The inspection is subdivided into different phases, these are:
Searching, Approach, Following, Turn and Finish.
During the phase Search, the OIS module is activated, but has
no vehicle control. It is analyzing the object detection module data
for the object which has to be inspected using the data of object
identification module and the information from the mission plan.
When the information match, the OIS module requests the vehicle
control from the mission control module and the inspection task
enters the next phase.
When the inspection object was found the phase Approach
begins and the vehicle adapts its course so that it starts to follow
the wall as shown in Fig. 12. These calculations will be done until
the vehicle reaches the inspection distance to the wall.
The phase Following is activated, when the vehicle reaches the
inspection distance to the wall during the phase Approach. The OIS
module calculates new virtual target points on inspection distance
to follow the structure of the wall (Fig. 13).
The calculation of the virtual target points is described in detail
in Section 5.2 and illustrated in Fig. 14.
The inspection is successfully finished, when the vehicle leaves
the inspection area and has inspected the whole surface of the
object, below the water line, which has to be inspected. When the
OIS module loses track of the wall, the inspection is also finished,
but marked as unsuccessful. The OIS module informs mission
control and returns the vehicle control.
The VGS guides the vehicle to the next inspection object, and
OIS will be activated again, or returns to the recovery area.