Performance of Non-Contact Linear Actuators Driven by Surface Acoustic Waves*

A new kind of non-contact linear actuator (motor) driven by surface acoustic waves (SAWs) is presented, in which the stators are made from SAW delay lines using 128° YX-LiNbO₃ substrates. A fluid layer is introduced between the slider and the stator of the actuator, and the slider is a circular aluminum disk suspended on the surface of the liquid (water) layer. As the SAW is excited on the stator, the SAW is converted to a leaky wave in the interface of the stator and the liquid, and then propagates into the liquid. Owing to the nonlinear effect of wave propagation, acoustic streaming is generated, which pushes the slider to move. By the experiments, the relations between the slider velocity and the experimental parameters, such as the exciting voltage of the SAWs, the thickness and the kinematic viscosity of the liquid layer, are obtained.