Abstract: The invention provides a driving method and driving device for a standing-wave-type ultrasonic actuator which can prevent falling of and eliminate unstable motion of a driven body during activation, and which can shorten the time for the driven body to stop moving when driving is to be stopped. In the driving method for a standing-wave-type ultrasonic actuator, by generating a longitudinal vibration and a flexural vibration in an ultrasonic vibrator, a substantially elliptical vibration is produced at a friction-contact member of the ultrasonic vibrator, and with a frictional force of the elliptical vibration serving as a propulsive force, the ultrasonic vibrator and a driven body in contact with the ultrasonic vibrator are made to move relative to each other. The longitudinal vibration is excited at activation time, and the flexural vibration is excited thereafter.

Abstract: An ultrasonic motor includes a stator that includes a comb body with a plurality of circumferentially-arranged comb-like projections and a piezoelectric body integrally mounted on the comb body, a rotor rotatable with respect to the stator, the rotor having a contact surface that establishes pressure contact with the stator, and a driving circuit configured to apply a radio frequency voltage for driving the piezoelectric body to the piezoelectric body. The driving circuit includes a voltage generating unit configured to generate a first radio frequency voltage of which a frequency is randomly varied during a predetermined time period after start-up of the ultrasonic motor.

Abstract: An ultrasonic motor that is capable of stable driving by preventing uneven rotation of a driven body and maintaining the drive efficiency is provided. The ultrasonic motor includes a plurality of ultrasonic transducers including alternately stacked first piezoelectric elements and second piezoelectric elements, and a control unit for applying the same two-phase driving AC voltages to the plurality of ultrasonic transducers. The ultrasonic motor simultaneously generates longitudinal vibration and flexural vibration at the ultrasonic transducers to generate substantially elliptic vibration at output ends of the ultrasonic transducers and relatively moves the ultrasonic transducers and a driven body in contact with the ultrasonic transducers.

Abstract: A piezoelectric actuator system with a position detection function includes an immovable base, a piezoelectric material, a drive shaft, and a movable part. The immovable base has a driving circuit for providing a driving voltage. The piezoelectric material is fixed on the immovable base and electrically coupled to the driving circuit. A length of the piezoelectric material is controlled by the driving voltage. The drive shaft is fixed on the piezoelectric material and has at least two conductive parts having impedance materials. The movable part is disposed on the drive shaft, and a spacer made of a conductive material is installed at its bottom. The two conductive parts are electrically coupled to the spacer, so as to form a conduction path. The driving circuit detects an impedance of the conduction path to determine a position of the movable part.

Abstract: The piezoelectric actuator drive control device has a controller, and executes an initialization process including an optimum phase difference acquisition process P1 and a phase difference inversion detection process P4 at a predetermined frequency. As a result, the optimum phase difference is updated each time the optimum phase difference acquisition process P1 runs to account for wear or temperature change from continuous operation. Furthermore, even if the phase difference between the drive signal and detection signal inverts during a drive frequency sweep due to variation in the vibration characteristic of the piezoelectric actuator, the phase difference inversion frequency and clamping frequency are reset each time the phase difference inversion detection process P4 is executed, thus preventing phase difference feedback control errors.

Abstract: Transducers employing electroactive polymer films are disclosed.

Abstract: A piezoelectric motor (PEM) is driven with loosely coupled inductors 24 and switching amplifier having a pulse width modulator 18, gate driver circuit 21 and two pairs of power mosfets 210, 212 and 220, 222. Energy stored in the PEM at the end of one cycle is transferred to a capacitor 202 for use in a subsequent cycle.

Abstract: A vibration wave driven apparatus capable of preventing a resonance frequency of a vibrator from being shifted to a frequency side higher than a fixed drive frequency of the vibrator during the execution of phase difference control or voltage control. Driving signals are supplied from a control apparatus to a vibration-type actuator having a piezoelectric element that functions as an electromechanical energy conversion element. To control the drive of the vibration-type actuator, either a phase difference between the driving signals or a voltage of the driving signals is changed. When either the phase difference or the driving signal voltage is changed, the frequency of the driving signals is set to a predetermined frequency higher than the frequency for use when neither the phase difference nor the driving signal voltage is changed.

