FRC T-bone-ing and Hexagonal drive

[Ty Tremblay]

Originally Posted by EricH

Ty, would you consider PVC, speed drive, or filecards to be more important for the Beatty BEAST of '02? And I'm sure Element '06 and Element '07 would disagree--winning a regional from the last pick with nothing but a drivetrain (and good partners/defense ability) kind of puts a hole there...


That being said, a drivetrain by itself won't win an event, but a bad drivetrain will lose you that event. The three most important elements of a robot are drivetrain, drivetrain, and drivetrain (Mr. Bill Beatty, in paraphrase). However, I would consider rapid acquisition of game objects to be a close fourth--and if you can acquire them, you can presumably remove them from your robot.

tl;dr: A good robot--which is a combination of a good drivetrain, a good manipulator system ("on top of" the drivetrain), a good drive team, and a good strategy--is essential to winning an event, but different teams' mixtures of those four elements can all win.

Game breaking strategies like 2002 are not an accurate example in this era of FRC. 3rd robots aren't going to get picked for their hexagonal drivetrains. They're going to get picked for having solid, well driven drivetrains. If a team has to sacrifice either of those two in the least then they are not a team that should build a hexagonal drivetrain. My team, 319, is one of those teams.

[Lil' Lavery]

Sure, there are exceptions, but I don't think Ty's assertion is incorrect. You're generally not going to win an event because you have a stellar drive train alone. A bad drivetrain can certainly lose you an event, but a good one isn't going to win without a functioning manipulator, drive team, and strategy.

Bumper profiles and bumper fabrics are things that are important for the 90th percentile teams trying to become the 95th or 99th percentile teams. They are far less important for the 50th percentile team. Rather than spending time, money, and manpower into researching bumper shape/material, it's probably better to invest that into, say, intake shape/material.

[jkelleyrtp]

I don't understand what all the fuss is about when it comes to their complexity. Instead of going all-out like 971 in 2014, many teams can easily make something like the kleinbots' offseason CAD or 148's x009 prototype.. Both of these accomplish the same goal as a hex-chassis but with much less complexity and required knowledge.

[cadandcookies]

Originally Posted by jkelleyrtp

I don't understand what all the fuss is about when it comes to their complexity. Instead of going all-out like 971 in 2014, many teams can easily make something like the kleinbots' offseason CAD or 148's x009 prototype.. Both of these accomplish the same goal as a hex-chassis but with much less complexity and required knowledge.

Not sure I'd qualify x009 as something "easy" for many or most teams to make. Good sheet metal fabrication is hard to find in a good deal of places around the country, and the design knowledge necessary is a whole other animal.

Bottom line is hex adds complexity. In some cases it might not add much, but if you're going to get tripped up on that you should probably be doing KOP or a transition drivetrain like VersaChassis anyways.

[jman4747]

Originally Posted by cadandcookies

Not sure I'd qualify x009 as something "easy" for many or most teams to make. Good sheet metal fabrication is hard to find in a good deal of places around the country, and the design knowledge necessary is a whole other animal.

Bottom line is hex adds complexity. In some cases it might not add much, but if you're going to get tripped up on that you should probably be doing KOP or a transition drivetrain like VersaChassis anyways.

You're not wrong but I don't think it would be too hard to adapt a standard WCD or kit bot chassis to give the sides a slight hex shape but exactly how hard depends on, as you said, the machining resources of the team and how much the side sticks out. The other main problem is it makes bumpers that much more complicated...

[GeeTwo]

If you're already doing a custom built chain-in-tube WCD (or any other 6WD+ design with all live axles), is it really that much harder to do a hexagon? It looks to me like it's just moving the corner wheels to the inside of the tube/channel and adding some blocks to mount the angled bumpers. Making the bumpers with the odd angles shouldn't be that much more difficult than a rectangle; the hardest part would be cutting and sewing the cloth to give a tight fit.

This is probably not a 50th percentile team issue, but I suspect it's a good bit below 90th.

[Ari423]

I have to agree that a good drivetrain won't win you an event, but a bad drivetrain will make you lose.

In 2014, our drivetrain was a sheet metal beauty. A marvel of engineering, to quote our chassis mentor. It only weighed 25 lbs IIRC, and it was sturdy to a fault. However, we spent nowhere near enough time making a manipulator, and we ended up with a robot that couldn't control the ball. At competition, we played lights-out defense, to the point where our opponents scores were consistently 40 puts below their average. We even started keeping a tally of how many robots we disabled throughout the season (we got to 9 in 2 events IIRC). But since we couldn't do anything with the ball, we never got picked for elims and we didn't make it to DCMP.

In 2015, we only spent a few days making a quick VersaFrame and Nanotube gearbox mecanum drive chassis, and we spent a lot more time working on our manipulator. By competition, we had a 100% success rate for stacking (we didn't drop a single stack), which got us picked for elims at all of our events and advanced us to DCMP (almost CMP). However, our drivetrain didn't drive straight or fast, so we wasted a lot of time lining up with the scoring platform. Also, the unnecessary weight in the drivetrain kept us from adding the air storage tanks we needed to speed up our pneumatic elevator. If we spent a little more time on the drivetrain, we might have made it to CMP.

Tl;dr - As a medium-to-low resource team, we did pretty well when we spent more time on the manipulator, but we could have done even better if we improved our drivetrain.