• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.607-608
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• 2006

This article deals the development of Agile and Intelligent Manufacturing System(AIM) for the assembly automation of a tiny ultrasonic actuator used in camera phones and PDAs. The system consists of multi-vision modules, end-effectors, a standard base frame, dispensers, jigs and modular manipulators. Subsystems are a vision system, a force control system and a virtual reality system. Experimental results show that the assembly process for the small components in the various IT applications can be realized by the AIM system.

• The Journal of the Acoustical Society of Korea
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• v.22 no.3
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• pp.202-207
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• 2003

For medical ultrasonic transducer, phase-weighting method has been used for controlling focal length with electric circuit at each vibrating element. However, the electric circuit is complex as the number of vibrating elements is increased. In this paper, we fabricated line-focus transducer with a bimorph-type piezoelectric actuator. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signal. Using this transducer, focal length of the transducer can be controlled mechanically by changing voltage of the actuator. It is confirmed that focal length of the transducer can be controlled in range of 1095 to radius of curvature.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.190-194
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• 2005

There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile camera phones. However, conventional magnetic coils of electromagnetic motors are a major obstacle for miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM (ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 1.52 mm/s at 10 kHz input signal in 5 V.

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.727-731
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• 1997

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.631-636
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• 2009

This paper presents design and analysis of ultrasonic vibrator featuring the piezoelectric actuator. After describing a geometric configuration of the proposed vibrator, an analytical model of the ultrasonic vibrator is formulated by adopting liquid film pattern theory and wave theory. The dynamic analysis and geometric optimization are then undertaken using a software ANSYS. The optimization is performed by taking the amplitude of the tip displacement as an objective function. The fluid flow characteristics of the proposed vibrator are analyzed by taking three different fluids: water, silicon oil and ethylene-glycol. This is achieved using a software FLUENT.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.12
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• pp.1289-1295
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• 2009

This paper presents design and analysis of ultrasonic vibrator featuring the piezoelectric actuator. After describing a geometric configuration of the proposed vibrator, an analytical model of the ultrasonic vibrator is formulated by adopting liquid film pattern theory and wave theory. The dynamic analysis and geometric optimization are then undertaken using a software ANSYS. The optimization is performed by taking the amplitude of the tip displacement as an objective function. The fluid flow characteristics of the proposed vibrator are analyzed by taking three different fluids: water, silicon oil and ethylene-glycol. This is achieved using a software FLUENT.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1613-1616
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• 1997

In order to develop a human hand mechanism, a 5-bar finger with redundant actuation is designed and implemented. an optimal set of acutator locations and link lengths for the case of one redundant actuator is obtained by employing a composite design index which simulataneously consider several performance indices such as workspace, isotropic index, and force transmission ratio. Each joing is driven by an compact actuator mechanism having ultrasonic motor and a gear set with poeneiometer an controlled by VME Bus-based control system.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.11
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• pp.1121-1128
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• 2013

Ultrasonic grinding system is that the ultrasonic vibration by ultrasonic actuator is applied on conventional grinding system during grinding process. The Ultrasonic vibration with a frequency of over 20kHz can reduce grinding forces and increase surface quality, material removal rate (MRR) and grinding wheel life. In addition, ultrasonic vibration assisted grinding can be used for the materials that are difficult to cut. In this paper, methodology for ultrasonic tools is studied based on finite element method, and in turn the ultrasonic tools are designed and fabricated. It is found that the ultrasonic tool can vibrate with a frequency of 20kHz and amplitude of $25{\mu}m$. In order to verify the machining performance, the grinding experiment is performed on titanium alloy. By applying ultrasonic vibration, the grinding force and temperature are reduced and MRR is increased compared with the conventional grinding.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.33-34
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• 2005

In this study, in odor to develop low temperature sintering multilayer piezoelectric actuator and ultrasonic vibrator, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$ and $Na_2CO_3$ as sintering aids and their piezoelectric and dielectric characteristics were investigated according to the addition of dopant CuO and $Fe_2O_3$, respectively. The CuO added PMN-PNN-PZT ceramics improved mechanical quality factor Qm due to the acceptor doping effect. And also, $Fe_2O_3$ reacted as softner in this composition system in addition to the increase of grain size and sinterability. Taking into consideration electromechanical coupling factor kp of 0.62, dielectric constant $\varepsilon_r$, of 1275, Piezoelectric $d_{33}$ constant of 377[pC/N] and mechanical quality factor Qm of 975, it was concluded that the ceramics with the $Fe_2O_3$, added composition sintered at 900[$^{\circ}C$] were best for the multilayer piezoelectric actuator and ultrasonic vibrator application.

• The Journal of Korea Robotics Society
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• v.3 no.3
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• pp.219-225
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• 2008

This study developed a surveillance robot for a ship. The developed robot consists of ultrasonic sensors, an actuator, a lighting fixture and a camera. The ultrasonic sensors are used to avoid collision with obstacles in the environment. The actuator is a servo motor system. The developed robot has four drive wheels for driving. The lighting fixture is used to guide the robot in a dark environment. To transmit an image, a camera with a pan moving and a tilt moving is equipped on the upper part of the robot. AdaBoost algorithm trained with 15 features, is used for face recognition. In order to evaluate the face recognition of the developed robot, experiments were performed.