Vector 8177 Build Thread | Open Alliance 2023

This is fantastic work, thank you for sharing. Hopefully we can get some reports from the official week 0 event in a few weeks to see if these results transfer on to the real fields.


Did you control release height up the ramp? We found (in less extensive testing than yours), that releasing the cone flange first (90 degrees in your diagram) at a point near the end of the ramp could almost always make it roll over, so the tip points out from the wall. Releasing it about mid way up the ramp seemed to be best for upright landings, and releasing it at the highest point was less predictable. I’m curious if you get the same results.


Yes! We made sure to always drop from the same height at every trial. It’s a bit hard to see in the video but we drew a horizontal line across the top of the ramp to mark where the tip of the cone should be at every drop.


You might try repeating tests at a different height then? There’s less energy if you drop from the bottom of the ramp, so maybe the consistency improves?

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Here’s a few tries (2) of us dropping from half height:

Half Ramp Drop

Dropping from the ramp at half the height actually led to a decrease number of successful drops. Just based off of quick observations, the cone wouldn’t gain enough momentum from half height. The cone would clip the secondary polycarb ramp, causing it to lose the necessary force to right itself.


Design :clap: Review :clap:

Look! It’s a completed robot! (in CAD… mostly… it’s mostly completed…)

We talked a little about our design choices in our previous posts, but we never really went in depth with our entire robot. So with our CAD mostly finished, let’s take a deeper look at what our bot will look like this year.


Our bot for this year is themed around two core ideas: simplicity and strength. In other words, we wanted a bot that was modular enough to easily replace broken parts but also strong enough to withstand the competition season so that we don’t have to be replacing parts in between every match (cough‌ 2021 Texas Cup cough‌).


Ultimately, we decided to split our robot into three main subsystems to achieve those core principles — drivetrain, intake, and elevator + arm.



Pretty early on, we decided to go for a swerve chassis. With how the field is set up, having a drivetrain that can maximize mobility would enable us to easily slip through defense and better position ourselves to score points.

The drivetrain itself is a 26” x 26” frame with SDS MK4i swerve modules in L3 configuration. We went with the L3 configuration because we believed it provided the best balance between speed and torque that would be needed for this game. The smaller form factor of the chassis would make avoiding defense, navigating the Community Zone, and balancing on the Charge Station with our alliance partners easier.

The corner of our swerve modules features 3D printed pieces that were stolen from inspired by Spectrum. The 3D printed pieces pushed our frame perimeter out by ¼” on each side of the chassis, allowing us to mount up to ¼” plates on the outside of the tube, which will come in handy when designing the support structure for the elevator. The top of our MK4i also has 3D-printed covers that prevent objects from getting into the swerve modules while also doubling as mounting points for the spark maxes. Doing so declutters the belly pan and enables cleaner wiring.

Spectrum Corners

3D-Printed Module Covers

Speaking of belly pan, this year we’re going for a ⅛” unpocketed steel belly pan. Is it overkill? Definitely, and we’re all for it. The belly pan and the steel gussets used to attach the aluminum box tubes will significantly lower our center of gravity (COG), allowing us to worry less about our robot trying to learn how to do a flip mid-match. The rigidity and strength of the steel parts also just ensure the chassis is more robust, which is always a plus. :cowboy_hat_face::+1:

The last major design consideration we made for our drivetrain is our bumpers. We opted to go for a bumper cutout to allow for our intake to angle itself into sucking up cones from the floor (more on the intake below).




The initial idea for the intake was more of a grabber/pincher type mechanism, but as more prototyping was done by us and other teams, we latched onto the idea of the triple roller intake design. We noticed that this method would enable us to better implement the “touch it, own it” idea as cones/cubes would immediately get sucked in once in contact. Some examples of the roller design in action are the Everybot, Spectrum, Mechanical Advantage 6328 (Prototyping), etc.

The triple roller intake uses 2.25” 40A durometer-compliant wheels for the front two pinch rollers. This gives it a softer grip and makes intaking cones faster and more tolerant. We also have a pretty dense row of wheels because we noticed cones had a harder time getting pulled in when the gap was too large (even if it was partially touching a wheel, having less surface contact would worsen the grip).

Having the front bottom roller be compliant also benefits the intaking of cubes, which use the bottom two rollers (the front one being compliant, with the back row being stealth wheels). Using stealth wheels on our back roller allows for a firmer and more uniform grip on the cube, allowing us to “shoot” the cube forward and score.

