“…To avoid the problems of friction, lubrication, and clearance caused by traditional motion pairs, flexure hinges are usually used to transmit force and displacement (Cai et al, 2016; Zhu et al, 2016a). At present, the commonly used actuators are voice coil motors (VCMs) (Zhang and Xu, 2018, 2019), electromagnetic actuators (Sun et al, 2014), piezoelectric actuators (PZTs) (Liu and Li, 2016; Ting et al, 2011), and so on. PZTs have been widely used because of their advantages: no noise, no heat, fast response, and high displacement resolution.…”