Our team isn’t able to afford swerve drive for this season so we are planning on instead building a tank drive bot again. We are all relatively new to first (our team was all brand new starting last year). I want to build a smoother and more reliable tank drive than what we had last year. Our team is planning on building a smaller bot and started looking at building a west coast drive train. Would building west coast drive be worth the time? Are omni wheels going to help smooth turning? If we use omni wheels, would we want to use 6wd with one or two sets of high traction?
Did your team get the KOP drivebase or did you opt out?
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Assuming you got the KOP drive it probably isn’t worth the development time to figure out west coast drive. If swerve is unlikely to be in the picture for several years west coast could be a good offseason project because there are benefits, but right now you’re probably better off working on your scoring mechanisms.
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You should probably build the AM14U. Making a WCD doesn’t really make things more smooth, just a nice form factor. If you haven’t made one in the off season, there isn’t a great reason to for season.
Now… If you want to upgrade your AM14U, that makes a ton of sense. I personally prefer the 8 wheel configuration, for some additional stability and more consistent turning.
I poked at a couple of your matches (match 2 and 43 of Utah specifically), and to me it looks like the drivetrain was working fine, short of a turning issue that you mention at the beginning of match 43. IIRC this is an issue regarding the amount of drop that you have on the wheels, could you share more info about your 2023 chassis? Were all 6 wheels flat or were your center wheels lowered by any height?
The big things I noticed outside of that were a high COG affecting movement, a disconnect issue (triple check your wires), and just a general hesitation when moving the robot around. Focusing on these (mainly, drive practice will help you identify the later two before getting on the field) will also help greatly in finding more success this year.
We did get it
Ok I’ll check with wiring and mess with our old drive train some before the kit gets here. I can’t remember when we switched, but I became the driver part way through the competition. Even after, we had to go slowly because the wheels would catch and bring it off the ground pretty easily. I had a trigger that halved or quarter the speed so I could turn without tipping over. Otherwise every time the wheels would skip it would take us off the ground and make it really tippy. We built the drive train that comes with the kit which has a pretty big drop in it I believe.
Custom west cost drives can be a significant upgrade of the KOP drivebase, but it’ll cost a fair bit of money and be a lot of work. If you don’t have the money/time/experience/whatever to work on swerve, you probably don’t want to focus on a custom tank either. The easiest low hanging fruit will be lowering your center of gravity, choosing the right wheels for your drivebase, figuring out easy intuitive controls, and driver practice.
- Lowering COG: pretty self explanatory, keep the weight low and you won’t tip.
- Choosing wheels: you’ll want grippy wheels everywhere you can for torque, but that can interfere with turning. To improve turning, increase the center drop, or put omnis or low friction wheels on the corners. The best configuration will depend on your application and may require trial and error. If your bot is rocking back and forward on it center wheels you probably have too much center drop and increasing it will not help.
- Driver controls: this is a software thing and I don’t know enough to be terribly helpful but, there are a lot of options to turn driver inputs into robot motion. You could have two sticks controlling the speed of each side of the bot independently, you could have a speed control and turning control, probably others. You can also map the controls in different ways, you can have 0-50% of driver control map to 0-10% of drivebase power and 50-100% of driver control map to 10-100% of power. That would give fine control for low speed maneuvering. Whatever you choose needs to make driving easy, there are infinite possibilities and other people would know more.
- Drive practice: Get as much time driving before comp as possible. This means picking a driver, training them and trusting them. Changing drivers mid-competition is usually a very bad idea. Competitions are the time to drive your best, not the time get used to the controls.
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Partrick already gave a great set of things to check/do, including for this issue specifically (as you said in the OP swapping to omnis can help, just be aware it makes it easier to push you around). In terms of driver controls, id start exploring scaling how much power you actually give the motors relative to your joystick/controller push. This should be something simple you can test with your 2023 robot, assuming you have it together still.
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