Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Aircraft on ground path following

Aircraft on ground path following

Aircraft on ground path following

Hi Everyone,

I am new here but I need some guidance for my project which involves having an Airbus A320 following a pre-defined path around an airport.

Now, I have a set of X-Y coordinates which describe a 180 degree U-turn type of path and I have managed to calculate steering angles for the nose wheel of the plane using the wheel base and 3 consecutive points along the path. However, I am struggling to solve how the control logic would dictate which point on the path is the desired/target point if the plane is say... in a random position which is not on the path, but close to the path.

The aircraft assumes 3 degrees of freedom

Has anyone done anything like this before?


RE: Aircraft on ground path following

Look at agricultural solutions. A problem working large fields with very wide implements (seeders, spreading fertilizer, spreading chemical treatments etc.) is to avoid overlapping and to avoid missed sections.
Some systems, after programing, will automatically steer a tractor and implement to cover hundreds or thousands of acres with-out overlap, missed sections or contact with fences or water holes.
With the basic system, at the end of a row, the driver takes control and turns the rig around under human control. When the rig crosses the next path to be followed, the automatic system takes over steering the rig.
Take a look at some of these systems. It may be helpful to see how others have solved similar problems.

"Why not the best?"
Jimmy Carter

RE: Aircraft on ground path following

Either the predefined path is the centerline of the available taxiway (and you have to assume it's wide enough for the landing gear) - so program the center of the gear pattern to stay on the centerline, or it's two "paths" defining the boundary and you need to program so the wheels stay inside the lines.

RE: Aircraft on ground path following

There are a couple of ways to do this.
One is to use super imposed moves as a function of the motion of a virtual target position.
The other is to compute a polynomial that gears to the virtual target. This polynomial keeps track of the actual position, gear ratio and gear ratio rate as function of the virtual target's position, velocity and acceleration. The polynomial must end up at the same position as the target position with gear ratios set to 1 and gear ratio rates set to 0 so the plane's actual position, velocity and acceleration match the virtual position velocity and acceleration.
There is a lot of calculus using the chain and product rule.

Peter Nachtwey
Delta Computer Systems

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close