Passive Compliance Control of Aerial Manipulators

This paper presents a passive compliance control for aerial manipulators to achieve stable environmental interactions. The main challenge is the absence of actuation along body-planar directions of the aerial vehicle which might be required during the interaction to preserve passivity. The controller proposed in this paper guarantees passivity of the manipulator through a proper choice of end-effector coordinates, and that of vehicle fuselage is guaranteed by exploiting time domain passivity technique. Simulation studies validate the proposed approach.Comment: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 201

Design, Modeling, and Geometric Control on SE(3) of a Fully-Actuated Hexarotor for Aerial Interaction

In this work we present the optimization-based design and control of a fully-actuated omnidirectional hexarotor. The tilt angles of the propellers are designed by maximizing the control wrench applied by the propellers. This maximizes (a) the agility of the UAV, (b) the maximum payload the UAV can hover with at any orientation, and (c) the interaction wrench that the UAV can apply to the environment in physical contact. It is shown that only axial tilting of the propellers with respect to the UAV's body yields optimal results. Unlike the conventional hexarotor, the proposed hexarotor can generate at least 1.9 times the maximum thrust of one rotor in any direction, in addition to the higher control torque around the vehicle's upward axis. A geometric controller on SE(3) is proposed for the trajectory tracking problem for the class of fully actuated UAVs. The proposed controller avoids singularities and complexities that arise when using local parametrizations, in addition to being invariant to a change of inertial coordinate frame. The performance of the controller is validated in simulation.Comment: 9 pages, 9 figures, ICRA201

Design and Control of Omni-directional aerial robot

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2016. 2. 이동준.우리는 비대칭적인 분산된 멀티 로터 배치로 SE(3)에서 fully-actuated한 특성을 가지고 비행과 회전이 동시에 가능하여 일반적인 비행로봇이 가지고 있는 under-actuation한 문제를 극복 할 수 있는 전방향 비행 로봇이라는 새로운 디자인의 비행 로봇을 제안한다. 먼저 우리는 각 로터들 사이의 공기역학적인 간섭을 최소화함과 동시에 최대의 제어 렌치를 생수 할 수 있게 하기 위해 로터 배치의 최적화 작업을 수행한다. 우리는 SE(3)에서 ODAR 시스템의 동역학 모델링을 제시하고 병진운동과 회전운동의 제어 디자인을 진행한다. 우리는 또한 ODAR 시스템을 실제 제작하고 그것의 성능을 검증한다. 기존의 비행로봇과는 완전히 다른 시스템으로서 우리는 ODAR 시스템이 전방향 렌치 생성이 중요한 항공 매니퓰레이터나 가상현실 렌더링 3D 환경구축을 위한 전방향 구동에서의 촬영 성능을 지닐 수 있는 항공 촬영 역할을 수행 할 것으로 믿는다.We propose a novel aerial robot system, Omni-Directional Aerial Robot (ODAR), which is fully-actuated in SE(3) with asymmetrically distributed multiple rotors and can fly and rotate at the same time, thereby, overcoming the well-known under-actuation problem of conventional multi-rotor aerial robots (or simply drones). We first perform optimization of rotor distribution to maximize control wrench generation in SE(3) while minimizing aero-dynamic interference among the rotors. We present dynamics modeling of the ODAR system in SE(3) and simultaneous translation / orientation control design. We also implement a ODAR system and experimentally validate its performance. Being completely different from the conventional drone, we believe this ODAR system would be promising for such applications as aerial manipulation, where omni-directional wrench generation is important, and also as aerial photography, where an ability to taking photos in omni-direction is desired for 3D environment reconstruction for VR scene rendering.1 서론 1 1.1 연구 동기 및 목적 1 1.2 연구 성과 4 2 시스템 디자인 및 제어 설계 6 2.1 시스템 디자인 6 2.2 제어 설계 16 3 시뮬레이션 21 3.1 시뮬레이션 준비 21 3.2 시뮬레이션 결과 24 4 시스템 제작 27 4.1 시스템 제작 준비 27 4.2 시스템 제작 구성품 28 4.3 시스템 제작 통합 34 5 실험 36 5.1 실험 준비 36 5.2 실험 결과 38 5.2.1 원형 궤적 추적 39 5.2.2 3D 영상촬영 모션 42 5.2.3 수직 구동 작업 45 6 결론 49 6.1 결론 49 6.2 향후 과제 50 참고문헌 52 Abstract 57Maste

6D Pose Task Trajectory Tracking for a Class of 3D Aerial Manipulator From Differential Flatness

In this paper, the dynamics and control of a novel class of aerial manipulator for the purpose of end effector full pose trajectory tracking are investigated. The 6D pose of the end effector is set as a part of the flat output, from which the conditions that the system has the proposed flat output is obtained. The control law for the end effector tracking purpose is designed. The core part of the controller is an almost global controller in the configuration space of the system. From the transformation between the state space and the output space, the tracking control of the end effector in SE (3) is also achieved. The stability of the controlled system is analyzed. A numerical example is presented to demonstrate the theoretical analysis

