Reliability evaluation of reconfigurable conveyor systems

Conveyor systems are critical in automation applications such as material handling and packaging. Networked embedded devices, such as tiny microcontrollers that are integrated with sensors, actuators and low power radio transceivers, significantly impact the design of future such systems by offering flexible topologies, reduced wiring costs and distributed controllers. Because the application domains of such systems are critical, these systems are expected to have high reliabilities. As a result, to exploit the benefits offered by the emerging technologies, a study of the reliability of such systems that are regulated by an integrated, embedded, distributed collection of microcontrollers is important. We present a model-based approach to evaluate the reliability of composable conveyor systems based on the fault tree modeling paradigm. We illustrate how the methodology provides valuable guidance to navigate the design space of these systems using several examples. Our results indicate that while using redundant sensors has little effect on system-level reliability, wireless link reliability has a significant impact. In the future, a similar methodology can be developed to evaluate the reliability of composable automation systems in which stations operate on entities moving over a conveyor system.