A computer-vision based vibration transducer scheme for structural health monitoring applications

Abstract

It is known that the structural health monitoring (SHM) applications rely on the physical data obtained from in-situ measurements. In this view, various instruments such as accelerometers, strain gauges, displacement sensors are used to collect data, which are to be used in structural identification applications. Considering the basic requirements like precision, accuracy and applicability for reliable data post-processing, a new scheme for a vibration sensing device is introduced in this study. The proposed sensor scheme is a vibration transducer which combines the fundamental sensing principles of conventional accelerometers and the computer vision techniques. Basically, the transducer consists of a mechanical system as the primary sensor and a camera as the secondary sensor. In conventional piezoelectric (PE) accelerometers, the PE material generates charge or voltage which is proportional to the acceleration applied to the sensor. Subsequently, this charge or voltage is measured and used to determine the imposed accelerations. However, in the proposed vibration transducer, the motion of the seismic mass is directly tracked by a camera and the displacements are extracted using computer vision algorithms. Afterwards, displacement of the seismic mass can be related to the imposed acceleration, velocity and displacement. In this study, the transducer concept was realized practically using two different primary sensors consist of a spring-mass system and a cantilever beam together with a smartphone's camera. The concept was tested on a laboratory structure in order to verify its capabilities in modal identification, damage detection and localization applications. The comparison of the results obtained by the proposed transducer and the conventional accelerometers has shown that the proposed vibration transducer is capable of both identifying modal parameters and detecting damage despite its crude design. Although the sensitivity of the transducer is lower than the conventional accelerometers in its current state, the concept is prone to further improvements.

Computer Vision and Image Processing in Structural Health Monitoring: Overview of Recent Applications

“…The analysis revealed that several sensors had been used for validation purposes, including laser displacement sensors [32,34,41,42,49,70,74,76,82], accelerometers [32][33][34]50,51,53,55,59,61,[64][65][66][67][68]76], IMU [60], linear variable differential transformers [34,36,41,50,54,61,66,67,73], laser Doppler vibrometers [38,46], stationary cameras [42,75,83], actuators [71], laser trackers [81], infrared sensors [48], and marker-based systems [44,73]. Marker-based systems are routinely used in other fields (such as medicine), where they are the traditional reference systems for motion capture and analysis.…”

“…This choice applies to the following studies: [34,[40][41][42]44,45,[48][49][50][51][53][54][55][58][59][60][61][62][63][64]66,67,[69][70][71][72][73][74][75][76][77][78][80][81][82]. In a few cases, the experimental scenarios were outdoors where, on the other hand, it was necessary to consider, at least in part, the environmental conditions and the problems previously indicated, testing the solution on scale models in most cases as well.…”

Vision-Based Vibration Monitoring of Structures and Infrastructures: An Overview of Recent Applications

“…(2) measurements of displacement time histories in prototypes or small-scale structures in controlled environmental conditions, typically in a laboratory, ; (3) field measurements of displacement time histories in full scale structures ; (4) development of sensors using vision-based techniques [201][202][203][204][205][206][207]; and (5) field measurements of moving components, as in the case of wind turbines, e.g., [208][209][210][211]. Such a subdivision is made regardless of the adopted vision-based techniques and image processing algorithms.…”

Triboelectric Rotary Motion Sensor for Industrial-Grade Speed and Angle Monitoring

“…Sensor technology is one of three central pillars in modern information technology [1,2] and is applied widely in the fields of industrial automation, automotive electronics, and communication technology [3][4][5]. It has become an indispensable criterion for measuring the development of scientific research and industrial manufacturing.…”