Provided is a method for controlling an ultrasonic motor to reduce noise sounding during low-speed rotation in a surveying instrument adopting the ultrasonic motor for a rotary shaft, and a surveying instrument for the same. In a method for controlling an ultrasonic motor according to an aspect of the present invention, in a low-speed rotation range of an ultrasonic motor, a ratio of an acceleration period as a time of application of the drive signal in a control cycle is controlled, and a time to start the acceleration period is randomly shifted for each control cycle. In a method for controlling an ultrasonic motor according to another aspect, a time to start the acceleration period is regularly shifted for each control cycle. In a method for controlling an ultrasonic motor according to still another aspect, second-half acceleration control and first-half acceleration control are alternately repeated.

Provided is a method for controlling an ultrasonic motor provided at a rotary shaft of a surveying instrument to meet requirements for a rotation speed and a plurality of operation modes, and a surveying instrument for the same. In the present invention, the ultrasonic motor is controlled by a first signal having a square wave in a range of rotation speed of the rotary shaft from zero to a first speed, controlled by a second signal in which rises or falls of the square wave are sloped in a range from the first speed to a second speed, controlled by a third signal in which rises and falls of the square wave are sloped in a range from the second speed to a third speed, and controlled by a fourth signal in which the drive signal is continuously applied in a range higher than the third speed.

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.

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 piezoelectric element having an improved piezoelectric constant is provided, and a liquid discharge head, an ultrasonic motor, and a dust removing device, each of which uses the above piezoelectric element, are also provided. A piezoelectric element at least includes a pair of electrodes and a piezoelectric material provided in contact with the pair of electrodes, the piezoelectric material is formed of an aggregate of crystal grains containing barium titanate as a primary component, and among the crystal grains of the aggregate, crystal grains at least in contact with the electrodes have dislocation layers in the grains. A liquid discharge head, an ultrasonic motor, and a dust removing device each use the above piezoelectric element.

A vibration wave motor includes a driven body, a vibrator including an annular vibration plate and an annular piezoelectric element, and a vibration damping member, which are arranged in sequence, wherein the vibration plate has, on a side facing the driven body, radially extending groove portions at X places, and, when center depths of the groove portions at X places are sequentially denoted by D1 to DX in a circumferential direction, D1 to DX vary along a curve obtained by superposing one or more sine waves, and wherein the vibration plate is locally supported by the vibration damping member in some or all antinode portions of a standing wave occurring when the vibration wave motor is driven.

The present invention provides a piezoelectric material not containing lead and potassium, having a high relative density, a high Curie temperature, and a high mechanical quality factor, and exhibiting good piezoelectricity. The piezoelectric material contains 0.04 percent by mole or more and 2.00 percent by mole or less of Cu relative to 1 mol of metal oxide represented by General formula (1) below.
((Na.sub.1-zLi.sub.z).sub.xBa.sub.1-y)(Nb.sub.yTi.sub.1-y)O.sub.3 (in Formula, 0.70≦x≦0.99, 0.75≦y≦0.99, and 0<z<0.15, and x<y)  General formula (1)

A drive device for a vibration actuator, which makes it possible to perform low-speed and stable driving and expand a dynamic range of driving speed. A first switching circuit and a second switching circuit apply a first drive signal and a second drive signal for exciting vibration, to an electromechanical energy conversion element of a vibrating body. A position detection sensor acquires information on a relative position between the vibrating body and a driven body in pressure contact with each other. An MPU switches the first and second drive signal to a third drive signal and a fourth drive signal, respectively, based on the acquired information, to thereby change a position at which a largest one of peaks of amplitude of vibration excited in the vibrating body is formed.

A vibration type actuator includes a vibration body, having an annular elastic body and an electro-mechanical energy conversion element, and includes a contact body having an annular shape. The contact body contacts the vibration body and relatively moves with regard to the vibration body. The contact body includes a base portion, a supporting portion that extends in an annular shape from the base portion in a radial direction of the contact body, and a friction member that is provided to the supporting portion, is a member different from the supporting portion, and is in contact with the vibration body. The friction member is connected to the supporting portion by a first surface extending along a central axis direction of the contact body and an annular second surface extending in the radial direction. The first surface includes a portion inclined with respect to the direction of the contact body central axis.

A vibration-type drive apparatus which increases productivity and also prevents undesired vibration from occurring during operation. The vibration-type drive apparatus has an elastic body, a vibrating body having an electro-mechanical energy conversion element mounted on the elastic body, a driven body that is brought into pressure contact with the vibrating body, and a pressurizing member that brings the driven body into pressure contact with the vibrating body. Relative positions of the vibrating body and the driven body change due to vibrations excited in the vibrating body. The pressurizing member has a positioning portion, and the driven body has a fitting-receiving portion that is to be fitted onto the positioning portion. During operation, the positioning portion and the fitting-receiving portion are not in contact with each other.