8 research outputs found
UAV or Drones for Remote Sensing Applications in GPS/GNSS Enabled and GPS/GNSS Denied Environments
The design of novel UAV systems and the use of UAV platforms integrated with robotic sensing and imaging techniques, as well as the development of processing workflows and the capacity of ultra-high temporal and spatial resolution data, have enabled a rapid uptake of UAVs and drones across several industries and application domains.This book provides a forum for high-quality peer-reviewed papers that broaden awareness and understanding of single- and multiple-UAV developments for remote sensing applications, and associated developments in sensor technology, data processing and communications, and UAV system design and sensing capabilities in GPS-enabled and, more broadly, Global Navigation Satellite System (GNSS)-enabled and GPS/GNSS-denied environments.Contributions include:UAV-based photogrammetry, laser scanning, multispectral imaging, hyperspectral imaging, and thermal imaging;UAV sensor applications; spatial ecology; pest detection; reef; forestry; volcanology; precision agriculture wildlife species tracking; search and rescue; target tracking; atmosphere monitoring; chemical, biological, and natural disaster phenomena; fire prevention, flood prevention; volcanic monitoring; pollution monitoring; microclimates; and land use;Wildlife and target detection and recognition from UAV imagery using deep learning and machine learning techniques;UAV-based change detection
Safe and accurate MAV Control, navigation and manipulation
This work focuses on the problem of precise, aggressive and safe Micro Aerial Vehicle (MAV) navigation as well as deployment in applications which require physical interaction with the environment. To address these issues, we propose three different MAV model based control algorithms that rely on the concept of receding horizon control. As a starting point, we present a computationally cheap algorithm which utilizes an approximate linear model of the system around hover and is thus maximally accurate for slow reference maneuvers. Aiming at overcoming the limitations of the linear model parameterisation, we present an extension to the first controller which relies on the true nonlinear dynamics of the system. This approach, even though computationally more intense, ensures that the control model is always valid and allows tracking of full state aggressive trajectories. The last controller addresses the topic of aerial manipulation in which the versatility of
aerial vehicles is combined with the manipulation capabilities of robotic arms. The proposed method relies on the formulation of a hybrid nonlinear MAV-arm
model which also takes into account the effects of contact with the environment. Finally, in order to enable safe operation despite the potential loss of an
actuator, we propose a supervisory algorithm which estimates the health status of each motor. We further showcase how this can be used in conjunction with
the nonlinear controllers described above for fault tolerant MAV flight. While all the developed algorithms are formulated and tested using our specific MAV platforms (consisting of underactuated hexacopters for the free flight experiments, hexacopter-delta arm system for the manipulation experiments),
we further discuss how these can be applied to other underactuated/overactuated MAVs and robotic arm platforms. The same applies to the fault tolerant
control where we discuss different stabilisation techniques depending on the capabilities of the available hardware. Even though the primary focus of this work is on feedback control, we thoroughly describe the custom hardware platforms used for the experimental evaluation, the state estimation algorithms which provide the basis for control
as well as the parameter identification required for the formulation of the various control models.
We showcase all the developed algorithms in experimental scenarios designed to highlight the corresponding strengths and weaknesses as well as show that the proposed methods can run in realtime on commercially available hardware.Open Acces
Survey on Aerial Multirotor Design: a Taxonomy Based on Input Allocation
This paper reviews the impact of multirotor aerial vehicles designs on their abilities in terms of tasks and system properties. We propose a general taxonomy to characterize and describe multirotor aerial vehicles and their design, which we apply exhaustively on the vast literature available. Thanks to the systematic characterization of the designs we exhibit groups of designs having the same abilities in terms of achievable tasks and system properties. In particular, we organize the literature review based on the number of atomic actuation units and we discuss global properties arising from their choice and spatial distribution in the designs. Finally, we provide a discussion on the common traits of the designs found in the literature and the main future open problems
분산된 로터로 구동되는 비행 스켈레톤 시스템의 디자인 상태추정 및 제어
학위논문(박사)--서울대학교 대학원 :공과대학 기계항공공학부,2020. 2. 이동준.In this thesis, we present key theoretical components for realizing flying aerial skeleton system called LASDRA (large-size aerial skeleton with distributed rotor actuation). Aerial skeletons are articulated aerial robots actuated by distributed rotors including both ground connected type and flying type. These systems have recently attracted interest and are being actively researched in several research groups, with the expectation of applying those for aerial manipulation in distant/narrow places, or for the performance with entertaining purpose such as drone shows. Among the aerial skeleton systems, LASDRA system, proposed by our group has some significant advantages over the other skeleton systems that it is capable of free SE(3) motion by omni-directional wrench generation of each link, and also the system can be operated with wide range of configuration because of the 3DOF (degrees of freedom) inter-link rotation enabled by cable connection among the link modules.