Abstract: A surgical instrument includes a transducer configured to produce vibrations along a longitudinal axis at a predetermined frequency. An end effector is adapted to couple to the transducer and extends along the longitudinal axis. The end effector includes a body having a proximal end and a distal end. The distal end is movable relative to the longitudinal axis by the vibrations produced by the transducer. A drive module is coupled to the transducer to generate a modulated drive signal. The distal end of the end effector is movable in response to the vibrations produced by the transducer in response to the modulated drive signal.

Abstract: A MEMS device comprising a substrate; an anchored end connected to the substrate; and an actuator comprising a first electrode; a piezoelectric layer over the first electrode; and multiple sets of second electrodes over the piezoelectric layer, wherein each of the sets of second electrodes being defined by a transverse gap there between, and wherein one of the sets of second electrodes are actuated asymmetrically with respect to a first plane resulting in a piezoelectrically induced bending moment arm in a lateral direction that lies in a second plane. The device further comprises an end effector opposite to the anchored end and connected to the actuator; a ferromagnetic core support structure connected to the end effector; a movable ferromagnetic inductor core on top of the ferromagnetic core support structure; and a MEMS inductor coiled around the ferromagnetic core support structure and the movable ferromagnetic inductor core.

Abstract: An electro-mechanical wave device which may be used for movement of a mechanical member, e.g. by friction, a motor comprising one or more wave devices, and a method of providing the electro-mechanical wave device. The electro-mechanical wave device comprises a substrate comprising a plurality of conductors, and a plurality of actuators positioned on the substrate for generation of mechanical waves along a predetermined propagation path, each of the actuators being connected to a respective set of the conductors of the substrate for reception of an excitation signal transmitted by the set of conductors.

Abstract: A piezoelectric actuator includes: a ring-shaped piezoelectric element, vibration of the piezoelectric element being transmitted to an object; a first vibration area and a second vibration area provided on both sides of a bisector bisecting the piezoelectric element along a diameter of the piezoelectric element, the first vibration area and the second vibration area being respectively provided with at least one drive electrode to which a drive signal is supplied, the drive electrode being arranged substantially axisymmetrically with respect to the bisector, the drive signal including a phase-advance drive signal and a phase-delay drive signal having a predetermined drive phase difference, the phase-advance drive signal that is phase-advanced relative to the phase-delay drive signal being supplied to one of the first vibration area and the second vibration area and the phase-delay drive signal that is phase-delayed relative to the phase-advance drive signal being supplied to the other of the first vibration ar

Abstract: To provide a drive detection means for a piezoelectric actuator that can detect an amount driven without requiring adding an encoder or other component while also preventing increasing the load. A rotor is disposed eccentrically to the axis of rotation to change the pressure applied from the rotor to a contact part as the rotor is driven. When the pressure changes, the amplitude of the detection signal output from the detection electrode 18 of the piezoelectric element changes in conjunction with rotor rotation, and how much the rotor has been driven can be detected by detecting the amplitude change. Size and thickness can therefore be reduced because providing an encoder, switch, or other component is unnecessary, and current consumption can also be reduced.

Abstract: An ultrasonic motor that is capable of stable driving by preventing uneven rotation of a driven body and maintaining the drive efficiency is provided. The ultrasonic motor includes a plurality of ultrasonic transducers including alternately stacked first piezoelectric elements and second piezoelectric elements, and a control unit for applying the same two-phase driving AC voltages to the plurality of ultrasonic transducers. The ultrasonic motor simultaneously generates longitudinal vibration and flexural vibration at the ultrasonic transducers to generate substantially elliptic vibration at output ends of the ultrasonic transducers and relatively moves the ultrasonic transducers and a driven body in contact with the ultrasonic transducers.