결합된 쿼드로터 무인비행로봇의 모델링 및 제어

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2015. 2. 이동준.본 논문에서는 두 대의 쿼드로터 무인비행로봇을 비스듬히 결합한 새로운 시스템을 제시한다. 본 시스템은 기존의 한 대의 쿼드로터가 가지는 부족구동(underactuation)적인 측면과 낮은 적재하중의 문제를 극복하는 장점을 가진다. 즉, 기존에 쿼드로터가 4개의 구동 자유도를 갖는데 반해 본 시스템은 5개의 구동 자유도를 가져 한 차원의 제어가 추가로 가능하며, 이는 두 쿼드로터가 결합된 축 방향으로의 피치 (pitch) 동작에 대한 자유도로 활용할 수 있다. 이러한 특성은 공중 도구조작 (aerial tool operation) 등과 같은 실제 임무를 수행할 때 매우 유용하게 적용 가능하다. 제시된 비스듬히 결합한 쿼드로터 무인비행로봇 시스템에 대해 동역학 및 추력 관계식을 모델링하고, 궤적 추적 (trajectory tracking) 을 위해 백스텝핑 제어기법을 활용한 제어를 설계하였다. 또한, 각 로터에서의 추력들이 항상 양의 값을 가져야하는 제약조건을 만족시키기 위한 최적화 기법 을 제시하였다. 다양한 시뮬레이션을 통해 본 시스템과 제어기를 검증하였고 그 결과를 제시하였다.In this thesis, we introduce a novel concept of asymmetrically coupled quadrotor UAVs (Unmanned Aerial Vehicles) system. The proposed system is composed with two quadrotor UAVs that are asymmetrically coupled with each other. This coupled system has advantages in the sense of overcoming under-actuation and payload problems compared to single conventional quadrotor UAV. That is, the proposed system has 5 actuation DOFs while single quadrotor UAV has 4 actuation DOFs, where the additional actuation can be exploited for decoupling translation and rotation in a certain direction. This feature increases the versatility and is useful for real tasks such as aerial tool operation. We first model the coupled quadrotor system and design a controller which is based on the backstepping control and optimization to guarantee positiveness of thrusts. Simulation results are presented to validate the theory and to demonstrate the advantages of the proposed system.1 Introduction 1 1.1 Motivation and Objectives 1 1.2 State of the Art 3 1.3 Contribution of this Work 4 2 System Modeling 6 2.1 Asymmetrically Coupled Quadrotor UAVs 6 2.2 Dynamics of Asymmetrically Coupled Quadrotor UAVs 9 2.3 Thrust Relationship 13 3 Control Design 16 3.1 Backstepping Control 17 3.2 Positive Thrust Constraint 23 4 Simulation 26 4.1 Simulation Scheme 26 4.2 Simulation Results 28 4.2.1 Trajectory tracking 29 4.2.2 Translation along x-axis without rotation 31 4.2.3 Rotation without translation 35 4.2.4 Combination case 37 4.2.5 Tool operation example 40 5 Conclusion and Future Work 44 5.1 Conclusion 44 5.2 Future Work 45Maste

A review of aerial manipulation of small-scale rotorcraft unmanned robotic systems

Small-scale rotorcraft unmanned robotic systems (SRURSs) are a kind of unmanned rotorcraft with manipulating devices. This review aims to provide an overview on aerial manipulation of SRURSs nowadays and promote relative research in the future. In the past decade, aerial manipulation of SRURSs has attracted the interest of researchers globally. This paper provides a literature review of the last 10 years (2008–2017) on SRURSs, and details achievements and challenges. Firstly, the definition, current state, development, classification, and challenges of SRURSs are introduced. Then, related papers are organized into two topical categories: mechanical structure design, and modeling and control. Following this, research groups involved in SRURS research and their major achievements are summarized and classified in the form of tables. The research groups are introduced in detail from seven parts. Finally, trends and challenges are compiled and presented to serve as a resource for researchers interested in aerial manipulation of SRURSs. The problem, trends, and challenges are described from three aspects. Conclusions of the paper are presented, and the future of SRURSs is discussed to enable further research interests

Autonomous aerial robot for high-speed search and intercept applications

In recent years, high-speed navigation and environment interaction in the context of aerial robotics has become a field of interest for several academic and industrial research studies. In particular, Search and Intercept (SaI) applications for aerial robots pose a compelling research area due to their potential usability in several environments. Nevertheless, SaI tasks involve a challenging development regarding sensory weight, onboard computation resources, actuation design, and algorithms for perception and control, among others. In this work, a fully autonomous aerial robot for high-speed object grasping has been proposed. As an additional subtask, our system is able to autonomously pierce balloons located in poles close to the surface. Our first contribution is the design of the aerial robot at an actuation and sensory level consisting of a novel gripper design with additional sensors enabling the robot to grasp objects at high speeds. The second contribution is a complete software framework consisting of perception, state estimation, motion planning, motion control, and mission control in order to rapidly and robustly perform the autonomous grasping mission. Our approach has been validated in a challenging international competition and has shown outstanding results, being able to autonomously search, follow, and grasp a moving object at 6 m/s in an outdoor environment.Agencia Estatal de InvestigaciónKhalifa Universit

Design and control of next-generation uavs for effectively interacting with environments

In this dissertation, the design and control of a novel multirotor for aerial manipulation is studied, with the aim of endowing the aerial vehicle with more degrees of freedom of motion and stability when interacting with the environments. Firstly, it presents an energy-efficient adaptive robust tracking control method for a class of fully actuated, thrust vectoring unmanned aerial vehicles (UAVs) with parametric uncertainties including unknown moment of inertia, mass and center of mass, which would occur in aerial maneuvering and manipulation. The effectiveness of this method is demonstrated through simulation. Secondly, a humanoid robot arm is adopted to serve as a 6-degree-of-freedom (DOF) automated flight testing platform for emulating the free flight environment of UAVs while ensuring safety. Another novel multirotor in a tilt-rotor architecture is studied and tested for coping with parametric uncertainties in aerial maneuvering and manipulation. Two pairs of rotors are mounted on two independently-controlled tilting arms placed at two sides of the vehicle in a H configuration to enhance its maneuverability and stability through an adaptive robust control method. In addition, an impedance control algorithm is deployed in the out loop that modifies the trajectory to achieve a compliant behavior in the end-effector space for aerial drilling and screwing tasks