MK4 & Falcon 500 Failures - Don't Sit Dead Like Us

[BrendanB]

Clickbait title? Yes. But after competing this weekend we had a few issues with our motors & setup we want to share with teams so you can avoid some of our pains and keep teams moving on the field.

VEX/SDS take a deep breath you’re fine.

If you are running swerve with exposed motors in the corners (MK4, MK3, etc.), please consider making some corner guards to protect your motors if you have the weight. This game is extremely rough & fast paced! We noticed several scuffs and marks show up on our motors. One was not so lucky and took a hard hit taking out the face plate of our Falcon.

Even if you are not using swerve - guard your key components near your frame perimeter

If you are running swerve, make sure you use some Loctite in your assemblies and check your modules after every match for any screws backing out. In finals match 2 at GSD we drove with 3 of 4 modules in our drivebase. During F1 we took the bot off the field and found one drive Falcon falling off the module. We first thought it was repeat of the above failure with something inside our frame perimeter and couldn’t repair it in the four minutes we had. Upon closer inspection, it wasn’t a hit that caused this. Simply the screw didn’t have any threadlocker on it and came loose in eliminations.

We thought we had a robust plan in place to mitigate this. 3467 tore down all eight of our modules this season before events to re-assemble properly frequent checks at events. However, it looks like one screw missed our Loctite test and the tight turnaround got to us. The real failure here was in our rush to get this repaired we stripped the face plate on the motor trying to rush a repair which is completely on us.

In total we broke three motors this weekend. Haven’t diagnosed why one of our Falcons decided to stop doing the CANbus and would disconnect with tapped.

[Michael_Corsetto]

Do you mind sharing a picture of the setup on your MK4 modules? Are you running the MK4 or MK4i? The 4i’s are fairly well protected in the bottom of the robot.

Thanks for sharing all of these experiences. As another Falcon/SDS team, we are taking notes!

-Mike

[Mr.R_2]

While a bit off-topic, we had similar issues (self-inflicted) at GSD with our kitbot drivetrain.

We had the (not so) brilliant idea to mount our battery on aluminum rails pretty high up in the chassis. We spent mist of the first day of qualifiers trying to secure it.

One match, it slid out of the cradle and hit a drive motor. The case broke off and shaft bent.

We swapped it out, but had to do the full locktite service at the event. It is totally fixed now (as is our battery problem), but things were dicey for a spell.

So, lesson learned, keep your batteries low.

[Alex_Y]

Low batteries also lowers cg which makes it much harder to tip

[Mr.R_2]

Our bot was almost impossible to tip as it was pretty much just a drivetrain with a climber, but yeah. Definitely.

[Alex_Y]

You can still tip on the cable protector even with low cg. Slightly higher cg would make it more of a problem

[Mr.R_2]

True, but it was not really an issue for our bot. Of course, it is moot now as we fixed it by lowering the battery and using the KOP brackets correctly.

We do not have any mechanical mentors, so we made a few rookie mistakes this year. This was definitely one of them.

We are learning a lot though.