In this paper, a new hybrid piezoelectric motor was developed. A range of degeneracy was found to obtain multiple
choice of resonance frequency by adjusting the length of the elastic blocks neighboring to the longitudinal and
torsional vibrators. A template was implemented in between the longitudinal and torsional vibrators to decrease
the mutual vibration effect that effectively makes the calculated and actual driving frequency nearly close. Such
configuration was instrumental to preserve the expected performance and reduce the trial-and-error design overhaul
process of the elastic blocks. Moreover, a dual hybrid motor was easily formed by butting each stator of the
two hybrid motors together with a rotor in the middle. Case studies of both single and dual hybrid motors are
presented with both simulation and experimental results to demonstrate the structure design and the degeneracy
approach. Besides the convenience of structurally combining two single hybrid motors to enhance the output, it
was interesting to find out whether the proposed dual hybrid motor can significantly increase either the speed or
torque by using different phase control methods. Therefore, using the dual hybrid motor provides a great advantage
by providing an option for pursuing higher speed or larger torque output for certain applications.
