F2010C202
Measurement and Analysis of FlexRay Synchronization Performance
Since the 1970s, electronic systems in automotive systems have increased in numbers and have gradually replaced mechanical systems. The increase in the number of electronic systems has necessitated the use of wires to connect each of these electronic systems. As a result, reduce wire harness has become important with an exponential increasing of electronic systems. Therefore, the automotive industry develops multiplexed communication protocol such as LIN and CAN. With progress of technology, the demands of automotive systems are varied. Especially, in order to meet new requirement such as x-by-wire, LIN and CAN cannot support adequate performance for x-by-wire. Therefore, the automotive industry develops FlexRay. FlexRay use TDMA (Time Division Multiple Access) mechanism for static segment and Flexible TDMA mechanism for dynamic segment. As FlexRay operate based on TDMA mechanism, it need global time basis between nodes connected by FlexRay network. To support global time basis, FlexRay support synchronization algorithm in controller chip such as MFR4200 and MFR4310. FlexRay synchronization algorithms support offset correction algorithm and rate correction algorithm to synchronize local clock of nodes that connected by FlexRay. As FlexRay uses TDMA mechanism (or flexible TDMA), the global time basis affects whole protocol performance of FlexRay. Hanzlik present the synchronization performance of FlexRay is affected by clock drift rate in his paper [1]. They simulate FlexRay synchronization algorithm using SIDERA based on oscillator characteristics. They do not consider other factors that can affect synchronization performance of FlexRay. Therefore, we analyze the synchronization performance of FlexRay about following facts and derive the formula for calculate synchronization performance of FlexRay network. ▪ Performance of oscillator ▪ Location of FlexRay controller (within MCU or not) ▪ Number of nodes in a cluster ▪ type of topology ▪ Length of wire ▪ Version of FlexRay controller (MFR4200 and MFR4310) ▪ Filter is used or not ▪ Erroneous environment using FlexRay stress ▪ Performance of host controller(MCU)
[1] A. Hanzlik, "A case study of clock synchronization in FlexRay," technical report in real-time systems group, May 2006. http://www.vmars.tuwien.ac.at/
This abstract is supplemented by a PDF, which can be viewed here.
Poster presentation: Test, simulation and calculation methods of vehicles and components