Abstract: An ultrasonic motor includes a stator that includes a comb body with a plurality of circumferentially-arranged comb-like projections and a piezoelectric body integrally mounted on the comb body, a rotor rotatable with respect to the stator, the rotor having a contact surface that establishes pressure contact with the stator, and a driving circuit configured to apply a radio frequency voltage for driving the piezoelectric body to the piezoelectric body. The driving circuit includes a voltage generating unit configured to generate a first radio frequency voltage of which a frequency is randomly varied during a predetermined time period after start-up of the ultrasonic motor.

Abstract: The present invention provides a piezoelectric ultrasonic motor driver which can perform self-oscillation, adjust the rotational direction of the motor, and be easy to manufacture. The motor includes a metal body having a desired shape; a plurality of piezoelectric plates attached to surfaces of the metal body, contracted and expanded to rotate the metal body; a self-oscillation unit for oscillating at an electromechanical frequency of the piezoelectric plates an electrical signal; and a delay unit for delaying an oscillation signal of the self-oscillation unit in phase by 90 or ?90 degrees according to a desired rotational direction.

Abstract: An ultrasonic motor drive device capable of prolong the service life of an ultrasonic motor by preventing the motor from being unstably operated when the motor is driven at a lower speed of at least two speeds. When the ultrasonic motor (3) is driven at a rather low speed in normal driving, the motor can be prevented from being unstably operated by its driving at a rather low speed by driving the motor at a rather high speed for each specified interval. Thus, the service life of the ultrasonic motor can be increased.

Abstract: Provided is a driving system for a vibrating type actuator capable of simplifying a driving circuit. A vibrating body of the vibrating type actuator can generate a first mode and a second mode which are different in a vibration form, in accordance with an alternate current signal to be supplied. An alternate current signal having a frequency close to a resonance frequency in the first mode or the second mode is applied either between an electrode Va and a common electrode Vc or between an electrode Vb and the common electrode Vc of the vibrating body of the vibrating type actuator. One of the electrodes to be supplied with the alternate current signal is selected by a switching element operated based on a signal from a driving direction switch.

Abstract: A piezoelectric driving device and a regulation method for a piezoelectric driving device are proposed. Piezoelectric driving devices known so far show a characteristic with which the electric power applied to the motor drops when the load increases. This behavior, which leads to a strong reduction of the range of use of such motors, is counteracted by predefining the amplitude of the excitation voltage so that the effective power does not drop with increasing load. For this purpose the electrical effective power is determined from the excitation voltage and the current flowing through the piezoelectric resonator. Alternatively, with a predefined fixed phase angle between excitation voltage and current a regulation may also be effected in the way that the current is kept to the constant value. A further aspect of the invention relates to a unit for limiting the current flowing through the piezoelectric resonator, so as to avoid this component being damaged.

Abstract: A flowmeter element is used for measuring a mass flow rate of fluid, and includes a semiconductor board, an ultrasonic unit and a pressure detecting unit. The ultrasonic unit performs at least one of sending ultrasonic wave and receiving ultrasonic wave. The pressure detecting unit detects a pressure of the fluid. The ultrasonic unit and the pressure detecting unit are integrally disposed on the semiconductor board.

Abstract: The invention provides an ultrasonic motor including internal electrodes provided in an ultrasonic vibrator and disposed in regions where electrical charges of the same sign are generated in one vibration mode and where electrical charges of opposite sign and substantially the same amount are generated in another vibration mode; and a control unit configured to detect a phase difference between a vibration detection signal detected on the basis of electrical signals from the internal electrodes and any one of driving AC voltages, and to set a driving frequency such that the phase difference becomes a reference phase difference. Each driving AC voltage with the driving frequency set by the control unit is applied to the ultrasonic vibrator.

