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The use of tethered Unmanned Aircraft Systems (UAS) in aerial robotic applications is a relatively unexplored research field. In this work a numerically efficient implementation of a sigma-point Kalman filter is applied to the attitude and relative position estimation of a small-size tethered unmanned helicopter. For that purpose, the state prediction is performed using a kinematic process model driven...
A fault tolerant cooperative control (FTCC) strategy for a team of an unmanned aerial vehicle (UAV) and unmanned ground vehicles (UGVs) in the presence of actuator faults are investigated in this paper. A combination of a linear model predictive control (MPC) and input-output feedback linearization is implemented on each UGV, while a combination of a sliding mode control and linear quadratic regulator...
This paper details the design and performance assessment of a unique collision avoidance decision and control strategy for autonomous vision-based See and Avoid systems. The general approach revolves around re-positioning a collision object in the image using image-based visual servoing, without estimating range or time to collision. The decision strategy thus involves determining where to move the...
In this paper, a leader-follower formation control of multiple unmanned aerial vehicles (UAVs) design methodology is proposed to keep the desired formation, while simultaneously deal with the potential collision and actuator faults. The proposed formation control is divided into outer-loop and inner-loop controllers. First, a leader-follower control structure is constructed as the outer-loop controller...
This paper presents the control during take-off, transition and straight and level flight of a convertible aircraft based on Gain-Scheduling technique. The vehicle motion equations are deduced using Newton-Euler formulation. The lift, drag and pitch moment coefficients are modeled for angle of attack variations between one hundred eighty degrees and minus one hundred eighty degrees based on preliminary...
This paper is about a control design for the lateral-directional dynamics of a fixed wing aircraft. The objective is to command the lateral-directional dynamics to the equilibrium point that corresponds to a coordinated turn. The proposed control is inspired by the total energy control system technique; with the objective of mixing the ailerons and the rudder inputs. The control law is developed directly...
This paper presents a trajectory tracking controller for multi-rotor UAVs to improve their flight performance in the presence of various uncertainties. The proposed tracking system consists of a velocity guidance law based on relative distance and an L1 adaptive augmentation loop for tracking velocity commands. In the proposed structure, the desired velocity generated by the guidance law is the reference...
A conceptual third party risk (TPR) model is developed, implemented, and tested to demonstrate the capability of determining the risk to the population in a metropolitan city exposed to personal aerial vehicles (PAVs) and unmanned aerial vehicles (UAVs) traffic operations. The conceptual model that is primarily based on the methodology and experience of risk modelling for conventional aircraft is...
In this paper, we explore the concept of a tracker-sensor feedback loop, i.e., how tracker output can inform sensor processing, and investigate whether it can improve multiple target tracking performance and enable stationary object detection in video. Our implementation of the tracker-sensor feedback loop is based on the Gaussian Mixture Models (GMM) foreground detector. We modify the standard GMM...
This paper provides experimental validation of a uniformly semi-globally exponentially stable (USGES) non-linear observer for estimation of attitude, gyro bias, position, velocity and acceleration of a fixed-wing Unmanned Aerial Vehicle (UAV). The available sensors are an Inertial Measurement Unit (IMU), a Global Positioning System (GPS) receiver, a video camera, and an inclinometer. The UAV is flown...
The objective of this research is to demonstrate how adaptive wings improve the overall performance of conventional micro air vehicles (MAVs). This will allow MAVs to fulfill missions with different range and endurance requirements, and therefore to perform a wider range of missions than conventional MAVs. These adaptive wings are achieved with the use of macro-fiber composites devices, a low-cost,...
Fixed wing Unmanned Aerial Vehicles (UAVs) are an increasingly common sensing platform, owing to their key advantages: speed, endurance and ability to explore remote areas. While these platforms are highly efficient, they cannot easily be equipped with air data sensors commonly found on their larger scale manned counterparts. Indeed, such sensors are bulky, expensive and severely reduce the payload...
Small UAS have highly constrained payload capacity, which dictates what sensors and transmitters can be selected as part of the electronics suite. We present elements of a sense and avoid (SAA) system which enables UAVs to track intruder aircraft not broadcasting ADS-B. Such SAA methods help assure safety in cases of late encounters with non-cooperative threats. This paper presents an approach to...
Among the main sub-areas covering the cooperative control problem of Unmanned Aerial Vehicles (UAVs), formation flight has attracted great interest and has been widely investigated. The main purpose of the formation flight control is to establish a desired shape of formation for a group of vehicles by controlling the positions of each vehicle. The present paper deals with the problem of position formation...
Cooperative and non-cooperative Sense-and-Avoid (SAA) capabilities are key enablers for Unmanned Aircraft Vehicle (UAV) to safely and routinely access all classes of airspace. In this paper state-of-the-art cooperative and non-cooperative SAA sensor/system technologies for small-to-medium size UAV are identified and the associated multi-sensor data fusion techniques are introduced. A reference SAA...
This work studies a longitudinal high incidence flight envelope dynamic model for use in a convertible tilt-body vehicle designed for indoor/outdoor environments. The model assumptions are chosen so that a singularity-free nonlinear differential equation system is obtained. The model is complex enough to predict wind tunnel experiments yet simple enough to be described by analytical expressions (instead...
This paper presents the key design features, the numerical simulations and the experimental ground/flight test activities performed to verify the functionalities of an obstacle detection and avoidance system suitable for various classes of manned and unmanned aircraft. The Laser Obstacle Avoidance and Monitoring (LOAM) system is proposed as one of the key non-cooperative sensors adopted for avoiding...
This paper proposes a control strategy for the quadrotor helicopter based on the Total Energy Control System (TECS) approach. Assuming that the rotational dynamics control loop is faster than the translational dynamics control loop, a TECS based control strategy is designed for the translational dynamics. The performance of the proposed control strategy is verified experimentally.
UAVs are used in several remote applications. While performing a mission, electro-mechanical faults can occur which requires the UAVs to land quickly and safely. Landing in emergency conditions is a time critical problem, where, the UAV needs to find a landing site and plan a path to the selected site that satisfies some safety criterion in a given time. In this paper, we use terrain information from...
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