A method of controlling a piezoelectric motor as a piezoelectric drive device having a vibrator including piezoelectric elements, a rotor as a driven unit that moves at a target speed by vibration of the vibrator, and drive signal generation units that generate drive signals and output the drive signals to the piezoelectric elements, includes intermittently outputting the drive signals to the piezoelectric elements by the drive signal generation units, wherein a time when output of the drive signals is stopped is shorter than a time from when output of the drive signal is stopped to stoppage of the vibration.

Provided is a method for controlling an ultrasonic motor to reduce deterioration of automatic tracking performance, and a surveying instrument for the same. The present invention provides a method for controlling an ultrasonic motor in a surveying instrument including a rotary shaft, an ultrasonic motor that drives a rotary shaft, a tracking unit that includes a light emitting unit and a light receiving unit and tracks a target, and a clock signal oscillation unit that outputs a clock signal, wherein at the time of low-speed rotation of the ultrasonic motor, based on the clock signal, a ratio of an acceleration period in which a drive signal is applied and a deceleration period in which the drive signal is stopped in a drive cycle of the drive signal of the ultrasonic motor is set, and the light emitting unit is made to emit light in the deceleration period.

A simple rugged motor has a stator and a rotor formed by stacked silicon steel sheets operates by having a plurality of major and minor coil windings of the stator individually electrified under signals of a control unit, so as to steadily drive a rotor thereof. The simple rugged motor further has an orbit coupling balance assembly engaging an orbiting scroll for a corresponding fixed scroll disposed in a compression chamber to orbit for air compression, so as to form a scroll compressor. Or the simple rugged motor has a coupling assembly engaging a female screw compressor rotor to compress the air by a rotatable male screw compressor rotor disposed in a compression chamber, so as to form a screw compressor.

A driving apparatus of a vibration-type actuator includes a driving circuit configured to drive a vibration unit including a plurality of vibrators, a detection unit configured to detect a sum of power consumption consumed by the plurality of vibrators, and a driving frequency setting unit configured to set a driving frequency within a frequency range depending on the sum of power consumption detected by the detection unit.

Provided is a vibration wave motor including: 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 controller is capable of improving position detection accuracy during the stopping of an actuator, and controlling the actuator with high stability and quick responsiveness during driving. A first position signal corresponding to an amount of relative movement between the actuator and a driven element is output to a filter, and the filter outputs a second position signal generated by attenuating signal components having frequencies except a specific frequency band. Driving and stopping of the actuator are controlled according to the second position signal. As the specific frequency band, a first frequency band is set in the filter during the driving of the actuator, and a second frequency band is set in the filter during the stopping of the actuator. The first frequency band and the second frequency band both include 0 Hz, and the second frequency band is narrower than the first frequency band.

A control method for a piezoelectric drive device includes a piezoelectric vibrator having a vibrating portion and a distal end portion coupled to the vibrating portion, in which the distal end portion makes elliptic motion by a stretching vibration and a flexural vibration of the vibrating portion, a driven member driven by the elliptic motion of the distal end portion, and a drive signal generation circuit outputting a stretching vibration drive signal that generates the stretching vibration and a flexural vibration drive signal that generates the flexural vibration in the piezoelectric vibrator, and the method includes, when the driven member is stopped, superimposing and outputting a modulation signal for amplitude modification on the stretching vibration drive signal by the drive signal generation circuit.

A piezoelectric drive device has a first piezoelectric vibrator and a second piezoelectric vibrator each include a vibrating portion and a distal end portion in which the distal end portion make elliptic motion by stretching vibration and flexural vibration of the vibrating portion, a driven member driven by the elliptic motion of the distal end portion, a drive signal generation circuit that outputs stretching vibration drive signals to the first piezoelectric vibrator and the second piezoelectric vibrator, a first boosting circuit provided between the first piezoelectric vibrator and the drive signal generation circuit, a second boosting circuit provided between the second piezoelectric vibrator and the drive signal generation circuit, and a control circuit that controls boosting amounts of the stretching vibration drive signals.

A vibration motor controller configured to cause a vibrating member in which a vibration is excited based on two frequency signals having a phase difference to move relatively to a contact member, the vibration motor controller including: a memory configured to store a speed characteristic of the vibrating member with respect to a frequency of the two frequency signals; a controller configured to control a speed of the vibrating member by changing the frequency and/or a phase difference of the two frequency signals; a detector configured to detect the speed; and a changing unit configured to acquire change amount and change direction of the speed characteristic based on comparison between the speed detected by the detector and the speed characteristic stored in the memory, and change an activation frequency being a start point of control conducted by the controller based on the change amount and the change direction.

A piezoelectric element that can decrease the output voltage for detection relative to the input voltage for driving without requiring a step-down circuit between a detection phase electrode and a phase comparator and an oscillatory wave motor including the piezoelectric element are provided. A piezoelectric element includes a piezoelectric material having a first surface and a second surface, a common electrode disposed on the first surface, and a drive phase electrode and a detection phase electrode disposed on the second surface. An absolute value d(1) of a piezoelectric constant of the piezoelectric material in a portion (1) sandwiched between the drive phase electrode and the common electrode and an absolute value d(2) of a piezoelectric constant of the piezoelectric material in a portion (2) sandwiched between the detection phase electrode and the common electrode satisfy d(2)<d(1). An oscillatory wave motor includes this piezoelectric element.