servo jitters

[nitneylion452]

Originally Posted by jon-s

When the servo jitters (I don't recall any sound), it moves back and forth, up to about 50 degrees. It does this regardless of what position it starts in. It has done this on both of our robots.

It is plugged into the sidecar and should have a jumper on it. The servo moves a thin 2 inch long arm. I think this is the first year our team has used the servos, they've only been moved maybe a dozen times. People have backdriven them, but not very often. The wires and cable cross at about 60 degrees to each-other.

50 degrees to either side is a lot of motion to be a jitter. The HS-322HD's full range is only ~170 degrees (based on us eyeballing it). You should take a look at your code and make sure you aren't sending conflicting commands. If everything looks ok, try a new servo. You can order a HiTec HS 485HB which offers an additional 30oz-in of torque and is rated at 3.9 watts (322 is only 2.5).

As far as the jumper suggestion, that cannot be the case. If there were no jumper, the servo would not get power and not move at all.

EDIT:

It is also worth noting that (in Java, I'm not familiar with the other languages esp LabView) the method to tell the servo where to go is called setSpeed(). This is very misleading. setSpeed() tells the servo where to go, not how fast to move, so calls to it with different values, like 0.0 and 0.5, will cause it to fluctuate between the two positions and may be the root of your problem.