Tuning The Autopilot For Optimum Steering Performance - Simrad AP70 Operation Manual

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Tuning the autopilot for optimum steering performance

Providing you have entered correct vessel type, length and cruising speed, you may not have
to perform further manual- or automatic tuning. Refer "Vessel confi guration" on page 56.
 Notes:
• If steering compass is magnetic type, perform any autopilot tuning steering East or West, as
this will yield the best-balanced parameters
• The speed during tuning should be as close as possible to cruising speed. Ensure that this is
set correctly and as described in "Vessel confi guration" on page 56
• Active work profi le that should be used during seatrial depends on vessel type.
- For displacement boats
- Planing boats will have to tune both
• All tuning should always be performed in open waters at a safe distance from other traffi c
Initial automatic learning process
Before doing any manual or automatic tuning the autopilot needs to learn the turn
characteristic of the boat. This is done in AUTO mode by making a major course change (min
90°) to port and starboard. For this test you may use the U-turn function (180°).
The autopilot will now fi nd the appropriate amount of rudder to maintain the set turn rate
during the turn. See also "Turn type and Turn value" on page 59.
When the automatic learning process is done, now proceed as follows to verify satisfactorily
steering:
1. Stabilize the vessel on a heading, and then select AUTO mode
2. Observe course keeping and rudder commands
- The autopilot should keep the vessel on the set heading within an average of +/-1 degree,
providing calm sea and wind
3. Make some small and bigger heading changes to port and starboard and observe how the
vessel settles on the new heading
- The vessel should have a minimum of overshoot (see example "Manual tuning" on page
61
If the autopilot is not keeping the heading satisfactorily or not making the turns satisfactorily,
you may now either try the Autotune function or go directly to Manual tuning.
 Note:
If the vessel is more than approximately 30 m/100 ft it may be unpractical to perform
Autotune, and it is suggested to proceed with manual tuning.
Both Autotune and Manual tuning should be performed in calm or moderate sea conditions.
Autotuning
When performing an Autotune, the vessel will automatically be taken through a number of
S-turns. Based on the vessel behavior, the autopilot will automatically set the most important
steering parameters (Rudder and Counter rudder). The scaling factors for the parameters are
set automatically as a function of the set boat type.
1. Stabilize the vessel on a heading
2. Set the speed is as close to cruising speed as possible
3. Start autotuning from the dialog
- The pilot will take control of the vessel. Autotuning may take up to 3 minutes to complete
After the autotuning is completed the autopilot will return to STBY mode, and the rudder
must be controlled manually.
 Note:
Autotuning can be stopped at any time by selecting Cancel.
System confi guration | AP70/AP80 Operator Manual
NORMAL work profi le should be used
LO SPD and HI SPD work profi les