On Saturday, Comp and the drive team went into San Jose to practice driving on 254's full field while the hardware teams finished the R2B2 rebuild.

The practice session went well, and below are Mike's notes as they were posted in Slack:

• When the battery gets really low, the robot struggles to keep the arm up for L3 scoring. We might need to further adjust the gear ratio, but we can play around this for Port.
• We had one falcon power wire come out of the PDH. There is no strain relief so it just popped out. We need to fix this.
• We had multiple bad solder and strip joints in the CAN loop. The CAN issues are brutal and hurt big time in practice. We must get better and inspect all cables
• The e-chain mount on the arm broke. This needs an AL backplate
• One of the steering falcon shafts is coming loose. We should inspect and consider adding a output shaft support bearing like poofs do. Poofs also said they swap all their falcon nose bearings out.
• when switching swerve tread, one of the wheels was almost impossible to remove because of too much loctite.
• Bumpers are still too low.
• The rivets in the bellypan sheared. Let’s use high strengths.
• Intake power belts are still falling off/slipping and results in low/no power to the intake rollers. This is our most common issue.
• Grabbing from the shelf was working better than grabbing from the ramp. Both are challenging for our robot
• Cubes on the ground are proving tough for the intake to hold onto. We hope the newest intake is better in this regard.
• Intake skew is still a problem. We hope the new intake fixes this too.
• Software sequences are slow and could be sped up in places.
• The wrist chain was loose but never really skipped, which was good.
• Elevator DOF was solid
• Arm DOF was fine except for a few times the flathead holding the elevator drum backed out causing chain rub. There is potential gear tilt again that we should inspect.
• The 1/8” inner intake plate snapped. We need a spare cut.
• The swerve twitches at the start of auto, sometimes causing a cone miss. We need to look into ways to mitigate the twitching.

R2B2 was mechanically and electrically complete by about 5pm today, finally ready for drive testing.

Immediately after this, we found that the wrist doesn't have enough torque to lift the intake with a game piece in it.

 Beta is doing better than comp though, since Comp's wrist had fully snapped in half.

5 days until competition.

Something you sometimes hear mentors in FRC say is that robotics is a third space. Your first space is your home, your second space is your school or workplace, and your third space is where you have fun or pursue your hobbies. Your priorities in life should follow the same order. Your first priority in life should be your health and wellbeing, followed by your responsibilities as a student, employee, or parent, and finally in third is your hobbies.

With that in mind, this is the point in the season where work started to overtake FRC in my priorities list, and I stopped having time to be in the shop daily, and didn't have time to dedicate to this blog.

Following this, each post will be a summary of each event and how we spent time preparing for the next one. They are being written well after the conclusion of the season, using the pictures and information available to me in Slack. Hopefully next season we won't have an interruption like this in the build blog, but I hope you find the information here interesting and valuable nonetheless. Thanks for reading.

Regards,
​Matt

Oof

Oof

We're finally running full-field cycles in practice. Cone pickup from the shelf looks reliable, and Yi and Emma are working well together as a drive team. Unfortunately, the wrist belt is still killing us. At the end of the Thursday meeting we finally swapped it out for a #25 chain. Hopefully this should run more reliably.

(before)

(after)

Comp finally has a two-piece and balance auto. We're still pushing for a three-piece auto by Hueneme, but this is looking tough. We need to pull a lot of time out of the current program to make it work.

Beta's rebuild into Beta 2 (R2B2) is coming along. It will be the first robot to get the V4 Everybot intake, which should be more reliable with cubes. It also has the lower roller driven by a timing build instead of flat polycord, which will transfer torque better.

Finally, after seven long weeks of work and a lot of trial and tribulations, we finally have a single substation ramp. Go Citrus!

The long weekend at the end of build season is always a well-appreciated opportunity to push hard to get things done. Even with it, we're nervous for the upcoming event.

Ajay pulled out the old Pinball Wizard intake on Saturday (which is miraculously still together) and did some testing with the intake angled down at about 60 degrees. It worked, but it wasn't incredibly inspiring. We probably won't be playing with this much more before Port Hueneme.

The latest rev of the Everybot intake picks up cones well enough, and we could make it work for cubes with some good driving. We also fixed the "vertical acquisition zone" problem of the old one by adding a strut that rides on the ground to keep the height of the cone rollers consistent. What doesn't work is the wrist. The belt that runs the wrist skips a few teeth every time it's retracted, eventually running the inline tensioner back into the gearbox. Re-tensioning is a 20 minute operation, and it needs to be done all the time. This is unsustainable, and will probably kill us at Port Hueneme if we don't get it fixed.

One of the things we changed from Beta to comp was reducing the reduction on the arm. The original arm had enough torque to do serious damage to itself, so we removed a MaxPlanetary stage from it. It has plenty of torque to lift game pieces and do its curl... or so we thought.

Because the arm pivot is further into the robot than the wheels are, when it climbs the wheels get pushed into the ground. This pushes the robot, forks, and partner robot up a bit (and scoots our robot in towards the platform). The original arm had enough torque to push through all this, but the new one doesn't. We can make it work by climbing with a gap between the bumpers and the charge station, but this defeats the purpose of a last-second partner climb.

Compounding this, there was a week zero competition over the weekend, which showed that triple balancing with random unpracticed partners is... actually pretty easy. We might not even need the forks week one. It's possible that we leave the arm as-is and ignore the fork climb at Port Hueneme. As with everything, this is TBD.

