A Novel RFID-Based Sensing Method for Low-Cost Bolt Loosening Monitoring

Abstract

In coal mines, bolt loosening in the cage guide is affected by the harsh environmental factors and cage hoist vibration, leading to significant threats to work safety. It is crucial, to this effect, to successfully detect the status of multipoint bolts of guide structures. This paper proposes a system to monitor bolt status in harsh environments established based on the RFID technique. A proof-of-concept model was demonstrated consisting of a bolt gearing system, passive UHF RFID tags, a reader, and monitoring software. A tinfoil metal film is fixed on the retaining plate and an RFID tag bonded to a large gear, with the bolt to be detected fixed in the center of a smaller gear. The radio-frequency signal cannot be received by the reader if the tag is completely obscured by the tinfoil, and if the bolt is loose, the tag’s antenna is exposed when the gear revolves. A radio-frequency signal that carries corresponding bolt’s information is transmitted by the RFID tag to the RFID reader due to coil coupling, identifying loose bolt location and reporting them in the software. Confirmatory test results revealed that the system indeed successfully detects bolt loosening and comparative test results (based on a reed switch multipoint bolt loosening monitor system) provided valuable information regarding the strengths and weaknesses of the proposed system.

Bolt loosening detection based on audio classification

“…The bolt loosening detection is essentially the detection and identification of the remaining amount of pretension force. In view of the different detection methods for the remaining amount of pretension force, the existing detection methods are divided into the detection method based on structural vibration signal (Guarino and Hamilton, 2014), the detection method based on the acoustic emission signal (Ding et al, 2014; Liang and Yuan, 2015; Ritdumrongkul et al, 2003; Yang and Chang, 2006), the detection method based on image recognition, and the detection method based on bolt angle and elongation (Cha et al, 2016; Park et al, 2015a, 2015b; Wu et al, 2016). The structural vibration signals mainly depend on the vibration characteristics of the structure.…”

A Review Paper on Looseness Detection Methods in Bolted Structures

“…If the looseness process and consequently any spinning happens, the change is detected by a reader and displayed in interface software. Experiments have shown that the relationship between the reader and the tag for angles lower than 20 degrees yields best efficiency (Wu, et al, 2016).…”

Screw Relaxing Detection With UHF RFID Tag

“…For what the latter is concerned, the detection of potential unsafe circumstances is surely important in vehicular as well as industrial environments, and it has already been investigated for applications in the context of structural health monitoring [17]. Cracks, corrosion, strains, bolt loosening, etc., are some possible structural circumstances where RFID tag sensors have been applied successfully [18], [19]. In this sense, screw relaxing is a situation which is rarely monitored (except for the manual inspection), even if it many times could be crucial for safety.…”