Showing papers on "Piezoelectric motor published in 2015"

A review of long range piezoelectric motors using frequency leveraged method

Abstract: This paper provides a comprehensive review of the literature regarding precision piezoelectric motors over long ranges based on the principle of repeating a series of small periodic step motions, named “frequency leveraged motors” in this paper. A summary of recent research into frequency leveraged motors is presented. Work is classified into three categories by different frequency driving methods, including ultrasonic motors, quasi-static motors (non-resonant motors), and motors combined resonant and quasi-static operations. Pros and cons of each motor type are discussed in term of their principle, structure, and performance. In addition, future perspectives and improvements of the frequency leveraged motor are also provided. It is summarized in such a way can provide a better understanding of the core characteristics of each type of long range piezoelectric motor. Moreover, it also aids in determining successful designs, suitability for applications and further research areas.

Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

Abstract: This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

Piezoelectric energy harvesting through shear mode operation

Abstract: Piezoelectric materials are excellent candidates for use in energy harvesting applications due to their high electromechanical coupling properties that enable them to convert input mechanical energy into useful electric power. The electromechanical coupling coefficient of the piezoelectric material is one of the most significant parameters affecting energy conversion and is dependent on the piezoelectric mode of operation. In most piezoceramics, the d15 piezoelectric shear coefficient is the highest coefficient compared to the commonly used axial and transverse modes that utilize the d33 and the d31 piezoelectric strain coefficients. However, complicated electroding methods and challenges in evaluating the performance of energy harvesting devices operating in the shear mode have slowed research in this area. The shear deformation of a piezoelectric layer can be induced in a vibrating sandwich beam with a piezoelectric core. Here, a model based on Timoshenko beam theory is developed to predict the electric power output from a cantilever piezoelectric sandwich beam under base excitations. It is shown that the energy harvester operating in the shear mode is able to generate ~50% more power compared to the transverse mode for a numerical case study. Reduced models of both shear and transverse energy harvesters are obtained to determine the optimal load resistance in the system and perform an efficiency comparison between two models with fixed and adaptive resistances.

Dynamic analysis of an ultrasonic motor using point contact model

Abstract: We propose the dynamic modeling of a traveling wave ultrasonic motor using a point contact model between the stator and rotor This model can simply and accurately estimate the transient response of the rotor motion In this paper, we model the dynamic behavior of the motor torque and angular velocity based on the vibration amplitude of the elliptical motion generated in the ultrasonic motor The use of a recent high-speed camera with a high-power lens (high-speed microscope) enables the observation of elliptical motion and the measurement of vibration amplitudes We build a synchronous motor drive system including the high-speed microscope and verify the model experimentally The proposed model has been in good agreement with the experimental results

Dual piezoelectric beam robot: The effect of piezoelectric patches’ positions

Abstract: Inspired from linear traveling wave ultrasonic motors, a dual piezoelectric beam robot is presented. It consists of an aluminum beam structure, with two non-collocated piezoelectric patches bonded ...

Block diagrams of a multilayer piezoelectric motor for nano- and microdisplacements based on the transverse piezoeffect

Abstract: A parametric block model and block diagrams of a multilayer piezoelectric motor based on the transverse piezoelectric effect with account for the electromotive counterforce emerging at its stress as a result of response to the applied force in the direct piezoelectric effect are obtained. Transfer functions of the piezoelectric motor with regard to its geometric and physical parameters, electromotive counterforce, and external load are determined.

Performance evaluation of a micro ultrasonic motor using a one-cubic-millimeter stator

Abstract: A piezoelectric ultrasonic motor has two significant advantages, high energy density and simple structure, and these advantages can help in the miniaturization of the motor. We build a prototype micro ultrasonic motor using a stator with a volume of approximately 1 cubic millimeter. To evaluate its representative performance values (torque, angular velocity, and energy efficiency), we built an experimental setup and operated the prototype motor by varying experimental conditions, such as the preload between the stator and rotor and the amplitude of voltages applied to motor. The performance values obtained at the millimeter to sub-millimeter scale are discussed analytically using the macro scale models of ultrasonic motors. Experimentally, the prototype motor has generated a torque of more than 10 μNm with a 1-cubic-millimeter stator. The motor described herein is now the smallest micro ultrasonic motor with a practical torque, although its efficiency is still low.

