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.     

“我们相信ARJ21是一个很好的项目”——访罗克韦尔·柯林斯公司商务和支线系统部副总裁兼总经理丹尼·海格森

记者：请您介绍一下罗克韦尔·柯林斯公司在ARJ21-700项目中的参与情况。 丹尼·海格森：作为ARJ21-700项目的19家供应商之一，我们负责为ARJ21-700飞机提供一整套的航电设备，其中涵盖了通信、导航、飞控以及监视各个子系统。     

Testing the Stability of the Fine Structure Constant in the Laboratory

In this review we discuss the progress of the past decade in testing for a possible temporal variation of the fine structure constant α. Advances in atomic sample preparation, laser spectroscopy and optical frequency measurements led to rapid reduction of measurement uncertainties. Eventually laboratory tests became the most sensitive tool to detect a possible variation of α at the present epoch. We explain the methods and technologies that helped to make this possible.     

The Mode of Gravitational Orientation for the International Space Station

The results of the determination of the uncontrolled attitude motion of the International Space Station during its unmanned flight in 1999 are presented. The data of onboard measurements of three components of the angular velocity are used for this determination. These data covering an interval of slightly less than one orbit were jointly processed by the least squares method, by integrating the equations of motion of the station relative to its center of mass. As a result of this processing, the initial conditions of the motion and the parameters of the mathematical model used were estimated. The actual motion of the station has been determined for 20 such intervals during April–November. Throughout these intervals, the station rotated about the axis of the minimum moment of inertia, the latter executing small oscillations relative to the local vertical. Such a mode, known as the mode of gravitational orientation of a rotating satellite or the mode of generalized gravitational orientation, was planned before the flight. The measurements were made to verify it. The quasistatic component of the microaccelerations aboard the station is estimated for this mode.     

An Enduring Partnership Professional, Cultural, Personat

20 years ago, in September 1987, an adventure began which was unique in aviation/aerospace publishing. That adventure led to a multimedia partnership which has grown stronger every year since 1987 and developed into a lasting friendship and global business alliance that continues today.     

Right ventricular tissue Doppler assessment in space during circulating volume modification using the Braslet device

Introduction: This joint US–Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M (Braslet) occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, effectively reducing the volume in central circulation. The methodology was tested at the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the cuffs, as well as to modified Valsalva and Mueller maneuvers. This case study examines the use of tissue Doppler (TD) of the right ventricular (RV) free wall. Results: Baseline TD of the RV free wall without Braslet showed early diastolic E′ (16 cm/s), late diastolic A′ (14 cm/s), and systolic S′ (12 cm/s) velocities comparable with those in normal subjects on Earth. Braslet application caused 50% decrease of E′ (8 cm/s), 45% increase of A′, and no change to S′. Approximately 8 beats after the Braslet release, TD showed E′ of 8 cm/s, A′ of 12 cm/s, and S′ of 13 cm/s. At this point after release, E′ did not recover to baseline values while l A′ and S′ did recover. The pre-systolic cross-sectional area of the internal jugular vein without Braslet was 1.07 cm², and 1.13 cm² 10 min after the Braslet was applied. The respective cross-sectional areas of the femoral vein were 0.50 and 0.54 cm². The RV myocardial performance Tei index was calculated by dividing the sum of the isovolumic contraction time and isovolumic relaxation time by the ejection time ((IVCT+IVRT)/ET); baseline and Braslet-on values for Tei index were 0.25 and 0.22, respectively. Braslet Tei indices are within normal ranges found in healthy terrestrial subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of the study. Conclusions: TD modality was successfully implemented in space flight for the first time. TD of RV revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower extremity interstitial and vascular space after only 10 min of application. This report demonstrates that Braslet application has an effect on RV physiology in long-duration space flight based on TD, and that this effect is in part due to venous hemodynamics.     

Dynamics investigation of the two-channel automatic system controlling the mirror of aircraft-based surveillance-search system

The mathematical model of the control system for the mirror having a cardan suspension, installed aboard an aircraft is investigated. Control algorithms that provide the required dynamic properties in scanning, guidance and tracking modes were synthesized. We analyze dynamics of the control system for a mirror with regard to nonlinearities in controllers using the computer-aided simulation.     

Method of constructing a neural regulator for the automatic one-dimensional control of a technical object

The paper discusses a neural regulator for controlling technical objects described by a second-order differential equation. The results of experimental studies are presented on selecting a number of hidden layers, a number of neurons in layers, and use of the neural regulator constructed.     

Large-scale electric fields and currents and related geomagnetic variations in the quiet plasmasphere

At the end of the sixties it became obvious that two-dimensional dynamo models can explain nearly all facts, which had been found morphologically for mean annual Sq-fields. During the recent decade new or improved methods to measure electric fields (e.g. incoherent scatter facilities) and to investigate great data files have been developed. New informations received with these methods about the existence of regular variations of the Sq-field in dependence on season and universal time and about the electric field have been summarized in Section 2. All attempts to describe also these variations with a two-dimensional dynamo model did not lead to any success, but showed a strong theoretical over-estimation of the asymmetries. Therefore, it must be concluded that three-dimensional plasmaspheric current systems, taking into consideration the coupling between both hemispheres along the high-conducting magnetic field lines, are needed in order to explain the regular variations of the Sq -field. The basic equations for two- and three-dimensional dynamo models, different methods for the solution of these equations and the resulting models from different authors are compiled and discussed (Section 3).Based on all morphological and theoretical results a plasmaspheric-ionospheric current system has been constructed and some properties of the plasmaspheric field-aligned current distribution, have been derived.