Simulation of Mixed Critical In-vehicular Networks

Future automotive applications ranging from advanced driver assistance to autonomous driving will largely increase demands on in-vehicular networks. Data flows of high bandwidth or low latency requirements, but in particular many additional communication relations will introduce a new level of complexity to the in-car communication system. It is expected that future communication backbones which interconnect sensors and actuators with ECU in cars will be built on Ethernet technologies. However, signalling from different application domains demands for network services of tailored attributes, including real-time transmission protocols as defined in the TSN Ethernet extensions. These QoS constraints will increase network complexity even further. Event-based simulation is a key technology to master the challenges of an in-car network design. This chapter introduces the domain-specific aspects and simulation models for in-vehicular networks and presents an overview of the car-centric network design process. Starting from a domain specific description language, we cover the corresponding simulation models with their workflows and apply our approach to a related case study for an in-car network of a premium car

Analysis of time delays in scheduled and unscheduled communication used in process automation

This paper introduces a network model for analysing the time delays of scheduled and unscheduled communication services among field devices used in process automation. The proposed model is implemented by configuring multiple control loops of real-time field devices into a network. The consensus of the network is designed using segment checkerTM simulation software. The simulated network of the field devices is re-configured for the proposed network model by mapping virtually. Every device is treated as a node in the network model and the real-time data is accessed. The time delays recorded for both scheduled and unscheduled communication of field-bus topology in simulation environment and the performance is compared with scheduled communication delay. The better bandwidth utilization and assignment of field device is achieved by introducing the unscheduled communication time delays in the network. It helps in the improvement of network capacity by accommodating more devices and reduces the commissioning cost

Flexible time-triggered protocol for CAN: new scheduling and dispatching solutions

One of the possibilities to build robust communication systems with respect to their temporal behaviour is to use autonomous control based on the time-triggered paradigm. The FTT-CAN - flexible time-triggered protocol, relies on centralised scheduling but makes use of the CAN native distributed arbitration to reduce communication overhead. There, a planning scheduler is used within a master node to reduce the scheduling run-time overhead. On-line changes to the communication requirements can then be made under guaranteed timeliness. In addition FTT-CAN also allows an efficient combination of both time-triggered and event- triggered traffic with temporal isolation. In this paper, recent evolutions of the initial protocol definition concerning transmission of synchronous and asynchronous messages are presented. These consist in a time division of the elementary transmission window which optimises the available bandwidth for asynchronous messages, keeping the timeliness of synchronous messages without jeopardising their transmission jitter. A novel solution for the planning scheduler is also presented. It consists in an FPGA-based coprocessor which implements the planning scheduler technique without imposing overhead to the arbiter CPU. With it, it is possible to reduce strongly the plan duration thus allowing on-line admission demanded by system elements and, also, to extend the protocol application to high-speed networks

Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks

CSP channels for CAN-bus connected embedded control systems

Closed loop control system typically contains multitude of sensors and actuators operated simultaneously. So they are parallel and distributed in its essence. But when mapping this parallelism to software, lot of obstacles concerning multithreading communication and synchronization issues arise. To overcome this problem, the CT kernel/library based on CSP algebra has been developed. This project (TES.5410) is about developing communication extension to the CT library to make it applicable in distributed systems. Since the library is tailored for control systems, properties and requirements of control systems are taken into special consideration. Applicability of existing middleware solutions is examined. A comparison of applicable fieldbus protocols is done in order to determine most suitable ones and CAN fieldbus is chosen to be first fieldbus used. Brief overview of CSP and existing CSP based libraries is given. Middleware architecture is proposed along with few novel ideas

FTT-Ethernet: A Flexible Real-Time Communication Protocol that Supports Dynamic QoS Management on Ethernet-based Systems

Ethernet was not originally developed to meet the requirements of real-time industrial automation systems and it was commonly considered unsuited for applications at the field level. Hence, several techniques were developed to make this protocol exhibit real-time behavior, some of them requiring specialized hardware, others providing soft-real-time guarantees only, or others achieving hard real-time guarantees with different levels of bandwidth efficiency. More recently, there has been an effort to support quality-of-service (QoS) negotiation and enforcement but there is not yet an Ethernet-based data link protocol capable of providing dynamic QoS management to further exploit the variable requirements of dynamic applications. This paper presents the FTT-Ethernet protocol, which efficiently supports hard-real-time operation in a flexible way, seamlessly over shared or switched Ethernet. The FTT-Ethernet protocol employs an efficient master/multislave transmission control technique and combines online scheduling with online admission control, to guarantee continued real-time operation under dynamic communication requirements, together with data structures and mechanisms that are tailored to support dynamic QoS management. The paper includes a sample application, aiming at the management of video streams, which highlights the protocol’s ability to support dynamic QoS management with real-time guarantees