A Novel Rotary Piezoelectric Motor Using First Bending Hybrid Transducers

Abstract: We report a novel rotary piezoelectric motor using bending transducers in this work. Three transducers are used to drive a disk-shaped rotor together by the elliptical movements of their driving tips; these motions are produced by the hybrid of two first bending vibration modes. The proposed piezoelectric transducer has a simple structure as it only contains an aluminum alloy beam and four pieces of PZT plates. Symmetrical structure is the only necessary condition in the design process as it will ensure the resonance frequencies of the two orthogonal first bending modes are equal. Transducers with first bending resonance frequency of about 53 kHz were fabricated and assembled into a rotary motor. The proposed motor exhibits good performance on speed and torque control. Under a working frequency of 53.2 kHz, the maximum no-load speed and the maximum torque of the prototype are tested to be 53.3 rpm and of 27 mN·m.

Thermo-elastic damping in a functionally graded piezoelectric micro-resonator

Abstract: The present study investigates the thermo-elastic damping (TED) of transversal vibration in a functionally graded piezoelectric (FGP) micro-beam resonator. The model is a functionally graded silicon-piezoelectric fully clamped micro beam exposed to a DC piezoelectric tuning voltage. The object is to propose a novel FGP MEM system, with a controllable thermo-elastic damping. It is shown that the functionality of the material distribution not only reduces the TED ratio, but also enables tuning the resonance frequency of the resonator due to the piezoelectric actuation. The effects of portion of piezoelectric material, geometrical dimensions, the ambient temperature and tuning DC voltage, on the quality factor of the flexural vibrations of the structure is analyzed through solving the thermo elastically coupled dynamic equations of the motion.

An adaptive piezoelectric vibration absorber enhanced by a negative capacitance applied to a shell structure

Abstract: Piezoelectric shunt damping is a well-known technique to damp mechanical vibrations of a structure, using a piezoelectric transducer to convert mechanical vibration energy into electrical energy, which is dissipated in an electrical resistance. Resonant shunts consisting of a resistance and an inductance connected to a piezoelectric transducer are used to damp structural vibrations in narrow frequency bands, but their performance is very sensitive to variations in structural modal frequencies and transducer capacitance. In order to overcome this drawback, a piezoelectric shunt damping technique with improved performance and robustness is presented in this paper. The design of the adaptive circuit considers the variation of the host structure's natural frequency as a project parameter. This paper describes an adaptive resonant piezoelectric vibration absorber enhanced by a synthetic negative capacitance applied to a shell structure. The resonant shunt circuit autonomously adapts its inductance value by comparing the phase difference of the vibration velocity and the current flowing through the shunt circuit. Moreover, a synthetic negative capacitance is added to the shunt circuit to enhance the vibration attenuation provided by the piezoelectric absorber. The circuitry is implemented using analog components. Validation of the proposed method is done by bonding the piezoelectric absorber on a free-formed metallic shell.

Influence of the excitation parameters of the mechanical subsystem on effectiveness of energy harvesting system

Abstract: Piezoelectric transducers are used more and more often in modern technical devices. The wide range of their possible applications is a result of the possibility to use both direct and reverse piezoelectric effect. Nowadays, application of piezoelectric transducers in energy harvesting systems is getting more and more popular. It is caused by the easy way to convert energy of mechanical vibration to the electric voltage using piezoelectric transducers. This paper presents results of influence analysis of the vibrating mechanical subsystem's excitation parameters on the effectiveness of the system designed for energy harvesting. The considered vibrating system is a composite plate with piezoelectric transducer bonded to its surface. Vibrations of the system are excited by means of an actuator with possibility to change the excitation amplitude and frequency. Recovering of electrical energy from mechanical vibrations is possible by using the direct piezoelectric effect - generation of the electric voltage while the transducer is mechanically deformed. In carried out test Macro Fiber Composite (MFC) piezoelectric transducers were used. It was proved that the time that is necessary for switch on the output voltage in analyzed system depends on the frequency of the excitation.

Temperature-sensing piezoelectric dispenser

Abstract: Provided is a temperature-sensing piezoelectric dispenser, and more particularly, to a dispenser including a piezoelectric pump dispensing a liquid by using a piezoelectric element as an actuator. According to the temperature-sensing piezoelectric dispenser, a temperature of a piezoelectric actuator is measured and the piezoelectric actuator is cooled based on the measured temperature, thereby accurately controlling a liquid discharged according to an operation of the piezoelectric actuator.

Electric Impedance of Piezoelectric Ceramics under Acoustic Loads

Abstract: The electric impedance of piezoelectric ceramics is influenced by variations in the acoustic load This situation is very common for ultrasonic applications in medicine where the irradiated media can present different interfaces and impedances to the propagating acoustic energy In this work we analyzed the behavior of the resonances, anti-resonances and the effective electromechanical coupling factor of a piezoelectric ceramic ring vibrating in thickness mode The analysis is based on equivalent electric circuits and considers variations in the acoustic load The results showed that the electric impedance of the ceramic is altered with the length of the acoustic load, resulting in new resonances and changing the effective electromechanical coupling factor Electronic circuits for driving piezoelectric transducers must be able to correct the frequencies if acoustic loads vary

Piezoelectric cantilever-pendulum for multi-directional energy harvesting with internal resonance

Abstract: Piezoelectric transducers are widely employed in vibration-based energy harvesting schemes. Simple piezoelectric cantilever for energy harvesting is uni-directional and has bandwidth limitation. In this research we explore utilizing internal resonances to harvest vibratory energy due to excitations from an arbitrary direction with the usage of a single piezoelectric cantilever. Specifically, it is identified that by attaching a pendulum to the piezoelectric cantilever, 1:2 internal resonances can be induced based on the nonlinear coupling. The nonlinear effect induces modal energy exchange between beam bending motion and pendulum motions in 3-dimensional space, which ultimately yield multidirectional energy harvesting by a single cantilever. Systematic analysis and experimental investigation are carried out to demonstrate this new concept.

Anti-shaking device for lens

Abstract: The invention discloses an anti-shaking device for a lens. The device comprises a Z-axis rotating module and an X-axis rotating module; the lens is arranged on the X-axis rotating module and can rotate relative to the X axis rotating module around an X axis; the X axis rotating module can rotate relative to the Z axis rotating module around an Z axis; rotary piezoelectric motors are arranged on the Z-axis rotating module and the X-axis rotating module and used for correspondingly driving the Z-axis rotating module and the X-axis rotating module to drive; driving control feedback units are arranged on rotating driving motors are arranged on the Z-axis rotating module and the X-axis rotating module; an electronic gyro senses the shaking of the lens, a signal for driving the rotary piezoelectric motor to rotate is sent, and then the driving control feedback unit detects the rotating angle of the rotary piezoelectric motors, so that the angle compensation is correspondingly performed for the shaking of the whole lens, the influence of shaking on the shooting quality is avoided, and as a result, a clear and high-quality photo can be shot through a camera; meanwhile, the device has the characteristics of being simple in structure, small in size, fast to react, accurate to control, small in power consumption, and high in electromagnetic interference resistance.

Modeling of piezoelectric stack actuators considering bonding layers

Abstract: In order to achieve large displacement output of piezoelectric actuators, piezoelectric stack actuators are realized by mechanically layering or stacking multi-chip piezoelectric wafers in series a...

