Modular Sensor for Detecting Cable Faults of Cable-Stayed Bridge

For detecting cable faults, a climbing robot was developed with a proposed modular magnetic sensor attaching on it. The modular sensor, made up of a number of sensor units, embraced the cables as a wreath at equal angle. Each sensor unit consisted of two permanent magnets and one Hall sensor. This module could be installed and accommodated conveniently by meanings of changing the number of the sensor units, by adjusting the relative distance between the two connecting pieces, or by regulating the angle of two connecting pieces. Mechanical structure and measuring circuit were introduced. Based on the detrending algorithm, the effect of distance was successfully eliminated and the error signals were extracted effectively. Testing experiments on a man made cable with faults showed the effectiveness of the modular sensors and the detecting method.