Investigation of a tilt-wing proof of concept for a high-speed VTOL jet UAV using thrust vectoring for balance

Success of Special operations forces (SOF) missions depends on a high level of situational awareness within sensitive areas of interest, especially when arriving in volatile, sensitive environments. Oftentimes intelligence, surveillance, and reconnaissance (ISR) UAS platforms expand situational awareness for small, clandestine teams for Special Operations; however, there is a demonstrable need for a high-speed, long-range platform capable of point launches and landings to improve outcomes of rapid response missions. This thesis intends to provide the fundamental mechanics of one solution to that platform centered on the premise of a conventional jet UAV being modified into a tilt-wing V/STOL UAV using its existing features.The proof of concept being explored emulates modifying a fast, conventional UAV configuration. That concept possessed a tubular carbon spar that was used as a point of rotation. Motor pods were attached to the wing for the lift system and only used during takeoffs and landings, after which, the propellers were folded away to reduce drag in cruise. Additionally, a thrust vectoring unit was added to the central propulsion system for balance under stall-speeds. The final configuration culminated into a novel tilt-wing VTOL system with the potential to add minimal weight and drag increases to the base configuration. This configuration was then scrutinized for its fundamental challenges to evaluate its effectiveness.Through the research and development of the proof of concept, several milestones were met. Solidworks Flow Simulation (SWFS) was validated for unsteady propeller analyses. Using lessons learned from this validation effort, the tilt-wing concept was found to have the best net lift characteristics over the tilt-rotor after verifying the effects of download experienced in tilt-rotors in SWFS. In fact, the tilt-rotor expressed a net loss in lift of 25% whereas the tilt-wing saw negligible losses. This fully rationalized the tilt-wing as a viable system for the mission profile. After construction and preliminary testing of a prototype, a CG condition was discovered for balancing novel VTOL concepts using separated propulsion systems. This discovery was key in demonstrating the tilt-wing proof of concept where it was shown to execute point launches and landings as intended through simulated testing where the runway footprint of the prototype model was reduced significantly

