CTRE Swerve Generatpr Questions

[acastagna]

I’m looking at the CTRE SwerveWithPathPlanner example and I have a few questions:

1. What is kCoupleRatio? The comment states “Every 1 rotation of the azimuth results in kCoupleRatio drive motor turns” . Does that mean if we are rotating in place with the modules at +/- 45 degrees how many drive motor rotations to make the robot do a full 360 degrees?

2. The steer motors use open loop voltage control. Can we change that to motion magic by changing steerClosedLoopOutput to motion magic and specifying the motion magic constants in the setup?

3. Is the template posted on github similar to what we would get from the Tuner X generator? We haven’t had a chance to use the Tuner X generator - we plan to try it next week.

Thanks for any input. There’s certainly a lot of awesome changes to process this year!

[J.F]

Tuner X Swerve Generator Failed

Hello, I was trying to use Swerve Generator to create the code. However, in the first of this priod, there was a error about version. [410373448_714629410810787_6593329084814877280_n] I reviewed all the devices, and the versions were all right. [410456446_1815461805549601_6301099618968097395_n] [410202639_919645229651224_4751139053931534948_n] I was not sure about what is the pronlem, so I ignored this this mistake and just went to next step. Then other problems happened, the fisrt one w…

You can check this topic, I think you can get a answer for question 3.

[acastagna]

Thank you. Looks like the limelight, pathplanner and logging additions were the only big differences you found.

[LHACK4142]

@acastagna

• What is kCoupleRatio? The comment states “Every 1 rotation of the azimuth results in kCoupleRatio drive motor turns” . Does that mean if we are rotating in place with the modules at +/- 45 degrees how many drive motor rotations to make the robot do a full 360 degrees?

Keep in mind I am very much a noob whose only credential really with swerve is having built a LEGO swerve module and having glanced at some swerve CAD, but I believe that when you change a coaxial swerve’s heading, its main drive wheel turns too. It’d make some sense to me if kCoupleRatio is related to that.

[reimerit]

This is correct. The Couple ratio is the amount that the wheel turns per rotation of the module’s heading. This is because on a coaxial module the drive and turning gears are mechanically linked, so when the module turns, the drive gears turn in reference to it by some amount.

[acastagna]

Ok - that makes sense. Thanks !

[arm64]

I’m currently working on converting the CTRE TunerConstants generated file to be compatible with Advantagekit swerve, but I am yet to find an equivalent on of couple ratio. Any ideas?

[reimerit]

I could be wrong on this, but I believe any swerve base using the WPILib Swerve kinematics has it baked into the internal math of the swerve kinematics class. I’ll double check this as soon as I get a chance to look at the code again.

[bathtubed]

I don’t see how this could be possible without passing in the ratio in question to the WPILib swerve kinematics library.

[arm64]

yeah, as far as I see, there is nothing in advantagekit swerve that takes any “couple ratio” into anything.