Asynchronous real-time ethernet

The Industrial Ethernet has become a way to build distributed systems in industrial networks which must provide predictable performance and maintainability. Industrial applications require time-critical processing, which can be guaranteed within soft or hard real-time environments, Where applications' responses require deterministic processing time, the hard real-time environment is requested. The Fieldbus protocols are the standard way to connect instruments on the Ethernet-based communication. Fieldbuses require synchronisation and dedicated application-specific integrated circuits, what leaves space for alternate, more common solutions. This thesis presents design, implementation, and evaluation of the novel Real-Time Driver Model asynchronous communication stack called 61850CS API. 61850CS stack is implemented in an intelligent electronic device to enable real-time IEC 61850 GOOSE Ethernet communications in electrical substations. The presented 61850CS implementation enables simultaneous flow of real-time and non-real-time Ethernet traffic over the same physical network interface controller. The same technology supports running arbitrary real-time Ethernet traffic and non real-time Ethernet traffic simultaneously and its implementation is general enough to enable an API use on different architectures and to comply with different industrial Ethernet requirements. And more, since 61850CS doesn't affect CSMA/CD mechanism, it doesn't need any master nodes, which increases the system availability. The presented solution was implemented as an application programming interface for feeder protection and control (FPC 680) intelligent electronic device relay. Hardware platform for 61850CS was PPC440EPx microcontroller with implemented Linux Real-Time application interface RTOS. The FPC 680 is an IED commercial product by Iskra d.d. which is implemented worldwide in several substations

Asynchronous real-time ethernet

The Industrial Ethernet has become a way to build distributed systems in industrial networks which must provide predictable performance and maintainability. Industrial applications require time-critical processing, which can be guaranteed within soft or hard real-time environments, Where applications' responses require deterministic processing time, the hard real-time environment is requested. The Fieldbus protocols are the standard way to connect instruments on the Ethernet-based communication. Fieldbuses require synchronisation and dedicated application-specific integrated circuits, what leaves space for alternate, more common solutions. This thesis presents design, implementation, and evaluation of the novel Real-Time Driver Model asynchronous communication stack called 61850CS API. 61850CS stack is implemented in an intelligent electronic device to enable real-time IEC 61850 GOOSE Ethernet communications in electrical substations. The presented 61850CS implementation enables simultaneous flow of real-time and non-real-time Ethernet traffic over the same physical network interface controller. The same technology supports running arbitrary real-time Ethernet traffic and non real-time Ethernet traffic simultaneously and its implementation is general enough to enable an API use on different architectures and to comply with different industrial Ethernet requirements. And more, since 61850CS doesn't affect CSMA/CD mechanism, it doesn't need any master nodes, which increases the system availability. The presented solution was implemented as an application programming interface for feeder protection and control (FPC 680) intelligent electronic device relay. Hardware platform for 61850CS was PPC440EPx microcontroller with implemented Linux Real-Time application interface RTOS. The FPC 680 is an IED commercial product by Iskra d.d. which is implemented worldwide in several substations

Flexible Composition of Robot Logic with Computer Vision Services

Vision-based robotics is an ever-growing field within industrial automation. Demands for greater flexibility and higher quality motivate manufacturing companies to adopt these technologies for such tasks as material handling, assembly, and inspection. In addition to the direct use in the manufacturing setting, robots combined with vision systems serve as highly flexible means for realization of prototyping test-beds in the R&D context.Traditionally, the problem areas of robotics and computer vision are attacked separately. An exception is the study of vision-based servo control, the focus of which constitutes control-theoretic aspects of vision-based robot guidance under assumption that robot joints can be controlled directly. The missing part is a systemic approach to implementing robotic application with vision sensing given industrial robots constrained by their programming interface. This thesis targets the development process of vision-based robotic systems in an event-driven environment. It focuses on design and composition of three functional components: (1) robot control function, (2) image acquisition function, and (3) image processing function. The thesis approaches its goal by a combination of laboratory results, a case study of an industrial company (Kongsberg Automotive AS), and formalization of computational abstractions and architectural solutions. The image processing function is tackled with the application of reactive pipelines. The proposed system development method allows for smooth transition from early-stage vision algorithm prototyping to the integration phase. The image acquisition function in this thesis is exposed in a service-oriented manner with the help of a flexible set of concurrent computational primitives. To realize control of industrial robots, a distributed architecture is devised, which supports composability of communication-heavy robot logic, as well as flexible coupling of the robot control node with vision services

