Magnetic microrobot and its application in a microfluidic system

AbstractThis paper researches the design and control method of a microrobot in a microfluidic system by electromagnetic field. The microrobot can move along the microchannel to a required position, and by changing the magnetic torque, the microrobot can also rotate in the microfluidic chip. As an application of the microrobot, it is used as a mobile micromixer to mix two solutions in the microfluidic chip, and the experimental results verify its effectiveness

Dry Surface Micromanipulation Using An Untethered And Magnetic Microrobot

Precise micromanipulation tasks are typically performed using micromanipulators that require an accessible workspace to reach components. However, many applications have inaccessible or require sealed workspaces. This paper presents a novel magnetically-guided, and untethered, actuation method for precise and accurate positioning of microcomponents on dry surface within a remote workspace using a magnetic microrobot. By use of an oscillatory and uniform magnetic field, the magnetic microrobot can traverse on a dry surface with fine step size and accurate open-loop vector following, 3% and 2% of its body-length, respectively (step size of 7 μm). While maintaining precise positioning capability, the microrobot can manipulate and carry other microcomponents on the dry surface using direct pushing or grasping using various attachments, respectively. We demonstrate and characterize the untethered micromanipulation capabilities of this method using a 3 mm cubic microrobot for us

Robotic metamorphosis by origami exoskeletons

Changing the inherent physical capabilities of robots by metamorphosis has been a long-standing goal of engineers. However, this task is challenging because of physical constraints in the robot body, each component of which has a defined functionality. To date, self-reconfiguring robots have limitations in their on-site extensibility because of the large scale of today’s unit modules and the complex administration of their coordination, which relies heavily on on-board electronic components. We present an approach to extending and changing the capabilities of a robot by enabling metamorphosis using self-folding origami “exoskeletons.” We show how a cubical magnet “robot” can be remotely moved using a controllable magnetic field and hierarchically develop different morphologies by interfacing with different origami exoskeletons. Activated by heat, each exoskeleton is self-folded from a rectangular sheet, extending the capabilities of the initial robot, such as enabling the manipulation of objects or locomotion on the ground, water, or air. Activated by water, the exoskeletons can be removed and are interchangeable. Thus, the system represents an end-to-end (re)cycle. We also present several robot and exoskeleton designs, devices, and experiments with robot metamorphosis using exoskeletons

Kendi kendini konfigüre edebilen bir sistemdeki tekil modül için dış manyetik eyleyiciler kullanılarak hareket mekanizmasının geliştirilmesi

In microrobotics field, self-reconfigurable modular robots (SRMRs) offer several advantages including adaptation to uneven environments, the capability of handling various sets of tasks, and continuous operation in the case of a malfunction of a single module. The current research direction in self-reconfigurable robotic systems is towards reaching million level number of modules working in coherence by means of locomotion, self-reconfiguration, and information flow. This research direction comes with new challenges such as miniaturizing the modules. One should consider looking for alternative ways of locomotion and self-reconfiguration when dealing with SRMRs having million level number of modules. Externally actuating the modules can be a good alternative to micro SRMRs. In this study, we developed a novel motion mechanism for a single module in a micro SRMR system by using external magnetic actuators. An assembly of elastic microtubes and permanent magnets is attached inside a cube-shaped module and periodic motion of the assembly is applied. The motion of a single microtube with permanent magnets inside is generated by using COMSOL Multiphysics software. The results of the simulations are compared with theoretical values to validate the motion mechanism that is introduced in the study.Mikro robotik alanında, kendi kendini konfigüre edebilen modüler robotlar (KKMR) düzensiz çevreye uyum sağlayabilme, birçok değişken görevi yerine getirebilme ve tekil modüllerin arızalanması durumunda operasyonu sürdürebilme gibi avantajlar sunmaktadır. Kendi kendini konfigüre edebilen robotik sistemlerdeki son güncel araştırmalar, milyon seviyesinde modül sayısına sahip sistemlerin hareket, kendi kendini konfigüre etme ve bilgi akışı gözetilerek geliştirilmesi yönündedir. Bu araştırma yönelimi beraberinde modüllerin minyatürleştirilmesi gibi sınamalar getirmektedir. Milyon mertebesinde modüle sahip bir KKMR sistemi göz önünde bulundurulduğunda, hareket ve kendi kendini konfigüre etme mekanizmaları için alternatif metotların araştırılması gerekmektedir. Modüllerin dış eyleyiciler ile harekete geçirilmesi mikro KKMR sistemleri için iyi bir seçenek oluşturmaktadır. Bu çalışmada mikro KKMR sistemindeki tekil bir modül için dış manyetik eyleyiciler kullanılarak özgün bir hareket mekanizması geliştirilmiştir. Esnek mikro tüp ve kalıcı mıknatıslardan oluşan bir yapı modülün içerisine yerleştirilmiş ve yapıya periyodik bir hareket uygulanmıştır. Tekil bir mikro tüp kalıcı mıknatıs yapısının hareketi COMSOL Multiphysics yazılımı kullanılarak canlandırılmıştır. Simülasyon sonuçları teorik değerler ile karşılaştırılarak önerilen hareket mekanizmasının doğrulaması gerçekleştirilmiştir

