March 9, 2020

March 9:
Shooter:

  • We found out that the belts didn't fit so new pulleys were printed

  • Belt for one side was assembled, other side will be done tomorrow

Tigger:

  • Compressor and 2 spark maxes were taken out to make room for Tigger

Indexer:

  • We found out that the indexer didn't fit (the motors are in the chain)

  • The chains on the drive train were swapped to make room for the indexer

  • The indexer should fit now (although very tight), some modifications of the poly carbonate panel may be needed

Intake:

  • The elevator end of the pistons were moved down 1/2" so that the intake is both inside frame perimeter when retracted and can be lowered

  • Only very basic testing was done

  • A bolt was moved to the left piece of 1x2 mount for the intake so there are now two bolts in opposite corners, making the structure more stable

  • The two big washers for the bottom churro of the intake were swapped for smaller washers

March 6, 2020

Shooter:

  • We put on the Coulson's and 16T pulleys and 55T belts on

  • We attached the NEOS

V-Indexer:

  • We tried to attach the v-indexer to the robot, however it was pushing on the chain so we are in the process of taking it apart and changing some dimensions

Tigger:

  • We attached the polycarb plates to tigger but still need to move around some wires and fix golden churro so it will fit the on robot

February 21, 2020

Drive train: We finished tensioning chain properly, it should drive now.


Intake: Cut the hex shaft, ran it but it sounds like the gearbox is fully ungreased. We'll disassemble and regrease when we take it apart to add bolts and fix belts, once the next set of hex shaft arrives.

Indexer: We drilled holes in tigger for the support pieces and cut those. We also assembled the 3:1 gearbox, and decided to cut the motor output shaft instead of making a groove for it in the support tubes. We'll rivet it together on Sunday.

Climber: We decided to use a 1x1 or 1x2 hook, and revert back to the original gusset design, since we can slide it around to avoid interference. We should be good to start assembly on Monday.

February 19, 2020

Drive Train: Today we fixed the gearbox problems we were having, and the drive train gearboxes seem to be working a lot better! The problem that we fixed was with the right gearbox. We had a bolt that was loctited using red loctite, but it was only bolted in halfway. We had to break the red loctite and unscrew the bolt and rebolt everything together. We also replaced the aluminum pinions on the drive train gearboxes with steel pinions, so we could use the aluminum pinions on our mechanisms.

Intake: We mounted the versaplanetary on our intake and realized that the tension from the pulleys was bad for the bot. We are currently working on fixing this issue.

Tigger: We started making the gearbox and attacthing it to a piece of 1x2 for Tigger. We were having a few spacer and bearing issues and are we are currently trying to resolve this issue.

Indexer: We adjusted the shaft lengths and put pulleys at the right height, and started working on the gearbox.

February 18, 2020

Drive Train: We fixed the problems with our gearboxes and tried to diagnose where the clicking sound was coming from. We completely stripped the right side of the robot so only chains and sprockets were on, however the clicking sound was still there. So we stripped it even further until the drive train was only versa blocks, hex shafts and bearings. We turned those and there was no sound, so we realized the problem was most likely in the chain. We then fixed the pushed out bearing problem in the second gearbox.

Right before we left we did a test drive with the driver tryouts layout. The gearboxes seem to be fixed, although we did notice two problems: one of the bolts holding the wheel in fell out and could not be found, and on the other side the colson slid on the hub towards the versa block. The former can be easily fixed by allowing the loctite to cure, while for the latter, we'll probably glue the wheel to the hub, although we have not yet figured out what kind of glue to use.

Intake: We started to figure out where the placements of the vertical hex shafts should be on our indexer.

February 15, 2020

We worked in John Polyani's shop.

