No abstract

Piezoelectric motors exhibit advantages such as high force density and linear motion with simple and compact configuration compared to electromagnetic motors. Among them, an inchworm mechanism provides high holding force and thrust, and high positioning accuracy. However, the drawback is its complicated structure combining multiple transducers. On the other hand, an ultrasonic linear motor with quadruped stator can achieve the inchworm movement by using a single rectangular plate transducer, which is advantageous for miniaturization. In this study, we propose a novel ultrasonic linear motor that drives a slider rod inside the quadruped stator to realize a compact linear motion system. A prototype was fabricated and an excitation of each vibration mode and a bidirectional drive was confirmed via experiments. Maximum no-load speed of 258 mm s−1 and maximum thrust of 490 mN were obtained with total length of the stator transducer of 20 mm and its weight of 4.9 g.