The Fabrication and Evaluation of Selective Bacterial Attachment Device Using Laminar Flow

학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2014. 8. 서종모.현재 화학적 암 치료에 사용되는 항암제는 정상세포에도 작용해 부작용을 일으키며, 또한 전이된 암세포를 효과적으로 치료하기 위하여 특정 병소에 표적화된 약물전달시스템(Drug delivery systemDDS) 개발이 필요하다. 본 연구는 살모넬라 박테리아를 약물 전달체에 선택적으로 부착시켜 이동성을 높인 박테리아 부착 약물 전달 시스템 제작에 관한 것이다. 박테리아의 이동성을 이용한 약물전달시스템은 외부 전력이 필요 없으며, 특히 살모넬라(S. typhimurium)의 경우 특정 암세포에 대한 주화성이 있어서 표적화된 DDS를 개발하기에 적합하다. 본 연구에서는 폴리카프로락톤 (poly-ε-carprolactonePCL)으로 제작한 약물을 탑재할 수 있는 정육각형 마이크로 챔버와 유전자변형을 통해 형광발현을 하며 약독화된 살모넬라(SHJ2037)를 이용하여 DDS를 제작하였다. DDS의 효율적인 이동을 위해 마이크로 챔버에 선택적으로 살모넬라를 부착해야 한다. 이를 위해 본 연구에서는 마이크로 챔버를 포획할 수 있는 트랩퍼라는 구조체를 제작하고, 이용하여 살모넬라를 마이크로 챔버에 선택적으로 부착시켜 보았다. 포획된 전달체 표면은 트랩퍼가 물리적 장벽으로 작동하여 살모넬라가 트랩퍼에 포획된 전달체 표면 중 일부 표면에만 부착하게 함으로써 박테리아의 구조적인 선택적 부착이 가능하게 하였다. 즉, 박테리아는 층류를 따라 정렬되어 이동하게 되고, 트랩퍼의 반대편인 개방된 마이크로 챔버 표면에 부착된다. 실험 결과, 트랩퍼는 60% 이상의 마이크로 챔버 포획률을 보였다. 형광 발현된 살모넬라를 주입한 후, 마이크로 챔버 표면의 형광 변화를 통해 살모넬라가 마이크로 챔버에 수 초 내에 부착된 것을 관찰하였고, 전계방출 주사형 전자현미경(Field Emission Scanning Electron MicroscopeFE-SEM)을 통해 마이크로 챔버의 표면에 다량의 박테리아가 선택적으로 부착되었음을 확인하였다. 본 연구에서 제작한 박테리아 부착 DDS의 속도는 약 67 um/min 정도이며, 이는 기존의 박테리아를 이용한 DDS 속도의 2배 이상 이다. 본 논문에서 제안한 선택적인 박테리아 부착 기술은 기존의 DDS의 이동, 전달속도 개선을 위한 기술로써, 실제 사용 가능한 박테리아 부착 DDS의 개발에 도움이 될 것이다.제 1 장 서 론 1 제 1 절 연구의 배경 1 제 2 절 암 치료용 표적지향 약물전달 시스템 4 제 3 절 박테리아를 이용한 마이크로 로봇 6 제 4 절 박테리아 부착 연구 10 제 5 절 박테리아 이동성 연구 13 제 2 장 설계 및 물질 16 제 1 절 마이크로 플루이딕 장치 시뮬레이션 18 제 2 절 마이크로 플루이딕 장치 설계 20 제 3 절 마이크로 플루이딕 장치 공정 24 제 4 절 박테리아 배양 26 제 5 절 마이크로 챔버의 그물 구조 27 제 3 장 실험 방법 28 제 4 장 실험 결과 30 제 1 절 마이크로 챔버 포획 30 제 2 절 박테리아 선택적 부착 32 제 3 절 유체 흐름 분석 35 제 4 절 박테리아 부착 시간 36 제 5 절 박테리아-마이크로 챔버 이동 속도 37 제 5 장 결 론 39 참고 문헌 40 Abstract 44Maste

