Ultrasonic vibration micro-shaping using single PZT actuator-embedded tool holder

Jongsu Kim,이주형,강봉철 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

In this study, we suggest a novel tool holder design for simple and cost-effective ultrasonic vibration shaping to provide improvements such as low cutting force, smooth chip exhaust, and better surface quality in the cutting performance. An ultrasonic vibration tool actuated by a single actuator, which was designed by asymmetrically installing a single PZT actuator inside a cylindrical tool holder, generated the synchronized two-axis ultrasonic vibration motion on the tool tip along the cutting and thrust directions. By conducting dynamic structural analysis and simulating the tool tip movement trajectory using finite element method, the resonance mode, amplitude, and frequency of the model were optimized to achieve the vibration characteristics required for precision micro-shaping processes. According to the experimental evaluations, the vibration of the tool holder was characterized by a resonance mode of 24 kHz. The cutting performance of the tool was evaluated by comparing the cutting force, machined surface, and chip shape with those using a non-vibration micro-shaping tool. The cutting force was reduced more than 90 %, and the machined shape and chip exhaust were improved compared with that in conventional shaping processes.

Medical Microrobot - Wireless Manipulation of a Drug Delivery Carrier through an External Ultrasonic Actuation: Preliminary Results

Han Sol Lee,Gwangjun Go,Eunpyo Choi,Byungjeon Kang,Jong-Oh Park,김창세 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.1

To achieve precise and untethered clinical therapeutics, microrobots have been widely researched. However, because conventional microrobot actuation is based on magnetic forces generated by a magnetic field and magnetic particles, unexpected side effects caused by additional magnetic ingredients could induce clinical safety issues. In this paper, as an alternative to an untethered actuator, we present a novel ultrasonic actuation mechanism that enables drug particle/cell manipulation and micro/nano-robot actuation in clinical biology and medicine. Firstly, characteristics of the acoustic field in the vessel mimic circular tube, formed from particles emerging through a submerged ultrasonic transducer, are mathematically analyzed and modeled. Thereafter, a control method is proposed for trapping and moving the micro-particles by using acoustic radiation force (ARF) in a standing wave of a tangential standing wave. The feasibility of the proposed method could be demonstrated with the help of experiments conducted using a single transducer with a resonance frequency of 950 kHz and a motorized linear stage, which were used in a water tank. The micro-particles in the tube were trapped via ultrasound and the position of the micro-particles could be controlled by frequency manipulation of the transducer and motor control. This study shows that ultrasonic manipulation can be used for specific applications, such as the operation of a micro robot inserted in a peripheral blood vessel and targeted for drug delivery.

Ultrasonic atomization of highly viscous biodegradable oils for MQL applications

Axel Lefebure,심동하 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.12

This paper establishes the vibrating-mesh ultrasonic mist-generation of highly viscous biodegradable oils as a novel implementation for MQL (minimum quantity lubrication) applications. Initial studies on ultrasonic MQL have already been carried out, but the usage of highly viscous biodegradable oils in a non-diluted setup has never been explored. This research studied the atomization rate and mist droplet size distribution, influenced by oil viscosity, and actuator-related properties, such as mesh pore size and driving voltage. Through the FLDC (fibre liquid delivery column) method, using a 113 kHz vibrating mesh piezo actuator, solution feasibility was shown for three currently in-industry-used highly viscous MQL oils, including a maximum liquid viscosity of 37 cSt, higher than the previous record of 28 cSt for ultrasonic atomization. An atomization rate of 13.4 ml/h and mean droplet diameter of 27.5 μm were followingly achieved for this new maximum viscosity. The demonstrated setups and their novel atomization performance data were gathered in the form of a design guide, aiding in the future development of ultrasonically atomized viscous oils for MQL applications.

Driving Characteristics of a Thin Square Frame-type Ultrasonic Motor

박충효,정성수,박태곤 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.6

A thin, square, frame-type ultrasonic motor was proposed for applications in small actuators. The stator is easy to fabricate because of the simple structure where eight piezoelectric ceramics are attached on the thin square frame-shaped elastic body. When two sinusoidal sources with a phase difference of 90 degrees are applied to the stator, elliptical displacements are generated at the four edges of the stator. The designed rotor is revolved by the displacements. A finite element method was used to simulate the generated displacements, and a driving experiment was then conducted to compare the output characteristics with the results of the simulation.

LED 공정의 균일 코팅을 위한 초음파 진동자 설계 및 해석

손병호(Son, Byeoun-Ho),최승복(Choi, Seung-Bok) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.12

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.

Design of a Cross-Type Ultrasonic Rotary Motor with a Simple Structure

정현호,박태곤,정성수,김명호 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.31

In this study, the characteristics of a novel ultrasonic rotary motor with a cross-type stator were investigated. The previous cross-type ultrasonic motor had a stator with 8 piezoelectric ceramics of different poling directions attached, but the new cross-type ultrasonic motor had a stator with only 4 ceramics. The number of ceramics can be reduced by controlling the poling direction of the ceramic. To get an optimized design for the new cross-type ultrasonic motor, we simulated an elastic body by changing the size of the stator. The displacement of the stator was examined by using a finite element analysis. When the thickness of the elastic body was decreased, the displacement increased. When the thickness of the elastic body was decreased, the displacement that occurred in a direction tangential to the contact surface decreased. When the ceramics was thin, the displacement of the stator was observed to be large. These results indicate that the cross-type ultrasonic motor can be miniaturized by controlling the size and the resonant mode of the elastic body.

