6 wheel swerves

Thanks all! Just finished watching their video on youtube from 2010. Seems nice. The only real implementation I can see is extra pushing power in all directions, which is in itself useful, depending on the robot.

[Aren_Hill]

If you want to know more about that message Dillon Carey, he's the one who made the thing

[Akash Rastogi]

Originally Posted by Aren_Hill

If you want to know more about that message Dillon Carey, he's the one who made the thing

People tend to forget that 1625 isn't solely Aren Hill.

[Lil' Lavery]

Originally Posted by SuperNerd256

Thanks all! Just finished watching their video on youtube from 2010. Seems nice. The only real implementation I can see is extra pushing power in all directions, which is in itself useful, depending on the robot.

See the litany of other threads on the issue, but more wheels does not mean more "pushing power."

[thefro526]

Originally Posted by Lil' Lavery

See the litany of other threads on the issue, but more wheels does not mean more "pushing power."

This is not always true, especially with small rough-top tread wheels. I believe someone posted Data on the subject that showed a ~20% increase in Pushing Power/Tractive Force/Force of Friction when a 4" wheel was widened from 1" to 2". (For all intents and purposes, the same as adding another 1" wide wheel to the DT.)

This seems to be caused, at least in part, by the way rough-top tread interfaces with carpet.

^ What Dustin said.

[Lil' Lavery]

Originally Posted by thefro526

This is not always true, especially with small rough-top tread wheels. I believe someone posted Data on the subject that showed a ~20% increase in Pushing Power/Tractive Force/Force of Friction when a 4" wheel was widened from 1" to 2". (For all intents and purposes, the same as adding another 1" wide wheel to the DT.)

This seems to be caused, at least in part, by the way rough-top tread interfaces with carpet.

Please provide a link.

[Aren_Hill]

234 has not posted the Data online, as it is their choice. But Chris graciously sent me the info and test setup they used to determine traction differences. They compared 4",6", and 8" wheels, 1" and 2" wide. 4x2 wheels won out by a very significant margin

[thefro526]

Originally Posted by Lil' Lavery

Please provide a link.

I don't have a direct link to the data as it was given to me second hand.

If all goes well, I will have some data soon on the relation between pushing force and contact patch once we complete testing with our prototype chassis.

[JamesCH95]

Originally Posted by thefro526

This is not always true, especially with small rough-top tread wheels. I believe someone posted Data on the subject that showed a ~20% increase in Pushing Power/Tractive Force/Force of Friction when a 4" wheel was widened from 1" to 2". (For all intents and purposes, the same as adding another 1" wide wheel to the DT.)

This seems to be caused, at least in part, by the way rough-top tread interfaces with carpet.

Originally Posted by Lil' Lavery

Please provide a link.

I think that the principal is sound from a real-world physics standpoint. I think that it is very possible to see significant traction gains from wider wheels.

From my race car experience (both designing, setting up, and driving) I have learned that polymers' coefficient of friction is related to their contact pressure. A larger contact area therefore leads to a higher coefficient of friction.

They way it was explained to me is that as a polymer, i.e. roughtop or a tire tread, is pushed onto a surface small parts of the two surfaces become interlocked. As normal force between the two surfaces increases, the two surfaces interlock less and less per unit normal force. At some point the polymer/material interfaces are completely saturated and there is not much more grip to be had.

[JesseK]

Quick aside -- if 234's data is true then wider treads also make turning more difficult due to extra skid traction (if implemented across all 6 wheels).

[Brandon Holley]

Originally Posted by JesseK

Quick aside -- if 234's data is true then wider treads also make turning more difficult due to extra skid traction (if implemented across all 6 wheels).

While I'm not certain of the exact testing setup 234 has created and tested, we setup our own system.

I can verify that 4X2 won out in our setup as well.

-Brando

[Ian Curtis]

Originally Posted by Brandon Holley

While I'm not certain of the exact testing setup 234 has created and tested, we setup our own system.

I can verify that 4X2 won out in our setup as well.

-Brando

Brandon/234/Aren,

Did you use a flat plate of tread of varying sizes or use actual wheels and some kind of load cell? Did you do both? It probably doesn't matter for the final result, I'm just curious how much of that increase is due to straight up surface area or if you get "bonus traction" due to the changing radius and interactions of the wheel/carpet interface under different loads.

[Lil' Lavery]

No offense to 234/125, but until I can see the testing set-up, parameters, and data first hand I reserve my right to be skeptical.

Additionally, I'd like to see if they evaluated a greater quantity of wheels compared to wheel diameter. While I don't doubt there would be a correlation there, I'm curious if it's a 1:1 relationship. After all, this point did originate with having 6WD swerves providing more "pushing power."

Ok. Now a new question for those who have used swerve:

Wild swerve, Revolution swerve, or custom swerve?