X-SHARC #6838 | Build Blog 2023

Strategy Guide

Hello everyone! My name is Berra, and I am here today to give you an insight into our strategic plan for CHARGED UP. There is one rule we always keep in mind while making our decisions: Golden Rule #1 “Keep It Silly Simple (K.I.S.S)”.

First, we had all members fill out a copy of 6328’s worksheet. Later today, we had a discussion with the entire team, to brainstorm about different takes on the game.

Afterward, in a separate meeting with subteam and team captains, we decided on our robot’s strategy for the autonomous, teleop, and endgame periods under three categories: must-have (things we will definitely do), nice to have (things we will try to add after the basics) and explore (things we will do in the upcoming regionals/process). Here is what it looks like:

For the robot’s main strategy:

  • Must have:

    • 65x65cm frame perimeter
    • Center of gravity on the low back of the robot for not tip over
  • Nice to have:

  • Explore:

    • 60x60cm frame perimeter

For the autonomous period:

  • Must have

    • 1 cone scored on the low row + docking
  • Nice to have

    • 1 cone scored on the low row + docking & engaging
    • 2 cones scored on the low row + docking & engaging
  • Explore

    • Engaging automatically using gyro feedback

For the Teleop period:

  • Must have:

    • Scoring cones on the middle row
    • Cone pick-up from the human player upper shelf - considering it is almost the same height as the middle row cone placement
  • Nice to have:

    • Scoring cones on the high row
    • Cone pick-up from the ground
  • Explore

    • Picking up cubes
    • Storing 2 game pieces (referencing to the rule G403)

For the Endgame period:

  • Must have:

    • Robot is docked & not engaged
  • Nice to have:

    • Robot is docked & engaged with further driver practice
  • Explore

    • See if autonomous engaging is viable with 3 robots

There were some debates about certain decisions including; whether we should pick up cones from the ground or from the shelf, be able to access two game pieces, so on and so forth. We decided not to attempt solo links; since it requires us to use both game pieces - making the system more complex.

Some of our concerns about having an HP-only intake are about cubes and cones creating a wall in front of the wall, similar to some cases in 2019. This is what caused us to lean more toward a ground pickup for now. We included both in our strategetic plan to see which would make more sense based on our prototypes and the community’s insights.

Additionally, different to previous years, we decided to make a more precise and detailed strategy for the game. We are mostly inspired by the level of strategy detail in 254’s binders. For example, criteria like “climb<8sec” for last year. Because we didn’t decide on these, we didn’t include such details for now. We will hopefully be posting a more detailed version of everything tomorrow.

Drivetrain Update

For the drivetrain, we have already had a 70x70 cm drivetrain for MK3, MK4, and MK4i swerve drives. In order to make 3 robots fit on the charge station, we reduced it from 70 cm to 65 cm. We still have to add hole patterns until tomorrow noon. We plan to send it to manufacturing on Tuesday.

Currently, it is still exam week for our students. So, our progress is a bit slow for now. We hope that beginning from Tuesday, we will pick up our pace.


Strategy Update

Welcome back, everyone! We had certain questions in our minds with the previous strategy, so we decided to make arrangements for the current one to fit our goals for the season. The main problems for us are the cycle times and the challenge of putting objects in the top row. That’s why we made a priority list for ourselves to focus more on the order of our strategic plan.

#Priority List

2 game pieces, cones → mid, cubes → both

  1. Dedication.

  2. Have a functioning swerve chassis that complies with all the rules.
    2.1. Have a 65x65cm frame perimeter to leave room for alliance partners.
    2.2. Have securely mounted bumpers early in the season.

  3. Be able to pick up at least one of two objects to have a functioning auto (with a charge station).

  4. Be able to get on the charging station without engaging. Both in the endgame and in auto.

  5. Regardless of which game pieces we are intaking (cube, cone, or both), have a single intake.

  6. Be able to score cubes to the middle.

  7. Be able to score cubes to the top.

  8. Be able to score cones to the middle.

  9. Get driver practice.
    9.1. To be able to do the cycles as fast as possible.
    9.2. To solo as many links as possible

  10. Auto-align the nodes.

  11. Be able to score cones to the top cone. (More of an exploration.)

  12. Explore Auto-engagement on the Charge Station

As listed in the priority list, we switched to focusing on the cubes after our discussion, simply because they are easier to manipulate. Also, we believe that we can get away with a single-stage elevator, both placing cubes on all levels and also hopefully placing cones on the middle row. We believe this will be a lot simpler to handle. We have put the second game piece further on the list of tasks - since we will be able to pick up the two kinds of game pieces anyway. We will work on prototypes and mechanisms to place game pieces on the upper rows in the upcoming process, but our strategy is locked for good as of tonight.


