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Ji Z, Zhou J, Guo Y, Xia Y, Abkar A, Liang D, Fu Y. Achieving consistency of flexible surface acoustic wave sensors with artificial intelligence. MICROSYSTEMS & NANOENGINEERING 2024; 10:94. [PMID: 38974058 PMCID: PMC11226427 DOI: 10.1038/s41378-024-00727-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/16/2024] [Accepted: 05/01/2024] [Indexed: 07/09/2024]
Abstract
Flexible surface acoustic wave technology has garnered significant attention for wearable electronics and sensing applications. However, the mechanical strains induced by random deformation of these flexible SAWs during sensing often significantly alter the specific sensing signals, causing critical issues such as inconsistency of the sensing results on a curved/flexible surface. To address this challenge, we first developed high-performance AlScN piezoelectric film-based flexible SAW sensors, investigated their response characteristics both theoretically and experimentally under various bending strains and UV illumination conditions, and achieved a high UV sensitivity of 1.71 KHz/(mW/cm²). To ensure reliable and consistent UV detection and eliminate the interference of bending strain on SAW sensors, we proposed using key features within the response signals of a single flexible SAW device to establish a regression model based on machine learning algorithms for precise UV detection under dynamic strain disturbances, successfully decoupling the interference of bending strain from target UV detection. The results indicate that under strain interferences from 0 to 1160 με the model based on the extreme gradient boosting algorithm exhibits optimal UV prediction performance. As a demonstration for practical applications, flexible SAW sensors were adhered to four different locations on spacecraft model surfaces, including flat and three curved surfaces with radii of curvature of 14.5, 11.5, and 5.8 cm. These flexible SAW sensors demonstrated high reliability and consistency in terms of UV sensing performance under random bending conditions, with results consistent with those on a flat surface.
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Affiliation(s)
- Zhangbin Ji
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Jian Zhou
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Yihao Guo
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Yanhong Xia
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Ahmed Abkar
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Dongfang Liang
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ UK
| | - Yongqing Fu
- Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST UK
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Zhang Q, Wang Y, Li D, Xie J, Tao R, Luo J, Dai X, Torun H, Wu Q, Ng WP, Binns R, Fu Y. Flexible multifunctional platform based on piezoelectric acoustics for human-machine interaction and environmental perception. MICROSYSTEMS & NANOENGINEERING 2022; 8:99. [PMID: 36119378 PMCID: PMC9474866 DOI: 10.1038/s41378-022-00402-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/26/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Flexible human-machine interfaces show broad prospects for next-generation flexible or wearable electronics compared with their currently available bulky and rigid counterparts. However, compared to their rigid counterparts, most reported flexible devices (e.g., flexible loudspeakers and microphones) show inferior performance, mainly due to the nature of their flexibility. Therefore, it is of great significance to improve their performance by developing and optimizing new materials, structures and design methodologies. In this paper, a flexible acoustic platform based on a zinc oxide (ZnO) thin film on an aluminum foil substrate is developed and optimized; this platform can be applied as a loudspeaker, a microphone, or an ambient sensor depending on the selection of its excitation frequencies. When used as a speaker, the proposed structure shows a high sound pressure level (SPL) of ~90 dB (with a standard deviation of ~3.6 dB), a low total harmonic distortion of ~1.41%, and a uniform directivity (with a standard deviation of ~4 dB). Its normalized SPL is higher than those of similar devices reported in the recent literature. When used as a microphone, the proposed device shows a precision of 98% for speech recognition, and the measured audio signals show a strong similarity to the original audio signals, demonstrating its equivalent performance compared to a rigid commercial microphone. As a flexible sensor, this device shows a high temperature coefficient of frequency of -289 ppm/K and good performance for respiratory monitoring.
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Affiliation(s)
- Qian Zhang
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, 310027 Hangzhou, China
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
| | - Yong Wang
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, 310027 Hangzhou, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 310024 Hangzhou, China
| | - Dongsheng Li
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, 310027 Hangzhou, China
| | - Jin Xie
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, 310027 Hangzhou, China
| | - Ran Tao
- Key Laboratory of Optoelectronic Devices and Systems of Education Ministry and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, 518060 Shenzhen, China
| | - Jingting Luo
- Key Laboratory of Optoelectronic Devices and Systems of Education Ministry and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, 518060 Shenzhen, China
| | - Xuewu Dai
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
| | - Hamdi Torun
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
| | - Qiang Wu
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
| | - Wai Pang Ng
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
| | - Richard Binns
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
| | - YongQing Fu
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, 310027 Hangzhou, China
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST UK
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Assessment Parameters for Arrayed Pulse Wave Analysis and Application in Hypertensive Disorders. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:6652028. [PMID: 35222674 PMCID: PMC8872656 DOI: 10.1155/2022/6652028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/20/2022] [Indexed: 11/18/2022]
Abstract
Study on the objectivity of pulse diagnosis is inseparable from the instruments to obtain the pulse waves. The single-pulse diagnostic instrument is relatively mature in acquiring and analysing pulse waves, but the pulse information captured by single-pulse diagnostic instrument is limited. The sensor arrays can simulate rich sense of the doctor's fingers and catch multipoint and multiparameter array signals. How to analyse the acquired array signals is still a major problem in the objective research of pulse diagnosis. The goal of this study was to establish methods for analysing arrayed pulse waves and preliminarily apply them in hypertensive disorders. While a sensor array can be used for the real-time monitoring of twelve pulse wave channels, for each subject in this study, only the pulse wave signals of the left hand at the “guan” location were obtained. We calculated the average pulse wave (APW) per channel over a thirty-second interval. The most representative pulse wave (MRPW) and the APW were matched by their correlation coefficient (CC). The features of the MRPW and the features that corresponded to the array pulse volume (APV) parameters were identified manually. Finally, a clinical trial was conducted to detect these feature performance indicators in patients with hypertensive disorders. The independent-samples t-tests and the Mann–Whitney U-tests were performed to assess the differences in these pulse parameters between the healthy and hypertensive groups. We found that the radial passage (RP) APVh1, APVh3, APVh4, APVh3/h1 (P < 0.01), and APVh4/h1 (P < 0.05) were significantly higher in the hypertensive group than in the healthy group; the intermediate passage (IP) APVh4, APVh3/h1 (P < 0.05), and APVh4/h1 (P < 0.01) and the mean APVh3, APVh3/h1 (P < 0.05), and APVh4/h1 (P < 0.01) were significantly higher in the hypertensive group than in the healthy group, and the ulnar passage (UP) APVh4/h1 (P < 0.05) was clearly elevated in the hypertensive group. These results provide a preliminary validation of this novel approach for determining the APV by arrayed pulse wave analysis. In conclusion, we identified effective indicators of hypertensive vascular function. Traditional Chinese medicine (TCM) pulses comprise multidimensional information, and a sensor array could provide a better indication of TCM pulse characteristics. In this study, the validation of the arrayed pulse wave analysis demonstrates that the APV can reliably mirror TCM pulse characteristics.
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