Reefscape (2024 - 2025)

Lead: Sukhesh | Students: , Alex, Otto, Jason, Sacheth, Ryan, Thomas, Angel, Thadd | Mentors: Mentors: Mr.McEntire, Mr.Davis

As this was my last year, I wanted to make the best robot the team's every made in its entire history. At this point I thought my CAD abilities were beyond what was needed for FRC, so my self-imposed goals were related to things outside of CAD:

• Clear communication with all subgroups on all design changes and decisions
• Passing knowledge to the future students
• Set an example of what this team is capable of achieving (basically break through our manufacturing and assembly capabilities)
• Experiment with future opportunities for CAD

The mentors and I already knew that this season was going to be difficult for CAD as I was the only one who had experience doing CAD at a robot making level. It was already assumed before the season started that I would have my hands filled with CAD work, with limited opportunities to let students work on the robot. Nevertheless, I still tried my hardest to switch gears from a student to a teacher.

Off-season

I'm often complimented for being very passive and I guess "chill". I'll admit this skill is super useful in a high pressure role like CAD lead, who has to deal with so much stress like continuous iterating, meeting deadlines, and handling criticism on design. The problem I faced was letting this personality seep into teaching. I was being too lenient with the new students who were... distracted (to say it nicely) and honestly I wasted a loooot of time. I figured the best I could do is record lessons and post them on my Youtube channel because it wasn't fair to the students who were already ahead having their time wasted.

A series on CAD I started which I think has some pretty useful things in it (at least in the other videos)

Similar to last year, we also did a robot in 2 months challenge:

I could not get the new students involved because they simply didn't know enough at the time, and I felt that I would be rushing them If I let them take charge of the robot. The calendar for the robot expected CAD to be done in a week and a half, realistically not enough time for the new students to even dive into the robot. I took the rational approach of letting the new students on the other subgroups have the time to learn on this robot then focusing on just my subgroup and compromising all the other subgroups.

Honestly I didn't put much effort into this robot because I was quite busy at the time on other things so we had to cut some corners on the ball shooting and just focus on putting the hatch panel inside the shoot. This was also the first time I ever made an elevator and I didn't have much of a clue what I was doing and just stole designs off other robots. (It was pretty challenging to understand how continuous and cascading worked in terms of rigging). I also learned the importance of having as much overlap as possible in the elevator to keep all the stages as sturdy as possible, as seen in the picture above, to prevent too much stress in the bearing joints.

In december I came to the realization that it wasn't the students that were the problem, it was me. Being a teacher is difficult, and I realized at that point that I had to learn to find and adapt to each student's preference of teaching. A bit too late of a realization, but It was a nice learning lesson for later in life if I'm ever in a teaching position again. On a side note, I spent time learning more about Altair and doing preparation for the build season through new Onshape custom features.

The first successful motion analysis which produced the most physically optimized piece for the spyder arms. Along with the pitchforks it created, it also showed me the exact torque it required to do the motion I wanted the arms to go through and using that calculation I could find the ideal gear ratio to rotate the arms. It also gave so much more information like forces at any point and displacement, but that was a bit too much for just a frc robot.

Build-season

The most mechanically advanced, coolest looking, and functional robot in the team's history: Agent Stingray

Agent Stingray (2024 - 2025) (opens in a new tab)

Brainstorming

This year, I was given a LOT of creative freedom compared to all the other years. I realize it's mainly because I was a senior and that most of the team were new students which meant less opposition to my ideas (I think it's a good and bad thing lol). This was this year's robot goals:

Stingray Mark I

First iteration of the robot, featuring a cable driven 3 stage cascading elevator with an intake that can manipulate both coral and algae and a W shaped climber

Chassis

Michael's legacy continues to live on, as this year's chassis is the Exact same as spyder's (with a few modifications to the electrical board)

Since we stuck with all CTRE components, we removed a lot of excess rev specific electrical components that were required and simplified the whole electrical board down significantly. The reasoning behind the 26*26 chassis was because we had already made it before, the upside down electrical board from last season was a positive experience for electrical and pit crew, and it saved me time on CAD as it was just me doing a good majority of the design. (So I get to skip a pretty time-consuming part of the design). We also exclusively used krakens with powerpole adapters to minimize the wiring, and it worked out very well.