Since we locked our strategy, we made several meetings with the CAD members. We decided on general robot structures which get along with our strategy.

Robot Architecture

Inspired by 3847’s idea of putting a slider on a slanted elevator, we tried different sketches to work out the geometry. Overall, there are 3 types of robot structures we discussed:

  • a long single-stage elevator with an intake parallel to the ground
  • a shorter 2-stage elevator with an intake parallel to the ground
  • a shorter 2 Stage elevator that is raised above swerve modules with an intake perpendicular to the elevator.

Single Stage

This sketch explores how a single-stage elevator has to be sized to reach all the middle cone rows. For the third level of the cubes, we might need to give them a bit of a thrust to get across.

For this sketch, we have to figure out how to put a slider at an angle to the elevator to make sure the slider itself is parallel to the ground.


  • Not too risky for the strategy.

  • Get along with the 5th and 7th points on the priority list

  • Be able to score cubes to the middle.

  • Be able to score cones to the middle.

  • Very easy to build and control.


  • Because the mechanism is too tall (125 cm), we might have to limit the robot’s acceleration in order to not tip over.

  • The CG might be too high up.

  • There might not be a good place to place the gearbox for the elevator.

  • It Might be hard to incorporate the slide.

  • Smaller elevator as it has to fit between swerve modules. (Although, this might have some advantages in itself as well.)

Low 2 Stage

This sketch has a 2-stage elevator and reaches both the middle and top rows for cubes and the middle row for cones. Still, the complexity of the slider being parallel to the ground remains.


  • It might be able to place objects in both the middle and top row which is further in the priority list.

  • The overall height from the ground is ~81cm.

  • A better CoG overall.


  • The added extension might cause stability issues.

  • 2-stage elevator is slightly harder to build.

  • Offers slightly better mounting for the elevator gearbox, but still not ideal.

  • Smaller elevator as it has to fit between swerve modules. (Although, this might have some advantages in itself as well.)

High 2 Stage

This sketch is basically the previous elevator raised above the swerve modules by 17.5 cm. This enables us to have a lot wider elevator. One difference is that this sketch uses a slider that is perpendicular to the elevator different than others. This will enable us to keep our design simpler but it makes it harder if not impossible to score high cones with this design.


  • It’s putting the object in both the middle and (maybe?) top row which makes us further in the priority list (till #10).

  • The height from the ground is 104 cm. (Taller than the second option but still very good.)

  • The CoG can still be very well-adjusted on this one.

  • Can be easier to intake the objects as the intake will be at an angle. (This might turn out to be a disadvantage as well.)


  • Intaking might actually be harder.

  • We are losing the practical length of the elevator due to the perpendicular intake.

  • The slight complexity added by the 2-stage elevator remains.

Intake Prototypes

Other than our elevator system we started our intake prototypes. There are 5 students who are designing intakes. While they are all designing one, there are only two that were sent to the router. The only difference between them is the number of wheels. The design should allow for some adjustability for us to take some measurements for the ideal compression. We will be testing it out tomorrow.

We will be making more intake prototypes soon. However, some of them might get postponed to next week.

Also, here is the current protobot on the field for trial:)

Feel free to make comments and recommendations about our elevator and intake mechanisms.



I am Zeynep, a new mechanics and electronics member of team #6838, and this year, I hope to be a part of our Build Blog writing crew too!

Today, we met up for the first time after the kickoff to build our first prototypes and work on our programming. At the end of the meeting, we all agree that this was the most productive we could have been in our first meeting.


Today’s most important topic for us was building intake prototypes. Just after the kickoff, many of our team members have started to sketch their ideas on onshape, and today, we were able to build 2 of those prototypes.

Intake Prototype 1

The first prototype was an intake design with inspiration from FTC Powerplay robots. Even though it was designed mostly to take cones from the ground, it still is practical for the cubes too. Moreover, I can totally say that this design fulfills our golden rule #1: Keep It Silly Simple (K.I.S.S).

It is a pretty straightforward mechanism, using two parallel plates with star wheels and 30A compliant wheels to grab the cones.

We consider it a successful design even though it needs more work. We will most probably keep iterating this prototype. You can view our test videos here.

Here are our findings:


-Simple to build, can be very lightweight.

-Easy to iterate throughout the season, a very modular design.

Hard to beat, with a single motor to power it to pick up cones and cubes off of the ground.

-Compliance might be useful with something like surgical tubing to get a better hold of the cubes.


