Untethered Microrobots of the Rolling, Jumping & Flying kinds

In this dissertation we study microrobot design for three modes of locomotion, namely rolling, jumping, and flying. This work covers power electronics, actuator and mechanical transmission design for these types of microrobots along with power source selection. Though interesting, we do not cover the sensors, controllers/computers, communications and useful payloads for these bots. This remains a topic for future work. Piezoelectric and electrostatic actuators generally have been the actuators of choice for researchers working in microrobotics, since conventional electromagnetic motor designs don't scale down well. Here we design an electromagnetic actuator in a way that significantly reduces its scaling down disadvantages, while still retaining its original advantages. This has enabled us to achieve untethered operation for our bots, which is one of the coveted goals for researchers working in this domain. Though untethered rolling and jumping is demonstrated, the untethered flying bot reported in this dissertation remains underpowered and doesn't take flight yet. First a micro-ratcheting mechanism is developed as a means to convert small periodic motions of actuators to continuous rotational motion. A supercapacitor, a fixed frequency H-bridge, and a low-voltage electromagnetic actuator is then used to drive this micro-ratchet to achieve untethered rolling motion for 8 seconds at 27mm/s. At 130mg mass, this is the lightest and fastest untethered rolling microrobot reported yet. The same continuous rotation mechanism developed for the rolling bot is then used to load a spring in an energy storage mechanism that can then release the stored energy rapidly and passively, via use of magnets, after the stored energy crosses a certain threshold. In this case, the continuous rotation mechanism is driven using laser-powered photovoltaic cells and untethered jumping up to heights of 8mm is demonstrated. At 75mg mass, it is the lightest untethered jumping microrobot with onboard power source. Next, a highly efficient resonant low-voltage electromagnetic actuator is developed to generate insect-like flapping wing motion. It is demonstrated to produce 90% of its weight in lift. Further light-weight and power-efficient power electronics are developed to power this actuator using laser-powered photovoltaic cells. The designed power electronics are an order of magnitude lighter and two orders of magnitude more efficient than all other power electronics units reported yet for flying microrobots. While sufficient lift for flight is not achieved, due to the actuator being underpowered because of power source overheating, untethered flapping wing motion is demonstrated. To provide inspiration to future generations of microroboticists, a fruit fly scale flapping winged robot is developed. At 0.7mg mass, even though tethered, it is the lightest and smallest bot to demonstrate flapping wing kinematics

