[Geek 2.0]

So, I've worked with PID Loops before, although I've never got them working well. I'm wondering a few things:

1. What's the best tuning method? It's especially difficult to tune when you are tuning your drive wheels with encoders to go a specific speed.

2. As far as I know, if I tune free running wheels, the PID values won't work when the wheels are on the ground. Is this true? I have a calculus background, which supports this idea, but I want to confirm with you guys.

3. Is it worth using PID loops on drive wheels?

Thanks!