A traveling-wave linear piezoelectric actuator with enclosed piezoelectric elements-the "scream" actuator

A 1.8 cc silent bidirectional traveling-wave self-moving linear microactuator is shown to be capable of generating a sliding velocity of 0.22 m/s and sliding force of 1.1 N. The generation of a radial traveling wave about the circumference of the actuator, akin to a ring, is shown to exist despite the unusual shape, and the presence of traveling wave motion along the output face is also shown to exist By using short-time sinusoidal signals, slider displacements as small as 82 nm were obtained from the actuator, and by using DC input, displacements of up to ±107 nm were obtained, suggesting a way to obtain sub-nanometer positioning accuracy over arbitrary sliding distances. By reversing the phase between the paired driving signals, the direction of motion was reversed at up to 300 Hz; the slider displacement and velocity was found to be inversely proportional to the phase reversal rate, and the slider's peak velocity and maximum thrust force were directly proportional to the phase between the driving signals. The output force and velocity of the actuator was fairly insensitive to the input frequency, giving measurable motion between 1315 and 141.5 kHz, but was sensitive to the input voltage, requiring at least 38 V input for operation, and was approximately quadratically-dependent on the applied preload centered about 2.25 N.