Electric motors are widely used in all kinds of engineering applications nowadays. Conventional motors are driven by electro-magnetic effect. In the past decade, a new breed of motor has evolved and attracted great attention of the industry. This new actuator is driven by piezo-ceramics at an ultrasonic frequency. They are known as ultrasonic motors (USM). The advantages of ultrasonic motors include compact size, hollow structure, quick response and remarkably high torque, low speed performance. Typical applications of ultrasonic motors are driving the auto zoom lenses in photo equipment and other magnetic field sensitive devices. In this study, a new principle is used to actuate a rotary motor using anisotropic piezoelectric composite laminate. By taking advantage of material anisotrop...[ Read more ]

Electric motors are widely used in all kinds of engineering applications nowadays. Conventional motors are driven by electro-magnetic effect. In the past decade, a new breed of motor has evolved and attracted great attention of the industry. This new actuator is driven by piezo-ceramics at an ultrasonic frequency. They are known as ultrasonic motors (USM). The advantages of ultrasonic motors include compact size, hollow structure, quick response and remarkably high torque, low speed performance. Typical applications of ultrasonic motors are driving the auto zoom lenses in photo equipment and other magnetic field sensitive devices. In this study, a new principle is used to actuate a rotary motor using anisotropic piezoelectric composite laminate. By taking advantage of material anisotropy, a piezoelectric laminated beam can induce torsional motion from in-plane strain actuation. With this structural coupling, a rotary actuator similar to ultrasonic motors can be implemented. In addition to analytical formulation and conceptual design, a prototype has been fabricated in the past. Actual motion was observed in the laboratory to verify the proposed actuation principle. Base on this prototype, several smaller ultrasonic motors have been fabricated to demonstrate the ability for miniaturization. These mini-motors were characterized for rotating speed and torque using self-developed test rig for comparison with commercial mini-electric motors. A finite element code was also used to model the proposed device. The dynamic structural coupling behaviors of anisotropic piezoelectric laminate were studied to understand the actual driving principal of the proposed ultrasonic motor. The present research has demonstrated a live model for applying smart material systems to actual devices with a better performance over traditional devices.