Elevator

First concept of the elevator, originally designed to be sideways as it was seen as the easiest to package within the 26*26 frame. The goal was to simplify the placement of coral on the reef, so the initial thought was to keep it as simple as possible with an ikea shelf on an elevator. Keep in mind how the carriage is elevated where it extends out of the elevator, and there's only 1 moving stage

After the first design discussion, the decision was made to swap to coral placement through the middle of the elevator because... umm well I hate to admit it: because it looked cooler. From a table of differences we made between the 2 elevator designs functionally both were the exact same. We chose cascading over continuous because it is faster than continuous going up, and it would be significantly sturdier than a continuous elevator because of the constant ratio of overlap between the stages. I also originally had each side in sync with 2 krakens on either side with a chain driven 1st stage to cascade the elevator, but it was not possible to package. I added a 2nd moving stage to maximize overlap so it would be sturdier when moving up and down. (and it happened to give us enough height to reach the barge...)

A few packaging challenges (namely the trapdoor, the space claiming for the cage, and the electrical board) forced me to abandon the tried and true way of using pre-made gearboxes from vex and actually for the first time in the team's history make a custom gearbox.

The next problem to figure out was how to support the elevator. I settled on copying 148's 2018 robot which utilized cross-beams to support their elevator. Having the poles attached parallel to the elevator would support it latterly, but by offsetting the poles, it also provides torsional support which fully ensures this elevator remains stiff under the high stress it undergoes every match.

The cables were not cadded in as it would've been simply a waste of my time. I also wanted to utilize an iges chain to route the wires in a cleaner way, but the additional weight and routing required made it a challenge not worth tackling given the time we had.

Elevator Gearbox

Recalc Link (opens in a new tab)

Mechanism Calculator Link (Set to maximum efficiency) (opens in a new tab)

Elevator calculations were tested with a safety factor of 2

The mentors weren't a fan of the pocketing I did on the gearbox, and at the time we didn't have the capability to pocket aluminium, so I reverted it back to its chunk of aluminium. I also added slots in the mounting for the gearbox to compensate for any holes that were slightly off to keep assembly going smoothly. It's important to note: These gearboxes were designed for a cnc to machine them. Since we didn't have the capability at the time, the efficiency of the gearbox suffered because of slight deviations from the exact dimensions of the gearbox since it was cut by hand by machining. (They still did an amazing job though, it was amazing to see it working)

The final gearboxes that were put on the robot were probably at 50% or lower efficiency because of the slight deviations in the bearing placements. Because of this, the math didn't exactly take this into account and the actual gear ratio should've been a greater reduction to be able to backdrive the whole elevator without any power. Another thing I learned from the assembly of this gearbox was the sheer difficulty to do so. By having screws going through the whole gearbox and frame it created an annoying experience to put this together because of the restrictions of having limited space to work with in that tiny cubical in the frame to fit any tools in there.

Carriage

Similar to many of the other things I've designed, I always find a way to take inspiration from team 254. I will happily admit that a good majority of this robot was heavily inspired by 254 because I love their team. In this case, the carriage was pretty much a modified version of 254's 2023 robot to work for this year's challenge.

I started out with modeling a basic carriage with the dimensions that it would have on the outer walls to fit everything in such a small space. I learned very quickly that this was going to be a packaging nightmare as I had to fit 2 krakens in the given 6.5 inches.

It was impossible to use a pre-made gearbox so I had to make a custom gearbox for the pivot of the gooseneck, which ended up being the most complicated gearbox I've ever made and a real challenge to create.

I eventually figured out a way to fit both krakens in the small space I was given, and well, if this isn't the definition of tight packaging I don't know what is.

