Ag Leader ParaDyme Setup and Advanced Tuning Guide - Manual (Page 6)

2202 South Riverside Drive, Ames, IA 50010
Phone: 515‐232‐5363 Internet: http://www.agleader.com
25‐Jun‐10 ‐ Rev E
6
How the ParaDyme Steering Controller works
Imagine three men in a special tractor cab, named Steering, Heading and Cross Track. The cab on the
tractor is special because none of the three men can see outside the windows of the cab. Inside the cab,
each man has a unique job and end goal:
• Steering’s job is to steer the tractor left and right.
• Heading’s job is to use a compass and measure the difference between the tractor’s heading
and the AB line heading. Heading also tells Steering what curvature (radius) to steer the
machine.
• Cross Track’s job is to use a measuring tape and to measure how far offline the tractor is
from the AB line.
These three men interact with each other to steer the tractor in the following way, keeping in mind
they cannot see their steered wheels or where they are heading. See Figure 3 ‐ Inside the ParaDyme
Controller
• Steering listens to Heading and Heading listens to Cross Track, which issue commands on how far
left or right to steer the tractor to keep it on the AB line.
‐ Steering’s goal: To steer the tractor in a responsive manner, but not in a jerky or lazy way.
• Heading tells Steering how to steer the tractor left and right in order to minimize the difference
between the tractor’s heading and the AB Line heading.
‐ Heading’s goal: To minimize the difference in the tractor’s heading and the AB Line heading.
• Cross­Track also tells Heading which in turns tells Steering how to steer the tractor left and right
in order to minimize the tractor’s distance from the AB Line, or it’s offline distance.
‐ Cross­Track’s goal: To minimize the distance between the tractor and the AB Line.
• Line Acquisition Mode is the mode in which the steering controller is in when the ParaDyme system
is driving the vehicle to the AB Line. The ParaDyme system comes out of Line Acquisition Mode when
the vehicle Cross Track Error is approximately less than 6 inches for approximately 2 or more seconds.
NOTE 1: During Line Acquisition (when the vehicle is acquiring the AB line), Steering ignores
Cross Track Error, so only Steering and Heading are responsible for getting a vehicle to the AB
Line.