Welcome to 6381, Red Raider Robotics’ open alliance Thread! Here is where we will share out process for you all. Connect with us with anything that are interested in and any questions you may have. We want to continue to foster the ethos of FIRST through effective coopertition and Gracious Professionalism. Share more, learn more, grow more!
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Looking forward to it! You all never cease to amaze 
Red Raider Robotics has been busy in the off season leading up to kick off on January 4th. We’ve built robots, connected with our community, and continue to grow each off season to be ready for another season of FRC.
This off-season, we focused on gaining knowledge on programming while working with Rev and CTRE Swerve setups using SDS modules.
First up, we have Darla
Darla was our experiment with using Rev Through bore encoders instead of CTRE CANcoders as well as a Navx 2 for our IMU. This allowed us to learn about the Rev system and how we can tune our swerve modules using that system as a whole. We used YAGSL as our base for programming Darla (Code)
We found that the Rev system was extremely fluid in using the Rev Hardware client, especially. In using this in tandem with the YAGSL base code, it worked flawlessly in Tuning PID. From a design standpoint, the Rev Through Bore encoders positioned on the SDS modules are easy to swap in the case of an emergency issue with them.
Next, meet Raptor
Raptor was our experiment in CTRE systems with Krakens as our main motors for the entire system on SDS modules. We did two version of code for Raptor:
- Implemented CTRE Swerve with Kraken Drive Motors and CTRE Library
- Implemented CTRE Swerve with Kraken Drive Motors and YAGSL
We found that we loved how the swerve generator UI through CTRE worked and created code with motor values pre-assigned. However, a little more PID was required, which is why we liked the fluidity of the Rev robot (Darla) just a tad more. However, with Raptor we did pull some of the vision systems from YAGSL as we have used those for a while and they are tried and true. PhotonVision has been our go to system for multicamera vision for AprilTags and object recognition. We plan to use a similar setup with an array of cameras in the upcoming season:
Last, we attended several off season events with new implementations of code with our robot, Valkyrie from the 2023-2024 season of Crescendo. In attending MROC, LRR, and TWIST in this off-season, we experimented with more PID tuning, pathing, and adjusting the functionality of our robot. We were able to increase the efficiency of our pathing for autonomous and increased our intake speed significantly, which increased our teleop efficiency. (Updated Code)
In other news, we spent time working on refining our skills in Onshape working with FRCDesign.org to train our new members.
Last year, we used 95A TPU wheels for our drive train. We specifically used this model for our wheels: TPU90A Tire & Hub for SDS MK4 Swerve Module
These worked really well, increasing our rolling coefficient of friction and increasing our driving efficiency. We did toy with Colson wheels, but it felt like driving on ice, so this wheel and hub combo were the perfect solution. One downside of this setup up is that is required us to pull off the main bevel gear and use a large amount of force to swap wheels each day during competition. In an attempt to reduce the stress of our pit crew and be able to even swap between matches, we looked at developing a TPU tread for the SDS billet wheel. We ended up with something that looked like this:
This design didn’t work because we assumed we could wrap it around using the correct geometry of the wheel, but this definitely did not work as we hoped!
We also didn’t want to print it flat so that the layer would be in the correct orientation to handle wearing down better.
We then decided to try out using the direct geometry of the billet and design a tread that is pre-wrapped in the orientation of the billet, plus it would print in the correct orientation to have stronger layer lines. The result was this:
Our resultant CAD is located here (Onshape). with several revisions to come! We plan to add more tread patterns as well as a structure that would allow our wheels to have more compression, leading to a better contact area with the ground, improving our wheel grip to the field surface.
Robot in 3 Days - 2025
We are participating as a Robot in 3 Days team this year. We will be streaming on YouTube on our channel Red Raider Robotics Team 6381. We are pleased to receive a Mini Sponsorship via AndyMark for our team. This a first for us as we usually take a large amount of time and are very intentional in our CAD Design process and prototyping that lead us to our final robot design. This adventure into the Ri3D realm will give us a chance to have a fully functioning robot quickly and to drive our prototyping process further and give our programmers a chance to experiment more rather than the “Sit on our hands and wait” while we design and build a robot. We are excited to also invite back some alumni to help with this process so we can also run our kick off process of brainstorming with the whole team in tandem with Ri3D. This is a first, so we will update you on this process to find out if this works for other teams as well.
We have some goodies prepared to get the ball rolling!
Upcycled electronics from our former mini bot and some new Rev Gears, sprockets, and brackets:
Some Rev Extrusion to try out (we usually make our own bars, but time is unforgiving for Ri3D)
After our success with Darla, we want to try out some Rev MaxSwerve Modules. Our rookie manufacturing students learned how to assemble modules by putting these together. We also salvaged some gussets from previous robots that may be helpful.