Abstract: A drive apparatus for a piezoelectric actuator prevents locking drive frequency in a state of resonance due to harmonics. There is no need to provide external components to filter, and circuitry can easily be reduced in size. The drive apparatus has a phase difference-DC conversion circuit to detect vibrating state of the vibrating body, a comparison circuit, a harmonics detection circuit to detect that the vibrating body is resonating due to harmonics and outputting a harmonics detection signal, an integration circuit to control the frequency of the drive signal supplied to the piezoelectric element of the vibrating body, a variable frequency oscillation circuit, and a drive circuit.

Abstract: A frequency of a drive signal supplied to a piezoelectric element is swept within a specific range, a detection signal indicating the vibrating state of a vibrating member is detected, and the sweep speed of the drive signal frequency supplied to the piezoelectric element is controlled based on this detection signal. Thus, even if nonuniformities occur in the drive frequency of the piezoelectric element due to fluctuations in the surrounding temperature or the load, such nonuniformities can be overcome without any adjustments, and the piezoelectric element can be reliably driven. Also, since the sweep speed of the drive signal frequency is at a high speed when the vibrating member is in a non-drive state, needless drive signal output time during which the piezoelectric element cannot be driven can be reduced, needless power consumption can be curtailed, and nonuniformities in the drive speed of the driven object can also be reduced.

Abstract: In a drive apparatus having a vibration-generator including a plurality of electromechanical conversion elements, a plurality of weights located between each of the electromechanical conversion elements, and a rod fixed to one end of an electromechanical conversion element, a mass and a spring constant of each component included in the vibration-generator are determined, so that a relationship of integral multiple is satisfied. Thus, highly efficient driving with taking advantage of the resonance frequencies can be realized, and thus the energy consumption can be saved.

Abstract: The present invention relates to apparatus achieving improvement in operation characteristics in the operation of stopping or reversing the direction of or decelerating movement of a vibrating wave actuator constructed to apply an alternating voltage to an electro-mechanical energy conversion element to vibrate a vibration member to obtain a driving force. In the operation of stopping the vibrating wave actuator, it is necessary to cancel the vibration to stop the actuator, in order to stop the actuator in good response. The present invention has achieved the above object by applying an excitation signal, which excites vibration in a direction to cancel free vibration in the vibration member, to the electro-mechanical energy conversion element in the stop operation or the like.

Abstract: A control apparatus and a control method for a vibration type driving apparatus are disclosed which can maintain output performance even when low-speed driving is continued for a long time. The vibration type driving apparatus comprises a vibrating body and an electro-mechanical energy conversion element, and a contact body in contact with the vibrating body. By applying a plurality of driving signals to the electro-mechanical energy conversion element to excite a traveling vibration on the vibrating body, the vibrating body and the contact body are relatively moved. The control apparatus and the control method controls the driving signals such that the largest displacement of the traveling vibration fluctuates and a position where the largest displacement reaches the peak is changed in a direction of the relative movement of the vibrating body and the contact body.

Abstract: A drive device for a piezoelectric actuator, wherein the time needed to achieve highly efficient drive conditions is shortened to reduce power consumption, and stabilized control can be performed. The device has a phase difference detection device (phase difference/voltage conversion circuit (51)) for detecting detection signals of longitudinal oscillation and bending oscillation from an oscillator (5) and detecting the phase difference between these two signals, frequency control devices (52 to 56) for comparing the phase difference detected by the phase difference detection device with a standard phase difference value and controlling the frequency of a drive signal sent to a piezoelectric element (17) on the basis of the results of this comparison, and an amplitude detection device (amplitude detection circuit (57)) for detecting the amplitude of the detection signal of the piezoelectric element (17).

Abstract: A driving device for an ultrasonic actuator for driving a movable member is provided with a member sensor for detecting a present position of the movable member, a calculator for calculating a control target position of the movable member, a driving circuit for generating such a drive voltage as to drive the ultrasonic actuator in a specified resonant state, and a control circuit for controlling an operative state of the movable member by adjusting at least one of physical quantities specifying the drive voltage as a maneuverable physical quantity in accordance with a difference between the present position and the control target position so that the movable member pursues the control target position. There can be provided a driving device capable of executing a position servo control while being driven in a specified resonant state, and a position controller and a camera provided with such a driving device.

