David Megginson said:

> Ampere K. Hardraade wrote:
> > One explanation for the violent maneuvers that I thought of is this: as the 
> > distance between the plane and the waypoint decreases, the accuracy required 
> > in the course calculations increases.  Since it takes time for the autopilot 
> > to respond, and takes even more time for the plane itself to respond to the 
> > commands of the autopilot, the plane will never align itself perfectly with 
> > the waypoint.  Hence, the autopilot will keep trying to "catch" the waypoint 
> > until the very last moment, thus causing the violent maneuvers.
> Yes, that happens with student pilots as well -- localizers, VORs, you name 
> it all become very sensitive as you get close.
> > One solutions to the above problem is to pop the waypoint when the plane is 
> > still some distance away, thereby preventing the autopilot from making all 
> > those course adjustments.
> Or simply increase the allowable error at close distance, or use some other 
> kind of filtering function.

There is a look ahead filter in the current autopilot code.  It is being used
to anticipate ILS radial interception for the 747.  Maybe thrust control too.



Flightgear-devel mailing list

Reply via email to