Centralized vs distributed communication scheme on switched ethernet for embedded military applications

Current military communication network is a generation old and is no longer effective in meeting the emerging requirements imposed by the future embedded military applications. Therefore, a new interconnection system is needed to overcome these limitations. Two new communication networks based upon Full Duplex Switched Ethernet are presented herein in this aim. The first one uses a distributed communication scheme where equipments can emit their data simultaneously, which clearly improves system’s throughput and flexibility. However, migrating all existing applications into a compliant form could be an expensive step. To avoid this process, the second proposal consists in keeping the current centralized communication scheme. Our objective is to assess and compare the real time guarantees that each proposal can offer. The paper includes the functional description of each proposed communication network and a military avionic application to highlight proposals ability to support the required time constrained communications

Performance analysis of a Master/Slave switched Ethernet for military embedded applications

Current military communication network is a generation old and is no longer effective in meeting the emerging requirements imposed by the next generation military embedded applications. A new communication network based upon Full Duplex Switched Ethernet is proposed in this paper to overcome these limitations. To allow existing military subsystems to be easily supported by a Switched Ethernet network, our proposal consists in keeping their current centralized communication scheme by using an optimized master/slave transmission control on Switched Ethernet thanks to the Flexible Time Triggered (FTT) paradigm. Our main objective is to assess the performance of such a proposal and estimate the quality of service we can expect in terms of latency. Using the Network Calculus formalism, schedulability analysis are determined. These analysis are illustrated in the case of a realistic military embedded application extracted from a real military aircraft network, to highlight the proposal's ability to support the required time constrained communications

Development of functional safety applications for Autec products. Study of protocols: CANopen, CANopen Safety, FSOE and ProfiSafe

This thesis has the principal goal of developing intrinsic safety applications in distributed real-time industrial systems, mainly based on fieldbuses and RTE networks. To achieve this important objective the first part of this elaborate provides an introduction of the principal protocols, such as CANopen Safety, Fail safe Over Ethercat (FSOE) and Profisafe, used for the safety relevant applications in the automation environment,analysing properties,story and the use of them by industry

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

Hardware Acceleration for Conditional State-Based Communication Scheduling on Real-Time Ethernet

Distributed real-time applications implement distributed applications with timeliness requirements. Such systems require a deterministic communication medium with bounded communication delays. Ethernet is a widely used commodity network with many appliances and network components and represents a natural fit for real-time application; unfortunately, standard Ethernet provides no bounded communication delays. Conditional state-based communication schedules provide expressive means for specifying and executing with choice points, while staying verifiable. Such schedules implement an arbitration scheme and provide the developer with means to fit the arbitration scheme to the application demands instead of requiring the developer to tweak the application to fit a predefined scheme. An evaluation of this approach as software prototypes showed that jitter and execution overhead may diminish the gains. This work successfully addresses this problem with a synthesized soft processor. We present results around the development of the soft processor, the design choices, and the measurements on throughput and robustness

JAUS to EtherCAT Bridge: Toward Real-Time and Deterministic Joint Architecture for Unmanned Systems

The Joint Architecture for Unmanned Systems (JAUS) is a communication standard that allows for interoperability between Unmanned Vehicles (UVs). Current research indicates that JAUS-compliant systems do not meet real-time performance guidelines necessary for internal systems in UVs. However, there is a lack of quantitative data illustrating the performance shortcomings of JAUS or clear explanations on what causes these performance issues or comparisons with existing internal communication systems. In this research, we first develop a basic C++ implementation of JAUS and evaluate its performance with quantitative data and compare the results with published performance data of Controller Area Network (CAN) to determine the feasibility of the JAUS standard. Our results indicate that the main reason of JAUS’s poor performance lies in the latency inherent in the hierarchical structure of JAUS and the overhead of User Datagram Protocol (UDP) messages, which has been used with JAUS and is slower than the high-speed CAN. Additionally, UDP has no scheduling mechanism, which makes it virtually impossible to guarantee messages meeting their deadlines. Considering the slow and nondeterministic JAUS communication from subsystems to components, which is JAUS Level 3 compliance, we then propose a solution by bringing Ethernet for Control Automation Technology (EtherCAT) to add speed, deterministic feature, and security. The JAUS-EtherCAT mapping, which we called a JEBridge, is implemented into nodes and components. Both quantitative and qualitative results are provided to show that JEBridge and JAUS Level 3 compliance can bring not only interoperability but also reasonable performance to UVs

A Scalable, High-Performance, Real-Time Control Architecture with Application to Semi-Autonomous Teleoperation

A scalable and real-time capable infrastructure is required to enable high-performance control and haptic rendering of systems with many degrees-of-freedom. The specific platform that motivates this thesis work is the open research platform da Vinci ReResearch Kit (dVRK). For the system architecture, we propose a specialized IEEE-1394 (FireWire) broadcast protocol that takes advantage of broadcast and peer-to-peer transfers to minimize the number of transactions, and thus the software overhead, on the control PC, thereby enabling fast real-time control. It has also been extended to Ethernet via a novel Ethernet-to-FireWire bridge protocol. The software architecture consists of a distributed hardware interface layer, a real-time component-based software framework, and integration with the Robot Operating System (ROS). The architecture is scalable to support multiple active manipulators, reconfigurable to enable researchers to partition a full system into multiple independent subsystems, and extensible at all levels of control. This architecture has been applied to two semi-autonomous teleoperation applications. The first application is a suturing task in Robotic Minimally Invasive Surgery (RMIS), that includes the development of virtual fixtures for the needle passing and knot tying sub-tasks, with a multi-user study to verify their effectiveness. The second application concerns time-delayed teleoperation of a robotic arm for satellite servicing. The research contribution includes the development of a line virtual fixture with augmented reality, a test for different time delay configurations and a multi-user study that evaluates the effectiveness of the system