To realize this LASDRA system, following three components are crucial: 1) a link module that can produce omni-directional force and torque and enough feasible wrench space; 2) pose and posture estimation algorithm for an articulated system with high degrees of freedom; and 3) a motion generation framework that can provide seemingly natural motion while being able to generate desired motion (e.g., linear and angular velocity) for the entire body. The main contributions of this thesis is theoretically developing these three components, and verifying these through outdoor flight experiment with a real LASDRA system. First of all, a link module for the LASDRA system is designed with proposed constrained optimization problem, maximizing the guaranteed feasible force and torque for any direction while also incorporating some constraints (e.g., avoiding inter-rotor air-flow interference) to directly obtain feasible solution. Also, an issue of ESC-induced (electronic speed control) singularity is first introduced in the literature which is inevitably caused by bi-directional thrust generation with sensorless actuators, and handled with a novel control allocation called selective mapping. Then for the state estimation of the entire LASDRA system, constrained Kalman filter based estimation algorithm is proposed that can provide estimation result satisfying kinematic constraint of the system, also along with a semi-distributed version of the algorithm to endow with system scalability. Lastly, CPG-based motion generation framework is presented that can generate natural biomimetic motion, and by exploiting the inverse CPG model obtained with machine learning method, it becomes possible to generate certain desired motion while still making CPG generated natural motion.본 논문에서는 비행 스켈레톤 시스템 LASDRA (large-size aerial skeleton with distributed rotor actuation) 의 구현을 위해 요구되는 핵심 기법들을 제안하며, 이를 실제 LASDRA 시스템의 실외 비행을 통해 검증한다. 제안된 기법은 1) 전방향으로 힘과 토크를 낼 수 있고 충분한 가용 렌치공간을 가진 링크 모듈, 2) 높은 자유도의 다관절구조 시스템을 위한 위치 및 자세 추정 알고리즘, 3) 자연스러운 움직임을 내는 동시에 전체 시스템이 속도, 각속도 등 원하는 움직임을 내도록 할 수 있는 모션 생성 프레임워크로 구성된다.
본 논문에서는 우선 링크 모듈의 디자인을 위해 전방향으로 보장되는 힘과 토크의 크기를 최대화하는 구속 최적화를 사용하고, 실제 적용가능한 해를 얻기 위해 몇가지 구속조건(로터 간 공기 흐름 간섭의 회피 등)을 고려한다. 또한 센서가 없는 액츄에이터로 양방향 추력을 내는 것에서 야기되는 ESC 유발 특이점 (ESC-induced singularity) 이라는 문제를 처음으로 소개하고, 이를 해결하기 위해 선택적 맵핑 (selective mapping) 이라는 기법을 제시한다. 전체 LASDRA 시스템의 상태추정을 위해 시스템의 기구학적 구속조건을 만족하는 결과를 얻을 수 있도록 구속 칼만 필터 기반의 상태추정 기법을 제시하고, 시스템 확장성을 고려하여 반 분산 (semi-distributed) 개념의 알고리즘을 함께 제시한다. 마지막으로 본 논문에서는 자연스러운 움직임의 생성을 위하여 CPG 기반의 모션 생성 프레임워크를 제안하며, 기계 학습 방법을 통해 CPG 역연산 모델을 얻음으로써 전체 시스템이 원하는 움직임을 낼 수 있도록 한다.1 Introduction 1
1.1 Motivation and Background 1
1.2 Research Problems and Approach 3
1.3 Preview of Contributions 5
2 Omni-Directional Aerial Robot 7
2.1 Introduction 7
2.2 Mechanical Design 12
2.2.1 Design Description 12
2.2.2 Wrench-Maximizing Design Optimization 13
2.3 System Modeling and Control Design 20
2.3.1 System Modeling 20
2.3.2 Pose Trajectory Tracking Control 22
2.3.3 Hybrid Pose/Wrench Control 22
2.3.4 PSPM-Based Teleoperation 24
2.4 Control Allocation with Selective Mapping 27
2.4.1 Infinity-Norm Minimization 27
2.4.2 ESC-Induced Singularity and Selective Mapping 29
2.5 Experiment 38
2.5.1 System Setup 38
2.5.2 Experiment Results 41
2.6 Conclusion 49
3 Pose and Posture Estimation of an Aerial Skeleton System 51
3.1 Introduction 51
3.2 Preliminary 53
3.3 Pose and Posture Estimation 55
3.3.1 Estimation Algorithm via SCKF 55
3.3.2 Semi-Distributed Version of Algorithm 59
3.4 Simulation 62
3.5 Experiment 65
3.5.1 System Setup 65
3.5.2 Experiment of SCKF-Based Estimation Algorithm 66