With all this bad news, the mood is a little grim around the shop. The good news is that we weighed in at 79 pounds, which is completely bonkers.

I was out sick for a week, so this will be a summary update for Week 6

Mike has been on a tear coming up with new intake concepts lately. The direction has changed a few times, but the new settled course is that we are setting the 111 French Fry intake aside, and bringing back the Pinball Wizard from a few weeks ago. Because we have a wrist now, we think can attack game pieces at a downwards angle, reacting against the floor to help keep the game piece stable enough to intake.

We will be testing the Pinball Wizard again this weekend to see if it can fill our needs. One downside of this design is that the rollers spin perpendicular to the wrist, so we can't power it from the base of the carriage like the Everybot intake (below).

Comp is almost completely assembled. This is still missing the climb forks (about a pound) and a 7 pound steel bellypan that we had cut at Fabworks by our friends at 4414. The Rev 3 Everybot intake is also 2 pounds lighter than the Rev 2. With all that, we should still be weighing in at just around 90 pounds. We should still be fast, light, and low!

Now that Beta is working well enough to score points, we're finally making some autos. First up is a single game piece and balance. We're able to do this consistently.

With Beta's intake working unreliably and Software Robot programming autos (and with Yi being both the head of Software Robot and the driver 🙃), there has been very drive practice done this week. The log sheet for our short cycles at least includes cones now.

Today was our first earnest day of drive practice, and week 6 starts tomorrow. Yikes.

Prior to the meeting, Taye reversed the problematic pulleys in the intake. It now runs slow enough to pick up game pieces reliably, but too slow to pick up game pieces with the robot at full speed. The Markforged print was made with a 1/2" hex bore, but it turns out the shaft is 3/8" round. We quickly printed and installed a PLA pulley instead.

The goal of today's practice session was to get good at positioning and scoring. The original plan was to run batches of 6 cones, 6 cubes, and then get in position for a climb. We decided against playing with cones today, and were running cube-only cycles. This is the log sheet for the day.

We ran our first few cycles with Beta today, which immediately exposed some flaws.

The biggest problem is the intake. In an effort to only use the belts we have on-hand, we ended up running a belt stage as 24:18 instead of 24:24 as planned. This "upduction" is causing the intake to hit its 40 amp limit while idling. It also takes about 5 seconds to get up to speed under a current limit, and browns out the robot. We drained our first battery in just four cycles. We're printing a new pulley tonight to swap the reduction from 24:18 to 18:24. That should allow us to cycle normally, but probably not to grab game pieces at full speed - we can live with that until Comp is ready.

The second problem is our weight distribution, as previously mentioned. With a heavy intake and solid aluminum climb forks, the inertia of snapping the arm down while moving causes the robot to wheelie dramatically as it backs out from scoring position. Comp will have a lower CG and a lighter intake, but that might not be enough to solve the problem. Getting the Software Robot team to slow down the arm lowering should help as well. It could move downwards at 20% its current speed without slowing our cycling.

We also backed out the screws that hold the plate onto the middle stage of the elevator, which will need loctite.

"Steal from the best, invent the rest," right?

Wildstang (111) has been doing an open build this year (one of the best of the season, and my personal favorite robot so far - check it out if you aren't already familiar). They posted their intake on CD on Saturday, and this thing is too good not to build one ourselves. Ours will have a few twists, of course. The 111 intake has to work both directions, which means it has to be symmetric. Ours doesn't.

One of the easiest changes we can make to the 111 "french fry" to intake mitigate that issue is to extend the upper half of the belts. We will also be changing the intake to be full-width with polycarbonate dead axle rollers instead of hex shafts, and figure-eight belts instead of gears to keep the weight down. Our wrist will pivot from above the centerline of the intake to keep cones from stabbing into the pivot point, and to help it package easier. Comp will get the modified Everybot intake for now, and when Beta evolves into R2B2 it will get the French Fry (Wildfry? French...stang?) intake to compare against.

Rohan, Aunish, Hiroshi, and Raf got Beta wired up and into the Software Robot teams' hands. Yi got all of the individual degrees of freedom working, along with a first pass at set points for the elevator, arm, and intake. On Sunday, Beta made its first complete climb. There are still some minor mechanical parts to install, but this is nearly complete. We're also not excited about the string wrap onto the drum (it overlaps itself sometimes), so we might make Comp's drum larger diameter.

We spent some time playing with the intake. Note that the perspective on this video is a little confusing. The intake is in its "tucked" position with the elevator up, so it's upside down from its usual orientation. The climb forks have pool noodles on them to keep anyone from injuring themselves on them.

By the end of Sunday we were able to score our first game pieces. This means that we can start programming autos and running drive practice in earnest. By this point last year we had dozens of hours of drive practice, and this year we have none. We have the same driver this year as last year, but our operator Emma will be behind the glass for the first time at Hueneme, and this is a hard robot to operate.

The Hardware Design and Fabrication teams got Comp's drivebase built, and Hardware Electrical started getting it wired up. We hope to have it built next weekend.

How does this happen every year? Kickoff happens, then you spend a few hours looking at plywood prototypes and then suddenly it's February and you're behind schedule. We should be running cycles right now, but instead we're still building Beta. I've gotten behind on updates, so today's will be short while I catch up.

This week we got Beta mostly assembled, and ready to wire up and string the elevator. The limelight mounts still need to be designed and printed along with a few other small details, but the robot is mechanically functional.