Performance Evaluation and Reliable Implementation of Data Transmission for Wireless Sensors on Rotating Mechanical Structures

Wireless sensors are increasingly adopted in mechanical, civil, and aerospace engineering systems to acquire and wirelessly transmit sensed information to data receivers for structural health or machine condition monitoring. Wireless data transmission performance in such engineering systems was known to depend greatly on sensor positions and possible relative motions with respect to the environment. Pronounced performance deterioration can occur under certain sensing conditions such as that of a rotating engineering structure monitoring system. Various studies have applied wireless sensors on rotating mechanical structures for condition monitoring, but a systematic study of their data transmission performance is still missing. This study is devoted to characterizing such performance of wireless sensors on a rotating lathe spindle and further examining the efficacy of a commonly adopted automatic repeat request (ARQ)-based reliable transmission method. The experimental measurements have shown that the transmission error rates were proportional to rotation speeds at certain receiver locations, while a minor change in the receiver location could significantly alter such dependency. It was found that the ARQ approach effectively assured a reliable data transmission during rotation with little retransmission overheads, and the reliable transmission throughput varied with different packet sizes and packet generation intervals.