미세 물체 수송을 위한 니티놀 마이크로 로봇

학위논문(석사) -- 서울대학교대학원 : 공과대학 기계공학과, 2021.8. 안성훈.A micro-robot is an attractive tool that performs micro-scale tasks within the system by remote control. Most micro-robots are driven by an external force and its characteristic differs according to the type of the external force. Therefore, micro-robots have been developed to utilize the type of external force suitable for their respective application fields. Among various external forces, a light-driven micro-robot has superior controllability in terms of precision and regionality. Recently, lots of studies have been conducted on micro-robot for performing micro-scale tasks in bio-medical fields such as drug transport, surgery and diagnosis. Especially in micro-object transportation, since sophisticated control is required, a light-driven micro-robot which has excellent controllability is advantageous. Micro-robots for transportation so far have focused on force, speed and control, but a few of them have a function of holding objects to avoid object loss. Our micro-object transportation Ni-Ti structure robot(MTNs) not only has sufficient thrust force and speed but also has the capability of holding objects and physically separating them from external systems, thus demonstrating the advantage of excellent transport stability and controllability. It can be fabricated and controlled automatically by a vision-guided laser control system. In consideration of mass production, we designed the micro-robot so that the fabrication process has low cost in terms of time, price and labor, and can be operated by commercial equipment. The newly designed transport micro-robot, which displays holding capability and enhanced control, can be used as an actuator in lab-on-a-chip testing.마이크로 로봇은 원격 제어를 통해 시스템 내에서 미세작업을 수행할 수 있는 도구로써, 약물 수송, 수술, 진단과 같은 생물 의학 분야에서 많 은 연구가 진행되고 있다. 마이크로 로봇은 외력을 통해 에너지를 공급 받고, 제어되므로, 이용하는 외력의 종류에 따라 구동 특성이 달라진다. 여러 외력 중 광 구동형 마이크로 로봇은 정밀하고 국소적인 제어가 가 능하다는 장점을 가지고 있다. 그러므로 정교한 제어가 필요한 마이크로 물체 운반 작업에 광구동형 마이크로 로봇이 적합하다. 지금까지 운송용 마이크로 로봇은 힘, 속도 및 제어에 중점을 두었지만, 물체 유실을 방 지하기 위해 물체를 잡는 기능을 가진 로봇은 거의 없습니다. 우리가 개 발한 미세 물체 수송 Ni-Ti 마이크로 로봇은 충분한 추진력과 속도를 가질 뿐만 아니라 운반 목표 물체를 포획한 상태로 외부 시스템과 격리 한 상태로 운반할 수 있는 능력을 갖추고 있어 우수한 수송 안정성과 제 어 편의성 등 이점을 보인다. 본 로봇은 비전 유도 레이저 제어 시스템에 의해 자동으로 제작이 가능 하다. 양산을 고려하여 상용장비 만으로 제작 공정을 구성하였으며, 시 간, 가격 그리고 노동력 측면에서 저렴하도록 마이크로 로봇을 설계하였 다. 포획 능력과 향상된 제어 기능을 가진 본 로봇은 랩 온어 칩 테스트 에서 액추에이터로 사용될 수 있다.Chapter 1. Introduction 1 1.1. Reviews on micro robots for bio-medical applications 1 1.2. Reviews on micro transportation 3 1.3. Reviews on micro robots using external forces 4 1.4. Reviews on light-driven Ni-Ti micro robots 5 1.5. Purpose of research 7 Chapter 2. Ni-Ti Unit 8 2.1. Actuation mechanism 8 2.2. Fabrication of Ni-Ti unit 10 Chapter 3. Fabrication process 11 3.1. Overview of fabrication process 11 3.2. Formation morphing control 13 3.2.1. Single unit control 13 3.2.2. Vision-guided laser control system 15 3.2.3. Control strategy 17 3.3. Bonding process 19 3.3.1. Adhesion applying using EHD 19 3.3.2. Adhesion applying using microstage 22 Chapter 4. Experiment and Application 23 4.1. Force measurement experiment 23 4.2. Energy efficiency comparison 25 4.3. Functionality of transportation 27 Chapter 5. Conclusion 29 Bibliography 30 Abstract in Korean 35석

Magnetic motion control and planning of untethered soft grippers using ultrasound image feedback

Soft miniaturized untethered grippers can be used to manipulate and transport biological material in unstructured and tortuous environments. Previous studies on control of soft miniaturized grippers employed cameras and optical images as a feedback modality. However, the use of cameras might be unsuitable for localizing miniaturized agents that navigate within the human body. In this paper, we demonstrate the wireless magnetic motion control and planning of soft untethered grippers using feedback extracted from B-mode ultrasound images. Results show that our system employing ultrasound images can be used to control the miniaturized grippers with an average tracking error of 0.4±0.13 mm without payload and 0.36±0.05 mm when the agent performs a transportation task with a payload. The proposed ultrasound feedback magnetic control system demonstrates the ability to control miniaturized grippers in situations where visual feedback cannot be provided via cameras

Control of untethered soft grippers for pick-and-place tasks

In order to handle complex tasks in hard-toreach environments, small-scale robots have to possess suitable dexterous and untethered control capabilities. The fabrication and manipulation of soft small- scale grippers complying to these requirements is now made possible by advances in material science and robotics. In this paper, we use soft small-scale grippers to demonstrate pick-and-place tasks. The precise remote control is obtained by altering both the magnetic field gradient and the temperature in the workspace. This allows us to regulate the position and grasping configuration of the soft thermally-responsive hydrogel-nanoparticle composite magnetic grippers. The magnetic closed-loop control achieves precise localization with an average region-of-convergence of the gripper of 0.12±0.05 mm. The micro-sized payload can be placed with a positioning error of 0.57±0.33 mm. The soft grippers move with an average velocity of 0.72±0.13 mm/s without a micro-sized payload, and at 1.09±0.07 mm/s with a micro-sized payloa

Microrobots for wafer scale microfactory: design fabrication integration and control.

Future assembly technologies will involve higher automation levels, in order to satisfy increased micro scale or nano scale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to micro-electronics and MEMS industries, but less so in nanotechnology. With the bloom of nanotechnology ever since the 1990s, newly designed products with new materials, coatings and nanoparticles are gradually entering everyone’s life, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than with top-down robotic assembly. This is due to considerations of volume handling of large quantities of components, and the high cost associated to top-down manipulation with the required precision. However, the bottom-up manufacturing methods have certain limitations, such as components need to have pre-define shapes and surface coatings, and the number of assembly components is limited to very few. For example, in the case of self-assembly of nano-cubes with origami design, post-assembly manipulation of cubes in large quantities and cost-efficiency is still challenging. In this thesis, we envision a new paradigm for nano scale assembly, realized with the help of a wafer-scale microfactory containing large numbers of MEMS microrobots. These robots will work together to enhance the throughput of the factory, while their cost will be reduced when compared to conventional nano positioners. To fulfill the microfactory vision, numerous challenges related to design, power, control and nanoscale task completion by these microrobots must be overcome. In this work, we study three types of microrobots for the microfactory: a world’s first laser-driven micrometer-size locomotor called ChevBot，a stationary millimeter-size robotic arm, called Solid Articulated Four Axes Microrobot (sAFAM), and a light-powered centimeter-size crawler microrobot called SolarPede. The ChevBot can perform autonomous navigation and positioning on a dry surface with the guidance of a laser beam. The sAFAM has been designed to perform nano positioning in four degrees of freedom, and nanoscale tasks such as indentation, and manipulation. And the SolarPede serves as a mobile workspace or transporter in the microfactory environment