Abstract: This study presents a piezoelectric rotary actuator which is equipped with a bionic driving mechanism imitating the centipede foot. The configuration and the operational principle are introduced in detail. The movement model is established to analyze the motion of the actuator. We establish a set of experimental system and corresponding experiments are conducted to evaluate the characteristics of the prototype. The results indicate that the prototype can be operated stably step by step and all steps have high reproducibility. The driving resolutions in forward and backward motions are 2.31 µrad and 1.83 µrad, respectively. The prototype can also output a relatively accurate circular motion and the maximum output torques in forward and backward directions are 76.4 Nmm and 70.6 Nmm, respectively. Under driving frequency of 1 Hz, the maximum angular velocities in forward and backward directions are 1029.3 µrad?s−1 and 1165 µrad?s−1 when the driving voltage is 120 V. Under driving voltage of 60 V, the angular velocities in forward and backward motions can be up to 235100 µrad?s−1 and 153650 µrad?s−1 when the driving frequency is 1024 Hz. We can obtain the satisfactory angular velocity by choosing a proper driving voltage and frequency for the actuator.

Key words: bionic foot, piezoelectric rotary actuator, centipede foot, stick-slip