Control of cyber-physical systems using Bluetooth Low Energy and distributed slave microcontrollers

Abstract

In this paper, Bluetooth Low Energy is used for communication between master computers and distributed slave microcontrollers that perform low-level tasks that the master is unable or not suitable to do, e.g. hard real-time and low-level I/O. The wireless communication with the master computer allow slaves to be added, replaced or removed without the need for rewiring. Dependability can be increased as implementation of redundancy, both for masters and slaves, does not require wired connections between them. This concept has been utilized in an industrial prototype and evaluated in an experiment presented in this paper. The experiment evaluated the communication latency with Bluetooth Low Energy, compared to a wired alternative, which is important for reliable operation. The results showed a similar average latency, but the worst case was less favorable for Bluetooth Low Energy. However, since the slaves are intended to manage time critical operations locally, with the master computer in a supervisory role, these delays will be acceptable in many applications, when considering the advantages of a wireless master-slave communication.