Keep up to date with our posts and let us know if you have questions or insights along the way in our process for this years Open Alliances posts! Good Luck to all of our fellow FRC teams. Thank you for FIRST Wisconsin and our network of FRC teams that make every event so much fun to be a part of and we learn so much from each other.
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Nice!
On Raptor, what is the component between the radio and the roboRIO?
It’s a 5 volt buck boost converter for the LEDs and Orange PI. Amazon.com: BINZET DC Converter Step Down Regulator 5V Regulated Power Supplies Transformer Converter (5V 10A 50W) : Electronics
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Day One Stream
So far, we have drawn up some general sketches. A few include:
- A “donut” method, in which there would be a hole located in the middle of the robot. By using this method, we would be able to attach to the deep cage straight through its center. However, due to the time constraint of Ri3D, this idea could cause challenges, but it my be an idea we can apply to our main FRC robot.
- Another potential idea to handle the coral pieces utilizes a stable pole so mechanics are not required.
- To handle algae, many suggestions were given. Some include: a curve that would clutch the game piece in a similar fashion to a hand, a curve that utilizes wheels to pull in the ball, and straight bars with wheels that can allow the algae to go through an elevator and into a shooter.
- A system using pneumatics
- A catapult design. This method has been implemented by teams in previous years, but due to the size of the algae, it cannot be easily applicable in this case.
As we discuss the logistics of how our robot will handle game pieces, our subteams have been working on a chassis. Design team decided to make the dimensions 26x26 inches. Its size needed to be larger as to avoid falling over when trying to reach higher up and to fit door constraints. They also designed a belly pan using ABS, which is easier to cut to shape, including a hole in the middle to hang from the deep cage (which takes into account the robot’s center of gravity to avoid tipping). Aluminum-6061 chassis gussets were also designed, and to avoid cracking the ABS, holes were added to make matching pairs of top and bottom gussets. Due to the arbitrary shape of the gussets, manufacturing team used a water jet cutter, making it easier to mount and cut the pieces as milling would require custom fixturing. Further, design team implemented REV Swerve Module wheels and REV bars for the main chassis, as the compatible components working together help to speed up the process. Programming team chose YAGSL Swerve Library for their data, which will control the drive train, or the motors controlling the wheels and rotation. This program is most effective with REV due to our team’s experience with it. Testing over the summer has allowed us to be more familiar with the program, making it easier to apply it to this project and allowing for smoother driving.
As we continued our process today, we began starting a rough draft for collecting our game pieces.
Our design team came up with a draft involving a PVC pipe to hold our coral pieces. This pipe and attached coral would be held by a cone. The cone would be clamped at the bottom to help with spacing, allowing us to attach to our robot’s arm in the future. The coral and algae would be attached to the same arm, which would pivot, and a servo placed inside of the arm would be programmed to grip it. An elevator would extend to any necessary height to score and even have the capability to drop directly into the net, eliminating the necessity to shoot the algae and have potential misses. This arm would also be able to rotate 360 degrees. The algae would be grabbed vertically to go through the elevator (lift system), and a ramp built against the elevator would allow it to drop it into the processor area.
As design attempted to create the idea in CAD, we had many complications. The PVC pipe was rotating too far down, hitting the bar of the elevator, so it had to be removed. A new idea that emerged using the claw manipulator originally planned for the algae. When the claw is straight up, it can hold the coral, and when bent inwards, it could hold the algae. It could still rotate 360 degrees, and a servo would be attached per claw while the whole manipulator utilized two in total. The bars in the elevator were REV max tubes, and baring blocks were installed from West Coast Products Cascade Elevator, which removes friction so the elevator can move up and down smoothly. We had this brand on hand, so it was a good way to avoid unnecessary purchases. We also implemented a Neo 550 motor as it was lightweight and effective for the longevity of the challenge. We used REV instead of MK4Cs because MK4C work better with regular competition chassis and we can save them for our main FRC robots. However, we found a further issue: fitting the manipulator with the elevator and making sure they didn’t interfere with each other, as the manipulator kept hitting the elevator. We plan to draft more manipulator designs on day 2.
While design team worked, programming team worked on programming radios to run data to the robot using an FRC imaging radio tool. Manufacturing team worked on field element construction. Using table saws, band saws, and angle grinders, they used PVC pipes for the coral reef, and used custom 3D printed joints to fit pipes together. They also worked on building wooden structures for the barge and coral reef base, and bird net for netting. Then a deep cage was constructed, cutting out metal pipes, plasma cutting out top and bottom plates, sandblasting plates to remove rust, and welding together the pieces.
