METHOD AND APPARATUS FOR CONTROLLING A SYSTEM USING HIERARCHICAL STATE MACHINES

A method and apparatus for controlling complex systems includes hierarchically coupled subsystems representing operative functions of the system. The hierarchically coupled subsystems are coupled to collect command data from a user and signal data from the system. Each subsystem may include one or more state machines and one or more digital signal processing and conditioning unit (DSPCU) objects. The DSCPU objects accept process commands and convert control system signals into states for further processing by the state machines. Associated with the DSPCUs of each subsystem is a data flow diagram for dictating an order of flow of commands and signals at the DSPCUs. A method of controlling the system represented by the hierarchically coupled subsystems schedules the execution of the subsystems according to an execution protocol. According to the execution protocol, for each cycle of execution of the system, the hierarchically coupled subsystems are first analyzed in ascending order of the hierarchy, with DSPCU objects being analyzed in data flow order before state machine objects, and then in descending order of the hierarchy, with state machine objects being analyzed before DSPCU objects. During the ascending execution of the hierarchy, signal data received from only those objects that are relatively lower in the hierarchy are used to update the state of any given object. During the descending execution of the hierarchy, command data received from only those objects that are relatively higher in the hierarchy are considered when updating the state of any given object.