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.

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.

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.

하이브리드 연삭시스템 초음파 공구 개발

김경태(Kyeong Tae Kim),홍윤혁(Yun Hyuck Hong),박경희(Kyung Hee Park),이석우(Seok Woo Lee),최헌종(Hon Zong Choi),최영재(Young Jae Choi) Korean Society for Precision Engineering 2013 한국정밀공학회지 Vol.30 No.11

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 25μm. 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.

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.

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

KenjiroTakemura,DaiHarada,TakashiMaeno 제어·로봇·시스템학회 2002 International Journal of Control, Automation, and Vol.4 No.1

Endoscopes for industrial and medical fields are expected to have multi degree-of-freedom (DOF) motions. A multi-DOFultrasonic 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 meas-ured 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.

Ultrasonic MQL System for Generating Size-controlled Droplets

Axel Lefebure,Seeun Kim,Yunseo Kang,Hajin Park,Jumi Lee,Seohee Jang,Inho Lee,Juhye Shin,Chang Soo Lee,Deuk Kwi Lee,Young Chang Park,Jin Hur,Hyung Jin Kwon,Dongha Shim 한국생산제조학회 2021 한국생산제조학회지 Vol.30 No.5

We present an ultrasonic MQL system for generating size-controlled droplets, engaging the requirement of variations in MQL droplet size depending on the used machining process and material. The proposed system architecture features four series chambers with a different vibrating mesh actuator; it demonstrates that a wide range of material- and machining process-specific lubrication requirements can be achieved by varying the mist atomization rate and droplet diameter. The vibrating-mesh outlet pore sizes were differentiated between 2 to 20 μm and driven by a 100 V peak-to-peak bipolar sinusoidal voltage. The oil with a kinematic viscosity of 8.9 cSt contacted the atomizing surface using an FLDC-configuration. Four-size mists were generated with mean volumetric droplet diameters of 19.1, 21.7, 39.0 and 48.3 μm; their atomization rates vary between 1.3 to 39.4 ml/h. The droplet size control must provide more flexibility for emerging ultrasonic MQL systems with improved lubrication and optimized machine-working performance.

Micro Cylindrical Ultrasonic Motor with Improvised Power and Efficiency

Gyanabrata Sahoo,Baruna Kumar Turuk,Basudeba Behera 한국전기전자재료학회 2023 Transactions on Electrical and Electronic Material Vol.24 No.3

This paper presents a micrometer scale of a bar-type traveling wave ultrasonic motor. The proposed work is based on the cylindrical micro ultrasonic motor which consists of an 8 piezoelectric bar, is very small in size, and has been designed through a Micro-meter scale. It produces a high power/weight ratio, and efficiency is independent of the size of the motor. The different parameters of such motors are studied and analyzed. The motor produces an output power of 5.7 pW. The output torque is 0.28 nN. The produced rotation per minute is 2620 RPM with a preload of 0.98 μN. There is a great demand for high drive power for micro loads in many fields as per their requirement or field of application, such as micro-robots, microsurgery equipment, and MEMS applications.