How The Ontrac2 System Works - Ag Leader EDGE User Manual

• Heading Aggressiveness
How accurately the OnTrac2 system's will control the heading or the direction of the vehicle when on the
AB line. The higher the Heading Aggressiveness Value the more accurately the system will try to control
the actual heading of the vehicle. Heading Aggressiveness should be set as high as possible. If it is set too
high, the OnTrac2 system will try and control the vehicle's heading too accurately, and will oscillate across
the AB line of the OnTrac2 Mechanical Drive Unit.
Note: Heading is very important to the vehicle's ability to maintain an AB line, as it adjusts the vehicle's
direction and future location.
• Cross-Track Error
Cross Track Error adjusts how close the vehicle holds to the AB line. Increasing Cross Track Error will
improve or decrease the amount a vehicle is off the AB line. If it is set too high, the OnTrac2 system will
oscillate across the AB line.

How the OnTrac2 System works

Imagine three men in a special tractor cab, called 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
Steers the tractor left and right.
• Heading'
Uses a compass and measure the difference between the tractor's heading and the AB line heading.
• Cross Track
Uses 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 headed.
• Steering listens to Heading and Heading listens to Cross Track, which issue commands on how far left
or right to steer the tractor so that it stays 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.
• Cross Track also tells Heading which in turn tells Steering how much to steer the tractor left and right in
order to minimize the tractor's distance from the AB Line, or its offline distance.
- Cross Track'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 OnTrac2 system is
driving on the AB Line. The OnTrac2 system comes out of Line Acquisition Mode when the vehicle Cross
Track Error is approximately less than six inches for approximately two or more seconds
Note: 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.
Note: Because of the sequential nature of the 3 men, Cross Track talks to Heading which talks to Steering,
in is very important to adjust them in order, Steering first, Heading next and then Cross Track.
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