FlexRay Bus Research Articles

On-board Application of FlexRay Bus

On-board Application of FlexRay Bus

Research on Distributed Measurement and Control System Based on FlexRay Bus

With the purpose of the design problem of electromagnetic launch distributed measurement and control system, this paper proposes a design method of scalable large-scale distributed interconnected measurement and control system based on FlexRay bus. The task execution time deviation of each node in the distributed system, including phase deviation and frequency deviation, is reduced by using the macro tick generation process and clock synchronization process to achieve task synchronization in the distributed system. The synchronization of timing generation is realized based on the universal clock technology. When the timing interval is zero, the pulse power units are guaranteed to be close to the ideal full synchronization, thus ensuring that the released energy during transmission is close to the design value. In the state of adjustable timing, when the pulse power supply module conducts pulse discharge, the trigger discharge times of the modules are set according to the load needs. The flat top, sawtooth, and other characteristic current waveforms are adjusted accurately. At the same time, a combined multi-level protection structure based on hardware and software is realized. The verification results show that the distributed electromagnetic launch measurement and control system implemented in this paper can meet the high efficiency, fast and continuous launch target.

Research of Security and Reliability for In-Vehicle FlexRay Bus Network Based on Message Perception Method

Research of Security and Reliability for In-Vehicle FlexRay Bus Network Based on Message Perception Method

Research on Teaching Reform of the Course "Vehicle Network and Information System Maintenance" Based on CAN FLEXRAY Bus Networking Technology

Research on Teaching Reform of the Course "Vehicle Network and Information System Maintenance" Based on CAN FLEXRAY Bus Networking Technology

A Security Framework for In-Vehicle FlexRay Bus Network

With the continuous development of automotive electronic technology and the maturity of system integration technology, the real-time performance and security have attracted more and more attention in automotive industries. However, identically with other in-vehicle bus protocol (e.g. CAN, LIN and MOST), their security are not considered in the origin of design. Therefore, security of FlexRay bus is directly related to human's privacy and life. In this paper, we proposed a security framework for FlexRay network. Considering the limitation of computing resources and the real-time performance of in-vehicle ECUs, we optimize the original MAC(Message Authentication) algorithm. To strength the security level and robutness of the system, we recommend to use ECC (Elliptic Curves Cryptography) encryption algorithm and dual channel model for our security framework. By using our proposed model, the bandwidth can be reduced 25% and the computational time can decrease evidently.

A way to synchronize clocks with the FlexRay bus

In order to ensure that different systems work together under the same clock, it is necessary to propose a unified time management system and a unified time benchmark, this paper studies the method of clock synchronization based on FlexRay bus, which has been verified by the laboratory to achieve clock synchronization by FlexRay bus, with synchronization accuracy of less than 10us.

Tool Integration for Automated Synthesis of Distributed Embedded Controllers

Controller design and their software implementations are usually done in isolated design spaces using respective COTS design tools. However, this separation of concerns can lead to long debugging and integration phases. This is because assumptions made about the implementation platform during the design phase—e.g., related to timing—might not hold in practice, thereby leading to unacceptable control performance. In order to address this, several control/architecture co-design techniques have been proposed in the literature. However, their adoption in practice has been hampered by the lack of design flows using commercial tools. To the best of our knowledge, this is the first article that implements such a co-design method using commercially available design tools in an automotive setting, with the aim of minimally disrupting existing design flows practiced in the industry. The goal of such co-design is to jointly determine controller and platform parameters in order to avoid any design-implementation gap , thereby minimizing implementation time testing and debugging. Our setting involves distributed implementations of control algorithms on automotive electronic control units ( ECUs ) communicating via a FlexRay bus. The co-design and the associated toolchain Co-Flex jointly determines controller and FlexRay parameters (that impact signal delays) in order to optimize specified design metrics. Co-Flex seamlessly integrates the modeling and analysis of control systems in MATLAB/Simulink with platform modeling and configuration in SIMTOOLS/SIMTARGET that is used for configuring FlexRay bus parameters. It automates the generation of multiple Pareto-optimal design options with respect to the quality of control and the resource usage, that an engineer can choose from. In this article, we outline a step-by-step software development process based on Co-Flex tools for distributed control applications. While our exposition is automotive specific, this design flow can easily be extended to other domains.

FlexRay bus data fault diagnosis based on Zynq

CAN bus and LIN bus are widely used as communication bus in automobile industry.As a new type of automobile bus, FlexRay bus, with CAN bus and LIN bus do not have many advantages. FlexRay bus bandwidth is not limited by protocol mechanisms,and it use the synchronization-based access methods. And because of its unique dual-channel data transfer mode, which is especially suitable for the current automotive wire control system, it replaces the mechanical and hydraulic working mode of traditional automobile. And the FlexRay data transmission rate is fast, it can quickly transmit data to the car’s electronic control unit. Zynq as an extensible platform combining ARM and FPGA,satisfying the programmability of the software,it also meets the programmability of hardware. Zynq chip functions can be divided into two working parts, A PS,another is PL. PS is the ARM part, mainly responsible for data storage and display module control and other functions; PL is the FPGA part, the main functions are data acquisition processing and time unification. Using based on Zynq data diagnosis FlexRay vehicle bus, can make data transmission more reliable and efficient, It can also effectively reduce the power consumption of the whole system.