This carriage is the single most complicated thing the team's ever built in its entire history. To make the gearbox work we had to shear the ends of a couple gears to keep a stack of 3 gears (which is 2 inches side by side) in a 1.5 inch space. Along with the packaging challenges, the bearing loads on the sides of the carriage were also carefully looked at to ensure that it could handle the immense loads that would be on them.

The front facing bearing hubs were repurposed from the robot in 2 months but modified to be easier to make and more structurally sound (and were printed in carbon fiber). I also had to design it where we could custom cut the axles for the hubs and to ensure that the bearings (they were thrifty ones) would not lose any of its free spinning ability through a loss of energy from friction caused by rubbing against the sides of the carbon fiber hubs. The screws for attaching the carriage plates together had to be countersunk into the aluminium to prevent any rubbing against the 3rd stage elevator frame. A final addition to the carriage was the churros going across the carriage. These helped in lateral loads and slightly in torsional loads as well (though mostly the aluminium tubing on the outside and the side facing bearings did most of the work there).

Carriage Gearbox

Recalc Link (opens in a new tab) (The actual carriage gear ratio is 61.36:1, but I can't find where I actually calculated this ratio... I'm assuming I did it through the JVN calculator which would explain why I don't have documentation on it)

Similar to the other gearboxes, I started with a master sketch that consisted of a layout of the gear meshes and bearing locations. The distances between the gears were calculated using the WCP gear calculator (opens in a new tab).

The packaging on this gearbox was insane. On top of shaving off gears, the hub at the top that connects one side of the gooseneck to the hex shaft had to be shaved off so the countersunk screws wouldn't hit the 48t gear below. Truly a massive design challenge that really pushed all the subgroups which I think was a good thing. Making something complicated like this shows what our team is truly capable of making.

Gooseneck

Initial master sketch (we originally had it planned where the coral would be placed through the far side of the robot)

Draft of a front facing outtake that was decided upon for packaging reasons as the entire front of the robot would be taken for the cage

Krayoncad examples of what a possible algae in barge intake would look like with a 2 stage elevator

This design is what initially created the name "gooseneck" (which I absolutely hate). The motors were originally on the gooseneck as counterweight to make it easier to pivot the arm as the CG is way closer to the pivot point.

Inspired by the rembrandts, another alternative to the gooseneck was this octopus design that was made to accept both algae and coral by extending outwards and inwards passively with springs. This was not explored further as we simply did not have time.

This was the first version of the gooseneck (literally copied off a robot in 3 days) and was left in the CAD model rotting for a full week.

As soon as the rest of the robot was finished, I quickly adjusted the gooseneck to match compression that was tested in prototyping and to ensure it fitted between the elevator

In this final version of Mark I had the belts and reverse gearing and was slightly adjusted to account for the fact that I forgot to order belts... which explains why it doesn't look like a semicircle anymore. I had to work with the belt lengths that I had.

Climb

The climber was the single most frustrating subsystem on this robot as it took up so much theoretical space that I had to overengineer and package all the other subsystems on a guesstimate as to how much space the cage would take up in the robot. Just look at the space claim I had for the robot (Blue is for the cage).

Climber Mk I

Oh boy, here we go.

Let’s start at the beginning: our original climber’s inspiration came from team 4481’s testing of two clips connected to rubber bands that were able to latch on to a pole of the deep cage (https://www.youtube.com/shorts/9DLJQti0I8o (opens in a new tab)). This idea was appealing because, with the rubber bands pulling the clips to their closed position, it was a one-way door, effectively trapping the bar once you got it inside.

The idea came up that, for the best chance of climbing the deep cage, and to be able to climb easier, we should be able to climb no matter the orientation of the deep cage. As a result, this ended up being the first iteration of the climber: This was dubbed the “Triple U,” and could grab onto the deep cage’s middle bar (when it was at a 45 degree angle) or grab onto two sides (when the cage was in a horizontal position). The sides of the climber would guide the cage, whatever orientation it was in, towards the clips. This was eventually carved out of lexan for prototyping, and seemed to work fairly well. The reason we chose not to settle on this was because it seemed like overkill: did we really need this many clips? Plus, there were some concerns about alignment: what if the middle bar got stuck on the left side? Although the climber was designed to handle these situations, and could theoretically hold the robot up on just one set of clips, we eventually decided that it wasn’t worth it.

