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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...
A simple strategy to saturate the reference velocities when guiding an Unmanned Aerial Vehicle (UAV) to accomplish trajectory-tracking tasks is proposed. Such a controller has two parts: a kinematic controller to generate reference velocities for the vehicle and a state-variables change with a PD controller to guarantee the tracking of such velocities. This characterizes a cascade controller and guarantees...
In this paper, we investigate the problem of the dynamics of a quadrotor unmanned aerial vehicle undergoing impact with its environment. This work is motivated by the fact that operation of UAVs (manual or autonomous) carries with it a significant risk of collision with surrounding objects, particularly in unknown, unstructured environments. To make small UAVs more viable and expand their autonomy,...
In this paper we propose a model of zero-sum differential games (ZSG) to perform the formation flight of a group of three fixed-wing Unmanned Aerial Vehicles (UAVs). The dynamics of these UAVs are described in the linearized model around nominal values. For the formation strategy, the game scheme for one of the UAVs acts as the leader vehicle following a freely designed trajectory meanwhile the two...
This paper addresses simulation results about the altitude control of a quad-rotor unmanned flying vehicle (UAV) in the presence of uncertainty like wind gust. A sliding mode control was proposed, the gain of control can be decreased and, as a result, the chattering amplitude is reduced. The objective is to introduce an adaptation in the control law in order to decrease the gain to the minimal value...
This paper presents the modeling, the design of control laws, for Euler angles and altitude, and their implementation. The proposed controller is based on the backstepping procedure and uses a state feedback linearizing technique to guarantee tracking of the desired Euler angles and altitude on the ornithopter. The provided controller provides exponential convergence to the desired values. Numerical...
Multirotor aerial vehicles are extensively employed in applications requiring a stationary surveillance platform to monitor a situation on the ground for a specific duration. In most cases, these systems are small in size and weigh < 10Kgs. This paper presents a design methodology employed to develop a multirotor system exceeding the conventional size and weight category. The study includes modelling...
Airships present many interesting opportunities for transport, surveillance and inspection but have seen little to no use in commercial or military unmanned applications. Generally underpowered, underactuated, and large in size, airships express difficulties in adverse atmospheric conditions or situations requiring rapid or precise maneuvers. In this paper, a miniature unmanned airship with a moving...
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