Controller area network with offset scheduling: improved offset assignment algorithms and computation of response time distributions

Download

index.pdf

Date

2018

Author

Batur, Ahmet

Metadata

Show full item record

Item Usage Stats

186
views

74
downloads

The Controller Area Network (CAN) is the most widely-used in-vehicle communication bus in the automotive industry. CAN enables the exchange of data among different electronic control units (ECUs) of a vehicle via messages. The basic requirement for the design of CAN is to guarantee that the worst-case response time (WCRT) of each message is smaller than its specified deadline. Hereby, it is generally desired to achieve small WCRTs that leave sufficient slack to the message deadline. In addition, it has to be noted that it might be very unlikely that a message experiences the WCRT when being transmitted on CAN. That is, instead of only considering the message WCRT for the design of CAN, it is beneficial to determine the actual response-time distribution of each message, which indicates the probability of experiencing a certain response time. In order to achieve small WCRTs, the idea of offset scheduling has been introduced. In this setting, messages on CAN are released with offsets in order to avoid message bursts that lead to undesirably large response times. In order to use offset scheduling efficiently, it is required to assign a suitable offset to each message. To this end, a load distribution (LD) algorithm is proposed in the existing literature. The first contribution of this thesis is the development of new algorithms for the offset assignment on CAN. Evaluating different example scenarios, the thesis shows that the proposed algorithms outperform the existing LD algorithm in most of the cases. As the second contribution, the thesis studies the computation of response time distributions. First, an algorithm for determining the exact response-time distribution of each message on CAN is proposed. Since this algorithm comes with a high computational complexity, it cannot be applied if there are too many messages on a CAN bus. Moreover, experimental results show that the response time distribution depends mostly on the initial phasing of the nodes. Therefore exact response time distribution as computed is not observed in the measurements. In response to this observation, the thesis proposes the computation of a local response time distribution and develops and implements a weak synchronization method which bounds the phase shift between the nodes. The resulting computed local response time distribution shows a very tight match with measured response time distributions.

Subject Keywords

Controller Area Network (Computer network)., Algorithms.

URI

http://etd.lib.metu.edu.tr/upload/12621891/index.pdf
https://hdl.handle.net/11511/27104

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Development of strategies for reducing the worst-case message response times on the Controller Area Network Çelik, Vakkas; Schmidt, Şenan Ece; Schmidt, Klaus Verner; Department of Electrical and Electronics Engineering (2012) The controller area network (CAN) is the de-facto standard for in-vehicle communication. The growth of time-critical applications in modern cars leads to a considerable increase in the message tra c on CAN. Hence, it is essential to determine e cient message schedules on CAN that guarantee that all communicated messages meet their timing constraints. The aim of this thesis is to develop o set scheduling strategies that ﬁnd feasible schedules for higher bus load levels compared to conventional CAN scheduling...
A Frame packing method to improve the schedulability on CAN and CAN-FD / Urul, Gökhan; Schmidt, Şenan Ece; Schmidt, Klaus Verner; Department of Electrical and Electronics Engineering (2015) Controller Area Network (CAN) is the most widely used in-vehicle network. Today, vehicle applications can fill a CAN network's communication bandwidth to its limit. Hereby, the consumed bandwidth of an in-vehicle application depends on the efficiency of packing signal data into CAN message frames and on the suitability of the CAN message priority assignment such that all messages are schedulable. This thesis focuses on the problem of signal packing which is known to be and NP-hard problem. To this end, the ...
Controller area network response time analysis and scheduling for advanced topics: offsets, FIFO queues and gateways / Alkan, Burak; Schmidt, Şenan Ece; Schmidt, Klaus Verner; Department of Electrical and Electronics Engineering (2015) Controller Area Network (CAN) is the most widely used in-vehicle network for the communication among electronic control units (ECUs). CAN has a priority-based arbitration mechanism and the classical usage of CAN assumes the implementation of priority queues (PQs) on ECUs. Based on this assumption, the literature provides e cient algorithms for the computation of worst-case response times (WCRTs) of messages as well as for the appropriate assignment of priorities to messages in order to meet real-time guaran...
C³: configurable CAN FD controller: design, implementation and evaluation Afşin, Mehmet Ertuğ; Schmidt, Şenan Ece; Schmidt, Klaus Werner; Department of Electrical and Electronics Engineering (2018) CAN FD (Controller Area Network with Flexible Data Rate) is a new communication standard, compatible with CAN. Different from CAN, CAN FD switches to high data rate during data transmission and allows payloads up to 64 bytes. In this thesis, we propose C3: Configurable CAN FD Controller which features up to fully configurable 96 TX and 96 RX buffers organized as mailboxes. Each RX buffer has dedicated acceptance filters. The host MCU sees C3 as a memory mapped device and interfaces with it via SPI protocol ...
Clock synchronization and weak TDMA for CAN FD: Implementation and evaluation Demirel, İsmet Onur; Schmidt, Şenan Ece; Schmidt, Klaus Verner; Department of Electrical and Electronics Engineering (2022-12-27) The Controller Area Network (CAN) is the most widespread in-vehicle communication protocol. Although CAN has been used for many decades, there are very recent software-based enhancements that enable accurate clock synchronization and time-slotted medium access on CAN, denoted as weak time division multiple access (WTDMA), for deterministic bus access. In addition, there are recent updates to the CAN hardware such as CAN with flexible data rate (CAN FD) in order to both increase the available bit rate and th...

Citation Formats

A. Batur, “Controller area network with offset scheduling: improved offset assignment algorithms and computation of response time distributions,” M.S. - Master of Science, Middle East Technical University, 2018.