Tuning PID Constants Over a Range

[wesleyac]

Originally Posted by wireties

An arm-like mechanism that takes much more power to move up than down is also very difficult to tune - so balance the motion against gravity with a gas shock or surgical tubing.

Just want to point out that this is probably easier than you think to control - you can do feed forward by applying voltage proportional to the cosine of the angle of the arm to cancel out gravity, at which point it becomes a (approximately) linear system, that is fairly easy to control (Although there are still some considerations to be taken with the difference between going up and down). A FF + PID arm is much easier to control than one with surgical tubing or a gas shock, imo.

The point that programming can only do so much is definitely valid, I just wanted to point out that arms aren't too difficult, as that's what we spent our season doing