Data Distribution Service (DDS) Community and Research Portal

ABSTRACT: Publish/subscribe (pub/sub) middleware platforms for event- based distributed systems often provide many configurable policies that affect end-to-end quality of service (QoS). Although the flexibility and functionality of pub/sub middle- ware platforms has matured, configuring their QoS policies in semantically compatible ways has become more complex.

This paper makes two contributions to reducing the complexity of configuring QoS policies for event-based distributed systems. First, it evaluates various approaches for managing complex QoS policy configurations in pub/sub middleware platforms. Second, it describes a domain-specific modeling language (DSML) that automates the analysis and synthesis of semantically compatible QoS policy configurations.

This robotic application leverages RTI Data-Distribution Service to integrate the different components in a robotic system, such as trajectory generation, control, archiving, OPC components, etc.

Abstract: Future production concepts which are currently developed in the scope of “agile production” will require autonomous working and transportation platforms which dispose of much higher flexibility and robustness than current autonomous guided vehicle (AGV). One the one hand, such flexibility and robustness will only be possible if an optimal functionality and interoperability of the monitoring, planning, control and diagnosis systems can be achieved. On the other hand, a rapid multidimensional trajectory planning is inevitable in order to achieve the required flexibility and robustness.

In the first part of this paper a hierarchical and distributed concept and realization proposal will be presented aiming at optimized functionality and interoperability. Based on the concept and the realization proposal, a system for multidimensional trajectory planning called “trajectory kernel” in a basic and an enhanced form will be presented in the second part. The paper concludes with an outlook to the control of multiple autonomous vehicles applying Max-plus-Algebra. It is important to note that the focus of this paper is not a description of the respective algorithms but an explanation of the framework and the application. Investigations about the industrial application of intelligent systems for monitoring, control and diagnosis (Kleinmann et al. 2009, Stetter & Kleinmann 2011) have shown that frequently not the lack of the optimum algorithms but the missing integration in existing infrastructure and a missing higher level concept are important causes for the low application ratio of such intelligent systems. Consequently, research aiming at optimized integration and searching for high level concepts is obviously as desirable as the search for new and improved algorithms.

Abstract—The use of simulation in training and education enables to prepare personal in realistic environment. But the cost and the complexity to create and reuse simulations often

limits their application. In this paper we investigate a low cost and high fidelity PC-based simulator based on Data Distribution Service (DDS) middleware. The main parts of the systems and

the architecture, including the hardware and the software are introduced. Real-time networking between distributed simulators is achieved using a reliable distributed communication, which

employs publish-subscribe middleware build using OMG-DDS. Result shows these methods could produce low cost, extensible, reliable and distributed simulators.

http://community.rti.com/sites/default/files/users/Hakiri/103.pdf

This paper describe a details of implementing for DDS to be publish data in CAN BUS

Abstract: The Publish/Subscribe paradigm matches well with these systems. Data Distribution Service (DDS) is a Publish/Subscribe data-centric middleware. It specifies an API designed for enabling real-time data distribution and is well suited for such complex distributed systems and QoS-enabled applications. Unfortunately, the need to transmit a large number of sensor measurements over a network negatively affects the timing parameters of the control loops. The CAN-bus enables the information from a large number of sensor measurements to be conveyed within a few messages. Its priority-based medium access control is used to select the sensor messages with high timing constraints. This approach greatly reduces the time for obtaining a snapshot of the environment state and therefore supports the real- time requirements of feedback control loops.

The use of the “ Publish/Subscribe/Distribute ” paradigm and the underlying real -time CAN-Bus is a currently research topic an d only today few works exist in this area. These activities are headed by University of ULM & German National Research Center for Information Technology and by Software Architecture Lab, Seoul National University as well as by our "Control and Communication Technologies" research group at the National School of Engineering of Tunis (ENIT), Department of Computer and Communication Technologies, headed by myself. The main objective of this paper is to demonstrate how DDS API is implemented on a CAN-Bus.

The OMG Data Distribution Service (DDS) is an emerging specification for publish-subscribe data distribution systems. The purpose of the specification is to provide a common application-level interface that clearly defines the data distribution service. The specification describes the service using UML, thus providing a platform-independent model that can then be mapped into a variety of concrete platforms and programming languages.

The OMG DDS attempts to unify the common practice of several existing implementations [2, 5] enumerating and providing formal definitions for the QoS (Quality of Service) settings that can be used to configure the service.

This paper introduces the OMG DDS specification, describes the main aspects of the model, QoS settings, and gives examples of the communication scenarios it supports.

Abstract: Recent trends in distributed real-time and embed- ded (DRE) systems motivate the development of infor- mation management capabilities that ensure the right information is delivered to the right place at the right time to satisfy quality of service (QoS) requirements in heterogeneous environments. A promising approach to building and evolving large-scale and long-lived DRE information management systems are standards-based QoS-enabled publish/subscribe (pub/sub) platforms that enable participants to communicate by publishing information they have and subscribing to information they need in a timely manner. Since there is little exist- ing evaluation of how well these platforms meet the performance needs of DRE information management, this paper provides two contributions: (1) it describes three common architectures for the OMG Data Distri- bution Service (DDS), which is a QoS-enabled pub/sub platform standard, and (2) it evaluates implementa- tions of these architectures to investigate their design tradeoffs and compare their performance with each other and with other pub/sub middleware. Our results show that DDS implementations perform significantly better than non-DDS alternatives and are well-suited for certain classes of data-critical DRE information management systems.

Abstract: This paper presents the communication network for machine vision system to implement to control systems and logistics applications in industrial environment. The real-time distributed over the network is very important for communication among vision node, image processing and control as well as the distributed I/O node. A robust implementation both with respect to camera packaging and data transmission has been accounted. This network consists of a gigabit Ethernet network and a switch with integrated fire-wall is used to distribute the data and provide connection to the imaging control station and IEC-61131 conform signal integration comprising the Modbus TCP protocol. The real-time and delay time properties each part on the network were considered and worked out in this paper.

Abstract: Many complex distributed real-time applications need complicated processing and sharing of an extensive amount of data under critical timing constraints. In this paper, we present a comprehensive overview of the Data Distribution Service standard (DDS) and describe its QoS features for developing real-time applications. An overview of an active real-time database (ARTDB) named Agilor is also provided. For efficient expressing QoS policy in Agilor, a Real-time ECA (RECA) rule model is presented based on common ECA rule. And then we propose a novel QoS-aware Real-Time Publish-Subscribe (QRTPS) service compatible to DDS for distributed real-time data acquisition. Furthermore, QRTPS is implemented on Agilor by using objects and RECA rules in Agilor. To illustrate the benefits of QRTPS for real-time data acquisition, an example application is presented.

Abstract: To realize real-time information sharing in generic platforms, it is especially important to support dynamic message structure changes. For the case of IDL, it is necessary to rewrite applications to change data sample structures. In this paper, we propose a dynamic reconfiguration scheme of data sample structures for DDS. Instead of using IDL, which is the static data sample structure model of DDS, we use a self describing model using data sample schema, as a dynamic data sample structure model to support dynamic reconfiguration of data sample structures. We also propose a data propagation model to provide data persistency in distributed environments. We guarantee persistency by transferring data samples through relay nodes to the receiving nodes, which have not participated in the data distribution network at the data sample distribution time. The proposed schemes can be utilized to support data sample structure changes during operation time and to provide data persistency in various environments, such as real-time enterprise environments and connection-less internet environments.