This is where some other ideas were suggested. One in particular was appealing since it only required one “clip” per gap, and would latch onto two sides of the cage every time. It looked something like this:

The ready position (before the deep cage comes in) is on the left, and the closed position is on the right. The real problem here was figuring out how we would lock the clip into the closed position once the deep cage comes in. Ball plungers seemed like the best (and only viable) idea, but we ditched the concept since, as it turned out, they couldn’t hold nearly enough weight. A pivot, as can be seen in the same picture, was another idea that was brought up, but turned out to be of little use: if anything, it hampered the orienting ability of the shape.

But this “Double U” seemed quite promising of a shape, as it could orient, with the help of the center spear-like shape, any cage into the proper latching position. Substituting with the clip pairs and rubber bands that worked quite well previously, our Mark I climber, affectionately named “The Trident,” was almost complete.

There were only a few things left to do:

• Move one set of clips to the opposite side so they don’t clash
• Get rid of the pivot and bearings
• Adjust the shape to accommodate other parts of the robot
• Make it look nice

And there you have it, our Mark I climber, primarily used at our first two competitions.

Climb Gearbox

Recalc Link (opens in a new tab) (I used the mechanical calculator to get the exact gear ratio for maximum efficiency, unfortunately lost the link)

I never explained how I actually do these calculations so I decided I'll show an example with the climb. Imagine Stingray getting ready to climb off the cage, so it's in climbing position as displayed in the picture.

In this case, since we are lifting the robot with a pulley, The CG (marked in yellow) is right next to the point where the robot is going to lift (or more accurately rotate).

To actually do the arm calculation, I split the 2 parts of the robot into the climb (marked in yellow) and the robot (now considered the "arm" for recalc in green). I assumed that the yellow (climb part) would be stationary and the robot would pivot around the climber.

So the calculation I did in recalc is basically calculating this motion, considering the "arm" as the entire weight of the robot. It is kind of weird to think about because were lifting the arm from the arm itself (the pulley) but after a bit of thinking you'll see that it makes sense.

Stingray Mark II

Elevator

From the very start of this season, the thought of making a belt driven elevator has always existed. It's because with cables you can only pull, while with belts you can both pull and push, so you can drive the elevator both up and down without leaving it to gravity.

As you can see, it was incredibly painful to watch this slowly fall down. It was costing us precious seconds that couldve been used to do more cycles.

So naturally, we (Mr.Davis happens to equally be a big fan of them) looked to 254's 2023 robot's laterator to implement into this robot.

We analyzed this picture so many times to understand how the belt cascading elevator worked

Master sketch for how the cascading effect worked on a belt driven system (Took me a frustratingly long time to understand this). It basically acted as a push and pull system for bringing the elevator up and down. Similar to how in movies pirates go heave ho on the sails to bring them up and down.

I tried my best to highlight how it works... I don't blame you if you don't understand it...

Brand new elevator pieces THAT WERE DESIGNED FOR THE CABLE ELEVATOR. WE HAD TO CREATE A BELT DRIVEN ONE WITH AN ALREADY POCKETED FRAME. Also Special thanks to Brody's dad for the beautiful pieces.

This elevator was the single most stressful thing I've ever had to do in my life. In just 3 days we had to figure out how to convert the elevator we had already made (the new pieces WERE ALREADY CUT) into a belt driven one. Special thanks to Mr.Davis for beating his head as well to solve all the crazy packaging that had to happen for this to work.

