how would one best invoke a reverse action control function, as required in industrial controllers for working with fail open and fail close control valves?
An autopilot use heading information from a fluxgate compass so of course that will be used as a feed-back. However in my understanding of an autopilot it usually consists of two cascaded loops. The first one for heading and the other one for setting the rudder position. The first one use heading as feed-back and the last one a "rudder feed-back unit". Some autopilot manufacturer has taken away the need fro that last unit and I just wander how that can be done.