Latency Aware and Event-Based Wireless Control for Cloud-Fog Automation

Sammanfattning

The development seen within industrial automation in recent years enables the emergence of manufacturing sites that utilise technology for improved productivity, quality and safety. Increased communication demands introduced by Industry 4.0 have motivated the development of cloud-fog automation; a technique characterised by wireless communication between lower levels of the automation pyramid. Specifically, the new communication requirements gives rise to the need for efficient wireless communication between input/output devices and controllers. This thesis presents findings from an investigation of wireless control and communication performance. A cascaded internal model control-based Proportional, Integral, Derivative controller structure is developed to control a time-critical motion system. Various communication protocols and control algorithms are considered to examine the performance behaviour. The results indicate that user datagram protocols, compared to transmission control protocols, are a promising candidate for the target purpose. However, by manipulating the control algorithm sampling interval, transmission control protocol communication yields almost equivalent control performance results. An exploration of event-based control results in an algorithm that achieves communication reductions of over 80%. Given a consciously chosen sampling interval, control performances comparable to those of the corresponding time-based system can be maintained. The research indicates that wireless control has the potential to accomplish control performances equal to those found in wired systems.