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View Full Version : [FTC]: LabView servo issue


Abra Cadabra IV
31-01-2009, 20:10
My team's almost done with programming our robot in LabView and we've hit some bizarre snags.

Our bot has an arm, a pivoting bucket, and a claw. Our arm is controlled by two motors, our bucket is controlled by two servos (y-cabled together and facing the same direction), and our claw is controlled by one servo opening/closing the claw and one rotating the claw itself. We have code installed that, if a button is pressed, will move our arm to a certain location (through use of encoders) and will also rotate the bucket to a certain position. We have four buttons programmed like this, to move the arm and bucket to four distinct positions.

However, when we do this:
-Our motors often do not stop at the same time and one will keep going for 1/4 to 1/2 rotation longer
-The servos on our bucket twitch back and forth uncontrollably and are very slow in moving to the position we tell them to
-The servos on the claw also move when the buttons are pressed, even though they are most definitely NOT called in the program

What could be causing this? We've downloaded all the updates. Our servos and motors are running in the same direction and we've confirmed that they're not fighting each other. It's truly confusing.

Also, do the other programming languages have these same problems or is it just LabView?

jbbjjbt
02-02-2009, 13:44
My team's almost done with programming our robot in LabView and we've hit some bizarre snags.



However, when we do this:
-Our motors often do not stop at the same time and one will keep going for 1/4 to 1/2 rotation longer
-The servos on our bucket twitch back and forth uncontrollably and are very slow in moving to the position we tell them to
-The servos on the claw also move when the buttons are pressed, even though they are most definitely NOT called in the program

What could be causing this? We've downloaded all the updates. Our servos and motors are running in the same direction and we've confirmed that they're not fighting each other. It's truly confusing.

Also, do the other programming languages have these same problems or is it just LabView?

We've been through a lot of these issues.
On thing to try is to send 0 position to the servo motors you are not moving. I.E., if you want to move servo motors 5 and 6 to 127, send 0 to servo motors 1 - 4 and 127 to servos 5 and 6. This should be the default in the command but somehow can get easily messed up. Also for 2 servos facing the same direction you may need to send different values to get them to move to the same place.