This paper addresses the problem of cooperative transport of a point mass hoisted by two aerial robots. Treating the robots as a leader and a follower, the follower stabilizes the system with respect to the leader using only feedback from its Inertial Measurement Units (IMU). This is accomplished by neglecting the acceleration of the leader, analyzing the system through the generalized coordinates or the cables' angles, and employing an observation model based on the IMU measurements. A lightweight estimator based on an Extended Kalman Filter (EKF) and a controller are derived to stabilize the robot-payload-robot system. The proposed methods are verified with extensive flight experiments, first with a single robot and then with two robots. The results show that the follower is capable of realizing the desired quasi-static trajectory using only its IMU measurements. The outcomes demonstrate promising progress towards the goal of autonomous cooperative transport of a suspended payload via small flying robots with minimal sensing and computational requirements.
This paper presents an estimation and control algorithm for an aerial manipulator using a hexacopter with a 2-DOF robotic arm. The unknown parameters of a payload are estimated by an on-line estimator based on parametrization of the aerial manipulator dynamics. With the estimated mass information and the augmented passivity-based controller, the aerial manipulator can fly with the unknown object. Simulation for an aerial manipulator is performed to compare estimation performance between the proposed control algorithm and conventional adaptive sliding mode controller. Experimental results show …
PolyFly: Polytopic Optimal Planning for Collision-Free Cable-Suspended Aerial Payload Transportation
University of California Berkeley, Department of Electrical Engineering and Computer Sciences（加州大学伯克利分校电子工程与计算机科学系）；Worcester Polytechnic Institute, Robotics Engineering（沃思黑德技术学院机器人工程）
German Aerospace Center (DLR)（德国航空航天中心（DLR））；Skolkovo Institute of Science and Technology (Skoltech)（斯科尔科沃科学技术研究所（斯科尔科沃理工学院））；LAAS-CNRS（法国国家科学研究中心自动化系统实验室）；Université de Toulouse（图卢兹大学）；CNRS（法国国家科学研究中心）
High risk of a collision between rotor blades and the obstacles in a complex environment imposes restrictions on the aerial manipulators. To solve this issue, a novel system cable-Suspended Aerial Manipulator (SAM) is presented in this paper. Instead of attaching a robotic manipulator directly to an aerial carrier, it is mounted on an active platform which is suspended on the carrier by means of a cable. As a result, higher safety can be achieved because the aerial carrier can keep a distance from the obstacles. For self-stabilization, the SAM is equipped with two actuation systems: winches an…
This paper studies the problem of fast and safe aerial payload transport by a single quadcopter in urban areas. The quadcopter payload system (QPS) is considered as a rigid body and modeled with a nonlinear dynamics. The urban area is modeled as an obstacle-laden environment with obstacle geometries obtained by incorporating realistic LIDAR data. Our approach for payload transport is decomposed into high-level motion planning and low-level trajectory control. For the low-level trajectory tracking, a feedback linearization control is applied to stably track the desired trajectory of the quadcop…
University of California, Berkeley（加州大学伯克利分校）；Facebook AI Research（脸书人工智能研究院）
Transporting suspended payloads is challenging for autonomous aerial vehicles because the payload can cause significant and unpredictable changes to the robot's dynamics. These changes can lead to suboptimal flight performance or even catastrophic failure. Although adaptive control and learning-based methods can in principle adapt to changes in these hybrid robot-payload systems, rapid mid-flight adaptation to payloads that have a priori unknown physical properties remains an open problem. We propose a meta-learning approach that "learns how to learn" models of altered dynamics within seconds …
A quadcopter is an under-actuated system with only four control inputs for six degrees of freedom, and yet the human control of a quadcopter is simple enough to be learned with some practice. In this work, we consider the problem of human control of a multiple quadcopters system to transport a cable-suspended payload. The coupled dynamics of the system, due to the inherent physical constraints, is used to develop a leader-follower architecture where the leader quadcopter is controlled directly by a human operator and the followers are controlled with the proposed Payload Attitude Controller an…
