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Unread 24-05-2010, 16:46
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Re: Swerve vs. Mecanum Programming

Quote:
Originally Posted by Alan Anderson View Post
If the system you're controlling does not have appreciable inerta and/or a slow response to changes in the control signal, a simple "full on"/"full stop" scheme can work fine. For example, a window motor usually stops as soon as you remove power, without significant overshoot. That's typical of a worm gear system.

On the other hand, if you're moving a massive mechanism around, you definitely want to slow it down on its way to the target position. Stopping it abruptly can lead to extreme stress on the gears (as demonstrated well by the teeth being stripped off a large sector of a heavy gear on the TechnoKats 2004 robot's arm by the team's programming mentor a few minutes before the pre-ship open house was to begin).
You may notice that there is a "slow down range" in my code. I have done multiple ways of programing a swerve as apalrd has described. I used this version because we weren't getting enough power out of our motor at low speeds and the swerve modules weren't turning very fast any way. We did not actually use a swerve drive this year on our robot, we wanted to but we didn't have weight, but we tested a swerve drive with a globe motor. I can post my other simple code for a swerve that subtracts but we also used this VI for actually moving the entire robot (comparing encoder to the position we want to go to) and we didn't want to slow down as we got to the ball instead we wanted to move, at full speed, to right before the ball and then slow down and search for the ball. It worked really well.