Nonadrive Concept

[Sam Skoglund]

Hello CD Community!

I am relatively new and didn't know how to post pictures to chief Delphi, but here is a link to a Google drive folder with pictures and details about a nonadrive concept that I designed.

For those of you who may not know, a nonadrive has nine wheels. 4 of them are traction wheels and 5 are Omni in an h-drive configuration.

Any feedback would be much appreciated!

https://drive.google.com/drive/folde...jFZMDhKeTJBRjA

[ollien]

Might wanna take a page out of 148's book

Jokes aside, this looks awesome. I really like the idea of the folding bumper mount a lot.

[Cothron Theiss]

I really recommend you check out the Grasshopper Hybrid drove that 624 initially showcased.

https://www.chiefdelphi.com/media/papers/2968?

Also, just search for Grasshopper drives on here and you'll find several threads with a lot of great information. I'll comment on a few things, but a lot of those threads have information that would help you as well.

Your speeds are high. Are those the theoretical or adjusted values? If you aren't, I'd suggest you use the JVN Design calculator to determine your actual speeds when driving. Remember that your "Weight on Driven Wheels" will not always be 100%. That can make a big difference.
Also, it looks like you've got a fixed strafing wheel in the middle. With n-wheel or actuating wheel drives, you especially need to have some way to actuate your strafing wheel so you can actually get a decent amount of weight on that single wheel.
I'm not a big fan of the way you've attached your actuators to the modules. It looks like there could be a lot of flex in the system, especially if the clevis rod doesn't slide along the slot as smoothly as you expect. Were that to bind mid-shift, you could end up damaging the modules if the pneumatics have enough power.
I like the profile of your gearboxes. Compact gearboxes are a wonderful thing.

Keep working on this design! It's a great way to test out a lot of concepts needed for building great robots.

[Sam Skoglund]

Originally Posted by Cothron Theiss

I really recommend you check out the Grasshopper Hybrid drove that 624 initially showcased.

https://www.chiefdelphi.com/media/papers/2968?

Also, just search for Grasshopper drives on here and you'll find several threads with a lot of great information. I'll comment on a few things, but a lot of those threads have information that would help you as well.

Your speeds are high. Are those the theoretical or adjusted values? If you aren't, I'd suggest you use the JVN Design calculator to determine your actual speeds when driving. Remember that your "Weight on Driven Wheels" will not always be 100%. That can make a big difference.
Also, it looks like you've got a fixed strafing wheel in the middle. With n-wheel or actuating wheel drives, you especially need to have some way to actuate your strafing wheel so you can actually get a decent amount of weight on that single wheel.
I'm not a big fan of the way you've attached your actuators to the modules. It looks like there could be a lot of flex in the system, especially if the clevis rod doesn't slide along the slot as smoothly as you expect. Were that to bind mid-shift, you could end up damaging the modules if the pneumatics have enough power.
I like the profile of your gearboxes. Compact gearboxes are a wonderful thing.

Keep working on this design! It's a great way to test out a lot of concepts needed for building great robots.

Thanks for the reply! The speeds are theoretical, but not from the calculator. I will take a look at the calculator. Also it is hard to see in the pictures but the entire cim/gearbox/wheel strafing assembly pivots, and would be pressed against the ground with springs or rubber bands.

[Ginger Power]

I think it's a great start! 80 lbs seems pretty heavy for just a drivetrain plus electronics. There definitely looks to be a lot of weight that could be cut. Is this something that your team is looking to build, or just a thought experiment?

[Sam Skoglund]

Originally Posted by Ginger Power

I think it's a great start! 80 lbs seems pretty heavy for just a drivetrain plus electronics. There definitely looks to be a lot of weight that could be cut. Is this something that your team is looking to build, or just a thought experiment?

Our team lacks a lot of manpower and doesn't have a lot of access to good machining tools, so it was just more of a design idea. That being said, if the game this season fits this style of drivetrain well, we might revise it and attempt to build one.

I think the weight could be cut down quite a bit from some sort of lightning hole pattern, I just wasn't motivated to CAD model such a thing!

[Ginger Power]

Originally Posted by Sam Skoglund

Our team lacks a lot of manpower and doesn't have a lot of access to good machining tools, so it was just more of a design idea. That being said, if the game this season fits this style of drivetrain well, we might revise it and attempt to build one.

I think the weight could be cut down quite a bit from some sort of lightning hole pattern, I just wasn't motivated to CAD model such a thing!

I've put a lot of time into nonadrives/decadrives or as I like to call them, butterslide drives. I will be presenting about FRC drivetrains at Jumpstart at St. Cloud State University. It'd be awesome if your team could make it there!

I think it would be really cool if you modified this design to be built with your team's resources. Adding constraints like that make these designs much more challenging and in my opinion fun.

[CalTran]

Any reason for Nonadrive over Octacanum?

[Sam Skoglund]

Originally Posted by CalTran

Any reason for Nonadrive over Octacanum?

I chose the omni wheels over the mecanum because it would allow for faster and smoother speed in all directions. I designed this in the summer as sort of a "best possible" all around drivetrain. If we decided to build something like this, I would reconsider the Octanum option because it is easier to manufacture.

[echin]

Some thoughts:

I'll echo the above comment about actuating the center wheel to get more down force. My FTC team is currently using an H-drive and having a center wheel with variable down force has proven to be very important for smooth driving.

Also, it might be a good idea to reinforce the drop down wheel modules a little more. They look like they might bend easily from a side hit with the traction wheels down.

Overall, this looks really good. I'm curious to see how it develops!

[dradel]

interesting setup. would love to see a similar concept based on a kop chassis

[DaveL]

Nice Job.
As others have posted, you might run into problems with your pneumatic cylinder. I would mount the cylinder with a bolt as a pivot to the back (bottom) of the cylinder. That way it can align to the wheel strut's movement path.

Can anyone talk about how a bot like this turns? For example, are the turns sharp and crisp or wide and slushie?

Dave

[roboruler]

Originally Posted by dradel

interesting setup. would love to see a similar concept based on a kop chassis

The KOP chassis is designed to be a simple and reliable system for teams. Trying to do this with the KOP chassis would be far more work then it is worth, just use tube/Versaframe.

[dradel]

going to have to disagree... there are many teams that use the kop chassis, and have done different drive types using the chassis.

plus the inspiring of teams to think outside of the box is priceless! let alone the experience gained in cad by doing such a project

[Knufire]

Originally Posted by roboruler

The KOP chassis is designed to be a simple and reliable system for teams. Trying to do this with the KOP chassis would be far more work then it is worth, just use tube/Versaframe.

The AM14U3 is significantly more versatile that one might assume. A slide drive shouldn't be too difficult with a couple TB Nanos and some extra inside rails.