Characteristics and stability mechanism of non-contact ultrasonic motor with a longitudinal transducer

Area of Science:

• Mechanical Engineering
• Acoustics
• Smart Drive Actuators

Background:

• Ultrasonic motors (USMs) offer potential in space exploration, optics, and biomedicine but face challenges like complex control, friction, and structural limitations.
• Existing USM designs are hindered by severe friction and wear between stator and rotor components, impacting performance and commercial viability.

Purpose of the Study:

• To present a non-contact ultrasonic motor utilizing near-field acoustic levitation to overcome traditional USM limitations.
• To simplify the motor structure, eliminate friction and wear, and improve overall motor performance through acoustic levitation.

Main Methods:

• Developed a theoretical model based on Navier-Stokes equations to analyze the motor's characteristics and stability mechanisms.
• Designed and manufactured a prototype ultrasonic motor incorporating a longitudinal transducer and acoustic levitation.
• Conducted levitation force and restoring force experiments to validate the motor's performance.

Main Results:

• Demonstrated that acoustic levitation effectively separates stator and rotor, eliminating friction and wear during operation.
• Observed that rotational speed increases with driving voltage, with a prototype achieving 30 rpm at 1430 V.
• Found that rotor surface grooves enhance restoring force, reaching 8.5 mN at 1430 V.

Conclusions:

• The proposed non-contact ultrasonic motor design simplifies structure and enhances performance by leveraging acoustic levitation.
• The study validates the motor's operational principles and stability, paving the way for simplified and improved ultrasonic motor designs.
• This research offers a new direction for ultrasonic motor development, promoting applications in automated industries.