A high resolution piezoelectric platform with large travelling stroke based on crystal stacks

The precision positioning platform driven by piezoelectric actuators is in high demand in the fields of precision positioning, manufacturing, and optics. Although various designs for piezoelectric-driven positioning platforms have been proposed, the motion range and resolution are mutually constrained, which severely hinders their applications. Additionally, the hysteresis and creep nonlinearity of piezoelectric stack actuators (PSAs) pose significant challenges for the high-precision tracking and positioning control of piezoelectric platforms. To address the issues of mutual constraints between output displacement and resolution, as well as high hysteresis, we employed the piezoelectric crystal Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PIN-PMN-PT) to manufacture the PSA. Meanwhile, the mechanical structure design of the piezoelectric platform adopted a two-stage mechanical amplification structure featuring lever and bridge designs, effectively enhancing the output displacement of the platform. Furthermore, it incorporated a double parallel flexible hinge guiding structure and a parallelogram configuration to improve the resolution of the piezoelectric platform, which also plays a crucial role in protecting the PSA. Experimental results indicate that the piezoelectric platform can achieve an output displacement of 129 µm under a load of 4.5 kg. Simultaneously, this platform maintains a minimum displacement resolution of 3 nm, with a range-to-minimum resolution ratio of 43,000, which is higher than that of other reported platforms. Additionally, the hysteresis of the crystal PSA and the piezoelectric platform was reduced by 2–3 times, with the platform's hysteresis being lower than that of single crystal PSA, indicating that the platform's structure has a suppressive effect on PSA hysteresis.