German Aerospace Center (DLR)（德国航空航天中心）；Skolkovo Institute of Science and Technology (Skoltech)（斯科尔科沃科学技术研究所）
This paper presents a design of oscillation damping control for the cable-Suspended Aerial Manipulator (SAM). The SAM is modeled as a double pendulum, and it can generate a body wrench as a control action. The main challenge is the fact that there is only one onboard IMU sensor which does not provide full information on the system state. To overcome this difficulty, we design a controller motivated by a simplified SAM model. The proposed controller is very simple yet robust to model uncertainties. Moreover, we propose a gain tuning rule by formulating the proposed controller in the form of out…
Observer-based Controller Design for Oscillation Damping of a Novel Suspended Underactuated Aerial Platform
Automation and Control Institute (ACIN), TU Wien（维也纳技术大学自动化与控制研究所（ACIN））；Austrian Institute of Technology (AIT) GmbH（奥地利技术研究院（AIT）有限公司）；Institute of Robotics and Mechatronics, German Aerospace Center (DLR)（德国航空航天中心机器人与机电一体化研究所（DLR））
Aerial robotic systems have raised emerging interests in recent years. In this article, we propose a novel aerial manipulator system that is significantly different from conventional aerial discrete manipulators: An Aerial Continuum Manipulator (AeCoM). The AeCoM compactly integrates a quadrotor with a tendon-driven continuum robotic manipulator. Due to the compact design and the payload bearing ability of tendon-driven continuum robotic arms, the proposed system solved the conflict between payload capacity and dexterity lying in conventional aerial manipulators. Two contributions are made in …
Learning Swing-up Maneuvers for a Suspended Aerial Manipulation Platform in a Hierarchical Control Framework
Automation and Control Institute (ACIN), TU Wien（自动化与控制研究所（ACIN）、维也纳技术大学）；Austrian Institute of Technology (AIT) GmbH（奥地利技术研究所（AIT） GmbH）；Institute of Robotics and Mechatronics, German Aerospace Center (DLR)（机器人与机电研究所、德国航天中心（DLR））
Hierarchical Whole-body Control of the cable-Suspended Aerial Manipulator endowed with Winch-based Actuation
German Aerospace Center (DLR)（德国航空航天中心（DLR））；University of Twente（特文特大学）；Dextrous Robotics Inc.（灵巧机器人公司）；Instituto Tecnológico de Aeronáutica（航空技术研究所）；Korea Advanced Institute of Science and Technology (KAIST)（韩国科学技术院（KAIST））；TU Wien（维也纳工业大学）
California Institute of Technology（加州理工学院）；ETH Zurich（苏黎世联邦理工学院）；Northeastern University（东北大学）
The feasibility of performing airborne and ground manipulation, perception, and reconnaissance using wheeled rovers, unmanned aerial vehicles, CubeSats, SmallSats and more have been evaluated before. Among all of these solutions, balloon-based systems possess merits that make them extremely attractive, e.g., a simple operation mechanism and endured operation time. However, there are many hurdles to overcome to achieve robust loitering performance in balloon-based applications. We attempt to identify design and control challenges, and propose a novel robotic platform that allows for the applica…
Hook-Based Aerial Payload Grasping from a Moving Platform
Systems and Control Lab, HUN-REN Institute for Computer Science and Control（系统与控制实验室，HUN-REN计算机科学与控制研究所）；National Laboratory for Autonomous Systems（自主系统国家实验室）；Control Systems Group of the Eindhoven University of Technology（埃因霍温理工大学控制系统组）
Cooperative Control of Multi-Quadrotors for Transporting Cable-Suspended Payloads: Obstacle-Aware Planning and Event-Based Nonlinear Model Predictive Control
Toronto Metropolitan University（多伦多都会大学）；University of Alberta（阿尔伯塔大学）
New York University（纽约大学）；New York University Abu Dhabi（纽约大学阿布扎比分校）
The control problem of a multi-copter swarm, mechanically coupled through a modular lattice structure of connecting rods, is considered in this article. The system's structural elasticity is considered in deriving the system's dynamics. The devised controller is robust against the induced flexibilities, while an inherent adaptation scheme allows for the control of asymmetrical configurations and the transportation of unknown payloads. Certain optimization metrics are introduced for solving the individual agent thrust allocation problem while achieving maximum system flight time, resulting in a…