ヘクサコプターのための耐故障制御と視覚に基づくナビゲーション

学位の種別:課程博士University of Tokyo(東京大学

품질기능전개방법을 이용한 회전익기 개념설계

학위논문(석사)--서울대학교 대학원 :공과대학 기계항공공학부,2019. 8. 이관중.The engineering design of a rotorcraft requires multi-disciplinary decision-making process, often times having to work with incomplete requirements and mission objectives of the complex aerospace systems. In addition, the traditional serial-design approach requires information from one discipline to be passed down for rigorous design iteration. Such design iterations for extremely complicated rotorcraft design demand for excessive resources especially with the absence of formal design methodology. This thesis focuses on the development and integration of a multi-attribute rotorcraft conceptual design framework and the Quality Function Deployment (QFD), a system-engineering-based requirement analysis tool. Rotorcraft design requires complex Multidisciplinary Design Optimization (MDO) having significant effects on the rotorcraft performances simply manipulating interdependent sizing variables. The House of Quality (HOQ) is adopted as part of the QFD process to transform user demands into design quality and prioritize array of design characteristics that impact customer attributes. The proposed design framework also adopts parallel-design approach with the inclusion of higher fidelity analysis in the conceptual design phase. This framework considers various technical aspects including the aerodynamic, structure, propulsion, transmission design, weight and balance, stability and control, noise analysis, and economic analysis. As a system integration of the QFD process, this thesis outlines the proposed conceptual design framework to design a high-altitude mountain rescue vehicle. By employing morphological alternative matrix, and carrying out HOQ analysis, four wing-mounted propellers winged-helicopter configuration with hybridized propulsion system was designed. This result was obtained in conjunction with the HOQ analysis for which, critical design variables identified, were specifically studied to obtain the optimal solution. By adopting the design process, rotorcraft that can hover at 29,100 ft and attain a cruise speed of 185 knots was designed. The proposed design framework provides a central collaborative repository to design aerospace vehicles and provide essential information to initiate preliminary design by the integration of the QFD process.회전익기 설계에는 여러 분야의 의사 결정 프로세스가 필요하며 복잡한 항공 우주 시스템의 불완전한 요구 사항 및 임무 목표를 가지고 설계를 수행한다. 또한 기존의 직렬 설계 방식은, 한 분야의 정보를 전달하여 엄격한 설계 반복을 거쳐야 한다. 하지만 공식적인 설계 방법론이 없고 극도로 복잡한 회전익기 설계에 대한 설계 반복성은 과도한 자원을 요구하기에 이 논문은 시스템 엔지니어링 기반 요구 사항 분석 도구 인 QFD (Quality Function Deployment), 즉 품질기능전개방법을 통한 개념적 설계 프레임워크 개발 및 통합 설계에 중점을 둔다. 회전익기 설계는 복잡한 MDO (Multidisciplinary Design Optimization)를 요구하여 상호 의존적 인 사이징 변수로 인한 성능 변화에 상당한 영향을 미친다. 이를 위해 House of Quality (HOQ)는 사용자 요구를 설계 품질로 변환하고 고객 특성에 영향을 미치는 일련의 설계 특성의 우선 순위를 정하여 초기 설계 단계에서 최대한 자원을 사용하여 설계를 진행한다. 이를 위해 QFD 프로세스로 채택되었고 제시 된 설계 프레임 워크는 개념 설계 단계에서 다양한 분석을 포함하는 병렬 설계 접근법을 채택하여 회전익기를 설계하는 방법을 제시하였다. 또한, 제시된 프레임 워크는 공기 역학, 구조, 추진력, 변속기 설계, 중량 및 균형, 안정성 및 제어, 소음 분석 및 경제적 분석을 비롯한 다양한 기술적 측면을 고려하여 설계 반복과정으로 이어진다. 이 논문은 QFD 과정의 시스템 통합적 검증을 위해 고고도의 구조 헬기를 설계하여 제시 된 개념 설계 프레임 워크를 적용하였다. Morphological Analysis와 다양한 QFD 분석을 수행함으로써, 날개에 장착된 4개의 프로펠러와 하이브리드 추진 시스템을 장착한 winged-helicopter가 설계되었다. 이 결과는 중요한 설계 변수가 확인 된 HOQ 분석과 최적의 솔루션을 얻기 위해 구체적으로 설계 된 결과이다. 제시된 디자인 프로세스를 채택함으로써 29,100ft에서 OGE 호버링이 가능하면서 185knots 의 순항 속도를 달성 할 수 있는 로터 크래프트가 설계되었습니다. 제안 된 설계 프레임 워크는 QFD 프로세스의 통합으로 항공우주비행체를 설계하고 예비 설계를 시작하는 데 필수적인 정보를 제공하는 더욱 효율적이고 효과적인 설계방법으로 적용될 수 있다.I. Introduction . 1 Problem Definition 4 Purpose of Thesis 4 II. Literature Review 6 Decision-Planning Tools in QFD . 9 House of Quality . 10 III. Design Process Methodology . 12 Quality Function Deployment (QFD) 12 Configuration Selection 15 Parallel Design Optimization . 15 Closing Conceptual Design loop 15 IV. Implementation and Results 16 Quality Function Deployment 17 Final Selection 32 Summary of Baseline Prototype. 35 Parallel Design Optimization . 36 Propulsion Group Design . 44 Airframe Design . 51 Ice Protection System Design 57 Weight Estimates 59 Final Design Overview . 62 V. Concluding Remarks . 65 APPENDIX 67 Reference . 86 초 록 . 91Maste