Fast-Settling Two-Stage Automatic Gain Control for Multi-Service Fibre-Wireless Fronthaul Systems

© 2013 IEEE. With the development of fast digitiser and digital signal processing techniques, wide-band digital radio-over-fiber (DRoF) based wireless fronthaul systems have been extensively studied as a way of offering multi-service wireless coverage. With data compression, the high digital data rate caused by digitisation can be reduced so as to minimise the infrastructure cost for last-mile cellular coverage. However, data compression always comes with the cost of a lower input power dynamic range. To overcome the issue, this paper proposes a novel fast-settling two-stage automatic gain control (FSS-AGC) algorithm, in which gain adjustment is carried out by a multi-threshold decision mechanism with a fast-settling time (within 2 μs), high stability and great accuracy. By introducing a novel gain control mechanism which simultaneously adjusts the gain in the digital and RF domains, the loss of dynamic range after compression is compensated. This algorithm is applied and demonstrated in a DRoF based digital distributed antenna system (DDAS) which supports all current cellular services from 3 Chinese mobile network operators (MNOs). The demonstration shows over 73dB dynamic range, with 40dB improvement compared with conventional links. Its promising properties and excellent performance enable its potential application in next-generation converged networks for Internet of things (IoT) and 5G services.National Natural Science Foundation of China under Grant 61371006, the Equipment Advance Research Project, the Defense Industrial Technology Development Program, the Chinese Government Fund, the International Cooperative Project of Smart In-building Wireless System using Flexible Digital Transmission Technology (SWIFT

Control Effort Strategies for Acoustically Coupled Distributed Acoustic Nodes

[EN] This paper considers the effect of effort constraints on the behavior of an active noise control (ANC) system over a distributed network composed of acoustic nodes. A distributed implementation can be desirable in order to provide more flexible, versatile, and scalable ANC systems. In this regard, the distributed version of the multiple error filtered-x least mean square (DMEFxLMS) algorithm that allows collaboration between nodes has shown excellent properties. However, practical constraints need to be considered since, in real scenarios, the acoustic nodes are equipped with power constrained actuators. If these constraints are not considered within the adaptive algorithm, the control signals may increase and saturate the hardware devices, causing system instability. To avoid this drawback, a control effort weighting can be considered in the cost function of the distributed algorithm at each node. Therefore, a control effort strategy over the output signals at each node is used to keep them under a given threshold and ensuring the distributed ANC system stability. Experimental results show that, assuming ideal network communications, the proposed distributed algorithm achieves the same performance as the leaky centralized ANC system. A performance evaluation of several versions of the leaky DMEFxLMS algorithm in realistic scenarios is also included.This work has been supported by European Union ERDF together with Spanish Government through TEC2015-67387-C4-1-R project and Generalitat Valenciana through PROMETEOII/2014/003 project.Antoñanzas-Manuel, C.; Ferrer Contreras, M.; Diego Antón, MD.; Gonzalez, A. (2017). Control Effort Strategies for Acoustically Coupled Distributed Acoustic Nodes. Wireless Communications and Mobile Computing. 2017:1-15. https://doi.org/10.1155/2017/3601802S1152017Akyildiz, I. F., Weilian Su, Sankarasubramaniam, Y., & Cayirci, E. (2002). 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J., Cobos, M., & Navarro, J. M. (2015). Low-Cost Alternatives for Urban Noise Nuisance Monitoring Using Wireless Sensor Networks. IEEE Sensors Journal, 15(2), 836-844. doi:10.1109/jsen.2014.2356342Flammini, A., Ferrari, P., Marioli, D., Sisinni, E., & Taroni, A. (2009). Wired and wireless sensor networks for industrial applications. Microelectronics Journal, 40(9), 1322-1336. doi:10.1016/j.mejo.2008.08.012Lopes, C. G., & Sayed, A. H. (2007). Incremental Adaptive Strategies Over Distributed Networks. IEEE Transactions on Signal Processing, 55(8), 4064-4077. doi:10.1109/tsp.2007.896034Cobos, M., Perez-Solano, J. J., Belmonte, O., Ramos, G., & Torres, A. M. (2016). Simultaneous Ranging and Self-Positioning in Unsynchronized Wireless Acoustic Sensor Networks. IEEE Transactions on Signal Processing, 64(22), 5993-6004. doi:10.1109/tsp.2016.2603972Llerena-Aguilar, C., Gil-Pita, R., Rosa-Zurera, M., Ayllón, D., Utrilla-Manso, M., & Llerena, F. (2016). Synchronization based on mixture alignment for sound source separation in wireless acoustic sensor networks. Signal Processing, 118, 177-187. doi:10.1016/j.sigpro.2015.06.023Elliott, S. J., & Nelson, P. A. (1993). Active noise control. IEEE Signal Processing Magazine, 10(4), 12-35. doi:10.1109/79.248551Elliott, S. J., Joseph, P., Bullmore, A. J., & Nelson, P. A. (1988). Active cancellation at a point in a pure tone diffuse sound field. Journal of Sound and Vibration, 120(1), 183-189. doi:10.1016/0022-460x(88)90343-4Joseph, P., Elliott, S. J., & Nelson, P. A. (1994). Near Field Zones of Quiet. Journal of Sound and Vibration, 172(5), 605-627. doi:10.1006/jsvi.1994.1202Kuo, S. M., & Morgan, D. R. (1999). Active noise control: a tutorial review. Proceedings of the IEEE, 87(6), 943-975. doi:10.1109/5.763310Burgess, J. C. (1981). Active adaptive sound control in a duct: A computer simulation. The Journal of the Acoustical Society of America, 70(3), 715-726. doi:10.1121/1.386908Elliott, S. 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Compact information technology enabled systems for intelligent process monitoring