The top was swapped from a closed to open layout to route the belts and to help the goose neck go even further up. You can also see a closeup of how the belt mounting worked. These belts were stripped of a garage door opener and as such, was not a full closed loop. This means boss had to use his bare hands to pull the belts as hard as possible and lock the belt in place with the mount plate onto the aluminium.

This elevator was nothing short of an engineering miracle. In just 3 days, Mr.Davis and I managed to convert the cable driven elevator into a belt driven while only adding 8 new holes to the entire elevator. I would NEVER IN A MILLION YEARS suggest anyone to ever go through this again. It was incredibly stressful but the end result made it even more worth it. Many of the students had absolutely no clue how the packaging and insane fittings that were made for this belt elevator. It's something to truly marvel at, managing this in such a limited position.

Oh fun fact: We were the only team in FRC to have a cascading belt driven elevator this season (We were the only ones crazy enough to do it lol)

Carriage

The carriage was heavily pocketed to make the entire elevator as easy as possible to lift up and down. This would've significantly helped with the speed as well. One side was done with Inspire, the other side was done by myself where I eyeballed the proper pocketing for proper stress transfer.

Example optimization through motion analysis. 48% lighter, 57% stiffer.

I actually made a full video on how I did the optimizations for the carriage pieces.

Cut pieces (special thanks to Brody's dad again)

Gooseneck

Nothing special about the gooseneck iteration, It was more of adjusting the algae holder to make it easier to pick it up, and then adding a wall on the sides of the gooseneck to prevent coral from getting stuck hitting the side walls. Oh, and also a weird curve to prevent the wires from the carriage getting torn apart by the walls of the gooseneck.

Climb

I'm going to let ryan talk about this because he made the mark II climber

Takeaways

I think I'm going to change it up and leave some advice for you guys.

There are as many truths as there are people.

Over the past four years, I’ve grown alongside this subgroup in ways I never expected. And if there’s one lesson I’ll carry with me forever, it’s this:

Always stay open.

Open to new ideas. Open to new perspectives. Open to learning from the people around you, whether they're seasoned veterans or first-day freshmen. My biggest lesson came from people younger than me: because I chose to listen.

Every person in robotics sees things a little differently. Thinks differently. Explains differently. And that’s what design is truly about. Real design isn’t just your own vision: it’s the ability to create something greater by seeing it through someone else’s eyes.

As long as the Sun, the Moon, and the Earth exist, everything will be all right.

Build season can throw some nasty curveballs, especially when it comes to robot design. But it's not worth it to show your stress to others. Instead, be the chill person in the room. Crack a joke (just attack boss), and figure things out one step at a time. I've told students on the team everything's fine knowing full well I didn't even start a sketch on a part that I'm supposed to have done in 1 hour lmao. (Maybe not a good thing from a communication perspective, but you get what I mean). Having a chill vibe is contagious, and it really helps during build season. At the end of the day, robotics is just a snippet or your life, don't let it control your life. Balance your time.

Sukhesh's final words of wisdom

To the students who will come after me, who may even never meet me:

CAD is hell. Satan might as well have put his name in the credits (bold font, extra big) of all the CAD softwares created. It’s definitely painful at times. (Especially when deadlines exist)

And yet, somehow, it’s beautiful.

Because behind the hell of designing things is something way more important than design.

It teaches you how to stay calm, how to take criticism, how to communicate with others, how to think like an engineer... and most importantly:

How to keep moving forward, no matter how many absolutely gut-wrenchingly atrocious problems come your way.

And as weird as it feels to say this: I guess it’s time for me to do the same.

Watching a blank canvas turn into what it is today... all I can say is, it’s been one hell of a ride.

And in typical Sukhesh fashion, I leave you guys with no instructions, no expectations.

What you do with this canvas is now in your hands.

It’s your turn. Do something insane with it.

Break things. Try bold ideas. Have fun.

Just… don’t let it stay the same.

Take care of this subgroup.

Make it yours.

P.S. If boss's blood pressure doesn't shoot to instant cardiac arrest levels at least once during the design process, you're 102% (with a 2% margin of error) doing something wrong