3.6 Conclusion 69
4 CPG-Based Motion Generation 71
4.1 Introduction 71
4.2 Description of Entire Framework 75
4.2.1 LASDRA System 75
4.2.2 Snake-Like Robot & Pivotboard 77
4.3 CPG Model 79
4.3.1 LASDRA System 79
4.3.2 Snake-Like Robot 80
4.3.3 Pivotboard 83
4.4 Target Pose Calculation with Expected Physics 84
4.5 Inverse Model Learning 86
4.5.1 LASDRA System 86
4.5.2 Snake-Like Robot 89
4.5.3 Pivotboard 90
4.6 CPG Parameter Adaptation 93
4.7 Simulation 94
4.7.1 LASDRA System 94
4.7.2 Snake-Like Robot & Pivotboard 97
4.8 Conclusion 101
5 Outdoor Flight Experiment of the F-LASDRA System 103
5.1 System Setup 103
5.2 Experiment Results 104
6 Conclusion 111
6.1 Summary 111
6.2 Future Works 112Docto
Alocação de controle desacoplada rápida em sistemas de controle superatuados
Over-actuated systems usually require nonlinear control allocation methods to map Virtual Control Actions (VCAs) into Real Control Actions (RCAs). This process requires computational efforts sometimes not available on embedded robotic platforms. It is in this context that this work presents the design of an Quadrotor Tilt-Rotor
(QTR) through a new concept of control allocation with uncoupled RCAs, where the initial nonlinear system is divided into partially dependent linear subsystems with fast and robust convergence. For this purpose, the RCAs are divided into smaller sets, used sequentially to linearize and solve the system. The reduction of the initial nonlinear control effectiveness matrix is improved by selecting each subset in a different arrangement of VCAs. However, the choice of this arrangement may lead to absence, partial or full superposition of VCAs in the subsystems. The technique was validated through mathematical tutorial cases, QTR simulation tests and open field flight and gyroscopic test bench experimental tests. Finally, the control allocation technique proved to be reliable, robust, efficient and applicable in the QTR when there is full superposition of VCAs between the subsystems.Sistemas superatuados geralmente requerem métodos de alocação de controle não lineares para mapear as Ações de Controle Virtuais (ACVs) em Ações de ControleReais (ACRs). Esse processo exige esforços computacionais que, as vezes, são limitados em plataformas robóticas embarcadas. E neste contexto que este trabalho apresenta o projeto de um Veículo Aéreo Não-Tripulado (VANT) do tipo Quadrotor Tilt-Rotor
(QTR) superatuado, utilizando de um novo conceito de alocação de controle com ACRs desacopladas, onde o sistema não-linear inicial é dividido em subsistemas lineares parcialmente dependentes. Para esse propósito, as ACRs são divididas em conjuntos menores, usados sequencialmente para linearizar e resolver o sistema. Para melhorar a redução da matriz de eficácia de controle não-linear inicial, é possível selecionar para
cada subconjunto um arranjo diferente de ACVs. Contudo, a escolha deste arranjo pode gerar ausência, parcial ou completa superposição das ACVs nos subsistemas. A validação da técnica foi realizada através de exemplos matemáticos tutoriais, testes de simulação e experimentais do QTR em uma bancada giroscópica e em campo aberto. Por fim, a técnica de alocação de controle se mostrou confiável, robusta, eficiente e
aplicável no QTR quando se tem superposição completa das ACVs entre os subsistemas
DYNAMICS AND CONTROL OF MINI AERIAL VEHICLE USING MODEL PREDICTIVE CONTROL