-Not sure how optimized it could be to hold both game pieces well.

-Can’t currently hold game pieces when lifted off the ground.

-We are not sure if the star wheels are the best way to go here. It feels like different wheels might be better.

-Can not intake from a large area, width-wise. We will also try to implement something like 254’s 2018 intake to see how well that would work. (This might be compensated with driver practice, but we would prefer a wider touch-it-own-it intake.)

Intake Prototype 2

The second sketch, which is also an intake prototype, was inspired by FTC GEarheads Team #16460, whose robot you can further observe from here.

Making this prototype was a more challenging task. This prototype aims to tip over all cones to intake directly, so that we can intake both tipped and upright cones.

There is a front roller with star wheels to tip the cone over and when the cone is in, the belts raise them to whichever mechanism requires it. We initially designed this prototype to use the roller claws on the sides to help carry the cone upwards. However, due to time and resource constraints, we could not test this.

We had some troubles making this prototype function in a stable manner, however, we also think that it is not a problem that can’t be solved. Based on our robot architecture sketches, we might improve upon this idea, but it also seems a bit unlikely. However, we believe many top tier teams will have similar intakes that will use this principle, so we are happy to hear feedback or other similar principle prototypes.

You can view our testing videos here.

Our takeaways:


-Can be great to pickup cones that are upright, and tipped over.

-Shows great potential for improvement, don’t get fooled by the videos.

-If tuned, this design might be very beneficial in getting cones in consistent orientations.

-With compliant side rollers, it might also pick up cubes. (This might make cones easier as well.)


-A bit bulky, takes up too much space in the robot.

-Not sure how it would also pick up cubes. (Might need to make it spring-loaded, which adds complexity.)

-The bottom of the cones might cause some problems when intaking, unlike the round bottoms of FTC.

-Not sure how well it would pick up tipped over cones from the ground, as that requires side rollers.

-Again, not sure about star wheels. (Though, we are not sure if they made it better or worse for this prototype. We did not have the time to try other options.)

At the end of our first meeting, of course, neither of our prototypes are perfect, however, we gained some good insights that will drive our robot design which we will probably release some good updates tomorrow. We also worked on programming and also got some new tools in the shop, but those topics are beyond my scope for now. So, expect updates on those tomorrow as well!

Until then, thanks for tuning in. Please let us know if you have any feedback or questions.


This weekend was very efficient for us. The CAD team pulled an all-nighter at Nitrocare’s office, a generous sponsor of ours.

While the ultimate goal was to finish the robot assembly without the intake, we could not finish the whole thing. However, we got a lot done! Most parts are already sent out to our manufacturing sponsors. We hope to get them by Wednesday.

Robot Progress


Hands of to Mohamad, our elevator lead! He did a fantastic job on this.

We have a slanted elevator with 55 degrees from the ground. Since the previous post, the biggest change is the width. We removed the elevating superstructure and narrowed down the elevator so it fits between MK3s. This option also gives us a good room behind the elevator for the gearbox. Still, there needs to be a supporting beam on the front of the elevator. For this, we are considering three options:

  • Carbon fiber tubes with 3D printed clamps (1323, 254 style)
  • Aluminum tubes with 3D printed clamps (Protopipe, 118 style)
  • Aluminum tubing cut at a 45-degree angle for easy mounting.

While the easiest would be tubing, we might want to go with either tube option to mount the elevator to the outer chassis at an angle with minimal weight.

Elevator Gearbox

We are currently running 2 Falcons on a 17:1 reduction. This should be very fast and still have enough power to manage all the lifting. The assembly of this gearbox is a little finicky though. It will be sandwiched between 3D-printed backings for the elevator and also be supported by the chassis using standoffs. Honestly, this is nowhere near the optimal scenario, but we could not come up with anything better for now.


The carriage was also updated from a rectangle made up of tubings to use an approach similar to this thread:

Elevator Carriages of Increasing Compactness

The top and bottom extrusions will use 3D printed tube plugs (a very similar design to crush blocks by 5119)

Overall this will give us a large enough carriage. The ends of the carriage have fingers, so the slider can be taken of with 8 bolds. This will be super useful as we iterate the reachor mechanism.


The slider as it is currently is made up of 25x25x2mm box tubings stacked so that they make up a horizontal elevator. This will be belt driven by HTD 5M belts and will be run off of a Falcon with a 64:1 reduction. The sketches on our slider are very modular, so if we decide to change up our elevator later on, we can easily adapt our slider to it.

Slider currently has two different sheet metal mounts: one parallel to the ground, and one at an angle to the ground.

