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This paper presents a neural network based model reference adaptive controller (MRAC) for the control of a fixed-wing unmanned aerial vehicle (UAV). An adaptive neural network is trained using the error between the UAV response and the desired response as given by the reference model. The design of a suitable reference model for the desired aircraft performance is investigated and developed. Unknown...
In this work, we present an autonomous control system to perform aerobatic maneuvers with an agile fixed-wing UAV. The control system is strongly based on the underlying physics of the aircraft, thus allowing simple control techniques to work well through the full range of flight conditions undergone in aerobatic maneuvers. Moreover, this single control system is capable of performing a wide variety...
A modern class of small fixed-wing unmanned aerial vehicles are physically capable of performing exceptional aerobatic maneuvers. This paper presents a methodology for including one of the more functional of these maneuvers, the knife-edge, in motion planning. This is achieved by separating the top-level motion planner from the dynamics and control of the knife-edge maneuver. By coupling feedback...
Small unmanned aircraft systems (UAS) typically do not offer the redundancy typical in commercial aviation due to budget and weight limitations. UAS, therefore, have a nontrivial probability of encountering a scenario in-flight that requires an emergency landing. For fixed-wing UAS, one of the most common in-flight emergencies is a total loss of engine or motor thrust, necessitating that the UAS glide...
We develop a theoretical power consumption model for multi-rotor Unmanned Aircraft Systems (UAS), estimate the model parameters, and validate it by flying an IRIS+ quadrotor UAS and measuring its energy consumption experimentally. The model is derived from the helicopter literature. Such models are required to create UAS flight planning systems.
Existence of modeling errors, external disturbances, and inaccurate design assumptions make robustness a desired property for any control system in real-life applications. Linear robust controllers are widely seen as acceptable solutions when systems are controlled close to known equilibrium points and a known trajectory. Unfortunately, linear robust control designs become partially ineffective when...
Simulation plays an essential role in the development of complex systems. This paper reports on the development of a simulation infrastructure for a fleet of UAVs conceived to probe clouds, using an adaptive sampling scheme that calls for cloud mapping and trajectory planning. The mission is presented, the global approach to solve it and the ensemble of required processes are sketched. An overall...
This paper presents the design and implementation of a cost-effective, lightweight, yet power efficient tail-sitter Vertical Take-off and Landing (VTOL) unmanned aerial vehicle (UAV). The UAV consists a pair of wings for efficient level flight and four rotors for attitude control. The aerodynamic and mechanical configurations of the UAV are designed and implemented from scratch to meet the required...
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 methodology to locate a target using measurements of its signal strength is discussed in this paper. One of the main challenges lie in locating the source when it is moving or has time varying signal strength. In this paper two different strategies to locate and intercept a time varying and moving source by an Unmanned Aerial Vehicle (UAV) is presented. In the first strategy the UAV traverses a...
This work presents the flight test validation of an autonomous nano quadrotor called Crazyflie 2.0 in arbitrary trajectory tracking. The complexity of the control tasks were due to the low rigidity and high flexibility of propellers and airframe components, high sensitivity of vehicle inertial dynamic model to the battery location, uncalibrated motors, and unsteady battery depletion rate. Keeping...
Tilt rotor unmanned aerial vehicle (TRUAV) with ability of hovering and high-speed cruise has attached much attention, but its transition control is still a difficult point because of varying dynamics. This paper proposes a multi-model adaptive control (MMAC) method for a quad-TRUAV, and the stability in the transition procedure could be ensured by considering corresponding dynamics. For safe transition,...
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...
The aim of this paper is to provide a mathematical model for a convertible unmanned aerial vehicle that combines the capabilities of a flying wing and tricopter with tilt rotors. This article presents the mathematical model for airplane and tricopter modes as well as the way they are related during the transition phase. Also is presented a control strategy to hover flying. Finally, it is presented...
This paper describes the 4-Dimensional Trajectory (4DT) optimisation algorithm implemented to avoid a variety Global Navigation Satellite System (GNSS) signal degradations predicted by Avionics Based Integrity Augmentation system (ABIA). The paper focusses on descent and initial curved GNSS approach phases in a dense Terminal Manoeuvring Area (TMA) scenario, with multiple aircraft converging on the...
The objective of this paper is to demonstrate the application of optimal control for generating dynamically constrained minimal time trajectories in micro unmanned airships. By design, airships are generally underactuated and underpowered limiting their maneuvering capabilities. Using a simplified dynamic model derived with experimentally derived coefficients, two trajectory planning simulations are...
The aim of this study is to investigate methods for computing the position of an intruder aircraft relative to an observer aircraft with onboard stereo cameras. To focus on relative position estimation rather than the intruder aircraft detection through image processing, the first phase is to generate camera images given the relative position information. This process uses a simple pinhole camera...
Complexity is a measure of the difficulty that a particular air traffic situation represents to Air Traffic Controller (ATCo). This measure impacts on ATCo workload, which is an important factor for defining airspace capacity. This paper presents an evaluation of the impact of the insertion of Remotely Piloted Aircraft (RPA) on safety levels within a non-segregated airspace based on the calculation...
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...
This paper deals with monocular image-based aircraft Sense and Avoid for small UAVs. After summarizing previous results of the authors it proposes a complete solution which calculates time to closest point of approach, relative closest point of approach (CPA) and the direction of intruder at CPA. These parameters are enough to make a collision decision and design the avoidance maneuver. The applicability...
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