pic: Average Swerve Module


#1



Prototype module, the first of four that will populate our test chassis soon. 5.7 lb as shown including two 775 motors. No, it is not differential in this stage of development. Plan is to steer at the large gear that surrounds the main bearings, using a Snowblower motor. Encoder, Talons, and slip ring still to be added on top, using a printed structure.

We don’t have any plans to use this concept on a competition robot, yet. 2019 may or may not be the right year.


#2

12 motors dedicated to a drivetrain. Never thought I’d see the day.


#3

Me too. A robot with that many drivetrain motors will be using a lot of pneumatics.

We have only committed to prototyping this during the off season. It may or may not see official FRC carpet, but will definitely get driven in practice. Will provide updates including CAD and video as the project moves along.

Thanks are due and gratefully given to swerve experts in several places, including 16, 2451, 2767, and AndyMark, for providing helpful design critique before we started to cut metal.

More details to follow…


#4

Can you talk about this choice a little bit? It seems like an odd choice to me to use a motor with such low power.


#5

The Snowblower motor’s free speed is 100 RPM (1.67 rev/sec) and its stall torque is 70 lbf-in. Its stall current is 24 Ampere.

We plan to fit the Snowblower motor with a 72 tooth drive gear, to engage the 84 tooth steering gear on the swerve module.

Separation between the dual wheels is about 2 inch, and each module will nominally support about 38 lb (one-fourth of robot weight), so torque-to-turn against scrub will be about 38 lbf-in. That would require about 47% of Snowblower motor stall torque, so 11 Ampere and 0.89 rev/sec.

That may be too much load. If it is we will use a more powerful motor. Otherwise, we like the Snowblower motor’s low profile and weight.


#6

This could also work with 9 motors on a round/triagular base.


#7

We have another idea along those lines.


#8

I didn’t even need to click that link to know where it leads…