Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China.
Sensors (Basel). 2021 Mar 3;21(5):1736. doi: 10.3390/s21051736.
Previous studies on Lamb wave touchscreen (LWT) were carried out based on the assumption that the unknown touch had the consistent parameters with acoustic fingerprints in the reference database. The adaptability of LWT to the variations in touch force and touch area was investigated in this study for the first time. The automatic collection of the databases of acoustic fingerprints was realized with an experimental prototype of LWT employing three pairs of transmitter-receivers. The self-adaptive updated weight coefficient of the used transmitter-receiver pairs was employed to successfully improve the accuracy of the localization model established based on a learning method. The performance of the improved method in locating single- and two-touch actions with the reference database of different parameters was carefully evaluated. The robustness of the LWT to the variation of the touch force varied with the touch area. Moreover, it was feasible to locate touch actions of large area with reference databases of small touch areas as long as the unknown touch and the reference databases met the condition of equivalent averaged stress.
先前的 Lamb 波触摸屏（LWT）研究基于这样的假设，即未知触摸具有与参考数据库中的声纹一致的参数。本研究首次调查了 LWT 对触摸力和触摸面积变化的适应性。使用 LWT 的实验原型实现了声纹数据库的自动采集，该原型采用了三对发射器-接收器。自适应更新所使用的发射器-接收器对的加权系数，成功地提高了基于学习方法建立的定位模型的准确性。仔细评估了改进后的方法在使用不同参数的参考数据库定位单触和双触动作的性能。LWT 对触摸力变化的鲁棒性随触摸面积而变化。此外，只要未知触摸和参考数据库满足等效平均应力条件，就可以使用小触摸区域的参考数据库来定位大面积的触摸动作。