Finally, we worked on electronics for the chassis and finished gussets and bars.
The Reef
We decided to make our own version of the reef using PVC and 3D printing. This presented some problems that we solved in iterations. We have the files open for sharing at this point as well. An issue we ran into involved the tolerance of the 3D printed jointed. It was too tight, so we decided to incorporate a slot too allow the walls to flex. This enables a looser tolerance. We also added self-tapping screws to the prints to prevent the pipe from rotating, keeping it in a stable position necessary to utilize the game piece.
35 Degree T
This custom bracket holds the PVC pipe in the correct position to create the main structure of the reef.
Spacer for holding PVC in correct position at higher spots
This is a stabilizer that holds the PVC pipe to the other part of the reef. This prevents movement and doesn’t allow the reef to wiggle around when it comes in contact with the robot.
The ball does not touch this bracket at all. Luckily, our design provides for little variation between our reef and an official competition piece. With all of the brackets The Tube Lengths are as follows:
We are still continuing on our other field elements, but we are close to getting the barge completed. In order to stick with our sustainability plan, we are re-using as many materials from previous game pieces as possible each year! No new wood was purchased for this project. In particular, we took plywood panels from last year’s stage and speaker in order to the barge.
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The PVC pipe for the Reef, is this all 1.25" sched 40 PVC pipe? Or did you use another size you had on hand?
Hey when I opened the CAD it was view only and I wasnt able to export the file to stl. Would it be possible to some how allow people to export the file? Thanks!!
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We are using 1 1/4" and we’ll look at the cad. The links should allow for export.
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Our design team started the day designing side panels for sponsors and mounting electronics, attaching a power distributor for all motors. The design for coral collection we ended with last night was scrapped. We realized that the opening we needed to capture the game piece at required too precise of movement to place. We came up with the idea to drop the coral into a tube ramp, dropping it at the same angle as it is picked up from, and this tube ramp would be attached on the outside of the lift. The algae would sit more on the top of the elevator that at a clamped base. We also changed the lift to have 4 sets of slides rather than 3 as we needed to add more height. When fully extended, the bars would reach a height of 101 inches. Design team also finished making sheets for the lift system for manufacturing.
Meanwhile, manufacturing worked on the barge. They ran into some issues with the 3D printed reef joints. Originally, the tolerance was too tight, but we resolved this issue by adding grooves so the joint could slightly expand when the PVC pipe was inserted. Programming team discovered some complications as the 2025 Regular Version was not yet available for the library they were utilizing, and so had to revert back to beta versions. They also started programming servos in hopes of clamping algae in place, though this was subject to change in case of design modifications.
About halfway through our day, design extended our original chassis to fit our battery, requiring us to cut bars and add an extra layers of bars. The lifts were also adjusted to sit in the front of the robot rather than the back, as its original placement made the hole in the center too small. Manufacturing team planned to wire motors to the power distributor, and the lift system was being constructed. They ran into issues with the barge, where the FIRST sheet set for designs was around a foot shorter when comparing measurements with its video version, so our field was too short. To solve this issue, we plan to add spare wood underneath the barge to lift it up more. We also with our bird net as it was not strong enough to hold the weight of the algae when it was thrown in. Our solution was to use polyester mesh as it is what the actual net in competitions is made of and more durable over all.
We ended our day with some major design changes, with a new manipulator that picks up both game pieces. It is sprocket driven with a higher torque, and has a compliant wheel intake. A Neo Vortex motor controls a pulley system that allows two sets of compliant wheels to spin. The two sets of compliant wheels consist of two inner wheels that are squishier and two firmer wheels on the outside to hold the algae better. For our coral, it is held by a 6 inch diameter PVC pipe. It has a passive mechanism, allowing the coral to rest at against an end stop. When lining up with the reef, we incorporated a V-Shape located at the end of an attached bar on the bottom of the holder. When pushing upwards against the reef, a rubber band on the bar will squeeze the pipe, releasing the coral into place. A REV encoder on top of the lift also lets us know the position of the system at the final axis of rotation instead pf the motors to negate slop. As the crossbars on the lift were an issue, the movement of the system is approximately 120 degrees, and heat set inserts connect the plate of the algae to the tube holder, and connects this shaft to everything else. These heat set inserts were critical for reusable threads, adding extra strength and allowing us to screw and unscrew multiple times without destroying the 3D printed part. Manufacturing finished assembling the lift with minor errors, struggling with size of the bars and running out of material, but were able to substitute different bar stock material.
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It says view only for me too. Couldn’t find the export option in the usual place.
We’ll work on that for tomorrow. Sorry about that! We have a new updated version that we will be tossing into a Google Drive Folder with 3mf & stl files.
