Robustness evaluation of structural vibration estimation by self-sensing stand-alone harvester

抄録

Sensing the state of structures, such as automobiles, factory machines, and buildings, is essential for structural health monitoring and structural vibration control. Strain, displacement, and acceleration sensors can measure the structural information; however, these sensors require certain installation spaces, wiring between sensors and data loggers, and electricity for data recording. To solve these technical subjects associated with the sensor installation, we have proposed a self-sensing technique with a stand-alone harvester. The technique estimates the structural information from piezoelectric voltage generated from a piezoelectric transducer inserted in a target structure. Because the piezoelectric voltage is proportional to the mechanical displacement and the electric charge, the proposed observer can estimate both electrical and mechanical information from the harvester. The transducer acts as two roles: a sensor utilized for self-sensing technique and an energy scavenger converting mechanical vibration energy to electrical energy. The scavenged electrical energy is applied to sense the piezoelectric voltage, which is calculated to estimate the structural displacement and velocity from the sensed voltage information. To achieve this objective, an alternately switching observer based on the Kalman filter theory has been introduced. The scavenging performance is enhanced by an appropriate mechanism for circuit connection changing. This paper reports the estimation performance of the proposed self-sensing method through an experiment under a noisy observation value condition. This consideration supposes real-environment operation. The estimation performance of the self-sensing method was evaluated by indirectly determining the harvesting performance. The experimental results showed that the proposed method can accurately estimate the state values under noise-contaminated conditions.