1,720,960 research outputs found
Communication networks for drive-by-wire applications
No full textThe automotive market is more and more interested in all-electric systems for the execution of the driving commands, i.e. in the so-called Drive-by-Wire (DbW) systems. The most crucial issue in their usage is the achievement of acceptable levels of dependability. From this point of view, the communication network of a DbW system is a critical component. Being the traditional fieldbuses used in the cars not suited to highly dependable applications, new communication networks have been devised, built up around protocols that accommodate powerful techniques to assure the dependability in the data exchange. This paper illustrates the characteristics of the communication networks for DbW systems, focusing on the techniques adopted to stand up against errors and faults of communicatio
Development and testing of a communication network for a drive-by-wire industrial vehicle
No full textDrive-by-wire (DbW) is an automotive technology aimed at substituting the traditional driving equipment with an all-electric system. In particular it utilizes a communication network to transmit the driving commands. This paper is focused on developing and testing a communication network for a DbW industrial vehicle. At first the safety requirements for the DbW system are established and its architecture is derived. Afterwards the specifications for the communication network are formulated. Two viable solutions for the network protocol are then evaluated and their communication performance is analyzed. At last an experimental network is set up and its behavior under data transmission is tested
Overcoming Babbling-Idiot Failures in CAN Networks: A Simple and Effective Bus Guardian Solution for the FlexCAN Architecture
No full textThis paper is concerned with the issue of protecting CAN networks against the consequences of babbling-idiot faults such as unscheduled traffic generated by a faulty node that denies any other communication. A full solution of the problem would greatly enhance the dependability of the CAN networks, making them applicable to safety-critical systems. After explaining the weakness of the native CAN protocol in tolerating the babbling-idiot faults, this paper shows how the FlexCAN architecture is suitable to tolerate them effectively. To this aim, a simple bus guardian is proposed and tested. The results of the test are given in this paper
Overcoming babbling-idiot failures in the FlexCAN architecture: a simple bus-guardian
No full textThe paper is concerned with the key issue of protecting FlexCAN networks against the babbling-idiot faults, e.g., node faults that busy the bus unduly. A full solution of the problem would enhance the dependability of these networks greatly, making them attractive for safety-critical applications. After analyzing the various modes by which a babbling-idiot fault affects the network operation, a classification of the babbling-idiot faults into hardware and software is proposed. Then it is shown that the FlexCAN architecture provides a suitable means for tolerating hardware babbling-idiot faults. Afterwards, a simple bus-guardian is proposed to cope with the software babbling-idiot faults in the FlexCAN environment. The proposed bus-guardian has been implemented and tested, and some significant results are given to demonstrate its effectivenes
Design of drive-by-wire communication network for an industrial vehicle
No full textDrive-by-wire (DbW) is an emerging technology in the automotive environment that provides for the transmission and actuation of the driving commands by means of electric devices. The commands are entered by appropriate transducers, forwarded to electrical drives via a communication network and applied to local mechanical actuators. This paper deals with a DbW system for an industrial vehicle, at first presenting the safety requirements for the vehicle and the system architecture arranged to meet the requirements. Then, the design of the communication network is presented. The variables to be conveyed are defined and the specifications for the data exchange are established. Two communication protocols are evaluated for possible implementation. An experimental rig implementing the selected protocol is described and the tasks devised to validate the design of the communication network are illustrate
CAN upgrade toward determinism and composability
No full textThe paper presents two solutions aimed at making the CAN networks deterministic and composable. The two solutions run on the application layer and exploit the services offered by either CANopen or the native CAN protocol. In the first solution, named Multimaster, each node operates as a master and the transmission cycle is initiated by a synchronization message. In the second solution, named SynCAN, each node transmits only in a fixed slot of time and in a sequence established a priori. The efficiency of the two solutions is analyzed and experimental data on the first solution are give
Dependability of safety-critical systems
No full textDependability, i.e. the capability of a system of delivering the expected service, is a fundamental requirement for safety-critical applications. It is becoming a very important matter in the automotive field. Indeed, car industries are planning to replace the traditional mechanical-hydraulic apparatus used for the execution of the driving commands with all-electric systems, the so-called drive-by-wire (DbW) systems, which are made of components that are not as reliable as the ones of the traditional apparatus. This paper, starting from the existing literature, provides at first a conceptual framework for the dependability topic. Then dependable architectures for DbW systems are presented. As a case of study, the steering maneuver is considered
Drive-by-wire systems for ground vehicles
No full textA significant innovation effort in ground vehicles' technology is represented by the replacement of the traditional mechanical-hydraulic systems with all-electric systems, termed by-wire systems, for the transmission and execution of the driving commands. According to the experience in the aerospace environment, such replacement is expected to give appreciable benefits, even though it poses several problems. This paper provides an overview of the key components of by-wire systems, i.e. the electric actuators and the communication networks, especially for steering and braking operation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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