Hello,
We are using a flywheel this year on our robot. We wanted the flywheel to reach a target velocity. We were wondering if we needed to account for a gear ratio anywhere in our code or when we tune the flywheel in SysID? We use Falcon 500 motors and its internal encoders. Our original thought was that we didn’t need to account for the gear ratio because this is velocity, not position control, but we could be wrong. Below is a screenshot of our current SysID layout for tuning our flywheel.
While I don’t know much about SysID, you were correct in assuming that neither SysID or need to know about any gear ratio on your flywheel for velocity. It might be necessary to input such numbers into SysID if you set a conversion factor in your code in order to work with more sane units, however.
If you what your output to reach a target rotational velocity, AND there is any sort of gearing or belt reduction between your motor and the eventual output, then, yes, you have to take that into account. You can use the encoder on your motor, but will then have to apply some math to determine the eventual output rotational velocity.
Yes, our motor is connected to our flywheel through gearing and belts. Therefore, it looks like we’ll need to account for a gear ratio. Should we divide the velocity by the gear ratio?
Let’s say that you’re doing a 1:6 ratio, then your output velocity will be 1/6th of your motor velocity. Let’s say your target is 1000 rpm. You’d need your motor to go 6000 rpm. Whether you use division or multiplication is up to you.
Note that @CEF’s statement about needing to account for gearing is correct because you specified that you were using the Falcon’s internal encoders. If your encoder were attached to the flywheel axis, no such adjustment would be needed.
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