“…Additionally, the two superposed sines waveform and sine waveform usually excite the actuators for driving in the resonance state to improve the output power (Bansevicius and Blechertas, 2008;Chu et al, 2016;Lee et al, 2007;Nishimura et al, 2012;Pan et al, 2019;Suzuki et al, 2012;Yu et al, 2020). In many studies, the waveforms were introduced buffer stages at the rising or falling edge (Fan et al, 2019;Liu et al, 2019a;Qin et al, 2019c;Tang et al, 2020;Tian et al, 2019;Wang and Lu, 2012;Yang et al, 2019Yang et al, , 2020bZhong et al, 2019aZhong et al, , 2019bZhong et al, , 2020Zhu et al, 2018), see Figure 2(h); the works of Wang et al and Zhong et al stated that the waveforms introduced the buffer stages got better driving performance, including step displacement and speed, which are presented in Table 1. This is owing to the creep characteristics of piezoelectric transducers, and a proper buffer stage is helpful to make them elongate more fully and contract more effectively, so the waveform with buffer stage is often used in practical applications as well.…”