A control method for reducing vibration of a second casing of a mobile terminal includes: mounting an additional vibrator in a mounting area on the second casing, and measuring vibration responses in the mounting area under first and second preset conditions; calculating system transfer functions of the additional vibrator and a driving system formed by a first casing and an exciter; providing a signal processing unit; adjusting the value of the transfer function of the signal processing unit such that a vibration response in the mounting area under a third preset condition is at zero, and calculating the value of the transfer function H3(S) of the signal processing unit; and setting H3(S) as a preset transfer function of the signal processing unit. The present disclosure can counteract the vibration of the second casing induced by the driving system, thereby improving user experience.

An experimentation apparatus tests for heat produced by cavitation. The experimentation apparatus includes a heating chamber, a quantity of heavy water, a piezo-disk antenna, a target foil, a transmission line, a signal generator, a control unit, and at least one sensor. The heavy water is retained within the heating chamber and is agitated by the piezo-disk antenna to form cavitation bubbles. These cavitation bubbles impact the target foil in order to potentially produce deuteron combination events that could consequently produce heat. The signal generator sends an electrical signal along a transmission line to the piezo-disk antenna in order to dictate how the piezo-disk antenna vibrates within the heavy water. The control unit is used to manage the operational functionalities of the experimentation apparatus such as instructing the signal generator to adjust the frequency of the electrical signal. The at least one sensor collects experimentation data within the heating chamber.

A vibration type actuator including vibrating elements and a contact element that is brought into contact with each other in a first direction. The vibration of the vibrating elements includes vibration in a first vibration mode in the first direction and vibration in a second vibration mode in a second direction intersecting the first direction. In the vibrating elements, a minimum value of a resonance frequency in the second vibration mode is greater than or equal to a maximum value of a resonance frequency in the first vibration mode, and a ratio of a difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second mode is less than or equal to a predetermined value.

A vibration type drive device capable of maintaining stable drive performance and controllability. The vibration type drive device comprises a vibration type actuator comprising a vibrator and a contact body, and a drive control device. The drive control device applies two-phase alternating current voltages to the energy conversion element of the vibrator by a drive portion, converts a control amount of feedback control based on the relative position/speed into a phase difference between the two-phase alternating current voltages, and outputs the phase difference to the drive portion by using, for the relative movement, a phase difference of a first or second quadrant at a coordinate (in a first direction) and a phase difference of a third or fourth quadrant (in a second direction), wherein vertical axis: SIN , horizontal axis: COS , : phase difference.

A display apparatus includes: a display panel configured to display an image, a vibration plate on a first surface of the display panel, a first structure on a second surface of the vibration plate, the first structure being configured to support the display panel, a first vibration-generating device configured to vibrate the vibration plate, and a separation part connected to the vibration plate and configured to separate a first space, facing a first surface opposite to the second surface of the vibration plate, from a second space facing the second surface of the vibration plate.

A vibration actuator includes a vibration element including a piezoelectric element as an electromechanical energy conversion element and an elastic body which is joined to the piezoelectric element, and a driven element which is brought into pressure contact with the elastic body. Driving vibration is excited in the vibration element by applying a drive signal to the piezoelectric element, whereby the vibration element and the driven element are moved relative to each other. The driving vibration is a vibration in which at least n-th-order vibration and 2n-th-order vibration are combined, n being a natural number.

A piezoelectric device drive circuit applies a drive signal to a piezoelectric device. An H-bridge circuit includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal, the first output terminal and the second output terminal being connected to the piezoelectric device. A resistor is connected between the piezoelectric device and the first output terminal. A differential amplifier circuit receives, as an input, a voltage across the resistor. An inverting circuit has an input terminal connected to an output terminal of the differential amplifier circuit. A comparator has an input terminal connected to an input terminal of the inverting circuit, and an output terminal connected to the first input terminal. A comparator has an input terminal connected to an output terminal of the inverting circuit, and an output terminal connected to the second input terminal.

An actuator device manufacturing method includes: a preparation step of preparing an actuator device including a support portion, a movable portion, a connection portion, and a metal member disposed such that a stress acts on the metal member when the movable portion oscillates; an oscillation step of oscillating the movable portion for a predetermined time; an acquisition step of acquiring a parameter related to a viscous resistance in a vibration of the movable portion; and a determination step of determining that the actuator device is qualified, when a difference between the parameter acquired in the acquisition step and a reference value corresponding to the parameter at a start of the oscillation step is a predetermined value or more in a direction in which the viscous resistance decreases, and determining that the actuator device is disqualified, when the difference is less than the predetermined value.

A vibration drive device that is capable of preventing the controllability from becoming unstable when the speed control is switched between frequency control and pulse width control. A controller controls driving of a vibration actuator by applying an alternating voltage to an electromechanical energy conversion element. A switching pulse is generated by switching a DC voltage. A maximum duty ratio of the switching pulse is determined based on a driving condition of the vibration actuator. The driving of the vibration actuator is controlled by switching between frequency control and pulse width control. A gain for frequency control and a gain for pulse width control are set according to the maximum duty ratio so as to prevent electric power or electric current from exceeding an electric power limit or an electric current limit, set in advance.

A vibration type actuator control apparatus is configured to control driving of a vibration type actuator configured to move a moving body that is one of the vibrator and a contact body that contacts a vibrator. The vibration type actuator includes the vibrator in which a vibration is excited when a two-phase drive signal having a phase difference is applied to an electro-mechanical energy conversion element. The vibration type actuator control apparatus includes a drive signal generator configured to generate the two-phase drive signal. The drive signal generator changes a phase difference of the two-phase drive signal from an initial phase difference when the moving body is moved from a stopped state. The initial phase difference is determined based on a phase difference shift indicative of a shift from a phase difference set so as to stop the moving body.