Environmental Engineering Reference
In-Depth Information
5.5 Act Technologies
The action portion of the autonomy cycle is responsible for implementing the
choices made by the plan portion of the cycle. The actions interact directly
with the operating environment and must be customized to the problem do-
main.
The most obvious action technologies are the actuators used by robots
and immobot agents. Actuators are devices that are directly coupled in the
operation environment and are able to make some change when activated.
Examples include opening a valve, moving a drive train, or starting a pump.
Being physically connected to the real world, actuators are subject to the
wear and tear due to age and potential damage caused by the environment.
Wear and tear can cause actuators to have complex failure pathologies, and
robust systems are designed to detect these failures and recover. Since actua-
tors modify the operating environment, designers must ensure that actuator
actions do not have negative side effects for the agent or the environment.
Communication is a different form of action. Agents use it to share world
views, negotiate options, and direct subordinates. Usually, the communication
is transmitted over a network. The messages can be sentences in a formal
language or can be the exchange of computer data structures.
In software agents, all actions are represented as some form of communica-
tion to the subsystems being controlled by the agent. These communications
cause the controlled system to begin some internal process or modify a process
that is underway. Examples of these actions would include sending email to
the owner, beginning a database search, canceling a buy order, or sending a
work request to another agent.
5.6 Perception Technologies
Perception is the activity of sensing and interpreting the operating environ-
ment. Like the action technologies, perception technologies are tightly coupled
to the problem domain.
5.6.1 Sensing
Sensing is the process where some attribute or attributes of the environment
are measured. Many types of sensors exist, from the simplest switch to complex
multi-spectral image detectors, and they use a wide range of technologies to
measure the environment.
In many cases, the sensor will take several steps to convert the sensed
attribute into electronic signals that can be interpreted by computers. For
example, a microphone converts the sound energy moving in the air into tiny
vibrations in a mechanical system. These mechanical vibrations are then con-
verted into electrical energy usually using piezo-electric or electromagnetic
devices.