Autonomous Obstacle Collision Avoidance System for UAVs in rescue operations

The Unmanned Aerial Vehicles (UAV) and its applications are growing for both civilian and military purposes. The operability of an UAV proved that some tasks and operations can be done easily and at a good cost-efficiency ratio. Nowadays, an UAV can perform autonomous tasks, by using waypoint mission navigation using a GPS sensor. These autonomous tasks are also called missions. It is very useful to certain UAV applications, such as meteorology, vigilance systems, agriculture, environment mapping and search and rescue operations. One of the biggest problems that an UAV faces is the possibility of collision with other objects in the flight area. This can cause damage to surrounding area structures, humans or the UAV itself. To avoid this, an algorithm was developed and implemented in order to prevent UAV collision with other objects. “Sense and Avoid” algorithm was developed as a system for UAVs to avoid objects in collision course. This algorithm uses a laser distance sensor called LiDAR (Light Detection and Ranging), to detect objects facing the UAV in mid-flights. This light sensor is connected to an on-board hardware, Pixhawk’s flight controller, which interfaces its communications with another hardware: Raspberry Pi. Communications between Ground Control Station or RC controller are made via Wi-Fi telemetry or Radio telemetry. “Sense and Avoid” algorithm has two different modes: “Brake” and “Avoid and Continue”. These modes operate in different controlling methods. “Brake” mode is used to prevent UAV collisions with objects when controlled by a human operator that is using a RC controller. “Avoid and Continue” mode works on UAV’s autonomous modes, avoiding collision with objects in sight and proceeding with the ongoing mission. In this dissertation, some tests were made in order to evaluate the “Sense and Avoid” algorithm’s overall performance. These tests were done in two different environments: A 3D simulated environment and a real outdoor environment. Both modes worked successfully on a simulated 3D environment, and “Brake” mode on a real outdoor, proving its concepts.Os veículos aéreos não tripulados (UAV) e as suas aplicações estão cada vez mais a ser utilizadas para fins civis e militares. A operacionalidade de um UAV provou que algumas tarefas e operações podem ser feitas facilmente e com uma boa relação de custo-benefício. Hoje em dia, um UAV pode executar tarefas autonomamente, usando navegação por waypoints e um sensor de GPS. Essas tarefas autónomas também são designadas de missões. As missões autónomas poderão ser usadas para diversos propósitos, tais como na meteorologia, sistemas de vigilância, agricultura, mapeamento de áreas e operações de busca e salvamento. Um dos maiores problemas que um UAV enfrenta é a possibilidade de colisão com outros objetos na área, podendo causar danos às estruturas envolventes, aos seres humanos ou ao próprio UAV. Para evitar tais ocorrências, foi desenvolvido e implementado um algoritmo para evitar a colisão de um UAV com outros objetos. O algoritmo "Sense and Avoid" foi desenvolvido como um sistema para UAVs de modo a evitar objetos em rota de colisão. Este algoritmo utiliza um sensor de distância a laser chamado LiDAR (Light Detection and Ranging), para detetar objetos que estão em frente do UAV. Este sensor é ligado a um hardware de bordo, a controladora de voo Pixhawk, que realiza as suas comunicações com outro hardware complementar: o Raspberry Pi. As comunicações entre a estação de controlo ou o operador de comando RC são feitas via telemetria Wi-Fi ou telemetria por rádio. O algoritmo "Sense and Avoid" tem dois modos diferentes: o modo "Brake" e modo "Avoid and Continue". Estes modos operam em diferentes métodos de controlo do UAV. O modo "Brake" é usado para evitar colisões com objetos quando controlado via controlador RC por um operador humano. O modo "Avoid and Continue" funciona nos modos de voo autónomos do UAV, evitando colisões com objetos à vista e prosseguindo com a missão em curso. Nesta dissertação, alguns testes foram realizados para avaliar o desempenho geral do algoritmo "Sense and Avoid". Estes testes foram realizados em dois ambientes diferentes: um ambiente de simulação em 3D e um ambiente ao ar livre. Ambos os modos obtiveram funcionaram com sucesso no ambiente de simulação 3D e o mode “Brake” no ambiente real, provando os seus conceitos

Eye in the Sky

This project is separated into two parts: an unmanned aerial vehicle (UAV) and a corresponding capsule. The UAV will be stored in the capsule as the pair is released from underwater and floats to the surface where the capsule will autonomously open and discharge the drone. Following release, the UAV will fly up and record video surveillance of the surrounding area. Finally, the UAV will record the data onto a micro SD card inserted in the monitor that shows the camera’s live feed. The objective is to design, build, test, and finalize a UAV and capsule that meet NUWC’s, the customer, specifications as much as possible. The overarching design for this system consists of a cylindrical capsule with chambers for the drone, electronic controls, controlled air flow, and the tank of compressed air. An Arduino UNO is programmed to trigger the flow of air that pushes the drone out after a certain number of seconds. The UAV is a quadcopter whose arms spread open by a simple spring mechanism once ejected from the capsule but sits linearly while inside the capsule. The capsule has been manufactured from aluminum and the drone uses the Vortex 250 Pro as a base but has been modified to feature the required fold-able arms. Testing has shown that the capsule functions as expected. It floats to the surface, maintains a vertical position, and ejects the UAV after the programmed number of seconds. Testing has also shown that the UAV’s physical body also functions as expected in terms of its arms springing open when no longer constrained within the capsule. Photos and videos have been successfully recorded onto the monitor. The drone’s flight was not tested due to unforeseen and currently unresolved software issues. Overall, if the drone was capable of flight, the team would expect the system to work well as a whole

