Application of Piezoelectric Actuator/Sensor and Lamb Wave for Touch Recognition
| Autor: | Yan-TingLin, 林彥廷 |
|---|---|
| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 This thesis developed an ultrasound signal receiving and transmitting system based on piezoelectric transducers made of PZT ceramics. One of the transducers can excite Lamb waves in a thin plate and others can detect the Lamb wave signals. Both phase and group velocity of the excited Lamb waves can be calculated and then compared with experimental data. This Lamb wave ultrasound system will be applied to a touching panel to sense the position of human’s fingers. In theoretical simulation, a commercial finite element software COMSOL Multiphysics® is adopted to optimize the performance of this PZT-based Lamb wave transmitting/receiving system. A quasi-2D effective area method has been developed and tested in order to reduce the computing time to an originally 3D problem in wave physics. Good results are obtained and are well in agreement with experimental data. For the application on touching and positioning panel sensors, this thesis studied the sensitivity and signal differences in Lamb waves when finger is touching at different positions of the plate. Optimal operating frequency and mode of Lamb waves are determined first both theoretically and experimentally. A configuration of deploying several PZT transducers on the plate and an algorithm for processing the received signal waveform are established for locating the position of finger tip touched on the plate. It shows that we can locate the position with an accuracy of 2.3 mm. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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