Drive train: We were doing driver practice and tryouts when we noticed that our screws holding the versa blocks onto the drive train were coming out and rubbing with the wheel, causing the wheel to become damaged. To ensure this wouldn't happen again we used loctite on all the bolts including the ones attaching the gearbox to the versa blocks. These ones were a little trickier to loctite and put back in because the gear box was blocking our point of entry. So we had to disassemble and reassemble part of both of our drive train boxes. We did some driving on the field and our robot can vroom vroom really nicely. It seems to be able to go over the 1 inch raised boundaries in the Rendezvous Point very nicely.

Intake: We put in the 1x2 bar with the lead screw and plugs and attached it to our intake with thin nuts. We discovered that the churros were cut too short, so we need to get more churros cut.

Indexer: We drill pressed holes to attach the indexer to 1x2 and the robot

Tigger: We started drill pressing 1x2s to create Tigger, and decided how to use triangles to make Tigger as structurally integral as possible.

February 7, 2020

We tested Tigger with the hood idea, but along the way, we discovered that Tigger wasn't working anymore. The last ball in the indexer wouldn't come out because it wasn't in contact with the compliance wheel. To try and fix this we are going to test Tigger with an extra hex shaft we added between the top hex shaft (with the compliance wheel) and the second hex shaft. Result TBD. We also discovered that our drive train was having a few issues, but they were all fixed. We also drove the drive train (yayy) and tested some drive train code. There were some mechanical issues with the assemble of the gear box but they were fixed.

February 5, 2020

Our robot actually drove for the first time! We also start making the indexer and cut some of the various little pieces of tubing for our mechanisms. Intake design is finalized and the indexer bottom is mostly as well - we are exploring using tubing instead of flat pieces to support the polycarb now. Other elements are continuing to move along, but slowly.
Tigger (indexer) testing suggests a hood above the top of the roller will help move balls out well, though not accidentally outtaking is now an issue. The belts and crowned pulleys are working really well, we'll stick with them for final.

January 30, 2020

After the de-stress team-building meeting, we continued to build the gearboxes. One side is done (save for the wheels), and the other is nearly there. Tech leads decided to build a non-fourbar ("spectrum style") intake, since it's simpler, smaller, and currently the geometry is a lot better. Most subsystem CAD might be done by the end of this weekend, it's making a lot of progress.


Fun news! Our robot "drove" for the first time today! 

January 28, 2020

We continued to test the shooter today to find an optimal angle and speed for various distances. The shooter has a kP of 0.0015 and a kF of 0.000225. RPM is measured on the motor, not the shooter wheel. The shooter is mounted on a table 30in off the ground. At 350in, 2850 RPM and 13 degrees can get the ball in. At 420in, 3350 RPM and 20 degrees can get the power cells in reliably. Currently 20 degrees seems like the optimal shooter angle, being able to shoot consistently from 10-35ft from the target. This angle was not tested at 350in but worked for shorter distances. The max RPM required was about 3600 for shooting at 10ft @ 20 degrees. The shooter takes about 1-1.5 seconds to recover to full speed after shooting a single power cell. At high velocities, shooting multiple power cells in a short period of time may cause the battery to brown out.

January 25, 2020

(CAD meeting)

DT CAD updated to have most of the shaft spacing identified, and new wider wheels added. Indexer tower is almost buildable, including motor mounts, but mounting details of the whole system aren't quite finalized. It's highly dependent on shooter geometry, so we'll be waiting on that for a while.
There are now three ideas for intake:

  • two bars with a pivot (2 motors). This one's easy to build and fit, but also easy to break due to the current pivot design. We're almost certainly not going this way, but it is the most developed right now.

  • four bar linkage, piston to drive in/out.

  • spectrum style, see the image. Essentially idea #1 but setup to fit under the shooter even when the rollers are stretched out. It might be impossible, we have no CAD of it
    Fundamentally they've all piston retracted 2 roller designs with pretty similar retracted volume, it's a matter of complexity, exact size, and packaging. We should be able to easily pick between them once the CAD of the latter two are more developed.

Elevator is started, we're looking at using the bearing blocks from the elevator prototype last year. It's a pretty simple design.

