A method and device are disclosed for actuating a piezoelectric motor by two driving electrodes by applying periodic control voltages to the driving electrodes. A simplified closed-loop control of the piezoelectric motor is realized by reducing the static friction of a friction contact between a friction element of the piezo-electric motor and an output element to be driven by the friction element without a propulsion of the output element at the same time. In exemplary embodiments, the periodic control voltages are applied with a phase shift to the driving electrodes in a first step of the method, and in a second step of the method, the amplitude ratio of the periodic control voltages is changed with respect to the first step.

Method for operating an ultrasonic motor with an ultrasonic actuator formed as a plate and an electrical excitation device. The ultrasonic actuator has at least four identical volume regions arranged symmetrically in relation to a transverse plane and in relation to a longitudinal plane, each volume region forming acoustic standing waves and static bending deformations. The electrical excitation device provides at least one electric alternating voltage and two static electric voltages the at least one alternating voltage U1 being applied in a dynamic operating mode simultaneously to two of the generators for forming an acoustic standing wave in the ultrasonic actuator, and the two static electric voltages being applied in a static operating mode simultaneously to all generators for forming a static bending deformation of the ultrasonic actuator.

In a driver for a piezo-electric transducer, when a converter circuit and a sensing circuit are the same circuit, many limitations exist on the accuracy of the sensing, due to multiple parasitic effects arising from the interconnection of the power devices. These limitations may limit viability of the sensing for many applications, in particular an accurate determination of when the force on the piezo-electric transducer is fully removed. Providing an additional switch in the sensing circuit configured to repeatedly zero the sensed voltage across the piezo-electric transducer each time the sensed voltage reaches a threshold voltage generates a plurality of voltage segments between zero and the threshold voltage. Accordingly, a controller may then be configured to generate a digital reconstruction of the sensed voltage across the piezo-electric transducer by adding the plurality of voltage segments.

Provided are a flexible body and a method for controlling the flexible body to deform. The flexible body comprises one or more flexible units, wherein each of the flexible units comprises: a first electrode, a second electrode, an electroactive polymer layer, and a thin film transistor, wherein a source electrode or a drain electrode of the thin film transistor is electrically connected to the second electrode. The first electrode and the second electrode are configured to provide an electric field acting on the electroactive polymer layer, and the electroactive polymer layer is configured to deform in response to the electric field provided by the first electrode and the second electrode.

Disclosed is electromechanical actuator for ultrasonic motor in the shape of an n-sided regular polygon plate with n being equal to or greater than five. The polygon plate has two larger main surfaces and at least five smaller side surfaces connecting the main surfaces with each other. Two electrodes are arranged on one of the main surfaces and are electrically isolated from each other by a linear isolation area. One electrode is arranged on the other of the main surfaces. The polygon plate comprises an electromechanical material that undergoes a deformation when electric voltage is applied to the electrodes. The material of the electromechanical actuator comprises a single or polycrystalline piezoelectric ceramic with piezoelectric charge constant d31 differing from piezoelectric charge constant d32 both in sign and in value. The piezoelectric charge constants d31 and d32 define a first and second main deformation direction of the actuator perpendicular to each other. The orientation of the linear isolation area is parallel to either deformation direction.

A method for operating a drive unit having an active element with a resonator and an excitation structure for exciting oscillations in the resonator and thereby driving a passive element. The method includes driving the excitation structure with a driving signal, the driving signal being a periodic signal having driving pulses repeated with an excitation frequency. Depending on a control signal, modifying the driving signal, if the control signal is within a first range, by modifying the excitation frequency or modifying the shape of the driving pulses and, if the control signal is within a second range, repeatedly omitting driving pulses.

A zero-voltage zero-current soft switching type driving method for an ultrasonic motor is provided, relating to the technical field of driving of a two-phase actuator. The disclosure solves the problems of high loss, high heat amount and the like in a traditional ultrasonic motor driving circuit. The method provided realizes resonance between series inductors and buffer capacitors by means of an optimal design of the inductance of matching inductors, the capacitance of buffer capacitors, a dead time value and a delay time value, thereby causing a power tube to realize zero-voltage and zero-current switching. Two signal input ends of a two-phase pseudo full bridge inverter are connected to a power grid, and two signal output ends of the two-phase pseudo full bridge inverter are respectively connected to two signal input ends of a matching circuit; and the output ends of the matching circuit are respectively connected to a two-phase ultrasonic motor.

A control method of a piezoelectric driving device which includes a vibrator including a piezoelectric element and vibrating by application of a drive signal to the piezoelectric element, a driven unit moving by the vibration of the vibrator, a drive signal generation unit generating the drive signal based on a pulse signal, the control method including: stopping the application of the drive signal to the piezoelectric element at the time when a driving speed of the driven unit is a reference speed, in a case of stopping driving of the driven unit.

An iterative learning-based energy-saving control method for a piezoelectric motor, comprising: setting a sampling period of a piezoelectric motor (101); obtaining an expected output trajectory of the piezoelectric motor, and performing sampling according to the sampling period to obtain a sampled expected output sequence (102); setting an initial control input signal of the piezoelectric motor (103); obtaining an actual control input signal according to a mapping relation of the initial control input signal, and transmitting the actual control input signal to the piezoelectric motor to obtain an actual output position (104); obtaining a mapping relation of the output position of the piezoelectric motor according to the actual output position, and sampling the mapping relation according to the sampling period to obtain a sampled actual output sequence (105); calculating the difference between the sampled expected output sequence and the sampled actual output sequence to obtain a sampling error function sequence (106); obtaining an iterative learning gain parameter by calculation according to a preset convergence condition (107); and obtaining, by calculation according to the sampling error function sequence and the iterative learning gain parameter, an iterative input voltage required by iteration of the piezoelectric motor, and transmitting the iterative input voltage to the piezoelectric motor (108).

This application relates to methods and apparatus for driving a transducer with switching drivers. A switching driver has first and second supply node for receiving supply voltages and includes an output bridge stage, a capacitor and a network of switches. The network of switches is operable in different switch states to provide different switching voltages to the output bridge stage. A controller is configured to control the switch state of the network of switches and a duty cycle of output switches of the output bridge stage based on an input signal to generate an output signal for driving the transducer.