Firstly, the Rankine sources are distribut ed in inner domain and transient Green functions are used in outer domain, and the unsteady and steady motions as well as the effects of steady motion on unsteady motion are adequately considered in this hybrid panel method. dimensional hybrid method is proposed for the direct numerical simulation of parametric roll. In order to deal with the problem on the prediction of parametric roll in random waves, one three. It is regarded as one of the most important stability failure modes in the second intact stability criteria, which are under development by the International Maritime Organization (IMO). Parametric roll in irregular head waves is one of the critical risks for the safety when a ship sails in the sea. No severe fades were observed that could not be attributed to earth reflection phenomena. Theoretical frequency dependent diffraction slopes calculated for signal strength beyond the horizon are closely duplicated in the data. The indicated lobe rates and reflection coefficients closely compare with the theoretical with some scatter primarily due to rapid unavoidable excursions of aircraft altitude. The recorded interference lobe structure envelope compares favorably with the theoretical except for a maximum range foreshortening probably due to a substandard refractive condition. and, to a less extent, the effects of lower atmosphere refraction. Analyses include primarily those phenomena due to earth reflections. Signal strength for frequencies of 250, 1000, and 3300 mc was recorded simultaneously in a receiving aircraft as a function of separation distance from a transmitting aircraft at 1000 feet altitude. View full-textĪir-to-air tropospheric one-way radio wave propagation tests over smooth fresh water are described and the resulting data analyzed. The presented theoretical and experimental techniques can have a great impact on the safe deployment and effective operation of a wide variety of morphing and inflatable structures such as morphing aircraft, solar sails, inflatable wings, and large antennas. The structure/sensor network system is tested under various static conditions to determine the response characteristics of the proposed sensor network as compared to other conventional sensor systems. The developed theoretical model is validated experimentally using a prototype of a variable cambered span morphing structure provided with a network of distributed sensors. The strain map ensures that the structure is not loaded excessively to adversely affect its service life. The deflection and shape information are required to ascertain that the structure is properly deployed and that its surfaces are operating wrinkle-free. outputs are wirelessly transmitted to the command unit to simultaneously compute maps of the linear and angular deflections and maps of the strain distribution of the entire structure. The proposed development is based on the non-linear theory of finite elements to extract the transverse linear and angular deflections of a plate-like structure. This paper presents the development of the theoretical basis for the design of sensor networks for determining the 2-dimensioal shape of morphing structures by monitoring simultaneously the bending and twist deflections. The results of numerical simulation of UAV motion with the regulator obtained in the MATLAB environment are presented in the article. The main advantages of the regulator obtained are: the system is stable within a broad range of input values by varying the regulator coefficients, you can easily select the desired characteristics of control quality. The resulting control takes into account the nonlinearity of the object and depends on the entire state vector. The algorithm of backstepping consists in making each integrator of the object stable by adding the feedback computed from this algorithm. According to this method, the task of developing a control law for the entire system is divided into a sequence of respective subtasks to lower-order subsystems. To synthesize the control and stabilization systems, the backstepping method is applied.

It is proposed to form the height control law on the basis of the thrust moment, which gives the advantage of stabilizing the angular velocity and the pitch angle.

The thrust motor is mounted on the UAV so that the thrust is directed along the OX axis in the OXY plane. Direct control is provided by the thrust motor. A mathematical model of UAV motion is described in a body-axis coordinate system. An UAV is described, its scheme is shown, the forces and moments acting on it in the longitudinal plane are examined.

Synthesis of the height control system for an unmanned aerial vehicle (UAV) with a soft wing, like a paraglider or a powered parachute, is considered in the article.

Paraglider models typesy