Abstract: The present invention relates to apparatus achieving improvement in operation characteristics in the operation of stopping or reversing the direction of or decelerating movement of a vibrating wave actuator constructed to apply an alternating voltage to an electro-mechanical energy conversion element to vibrate a vibration member to obtain a driving force. In the operation of stopping the vibrating wave actuator, it is necessary to cancel the vibration to stop the actuator, in order to stop the actuator in good response. The present invention has achieved the above object by applying an excitation signal, which excites vibration in a direction to cancel free vibration in the vibration member, to the electro-mechanical energy conversion element in the stop operation or the like.

Abstract: An ultrasonic motor comprises a piezoelectric vibrating member having a detecting polarized portion for detecting a drive signal having a drive frequency of the detecting polarized portion and a driving polarized portion for receiving the drive signal to oscillate the piezoelectric vibrating member in self-excited oscillation to produce a drive force. The detecting polarized portion is disposed at a portion of the piezoelectric vibrating member for undergoing maximum deformation in at least one vibration mode of oscillation of the piezoelectric vibrating member. An amplifying circuit amplifies the drive signal detected by the detecting polarized portion and inputs the amplified signal to the driving polarized portion to oscillate the piezoelectric vibrating member.

Abstract: A power output stage for capacitive loads includes: an energy storage inductance, having one end connected to a reference potential and an opposite end connected on the input side to a power supply connection and on the output side to a secondary energy storage capacitance; a primary energy storage capacitance is connected upstream of the energy storage inductance on the input side, and connected on the input side via a primary switching element with a reference potential, and a secondary switching element connected in series with the secondary energy storage capacitance (4), characterized in that the input of the power output stage is clocked by an additional switch.

Abstract: An ultrasonic-actuator driving apparatus includes an ultrasonic actuator including a transducer and a driven body that is in contact with the transducer, the transducer to which a frequency signal is applied friction-driving the driven body; an original-signal outputting unit for outputting an original signal; a waveform averaging unit for averaging the original signals during a predetermined period to calculate average-waveform data; a position detecting unit for detecting an absolute position of the driven body with respect to the transducer; a position averaging unit for averaging the absolute positions during a predetermined period to calculate average-position data; a control-signal calculating unit that generates a control signal for controlling the frequency of the original signal based on the average-waveform data and the average-position data and supplies the control signal to the original-signal outputting unit; and a driving unit for generating the frequency signal based on the original signal and

Abstract: A control apparatus for a vibration type actuator is disclosed, with which at least three kinds of vibrations are excited, and a desired motion can be carried out with high efficiency. The vibration type actuator includes a rotatable moving member, an elastic member contacting the moving member, and an electro-mechanical energy conversion element exciting at least three different kinds of vibrations in the elastic member by supplying at least three periodic signals having different phases. The control apparatus includes a rotation axis determining unit, a parameter determining unit and a control circuit. The rotation axis determining unit determines a rotation axis for rotating the moving member. The parameter determining unit determines, by using an inverse model, phase and amplitude of the periodical signals.

Abstract: A piezoactuator has a diaphragm, and the diaphragm has flat piezoelectric elements that oscillate in a longitudinal oscillation mode and a sinusoidal oscillation mode. A first electrode for detecting oscillation in the longitudinal oscillation mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed on the surface of the diaphragm. When the piezoactuator is driven with a drive signal, the phase difference of a first detection signal output from the first electrode and a second detection signal output from the second electrode is detected. The frequency at which the detected phase difference becomes the maximum phase difference is then obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.

Abstract: An actuator using a piezoelectric element. The actuator includes: the piezoelectric element, which is capacitive; an inductor; and a resistor. The piezoelectric element, the inductor and the resistor are serially arranged so as to define a serial circuit. When a suitable voltage is supplied to the serial circuit, a saw-tooth waveform voltage is applied to the piezoelectric element so that the piezoelectric element extends at a speed and compresses at a different speed repeatedly.