January 24, 2020

Indexer tower CAD started to look decent, we'll likely need to use a belly pan to support the tower since it's floating in the middle of the bot. The top feed objectives are essentially:

  • keep balls from coming out when we don't want them to (shoot exactly as many as we want)

  • have fast feed when we want to

  • allow the belts in the rest of the tower to keep spinning even when one ball is jammed at the top

  • simple

An essie-style large roller in tight compression powered separately from the belts should be enough, but the slipperiness needs to be controlled. A piston at the back of the tower might be useful to force balls through, and also prevent extras from going if it stays extended. That's probably unnecessary though.
Started putting some test wheels and stuff on the drivetrain shafts, one of the holes was misaligned with the versablock so that had to get filed. Not a costly mistake.

January 23, 2020

1x2 rails got assembled with new bolts, versablocks and cams were also added. Stopping the ball at the top of the tower jams the whole thing, but generally it's a very hardy mechanism that can take a lot of bad feeds. Belts derailing continues to be an issue, we'll replace the current spacers nubs with crowned pulleys which should really help things.

January 21, 2020

We worked on drivetrain and an indexer tower prototype. The gearboxes were under-toleranced and too small in a lot of dimensions, so we decided to re-CAD and re-CNC them. The drive frame rectangle was assembled today, though we're having the same issues with bolts we did last year. Turns out stainless-stainless nuts and bolts will essentially weld together, making them impossible to turn at some random point. Future members: don't buy stainless! We're looking at replacing all of those on the drive train. Chain was also measured today.
The new indexer tower just about works, and tomorrow we're going to start trying to jam it to figure out the ball stop mechanism.
In design, we discussed climber details. A Richard-style mechanism, even with a ring to keep rope mostly in place, would require very careful placement relative to cg, so it's likely too risky. Some rough simulations indicate we can build an elevator with 1x1 (as opposed to 1x2), saving some weight and size.

January 20, 2020

The electrical board was wired and arranged today - hasn’t been completed yet.

In terms of the shooter, we tested different angles and amps for optimum angle. We found that 2850 amps is the best number so far but it still doesn’t reach the inner goal. A continuation of the testing will happen at our next meeting.

January 19, 2020

The programming team has been working on the vision code for the past week. Today we managed to use OpenCV's solvePnP() function to estimate the location and orientation of the outer Power Port from previously taken test images of the field. The code is currently in Python for convenience and still needs to be implemented in C++ and ROS later. More testing is needed to determine the accuracy of the results. We've also borrowed a Limelight from 865 for a week to experiment with.

January 18, 2020

We've been building a new indexer for the last few days, it started working today. Moving balls up with belts is working really well, though we'll need to make sure they always stay in contact with a wheel at the back and don't fall out on the sides. There's some neat videos of it on our social media. We've identified the broad volumes of our robot in CAD, and it seems like a high-bay roller isn't going to work for geometric reasons. The shaft would interfere with the shooter supports. The elevator vs. Richard debate is still open - a single stage elevator would be tall enough to maybe get in the way of the shooter even when lowered. We're testing roughly whether this is a concern - a bar directly in front of the shooter can be up to about 2.75 in above the wheel center, and we're still looking at minimum required separation from shooter to a bar above the highest part of the shooter. More details on exact shooter geometry will change this, and we can likely make some design adjustments to make sure the elevator isn't an issue. Richard meanwhile would require a rope guide to reduce risk of G18 violation when climbing (red card). Richard also has geometry issues - with the current cable chain, it'd be quite large and would probably need to at least partially be behind the indexer tower.


Drivetrain CAD is nearly done, we figured out bracketing on the rails today. We assembling the lower set today. No other detailed CAD is ready, though we're planning to get indexer done this weekend, and maybe shooter or intake dependent on people's time.
Over the past few days, we've been doing a lot of disassembly of old robot parts, so not a ton of progress on the 2020 bot this week.