Event-Triggered Design of Networked Embedded Automation Systems
Chidi H. Anozie · OhioLink ETD Center (Ohio Library and Information Network) · 2010
Systems that interact with the physical world can be designed in either an eventtriggered (ET) paradigm or a time-triggered (TT) paradigm.Most real-time systems today are designed in the TT-paradigm because it is easier to achieve predictable performance.However, when some critical aspect of the system changes, designs based on the TT-paradigm must be completely revised.Modern application require systems to be flexible and reliable.Since the event-triggered systems are fundamentally designed as a colletion of loosely coupled local entities, it was interesting to investigate the predictablity of ET-systems.This investigation focused on a ET-design for operating a MicroFactory, which is a physical simulation of a discrete assembly system.The design was implemented and evaluated using a collection of networked embedded microcontrollers.Common tasks in a discrete assembly environment were captured as a collection of primitives.These primitives were redesigned and implemented in the ET-paradigm.Experimental results collected reflect the performance at the level of a single node and at the level of the system.Results were studied in comparison with similar ones obtained using a design that was based on the TT-paradigm.In the future, principles and techniques for reconfigurability can be incorporated in the proposed framework.iii 5.3 Data gathered from the remote response primitive experiment . . . . .5.4 Data gathered from the request/response primitive experiment . . . . .5.5 Data gathered from the publish/subscribe primitive experiment . . . .5.6 Data gathered from the multihop remote response primitive experiment 5.7 Data gathered from the multihop request/response primitive experiment viii