Abstract: An actuator using a piezoelectric element and an operating method thereof. The actuator includes: the piezoelectric element; a drive rod fixed to the piezoelectric element; a moving unit engaging with the drive rod by a frictional force; and a driver for applying a voltage to the piezoelectric element. The voltage repeats a cycle of a first value which is one of a maximum value and a minimum value, a second value which is intermediate between the maximum value and the minimum value, and a third value which is the other of the maximum value and the minimum value so as to drive the driving unit with respect to the drive rod.

Abstract: A smooth impact drive mechanism utilizing an electromechanical conversion element, in which a preheating voltage to preheat the electromechanical conversion element is impressed thereto before the impression of a drive voltage to the electromechanical conversion element, in order to realize stable drive characteristics by reducing fluctuation in the speed of the moving unit. In addition, drive parameters are changed in accordance with the temperature of the electromechanical conversion element. Furthermore, drive parameters are changed in accordance with the moving speed of the moving unit.

Abstract: An actuator using vibration caused by a piezoelectric element. The actuator includes: an driving rod bonded to one of the piezoelectric element; a engaging member for engaging frictionally with the driving rod; and a control circuit for applying the piezoelectric element with a driving voltage. The control circuit is provided with a drive circuit which generates a first set of the driving voltage for driving the engaging member, and with a friction reducing circuit which generates a second set of the driving voltage for reducing a frictional force exerting between the driving rod and the engaging member.

Abstract: A method of forming a resist pattern on a substrate, comprises the steps of: forming a resist film on the substrate, supplying a developing solution onto the resist film, submerging the substrate and the resist film formed thereon in a rinsing liquid kept in a rinsing tank, and applying ultrasonic vibration to the rinsing liquid to rinse the developing solution from the resist film submerged in the rinsing liquid.

Abstract: In a truss-type driving apparatus, the amplitude of each displacement member and the phase difference therebetween are detected, and by adjusting the amplitudes or the phases of the impressed voltages to drive the displacement members based on the results of such detection, the elliptical locus drawn by the synthesizing member of the truss-type driving apparatus during driving is adjusted such that the desired driving characteristics are obtained.

Abstract: The invention relates to a piezoelectric drive device with a bimodal piezoelectric resonator, with at least a first control electrode for triggering the resonator in a first drive direction, with at least a second control electrode for triggering the resonator in a second drive direction, and with a trigger circuit for supplying control signals to the first and the second control electrode. The invention is characterized in that a regulating circuit is provided for regulating the control signals, the second control electrode is designed for supplying a feedback signal to the regulating circuit when the resonator is being triggered in the first drive direction by means of the first control electrode, and the first control electrode is designed for supplying a feedback signal to the regulating circuit when the resonator is being triggered in the second drive direction by means of the second control electrode.

Abstract: The invention relates to a circuit arrangement for the dynamic control of ceramic solid-state actuators, such as piezotranslators with energy recovery by means of magnetic intermediate stores and/or storage capacitors as well as by clocked switches. For achieving a predetermined linear voltage characteristic at the piezotranslator, according to the invention, a single inductive intermediate store is arranged in the secondary circuit, which is connected in series with the piezotranslator, and the secondary circuit is designed as a half-bridge. The switches provided in the respective half-bridge are controlled at a high cycle or switching frequency by an external controller, with the series connection of piezotranslator and inductive intermediate store furthermore carrying a superimposed bridge direct current in order to ensure the desired charging of the capacitance of the piezotranslator, on the one hand, and to optimize the energy recovery, on the other hand.

Abstract: In a self-excited oscillator circuit, a buffer is connected to an electrode or electrodes, and a buffer and an inverter are connected to an electrode or electrodes. Each of the inverters and and the buffer has a tri-state configuration and is capable of setting an output terminal in a high-impedance state, i.e., turning off an output signal, according to a signal input to a control terminal. Therefore, it is possible to turn off a drive circuit and the ultrasonic motor by setting the inverter in the high-impedance state. It is also possible to change the direction of movement of the moving member by setting one of the buffer and the inverter in the high-impedance state.