Southern University of Denmark（丹麦南方大学）；Delft University of Technology（代尔夫特理工大学）
We propose a combined method for the collaborative transportation of a suspended payload by a team of rotorcraft. A recent distance-based formation-motion control algorithm based on assigning distance disagreements among robots generates the acceleration signals to be tracked by the vehicles. In particular, the proposed method does not need global positions nor tracking prescribed trajectories for the motion of the members of the team. The acceleration signals are followed accurately by an Incremental Nonlinear Dynamic Inversion controller designed for rotorcraft that measures and resists the …
Payload trajectory tracking control for aerial transportation systems with cable length online optimization
Institute of Robotics and Automatic Information System, College of Artificial Intelligence（机器人与自动化信息系统研究所，人工智能学院）；Tianjin Key Laboratory of Intelligent Robotics, Nankai University（天津智能机器人重点实验室，南开大学）；Institute of Intelligence Technology and Robotic Systems（智能技术与机器人系统研究所）；Shenzhen Research Institute of Nankai University（南开大学深圳研究院）
Self-Organizing Aerial Swarm Robotics for Resilient Load Transportation : A Table-Mechanics-Inspired Approach
School of Automation Science and Electrical Engineering, Beihang University（北京航空航天大学自动化科学与电气工程学院）；Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong（香港中文大学机械与自动化工程系）
A Cooperative Aerial System of A Payload Drone Equipped with Dexterous Rappelling End Droid for Cluttered Space Pickup
School of Aerospace Science and Engineering, Beihang University（北京航空航天大学航空航天科学与工程学院）；Hangzhou International Innovation Institute of Beihang University（北京航空航天大学杭州国际创新研究院）；Institute of Unmanned System, Beihang University（北京航空航天大学无人系统研究院）；Tianmushan Laboratory（天门山实验室）
This paper is concerned with learning transferable contact models for aerial manipulation tasks. We investigate a contact-based approach for enabling unmanned aerial vehicles with cable-suspended passive grippers to compute the attach points on novel payloads for aerial transportation. This is the first time that the problem of autonomously generating contact points for such tasks has been investigated. Our approach builds on the underpinning idea that we can learn a probability density of contacts over objects' surfaces from a single demonstration. We enhance this formulation for encoding aer…
Learn Structure, Adapt on the Fly: Multi-Scale Residual Learning and Online Adaptation for Aerial Manipulators
Robotics Research Center, IIIT Hyderabad, India（IIIT Hyderabad机器人研究中心，印度）；Department of Computer Science, University of Manchester, UK（曼彻斯特大学计算机科学系，英国）；Newcastle University, UK（新castle大学，英国）
Autonomous Aerial Manipulation via Contextual Contrastive Meta Reinforcement Learning
National Key Laboratory of Novel Software Technology, Nanjing University（南京大学计算机软件新技术国家重点实验室）；School of Artificial Intelligence, Nanjing University（南京大学人工智能学院）；Faculty of Robot Science and Engineering, Northeastern University（东北大学机器人科学与工程学院）；National Key Lab of Autonomous Intelligent Unmanned Systems, Beijing Institute of Technology（北京理工大学自主智能无人系统国家重点实验室）
École Centrale de Nantes (ECN)（南特中央理工学院）；Laboratoire des Sciences du Numérique de Nantes (LS2N)（南特数字科学实验室）；Centre National de la Recherche Scientifique (CNRS)（法国国家科学研究中心）
Aerial Cable Towed Systems (ACTS) are composed of several Unmanned Aerial Vehicles (UAVs) connected to a payload by cables. Compared to towing objects from individual aerial vehicles, an ACTS has significant advantages such as heavier payload capacity, modularity, and full control of the payload pose. They are however generally large with limited ability to meet geometric constraints while avoiding collisions between UAVs. This paper presents the modelling, performance analysis, design, and a proposed controller for a novel ACTS with variable cable lengths, named Variable Aerial Cable Towed Sy…
Nonlinear Predictive Control of the Continuum and Hybrid Dynamics of a Suspended Deformable Cable for Aerial Pick and Place
Department of Computer, Control and Management Engineering, Sapienza University of Rome（计算机、控制与管理工程系，罗马萨皮恩扎大学）；Robotics and Mechatronics Department, Electrical Engineering, Mathematics, and Computer Science (EEMCS) Faculty, University of Twente（机器人与机电系，电气工程、数学与计算机科学（EEMCS） faculty，特文特大学）
