Abstract: A piezoelectric motor comprising a vibratory element is configured to move a first driven element by vibrations generated by the vibratory element. A second driven element is brought into frictional contact with the first driven element to form a multistage piezoelectric drive system. Alternatively, a selected contacting portion on a support for the first driven element is provided for drivingly engaging the second driven element. The system is configured to also move the second driven element by vibrations generated by the vibratory element, these vibrations being transmitted from the vibratory element into the first driven element and possibly also into the support for the first driven element. The system is preferably configured to move the first and second driven elements independently from each other using only electric signals that are applied to the same one vibratory element.

Abstract: A piezoelectric system has a piezoelectric motor (20) driving a driven element (22) so as to move the driven element (822) in response to an electric signal (25). The motor (20) has at least a first optimal operating frequency at which the motor (20) moves the driven element (22) an amount that meets predetermined criteria. The motor (20) and driven element (22) have a desired performance criteria when operated at that first operating frequency. A plurality of concatenated sinusoidal sweeping frequencies are repeatedly supplied to the piezoelectric motor (20) with at least one of the sweeping frequencies being sufficiently close to the first operating frequency to cause detectable motion of the driven element (22). The frequencies are varied in response to movement of at least one of the motor (20) and the driven element (22) to produce an average performance of the motor (20) and driven element (22) for a time corresponding to the time for one sweep of frequencies.

Abstract: A single piezoelectric is excited at a first frequency to cause two vibration modes in a resonator producing a first elliptical motion in a first direction at a selected contacting portion of the resonator that is placed in frictional engagement with a driven element to move the driven element in a first direction. A second frequency excites the same piezoelectric to cause two vibration modes of the resonator producing a second elliptical motion in a second direction at the selected contacting portion to move the driven element in a second direction. The piezoelectric is preloaded in compression by the resonator. Walls of the resonator are stressed past their yield point to maintain the preload. Specially shaped ends on the piezoelectric help preloading. The piezoelectric can send or receive vibratory signals through the driven element to or from sensors to determine the position of the driven element relative to the piezoelectric element or resonator.

Abstract: A single piezoelectric is excited at a first frequency to cause two vibration modes in a resonator producing a first elliptical motion in a first direction at a selected contacting portion of the resonator that is placed in frictional engagement with a driven element to move the driven element in a first direction. A second frequency excites the same piezoelectric to cause two vibration modes of the resonator producing a second elliptical motion in a second direction at the selected contacting portion to move the driven element in a second direction. The piezoelectric is preloaded in compression by the resonator. Walls of the resonator are stressed past their yield point to maintain the preload. Specially shaped ends on the piezoelectric help preloading. The piezoelectric can send or receive vibratory signals through the driven element to or from sensors to determine the position of the driven element relative to the piezoelectric element or resonator.

Abstract: A single piezoelectric is excited at a first frequency to cause two vibration modes in a resonator producing a first elliptical motion in a first direction at a selected contacting portion of the resonator that is placed in frictional engagement with a driven element to move the driven element in a first direction. A second frequency excites the same piezoelectric to cause two vibration modes of the resonator producing a second elliptical motion in a second direction at the selected contacting portion to move the driven element in a second direction. The piezoelectric is preloaded in compression by the resonator. Walls of the resonator are stressed past their yield point to maintain the preload. Specially shaped ends on the piezoelectric help preloading. The piezoelectric can send or receive vibratory signals through the driven element to or from sensors to determine the position of the driven element relative to the piezoelectric element or resonator.

Abstract: A single piezoelectric is excited at a first frequency to cause two vibration modes in a resonator producing a first elliptical motion in a first direction at a selected contacting portion of the resonator that is placed in frictional engagement with a driven element to move the driven element in a first direction. A second frequency excites the same piezoelectric to cause two vibration modes of the resonator producing a second elliptical motion in a second direction at the selected contacting portion to move the driven element in a second direction. The piezoelectric is preloaded in compression by the resonator. Walls of the resonator are stressed past their yield point to maintain the preload. Specially shaped ends on the piezoelectric help preloading. The piezoelectric can send or receive vibratory signals through the driven element to or from sensors to determine the position of the driven element relative to the piezoelectric element or resonator.