Piezoelectric hybrid actuation mode to improve speeds in cross-scale micromanipulations

Piezoelectric precision actuators are powerful tools used to explore and reform the microworld. A large number of achievements have emerged to promote their progress. However, most of them only focus on high accuracies and large workspaces, but ignore the roles of fast speeds for high working efficiencies and wide application fields. Inspired by the wobbling and jumping gaits of the cricket, a hybrid actuation mode for piezoelectric actuators is proposed to improve speeds in cross-scale micromanipulations. After solving three key problems of physical design, operation method and control strategy, this idea is verified with FEM simulations and theoretical models. The experiments indicate that the hybrid mode increases the speed by about 300% over the conventional walking mode, and the maximum speed reaches about 3.9 mm/s (0.16 rad/s). Furthermore, the resolution is as high as 3.8 nm (0.14 μrad), and the RMS positioning error is smaller than 34.2 nm in a stroke of 1 mm. With unlimited stroke, fast speed and high precision, the hybrid mode is very suitable for the accurate quick positioning in a large range. The experiment also demonstrates great potential applications in micro-nano assemblies. To sum up, the hybrid mode significantly improves the speeds of piezoelectric actuators under the premises of high accuracies and large workspaces. Besides, this mode is a universal approach, which can be easily applied on other actuators to improve speeds, so it is helpful to expand applications of piezoelectric precision actuators.