A method and device are disclosed for actuating a piezoelectric motor by two driving electrodes by applying periodic control voltages to the driving electrodes. A simplified closed-loop control of the piezoelectric motor is realized by reducing the static friction of a friction contact between a friction element of the piezo-electric motor and an output element to be driven by the friction element without a propulsion of the output element at the same time. In exemplary embodiments, the periodic control voltages are applied with a phase shift to the driving electrodes in a first step of the method, and in a second step of the method, the amplitude ratio of the periodic control voltages is changed with respect to the first step.

A driving device generates a driving signal and outputs the driving signal to a piezoelectric element, the driving signal having a waveform obtained by using, as a first modulated wave, a first low-frequency wave having a frequency of 1 Hz or more and less than 100 Hz, using, as a second modulated wave, a waveform obtained by modulating an amplitude of a second low-frequency wave having a frequency of 100 Hz or more and 300 Hz or less with the first modulated wave, and modulating a high-frequency wave having a frequency of 20 kHz or more and 100 kHz or less with the second modulated wave.

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 piezoelectric device includes a piezoelectric element, a mounting plate, an electronic element including a temperature sensor therein, a base on which the piezoelectric element is mounted with the mounting plate therebetween and on which the electronic element is mounted, and a lid joined to the base and hermetically sealing at least the piezoelectric element and the mounting plate.

Provided is a control apparatus of a vibration-type actuator for generating an elliptical motion of contact portions by a common alternating current including a frequency determining unit for setting a frequency of the alternating current. The frequency determining unit sets the frequency of the alternating current for changing an ellipticity of the elliptical motion, within a frequency range such that ellipticity changing frequency ranges set for the vibrators are overlapped, and the ellipticity changing frequency ranges are set for the vibrators as frequency ranges between an upper limit and a lower limit, such that the lower limit is a maximum resonant frequency at a time of changing the ellipticity, and the upper limit is larger than the lower limit and is a maximum frequency for the relative movement of the driving member.

An ultrasonic motor includes a vibration section having a piezoelectric element configured to generate vibration by receiving a drive voltage, a driven section, a convex section connected to the vibration section and configured to transmit vibration of the vibration section to the driven section, a drive circuit configured to generate the drive voltage, an encoder configured to detect a movement amount of the driven section, a storage section configured to store a specified voltage value, and a determination section configured to receive position information from the encoder when the driven section starts to move and a voltage value at the time of start up from the drive circuit and to determine that least one of the convex section or the driven section is worn out when the voltage value at the time of start up is larger than the specified voltage value.

Information regarding a rotational speed is detected by utilizing a variation in the amplitude at a frequency corresponding to the number of a plurality of protrusions of a vibrating member generated in an S-phase signal detected from a vibration detection electrode of a vibration-type actuator.

A first driving signal is supplied to a first electrode of a vibrating body. A second driving signal is supplied to a second electrode of the vibrating body. A common driving signal is supplied to a common electrode of the vibrating body. A phase of the first driving signal is set changeable with respect to a phase of the common driving signal. A phase of the second driving signal is set changeable with respect to the phase of the common driving signal. Then, it is possible to switch a driving direction of a piezoelectric motor according to which phase of the first driving signal or the second driving signal is varied from the phase of the common driving signal. If the phase is simply changed, a switch is unnecessary. It is possible to reduce a driving circuit in size.

A piezoelectric driving device includes a piezoelectric vibrating body and a driving circuit. The piezoelectric vibrating body includes a contact which comes into contact with a driven member, and a piezoelectric element which generates vibration in accordance with a driving voltage. The driving circuit sets a driving frequency of the driving voltage to a first frequency and starts the driving at the time of initiation from a stopped state, and sets the driving frequency of the driving voltage to a second frequency lower than the first frequency in a driving state after the initiation.

A driving device generates a driving signal and outputs the driving signal to a piezoelectric element, the driving signal having a waveform obtained by using, as a first modulated wave, a first low-frequency wave having a frequency of 1 Hz or more and less than 100 Hz, using, as a second modulated wave, a waveform obtained by modulating an amplitude of a second low-frequency wave having a frequency of 100 Hz or more and 300 Hz or less with the first modulated wave, and modulating a high-frequency wave having a frequency of 20 kHz or more and 100 kHz or less with the second modulated wave.