Numerical analysis of the symmetric hybrid transducer ultrasonic motor

In this paper, operation of a symmetric hybrid transducer ultrasonic motor with output produced by two rotors connected together via a driveshaft is numerically analyzed and compared with the traditional asymmetric hybrid transducer motor design that produces its output from only one rotor. A one-dimensional finite element model for torsional vibration in the stator and a Coulomb friction model for rotor/stator contact associated with the longitudinal vibration of the motor are introduced. The calculation results demonstrate that the symmetric design is capable of performance comparable with the traditional asymmetric design when an optimum static spring force in the rotor/stator contact interface is applied during operation.