ポリマー微細加工によって作成される羽ばたき翼微小飛行体のデザインウィンドウ探索法による開発

The specific flight mechanisms of insects like hovering and maneuverability along with their tiny size nature grasp the attention of many researchers across the globe to utilize the phenomena for the development of biomimetic flapping wing air vehicles which can be used in the wide areas like hazardous environment exploration, rescue, agriculture, pipeline inspection, and earthquake or tsunami disaster management, etc where human access is difficult. Consequently, many researchers have developed flapping wing air vehicles ranging from macro scale to the nanoscale (the largest dimension should be less than or equal to 10 cm) i.e., flapping-wing nano air vehicles (FWNAVs). The research on insect-inspired FWNAVs indicates that FWNAVs generally consist of micro transmission for getting desired flapping motion, a pair of micro wings, an actuator for the power source, and a supporting frame to support the overall structure. Recently, FWNAVs up to a size of 30 mm have been developed based on the insect’s size. However, the evolution of insects indicates that the size of ultimate small insects is about 1 mm. The further miniaturization of current FWNAVs is difficult because of the large assembly of components and complicated mechanical transmission mechanism. Though, there are mainly two difficulties to successfully developing FWNAVs at the scale of mm-size. The first is the manufacturing difficulty because of the very small structure to realize the wing’s complicated motions. The second is the design difficulty because of multisystem and involvement of coupled Multiphysics like fluid-structure interaction (FSI) design. Along with these difficulties other difficulty includes enough lift to drag ratio for hover and thrust for forwarding flight motion due to fluid mechanics at low Reynolds no (Re < 3000). These difficulties can be overcome by developing FWNAVs based on a design window search methodology where a design solution can be obtained for the design problem satisfying all the design requirements. Further fabricating the FWNAVs using advanced engineering technologies such as microelectromechanical systems (MEMS) technologies which seem to be suitable for mm-size prototypes. Computational analysis and design can be utilized for finding the design window search for FWNAVs. The finite element method (FEM) has been the standard choice as a numerical tool for performing the simulation of Multisystem, because of its capabilities to analyze the geometries of complex shapes, detailed analysis of coupled effect, boundary, and initial conditions. The purpose of this study is to develop 10 mm insect-inspired FWNAV using a 2.5-dimensional structure novel approach, iterative design window search methodology, and polymer micromachining. The proposed FWNAV consists of a micro transmission with a support frame, a micro wing, and a piezoelectric bimorph actuator. The novelty of this research includes, (1) the novel transmission mechanism using two parallel elastic hinges based on geometrically nonlinear bending deformation that produces a large rotational displacement from a small translational displacement, (2) the complete 2.5-D structure which can be fabricated using the polymer micromachining technique without any post-assembly (3) the novel design approach or iterative design window (DW) search method using the advanced computational analysis and design. The advantage of the proposed FWNAV over other FWNAVs includes the lowest energy loss due to no post assembly (friction loss is less), reducing total weight, ease in miniaturization, and enough performance without resonance mechanism. In order to develop the proposed FWNAV, firstly I have designed micro transmissions with a support frame and micro wing and later I have designed FWNAV which has been further miniaturized to design 10mm FWNAV using the iterative DW search method. I have also estimated fatigue life arising due to random cyclic stress, which is mostly ignored by the researchers. Computational flight performance of the proposed FWNAV has been evaluated using Multiphysics coupled analysis i.e., fluid-structure interaction analysis where governing equilibrium equation of motion of micro wing and surrounding airflow has been directly solved by finite element methods. The computational flight performance indicates that mean lift force is comparable to the weight of FWNAV which provides that the proposed FWNAV can lift off. The polymer micromachining has been demonstrated by fabricating the transmission which is a key and central component of FWNAV which indicates the feasibility of polymer micromachining for the development of 10 mm FWNAV. Thus, 10 mm flyable FWNAV can be developed which has enough fatigue life.九州工業大学博士学位論文 学位記番号：情工博甲第369号 学位授与年月日：令和4年9月26日1 General Introduction|2 Proposal of 2.5-dimensional one wing transmission for flapping-wing nano air vehicle|3 Iterative design window search for polymer micromachined flapping-wing nano air vehicle|4 Computational flight performance of flapping wing nano air vehicles using fluid-structure interaction analysis|5 Development of flapping-wing nano air vehicle|6 General Conclusion九州工業大学令和4年

Advances in Bio-Inspired Robots

This book covers three major topics, specifically Biomimetic Robot Design, Mechanical System Design from Bio-Inspiration, and Bio-Inspired Analysis on A Mechanical System. The Biomimetic Robot Design part introduces research on flexible jumping robots, snake robots, and small flying robots, while the Mechanical System Design from Bio-Inspiration part introduces Bioinspired Divide-and-Conquer Design Methodology, Modular Cable-Driven Human-Like Robotic Arm andWall-Climbing Robot. Finally, in the Bio-Inspired Analysis on A Mechanical System part, research contents on the control strategy of Surgical Assistant Robot, modeling of Underwater Thruster, and optimization of Humanoid Robot are introduced

Design Method of a Multiport MIMO Antenna on a Bilaterally Symmetric Conductor Using Characteristic Mode Theory

