A resonance-mode piezoelectric device for measurement of respiratory mechanics
This paper presents the design of a novel oscillometry device for the measurement of respiratory mechanics based on piezoelectric bimorph actuator technology. To predict performance for measurement of human respiratory mechanics, a dynamic model was developed based on a bimorph piezoelectric actuator driving a linear resistance mesh screen including subject’s respiratory impedance loads, and realistic breathing noise. Model performance was also validated in a prototype device. We found that while breathing noise substantially lowered SNR, the model could produce sufficient pressure and flow for acceptable SNRs exceeding 35 dB, and accuracies exceeding 99%. Satisfactory accuracy could be achieved with load impedance errors less than 3%. Maintaining the air-gap around the oscillating mesh with a resistance against the leak greater than 0.38 cmH2O/L/s maintained good performance, with an acceptable 4 dB decrease to SNR. Moreover, this work provides multiple solutions to host higher amounts of noise and nonlinearities. These results indicate that the development of an accurate lightweight portable single frequency FOT device is feasible.