“…In piezoelectric systems, the conversion between mechanical energy and electrical energy has many applications in industry (Smith, 2005). Nowadays, piezoelectric elements find numerous applications in precise positioning systems (Li, Zhang, Jia, & Qian, 2009;Liu, Yan, & Özbay, 2018;Qiu, Wang, Zhang, & Han, 2013;Salvador, Plazas, Gimeno, & Carreres, 2012;Stefanski, Minorowicz, Persson, Plummer, & Bowen, 2017;Tian et al, 2019;Wang, Ho, & Jiang, 2021), hard disc drive systems (Khasawneh, Jaradat, Naji, & Al-Azzeh, 2018;Lim & Choi, 2007;Ohashi, Kajiwara, Iwadare, & Arisaka, 2005), vibration control (Chuaqui, Roque, & Ribeiro, 2018;Høgsberg, 2021;Pu, Zhou, & Meng, 2019), energy harnessing (Chelli et al, 2021;Guigon, Chaillout, Jager, & Despesse, 2008;Jacquelin, Adhikari, & Friswell, 2011;Kundu & Nemade, 2016;Moro & Benasciutti, 2010;Peigney & Siegert, 2013;van den Ende, van de Wiel, Groen, & van der Zwaag, 2011;Wu, Bao, & Wang, 2021;Xiang, Wang, Shi, & Zhang, 2013;Yatim, Ismail, S.J, hj.bakri, & Effendy, 2018) etc. Due to the interaction between the foot and the contact surface during walking, human footsteps produce vibrations and sound from a few Hertz to ultrasonic frequencies(A. .…”