Grex Project

3.2 Team Initialization Process
The first active part of the Team Handler builds the Initialization Process. Within these routines a first
level of cooperative coordination is realized which is controlled from the Team Handler of the leading
vehicle. Like the other critical parts of the presented structure the single steps of the initialization are
predefined and implemented as state machine.
Fig.4: Main process diagram of the Team Handler with focus on Team Initialization Process
The Initialization Process can be divided in two parts, see Fig.4. On the left side, there are the routines
that initialize the vehicle internal structures like the Team Navigation Module with specified data
from the Data Management or from the vehicle itself. On the right side, functionalities which setup
the team data are implemented. The process of the second part depends if the current vehicle is the
leading one or just a team member. While the Team Handler on the leading vehicle is responsible to
collect the group data to prepare the start of the mission, the member vehicles have to send required
data. After all parts are initialized in the correct way the main process loop, including Mission
Monitoring and Mission Replanning, will start.
3.3. Mission Monitoring
The main control part of the Team Handler structure builds the Mission Monitoring. Based on the
rational behavior model in conjunction with a global state machine this part generates commands for
replanning or information for other modules. Thereby we distinguish between two kinds of Team
Handlers in general. The Team Handler on the leading vehicle and the team handling structures on a
member vehicle. Both are realized identical while the leading vehicle has to fulfill some additional
tasks like the coordination of the group initialization process and the path re-/planning of complex
maneuvers. The role as leading vehicle can be transferred to another vehicle during the mission and
depends on the parameters which were set during the offline planning process.
Fig.5 gives an overview of the main workflow within the Team Handler structure from a more
practical point of view. The focused area points the major tasks of the Mission Monitoring including
the different layers specified by the Rational Behavior Model (RBM). The RBM is a standard
approach for hierarchical control structures in research on mobile robotics, Kwak et al. (1993). Every
layer is realized by at least one function which creates proposals to manipulate the behavior of the
current vehicle in order to activate and keep a team manner within the group of vehicles taking part on
a mission. Thereby the influence of the different layers gets smaller from the Strategic Level down to
the Executive Level.
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