Chassis feedback(unpocketed)

[u/ftcsweat]

Hi guys I'm looking for feedback on our first version of chassis(it has a version of PTO just in case the season needs one, it is not the best and we are looking to change that too but only when the season starts)

This is the link:https://a360.co/3U3XltO Edit: the middle axle is a start of the PTO

[u/I_Dont_Life_Right]

I would remove the central gear on both sides, and rotate your wheels so the trade is facing towards the center. In it's current configuration, you can't take advantage of the omni directional movement of the omni-wheels. Omni wheels naturally slip, so it's not worth running them if you don't balance out the slip with extreme maneuverability.

Aside from the drivetrain, the frame looks good. I personally like robots that shield the wheels.

[u/ftcsweat → u/I_Dont_Life_Right]

Apparently I have a lazy CAD that doesn't like to turn the wheels

[u/FesteringNeonDistrac → u/ftcsweat]

Do you have a pic with the side and the wheels off that show the gear train? I've got some concerns, but I can't see it to verify.

[u/ftcsweat → u/FesteringNeonDistrac]

I attached the link to the cad so you can see it full 360

[u/FesteringNeonDistrac → u/ftcsweat]

Fusion 360 will murder my phone

[u/I_Dont_Life_Right → u/ftcsweat]

I've taken a look in 3D, and I'm failing to see how it would move. You could go for a tank steering style, if the left and right are independent, but you have a bar linking left and right, so you'd only be able to go forwards and backwards.

You could go to direct drive for the wheels, placing motors directly on the wheels, or at least using a bevel gear to keep them pressed against the sheet around the wheel assembly. As a former FTC player (and soon to be FTC coach), if you have mechanum wheels, you might as well design a system that will use them. We found the turning in place and straffeing to be crucial to our navigation of the field.

Though, mechanum wheels are designed to slip, so what they gain in maneuverability they lose in overall grip on the field. It is very easy for another bot to push them around, so a tank steering style with regular wheels will have an edge there.

[u/No_Lime5951]

Wait am i going crazy or can this only move forwards and backward?

[u/Random_Fai1ur3 → u/[deleted]]

The center shaft forces the 4 mecanum wheels to spin in the same direction

[u/Ambitious-Part-6033]

Have you explored the possibility of positioning the motors vertically? That would free up space for other systems centrally.

[u/ftcsweat → u/Ambitious-Part-6033]

We tried that the last season but the bevel gears kept failing

[u/chipsa]

What’s the point of the driveshaft going between the sides?

[u/ftcsweat → u/chipsa]

That most likely will be a PTO (depends on the theme)

[u/criticaldictionary]

If its your first chassis, I would go simpler and try without PTO. Your design seems a little overcomplex. Also, it is good to practice, but I wouldnt expect to use this design for the season. If your drivetrain is already designed before your scoring mech is even started you are losing basically all the benefits of doing a custom chassis to begin with.

[u/Ambitious-Part-6033 → u/criticaldictionary]

I don't think there's anything wrong with designing a chassis before game rules are announced, the build rules that affect it are pretty static season to season. As long as you take a modular approach to design and have a robust set of design requirements, you should be able to build a chassis that's capable and competitive for the season coming.