렌즈 구동을 위한 선형 초음파 전동기 설계

권태성 ( Tae Seong Kwon ),이승엽 ( Seung Yop Lee ),김수경 ( Soo Kyung Kim ) 정보저장시스템학회 2005 추계학술대회논문집 Vol.2005 No.-

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 d31 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.

적층형 압전 액츄에이터를 이용한 L1-B4형 선형 초음파 리니어 모터의 타원변위궤적

이갑수,류주현,황은상,박덕원,Lee, Kab-Soo,Yoo, Ju-Hyun,Hwang, Eun-Sang,Park, Durk-Won 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.1

In this study, multilayer structured ultrasonic linear motor was simulated using Atila for investigating its optimum driving conditions. The ultrasonic linear motors mainly consist of an ultrasonic vibrator to generate elliptical displacement. The ultrasonic linear motor simulated in this paper was the use of the 1st longitudinal(Ll) and 4th bending vibrations (B4). Whit the increase of the number of piezoelectric actuator layers, displacement of node was increased. Maximum total displacement of node was about $3,91{\mu}m$ at the 13 layered ultrasonic motor under 5 V.

초음파 가위의 고효율 구동을 위한 디지털 제어 시스템의 구현

문정호(Jungho Moon) 한국지능시스템학회 2020 한국지능시스템학회논문지 Vol.30 No.6

초음파 가위는 초음파 주파수 대역의 진동을 이용하여 출혈을 최소화하는 방식으로 인체의 조직을 절단할 수 있도록 고안된 수술 도구이다. 초음파 대역의 진동을 일으키기 위하여 피에조 액츄에이터를 사용하며 액츄에이터의 진동을 가위 날의 세로 방향 진동으로 변환하여 마찰열을 발생시킨다. 초음파 가위의 구동 효율을 높이려면 전원의 전력을 최대한 액츄에이터의 유효 전력으로 전달해야 하는데 전력 전달 효율은 액츄에이터의 공진 주파수에 따라 민감하게 달라진다. 또한 초음파 가위가 동작하는 동안 전체 시스템의 공진 주파수는 계속 변하기 때문에, 공진 주파수를 추종하도록 액츄에이터의 구동 주파수를 계속 바꾸어야 한다. 이 논문에서는 초음파 가위 시스템의 전력 전달 효율을 높이기 위한 방법으로서 임피던스 각을 최소화시키는 방향으로 구동 주파수를 디지털 방식으로 조정하는 주파수 제어 알고리즘을 제안한다. MCU 및 FPGA 기반의 디지털 제어 시스템을 구현하여, 개발 중인 시제품 초음파 가위 기구부와 구동 회로를 사용한 실험을 진행하여 제안한 알고리즘의 유효성을 확인하였다. Ultrasonic scissors are surgical dissecting devices utilizing ultrasonically generated frictional heat for minimally invasive surgery. The devices use a piezoelectric actuator for creating ultrasonic vibrations, which turn into longitudinal oscillations of the blades for cutting tissue. To increase the efficiency of ultrasonic scissors, the driving circuit needs to deliver as much real power to the scissors as possible. The power transfer efficiency of ultrasonic scissors depends highly upon the resonant frequency of the device. Because the resonant frequency of the whole system including load changes while the device is being used, the driving frequency of the device should be also adjusted accordingly. This paper proposes a control system for obtaining high-efficiency power transfer by digitally adjusting the driving frequency in such a way as to minimize the impedance angle of the device. The proposed algorithm was implemented using an MCU and an FPGA and the feasibility was verified through experiments using prototype ultrasonic scissors and driving circuits.

Development of a Master-Slave System for Active Endoscope Using a Multi-DOF Ultrasonic Motor

Takemura, Kenjiro,Harada, Dai,Maeno, Takashi Institute of Control 2002 Transaction on control, automation and systems eng Vol.4 No.1

Endoscopes for industrial and medical fields are expected to have multi degree-of-freedom (DOF) motions. A multi-DOF ultrasonic motor we developed consists of a spherical rotor and a bar-shaped stator, and the rotor rotates around three perpendicular axes using three natural vibration modes of the stator. In this study, a multi-DOF unilateral master-slave system for active endoscope using the multi-DOF ultrasonic motor is developed. The configurations of master and slave arms for active endoscope are similar, so that an operator can easily handle the master-slave system. First, driving characteristics of the multi-DOF ultrasonic motor are measured in order to design the slave arm and its controller. Next, the master arm and the slave arm are designed. Then, the unilateral feedback controller for the master-slave system is developed. Finally, the motion control tests of rotor are conducted. As a result, the possibility of the endoscope is confirmed.