Method of designing a neural controller for the automatic lateral control of unmanned aerial vehicles

The paper discusses a method of designing the neural controller for two-channel control of a technical object by an example of the roll and yaw control depending on deviations, velocities and accelerations of their variation.     

The adjustment of the mathematical model accuracy of the gas-hydraulic flight control actuator power circuit of an aircraft

The methodology is proposed and the mathematical model is developed for the purpose of numerical simulation of the power circuit of the gas-hydraulic actuator with displacing power source for the gimbaled nozzle control. It provides the highest power efficiency factor of the actuator as a part of aircraft by means of pulling together the profiles of available and required power.     

Determination of maximum deflection in transverse bending of parallelogram plates using the conformal radiuses ratio

A problem of transverse bending of elastic isotropic parallelogram plates under the action of uniformly distributed load is considered. The plate sides are either pivoted or rigidly restrained. To determine the value of maximum plate deflection, it is proposed that an interpolation technique with respect to form factor be used; and as a geometrical argument, an inner-outer conformal radius ratio can be applied instead of the form factor.     

Excitation of Pc5 pulsations of the geomagnetic field and riometric absorption

We consider in detail the intense Pc5 pulsations of the magnetic field, riometric absorption, and electron fluxes occurred on the recovery phase of the strong magnetic storm on November 21, 2003. The global structure of these disturbances is studied using the world network of magnetometers and riometers supplemented by the data of particle detectors onboard the LANL geosynchronous satellites. The local spatial structure is investigated according to data of the regional network of Finnish vertical riometers and of stations of the IMAGE magnetic network. Though a certain similarity is observed in the frequency composition and time evolution of the variations of magnetic field and riometric absorption, the local spatial structure of these oscillations turns out to be different. It is suggested that these variations can be manifestations of oscillatory properties of two weakly connected systems: the magnetospheric MHD waveguide/resonator and the system cyclotron noise + electrons. The recorded Pc5 oscillations are, presumably, a result of excitation of the magnetospheric waveguide on the morning and evening flanks of the magnetosphere. At high velocities of the solar wind this waveguide can appear in a metastable state. Not only jumps in the solar wind density, but injection of electrons into the magnetosphere as well, can serve as a trigger for the waveguide excitation.     

Analysis of the spacecraft vertical landing dynamics on the platform with crash legs

This paper proposes a novel landing gear for spacecraft that allows a weight reduction due to using deformable crash legs. Numerical simulation of the landing process was performed.     

Flux and isotopic composition of helium in the ancient solar wind

The isotopic composition and concentrations of helium are investigated in 9 samples taken from different depths of a soil column delivered by the Luna-24 mission. It is demonstrated that, with allowance made for random errors, the isotopic composition of helium remains invariable. The concentrations of helium are subject to considerable variations, the increases and decreases relative to the average value reaching a factor of 1.5–2. Assuming that the full length of the soil column was formed due to long-term accumulation of lunar clastic rocks (regolith), based on measurements of cosmogenic isotopes, a method of determining the rate of regolith accumulation has been developed, as well as a method of determining the age of the column soil samples. It is found that the rate of regolith accumulation is variable, and it changes over the column length within the limits (0.2–0.8 cm)/10⁶ years. The range of the time for formation of the investigated part of the column is 100–600 million years. The observed decreases of concentration (at 250 and 600 million years) can be associated with both solar and lunar processes. In particular, a possibility of diffusion losses of helium due to the mechanism of jump-like diffusion is discussed, and diffusion parameters are found. A comparison of time periods of the observed variations in the solar wind with paleontological epochs and periods is made.     

Rotational evolution of planetary systems under the action of gravitational and magnetic perturbations

Dynamics of planets around other stars that demonstrate a variety of possible characteristics is of interest from the point of view of realization of new scenarios of evolution which have not been realized in the Solar System. We consider the rotational evolution of exoplanets under the action of gravitational perturbations and magnetic disturbances using the methods of quality analysis and theory of bifurcation of multiparametric differential equations that describe evolution of non-resonant rotation of a dynamically symmetric planet magnetized along its symmetry axis. We analyze 64 phase portraits describing the evolution of angular momentum vector L for all possible values of planet parameters. The values of parameters are determined for the case when the direct rotation of a planet is changed for its retrograde rotation.     

The International DORIS Service (IDS): Toward maturity

DORIS is one of the four space-geodetic techniques participating in the Global Geodetic Observing System (GGOS), particularly to maintain and disseminate the Terrestrial Reference Frame as determined by International Earth rotation and Reference frame Service (IERS). A few years ago, under the umbrella of the International Association of Geodesy, a DORIS International Service (IDS) was created in order to foster international cooperation and to provide new scientific products. This paper addresses the organizational aspects of the IDS and presents some recent DORIS scientific results. It is for the first time that, in preparation of the ITRF2008, seven Analysis Centers (AC’s) contributed to derive long-term time series of DORIS stations positions. These solutions were then combined into a homogeneous time series IDS-2 for which a precision of less than 10 mm was obtained. Orbit comparisons between the various AC’s showed an excellent agreement in the radial component, both for the SPOT satellites (e.g. 0.5–2.1 cm RMS for SPOT-2) and Envisat (0.9–2.1 cm RMS), using different software packages, models, corrections and analysis strategies. There is now a wide international participation within IDS that should lead to future improvements in DORIS analysis strategies and DORIS-derived geodetic products.     

Numerical modeling of inhomogeneous orographic wave influence on planetary waves in the middle atmosphere

Parameterization of dynamical and thermal effects of stationary orographic gravity waves (OGWs) generated by the Earth’s surface topography is incorporated into a numerical model of general circulation of the middle and upper atmosphere. Responses of atmospheric general circulation and characteristics of planetary waves at altitudes from the troposphere up to the thermosphere to the effects of OGWs propagating from the earth surface are studied. Changes in atmospheric circulation and amplitudes of planetary waves due to variations of OGW generation and propagation in different seasons are considered. It is shown that during solstices the main OGW dynamical and heat effects occur in the middle atmosphere of winter hemispheres, where changes in planetary wave amplitudes due to OGWs may reach up to 50%. During equinoxes OGW effects are distributed more homogeneously between northern and southern hemispheres.