Development of Autonomous Underwater Vehicles (AUVs) has permitted the automatization of many tasks originally achieved with manned vehicles in underwater environments. Teams of AUVs designed to work within a common mission are opening the possibilities for new and more complex applications. In underwater environments, communication, localization, and navigation of AUVs are considered challenges due to the impossibility of relying on radio communications and global positioning systems. For a long time, acoustic systems have been the main approach for solving these challenges. However, they present their own shortcomings, which are more relevant for AUV teams. As a result, researchers have explored different alternatives. To summarize and analyze these alternatives, a review of the literature is presented in this paper. Finally, a summary of collaborative AUV teams and missions is also included, with the aim of analyzing their applicability, advantages, and limitations.

Autonomous Underwater Vehicles: Localization, Navigation, and Communication for Collaborative Missions

Locating AED Enabled Medical Drones to Enhance Cardiac Arrest Response Times

Load transportation by quadrotors and similar aircrafts is a topic of great interest to the robotics community nowadays, most likely due to logistic gains for deliveries of commercial cargo. Aiming at being the first reading for novice researchers and graduate students, this survey highlights meaningful research works of several groups worldwide, considering two basic approaches, namely grasped and cable-suspended load transportation. Different control techniques and maneuver strategies are analyzed, and their benefits and drawbacks are discussed. Moreover, experimental validation was a key aspect to the highlighted works, thus, links to the videos showing the experimental results are provided for each work.

A Survey on Load Transportation Using Multirotor UAVs

An unmanned quadrotor presents excellent mobility to fly freely in complex environments, which makes it an ideal choice for aerial transferring tasks. During the transferring process, it is very challenging to eliminate the swing, since there is no direct control on the payload. The quadrotor transportation system presents the great challenge of the cascaded underactuated–underactuated property, which makes it extremely difficult to simultaneously implement accurate quadrotor positioning and efficient payload swing suppression. In this paper, a nonlinear hierarchical control scheme is proposed for a quadrotor transportation system, which takes full advantage of the cascade property of the system and separates the controller design for the inner loop and the outer loop, respectively, to facilitate the design procedure. More specifically, for the outer loop subsystem, based on the proposed energy storage function, a virtual control vector is designed, which introduces a saturation function to make the desired attitude free of any singularities. For the inner loop, a coordinate-free geometric attitude tracking controller is designed on the Lie group to drive the quadrotor to its desired attitude. It is shown theoretically by Lyapunov techniques and LaSalle's invariance theorem that the equilibrium point of the overall system is asymptotically stable. As illustrated by experimental results, the proposed control law presents advantages such as high control precision, effective payload swing suppression, and so on.

Nonlinear Hierarchical Control for Unmanned Quadrotor Transportation Systems

Reference EPFL-CONF-232508 URL: http://rpg.ifi.uzh.ch/docs/RSS17_Foehn.pdf Record created on 2017-11-21, modified on 2017-11-21

http://www.roboticsproceedings.org/rss13/p30.pdf

Fast Trajectory Optimization for Agile Quadrotor Maneuvers with a Cable-Suspended Payload

In the present work a mathematical model and a control methodology for a special class of underactuated mechanical system, composed by an Unmanned Aerial Vehicle (UAV) kind quadrotor transporting a cable-suspended payload, is proposed. The Euler-Lagrange formulation is used to derive the dynamic model of the system, where the integrated dynamics of the quadrotor, cable and payload are considered. An Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) for a quadrotor UAV transporting a cable-suspended payload is developed. The control law designed does not depend on the swing angle of the cable. The control objective is to transport the payload from point to point, with swing suppression along trajectory. Experimental results are shown to evaluate the proposed control law.

Passivity based control for a quadrotor UAV transporting a cable-suspended payload with minimum swing

Design and implementation of a fully-working multirotor Unmanned Aerial-Underwater Vehicle (UAUV) was successfully accomplished in the present work. The proposed prototype consists of a multirotor vehicle in an octo-quadcopter configuration, which is well suited for good transition between mediums. The mathematical model is provided by means of the Newton-Euler formalism, highlighting the impact of the drastic change in density on the vehicle dynamics. A hierarchical controller is employed for attitude tracking, utilizing a proportional control law in cascade with a body angular rate Proportional-Integral-Derivative (PID) controller. Altitude stabilization is achieved by a PID controller with compensation of the restoring forces, while a gain scheduling strategy handles the change of medium. Furthermore, the proposed platform was extensively tested in simulations and real-time experiments under real conditions, with promising results in both mediums, and seamless transition between them.

Design and implementation of multirotor aerial-underwater vehicles with experimental results

This letter studies the problem of autonomous navigation for unmanned underwater vehicles, using computer vision for localization. Parallel tracking and mapping is employed to localize the vehicle with respect to a visual map, using a single camera, whereas an extended Kalman filter (EKF) is used to fuse the visual information with data from an inertial measurement unit, in order to recover the scale of the map and improve the pose estimation. A proportional integral derivative controller controller with compensation of the restoring forces is proposed to accomplish trajectory tracking, where a pressure sensor and a magnetometer provide feedback for depth control and yaw, respectively, while the remaining states are provided by the EKF. Real-time experiments are presented to validate the navigation strategy, using a commercial remotely operated vehicle (ROV), the BlueROV2, which was adapted to perform as an autonomous underwater vehicle with the help of the robot operative system.

Autonomous Navigation for Unmanned Underwater Vehicles: Real-Time Experiments Using Computer Vision

This paper presents results on the modeling and control for an Unmanned Aerial Vehicle (UAV) kind quadrotor transporting a cable-suspended payload. The mathematical model is based on Euler-Lagrange formulation, where the integrated dynamics of the quadrotor, cable and payload are considered. An Interconnection and Damping Assignment Passivity - Based Control (IDA-PBC) for a quadrotor UAV transporting a cable-suspended payload is designed. The control objective is to transport the payload from point to point transfer with swing suppression along trajectory. The cable is considered rigid. Numerical simulations are carried out to validate the overall control approach.

IDA-PBC methodology for a quadrotor UAV transporting a cable-suspended payload

This paper presents a simple and easy to implement sensor data fusion algorithm, using a Kalman filter (KF) in a loosely coupled scheme, for estimation of the velocity and position of an object evolving in a three dimensional space. A global positioning system (GPS) provides the position measurement while the velocity measurement is taken from the optical flow sensor, finally, the inertial navigation system (INS) gives the acceleration, which is considered as the input of the system. Real time experimental results are shown to validate the proposed algorithm.

/pdf/gps-ins-optic-flow-data-fusion-for-position-and-velocity-1cyhyrxuhd.pdf

D. A. Mercado

Papers

Passivity based control for a quadrotor UAV transporting a cable-suspended payload with minimum swing

Design and implementation of multirotor aerial-underwater vehicles with experimental results

Autonomous Navigation for Unmanned Underwater Vehicles: Real-Time Experiments Using Computer Vision

IDA-PBC methodology for a quadrotor UAV transporting a cable-suspended payload

GPS/INS/optic flow data fusion for position and Velocity estimation