Piezoelectric inertial rotary actuators based on asymmetrically clamping structures

This paper presents innovative piezoelectric inertial rotary actuators based on asymmetrically clamping structures, which apply magnetic force to improve driving performance. By using a pretightening force control device, the designed actuators can realize high accuracy and stability. To test the influence of magnetic force on the driving property, two types of actuators are fabricated and investigated. Piezoelectric-driven force is the only driving source of the first actuator type, whereas magnetic force is applied to the second actuator type. An experimental system is built to test the performance of the actuators under different frequencies, voltages, and pretightening torques. Experimental results indicate that the stable minimum output stepping angle is 0.85 μrad under a square signal of 20 V, 6 Hz and a pretightening torque of 2.475 N mm. Under the condition of 8 Hz and 100 V, the maximum angle velocity and output force can reach 4.02 rad/s and 0.98 N, respectively. The proposed actuators not only achieve a stable and accurate rotary motion but also realize a large output force and a fast velocity, thus contributing to the application of pretightening force control device and magnetic force.