Paper Info
Title
Phasing Of Periodic Tasks Distributed Over Real-Time Fieldbus
Abstract
In designing a distributed hard real-time system, it is important to reduce the end-to-end delay of each real-time message in order to ensure quick responses to external inputs and a high degree of synchronization among cooperating actuators. In order to provide a real-time guarantee for each message, the related literature has focused on the analysis of end-to-end delays based on worst-case task phasing. However, such analyses are too pessimistic because they do not assume a global clock. With the assumption that task phases can be managed by using a global clock provided by emerging real-time fieldbuses, such as EtherCAT, we can try to calculate the optimal task phasing that yields the minimal worst-case end-to-end delay. In this study, we propose a heuristic to manage the phase offsets in the distributed tasks to reduce the theoretical end-to-end delay bound. The proposed heuristic reduces the search time for a solution by identifying time intervals where actual communication occurs among inter-dependent tasks. Furthermore, to analyze the distribution of end-to-end delays in different phases, we implemented a simulation tool. The simulation results showed that the proposed heuristic can reduce worst-case end-to-end delay as well as jitter in end-to-end delays.
Year
DOI
Venue
2017
10.15837/ijccc.2017.5.2894
INTERNATIONAL JOURNAL OF COMPUTERS COMMUNICATIONS & CONTROL
Keywords
Field
DocType
task phasing, end-to-end delay, real-time, fieldbus, EtherCAT
End-to-end delay,Heuristic,Synchronization,Computer science,EtherCAT,Phaser,Real-time computing,Jitter,Periodic graph (geometry),Distributed computing,Fieldbus
Journal
Volume
Issue
ISSN
12
5
1841-9836
Citations 
PageRank 
References 
0
0.34
0
Authors
4
Name
Order
Citations
PageRank
Sang-Hun Lee116925.36
Hyun-Wook Jin238341.06
Kanghee Kim322320.24
Sangil Lee411.03