Françoise Simonot-Lion

Trends in Automotive Communication Systems

The use of networks for communications between the electronic control units (ECU) of a vehicle in production cars dates from the beginning of the 1990s. The specific requirements of the different car domains have led to the development of a large number of automotive networks such as Local Interconnect Network, J1850, CAN, TTP/C, FlexRay, media-oriented system transport, IDB1394, etc. This paper first introduces the context of in-vehicle embedded systems and, in particular, the requirements imposed on the communication systems. Then, a comprehensive review of the most widely used automotive networks, as well as the emerging ones, is given. Next, the current efforts of the automotive industry on middleware technologies, which may be of great help in mastering the heterogeneity, are reviewed. Finally, we highlight future trends in the development of automotive communication systems.

Multisource Software on Multicore Automotive ECUs—Combining Runnable Sequencing With Task Scheduling

As the demand for computing power is quickly increasing in the automotive domain, car manufacturers and tier-one suppliers are gradually introducing multicore electronic control units (ECUs) in their electronic architectures. In addition, these multicore ECUs offer new features such as higher levels of parallelism, which ease the compliance with safety requirements such as the International Organization for Standardization (ISO) 26262 and the implementation of other automotive use cases. These new features involve greater complexity in the design, development, and verification of the software applications. Hence, car manufacturers and suppliers will require new tools and methodologies for deployment and validation. In this paper, we address the problem of sequencing numerous elementary software modules, called runnables, on a limited set of identical cores. We show how this problem can be addressed as the following two subproblems, which cannot optimally be solved due to their algorithmic complexity: 1) partitioning the set of runnables and 2) building the sequencing of the runnables on each core. We then present low-complexity heuristics to partition and build sequencer tasks that execute the runnable set on each core. Finally, we globally address the scheduling problem, at the ECU level, by discussing how we can extend this approach in cases where other OS tasks are scheduled on the same cores as the sequencer tasks.

EAST-ADL — An Architecture Description Language

The part of embedded electronic systems in vehicles is nowadays growing. The European EAST-EEA project aims to bring efficient methods and tools for mastering the complexity of these systems. We present EAST-ADL, an Architecture Description Language developed in this project et show how the verification and validation activities are linked to this language.

Quantitative evaluation of the safety of X-by-Wire architecture subject to EMI perturbations

The X-by-Wire systems in cars can only be accepted if they provide at least the same dependability than the traditional ones. In this paper we propose a new approach to evaluate the impact of the EMI perturbations on the dependability of an X-by-Wire architecture. The considered X-by-Wire architecture is distributed around a TDMA-like communication protocol. So a perturbation causes the loss of a communication cycle with a certain probability. The vehicle level failure is then defined as the consecutive loss of a certain number of communication cycles. Its reliability is modeled as that of the well-known consecutive-k-out-of-n:F systems. A case study, together with the EMI perturbations collected on the roads in France, is used to illustrate our approach

Optimal on-line (m,k)-firm constraint assignment for real-time control tasks based on plant state information

In this paper, we study the problem of scheduling a set of control tasks. We distinguish three different situations of states of controlled plants: not activated, steady state situation and transient situation. The infinite-horizon and finite-horizon cost functions are respectively used to represent the performance of each control task in last two situations. We propose a scheduling architecture in which, according to the plant state situation, the task handler switches between these two types of performance criterion to determine an on-line (m,k)-constraint based control task scheduling strategy, so that the overall control performance is maintained at a high level in each situation subject to the task schedulability. The approach is exemplified on a set of controllers for different plants.

In car embedded electronic architectures: how to ensure their safety

Abstract The part of software based systems in a car is growing. Moreover, in the next years will emerge the X-by-Wire technology that intends to replace mechanical or hydraulic systems by electronic ones even for critical function as braking or steering. This requires a stringent proof that these new vehicles will ensure the safety of driver, occupants. vehicle and environment. In this paper. we intend to list certain activities and key points for ensuring the development of a safe and optimized embedded system. More precisely, we propose two main axis that contribute to establish a design methodology of such systems. The first one identifies the generic components of an embedded system while the second one details how to model and validate the embedded system throughout the different steps of the development process.

Equivalence of timed state machines and safe TPN

We show that an important subclass of timed automata (Alur and Dill, 1994), called timed state machines, is weakly time equivalent to safe non-zero time Petri nets (TPNs) in the sense of Merlin and Farber (1976). We present an explicit construction for two-way translation between 1-safe TPNs and TSMs. The translation improves on the efficiency of other methods: the TSM obtained for a given net is polynomial in the size of the reachability graph, and a given TSM is translated into a net whose size grows linearly with that of the automaton model.

AN ARCHITECTURE DESCRIPTION LANGUAGE FOR IN-VEHICLE EMBEDDED SYSTEM DEVELOPMENT

Abstract Abstract. This paper presents the AEE project (Embedded Electronic Architecture), a French cooperative research and development program whose purpose is to specify new solutions for in-vehicle embedded system development. The Architecture Implementation Language (AIL_Transport) has been defined to specify and describe precisely any vehicle electronic architecture. This language supports the AEE design process, and is used by all designers as the backbone of the architecture development. Finally it is used to define reusable architecture objects.

Dependable Distributed Computer Control Systems: Analysis of the Design Step Activities

Abstract The paper sets the problem of the design step in the context of production automated systems and presents a modeling of this activity. The design step is located after the specification one and before the strictly speaking implementation one. The problem is to be sure that the partitioning of the specified application into intercommunicating modules and the allocation of the modules to computing assets and communication systems will satisfy the different constraints expressed in the end-user requirements, and in the specification.

Frame packing under real-time constraints

The set of frames of an in-vehicle application must meet two constraints: it has to be feasible from a schedulability point of view and it should minimize the network bandwidth consumption. The latter point is crucial for enabling the use of low cost electronic components and for facilitating an incremental design process. This study proposes two heuristics for the NP-complete problem of generating a set of schedulable frames that minimizes the bandwidth usage. The proposed strategies are complementary. The first one can be applied to large sized problems (in the context of in-vehicle applications) while the second one, slightly more efficient in our experiments, is limited to small size problems (less than 12 signals emitted by each stations). These proposals has proved to be effective in comparison with other possible strategies.