Study on the axial/radial coupling non-contact ultrasonic piezoelectric actuator with a spherical rotor

The axial/radial coupling non-contact ultrasonic piezoelectric actuator with a spherical rotor based on inverse piezoelectric effect is proposed. It is made up of an axial suspension device and a radial suspension device, both of them can form a travelling wave, which provides levitation force and driving force for the spherical rotor. As the axial and radial levitation device have different working mode combination, which makes the induced sound field have different coupling strength of levitation and rotary driving force. Then, the spherical rotor can acquire different levitation effect and rotary speeds; it is easy to get control of the state of the spherical rotor. The prototype is manufactured and the stator vibration parameters, levitation and driving characteristics of the axial levitation device are obtained by test. The experimental results primarily show that the axial levitation device successfully levitates and drives the spherical rotor.