Characteristics of a piezoelectric miniature motor

Abstract

The performance of a piezoelectric inchworm motor with a diameter of 4 mm has been evaluated on a miniature scale. The experiments have shown that some of the desired characteristics for a miniature motor such as a high output torque and linear control of rotational velocity with frequency can be achieved using a simple construction. The experimentally measured maximum output torque of 1.4 mN μm is one of the highest presented for a motor of this size. To prevent electrode failure in this first miniature prototype the maximum speed was limited to 4.2 rpm. The most critical parameter for motor performance is height deviations between piezoceramic elements which therefore should be minimised. Further, results show a reasonable agreement with a previously derived analytical model. An optimised motor design is expected to have maximum output torque and speed values as high as 10 mN μm and 120 rpm.