been setup with two smaller diameter accelerator motors to attempt to have the effects of hand feeding the ball some what mitigated.

We are running it currently without velocity control, we have a small tachometer and it shows that the wheels are spinning at 5700 RPM at full voltage. This shows that the 775pros motors are having trouble getting the wheels anywhere near their free speed.

Video of some of the initial test can be seen on our photo gallery

This shot was about 25ft.
The compression at the tightest was around 2.5" (4.5" from wheel to hood).

Part of goal is to see how we can make consistent shots with a variety of balls. We will continue to play with this shooter setup tomorrow to see how we can improve consistency.

Our next prototype will be moving up to a 6" wheel to get it closer to the correct RPM range for the free speed of NEOs at 1:1 or slightly over driven.

3D Printing Prototype Parts

All this week we have been printing parts for prototypes.

Today we started making some larger parts. Wheel extension on the left, intake ramps on the left.
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We have use countless Protopipe parts as well we printed up a bunch of HYPEblocks for the next iteration of our shooter prototype.

Robots that inspired us today

2017 - 33 (shooter)
2019 - 148 (elevator chain attachment)
WCP - Greyt Elevator V2

Sketch of the Day

Figuring out some of our climber geometry
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Spectrum

Thursday, January 9, 2020

2020 Day 6: Advancing the complete idea

Robot Design Plan Updates

A little more thought, some more white board drawings and conversations, and a few bench tests have led us to a few design changes for our prototypes.

1. Shooter - reduce some complexity with fewer rollers and feed wheels than planed. Shooter and tower moved towards the front of the robot, to allow a much easier ball path while keep the intake behind it.

2. Shooter Hood - Two positions, a long wide shot that will make a ball into the 2 pt goal from behind mid court and up to the initiation line and a shallower angle that is specialized for 3 pt goal from a smaller range on the field. We are currently choosing to not shoot from the target zone.

3. Shooter Tower - Stop balls from entering the shooter by decompressing the top of the tower by moving one of the belts away from the ball. 

4. Climber - doesn't need to be directly over our CG it's okay if we curl a little while we solo climb as long as our climber is rigid. Climber has also moved to a standard single stage 2x1 elevator as it now longer needs to stay below our shooter path as the shooter is turned around on our robot.

5. Buddy Climb - The buddy climb forks are now powered down instead of being sprung down. We believe this will let us make it easier to keep the forks on the floor even if our CG isn't directly under the hooks.

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Drive Train Update

CAD has been underway on our drive train since Sunday. There is still work to do but it's coming along nice. We have had issues with a large sheet metal front rail on multiple instances so this year we are planning to combine sheet metal drive rails with an extrusion cross bar that are put into compression with threaded rod and some 3D printed inserts on the side of the tube ends..


Robots that inspired us today

2013 - 610 (drive construction)
2019 - 148 (elevator & climbing legs), 971 (climbing legs and bumper mounting)

Sketch of the Day


Spectrum