US 6,374,144 B1 · Method and apparatus for controlling a system using hierarchical state machines

Abstract

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.

Claims31

Dependent claims

A system for controlling a device having a plurality of interconnected subsystems coupled in a hierarchy, with subsystems at a given level in the hierarchy being included in a subsystem at an immediately higher level of the hierarchy, the system comprising:

a plurality of hierarchically coupled state machines, with at least one state machine associated with each of the hierarchically coupled subsystems;
means for evaluating the states of the state machines for each of the hierarchically coupled subsystems in an order defined by the hierarchy;
and
a scheduler for scheduling an order of execution of the plurality of subsystems during operation of the controlled device and determining the order of execution of the subsystems in the hierarchy in response to a total execution time of each of the subsystems of the device and in response to a selected number of cycles for execution of the device,
wherein a time period is associated with each of the subsystems for indicating how often the associated subsystem is to be evaluated during operation of the controlled device, and wherein the order of execution of the subsystems is determined in response to the associated time period of each of the subsystems.

2 more elements

The method for analyzing a system having a plurality of interconnected subsystems coupled in a hierarchy, with subsystems at a given level in the hierarchy being included in a subsystem at an immediate higher level of the hierarchy, each one of the interconnected subsystems being associated with a corresponding one of a plurality of hierarchically coupled state machines, the method comprising the steps of:

evaluating, for each subsystem, a state of the associated state machine, wherein an order of evaluation of the associated state machines is determined in response to an order defined by the hierarchy of the plurality of interconnected subsystems;
and
scheduling the execution of subsystems in the hierarchy of state machines, wherein associated with each of the subsystems is a time period for indicating how often the associated subsystem is to be evaluated, and wherein the step of scheduling includes the step of determining the order of execution of the subsystems in response to the time period of each of the subsystems, and wherein the step of determining the order of execution is firther performed in response to a total execution time of the system.

A control system for controlling a device comprising:

a processor, coupled to the device, the processor comprising:
a memory for storing signals associated with the device, where the signals are received from the device and forwarded to the device during operation of the device;
a hierarchical data structure comprising a plurality of hierarchically interconnected subsystems representative of the operative functions of the device, wherein each of the interconnected subsystems is represented by at least one object;
means for forwarding the signals to the hierarchical data structure;
means, responsive to the signals, for updating states within the hierarchical data structure in a controlled manner, wherein the means for updating the states within the hierarchical data structure in a controlled manner includes means for evaluating states of objects in ascending hierarchical order and in descending hierarchical order during an execution cycle;
and
a scheduler, for scheduling the execution of each of the objects of the hierarchical data structure during operation of the device, wherein scheduling is performed in response to an execution protocol of the control system;
wherein each of the at least one objects further includes at least one of either a state machine or a data flow diagram, and wherein the execution protocol of the control system dictates an order of execution of the state machines or data flow diagrams of the hierarchical data structure.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for controlling a system using hierarchical state machines

Life of this patent

Method and apparatus for controlling a system using hierarchical state machines

Life of this patent

Abstract

Claims31