Things to add/consider:

  • Gearbox assembly & mounting. (Mostly done, just couldn’t make it to this post.)
  • Lightening pattern for gussets.
    • We probably won’t be able to mill out custom patterns on our tubings for the next week, so, we will just keep the tubes as they are.
  • Intake mount plate and intake geometry to be within the frame perimeter.



Also, another strong candidate for mounting the intake is to have the intake arms pivotable and start the match wide open up against a hard wall until the elevator moves up and gas shocks bring the intake to the ideal compression. The folding action is very similar to 971’s 2018 intake, just much simpler, and uses gas shocks with hard stops.

Having pneumatics might be helpful to have multiple intake positions like Triple Helix, 2363, but we might stick with just using gas shocks.

For the prototypes, we designed 2 different versions. The differences are just the wheel types, arrangement, and compression. Some students will be testing these prototypes this week while we wait on the main parts and robot assembly.

For now, we are trying to find a good compression and a good geometry to handle both game pieces. Yet, we still have to figure out how to assemble them on the robot.
Also, having the intake pivot down or pivot around the slider gives us the ability to reach to the high cones for scoring. While this is down on our priority list, it is nice to have the robot be mechanically capable if we want to go down that route later in the season.

Robot on the Field


Slider Update

Since yesterday, we got our slider design up to a point where it is ready to be manufactured. Although this is intended to be the final version, there might be a couple of revisions based on its testing.

I will let the photos speak for themselves:

Technical Details:

  • The design uses our old 30mm wide HTD5 belts from Guido (our '22 bot). We will have to cut those belts and clamp them. The design also has a slot (seen below) to route additional belt length around itself and maybe clamp down the folded pieces as well for added strength. While this probably should not be necessary, it is nice to have backup options in case things fail.

  • The design uses Thunderhex bushings, however, we do not have Thunder hex to go with them. We will probably turn down some hex shafts to make sure they fit.
  • We also designed an angled intake mount in case we want to put the intake at an angle. This is still under development and may not be used at all. (The sides are not designed yet.)
  • The Sport gearbox has a ratio of 64:1 and a 1:1 belt transmission. This should be plenty of power and speed.
  • The system as it is 3.148 kilograms (~6.9 lbs) but the CAD does not have the materials and weights assigned for the belts, pulleys, and also bearings.

Looking for feedback!

Please let us know what you think! We do not have any members experienced with linear systems, so any feedback would be highly appreciated.

We'll keep you all updated.



Programming Progress

Hi everyone,

It’s Yanki from X-SHARC. I am the co-captain of the team and am interested in programming and designing parts of the robot.

Today, as the programming team, we all updated our devices’ libraries and firmware. Right after the updates, we had the swerve code prepared for the season and tested it out to make sure on our old chassis.

Besides that, the rookie programmers began their research and subsystem codes. Our further plans for the next 4 weeks are to make sure all the commands work fine and have some driver practice after implementing an adequate autonomous code.

Also, we want to use the AprilTags and the reflective tapes in our vision processing part as well. Not sure about which co-processor to use this season considering the AprilTags might cause problems processing them.

See you in the next programming post update :slight_smile:



Yesterday most of our parts arrived so we started to assemble our robot. They are all machined 3mm, 6mm aluminum, and 1.5mm steel.

Also, for the tube assembly, we waited for our programmers to migrate our drive base code to 2023 (which you can read more about in the last post). Having successfully done that early in the season, we will start the chassis assembly Friday.

Manufacturing Update!

Our CNC Router finally arrived! We are still waiting for the school administration to set it up and do all the paperwork but we will be using it hopefully beginning next week. Our drill press and belt sander also arrived last week. While we have the belt sander up and running, we are still waiting for the drill press similar to the CNC router.

Slider Tubes Manufacturing

Also, we were finally able to use our mill to square our and drill our parts. We have manufactured 1 of 4 tubes for the slider and we will finish them off today.


Programming Update

We worked on commands and autonomous command groups today with the programming team and worked on outlining the new year’s robot code architecture. We are working on implementing PID controllers for the elevator subsystem, alongside with limit switch, to be able to control its position. We want to run a hex-bore encoder (cancoder with hex-bore housing) and also check internally if the encoder is down and switch to Falcon’s integrated encoder in case of failure automatically. This is done by other teams but for us, it is quite experimental. We are looking forward to what our programmers can accomplish!

Programmers will be researching more on AprilTags, reflective tapes, and vision processing (Limelight or Photon Vision running on Limelight 2+) after completing the autonomous commands and testing their code.

Assembly Time!


