A vibration actuator that is capable of reducing difference of vibration velocities when a contact member is driven using a plurality of vibrators includes a vibrator device and the contact member, which moves relative to the vibrator device. The vibrator device includes the plurality of vibrators, which are connected in series, and a plurality of inductors, which are connected in parallel to the respective vibrators.

A vibration driving device includes a vibration actuator including a vibrating body and a contact body, the vibrating body including an elastic body and an electromechanical energy conversion element, the contact body being in contact with the vibrating body and movable relatively to the vibrating body; and a control device including a signal generating circuit and a boosting circuit, the boosting circuit including an air-core transformer electrically connected to the signal generating circuit. The vibration actuator is configured to receive a signal output by the control device.

A vibration drive device that is capable of preventing instability when the speed control is switched between frequency control and pulse width control includes a controller that 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 piezoelectric motor includes: a stator having an elastic body, a piezoelectric element and a sliding member adhesively attached to the elastic body; a rotor having an annular member, which includes a disc spring portion and a basic body portion in contact with the sliding member, and a fixture portion to which the annular member is fixed; and a shaft that rotates with the rotor, wherein the disc spring portion of the annular member is fixed to the fixture portion which is fixed to the shaft.

A drive control device 100, which controls driving of a vibration type actuator 200 including a vibrator 214 that includes a piezoelectric element 203, and a rotor 207, includes amplifier circuits 11 and 12 amplifying a power supply voltage to generate a drive voltage to be applied to the piezoelectric element 203, and a microcomputer unit 1. The microcomputer unit 1 performs a control to increase the amplitude of the drive voltage to perform acceleration from when the vibration type actuator 200 is started to when a target speed of the rotor 207 is reached, decrease the frequency of the drive voltage without changing the amplitude of the drive voltage when power supplied to the piezoelectric element 203 exceeds a first power limit P-Lim.sub.1, and increase the amplitude of the drive voltage when the power falls below a second power limit P-Lim.sub.2 during an operation of decreasing the frequency.

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 compact and robust microelectromechanical reflector system that comprises a support, a reflector, a peripheral edge of the reflector including edge points, and suspenders including piezoelectric actuators and suspending the reflector from the support. Two pairs of suspenders are fixed from two fixing points to the support such that in each pair of suspenders, first ends of a pair of suspenders are fixed to a fixing point common to the pair. A first axis of rotation is aligned to a line running though the two fixing points, and divides the reflector to a first reflector part and a second reflector part. In each pair of suspenders, a second end of one suspender is coupled to the first reflector part and a second end of the other suspender is coupled to the second reflector part.

An embodiment of a harvester apparatus comprising two or more charge pump stages may include at least a first charge pump stage to receive an alternating current source, and a second charge pump stage coupled to the first charge pump stage.

A vibration actuator that is capable of reducing differences in vibration phase and vibration amplitude without rising a voltage of a drive circuit when driving a contact member using a plurality of vibrators connected in series. A vibration actuator includes a vibrator device and a contact member that moves relative to the vibrator device. The vibrator device includes transformers of which primary coils are connected in series, and vibrators that are respectively connected in parallel to secondary coils of the transformers.

There is provided a control method for a piezoelectric driving device including a vibrating body configured to vibrate when a driving signal including a periodic signal is applied to a piezoelectric element for driving, a section to be driven that is driven by the vibration of the vibrating body, and a driving-signal generating section configured to generate the driving signal using a pulse signal generated based on a target pulse duty ratio. The driving-signal generating section detects voltage amplitude generated in the piezoelectric element for driving and generates the target pulse duty ratio based on the voltage amplitude. The driving signal includes an intermittent signal formed by an output period in which the periodic signal is output and a suspension period in which the output of the periodic signal is suspended. The driving-signal generating section detects the output-period voltage amplitude and does not detect the suspension-period voltage amplitude.