Aerodynamic force interactions and measurements for micro quadrotors

Unmanned Aerial Vehicles (UAVs) have become mainstream through the success of several large commercial drone manufacturers. Quadrotors have been widely adopted due to their mechanical simplicity, ability to take off from a small area and hover at a fixed location. As these aircraft are increasingly being used in urban environments and indoors their ability to maintain stable flight in the presence of disturbances and nearby obstacles is of growing importance.Understanding the aerodynamics acting in these environments is the first step to improving quadrotor behaviour. This presents a challenge, as to characterise and verify models of the aerodynamic phenomena it is essential to collect numerous consistent experimental data points. On a typical quadrotor the motor response changes as the battery discharges, leading to variation in flight performance. Typically, this is addressed through the use high gain feedback control regulating attitude and position. To overcome this a unique voltage regulator for quadrotor power was developed to maintain constant supply voltage over the quadrotors flight. This enables the quadrotor to produce consistent and repeatable behaviour as the battery discharges.One way to improve the performance of quadrotors flying in constrained environments with limited sensing is to exploit aerodynamic effects for passive control and stability. Ground effect and rotor inflow damping are two effects of interest: ground effect provides a quadratic increase in thrust as a rotor moves closer to the ground; rotor inflow damping acts to resist axial motion by causing a change thrust opposing the movement. By canting the rotors of a quadrotor these effects were brought from the vertical axis into the lateral axis as well. A canted quadrotor flying over a v-shaped channel was modeled and found to exhibit passive stability in position. A demonstrator aircraft and v-shaped channel were tested in a number of configurations and shown to be stable for a channel slope of 10, 15 or 20 degrees with a rotor cant of 15 or 20 degrees.In order to observe more subtle aerodynamic effects, such as wall effect, it is necessary to have a method to measure rotor forces directly during quadrotor flight. Existing force torque sensors are too bulky, heavy, expensive or insensitive. To overcome these limitations a novel force torque sensor was developed that costs less than $50, weighs 3g and is capable of measuring sub mN forces. These sensors utilise an array of micro-electro-mechanical system (MEMS) barometers encapsulated in rubber to measure the strain field imparted by forces acting on the attached load plate. Mounting force torque sensors under the motors of a quadrotor allows the lateral rotor forces to be transmitted through the motor body and measured as torques at the base.Closely related to this, one of the key limitations faced by quadrotors is their inability to directly measure the airspeed of the aircraft. Providing an oncoming wind speed measurement will allow them to compensate for disturbances improving trajectory tracking and gust rejection. Blade flapping and induced drag are aerodynamic phenomena which relate lateral motion to a force acting in opposition to the rotors motion. By measuring this force using a rotor force sensor the airspeed of the aircraft is computed directly using induced drag and rotor blade flapping models. It was found that lateral velocity could be measured for the velocities tested, up to 1.5m/s, and showed a strong linear relationship to ground truth measurements.The work of this thesis has led to the development of: a quadrotor platform for consistent flight behaviour; a passive position-keeping quadrotor; and a novel rotor force sensor for direct measurement of quadrotor airspeed. These technologies open up avenues to improve the flight performance of quadrotors and better understand subtle aerodynamic interactions in flight

Proceedings of the International Micro Air Vehicles Conference and Flight Competition 2017 (IMAV 2017)

The IMAV 2017 conference has been held at ISAE-SUPAERO, Toulouse, France from Sept. 18 to Sept. 21, 2017. More than 250 participants coming from 30 different countries worldwide have presented their latest research activities in the field of drones. 38 papers have been presented during the conference including various topics such as Aerodynamics, Aeroacoustics, Propulsion, Autopilots, Sensors, Communication systems, Mission planning techniques, Artificial Intelligence, Human-machine cooperation as applied to drones

Reference Model for Interoperability of Autonomous Systems

This thesis proposes a reference model to describe the components of an Un-manned Air, Ground, Surface, or Underwater System (UxS), and the use of a single Interoperability Building Block to command, control, and get feedback from such vehicles. The importance and advantages of such a reference model, with a standard nomenclature and taxonomy, is shown. We overview the concepts of interoperability and some efforts to achieve common refer-ence models in other areas. We then present an overview of existing un-manned systems, their history, characteristics, classification, and missions. The concept of Interoperability Building Blocks (IBB) is introduced to describe standards, protocols, data models, and frameworks, and a large set of these are analyzed. A new and powerful reference model for UxS, named RAMP, is proposed, that describes the various components that a UxS may have. It is a hierarchical model with four levels, that describes the vehicle components, the datalink, and the ground segment. The reference model is validated by showing how it can be applied in various projects the author worked on. An example is given on how a single standard was capable of controlling a set of heterogeneous UAVs, USVs, and UGVs

