Substantial improvement of rotation driving accuracy is urgently needed and facing challenges. Miniature bidirectional rotary actuators with high-precision and controllable fallback rate require novel driving principles. Here, on the basis of a proposed biomimetic stick-slip motion principle, a novel piezoelectric-thermal coupling bidirectional rotary actuator was developed. The integrated mantis grasping leglike biomimetic claws and heating rods could realize the clockwise macroscopic rotation and anticlockwise macroscopic fallback of a cylindrical rotator, generated by piezoelectric stick-slip and thermal expansion, respectively. The rotation fallback was effectively inhibited at relatively lower frequencies and higher voltages, as a slight fallback rate of 0.095 was confirmed in term of 0.5 Hz and 80 V. An extraordinary piezoelectric-driven macroscopic rotation resolution of 0.2 μrad and thermal-induced microscopic resolution of 0.00073°/°C were experimentally revealed with the aid of real-time observation of the clockwise slow sticking and anticlockwise instantaneous slipping processes by using three-dimensional optical imaging.
Keywords: biomimetic design; high resolution; piezoelectric-thermal coupling; rotary actuator; stick−slip.