In this work, a novel tunable diaphragm structures are designed as sensing diaphragms for ultrasonic sensors. The natural frequency and sensitivity of the new structure diaphragms is simulated by finite element method. The proposed membrane structures is outer-ring clover (ORC) structure. Typically, an increase in membrane sensitivity is accompanied by a decrease in its natural frequency. However, this can be significantly mitigated by the proposed structures, which can exhibit notable structural optimization effects by simultaneously enhancing sensitivity and minimizing the reduction of the natural frequency. The simulation results indicate that, when the outer diameter and thickness remain unchanged, the sensor can achieve a maximum sensitivity improvement of 3.5 times and a reduction of 1.25 times in the natural frequency compared to the circular diaphragms (CD). Furthermore, ORC can be fabricated by micro-electromechanical systems (MEMS) technology, making it feasible for practical manufacturing and production. The sensing membrane is expected to be applicable in detection fields such as ultrasound partial discharge and underwater acoustics.
A Fiber Bragg Grating (FBG) based force sensor with high-sensitivity and temperature compensation capability. It can be used to accurately measure the contact force (CF) between medical equipment and tissues or organs in minimally invasive surgery (MIS). To achieve temperature compensation, a novel design incorporating dual elastomer-based dual FBGs is employed, and its effectiveness is verified through finite element simulation. After temperature compensation, the developed sensor has a sensitivity of 54 pm/N, a resolution of 0.019 N, and a root-mean-square error (RMSE) of 0.064 N. The utilization of temperature disturbances for measuring distal contact force demonstrates a substantial enhancement compared to direct measurement methods. Additionally, in vitro experiments are conducted using a silicone vascular model, demonstrating the sensor’s capability to detect certain alterations in vascular pathways. Finally, a simulated palpation liver experiment confirmed that the designed force sensor can preliminary detect of the relative hardness of the tissue based on the magnitude of the CF. In vitro experiments have proved that the designed FBG force sensor has a practical value in MIS.
To mitigate the failure of a Hilbert transform-based fixed-threshold multi-peak demodulation algorithm in distributed Fiber Bragg Grating (FBG) sensing systems with light noise, an adaptive multi-peak demodulation algorithm based on the Hilbert transform is proposed in this paper. The algorithm adopts the thought of Divide and Conquer, including reflection spectrum segmentation and single peak detection. Multiple sub-spectra of the FBG multi-peak spectrum is segmented by the Hilbert transform and calculating adaptive threshold method, and then the Gaussian fitting algorithm is used to achieve the precise positioning of the spectral peaks. Theoretical analyses and simulation results show that the algorithm using an adaptive threshold as a threshold of splitter can greatly improve the portability of the algorithm in complex situations, and improve the algorithm’s noise resistance, demodulation speed, and accuracy. It shows that the algorithm provides a new way of demodulation for distributed FBG sensing systems.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.