Day 24: Launcher Testing

Slow motion video

Captured with a Sony ZV1 at 960fps. You can see how much shaft wobble we are getting at speed. We do like that the note isn’t deforming much as we launch. This is now launching with 2x Kraken motors.

Video

New Banners?

We ordered some replacement blue banners (we managed to lose some) in December from the new banner company and they just arrived. The nylon banners are very different from the previous banners. They are only blue on one side and are very thin. The pole pocket is also much smaller. We don’t know if this is how official season banners will be or not, and we also don’t know what the Vinyl banner option looks like.

Day 23: Intake and New Launcher Testing

Intake Testing

Yesterday we were able to get some very basic driven intake testing done. We are very pleased with the results with just the basic printed diverters for centering.

Worn note

Video

Newer note

Video

Launcher Testing

We were able to build a new launcher prototype based on information we’ve gathered from a few other teams and the data in 95’s build blog here and here.

Here is the breakdown of the launcher

• 6 Shaft, 2in Wheel Launcher

• 2x Falcons with 36t pulleys and 18t on the rollers for 1:2 up gearing. Both motors are driving all 6 rollers. Most of the shots were done at 3.5k to 4.5k motor RPM (double for shaft RPM), Velocity is PID-controlled in these tests.

• Roller shafts  2.136” C-C, 40t belt distance for 18t to 18t pulleys

• Top and bottom rollers are spaced vertically 3.6” C-C to allow for 72t to 72t gear spacing.

• Printed pulleys everywhere which end up causing some problems and stopping testing for the night. (we rubbed the teeth fully off two pulleys)

• Wheels are mostly just what we had on hand.

• Black and grey wheels are 2 in AndyMark Stealth Wheels

• White wheels are 2in Fairlane Wheels 35A Nitrile with 3D printed hubs pressed in.

• Orange Wheels are 1.5” Banebots wheels, we don’t think they do anything but maybe stop the note from flopping around. Gap between them and the roller below is 2.1” so they shouldn’t be doing much.

• Each set of wheels is approximately 2” wide, so we are only contacting the note at it’s edges.

• The plywood plate for feeding is intentionally spaced away from the first set of rollers to allow the note to more naturally flow into the compression between the wheels.

Video shooting from about 16ft away and we were aiming for the corner and side wall of the speaker on purpose, again these are the first tests with a wobbly base, so lots of room to improve but much better than what we were doing before.

One of the melted thru pulleys

Day 22: Gripping the Ground

 This is our last update before we test durability. The only change is that we were able to test the VEX Grip V2 Tires. Here is the updated Data:

Here is our “Ground Hugger” Box. Onto testing durability.

Day 20 and 21 CAD updates

Alpha Robot

The alpha robot CAD has a more complete climber. We will be powering the slide climb (it will have hooks for the chain) from a MaxPlanetary at the rear of the robot that we will tension with a turnbuckle to slide it down the tube it is mounted on. The turnbuckle will be made from REV 10-32 Ball Joints and a hex shaft. The top sprockets of the slide chain and elevator chain will be coaxial with the elevator top sprockets spinning on bushing on the ⅜” hex shaft that will connect the two sides.

Competition Robot CAD

We have begun CAD for the competition robot. It will look very similar to the alpha in many ways. The process of re-CAD many of the mechanisms allows us the chance to redo our CAD with more knowledge. This means that things can be better organized as we have a better idea of what mechanisms and parts will be where, so our assemblies and part studios can be easier to work on. The spacing and dimensions can be cleaner for all the parts. Some of the systems will get major upgrades.

Here is the current SuperSketch of the robot.

The largest change from AM to the competition robots (PM/FM) will be the launcher pivot. We are planning to use a sector gear mounted into the launcher and a custom gearbox to pivot the launcher through around 70 degrees of motion. We are also planning to use a constant force spring to default the launcher to the up position and remove some of the backlash in the system.

We have also begun construction of the competition robots. Swerve plates have been powder-coated and a few of the modules have been assembled. We have also cut most of the frame rails.

Day 19: Amp, Trap, and Wheels

 Amp Test

We did more testing on the Amp and Trap mechanism. Here are some videos of our progress. Here are Photos and videos of these in action. There are more on our Photo Album.

balanced climb test

We made a low-fidelity version of our new climber to test the balancing. We feel confident with this design to keep moving forward with a higher-fidelity version for alpha.

Trap Test


Team 88 SLS Wheels

We recently tested SLS Printed Wheels from Team 88 on our traction jig, alongside our usual array of wheels. The goal was to see how these wheels were compared in terms of grip. We’d like to thank Team 88 and Formlabs for providing us these tires for us to test.

The data from our tests show that the SLS Printed Wheels provide superior traction. They outperformed other materials with the highest average angle and coefficient of friction (CoF) measurements. Here are our findings:

​​

	SLS Printed Wheels	Black Nitrle	3D Printed Spikes no Suspension	Treaded Neoprene	3d Printed Waves (White)	Slick Neoprene	Colsons
Test 1	68.5	56	47.8	56.5	48.5	45	42.5
Test 2	62.2	57	58	55	49	45	41.8
Test 3	65	57.2	60	57.3	47	42	42.8
Test 4	62.5	57.9	59	51	52	44.8	41.5
Test 5	64.8	57.1	55	55	52	45	41.2
avg Angle	64.6	57.04	55.96	54.96	49.7	44.36	41.96
CoF	2.106	1.542	1.480	1.426	1.179	0.978	0.899

While the SLS wheels lead in grip, we haven't yet assessed their durability. The next step is to test these wheels on our Alpha robot to monitor wear and tear.

Stay tuned as we continue to test and evaluate to determine the best wheel for our robotics applications.

Day 18: Design Recap & Testing Videos

More test videos are on our photo gallery (Slow intake tests had a 12A current limit set)