Swerve Module Damage Coming Off of HAB 2

Early in the build season 103 took one of our swerve chassis (Swerve & Steer) and just sent it off of HAB 2 onto HAB 1 to see if it was a viable strategy for the season and whether we thought the modules could handle the impacts match after match. While all 4 modules survived it was incredibly violent and we opted to never start on HAB 2 during the competition season. There were disagreements on this conclusion with alternatives such as only send it in particularly difficult or critical match-ups, but a consensus was reached that the safety of our drive-train was more important so sending was never an option.

The Numbers:
Of the 56 matches Cybersonics played in this year, there were six in which the difference was less than or equal to three points and if the outcome were to change it would be in our favor. Three of those six matches had the possibility of another team on our alliance starting on HAB 2, and those extra three points could have given us better match outcomes. This is just over 5% of our matches, one which would have tied a match in the finals, and two that would have gone from losses to wins.

The Question
To those teams with swerve modules, namely the Swerve and Steer modules (but others are welcome), did you send it? If so, was there damage to the modules? Did that damage occur over time? Did that damage cost you any matches? If you could go back and do it all again, would you send it, or no?

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We (2767) were also concerned about swerve damage especially since they are mostly printed. After several test launches with slowmo cameras filming the event, we concluded to not worry about any damage.

Never experienced any damage either to the swerve or any other parts even though the camera showed that a bunch of other superstructure parts were moving A LOT. It was like watching someone get hit in the face with a ball.

On a separate note, we never tried to go from HAB 1 to HAB 2 “Dukes of Hazard” style. We figured that would certainly shear off the swerves!

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I know this isn’t exactly what you are looking for, but there were a couple times in 2018 our robot fell after climbing and we landed straight down onto our wheels. We saw no damage of any kind from these falls (both were likely above 24" easily).

Now obviously this isn’t comparative to repeatedly driving off HAB2 but the load case is similar, or likely worse in the 2018 scenario. I think whether the modules can handle it would really come down to the steering bearing used in the module and how the wheel shaft is mounted to the module.

Like Mark noted, if we had done swerve I would have been much more nervous about yeeting onto HAB2 at the end and shearing the modules. In this case having the distance between the steering bearing and wheel shaft as short as possible would mitigate this risk as much as possible.

I think with our current module design I would be comfortable driving off HAB2. I would probably be comfortable yeeting onto HAB2 as well, though I don’t think it would work reliably, and I’m generally not a fan of the yeet method to begin with.

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We did not use Swerve and Steer, but using the Swerve Drive Specialties Mk1, we sent it off level 2 almost every match at each of our four competitions. Our robot was about half a pound under max weight but we didn’t experience any damage. I’m not sure we would have had the same amount of confidence using the Swerve and Steer modules, but the Mk1s were plenty robust.

We (2910) were using our MK2 modules. We competed at 5 events this season. For the last 3 events we sent it off of level 2 in almost every match (about 50 official matches plus additional practice matches). There was not any noticeable damage to the modules or bearings. We will continue to send it off of level 2 at off-season events.

You can see us dropping from level 2 here. Robot starting in the top left.

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We don’t have the swerve and steer modules.

We had no damage to our swerve modules from driving off Hab 2. We drove our 2018 bot (with well over 100 matches under its belt) off of Hab 2 many times on our practice field early in the build season with no issues.

By comparison, I would say that driving off of Hab 2 was not nearly as violent as some of the “jumps” that we landed during 2016 going over the defenses. In terms of severity and repetition, I would say that 2016 was more taxing than 2019, but our COTS swerve that year survived just fine as well.

We also had been concerned as this year as we had a 3D printed component in our pivots (custom modules), but we experienced no damage after about half the time going off L2, after 6 competitions (incl. 2 offseason).

In prior years we had experience several falls from climbs (2017 & 2018) with no real issue, we did see some bending in 2017 of our 1/8 inch mount plates but they did not effect the performance of the modules. Way back in 2014 using Rev modules mounted on 1/8 in plate we were turned on our head and rammed underneath directly on two modules, the mounting plates actually ripped (think can opener) but they continued to work through the rest of the event without any noticable issue.

Do you drop off sideways because length wise could get caught on the ledge or are there other reasons.

We came off of the hab long ways at the Glacier Peak district. If we went fast enough, we wouldn’t get beached. We started dropping off the hab sideways so we didn’t need to rotate to place the first hatch panel on the side of the cargo ship.

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Thanks to everyone from your responses. Though we didn’t get any direct info from teams who were using the swerve and steer modules we might do some testing in the off-season.

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