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Most of the routing algorithms for unmanned vehicles, that arise in data gathering and monitoring applications in the literature, rely on the Global Positioning System (GPS) information for localization. However, disruption of GPS signals either intentionally or unintentionally could potentially render these algorithms not applicable. In this article, we present a novel method to address this difficulty...
The measurements of air-to-air channel at C-band for coexistence among multiple unmanned aircraft (UA) systems are presented. The measurement campaign was performed to clarify the channel characteristic of the air-to-air radio propagation between small UAs. This paper presents a measurement result of our campaign on radio channel characteristics in C-band held in Japan in March 2016. The received...
Small Unmanned Aircraft Systems (sUAS) are already revolutionizing agricultural and environmental monitoring through the acquisition of high-resolution multi-spectral imagery on-demand. However, in order to accurately understand various complex environmental and agricultural processes, it is often necessary to collect physical samples of pests, pathogens, and insects from the field for ex-situ analysis...
This paper presents a control strategy for two planar vertical take-off and landing (PVTOL) vehicles cooperating to transport a rigid body load without any explicit exchange of state information between them. This means that the vehicles have only access to their own state variables. The solution and stability analysis is based on a passivity approach.
This paper presents a novel pattern for the trajectories that a team of cooperative unmanned aerial vehicles (UAVs) adopt to perform an exhaustive search of mobile targets in a specified area. The proposed moving pattern also creates a safe area into which no target is able to intrude. The Progressively Spiral Out (PSO) path is developed to describe the proposed moving pattern, which can be applied...
A comparison of attitude estimation algorithms is performed to allow selection of an appropriate algorithm for a quadrotor collision recovery system. A Multiplicative Extended Kalman Filter (MEKF), an Unscented Kalman Filter (UKF), a complementary filter, an H∞ Filter, and adaptive varieties of the selected filters are chosen for comparison. The adaptive modifications to the estimation algorithms...
The usages and functionalities of Unmanned Aerial Vehicles (UAV) have grown rapidly during the last years. They are being engaged in many types of missions, ranging from military to agriculture passing by entertainment and rescue or even delivery. Nonetheless, for being able to perform such tasks, UAVs have to navigate safely in an often dynamic and partly unknown environment. This brings many challenges...
This paper proposes a novel method for corresponding visual measurements to map points in a visual-inertial navigation system. The algorithm is based on the minimization of the photometric error on sparse locations of the image region, and realizes a gain in robustness that comes from the elimination of the need of feature-extraction for correspondence. The system is compared to a standard approach...
This paper presents the design of a dual-arm aerial manipulator consisting of a multi-rotor platform with an ultra-lightweight (1.8 Kg) human-size dual arm prototype and its control system. Each arm provides three degrees of freedom (DOF) for positioning the end- effector, and two DOF for orientation. As most model-based controllers assume that joint torque feedback is available, a torque estimator...
This paper considers the disturbance observer- based distributed fault-tolerant containment control problem for longitudinal motion of multiple unmanned aerial vehicles (multi-UAVs) in the presence of actuator, sensor faults, and input saturation when only a subset of the multi-UAVs has access to the leaders. The communication network is an undirected, fixed topology and the distributed control scheme...
Unmanned Aerial Vehicle (UAV) development is a field with rising interest in recent years. One of its essential part is the autopilot, responsible for keeping the aircraft in desired flight conditions and for executing navigation tasks. Among the navigation tasks, one that stands out is the path- following operation, which guarantees that the aircraft follows a predefined trajectory. The literature...
A collision-free trajectory generation method capable of re-planning the trajectories of an unmanned aerial vehicle (UaV) can increase flight safety and decrease the possibility of mission failure. For this purpose, a Markov decision process (MDP) based algorithm combined with backtracking method, is presented to create a safe trajectory in the case of obstacles. Subsequently, a differential flatness...
This paper presents an improved dynamic output feedback image-based visual servoing (IBVS) law for a quadrotor in comparison with our previous work (“Dynamic Visual Servoing of a Rotary-wing Unmanned Aerial Vehicle Without Velocity Measurement,” in AIAA Guidance, Navigation, and Control Conference, Grapevine, Texas, January, 2017). The controller enables the quadrotor to regulate its position and...
A two-stage optimization model for flight path planning of cooperative UAVs in formation flight in the presence of polygonal obstacles and no-fly zones is proposed. Adopting a Visibility Graph (VG) approach, the virtual formation leader plans its flight path composed of circular arcs and segments connecting obstacles vertices. Then groups of obstacles, being not permeable by the flight formation without...
The SyncBoard is a reconfigurable sensor timing board that accurately records the Time of Validity (TOV) from sensors, while acting as a protocol conversion tool. It is intended to be usable by people without expertise in hardware development. To allow accurate timing, the SyncBoard has a highperformance microcontroller with a 32-bit timer clock running at a maximum of 100 MHz. By capturing the TOV...
This paper provides a rigorous steps for controller design of a novel ducted fan vehicle under actuator uncertainties and saturation. Considering uncertain actuator dynamics, a control-oriented model is proposed to provide convenience for practical control applications. A structured robust controller that stabilizes the vehicle in the presence of actuator uncertainties and external disturbances is...
This paper studies the formation tracking problem for a multi-agent system composed by a set of quadrotor UAVs. Parrot AR.Drone 2.0 quadrotors are used as the agents of the system. The proposed control strategy is designed using a time- varying version of the backstepping technique for each agent. For the implementation of the control law, it is assumed that each agent only measures the leader and...
This paper addresses a path planning problem where a marsupial system is assigned to collect a specified amount of information about a set of objects of interest while minimizing the likelihood of detection by an opponent's sensor. A marsupial system consists of aircraft (agents) with different capabilities. The agents are characterized by their velocities, information collection capabilities, and...
With the advance in technologies and applications involving unmanned aerial systems cooperation among the autonomous agents within such an unmanned system as well as preparedness for responding to adversarial threat to such a system has become of pivotal importance. A multiphase operational scenario of such cooperative and adversarial engagement, motivated by manned aerial engagement scenarios, is...
A new concept of avoidance map is introduced which can effectively execute collision avoidance among UAVs. It is based upon representation of the effect of control effort by pairs of UAVs on achievement of avoidance, thus partitioning the control effort space into avoidance and collision regions. To do this, it is demonstrated that collision avoidance can be carried out by applying constant acceleration...
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