2015 FRC prototype two speed swerve drive first run
 

https://www.youtube.com/watch?v=T0lR...ature=youtu.be

As the title states, the very first time this bot has moved! This is only with a few hours worth of coding so it's barley functional(in fact it's just partially functional, there is still no rotation!) and highly untuned. so far things look very promising. The whole point of this test to see how fast it would go and how the shifting behaved. The reason it fell apart at the end was because an untightened screw came undone from a retention shaft so the gears kind of just flew out. As you can tell the speed is great, you can clearly tell when it's in low and high gear from the sound it makes and the speed it goes. The shifting works great too but under high stress we need more pressure so we will be upgrading the 3/4" pistons to a bigger bore. With a few weeks worth of programming and tuning it should perform beautifully. Longevity is still yet to be determined but so far we are VERY happy and excited about it. This is as rough as it can possibly be, only going to improve going forward.

Re: 2015 FRC prototype two speed swerve drive first run
 

What's you resoning behind 6" wheels over 4" ones? Smaller would also decrease the required piston, so you could keep your current ones.
Looks really good. You could go faster in high gear if you wanted I think, but it's your call.

Re: 2015 FRC prototype two speed swerve drive first run
 

we just had them laying around? lol. there really was no specific reason other than we just felt like it. though we can use any size wheels we want provided we adjust the gearing accordingly(which we can very easily with the chain). We may indeed end up using 3" wheels and making proper size blocks to lower the whole profile and maybe use two spur gears instead of the chain but that's just what we went with for now.

we can indeed go faster, or have more power. This was just a starting point. we can even adjust these factors between matches if we wanted to depending on the opposing alliance by changing the sprocket sizes! talk about versatility!

Re: 2015 FRC prototype two speed swerve drive first run
 

That's great! Yeah, go down to 3" if you can, as you are just driving on a flat right now.
Gears are more efficient than chain, but they are less versatile.

Re: 2015 FRC prototype two speed swerve drive first run
 

ah yes that reminded me of the reason! we went with big wheels for potential obstacles. It's easy enough to design down but not so much to design up. If it's a flat field then we will probably use small wheels but for now we're going big in case there is anything where it's advantageous to go with big wheels like obstacles or game pieces. If that's not needed then we can pretty easily shrink the design down accordingly

Re: 2015 FRC prototype two speed swerve drive first run
 

You're in good company. I heard Team 16 does similar "larger" modules year after year, and iterates the same design, in case a game comes which requires crossing field obstacles. I think their drive coach told me this at champs, but I can't remember for sure.

Congrats on getting a working (mostly) system built in the fall! Start working out your code issues now, there is hardly any time for that come January 3rd. Best of luck!

-Mike

Re: 2015 FRC prototype two speed swerve drive first run
 

There are a lot of swerve codes out there floating around for all types of control configurations. If you get stuck look at some of them.

Re: 2015 FRC prototype two speed swerve drive first run
 

I know you said you may change it, but for reference what speeds is it geared to in the video?

Re: 2015 FRC prototype two speed swerve drive first run
 

It's also a function of the way their modules are designed. Going to a smaller wheel doesn't significantly decrease the size of their module or the footprint it takes up because they spin the entire CIM around. Opposed to modules like this (which I'm calling 118 style) which just have to have clearance for the wheel and requisite gearing.

Source: A rather in depth debate with John about it.

Re: 2015 FRC prototype two speed swerve drive first run
 

coding is no issue really i just need sufficient time to work on it. in the videos that's just a few hours worth of code so given a reasonable amount of time i can get it working pretty good :D

Re: 2015 FRC prototype two speed swerve drive first run
 

coding is no issue really i just need sufficient time to work on it. in the videos that's just a few hours worth of code so given a reasonable amount of time i can get it working pretty good :D

Re: 2015 FRC prototype two speed swerve drive first run
 

low gear is 16 to 1 and high gear is 8 to 1. with a 6" wheel. but as stated we can fine tune or drastically change that with changing the chain sprockets. we think we like these ratios though.

Re: 2015 FRC prototype two speed swerve drive first run
 

Those poor gears. What did they do to deserve such treatment? :(

Re: 2015 FRC prototype two speed swerve drive first run
 

well the first one that flew out was a 30 tooth idler one that was supposed to have a pin in it to couple it to the shaft. I have not yet installed any of the pins =\ but it had no where to go and since we're not using the speed sensors yet from that shaft and was so anxious to get it moving around i kinda of skipped that for now.. xD the second gear which was a cluster came out due to the main failure. a number 8 screw that keeps the entire shifting block attached to the frame on a spinning, pivoting shaft. That screw had no lock washer or locktite on it so we knew that would happen sooner or later but didn't really care and just wanted to see how fast it would go!

so yea that was all our, or rather i should say my, fault. but it's ok! nothing broke so after break we can resume more testing and abuse of the system! after a lockwasher and locktite that is xD and probably that pin as well...

I kind of like that it failed and how it failed, it adds a bit of humor at the end xD

Re: 2015 FRC prototype two speed swerve drive first run
 

You may want to video using a high-frame rate camera. It looks like one of the modules points in a different direction from some of the others after what looks like a change in direction. I don't know if this is intentional or if it is related to the gears that came loose.

Re: 2015 FRC prototype two speed swerve drive first run
 

we don't need a high speed camera for that. you are indeed correct. as i stated at the start this is with just a few hours of coding and just barely enough code to make it move. it's just due to very un-tuned parameters and can be fixed up when i have a bit more time to put into it.