A lens barrel includes: an electromechanical conversion element; an elastic body having a joining surface, a drive surface, and grooves; a motion member rotating by vibration wave of the drive surface; a rotating ring having a recess part and rotating by rotation of the motion member; a moving ring engaged to the recess part and moving to an optical axis direction by rotation of the rotating ring; and a lens held in the moving ring; wherein the element is made of a material having sodium potassium niobate, potassium niobate, sodium niobate or barium titanate, wherein a value of T/(B+C) is within a range of from 1.3 to 2.8 when: length from the drive surface to a base unit of the groove is defined as T; length from the base unit of the groove to the joining surface is defined as B; and thickness of the element is defined as C.

The invention relates to a piezoelectric motor with bending travelling wave, comprising a rotary shaft (4) connected to a rotor (3), a piezoelectric element (2) attached to a vibrating stator (1), and a decoupling web (5) for attaching the vibrating stator to a mounting (7). The mounting (7) is mechanically connected to a base (9) by means of at least one deformable element (10) and at least one piezoelectric actuator (11), so that the support can be deformed angularly relative to the base in order to rotate the shaft when the vibrating stator is no longer electrically powered. The motor is particularly suitable for applications that require micrometre or nanometre accuracies, for example in positioning tools in industrial processes, precise medical robotics or optical applications.

A method for operating a drive unit having an active element with a resonator and an excitation structure for exciting oscillations in the resonator and thereby driving a passive element. The method includes driving the excitation structure with a driving signal, the driving signal being a periodic signal having driving pulses repeated with an excitation frequency. Depending on a control signal, modifying the driving signal, if the control signal is within a first range, by modifying the excitation frequency or modifying the shape of the driving pulses and, if the control signal is within a second range, repeatedly omitting driving pulses.

A composite motor having high-precision positioning, comprising: a housing (1), a rough positioning assembly, a hollow output shaft (2), a fine positioning assembly, a power switching apparatus and a controller (6). A stepper motor (3) in the rough positioning assembly is responsible for rough positioning of the composite motor, an annular travelling wave ultrasonic motor in the fine positioning assembly is responsible for tail end fine positioning of the composite motor, and the controller (6) implements power output switching between the annular travelling wave ultrasonic motor and the stepper motor (3). The composite motor effectively solves the problem that annular travelling wave ultrasonic motors which operate continuously for a long time have a short service life, and ensures high-precision positioning while also extending motor service life.

A control method of a piezoelectric driving device which includes a vibrator including a piezoelectric element and vibrating by application of a drive signal to the piezoelectric element, a driven unit moving by the vibration of the vibrator, a drive signal generation unit generating the drive signal based on a pulse signal, the control method including: stopping the application of the drive signal to the piezoelectric element at the time when a driving speed of the driven unit is a reference speed, in a case of stopping driving of the driven unit.

A vibration wave motor includes a vibrator, a contact body to be brought into contact with the vibrator, a shaft fixed to the contact body, and a fixing member configured to fix the contact body and the shaft from the shaft side.

A control method for a piezoelectric drive device includes a first step of executing first control to decrease a frequency of a drive voltage applied to a piezoelectric vibrator from a predetermined first frequency while acquiring a pickup voltage representing vibration amplitude of the piezoelectric vibrator, and a second step of executing second control to increase the frequency of the drive voltage applied to the piezoelectric vibrator to a second frequency as a frequency of the drive voltage applied before a second time when the pickup voltage is higher from a first time to the second time and the pickup voltage is lower from the second time to a third time.

A control apparatus to control a vibration motor includes a control unit. The vibration motor includes a vibration body and a contact body contacting the vibration body. The control apparatus applies alternating voltages, generated based on pulse width and frequency of pulse signals, to an electro-mechanical energy conversion element of the vibration motor to cause relative movement between the vibration and contact bodies at a target velocity. The pulse width and the frequency are (i) set such that a first steady velocity exceeds the target velocity, before the relative movement starts, and (ii) changed such that a second steady velocity is less than the first steady velocity, after the relative movement starts, and before an actual velocity at a time of the relative movement exceeds the target velocity. The pulse width or the frequency is controlled such that the relative movement is performed at the target velocity.

A reaction compensation device includes a drive mechanism driving a first movable part with respect to a base, a reaction mass drive mechanism driving a second movable part with respect to the base; and a first relative position sensor measuring a relative position between the first movable part and the base. There is also a second relative position sensor measuring a relative position between the second movable part and the base, a first control system controlling the drive mechanism by taking in a signal outputted from the first relative position sensor as a feedback signal in response to a command value, and a second control system correcting the command value using a correction parameter for adjusting a difference between mass properties of the drive mechanism and reaction mass drive mechanism and for controlling the reaction mass drive mechanism.

The driving apparatus comprises a vibrating body which includes an electro-mechanical energy conversion device, and drives a vibration-wave motor which moves the vibrating body and a driven body relatively to each other. The electro-mechanical energy conversion device has sensor electrodes that output detecting signals corresponding to vibrations of the vibrating body. Based on the detecting signals, the driving apparatus determines a direction in which the vibrating body and the driven body are to be moved relatively to each other.