Example: An abstract follow-corridor behavior

Example: An abstract follow-corridor behavior

The move to goal example used a single motor schema with a single perceptual
schema. This example shows how a potential fields methodology can
be implemented using schemas. In the corridor following example in Ch. 4,
the follow_corridor potential field consisted of two primitive fields: two
instances of perpendicular to the walls and one uniform parallel to the
walls. The follow_corridor field could be implemented in schemas in
at least two different ways as shown in Fig. 5.2. In one way, each of the
primitive fields would be a separate motor schema. The follow corridor motor
schema would consist of the three primitives and the coordinated control
program. The coordinated control program would be the function that
knows that one field is perpendicular from the left wall going towards the
center of the corridor, which way is forward, etc. They were summed together
by the coordinated control program in the behavioral schema to produce
a single output vector. The perceptual schema for the follow corridor
would examine the sonar polar plot and extract the relative location of the
corridor walls. The perceptual schema would return the distance to the left
wall and the right wall.
Another way to have achieved the same overall behavior is to have follow_
wall composed of two instances of a follow wall behavior: follow_-

wall (left) and follow_wall(right). Each instance of follow wall
would receive the sonar polar plot and extract the relevant wall. The associated
class diagram is shown on the right in Fig. 5.2.
In both implementations, themotor schema schemas ran continuously and
the vectors were summed internally in order to produce a single output
vector. Since there were multiple motor schemas, the coordinated control
program for follow-corridor is not null as it was for move-to-goal. The vector
summation and the concurrency formthe conceptual coordinated control
program in this case.