Optimal Fuzzy PID Controller Design for Stability of FlexRay Bus in NCS

Optimal Fuzzy PID Controller Design for Stability of FlexRay Bus in NCS

An efficient formulation for optimization of FlexRay frame scheduling

FlexRay is a communication bus for automotive applications, designed to ensure high data rates, fault tolerance, and operates on a time cycle, split in static and dynamic segments for event-triggered and time-triggered communications. Therefore, it becomes suitable for hard real-time and safety-critical applications. Furthermore, it enables cyclic and acyclic communication in the static and dynamic segments according to their specifications, ensuring synchronized, error-free communication between transmitters and receivers. One challenge for applying this protocol, however, is the complexity of the task of message scheduling, for which some techniques have already been developed and we explored to show our method. Here, we carried out the analysis for a specific application that deploys the FlexRay bus, through a heuristic method with the support of a computer software to search for the best combination of message scheduling of the entire system. The effectiveness of the proposed approach is demonstrated by a case study performed within the automotive domain.

Research on Flex Ray Bus Technology In Vehicle Electronic System

In order to ensure the driving safety of the car, the on-board electronic system is studied based on Flex Ray bus technology. Firstly, the structure of Flex Ray vehicle electronic system is optimized according to the operation requirements of vehicle electronic system, and Flex Ray application protocol is set up to complete the control and management of vehicle electronic system according to the settings of Flex Ray application protocol. Finally, the experiment proves that the application effect of Flex Ray bus technology in vehicle electronic system is obviously improved compared with the traditional method.

LM Algorithm Neural Network Predictive Control of FlexRay Bus System

In view of the uncertainty of data transmission due to the irregular data flow in the network and the limitation of network bandwidth resources, which makes the control performance and stability of FlexRay network decrease when data is transmitted at high speed and the reliability and safety of the control system can not be guaranteed, this paper proposes a method based on the Levenberg-Marquardt (LM) algorithm for neural network predictive control of the FlexRay bus. The method can predict the next moment operating state of the car network according to the current moment working state of the FlexRay car network to adaptively adjust task workload to adapt to changes in vehicle network system load and improve the reliability and stability of FlexRay network control system. The simulation results show that the neural network predictive control has good adaptability and robustness, which improves the control performance of the FlexRay automotive networked control system effectively.

Timing Analysis of Precedence Constraint Messages Scheduled With Slot Multiplexing Over Dynamic Segment of FlexRay

FlexRay offers high-speed reliable transmission in the vehicle domain. Thus, it is one of the most popular in-vehicle communication protocols for the applications that are safety-critical or applications with very low transmission time requirement. Due to the real-time constraint, the worst case end-to-end delay (EED) for such applications transmitting over a shared bus must be known. This paper addresses the problem of computation of EED for a given set of tasks with precedence constraint and corresponding messages, which are scheduled with slot multiplexing for event-triggered communication over the dynamic segment of FlexRay. First, computing precise delay has been shown to be an intractable problem. Subsequently, motivated by the intractability, an efficient estimation technique has been proposed to compute approximate EED. Unlike the common practice of considering the network in isolation, we present a comprehensive timing analysis, which considers the effects of task execution as well. Moreover, EED is allowed to be greater than interactivation time of task graph. The extensive simulation has been performed on the test cases generated with uniform as well as normal distribution. Note to Practitioners —In the past few decades, due to the large-scale use and sophistication of automotive electronic systems, various in-vehicle communication networks and protocols are also evolving. FlexRay is one such in-vehicle communication protocol, which provides the mechanism for the fault-tolerant high-speed communication over FlexRay bus. FlexRay is widely being employed for safety-critical applications in the automotive domain. For such applications, often the timing constraint is imposed with a bound on the worst case EED. Thus, timing properties of the designed network must be verified before applying it on the real domain such that the worst case EED for the propagation of an event at sensor end to actuator end is known. The proposed estimation technique can be used to compute approximate EED for an application scheduled with other applications over the dynamic segment of FlexRay. In addition, various guidelines for designing the network in order to reduce overestimation have also been presented.

Hardware-in-loop real-time simulation of electrical vehicle using multi-simulation platform based on data fusion approach

A hardware-in-loop real-time multi-simulation platform system is established based on data fusion approach, and the vehicle closed-loop control system is obtained based on “driver–central controller–motor drive system–vehicle dynamics,” on which the control strategy of wheel-motor-driven multi-axle vehicle is verified. Data among the platform are transformed based on FlexRay bus. A simulation experiment of electrical vehicle dynamic performance is tested by real driver in real time to analyze whether vehicle dynamic performance is performed based on the multi-platform. The results indicate that the hardware-in-loop real-time simulation system can effectively verify the reliability of control strategy, and the data fusion of multi-simulation-platform works well.

