A Novel Structural Health Monitoring System with Wireless Power and Bi-directional Data Transfer

This paper proposes a novel structural health monitoring (SHM) system for wireless sensor node (WSN) that enables power and physical data of WSN to be transmitted bi-directionally. The main point is system overview, the analysis, and implementation of proto-type SHM system. Conventional method of data transmission for SHM system is cable based sensor or WSN with battery. These result in high maintenance cost. To improve them, a novel SHM system with wireless power and data transfer (WPDT) is proposed. The proposed system has a WSN, primary control switch, load variation switch, and a modulation circuit for data transmission. It detects packetized digital data of the WSN by using load variation switch with WPDT method. Then, these demodulation circuit converts them to WSN data. Therefore, the proposed SHM system can reduce maintenance cost of the smart bridge by eliminating the communication module for data transmission. The WPDT method is implemented to assess validity. Wireless power is transferred to the WSN with a distance of 300 mm under concrete structure with steel rebar array. In addition, data transmission is properly conducted between primary resonator side and secondary resonator side with a 500bps data rate. Finally, a proto-type SHM system for the WSN has been built to experimentally evaluate the effectiveness. The results show that it operates the WSN by using wireless power and enables the WSN to transmit physical data of a smart bridge for damaged or undamaged conditions.