Exploiting the CAN bus as a potential interface for future aerospace vehicles based on a modular, intelligent, and autonomous architecture

Paper number

IAC-06-B5.7.04

Author

Mr. Carlo Del Vecchio Blanco, University of Naples "Federico II", Italy

Coauthor

Prof. Marco D Errico, Seconda Universita di Napoli, Italy

Year

2006

Abstract

Future needs of a number of space missions (exploration, civil and military observation, communication) drive towards systems able to self-monitor, adapt to failures, and reconfigure. In addition, most of these missions are to be realized by integrating a number of platforms, eventually acting as a single entity (formations). In order to fulfil all arising requirements, a change of perspective is needed in aerospace vehicles design. An architecture building on modular components and subsystems, which are in turn intelligent to perform self-monitoring and control functions, allows to integrate a system with different levels of internal autonomy and able to be incrementally realized. Such an architecture also allows cost reduction, faster realization cycles, and faster technology insertion and upgrade.
If on the one hand subsystems modularity allows to meet a wide range of missions requirements and autonomy eases system reconfiguration, on the other hand this architecture poses challenging requirements on internal interfaces (electrical, mechanical, and data). With reference to data interface, a large number of data, interrogations, commands and software updates have to be generated and managed by means of a versatile and safe data bus.
The proposed paper presents a deep analysis aimed at identifying, implementing, and validating at prototype level the data bus best suited for the above described architecture. In particular, FIP (Factory Instrumentation Protocol), Profibus (PROcess Field BUS), Interbus-S, SERCOS (SErial Real time COmmunication System), MIL-STD-1553, SpaceWire, I2C and CAN bus protocols have been compared. Major attention is paid to the possibility to simply increase the number of connected devices (new sensors, cameras, robotics arm and so on), achieving a sort of plug and play configuration. The problem to simplify the connection between subsystems, through a multimaster and broadcast medium organization, and finally to reduce the cost have been also analyzed. 
Thanks to its built-in features of error detection (Bit error, stuff error, CRC error, form error, acknowledgment error), CAN bus, which is a CSMA/CD (Carrier Sense Multiple Access/ Collision Detection) communication protocol, is a potential interface for the considered architecture. To confirm this choice a test campaign is reported with several PIC microcontroller nodes simulating platform components and a PC104-plus (Ampro CoreModule 600 with a 400MHz UltraLow Celeron) simulating the on-board computer. In particular, message latency time, capability of resolving message arbitration, and error identification and isolation are characterized.

Abstract document

IAC-06-B5.7.04.pdf

Manuscript document

IAC-06-B5.7.04.pdf (🔒 authorized access only).

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