Links are Updated AND we have a new Google Drive Folder where we will be sharing out files for Printing:
We are also dropping in our Adafruit Camera Mounts.
They are currently designed for M4 Threaded inserts (heat press). Drop any questions!
We do have more modifications coming for the reef as we work with the model and the physical prototype.
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Our manufacturing team has been hard at work today. We began the day by assembling our slides for our lift and assembling the manipulator according to our design. We also set up our field in preparation for testing our robot in later stages to ensure everything ran smoothly.
In previous posts, we had thought that the barge was an incorrect height on the FIRST sheet sets. However, we found out that it was just confusion on our end, as in the center of the barge, there was a panel that was a foot longer due to the fact that it needed to prevent the algae accidentally bouncing into the opponents side of the net. Therefore we had the correct barge size, working out in our case. We also worked on other components of our field set up, including a processor station for the algae. We also incorporated hose clamps onto our reef to keep the 3D printed joints from snapping and reinforcing them.
Once the main structure of the robot was assembled, we had several minor issues that were quickly resolved. For example, we did not have enough clearance for our elevator motors to fit as a bearing was in the way. By moving the plate the motors were attached to on the outside of the lift instead of the inside, we were able to move around the bearing issue. Another small complication we had was that the chain on our sprocket hit our pulley system. To resolve this, we adjusted the pulley by moving it closer to the center of the cross bar on the elevator. Despite our overall idea remaining relatively the same, these little fixes became very time consuming, making the challenge harder, but ultimately were issues that would’ve been hard to spot with CAD only and were needed changes to keep the process running.
While manufacturing team worked to make improvements and modifications to the robot, design team also began to CAD a climber in the case that we’d have time to include this capability. The idea was a linear actuator that would be attached to the first slide of our lift system, which would push against the inside of the cage’s base. We would also include a shape that would help guide the cage and keep it centered, allowing for easier direction to the hole so we could climb. Eventually, due to time constraints, we felt that this task was no longer feasible, but hope to possibly utilize the idea in our main FRC robot.
Finally, our programming team set up programs for our elevator, intake, and rotator using Java and YAGSL Swerve libraries. When running our elevator subsystem, we ran into a problem, as our motors pivoted. The rivets were loose, especially on the right side of our robot, causing our lift to seize up and skip. With adjustments, we were able to run it smoothly as intended.
Regardless of not being able to complete all of our goals for this challenge, including climbing and full programming, we are very proud of our team and end product!
Tonight, we spent time revision our Robot in 3 Days. We adjusted where the pivot point was on the coral collection due to changes in CAD and changes in the final bot. We were able to lower the coral collection by 2 inches on our lift. The goal was also to enable us to gather algae from the reef as well.
We were able to also refine our coral collection mechanism.
Next, we plan to add a climb to this robot.
We are still making revisions to the CAD to keep it on par with the physical changes. This was our first time doing Ri3D, we set too lofty of goals but were trying new things we’d never done before to see if we could pull them off in the season. We now have more experience with Rev Max Swerve, building our first elevator mechanism, creating star CAN networks for each swerve module, and overall improvements to wiring practices. Overall, we consider this a success as our design team dives into their CAD modeling and prototyping. Prototypes will be going live this Saturday! Stay tuned.
Theseus (Primary Robot) CAD - Current iteration and Brainstorming
Feel free to drop and questions here. Soon, we will also be dropping information about how our Marketing, Business Operations, and our Sustainability (New this year!) Subteams operate.
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Is the robot able to reach behind? It might be easier able to dealgifiy the reef from the other side
Right now, it can rotate, but doesn’t have the length or correct angle at that height due to the stabilizing/pulley bars for the elevator., we are actually tuning the geometry of the mechanism to reach further. We added 4 in compliant wheels in this example. While this is in progress and having adjustments made to it, the design team is working on another iteration of the robot.
A part of our goal of Ri3D was to come up with an iteration for Programming to work with and offer feedback on mechanisms and to continue to refine our wiring strategies. We’ll have some more updates on mechanisms later today.
Thank you for the feedback!
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For those who are looking for some solutions for Billet Treads that can be 3D printed. We’ve all struggled with swapping tread on our SDS modules. We’ve done the full 3D printed wheels, but wanted to reduce our material usage and swap faster. Here’s some options to look at:
Simple Tread - Template
V Tread
Spiked V Tread
Spiked Tread
Open Alliance 3D Printable Files
Files are located in this folder in Google Drive as .3mf & .stl
We can try to make other tread patterns, but we’ll update you on testing of these treads. Currently, we are printing some tests out of 95A Bambu HF TPU.
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