To develop theoretical instructions for designing the dive of ultrasonic motor(USM),an equivalent electrical model for the USM was studied. Firstly,the vibration equation of the piezoelectric laminated piezoelectric beams excited by electricity was given, which resulted to a six-side equivalent circuit model for the beam's vibration. Then, taking into account the polarization configuration of the stator of the USM, a distributed parameter circuit network mode was derived for the free stator. Focusing on the stator's vibration in the frequency range near the motor's working modal frequency, with addtions, by modeling the dielectric loss and mechanical loss of the stator, a two-side equivalent circuit model was proposed for the stator. Finally, by taking into account the motor's pre-pressure, load and temperature which greatly influenced the characteristic of the
USM, a complete electrical equivalent model was established for the USM. Experiments
were made to validate the models. The results show that the experimental values agree
the simulations from the models well, which indicates that the models are available.