The use of computers in industrial process applications is ever-increasing. Initially used to provide help to the machine operator, their application has evolved through automatic process control to monitoring of process health and performance. The latter, together with the quality control of the end product directly affect plant economics and ultimately the financial viability of the company. The research reported in this thesis is a contribution towards providing a cost-effective method of calculating a measure of the current health of a process and predicting any maintenance issues that may arise in the near future. Embedded systems are utilised and the monitoring system is designed to work automatically with a minimal input from the operator. This eliminates the need for peripherals such as keyboards, mice, and monitors thus reducing the overall system price and footprint. User interfaces are provided via the Internet and mobile phones giving remote access to multiple users. Single chip microcontrollers are at the heart of the embedded system rather than microprocessors, thereby reducing the relative system cost and size at the expense of localised processing power. The microcontrollers are distributed in a hierarchical network to attain the required processing power whilst minimising data storage and communications and to improve signal-to-noise ratios. The Controller Area Network (CAN) bus was selected, and used for the inter-microcontroller communications, for its robust performance in noisy environments. In the developed system architecture, each microcontroller node acquires one of the required process sensor signals and applies initial signal processing. A novel sweeping filter technique is developed to perform frequency analysis using the microcontrollers. The processed data from all nodes are then combined using situation-based criteria to reach conclusions often not evident from single sensor data. The Internet-based system is provided with the capability to upload any monitoring software or updates. Plug & play capability of the monitoring nodes is also provided so that the system can be seamlessly adapted to new or changed applications. The design and development of the system are detailed along with its deployment on various applications. Fault detection, isolation, and prediction were achieved on batch and continuous processes. A machine tool application proved the frequency analysis and network traffic reduction capabilities. On-line monitoring of an industrial valve was also performed

Performance evaluation of a distributed integrative architecture for robotics

The eld of robotics employs a vast amount of coupled sub-systems. These need to interact cooperatively and concurrently in order to yield the desired results. Some hybrid algorithms also require intensive cooperative interactions internally. The architecture proposed lends it- self amenable to problem domains that require rigorous calculations that are usually impeded by the capacity of a single machine, and incompatibility issues between software computing elements. Implementations are abstracted away from the physical hardware for ease of de- velopment and competition in simulation leagues. Monolithic developments are complex, and the desire for decoupled architectures arises. Decoupling also lowers the threshold for using distributed and parallel resources. The ability to re-use and re-combine components on de- mand, therefore is essential, while maintaining the necessary degree of interaction. For this reason we propose to build software components on top of a Service Oriented Architecture (SOA) using Web Services. An additional bene t is platform independence regarding both the operating system and the implementation language. The robot soccer platform as well as the associated simulation leagues are the target domain for the development. Furthermore are machine vision and remote process control related portions of the architecture currently in development and testing for industrial environments. We provide numerical data based on the Python frameworks ZSI and SOAPpy undermining the suitability of this approach for the eld of robotics. Response times of signi cantly less than 50 ms even for fully interpreted, dynamic languages provides hard information showing the feasibility of Web Services based SOAs even in time critical robotic applications