TMQ AP4 - Following a Track (Waypoint)

TMQ AP4 Autopilot (AP4S10) 54 of 62 Version 4.96 9/10/2017
Following a Track (Waypoint)
The PID concept is described in the section above, “Keeping the Heading”.
However, in this case it is used for defining the direction of the boat, instead of
the rudder angle.
 Proportional value:
The bigger the cross-track error (XTE) and this proportional value, the
more direct will be the direction to steer to the track line. This
parameter makes the boat go faster or slower to the track line, but if it is
to big, will cause too much overshoot.
The adjustment of the gain for this parameter was explained in the
section “AP4 Special Modes” (display selection 915);
 Integral value:
This portion of the control adds up an offset in the desired heading of
the boat in order to compensate, for example, unbalanced load, wind,
tide currents, etc.
This value is adjusted selecting the special mode 925;
 Derivative value:
This parameter is intended for controlling the overshoot caused by the
proportional gain explained above. It must be increased only up to the
point it controls the overshoot. Too high values can make the boat
oscillate in its direction to the track line.
This value is adjusted selecting the special mode 925;
Procedure for setting these parameters:
If the boat is not following the track with the factory default parameters, the
following steps are suggested:
1. Initially, try to find an area without tide currents or other similar
disturbances;
2. Set the integral value (925) to 0;
3. Set the derivative value (926) to 0 or a small value such as 5.
4. Set the proportional value (915) between 20 and 40;
5. Make a track for the boat follow and start the trial. Adjust the speed of
the boat to the speed it will usually follow the tracks;