Efficient lossless compression for depth information in traffic scenarios

Modern day automotive features (e.g., in-vehicle augmented reality) require a depth of the environment as the input source. It is important that depth data can be transferred from one processing unit to another in a car. About 10 years ago, Stixel has been introduced as a mid-level representation of depth maps (disparities) which reduces the data volume thereof significantly. Since then, Stixel has been extensively researched and is nowadays a seriously considered solution for series production cars. Nevertheless, even after using a Stixel representation, the depth data can hardly fit into a low- or medium-bandwidth in-vehicle communication system, e.g., via a CAN bus. Hence, the cost-sensitive automotive industry is still seeking new solutions for the transmission of depth information using in-vehicle communication buses. In this paper, we present an efficient lossless compression scheme for Stixels as a potential solution to this problem. Our proposed algorithm removes both spatial and temporal redundancies in Stixels through a combination of predictive modeling and entropy coding. Evaluation shows that it outperforms general purpose compression schemes, e.g., zlib, by more than $$60\%$$ in space savings. More importantly, we prove that using the proposed Stixel compression, depth information could be transmitted through a less expensive CAN bus, whereas a much more expensive FlexRay bus is needed otherwise. We believe that this finding has great relevance for the automotive industry.

Концепция стенда для исследования кибербезопасности устройств на шине FlexRay «подключенного» транспортного средства, основанная на использовании интерфейсных плат

The article proposes the concept of a stand for researching the vulnerabilities of devices onthe FlexRay bus, the so-called “Connected” vehicle , the operation of which uses digital datatransmission systems. The main problems of cybersecurity of such objects are related to the possibility of compromising the data exchanged between the vehicle devices during its operation.The relevance of the study of cybersecurity of such devices is associated with the need to ensuretraffic safety. To simulate the effects on the bus, in particular, the substitution and injection ofsignals by intruders, it is proposed to use interface cards designed to study the FlexRay bus, programmed in the Labview development environment.

DDS middleware on top of FlexRay networks: Simulink blockset implementation of electrical vehicle using FlexRay protocol and its adaptation to DDS concept

We designed a Simulink vehicle blockset in order to integrate safety, reliability, best condition of luxury and comfort in modern models by adding or modifying some old algorithms, implemented as application layer components. The proposed blockset corresponds to the Society of Automotive Engineers benchmark which is normally connected by the CAN bus that we replaced by the FlexRay bus. We used the Embedded MATLAB tool for implementing this blockset in order to generate a portable C standard code. To connect the designed sub-blocks together, we applied the real-time middleware data distribution service (DDS) and the FlexRay protocol. In this paper, we focused our interest on the implementation of the Simulink blockset with its different sub-blocks and we then identified their DDS entities and their QoS profiles. We also calculated the worst-case response time, based on the full scheduling model, which served to configure the DDS deadline QoS and the FlexRay protocol parameters.

Design Scheme of Communication Node Based on FlexRay Bus

As a high-speed and reliable serial communication bus, the FlexRay bus has gradually become the mainstream of vehicle network systems. In order to verify the feasibility of the bus technology in aerospace applications, this paper designs a FlexRay communication node based on TI's high-performance microcontroller TMS570LS3137 for security systems. In the whole system, with the DSP of core, the FlexRay communication protocol is achieved by using the bus controller TJA1080 to carry out data transmission. This method is suitable for data transmission of pint and medium-sized UAV (unmanned air vehicles) flight control system with high integration and high transmission rate.

Using Two Independent Channels With Gateway for FlexRay Static Segment Scheduling

The FlexRay bus is a communication standard used in the automotive industry. It offers a deterministic message transmission in the static segment following a time-triggered schedule. Even if its bandwidth is ten times higher than the bandwidth of CAN, its throughput limits are going to be reached in high-class car models soon. A solution that could postpone this problem is to use an efficient scheduling algorithm that exploits both channels of the FlexRay. The significant and often neglected feature that can theoretically double the bandwidth is the possibility to use two independent communication channels that can intercommunicate through the gateway. In this paper, we propose a heuristic algorithm that decomposes the scheduling problem to the ECU-to-channel assignment subproblem which decides which channel the ECUs (Electronic Control Units) should be connected to and the channel scheduling subproblem which creates static segment communication schedules for both channels. The algorithm is able to create a schedule for cases where channels are configured in the independent mode as well as in the fault-tolerant mode or in cases where just part of the signals are fault-tolerant. Finally, the algorithm is evaluated on real data and synthesized data, and the relation between the portion of fault-tolerant signals and the number of allocated slots is presented.

Design on Electric Vehicle Battery Management System with FlexRay Bus

FlexRay bus is considered as a more promising bus in the future with the performance of real-time, scalable, and fault-tolerant. In this paper we will design an electric vehicle battery management system (BMS) based on FlexRay bus, including the hardware design, the SoC estimation method, FlexRay protocol design and software development. The test bench experiment results show the system design is reasonable and feasible.Keywords- FlexRay, BMS, Li-ion battery,SoC, Design