An asymmetrical inertial piezoelectric rotary actuator with the bias unit

A novel piezoelectric inertial rotary actuator with a bias unit that is based on asymmetrical clamping structures was presented in this paper. Under the same circumstance, the designed actuator with symmetrical electrical signals produced a relatively larger inertial driving moment difference because of the existence of the bias unit. Mechanical analysis was derived and the simulation model of the bias unit was built to ascertain the influence of structural parameters on output performance. A prototype with a bias unit, a carrying device and a friction adjusting device was fabricated and an experimental system was built to evaluate the performance in terms of output displacement, angular velocity, driving moment and bearing capacity. Both simulation and experimental results indicated that the bias unit improved angular velocity and output force to some extent. Compared with the actuator without a bias unit, the actuator with the offset distance of 15 mm enhanced the maximum angular velocity by approximately 54.88% from 3.48 rad/s to 5.39 rad/s under 100 V, 23 Hz and the highest driving moment by 50.2% from 2.41 N mm to 3.62 N mm. Angular displacement resolution reached 14.3 μrad under 15 V, 1 Hz and heavy bearing capacity attained 1300 g under 100 V, 4 Hz. In general, the proposed actuator can achieve larger angular velocity and higher carrying capacity than those in literature.