A finite state approach was developed by CMU in their autonomous windrower
(Hoffman, 1996). Primary states of the machine triggered different behaviors or
operations. Some basic states defined which side of the harvester was uncut crop,
identified the proximity of a turn, and the implemented of turning functions. In
each state of operation the machine performed one or more behaviors. For
example, harvesting a rectangular field of alfalfa in a simple serpentine pattern
required combinations of the following states with associated behaviors: