• 한국정밀공학회지
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• 제20권4호
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• pp.151-157
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• 2003

A new type of precision actuator is developed using piezoelectric bimorphs. This type of actuator is applicable for the flat surface or in-pipe system and can make forward and backward motion. Two bimorphs are linked serially and two different phased voltages are applied to each bimorph. Therefore, The end of the bimorph makes ellipsoidal motion. The device moves by the friction force between the rubber attached at the bimorph end and the inner surface of the pipe. As the results, the driving range of the device is about 0~18Hz and the device guarantees very high linearity at low frequency, 0~1 Hz. The maximum velocity of the device is about 6mm/s at 10Hz. The developed mechanism is very simple and use piezoelectric bimorph. So, it is possible to miniaturize and educe the power consumption.

• 한국재료학회지
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• 제17권5호
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• pp.289-292
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• 2007

Although piezoelectric bimorph that is using as the sensor in medical and industrial measurement has large displacement, it has problems including efficiency in generating force, energy convergence, and response. Its application is being limited based on the change in resonance frequency with temperature. In this study, to overcome the disadvantages, PZT piezoelectric ceramics was prepared and produced a parallel type piezoelectric bimorphs. In addition, by using the finite element method. the configuration of piezoelectric bimorph was designed and the displacement of the bimorph based on applied electric pressure and the wave pattern were measured. By analyzing the resonance characteristics of the bimorph in the temperature range of $-60{\sim}80^{\circ}C$, an attempt was made to study the operational characteristics and temperature reliability of vortex flowmeter sensor. As a result, the resonance frequency of the bimorph was gradually increased with the temperature from $-60{\sim}80^{\circ}C$. The deflection of the bimorph was found to strongly depend on both the applied electric field waveform and the environmental temperature.

• 한국세라믹학회지
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• 제34권4호
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• pp.337-342
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• 1997

This paper describes the design and evaluation of new type piezoelectric bimorph actuator that shows much large mechanical response than those conventional types. The bimorph actuator has modified structure combined with the multilayer actuator(MLA) and the composite multilayer actuator called "Moonie". The design and performancean alysis of bimorph actuator are carried out with Finite Element Method (FEM). Theoretical calculation results show that the generating force and displacement of Moonie-modified bimorph actuator can be improved by about 130% and 150%, respectively. The overshooting and ringing phenomena of the bimorph can be effectively restrained by the pseudo step electric field having a rising time coincied with a period of the fundamental vibration mode of the bimorph.e bimorph.

• Transactions on Electrical and Electronic Materials
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• 제15권4호
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• pp.226-229
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• 2014

In this study, lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics and a bimorph-type piezoelectric actuator were fabricated using the normal oxide-mixed sintering method, and their dielectric properties, microstructure, and displacement properties were investigated. From the results of X-ray diffraction, the pattern of the specimen has a pure perovskite structure. In addition, no secondary impurity phases were found. The excellent piezoelectric coefficient of $d_{33}=454pC/N$, the electromechanical coupling factor $k_p=0.51$, the dielectric constant ${\varepsilon}_r=3,657$, the mechanical quality factor $Q_m=239$, and $T_c$(Tetragonal-Cubic) =$90^{\circ}C$ were shown at x= 0.085. ${\Delta}k_p/k_p20^{\circ}C$ and ${\Delta}f_r/f_r20^{\circ}C$ showed the maximum value of -0.255 and 0.111 at $-20^{\circ}C$ and $80^{\circ}C$, respectively. The maximum total-displacement was $60{\mu}m$ under the input voltage of 50 V. As a result, it is considered that lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics is a promising candidate for piezoelectric actuator application for x= 0.085.

• 전기학회논문지
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• 제59권3호
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• pp.581-587
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• 2010

Using piezoelectric elements to harvest energy from ambient vibrations has been of great interest over the past few years. Due to the relatively low power output of piezoelectric materials, there are many study to improve the energy harvesting efficiencies. This paper is study the efficiencies of the output energy considering the cantilever piezoelectric bimorph using aluminum vibration beam. when the length of vibration beam and the piezoelectric body becomes same and the maximum output power comes out. DC voltage was increased as the beam thickness and vibration frequency was increased. The vibration beam was able to achieve very large energy value.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.143-144
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• 2008

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.806-809
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• 1988

The frequency response characteristics of a bimorph type PZT piezoelectric transducer was investigated. In this study, function generator which generates short burst signal, plane reflection plate and oscilloscope were used to measure the characteristics of piezoceramic ultrasonic transducer. The resonant frequency of a bimorph type piezoceramic transducer which is acquired by using Tone-Burst Method had good agreement with the measured results from spectrum analyzer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.305-310
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• 2013

This paper analyzes three cantilever-types of piezoelectric actuators of bimorph, unimorph and monomorph in same volume to maximize tip displacement. Tip displacement of each actuator is theoretically derived by using beam theory and numerically verified by FEM. It also investigates the tip displacements of each actuator due to the change of elastic layer. It shows that the piezoelectric actuator of bimorph generates the largest tip displacement among them.

• 소음진동
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• 제7권3호
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• pp.377-386
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• 1997

A cantilever type piezoceramic vibration sensor was developed that could make up for the short-comings of current vibration sensors, such as high price, low sensitivity, and complex structure. For the design, in conjunction with piezoelectric constitutive equations, we derived full analytic response equations of the piezoelectric bimorph sensor to external forces. The external forces were supposed to take the form of either step or sinusoidal force. Based on the results, actual piezoelectric vibration sensors were fabricated and tested for verification of the theoretical results. Further, comparison of the performance of the developed sensor was made with that of a commercially available representative vibration sensor so that quantitative evaluation of its sensitivity could be made. The sensor developed in this work showed excellent sensitivity and thermal stability in addition to the merits of simple structure and low fabrication cost in comparison with conventional mass-loaded piezoelectric sensors.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.488-491
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• 2006

In this paper, a slim type actuator is proposed rising a bimorph PZT and a circular rotor link. The bimorph contacts the circular rotor, and its displacement generates the rotational motion of the rotor. The rotor causes the linear motion of AF and zoom lens through gear and a motion guide. The proposed model enables the actuations of many lens groups for zoom module by extending the single lens model. The important design parameter is the contact force determined by the frictional coefficient and preload between the rotor and PZT bimorph. A prototype of the single actuator model is manufactured and experiments results using LDV and tachometer are compared to the theoretical and numerical predictions. Experiments show the linear bimorph actuator model meets the performance criteria of the lens actuation, and it can be applicable to various slim type actuators for AF and zoom motions in mobile cameras.