Nowadays Mini Aerial Vehicles (MAVs) are popular in many areas such as aerial photography, inspection, surveillance and search and rescue missions in complex and dangerous environments due to their low cost, small size, superior mobility, and hover capability. Multifarious applications of MAVs inspire researchers to concentrate on different types of controllers like linear, nonlinear or learning-based. The attention of this work is to design a robust controller and to develop an accurate mathematical model of Quadrotor, a type of MAV as it behaves roughly in uncertain environments. Quadrotor is an under-actuated and highly nonlinear system with six degrees of freedom (DOF). The mathematical model of quadrotor is derived based on Newton-Euler method that includes aerodynamic drag and moment that are sometimes overlooked in literatures. For higher precision modelling, model uncertainties are also included in the system. In addition, the kinematic model is derived utilizing Euler angles and Quaternion methods. Quaternion approach has the advantage of singularity free orientation while Euler angles are easy to visualize. This work investigates the performance of three different controllers which includes Proportional-Integral-Derivative (PID), Linear Quadratic Regulator (LQR) and Model Predictive Control (MPC) based on several performance evaluation factors. PID offers fast response to the system comparing to other controllers although choosing proper gain is challenging for PID. However, it cannot handle directly under-actuated system and due to the fact, some states are required to be decoupled. LQR ensures fast response and can deal with Multiple Input Multiple Output (MIMO) system at the same time. The main drawback of the LQR controller is its incapability of dealing with steady-state error. Conversely, MPC has the functionalities of dealing with MIMO system with constraints and uncertainties while other controllers fail. The performance of the controllers are presented based on tracking accuracy using Root Mean Square Error (RMSE) method and control stability using control input norm method. MATLAB and Simulink environment is considered to carry out the simulations. Based on simulated experiments, it is found that MPC could track the trajectories more accurately with stable control effort comparing to PID controllers and LQR
Contributions to shared control and coordination of single and multiple robots
L’ensemble des travaux présentés dans cette habilitation traite de l'interface entre un d'un opérateur humain avec un ou plusieurs robots semi-autonomes aussi connu comme le problème du « contrôle partagé ».Le premier chapitre traite de la possibilité de fournir des repères visuels / vestibulaires à un opérateur humain pour la commande à distance de robots mobiles.Le second chapitre aborde le problème, plus classique, de la mise à disposition à l’opérateur d’indices visuels ou de retour haptique pour la commande d’un ou plusieurs robots mobiles (en particulier pour les drones quadri-rotors).Le troisième chapitre se concentre sur certains des défis algorithmiques rencontrés lors de l'élaboration de techniques de coordination multi-robots.Le quatrième chapitre introduit une nouvelle conception mécanique pour un drone quadrirotor sur-actionné avec pour objectif de pouvoir, à terme, avoir 6 degrés de liberté sur une plateforme quadrirotor classique (mais sous-actionné).Enfin, le cinquième chapitre présente une cadre général pour la vision active permettant, en optimisant les mouvements de la caméra, l’optimisation en ligne des performances (en terme de vitesse de convergence et de précision finale) de processus d’estimation « basés vision »
飛行ロボットにおける人間・ロボットインタラクションの実現に向けて : ユーザー同伴モデルとセンシングインターフェース
学位の種別: 課程博士審査委員会委員 : (主査)東京大学准教授 矢入 健久, 東京大学教授 堀 浩一, 東京大学教授 岩崎 晃, 東京大学教授 土屋 武司, 東京理科大学教授 溝口 博University of Tokyo(東京大学