We managed to get some of assembled this week and have some testing of shaking the cube and cone around without it falling out.

Cube Shake Test
Cone Shake Test

The intake is powered by a NEO motor on 2:1 reduction. In order to use only 1 motor for the robot, we created a gear reversal to swap the direction of the front bottom roller. This allows for the two front rollers to spin inwards for cones, and the two bottom rollers to spin inwards for cubes. Also, we chose to add an entirely separate gear reversal plate instead of just two big gears on the front rollers (like the everybot intake) for two reasons: we want to pick up tipped cones which require us to lower the intake very close to the ground and having big gears would impede that, and we also wanted the mechanism to be protected from harm so we kept it in the bumper perimeter.


Our intake design is also on a powered pivot which gives it a lot of freedom in terms of intaking and scoring. In order to properly constrain the intake, we decided to print custom hex hubs out of carbon fiber. They sandwich the polycarb plates on either side and prevent axle twisting.

This year, we plan on using a lot more 3D-printed parts such as pulleys, spacers, hex hubs, and electronics mounts. This allows us to have a lot more freedom when designing and also saves us a lot of money (I think we spent like $200 on pulleys last year on aluminum pulleys). Spacers and mounts will just be printed from PLA. But for more wear and tear parts like pulleys and the hex hubs, we plan on printing them from CF filament, giving them a lot more strength to hold up over the season. Our 3D printing has also been greatly improved by the addition of the Bambu Labs P1P which we 10/10 would recommend to other teams if it’s in your budget!



(It does look like a sitting dog, doesn’t it… especially if it’s extended)

From early on in the season, we knew our robot would likely have a tilted elevator. Since this is our first year EVER building an elevator of any kind, we wanted to make sure that it was robust and could withstand the trauma of the competition season. We knew we didn’t want to go fully custom, and after doing a lot of research, we landed on a “Franken-cots” elevator design that uses Thrifty Dyneema rigging + chain combs and WCP bearing blocks.

On the topic of COTS, one of the major design choices we made was gussets vs tube plugs. Because of packaging constraints and recommendations from other teams, we eventually decided on using tube plugs for the construction of our elevator. By having less tube face taken up by gussets, we could compact the elevator as much as possible. Using tube plugs also allows us to spend less time at the CNC, and more time building.

Like the drivetrain, we’re slapping solid steel mounting gussets onto our elevator and yes, they are 100% overkill. However, again, like the drivetrain, that was intentional from a design and strategy standpoint. Strategically, our COG is super low, sitting at only 8” off the ground when fully extended. We should never tip… From a design standpoint, the completely overkill gussets strengthen the robot, hopefully preventing any more 2021 Texas Cup mishaps. Can you tell how traumatizing the 2021 Texas Cup was for us? It was fun tho…


The elevator is powered by 2 NEOs, each on a 9:1 ratio. The elevator gears are used in order to keep the motors as far inside the robot as possible to prevent possible damage to them (don’t want them sticking out and having wires getting snagged by intakes/grabbers). In order to further protect the motors and gears, we designed 3D-printed gear covers in order to keep debris and game elements from getting tangled up in the mechanism. In addition to the gear covers, we also have a large polycarb back and side shield to further protect the motors and rigging from damage.

Our chain rigging has ThriftyBot chain combs, dual chain drive, and dual Dyneema rigging, making it look very similar to a thrifty elevator. This was done because we wanted a tried-and-true design concept without having to prototype one.


The wrist has dual chain power to reduce twisting and for added redundancy. The pivot is powered by a single NEO on a 24:1 ratio (12:1 max planetary + 2:1 sprocket). Since we wanted to keep our bot relatively small, the carriage also ended up being pretty narrow, which meant to package the NEO controlling the pivot, we had to tuck it in between the arm tubes. We used a REV MAX 90-degree gearbox for reliability and compatibility with the rest of our motor hardware. Bolts will go through the tube, through crush blocks, and through spacers into the gearbox to secure it. In order to keep track of the wrist position, we plan to use a through-bore encoder to keep track of our absolute position.


Our carriage gusset is ⅛” bent aluminum that wraps all the way around the carriage, exploring a design style new to us.