Half-tube array vibration energy harvesting method using piezoelectric materials

Abstract: A piezoelectric transducer for harvesting ambient vibration energy is made up of a curved substructure beam, two half-tube piezoelectric elements and a mass block. One end of the beam is fixed on a vibration base and the other end is attached with the mass block. Two half-tube piezoelectric elements are affixed on the surface of the curved substructure beam. The present invention has a high energy transformation efficiency and a low resonance frequency. It can be applied in implantable devices, wearable electronics and wireless sensor networks.

Piezoelectric ceramic, method for producing the same, piezoelectric element, multilayer piezoelectric element, liquid ejection head, liquid ejecting apparatus, ultrasonic motor, optical device, vibrating apparatus, dust-removing apparatus, imaging apparatus, and electronic device

Abstract: Provided is a piezoelectric ceramic that does not contain any of lead, potassium, and cobalt and has a high Curie temperature, a good mechanical quality factor, and good piezoelectric properties. The piezoelectric ceramic includes a perovskite-type metal oxide represented by General Formula (1), CuO, and MgO. In the piezoelectric ceramic, the content of CuO is 0.1 mol % or more and 1 mol % or less and the content of MgO is 0.1 mol % or more and 2 mol % or less of the content of the perovskite-type metal oxide. (Na x Ba 1-y )(Nb y Ti 1-y )O 3 , where 0.85≦ x ≦0.92, 0.85≦ y ≦0.92, 0.95≦ x/y ≦1.05. General Formula (1):

Towards a digital sound reconstruction MEMS device: Characterization of a single PZT based piezoelectric actuator

Abstract: In this paper we report the fabrication and characterization of a single piezoelectric actuator for digital sound reconstruction. This work is the first step towards the implementation of a true digital micro-loudspeaker by means of an array of acoustic actuators. These actuators consist of a flexible membrane fabricated using polyimide, which is actuated using a Lead-Zirconate-Titanate (PZT) piezoelectric ceramic layer working in the d31 actuation mode. The dimensions of the membrane are of 1mm diameter and 4μm in thickness, which is capable of being symmetrically actuated in both upward and downward directions, due to the back etch step releasing the membrane. Our electrical characterization shows an improvement in the polarization of the piezoelectric material after its final etch patterning step, and our mechanical characterization shows the natural modes of resonance of the stacked membrane.

Piezoelectric element, piezoelectric device, probe, electronic machine, and ultrasonic image apparatus

Abstract: A piezoelectric element includes a vibrating film, a piezoelectric body, a first electrode, a second electrode, and a groove. The piezoelectric body is arranged upon the vibrating film. The first electrode is arranged upon the piezoelectric body. The second electrode is arranged upon the piezoelectric body and at a position that is separated from the first electrode. The groove is located between the first electrode and the second electrode and splits a surface of the piezoelectric body in two, as seen in plan view from a thickness direction of the vibrating film.

Predictive Electromechanical Model for Energy Scavengers Using Patterned Piezoelectric Layers

Abstract: The piezoelectric transduction mechanism is widely used in passive sensing, health monitoring, and energy harvesting. Plate-type energy harvesters are usually discouraged; however, piezoelectric layers on a substrate in a certain pattern were found to be suitable for harvesting energy from a wider band of frequencies. However, to understand the theoretical behavior of the harvesters with any arbitrarily shaped piezo patch, a detailed mathematical model is lacking. This paper proposes a comprehensive analytical model to calculate the frequency response function (FRF) from simply patterned piezoelectric layers. A generalized mathematical form is presented for an arbitrary rectangular piezoelectric patch placed on a host plate. The strain-rate damping mechanism is incorporated for better and more accurate results. First, a comparative study on the strain-rate damping effect is presented by placing the piezoelectric layer on the entire plate. Without strain-rate damping, the model incorrectly estimate...