A Summary of NASA Rotary Wing Research: Circa 20082018

The general public may not know that the first A in NASA stands for Aeronautics. If they do know, they will very likely be surprised that in addition to airplanes, the A includes research in helicopters, tiltrotors, and other vehicles adorned with rotors. There is, arguably, no subsonic air vehicle more difficult to accurately analyze than a vehicle with lift-producing rotors. No wonder that NASA has conducted rotary wing research since the days of the NACA and has partnered, since 1965, with the U.S. Army in order to overcome some of the most challenging obstacles to understanding the behavior of these vehicles. Since 2006, NASA rotary wing research has been performed under several different project names [Gorton et al., 2015]: Subsonic Rotary Wing (SRW) (20062012), Rotary Wing (RW) (20122014), and Revolutionary Vertical Lift Technology (RVLT) (2014present). In 2009, the SRW Project published a report that assessed the status of NASA rotorcraft research; in particular, the predictive capability of NASA rotorcraft tools was addressed for a number of technical disciplines. A brief history of NASA rotorcraft research through 2009 was also provided [Yamauchi and Young, 2009]. Gorton et al. [2015] describes the system studies during 20092011 that informed the SRW/RW/RVLT project investment prioritization and organization. The authors also provided the status of research in the RW Project in engines, drive systems, aeromechanics, and impact dynamics as related to structural dynamics of vertical lift vehicles. Since 2009, the focus of research has shifted from large civil VTOL transports, to environmentally clean aircraft, to electrified VTOL aircraft for the urban air mobility (UAM) market. The changing focus of rotorcraft research has been a reflection of the evolving strategic direction of the NASA Aeronautics Research Mission Directorate (ARMD). By 2014, the project had been renamed the Revolutionary Vertical Lift Technology Project. In response to the 2014 NASA Strategic Plan, ARMD developed six Strategic Thrusts. Strategic Thrust 3B was defined as the Ultra-Efficient Commercial VehiclesVertical Lift Aircraft. Hochstetler et al. [2017] uses Thrust 3B as an example for developing metrics usable by ARMD to measure the effectiveness of each of the Strategic Thrusts. The authors provide near-, mid-, and long-term outcomes for Thrust 3B with corresponding benefits and capabilities. The importance of VTOL research, especially with the rapidly expanding UAM market, eventually resulted in a new Strategic Thrust (to begin in 2020): Thrust 4Safe, Quiet, and Affordable Vertical Lift Air Vehicles. The underlying rotary wing analysis tools used by NASA are still applicable to traditional rotorcraft and have been expanded in capability to accommodate the growing number of VTOL configurations designed for UAM. The top-level goal of the RVLT Project remains unchanged since 2006: Develop and validate tools, technologies and concepts to overcome key barriers for vertical lift vehicles. In 2019, NASA rotary wing/VTOL research has never been more important for supporting new aircraft and advancements in technology. 2 A decade is a reasonable interval to pause and take stock of progress and accomplishments. In 10 years, digital technology has propelled progress in computational efficiency by orders of magnitude and expanded capabilities in measurement techniques. The purpose of this report is to provide a compilation of the NASA rotary wing research from ~2008 to ~2018. Brief summaries of publications from NASA, NASA-funded, and NASA-supported research are provided in 12 chapters: Acoustics, Aeromechanics, Computational Fluid Dynamics (External Flow), Experimental Methods, Flight Dynamics and Control, Drive Systems, Engines, Crashworthiness, Icing, Structures and Materials, Conceptual Design and System Analysis, and Mars Helicopter. We hope this report serves as a useful reference for future NASA vertical lift researchers

Autonomous Vehicles

This edited volume, Autonomous Vehicles, is a collection of reviewed and relevant research chapters, offering a comprehensive overview of recent developments in the field of vehicle autonomy. The book comprises nine chapters authored by various researchers and edited by an expert active in the field of study. All chapters are complete in itself but united under a common research study topic. This publication aims to provide a thorough overview of the latest research efforts by international authors, open new possible research paths for further novel developments, and to inspire the younger generations into pursuing relevant academic studies and professional careers within the autonomous vehicle field