Bill of Materials: 2023 BOM




And finally, we got our 3D-printed field from FIRST Choice. It only cost us 100 credits and some fixing up :,)

Mini Cone Test


Vector Jig

In continuation of our earlier post on cone drops (Cone Drop Testing), we proudly present the Vector Jig!

The Vector Jig is a portable item that’s used to drop the Charged Up cone off the human player station at the perfect height and angle so that it always lands pointing away from the wall (and toward your robot with a laying-cone style intake).

The jig has a lip that extends outwards from both sides of it, allowing a human player to use the jig on the red or blue side of the field.

While we couldn’t find anything prohibiting this type of item in the game manual, we are open to any feedback from anyone who might have caught something we missed. The cad has been linked below with a slot-style mounting pattern that can be used to line up the center piece, but as it is a relatively simple item, you may want to modify it to best suit your fabrication setup if you make one yourself.

CAD link for the Vector Jig.

Also: see our mini cone drop test!

– Aakarsh



Such a good team


This is sick. While 7525 isn’t planning to intake floor cones, we’ll be making a pair of these to loan to alliance partner human players in case they are!


I’m not sure this complies with H303. Doesn’t seem like it meets any of A-G.


Thanks for pointing that out! We weren’t too sure whether it was legal or not, but we decided to make it anyways for fun/as a proof of concept. I think during competitions we’ll probably stick to dropping cones vertically (unless our human player has crazy muscle memory :joy:).

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I couldn’t tell for sure, but was your HP single station modeled after the actual field or the “home version”. If I remember correctly there was a 60 degree lip on the real field which doesn’t exist on “home version”.
for reference:


Yes, we added the secondary polycarb ramp to our setup. As long as you release the cone from high up, it gains enough velocity to clear the steeper (60°) ramp and land like normal. We have some videos in our earlier post if you wanted to check them out!


So the Vector Jig may be illegal, but we’re not done yet…

Presenting the Vector Jig V2.0: Hand Edition!

After doing some relatively simple math, we deduced that marking a line 5.4 inches from the tip of your human player’s middle finger and another line 2.5 inches beyond the first (so 7.9” from the middle finger), we can have a completely legal (we hope) and still usable Vector Jig!

We did deduce that using a marker is more reliable (and less painful) than the tape we have in the video, so that’s what’s shown in the picture above.

Also, you may notice that our top line (the 7.9” one) isn’t completely flush with the top lip of the human player station as we state that it should be, and this is only because we made a small error when constructing the human player station and it’s ½” short. This doesn’t affect the actual dropping though, so everything still checks out!

Happy Jigging!

– Aakarsh


Cool robot btw! I looked in your cad and was wondering if you guys are planning to just bend a piece of 1/16" polycarb into that shape or do you have 3 different pieces that are attached in someway. Thanks!

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The plan is currently to cut and bend a large piece of 1/16 polycarb.

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Intake Testing!

We finally received all our parts and were able to finish assembling the intake for our robot. After wiring it up to our swerve base, we did a little bit of testing and it seems to work well.

One thing we noticed was that the bottom roller didn’t need to be super close to the ground to intake cones, which gives us a little more freedom/leeway in terms of positioning. As long as the cone touched the bottom roller, it would kick up and be immediately sucked in. Even with the intake around ~1 in. off the ground, it still worked.

In the video, we aren’t at our actual scoring positions (since the power wires were too short), but it’s looking pretty good so far!

– Roland


Does this continue to work as the angle of the cone to the roller increases?

From our experience the closer we can get to the ground (to a point) the wider range of angled cones we can pickup but we haven’t tried the wheels you all are using.

Also make sure to test moving the intake into the cone and not the cone into the intake, we found that made a big difference on some of our testing.


We did test angling the cones and staying our ~1in off the ground, and it seemed to be working well. We can do more thorough testing today to determine a solid answer.

Interesting, we were moving the cone into the intake the whole time - we’ll definitely try intake to cone soon and see if our results differ.

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Absolutely agree with this. Our testing shows exactly the same thing. Cone moving to intake works significantly better the intake move to cone in when teating angles of attack. We stopped hand feeding for those types of tests now.

Thanks for posting the shooting video as well! We were playing with it the other day and know that arching shots are inconsistent but need to extend our wiring for more direct shooting as well. We are about to do the same tests! Good to know we are about on the same path!