학위논문 (석사)-- 서울대학교 대학원 공과대학 전기·정보공학부, 2017. 8. 남상욱.본 논문에서는 특성 모드 이론에 기반한 다중 포트 MIMO 안테나 설계 방법을 제안한다. 보다 구체적으로는, 하나의 대칭 축이 있는 도체를 다중 포트 MIMO 안테나로 설계하는 방법론을 제시한다. MIMO 통신 기술의 발달로 정해진 공간내에서의 다중의 독립적인 안테나 설계를 필요로 한다. 특성 모드 이론은 정해진 도체에서의 직교하는 공진 모드들을 제공해주고, 이와 모드 디커플링 네트워크를 이용하면 주어진 도체를 이용한 MIMO 안테나 설계가 가능하다고 알려져 있다. 하지만, 안테나의 수가 늘어남에 따라 모드 디커플링 네트워크는 복잡한 설계가 요구된다. 이전에는 이를 보다 간한하게 구현하기 위해 상하좌우대칭 도체에서의 MIMO 안테나의 설계가 요구되었다. 본 논문에서는 좌우대칭 도체에서의 보다 간단한 다중 포트 MIMO 안테나 설계 방법을 제안한다. 보다 자세하게는, 간단한 모드 디커플링 네트워크 구현은 특성 모드를 급전하는 커플링 요소의 설계에 의존적이기에, 이에 대한 위치 및 모양에 대한 설계 방식을 제안한다. 제안된 설계 방법론을 검증하기 위해서, 2.4GHz- ISM 대역에서 동작하는 생체모방형 드론에 사용되는 삼중 안테나를 제작 및 측정하였다. 이 안테나는 50 mm 61.5 mm 10 mm 의 크기를 가지며, FR-4 단층 기판을 이용하여 설계되었다. 측정 결과, mutual coupling은 -20 dB 이하로 낮은 커플링을 제공하였고, 안테나 패턴 간의 상관도를 나타내는 지표인 envelope correlation coefficient는 0.001보다 낮은 값을 제공하였기에 MIMO 통신용으로써 적합함을 보였다.제 1 장 서론 1 제 2 장 특성 모드 이론 4 제 1 절 특성 모드 이론의 개요 4 제 2 절 특성 전류 상관도 6 제 3 절 슬롯 형태의 유도성 커플링 분석 8 제 3 장 좌우대칭 도체에서의 제안된 설계 방법 11 제 1 절 다른 군의 특성 모드를 사용하는 안테나 설계 12 제 2 절 같은 군의 다른 특성 모드를 사용하는 안테나 설계 13 제 3 절 제안된 다중 포트 MIMO 안테나의 시스템 구성 18 제 4 장 예시 생체 모방의 벌레 모양 MIMO 안테나 20 제 1 절 벌레 모양 도체의 특성 모드 분석 21 제 2 절 제안된 방식에 기반한 ICE 설계 22 제 3 절 MDN을 포함하는 시스템적인 설계 25 제 4 절 측정 및 결과 27 제 5 장 결론 31 부록 34 참고문헌 37 Abstract 40Maste

Feature Papers of Drones - Volume I

[EN] The present book is divided into two volumes (Volume I: articles 1–23, and Volume II: articles 24–54) which compile the articles and communications submitted to the Topical Collection ”Feature Papers of Drones” during the years 2020 to 2022 describing novel or new cutting-edge designs, developments, and/or applications of unmanned vehicles (drones). Articles 1–8 are devoted to the developments of drone design, where new concepts and modeling strategies as well as effective designs that improve drone stability and autonomy are introduced. Articles 9–16 focus on the communication aspects of drones as effective strategies for smooth deployment and efficient functioning are required. Therefore, several developments that aim to optimize performance and security are presented. In this regard, one of the most directly related topics is drone swarms, not only in terms of communication but also human-swarm interaction and their applications for science missions, surveillance, and disaster rescue operations. To conclude with the volume I related to drone improvements, articles 17–23 discusses the advancements associated with autonomous navigation, obstacle avoidance, and enhanced flight plannin