An overview of multiple DoF magnetic actuated micro-robots.

International audienceThis paper reviews the state of the art of untethered, wirelessly actuated and controlled micro-robots. Research for such tools is being increasingly pursued to provide solutions for medical, biological and industrial applications. Indeed, due to their small size they o er both high velocity, and accessibility to tiny and clustered environments. These systems could be used for in vitro tasks on lab-on-chips in order to push and/or sort biological cells, or for in vivo tasks like minimally invasive surgery and could also be used in the micro-assembly of microcomponents. However, there are many constraints to actuating, manufacturing and controlling micro-robots, such as the impracticability of on-board sensors and actuators, common hysteresis phenomena and nonlinear behavior in the environment, and the high susceptibility to slight variations in the atmosphere like tiny dust or humidity. In this work, the major challenges that must be addressed are reviewed and some of the best performing multiple DoF micro-robots sized from tens to hundreds m are presented. The di erent magnetic micro-robot platforms are presented and compared. The actuation method as well as the control strategies are analyzed. The reviewed magnetic micro-robots highlight the ability of wireless actuation and show that high velocities can be reached. However, major issues on actuation and control must be overcome in order to perform complex micro-manipulation tasks

State Estimation of an Acoustic Bubble-Powered Microswimmer from Ultrasound Imaging Data

Tiny and untethered robots can navigate into narrow blood arteries and in vivo tissues. Such a revolutionary device brings the possibility of delivering drugs to a specific target and medical diagnosis of diseases that may not be feasible with conventional treatment and diagnosis. Current medical micro-robot technology uses externally-generated magnetic fields. The actuation technology, although external to the micro-robot, is expensive and bulky. There is also always a risk of damaging human tissues with this technique. A promising recent technology uses acoustic waves as a power source for a micro swimming robot. An acoustic power source is extremely small compared to a magnetic field power source and there is a very little risk of any damage to the tissues during the micro-robot actuation. This thesis presents dynamic modeling and state estimation of a novel underwater swimming micro-robot that is powered through oscillations of gas bubbles trapped inside the micro-robot. The rectangular shaped, which is made of photoresist, has the dimensions of 950 μm × 460 µm × 340 μm. The motion is produced by the oscillations of gaseous bubbles trapped in the micro-tubes. Primarily acoustic waves induce oscillations at a certain frequency and thus are used as a propulsion mechanism to realize 3 degree-of-freedom swimming motion. Ultrasound imaging is proposed to sense the swimming motion of the micro-robot. The main focus of the thesis is on the development of an estimator that detects swimming motion of the micro-robot from ultrasound imaging data. A new class of nonlinear state estimation method, called state-dependent coefficient (SDC) estimator, is implemented to improve the accuracy of micro-robot state estimation. The estimator is also used to predict rotation of the robot, which cannot be measured by ultrasound imaging due to the robot’s extremely small size. Experiments and simulations were carried out to verify the accuracy of the estimator and the performance of the estimator coupled with a closed-loop controller. A dynamic model that captures the acoustic actuation was also developed. The model is used in the SDC estimator and was also used to develop a nonlinear control law that tracks a desired swimming motion. The model includes a switching mechanism that was designed to produce bidirectional swimming motion (e.g., left turn and right turn). Each channel that holds the gas bubbles can produce only unidirectional movement. The mechanism switches between counteracting tubes to produce bidirectional movement. The input switch mechanism was demonstrated in a simulation study of the micro-swimmer