A ring-shaped, linear piezoelectric ultrasonic motor operating in E₀₁ mode

Linear piezoelectric ultrasonic motors based on multimodal coupling are widely used for generating precision actuations; however, multimodal decoupling often occurs when environment temperature changes, which may result in actuation failure. In this work, a miniature, ring-shaped, linear piezoelectric ultrasonic motor operating in a single, in-plane E₀₁ mode (zero node line along the circumference and one node line along the diameter direction) is proposed. Experimental results show that it can produce a maximum driving force of 2.7 N, a no-load moving speed of ∼56 mm/s, and a high positioning resolution of 0.1 μm in open-loop control. Advantages of simple structure, controllable micrometer-scale displacement, and large bidirectional working stroke indicate that the proposed linear motor has great potential for industrial applications, especially for precise actuations.