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This paper describes the tracking guidance for the autonomous UAV landing and the vision-based detection of the marker on the moving vehicle with the real-time image processing system. The detection of the marker is based on the color detection algorithm with morphological filter and the tracking guidance is based on the relative distance between the UAV and the vehicle. In order to track and land...
We present a two step path planning algorithm for unmanned aerial vehicles (UAVs) with kinematic constraints in the presence of polygonal obstacles. We use a visibility graph representation for the environment and a Dubins vehicle approximation to model UAV kinematics. A modified Dijkstra's shortest path algorithm is developed as first step of our approach to plan paths for a UAV. The algorithm in...
Micro aerial vehicles, such as multirotors, are particularly well suited for autonomous monitoring, inspection, and surveillance, e.g., for doing inventory in large warehouses. Key prerequisites for efficient MAV inventory missions is time- and energy-efficient flight. Generated trajectories must assure the visiting of certain waypoints while preventing large deviations or overshoot, as these can...
This paper describes a control approach for transitioning VTOL UAVs controlled by differential thrust, allowing to fly in all flight phases spanning a continuous transition between hover and cruise flight. A quaternion based attitude controller makes use of an additional reference frame that is rotated by the transition angle with respect to the body-fixed frame. This approach allows intuitive control...
There is strong interest in Micro Aerial Vehicle (MAV) control architectures which are able to systematically respect physical limitations of the plant. Nonlinear Model Predictive Control (NMPC) inherits the required constraint handling abilities and is easy to reconfigure in case of plant degradation. This work presents a promising cascaded control architecture for multirotors for the task to follow...
This paper presents the design and simulation of an energy-based control strategy to stabilize a quadrotor described with unit quaternions and their axis-angle representation. The mathematical model is based on Euler-Lagrange formulation using a logarithmic mapping in the quaternion space. The proposed solution introduces a new approach: a quaternion-energy-based control, which introduces an energy...
This work presents the modeling and control of an aerial manipulator based on a quadrotor with a robotic arm using the dual quaternion approach. First the kinematic model of the complete system is obtained using dual quaternions to represent multiple rotations and translations, then the dynamic model is developed via the Newton-Euler formalism. A position control law is used to stabilize the vehicle...
This work focuses on the remote sensing of thermal updrafts under cumulus clouds for glider UAVs. Previous remote estimation techniques assume unlimited thermal lifespans under the clouds. Naturally occuring thermals are however of limited duration which increases the risk of an outlanding when utilizing these methods. By observing the evolution of the cloud's diameter, human glider pilots draw conclusions...
Long-time planning horizons are required to safely navigate one vehicle in the presence of another, possibly non-cooperative vehicle. They give rise to computational issues preventing the real-time implementation of safe navigation algorithms. In this paper, we consider two nonholonomic vehicles, of which one (blue) has the goal to enter the “tail” of the other (red). Neither the goal nor the navigation...
This paper presents a novel obstacle avoidance scheme for UAVs. This scheme is based on the use of a technique recently developed by one of the authors, which is based on a transformation of a variable constraint into an input saturation. In the case of obstacle avoidance, this saturation is designed so as to ensure a safe trajectory around the obstacles, offering a proof of this desired behavior...
In this paper, we present two novel guidance laws for an unmanned aerial vehicle (UAV) equipped with a fixed camera to track a mobile ground target. The system dynamics is established in the level local coordinate frame, removing the need of converting the target location information to the global inertial frame. The first guidance law is developed using backstepping technique requiring the estimation...
Two missile guidance laws viz. Pursuit Guidance (PG) and Trajectory Shaping (TS), have been adopted to aggressively follow curved, compact trajectories using a quadrotor. The concept of virtual target navigation has been utilized to generate the required curved trajectories. Simulations and flight tests have been performed using a quadrotor and the performance characteristics obtained have been compared...
This paper presents a framework that integrates vector field based motion planning techniques with an optimal path planner. The main motivation for this integration is the solution of UAVs' motion planning problems that are easily and intuitively solved using vector fields, but are very difficult to be even posed as optimal motion planning problems, mainly due to the lack of clear cost functions....
Several approaches can be identified in the literature for area decomposition: Grid based methods, Cellular decomposition and Boustrophedon (or Morse) decomposition. This paper proposes a novel discretization method for the area based on computational geometry approaches. By using a Constrained Delaunay Triangulation, a complex area is segmented in cells which have the size of the projected field...
This paper concerns a distributed control approach of a fleet of Unmanned Aerial Vehicles (UAVs) based on a Leaderless strategy. The independent distributed particle swarm Optimization algorithms are used to develop this approach. The goal is to get a set of UAVs to fly on a 2D plane while converging to a predefined spatial configuration around a rendezvous point. The developed method would be applied...
Within this paper, the problem of 3D inspection path planning for distributed infrastructure using aerial robots that are subject to time constraints is addressed. The proposed algorithm handles varying spatial properties of the infrastructure facilities, accounts for their different importance and exploration function and computes an overall inspection path of high inspection reward while respecting...
A planar path planner for a persistent surveillance application in the presence of static obstacles is developed for a team of homogeneous unmanned aircraft systems (UAS). The role of the team is to provide complete coverage (sensor data or image acquisition) of a user designated area within a specified period. A two stage planner is chosen so that vehicle maneuver constraints can be satisfied in...
The sole means for conventional multirotor UAVs to achieve horizontal translation motion is by inducing changes in vehicle attitude. The lack of horizontal force control not only disallows full controllability in all 6 Degrees of Freedom (DoFs), but also limits the set of possible control solutions. One way of achieving horizontal force control is by mounting the rotors of a UAV under a fixed amount...
This paper presents an algorithm for improving navigation performance of an Unmanned Aerial Vehicle (UAV) in GPS-challenging environments, which exploits aiding measurements from one or more cooperative UAVs flying under full GPS coverage. In particular, sensor fusion is based on an Extended Kalman Filter that integrates measurements from onboard inertial sensors and magnetometers, available GPS pseudoranges,...
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