Development of RTOS-based wireless SHM system: Benefits in applications

The emergence of wireless smart sensor platforms with powerful computational capabilities has had broad impacts in the field of structural health monitoring (SHM), enabling numerous applications in civil infrastructure. However, as the demands of wireless SHM systems increase, certain properties of event-driven operating systems for these sensor nodes, such as the TinyOS operating system of the iMote2, begin to impose limitations on the development of SHM systems. The problematic characteristics include static resource allocation, single-Application focus, lack of real-Time scheduling support, and dependence on a non-standard programming language. To address these limitations, we consider the use of a real-Time operating system (RTOS), commonly used for industrial control systems and similar applications, as an alternative solution in the development of Xnode, the next-generation smart sensor platform for civil engineering applications. In this paper, features of the RTOS environment are first analyzed systematically and compared with TinyOS to demonstrate how it addresses the major concerns of event-driven operating systems. A distributed data acquisition application from the Illinois SHM Services Toolsuite for the iMote2 is implemented as a demonstration of the RTOS-based framework and its advantages. Most importantly, benefits of the RTOS- based wireless SHM system are catalogued comprehensively, with a particular focus on flexible application framework and a more engineer- friendly environment.