A challenging issue associated with fixed-wing Unmanned Aerial Vehicles (UAVs) is that these vehicles are often not appropriate for operating effectively in limited airspace. This problem emerges especially in urban environment where the usage of a runway is not possible, and UAVs usually have to fly at a relatively low speed and altitude. The development of a vertical take-off and landing (VTOL) fixed-wing plane is a promising trend which hopefully will solve this issue. This paper presents the design process of an unmanned vertical take-off and landing aircraft including prototyping of the airframe construction and mathematical modeling as well as computational fluid dynamics (CFD) simulations. The designed system is to be a hybrid platform, for which different operating modes correspond to the vertical flight, transition, and spatial flight in the airframe system. The paper discusses an iterative design process of the platform with emphasis on CAD design and aerodynamic analysis for particular flight modes. The operating prototype is presented and future plans for platform improvement are discussed.

The paper focuses on the problem of detecting unmanned aerial vehicles that violate restricted airspace. The main purpose of the research is to develop an algorithm that enables the detection, identification and recognition in 3D space of a UAV violating restricted airspace. The proposed method consists of multi-sensory data fusion and is based on conditional complementary filtration and multi-stage clustering. On the basis of the review of the available UAV detection technologies, three sensory systems classified into the groups of passive and active methods are selected. The UAV detection algorithm is developed on the basis of data collected during field tests under real conditions, from three sensors: a radio system, an ADS-B transponder and a radar equipped with four antenna arrays. The efficiency of the proposed solution was tested on the basis of rapid prototyping in the MATLAB simulation environment with the use of data from the real sensory system obtained during controlled UAV flights. The obtained results of UAV detections confirmed the effectiveness of the proposed method and theoretical expectations.

The aim of this research is to examine the different control strategies for the unmanned aerial vehicles (UAV). The control task is formulated as an angular stabilization of the four rotor platform, and also as a tracking problem of chosen state variables. The PID algorithm has been considered in three structures in respect of the optimal control signal applied to the actuators. For better performance of the quadrotor in hover mode the cascade control system has been proposed. The simulation results of attitude control with different PID controller architectures are presented, and confirm the effectiveness of the proposed control structure and theoretical expectations. Moreover, the design and the practical realization of the control architecture on the experimental aerial vehicle are described. The fast prototyping method together with Matlab/Simulink software and DAQ hardware are used for both evolution and validation of control algorithms. The capacity of the attitude stabilization system is important in the development process of more advanced functionality of autonomous flying vehicles; therefore it needs to be highlighted and taken into careful consideration.

The propulsion system plays a key role in each unmanned aerial vehicle. Considering different multirotor platforms we may observe that mostly the dynamics and performance of the particular vehicle is strictly depended on the drive unit. In this paper we focus on the problem of modeling and identification of the propulsion system consisting of an electronic speed controller, electric brushless direct current motor and propeller. We propose a multiple-input and multiple-output nonlinear model of the propulsion unit based on the block oriented modeling with the static nonlinearities at the input and linear dynamical part at the output. Such model enhanced with the aerodynamics theory of a propeller should be suitable and detailed enough to provide the simulation, control algorithms prototyping and solution verification under the circumstances of designing the vertical take-off and landing unmanned platform.

Altitude measurement with a high reliability is a very difficult issue not because of the sensors complexity and requirements but due to the quality of the signals and fast changing environment conditions. In this paper we focus on the problem of the vertical movement measurements of the unmanned aerial vehicles and approach to the future control algorithms implementation. Two-sensors algorithm has been proposed on the basis of the data fusion from the pressure sensor and ultrasonic range finder.