A four-beam piezoelectric transducer for energy harvesting and tissue hardness detection

• Published in: Mechanical systems and signal processing 2025-02, Vol.224, p.111971, Article 111971
• Main Authors: Zhang, Jiantao, Cong, Xingang, Yu, Xiangfu, Luo, Yi, Li, Yanlong
• Format: Article
• Language: English
• Subjects: Energy harvester; Finite element analysis; Hardness detection; Piezoelectric; Tactile sensor; Theoretical model
• ISSN: 0888-3270
• DOI: 10.1016/j.ymssp.2024.111971

This paper develops a piezoelectric device that can be used for both vibration energy harvesting and soft tissue hardness detection. The piezoelectric transducer allows for simultaneous energy harvesting and hardness testing. When the piezoelectric transducer is used as an energy harvester, the four-beam piezoelectric vibration energy harvester has a good voltage output when the angle α between each beam of the harvester and the base plane is 0°. The output power is maximum when the external load resistance is 100 kΩ. When the piezoelectric transducer is used for hardness detection, the feasibility of the hardness measurement scheme is verified by simulation analysis. By simulating the results of contact materials with different hardness levels, a calibration curve for the sensor’s modal frequency and the elastic modulus of the tested object was fitted. Finally, a prototype four-beam piezoelectric sensor for energy harvesting and tissue hardness detection was fabricated. An experimental platform for vibration energy harvesting and soft tissue hardness detection was developed and different experiments were conducted. When the piezoelectric transducer is used as an energy harvester, the experimental results of the output characteristic change curve are basically consistent with the simulation results. The maximum rms output voltage of the harvester is about 423 mV and the maximum output power is about 1.79 μW. When piezoelectric sensors are used as hardness detection sensors, it has high accuracy within the range of 0 ∼ 800 kPa. The sensor can effectively detect the location of hard objects within soft samples and identify the hardness of the tested samples.