This off season, team 4004 has been working on a custom swerve drive.
We also made a Lego version to help us. There is a very short google slide link above.
This off season, team 4004 has been working on a custom swerve drive.
Looks pretty nice, especially packaging wise. A question I have about this is how the cantilevering on that CIM shaft and central shaft on the module works. It seems like this is excessively cantilevered and could be pushed down the shaft to reduce the lever arm. Is there any reason I’m not seeing for this, and has it produced any negative effects in testing?
Also, doesn’t look like there’s a lot of gearing from the CIM output onto the wheel, just looks like two fairly small reductions (belt, then bevel gear). Is there something I’m missing here?
Side note, I absolutely love those bent aluminum brackets for your motor mounting. They look fantastic.
I’ll second this, mount that sprocket closer to the motor and you’ll be better off.
Any tests on this yet? I remember seeing a design that used a similar wheel arrangement a while back and I recall there were some concerns about how well the modules would turn given that you’ll be inducing a lot of scrub between the two wheels unless you’re actively moving.
Looks good Nick.
The bent brackets are cool. You guys must have a nice brake. I mentioned to Mike that my only concern is since that saddles (bracket that holds the axle/wheels assy) are made this way, I worry the alloy (probably 3003 vs. 6061) you had to use isn’t tough enough. A side impact test which will push the wheels hard into the axle bearing would assure you that everything is ok. If good, then that is a great way to make the saddles.
Hope it drives as well as it looks.
Thanks! we have not done any testing yet, we are going to try to finish programming it today and see how the saddle holds up to heavy impact. I am very curious to see if the game this year will allow us to use the swerve drive.
Thank you! The reason that the smaller drive pulley is on the top of the cim motor shaft is because we have a set screw to hold it in place and we did not want to grind anything too close to the motor. The reason the large drive pulley so far up the driveshaft is just to keep it level with the smaller pulley. We did not lower the cim motor because of ground clearance and we originally had an 18 tooth pulley instead of a 30 tooth pulley, so the belt would not have cleared the gearbox, we just decided for now to keep it how it is and not get new brackets made for us before we even find out what the game is.
we have not tested anything yet as we are not finished programming it, I will let you know when we test it though.
There is a 30 tooth pulley on the cim shaft that goes to a 50 tooth pulley on the driveshaft, then a 2:1 gear ratio on the bevel gears. This makes the total reduction 30:100 or roughly 3 times reduction. Our calculated speed is about 14 feet/second, if it is too fast or too slow we can easily change it by making the 3:5 gear ratio closer to 1:1. Thanks for the feedback on the brackets I modeled them myself!
We have not tested this yet as we have not finished coding it yet. We talked with Stryke force at our state competition about this and they said that it does not affect the turning of the pods. There is also a 100:1 gear ratio on the am9015 motor through the gearbox giving it plenty of torque.