Hi guys, i see that some people dont know what all those sliders for the autopilot in Juno new origins mean. Whilst it is not nearly as good as KSP's maybe this might help.
So according to the ksp wiki:
"Proportional means the S.A.S. module applies a turning-force that is proportional to the speed of rotation. In other words, the faster the ship is spinning, the harder the module tries to correct the spin.
Integral means the S.A.S. module increases the corrective force the longer the ship is off-target. Since the integral of speed is position, this corrects the vessel's heading (angle is the integral of angular velocity). Since the summed integral value is set to zero when SAS is turned on, the controller will attempt to lock the vessel's heading to whatever it was when SAS was turned on.
Derivative means the S.A.S. module takes the angular acceleration of the ship into account and tries to apply a force against it. So the faster the ship is going "into" the spin, the harder the S.A.S. module tries to stop it. This is supposed to dampen the action of the S.A.S module and prevent overshoot, as well as dampening any accelerating turn or roll."
If any devs can confirm this is how this works, that would be cool.
https://wiki.kerbalspaceprogram.com/wiki/SAS
From observing PIDs with planes, I find that the PID process variable is the current attitude and heading (and the setpoint, then, your target direction), not the craft's angular velocity as described on the KSP wiki.
Make a plane, set its pitch integral to 0, and give it a pitch to hold. If the PID applied to angular velocity, it would eventually reach the target pitch, just slowly; in Juno it'll always fall a few degrees short.
If you specifically want to know what the sliders mean, and are fine with a programmer's explanation: http://brettbeauregard.com/blog/2011/04/improving-the-beginners-pid-introduction/ The Beginner's PID taught me everything I know about PID controllers. But, to summarize...
Error = SetPoint - Process Variable
Proportional = Error, current frame
Integral = Error(frame1)+Error(frame2)+Error(frameN...) Or, the sum of all errors over time
Derivative = Error(current) - Error(lastFrame) Or, the rate-of-change of error
And the sliders you mess with are simple multipliers on each value.
That is the core of every PID controller ever implemented (with some variance in details). So if you play any other game with a PID controller that you can tune, that's what's happening under the surface.