Browsing by Subject "Fieldbus"

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Open Access
A modular real-time fieldbus architecture for mobile robotic platforms
(Institute of Electrical and Electronics Engineers, 2011-03) Saranlı U.; Avcı, A.; Öztürk, M. C.
The design and construction of complex and reconfigurable embedded systems such as small autonomous mobile robots is a challenging task that involves the selection, interfacing, and programming of a large number of sensors and actuators. Facilitating this tedious process requires modularity and extensibility both in hardware and software components. In this paper, we introduce the universal robot bus (URB), a real-time fieldbus architecture that facilitates rapid integration of heterogeneous sensor and actuator nodes to a central processing unit (CPU) while providing a software abstraction that eliminates complications arising from the lack of hardware homogeneity. Motivated by our primary application area of mobile robotics, URB is designed to be very lightweight and efficient, with real-time support for Recommended Standard (RS) 232 or universal serial bus connections to a central computer and inter-integrated circuit (I(2)C), controller area network, or RS485 bus connections to embedded nodes. It supports automatic synchronization of data acquisition across multiple nodes, provides high data bandwidth at low deterministic latencies, and includes flexible libraries for modular software development both for local nodes and the CPU. This paper describes the design of the URB architecture, provides a careful experimental characterization of its performance, and demonstrates its utility in the context of its deployment in a legged robot platform.
Open Access
The Universal robot bus : a local communication infrastructure for small robots
(2008-12) Avcı, Akın
Design and construction of small autonomous mobile robots is a challenging task that involves the selection, interfacing and programming of a large number of sensor and actuator components. Facilitating this tedious process requires modularity and extensibility in both hardware and software components. This thesis concerns the development of a real-time infrastructural architecture called the Universal Robot Bus (URB), based on the popular Inter-Integrated Circuit (I 2C) bus standard. The main purpose of the URB is the rapid development and realtime interfacing of local nodes controlling small sensor and actuator components distributed on a mobile robot platform. It is designed to be very lightweight and efficient, with real-time support for RS232 or USB connections to a central computer. The URB infrastructure is inspired from the RiSEBus architecture, which is also an internal communication protocol for mobile robots, and developed to fit our requirements. URB offers a modular and extensible architecture for rapid and frequent changes to the platform design. Mobile robots also need to perform accurate sensory processing and estimation in order to operate in unstructured environments. Hence, the URB also supports real-time operations with reliable hardware and software components. The first novel contribution of this thesis is the design and implementation of automatic synchronization of data acquisition across multiple nodes. Our synchronization algorithm ensures that each node completes data acquisition tasks simultaneously well before read operations. Our experiments also prove that each individual node acquires data at approximately the same time instant. The second major contribution of this thesis is the incorporation of automated and unsupervised data acquisition across multiple nodes into the URB protocol. Autonomous data acquisition helps acquire periodic and frequently needed data over nodes. This enhancement reduces the computational load on the central processing unit and reduces bandwidth costs over the communication medium. This thesis also servers a survey on network architectures and protocols, network applications in robotics, synchronization algorithms, and applications of synchronization in robotics besides implementation details of the URB.