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Current state-of-the-art vision-based sense and avoid systems based on morphological and hidden Markov model filtering require the manual selection of static (timeinvariant) detection thresholds. Manually selecting suitable static detection thresholds is challenging (and currently requires highly trained operators) because it involves balancing tradeoffs between detection and false alarm performance...
In the context of optical-aided navigation and visual Simultaneous Localization And Mapping (SLAM) for satellite-denied aircraft navigation, this paper extends the monocular SLAM approach by the use of multiple sensors with different viewing directions. Downward optical sensors see other movements than forward-looking cameras, hence it is straightforward to combine the benefits of both. This combination...
This paper addresses the modeling, identification and adaptive sliding mode control for a quadrotor micro aerial vehicle. In order to obtain a compact kinematics and dynamics representation, the spatial vectors convention is used, making more efficiently the model computation by reducing the number of algebraic operations. Identification of parameters such as inertia moments, thrust and torque of...
This paper proposes a new path following methodology combining with a obstacle avoidance scheme for unmanned quadrotor helicopter (UQH) capable of working in the cluttered and hazardous environments. A new cross-track error prediction based mechanism, where the cross-track error is estimated by utilizing the extend Kalman filter (EKF), is first developed for the path following scheme. Then, the UQH...
Unmanned networked multirobot systems have the potential to accomplish complex field tasks with minimum human intervention. Motion coordination of vehicles that operate in different domains (land, sea, air) is one of the problems that need to be addressed to achieve such a goal. This article presents a representation method based on dual quaternions for leader- follower formation control architectures...
Recently, it was shown that an hexagon shaped hexarotor vehicle with tilted rotors, is capable of fault tolerant attitude and altitude control. In this work, we propose a strategy to select the signals commanded to each rotor in order to achieve a desired torque and vertical force. The proposed strategy is optimal in the sense that minimizes the maximum force exerted by the rotors. A comparison with...
We consider a Persistent Intelligence, Surveillance and Reconnaissance (PISR) routing problem, which includes collecting data from a set of specified task locations and delivering that data to a control station. Each task is assigned a refresh rate based on its priority, where higher priority tasks require higher refresh rates. The UAV team's objective is to minimize the maximum of the delivery times...
Small consumer unmanned aircraft systems (sUASs) have been involved in many security incidents recently. Current defense methods have serious limitations because they mostly try to physically capture an sUAS or jam its communications and its GPS signals to trigger its fail-safe features. While physical methods are usually unscalable and often slow in response, the default fail-safe features can be...
In this paper we study the localization and tracking of a radio frequency (RF) emitting target using multiple unmanned aerial vehicles (UAVs) over a large scale environment. Although localization of RF emitting targets using multiple measurements is a well studied problem, the standard approaches become inefficient when the signal power is uncertain and there is significant noise in the received signal...
A miniature in-situ CH4 concentration measurement instrument based upon tunable laser spectroscopy (TLS) was developed and applied in numerous field campaigns. The instrument, a 3.4 μm laser spectrometer developed at NASA Jet Propulsion Lab (JPL), is lightweight (250g), low power (< 8 W), and high sensitivity (10 ppb s−1). The payload was further developed and integrated onto a small UAV at UC...
A real-time vision-based object tracking system embedded in a quadrotor is presented in this paper. The integrated system is expected to enable the quadrotor to track a target object and keep with a fixed distance. A robust object tracking method via improving Kernelized Correlation Filters algorithm is proposed to achieve accurate visual tracking. In addition, a PID controller is applied to utilize...
A sensitivity analysis is presented on the influence of the weight, altitude and speed of battery-powered sUAS on the resulting stall speed, endurance and range. To aid in the determination of the aircraft performance prior to flight, a method is being brought forth that quantifies the impact of these mission parameters. As a case study the P31015 sUAS is used. The P31015 is a concept model of a battery-powered...
This paper investigates the feasibility of a longrange inspection mission of railways by UAVs from a risk point of view. Ground risk for population of inhabited areas is assessed for such a mission and compared to the ones of shorter “elementary” flights for which flight authorizations have already been obtained or would be easy to obtain. By this comparative approach, the feasibility of the full...
This paper proposes an integrated system architecture composed by a custom-designed lightweight Ground Penetrating Radar (GPR) and a novel method for low-altitude autonomous flight called Backstepping+DAF. Simulations and experimental results are carried out to evaluate how steady flight is achieved by means of the proposed flight controller that consequently enables the GPR detection of buried objects...
The primary focus of the work presented in this paper is a proof-of-concept study of a novel electro-thermal- based autonomous icing protection solution (IPS) for small unmanned aircraft. The solution includes a central control unit, where several control algorithms, ensure temperature control of electro-thermal sources, applied to exposed aircraft surfaces. The solution includes three different control...
Safety and reliability (also referred to as airworthiness) are well-known factors of Unmanned Aerial Vehicle (UAV) operations, and significant effort has been put into maintaining and improving them for everyday UAV users. Cyber-security, on the other hand, gained attention only recently. Currently, a malicious user can relatively easily disturb operation or even seize control of the most popular...
Although flapping-wing micro aerial vehicles have become a hot topic in academia, the knowledge we have of these systems, their force generation mechanisms and dynamics is still limited. Recent technological advances have allowed for the development of free flight test setups using on-board sensors and external tracking systems, for system identification purposes. Nevertheless, there is still little...
This paper presents the design, development and testing of a 4-DoF aerial manipulator for bridge inspection, where the arm is placed at the upper part of the multirotor body. The manipulator joints are equipped with a compliant mechanism that allows the contact with the environment reducing the influence over the platform stability. The transmission mechanism consists of two pairs of springs and a...
This paper presents an approach to fault detection and isolation for a network composed by multiple Unmanned Aerial Vehicles (UAVs) flying in formation. The methodology consists on the use of a bank of unknown input observers (UIO) that runs in each UAV in order to generate a set of residual signals, that will be used to perform the detection. To this end, we consider an extended version of the unicycle...
This paper investigates aerodynamic performance improvements of formation flight at transonic speeds for a medium size Unmanned Aerial Vehicle (UAV). The metric for assessing the aerodynamic improvement of formation flight is the computed drag. The total drag for each formation configuration is compared with a single UAV, where a final drag reduction percentage is estimated. The evaluation of the...
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