Abstract: A control apparatus controls an ultrasonic motor. The ultrasonic motor includes a stator, a piezoelectric element provided in the stator, and a rotor. The rotor is slidably pressed against the stator. When a driving high frequency voltage is applied to the piezoelectric element, the stator is vibrated to rotate the rotor. The control apparatus includes measuring means. The measuring means changes the frequency of a searching high frequency voltage, the searching high frequency voltage being lower than the driving high frequency voltage, thereby measuring a resonance frequency of the ultrasonic motor. The control apparatus drives the motor in a favorable manner.

Abstract: A driving apparatus includes an electromechanical conversion element that expands and contracts through the application of a drive voltage, the electromechanical conversion element includes a first end and a second end. The apparatus further includes a support member that is fixed to the first end of the electromechanical conversion element in a direction of expansion or contraction of the electromechanical conversion element; a drive member that is fixed to the second end of the electromechanical conversion element in the direction of expansion or contraction; an engaging member that engages with the drive member with a friction force; and a drive circuit that drives the electromechanical conversion element.

Abstract: An apparatus and method for driving an ultrasonic motor to reduce the rise response time. The ultrasonic motor is drivable at different frequencies and has a desired target speed, each frequency corresponding to a respective speed and a respective torque. The ultrasonic motor enters a specific mode after being started and driven. When the ultrasonic motor is started, a drive control unit drives the ultrasonic motor at a frequency corresponding to approximately a maximum torque. When the ultrasonic motor enters the specific mode, the drive control unit drives the ultrasonic motor at a frequency corresponding to approximately the target speed. Alternatively, the ultrasonic motor can be driven at different drive voltages, each drive voltage having corresponding frequencies, with each frequency of each drive voltage corresponding to a respective speed and a respective torque. The ultrasonic motor enters a specific mode after being started and driven.

Abstract: An object of the present invention is to improve electro-mechanical energy conversion efficiency and reduce generation of noises in a vibration type actuator. To achieve the above object of the present invention, each of plural switching elements is operated by a switching pulse generated by a drive control circuit of the motor. As a result, the drive control circuit selects a width of the generated switching pulse such that the amplitude of a base wave frequency component (“base wave”) among frequency components of a voltage applied to an inductance element may be larger than a total amplitude of higher harmonic wave frequency components (“whole higher harmonic wave”).

Abstract: An ultrasonic-motor control system includes an ultrasonic motor, a controller which starts the ultrasonic motor by changing a drive frequency of the ultrasonic motor from an initial drive frequency, a calculation device which calculates an initial drive frequency data based on a drive frequency at the commencement of rotation of the ultrasonic motor, and a setting device which sets the initial drive frequency based on the initial drive frequency data at a subsequent commencement of driving of the ultrasonic motor.

Abstract: Power circuit for traveling or standing wave piezo-electric motors comprising a series resonant circuit, a switching element (T1) in parallel with the capacitor C of the resonant circuit and a switching element control (O) ensuring the cyclic closure thereof at a frequency close to the resonant frequency of the resonant circuit. The power circuit includes a transformer (Tr) whose primary constitutes the inductance of the resonant circuit and whose secondary is linked to the piezo-electric exciter, this transformer exhibiting a small magnetic inductance at the primary. An advantage of this power supply is in particular the almost-zero heating of the switching element and low current consumption.

Abstract: A piezoactuator has a diaphragm, and the diaphragm has flat piezoelectric elements that oscillate in a longitudinal oscillation mode and a sinusoidal oscillation mode. A first electrode for detecting oscillation in the longitudinal oscillation mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed on the surface of the diaphragm. When the piezoactuator is driven with a drive signal, the phase difference of a first detection signal output from the first electrode and a second detection signal output from the second electrode is detected. The frequency at which the detected phase difference becomes the maximum phase difference is then obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.