MK4i Hot Swap

I was wondering have any teams had the need to hotswap a MK4i module because of a failure during a event? Are there any critical failure points that create the need for a repair that would take a long time? I’m wondering because our team should decide if we want a 5th module as a replacement.

Thanks

My general tip is - always buy more than you need. Even if other teams haven’t had an issue, fixing a module during a competition is time-consuming and even may not be possible.

Switching out a module for another one, however, is a much faster process, if you have the funding it would be the safest thing for you to purchase a fifth.

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It can be easier to swap a module rather than try to fix it, but you have to take account of the fact that there is going to be a whole robot built on top of the modules and you may not be able to get access to it. You can design around this and ensure that you have the ability to swap them quickly, but it isn’t likely to be something that will happen between matches.

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Critical! I said it recently in another thread and I’ll repeat you have to have backups of motors, modules, and repair parts. My team broke 2 MK4 last season - one crash with a robot and one dropped from a hang. The modules were swapped quickly and repaired at home.

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I can tell you after over 160 matches of use the MK4is were easily the most durable element of our robot, at no point was there anything so intensive as to require a full module swap. That said your main point of wear will be the wheels. Tread requires regular (Generally one set per event when using black tread) replacement and improper handeling during this replacement time can damage the wheels (specifically by cross threading the holes for the tread screws). This can require a wheel swap which is a relatively simple procedure. I have also seen one post showing a belt failure which would require removing the upper plate, however I have not seen nor heard of this occuring elsewhere, and in the event it does occur, based on my experience with the Mark 4 (where belt failures were more common prior to switching the the wider belt) this operation would not require a full module hotswap either.

All of this in mind, 2910 does keep spare modules assembled in our pits so that if anything at all does go wrong we have well ordered sets of spare parts that we can easily draw from. I would advise a full spare simply on the philosphy that it’s better to have something and not need it than it is to need something and not have it.

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Alright thanks all

Bad things happen. They happen at the least inopportune time. You’re in eliminations and you have a module failure. Can the module wiring be disconnected, module dropped out, backup inserted, wires connected and can ID’s set if needed in less than 5 minutes? If not you may want to re-think how your swerve modules are integrated into the bot. Oh and while the module swap is going on the pit team should be able to do a systems check at the same time.

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In my mind, the MK4is being made of 7075 aluminum is a huge plus and makes them worth the extra money. We fell a few times and couldn’t break them.

That said, we did have a spare, and plan to have a spare next year if we run them again.

Yes, we had two extras and yes we ended up using both of them at some point. If your team can afford it, it is so much easier to quickly replace a fully assembled module with motors than it is to go beg teams for parts. If you don’t have any replacements and your bot falls or something else horrible happens…you have no way to quickly fix anything.

I always recommend ordering an extra, but we didn’t in this case. I am thinking of trying to have a heavy duty ball caster assembly (or similar) to swap in if there is an absolute failure. I recall at least one team saying they prepared something like that.

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As Harriam said they are very durable and do not break easily. We 2930 have not had to swap a module at all this season however we did have to swap 2 falcons and a cancoder all of which were issues not related to the module. The only issues with the modules themselves were 1 bearing was starting to go bad near the robots end of competition life span (2nd of 3 off season events) although we proceeded to play the next 2 comps without changing the bearing and had no noticeable difference with the way it drove. We also had the issue of a bolt snapping in the wheel which as stated is from the bolt getting cross threaded but with a quick wheel swap we proceeded to compete. And again as Harriam said we also keep a spare set of modules with us on that off chance we do end up needing it.

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We keep a spare set of wheels (with bevel gears), so that we can swap the wheels out and then swap the tread in the background (and not on the robot).

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