Attribute/Service Model: Design Patterns for Efficient Coordination of Distributed Sensors, Actuators and Tasks in Embedded Systems

This paper proposes the Attribute/Service Model (ASM) and associated design patterns as a general and simple framework for applications that require programming with multiple tasks on multiple embedded processors. This model enables the programming of complex tasks with multiple sensors and actuators on highly distributed yet tightly coupled systems by: using a simple unified protocol for communication; allowing the access to attributes or the running of services to be independent of where such attributes or services reside; protecting shared resources, and simplifying the synchronization of multiple processes in multiple processors. Associated design patterns such as the event/trigger mechanism and general event-driven control are developed on ASM. ASM is designed for the coordination of distributed sensors, actuators and computational tasks on modular self-reconfigurable robots. However it may be used for any multi-threaded distributed embedded control network. Unlike the most existing distributed objects, ASM can be implemented on embedded systems with small footprints. ASM has been implemented both in C on top of VxWorks on the MPC555 embedded microprocessor, and in Java on PC. The Controller Area Network (CAN) has been used as the communication medium. It could be equally implemented on any real-time operating system using any communication media.