Robostangs 548 2016 Offseason Swerve - V01 Sidestep

[Bennett548]

The steering motor gearboxes are 50:1. They do spin very fast, so it would make sense to gear them a little lower to save some battery energy. We have not noticed the motors getting hot, so that is good.

The real test would be trying to steer while being pushed. I know that would take much more torque. We are using needle thrust bearings in the module pivot, so that should help somewhat.

Your model leaves out the friction force in the pivot bushing or bearing. You should also consider the extra toque that would be needed if the robot is getting pushed:

pushing force*height from pivot to ground*pivot bearing radius*pivot bearing coefficient of friction/pivot bearing radius/2= turning torque

N*m*m/m= N*m (unit sanity check)

The divide by 2 is assuming that you have 4 modules, but only 2 take the load because 2 are somewhat lifted by the pushing robot.

1640 did use a window motor for steering, but they only did it for their first generation pivot drive. If you do use them make sure to remove the backdrive locking pins. There is info about that on their webpage, but I can't find it just now.

[Drewit]

Originally Posted by Bennett548

1640 did use a window motor for steering, but they only did it for their first generation pivot drive. If you do use them make sure to remove the backdrive locking pins. There is info about that on their webpage, but I can't find it just now.

Here is the page on our site about removing the locking pins on the window motors.

[s_forbes]

I like how all of the components for each module are mounted to a single plate, it makes for a nice simple assembly. The chassis is built in a great way to support each module too. Surprising lack of carbon fiber though!

What kind of control methods have your drivers experimented with, and what do they prefer?

Originally Posted by Drewit

Here is the page on our site about removing the locking pins on the window motors.

Side note: I love your team's website, it needs to be posted more often.

[jnicho15]

Originally Posted by s_forbes

Surprising lack of carbon fiber though!

After a dreadful experience last season with our arm mechanism (where we had a four-bar linkage clamp onto carbon tube which always slipped), our new captain plans to avoid carbon in most all cases except if weight is insanely important (like canburgalars) or low-shear loading applications.

[Chris Hapstack]

Originally Posted by Bennett548

Your model leaves out the friction force in the pivot bushing or bearing. You should also consider the extra toque that would be needed if the robot is getting pushed:

pushing force*height from pivot to ground*pivot bearing radius*pivot bearing coefficient of friction/pivot bearing radius/2= turning torque

That's a great point - thanks a bunch! I knew a pushing robot would increase the necessary turning torque, but couldn't figure out how to account for it. I like this model a lot.