An ultrasonic linear motor using traveling waves of twin ridge

An ultrasonic linear motor using ridge‐mode traveling waves on a substrate is proposed for precision positioning. In our experiments, two parallel ridges are machined on an alumina ceramic substrate with the spacing of 19 mm. The width, height, and length of the ridge are 3 mm, 9 mm, and 186 mm, respectively. Two piezoelectric elements, 19 mm in length and 5×5 mm2 in cross section, were installed at the position of 15 mm from each end of the ridge, and excited at 87.136 kHz in their fundamental longitudinal mode to stimulate the fundamental ridge mode. Elliptical particle motions are formed, due to traveling waves along the ridge waveguides by the phased drive of the two transducers. An alumina ceramic slider pressed to the two waveguides is moved at 13 mm/s in the opposite direction to the traveling wave through the friction forces. The moving direction can be switched by changing the propagation direction of the traveling wave. The detailed characteristics are experimentally studied.