Talk:Autopilot

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The most recent additions to this article adds information but is desperately in need of editing. I'm not expert on this subject someone who's more knowledgable to edit it. Comatose51 02:34, 21 January 2006 (UTC)

1 Software Science or Control Engineering
2 Scope of Article
3 Globalhawk?
4 Aviation Autopilot Categories of Landing

[edit] Software Science or Control Engineering

It is not very informative to say that modern autopilots use software to control the aircraft, without specifying exactly what the software does, we might as well claim they work by magic.

It is more accurate to say that modern autopilots are implemented as computer software. As far as concepts are concerned this is mere implementation detail. The methods of autopilot design remains the body of knowledge called control engineering, which makes no assumptions concerning the implementation; the design may be implemented conceptually as analogue circuits, shift registers, computer code or even electro-mechanically. Gordon Vigurs 19:58, 29 May 2006 (UTC)

[edit] Scope of Article

The material has moved on from autopilots, which are basically systems to maintain straight and level flight, to inertial navigation, which serves to navigate specified classes of flightpath by generating autopilot commands. It would appear logical therefore to include ILS, TACAN, LORAN and Doppler navigation as well, but this would wander too far off the point.

In missile parlance, the autopilot serves to remove all the variability in airframe response due to altitude and Mach number, maintains stability with shifting centre of gravity position, and ensures a unity steady state gain. The input to the autopilot is typically a lateral acceleration command which is generated from the guidance (if derived from radiation emitted or reflected from the target) or navigation (if steered to a point in space).

In short, the autopilot is responsible for controlling the handling modes of the aircraft (short period pitch oscillation, and Dutch roll), but control of the trajectory is the responsibility of the navigation.

The sentence beginning 'modern autopilots use software' appears to rename the autopilot 'flight control system' and calls the navigation system the autopilot.

The various categories of 'autopilot' presented are different flight path controllers, all of which potentially employ the same innermost loops (e.g. autopilot proper), and are limited in scope to aviation.

As mentioned above, trajectory control of a missile is governed by a navigation law, typically proportional navigation or some form of line of sight (command to line of sight or beam rider). Furthermore, the autopilot does not necessarily control normal acceleration and bank angle: in skid to turn missiles, they control pitch and yaw lateral acceleration, in some cases they control angle of attack. In a space booster, it is the orientation in space which is controlled in order to steer the vehicle along a pre-defined optimal attitude program. In a satellite, or spacecraft, the autopilot serves primarily to control the orientation in space.

In all cases the 'autopilot' refers to the innermost set of loops, whose purpose is to render the vehicle response reasonably constant in the presence of disturbances and variations in the flight regime (typically altitude and Mach Number) and vehicle mass distribution.

The article would be more compact and accessible if autopilot, guidance and navigation were treated separately.Gordon Vigurs 07:27, 30 May 2006 (UTC)

Further, the Computer system details clearly identify one specific architecture. The detailed implementations in hardware/software can be very different. Surely the way many automatic flight control system contractors go about implementing their system is as varied as the number of aircraft and other flying bodies that are currently or formerly in operation. Handment 21:46, 20 March 2007 (UTC)

[edit] Globalhawk?

An anonymous user from the address 155.69.4.123 (talk • contribs) recently added the following note to the CAT IIIc entry in the Aviation Autopilot Categories of Landing section:

(Please look for Globalhawk, which might be the 1st to have such capabilty as of 2006)

"Globalhawk" presumably refers to the RQ-4 Global Hawk UAV. I have reverted the addition, as it was unreferenced and not written in an encyclopedic tone, but if someone with more knowledge about the subject than me could dig up a reference, the mention should presumably be included in some form. —Ilmari Karonen (talk) 01:03, 7 September 2006 (UTC)