Today we cleaned up our MK3 swerve modules and assembled them to the new chassis. One module showed some resistance on its driving gears, but a little cleaning and filing solved it. Still, MK3s feel like they have served their time so we are looking forward for our MK4 modules to arrive.


Also, we did the missing rivets on the first stage of our elevator. Also, we assembled the carriage. We still have to wait for the bearing blocks though which will slow us down.

Also, one of our senior programmers wanted to learn some CAD. So, he did the supporting tube for the elevator and we manufactured it in-house. Sadly, I do not have any photos of it, but we should be able to post them around tomorrow.

Elevator Gearbox

We also assembled our elevator gearbox and wired it up to the 2022 chassis and tested out the motors. Everything seems to be working well for now.


We continued milling out the parts for our sliders. While we got a good portion of them done, we messed up two pieces. So, tomorrow we will be milling new pieces. Regardless, we have put together the Falcon + Sport gearbox and also wired it up, and tested it. Here are the photos:

Intake Prototypes

As we share before we have 3 types of intake prototypes (which are different compression amounts and wheel arranging).

Today we had the chance to try only one of them. From our prototype, we saw that our compression should be more than we think. We made several changes to try out different compressions. You can view our testing videos from this folder.
(The link is live, our students will be uploading the videos once they have the time. So, please try again a couple of hours later if the folder is empty/or you want to see more videos.)


Build Progress

This weekend we made some good progress on our build. We couldn’t finish the entire elevator, but other than that, we finished up our chassis, elevator base stage, gearbox, and (mostly)slider.

Bearing Blocks

For our elevator, we made metric versions of the bearing blocks from Thrifty Bot. Even though we couldn't rock your bearing blocs due to metric stuff, thanks for making such a great product!


As we are using 25x50mm tubes (which is the closest metric tubing to 1x2 in), we redid some dimensions and used metric bearings and shoulder bolts. We received our sample bearing block from our CNC sponsor. However, the holes for the treads were a bit loose. We redid the dimensions for the holes and we will be receiving the new units within the next week.


We received our belly pan and started assembling our elevator. In order to mount the elevator gearbox, we had to disassemble our swerve modules on the rear side.


We want to test out our slider as fast as we can, that’s why we made that in our milling machine in-house. Since we are not very experienced in using the mill, we made several mistakes with the holes which slowed us down a lot.

For the slider, we made custom bearing plates from 3mm aluminum. For now, the slider seems to move smoothly and tolerances are good enough. We will finish the assembly, attach the belts and assemble them to the carriage. The only thing left is to put the rounded hex shafts through the bushings and clamp down the belts.


What took our time the most was assembling our base stage and the elevator gearbox. The gearbox was assembled to the robot by several (many) threaded rods going through. We also 3D printed the spacers needed in shorter places to make sure the lengths are accurate. We also 3D printed an angled piece for the slanted elevator to rest on when it hits the ground.

Well, even though things seemed to be great in the world of CAD, we found out that our gearbox coincides with the chassis tubes. After fixing those up, we also want to make a protector for the gearbox as it is hard to service during competition. Adding to that, the threaded rods in the back that hold the gearbox in place are a little bit hard to reach. That’s why they can cause us trouble during matches when fixing something, but they are within the frame perimeter and well-protected. So, we hope they will be safe inside. We also cut down and milled some tubes to support the elevator from its sides.

Let us know if you have any questions or comments!

We will be meeting again on Tuesday to continue the assembly. Until then, we will be revising some things in CAD and getting some rest.



Looks amazing! I love when teams adapt Thrifty designs to fit their needs. Keep up the great work


CAD Update

Finally, we had the time to work on some stuff that we always pushed further down the calendar: Limelight mount and swerve guards.

Both designs are intended to be made out of 1.5mm (~0.059 in.) steel.

Limelight Mount

Swerve Guards

Both mounted to the robot:

Let us know if you have any suggestions or comments!


Don’t forget to take care of your body and stay healthy! (not that I’m doing that great at it myself, but, yani, take good care of yourselves, get enough sleep <3


Here’s my suggestion - add holes for handles in the tops of those guards. That’s what we did for our summer swerve, and it was a great decision.


Holy wow y’all are fast! Very impressed.


Thanks a lot! What material and thickness did you make those out of?


The guards are 1/8" 5052 aluminum.
The handles are McMaster-Carr


Why do you have so many cross support rods on your carriage? Looks heavy and what I would think is unnecessary

Love the design. Might have to borrow a few things…


Hi! What’s the angle of the elevator?

1 Like

Hi, we put our elevator at 55 degrees.

Here are some other dimensions for the elevator;