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Unread 21-01-2017, 21:20
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Paul Copioli Paul Copioli is offline
President, VEX Robotics, Inc.
FRC #3310 (Black Hawk Robotics)
Team Role: Engineer
 
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Re: Velocity Control - Battery Compensation Term

Quote:
Originally Posted by Tom Line View Post
When doing velocity control with the talon srx's, the velocity you get from your feed-forward term is going to be affected by battery voltage. Has anyone experimented or used a battery offset term to correct for this? Is it worth it?
Tom,

The I gain is for things like that. We use I and P for velocity control and as long as you design your gearbox / motor combo with enough headroom then the I and P can compensate. We design our speed controlled devices to operate at 60% duty for the ideal situation. For example, if you want your shooter to go 2500 RPM, it better hit that speed at 60% - 70% duty. This way, the I and P gain can do their job. When testing without speed control, if you set your motor command at .6 or .7, then you should be able to score your game object from the desired shooting spot with a full battery and one ball at a time. At least, this is what we do.

Paul
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In full disclosure I am the President of VEX Robotics, a division of Innovation First International.
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