Team 842's drivetrain for FIRST Stronghold!

[T3_1565]

how much do the wheels move up and down from your pivot? It seems like +/- 4 inches of movement? Maybe they move freely and have no hard top or bottom in their range?

I love it. Its good to see an "out-of-the-box" solution!

[s_forbes]

Originally Posted by Bruceb

watch your bumper zone.
When one wheel goes up the other goes down increasing the height to your bumper.

Originally Posted by T3_1565

how much do the wheels move up and down from your pivot? It seems like +/- 4 inches of movement? Maybe they move freely and have no hard top or bottom in their range?

I love it. Its good to see an "out-of-the-box" solution!

There are hard stops for the travel on all of the wheels, and travel can be limited without much trouble. I believe the largest amount of travel for a wheel on the rocker is just under 2". The nature of the rocking mechanism gives the wheels a lot of travel relative to each other without moving the frame very much. (If we lift the front wheel 3" off the ground, the frame only raises about 1.5")

We're intending to show the inspectors that the robot will sit on flat ground with any orientation of the suspension and keep the bumpers within the bumper zones. This should satisfy R22 without question, but we'll also bring our team's best lawyer just in case.

[falconmaster]

Originally Posted by Ryan Dognaux

Love the yellow wheels. Oh and the drive too.

Had to do it, school colors....

[T3_1565]

Originally Posted by s_forbes

There are hard stops for the travel on all of the wheels, and travel can be limited without much trouble. I believe the largest amount of travel for a wheel on the rocker is just under 2". The nature of the rocking mechanism gives the wheels a lot of travel relative to each other without moving the frame very much. (If we lift the front wheel 3" off the ground, the frame only raises about 1.5")

We're intending to show the inspectors that the robot will sit on flat ground with any orientation of the suspension and keep the bumpers within the bumper zones. This should satisfy R22 without question, but we'll also bring our team's best lawyer just in case.

Thanks for sharing! We have similar ideas going on! (the final product will be very different, but the ideas are similar lol) Hopefully we will have something to show soon too!

[SenorZ]

Ok, yeah, that was good.

[Joseph Smith]

Very cool!
How well does it turn on carpet? Do you have a way to actuate the rocker to simulate a center wheel drop?

[s_forbes]

Originally Posted by Joseph Smith

Very cool!
How well does it turn on carpet? Do you have a way to actuate the rocker to simulate a center wheel drop?

We are planning to lock it into a 6wd dropped center configuration with pneumatics, though this hasn't been implemented yet. One benefit of this is that we will be able to adjust how much drop we have on the center wheel to make high gear more manageable to drive.

The suspension design is heavily influenced by team 39's robot from 2010. They locked the suspension into a mecanum setup that year for navigating flat ground. You might even catch a glimpse of that robot in the background of the video at the start of this thread, if you look closely...

[Rangel]

Video showcasing more what the drivetrain can do:

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

[falconmaster]

We are going to put in some faster gears!

[Nuttyman54]

Part of me wants to say that's way over-complicated, but it's so smooth and controlled I can't help but love it. There is a definite advantage to reducing the shock load on your electronics.

[page2067]

Beautiful articulation,

but the real stars are the MBS Yellow tires -

Any team that has them will shine!

[Donut]

Great music selection.

This is going to be fun to see in Flagstaff.

[Maxwell777]

Originally Posted by Nuttyman54

Part of me wants to say that's way over-complicated, but it's so smooth and controlled I can't help but love it. There is a definite advantage to reducing the shock load on your electronics.

Reducing shock to the electronics is a major benefit, but the main reason we went down this path was because of the improved control the driver has going over this terrain. With the straight pneumatic wheels on a KOP chassis, we could have easily came out of the defenses off by +- 45 degrees in either direction, in addition to the massive pitching up and down that occurs on some of them, such as the rock wall. Hopefully the rocking mount for the front wheels will help keep all the wheels on the ground as we breach.

[mrnoble]

A few questions:

-Each wheel is powered by its own motor and gearbox, correct? It's hard to see the underside but that is my assumption.

-this will be our first year ever traveling to Flagstaff. Is this the level we should expect to see, in terms of design and game savvy, from all the teams there? If so, I am a little bit excited, and a little bit scared. I've heard you guys are vicious as a region.

[s_forbes]

Originally Posted by mrnoble

A few questions:

-Each wheel is powered by its own motor and gearbox, correct? It's hard to see the underside but that is my assumption.

-this will be our first year ever traveling to Flagstaff. Is this the level we should expect to see, in terms of design and game savvy, from all the teams there? If so, I am a little bit excited, and a little bit scared. I've heard you guys are vicious as a region.

Here is a peek at the underside of the robot. All three wheels on each side are powered by a 3 CIM Vexpro ball shifting transmission. We are only using two CIMs on each side though. The 3 CIM design has better mounting points than the 2 CIM ball shifter. (In this pic, you'll note that one of our red idler rollers had shattered. It was a low fill 3d printed prototype that we probably shouldn't have used...)

Flagstaff should be a fun event this year! It's the first year a competition will be held at the Walkup Skydome. Some strong local teams, and a few from out of state. 125, 192, and 2122 are all coming to play, and they will probably make our robot look like something built in a garage by amateurs.