Some scientific achievements

IFAC Symposium on Automatic Control in Aerospace

In June, 2004 IIAAT held the great scientific forum – 16^th IFAC Symposium on Automatic Control in Aerospace. About 400 participants from 25 countries, many famous scientists came to Saint-Petersburg. The Symposium covered every aspect of the dynamics, control and mission control of aeronautical and space related systems. The list of main topics is available at http://aca2004.aanet.ru

The Symposium sponsors were IFAC, IFAC Aerospace Technical Committee and European Space Agency (ESA). The following Plenary Lectures were delivered to the Symposium participants:

1. Russian space programs: achievements and prospects of automatic control applications. V. Legostaev. Korolev's rocket-space corporation “Energia”, Russia
2. On-board control and navigation system advances for the new European Earth Observation missions. P. Silvestrin, ESA. Mission and System Studies Section for Earth Observation future programs
3. Current status of Japanese aerospace programs – focusing on high speed flight demonstration. Y. Miyazawa. Control Systems Group, Flight Systems Research Center, National Aerospace Laboratory, JAXA, Japan
4. National achievements in control theory: the aerospace perspective. A. Kurzhanski, Lomonosov's Moscow State University, Russian IFAC NMO, Russia
5. Model-based fault detection and diagnosis – status and applications. R. Isermann, Institute of Automatic Control, University of Technology at Darmstadt, Germany

All papers really presented at the Symposium and shaped according to all requirements were published and offered for sale, in the form of Proceedings, by Elsevier Science Ltd, Oxford, UK under the edition of Prof. A. Nebylov.

http://aca2004.aanet.ru/main_orga.shtml

http://www.elsevier.com/wps/find/bookdescription.cws_home/708589/description#description

Theoretical methods of dynamic systems optimization

• The technique of Chebyshev-Markov problem of moments is implemented into direct and inverse problems of filtration accuracy investigation under the numerical characteristics of signals;
• The strict solution of direct and inverse statistical research problems for control systems accuracy is obtained at actions with restricted values of derivatives or generalized moments of spectral density;
• On the basis of duality principle of linear programming problems it is proved, that the extremums of control accuracy statistical factors at restricted dispersions of derivatives are reached at line spectrum of input action;
• It is proved, that the assigning of spectral-correlation characteristics of signals as numbers, instead of functions (that better corresponds to an actual volume of a priori information) in the Wiener-type filtering problems forces to consider some range of possible values of filtering accuracy factor; width of such range and, accordingly, informativeness of different sets of numbers is researched;
• Construction technique of the allowed «corridor» for a Bode diagram of open loop system on conditions of total control error restriction and other techniques of systems synthesis with given accuracy is developed and strictly justified;
• The efficiency of use the suggested models of actions as the total of additive components with restricted different numerical characteristics for each component is justified in the applied problems;
• The analytical method for optimization the nominal values of unstable parameters for a dynamic system with restricted variation range, but with unknown distribution law is designed within the framework of «optimum of a nominal» problem;
• The frequency technique of a maximal error research for a linearized control system designed at actions with restricted derivatives is developed; the importance of maximal error controlling is justified in many applied problems;
• The theoretical backgrounds for frequency synthesis of robust multichannel filters in interests of the conceptual tasks of integration the navigation sensors with incompletely determined properties are designed;
• The set of effective frequency methods requiring no complete spectral-correlation description of actions and permitting to use models, appropriate to an actual volume of a priori information, inserted into the practice of synthesis of filtration and control algorithms.

Research techniques of digital and analog-digital systems

• The research techniques of dynamics and accuracy of analog-digital-analog systems, in particular, closed-loop systems with a continuous unit on an input, digital controller and continuous controlled plant are designed in details;
• The frequency method for solving the direct and inverse problems for investigation the periodic nonstationarity of an error inside the discretization period of analog-digital system, comparison of error averaging outcomes over discrete time and continuous time is created;
• The effective technique to determine the precise expression for frequency transfer function of digital Wiener filter is suggested;
• The original techniques for registration the quantization effects on a level and roundoff at analytical research of microprocessor control systems are designed;
• The method of digital filters synthesis with guaranteed accuracy designed within the framework of the given nonparametric class of signals is developed;
• The methods of robust digital derivation and prediction of signals are suggested and comprehensively designed;
• The method for optimization of multichannel digital filters structure, the part of channels in which is analog-digital (in interests of the conceptual tasks of continuous and discrete sensors integration).

Research techniques and development of onboard operators at motion near to the disturbed sea surface

• The problem of motion control quality near to a rough surface is put and researched as a problem of generalized filtration (space and temporary) at a priori uncertainty having the important appendixes at improving the wing apparatus, ground-effect apparatus and in other conceptual areas;
• The most effective ways for improving the characteristics of transport vehicles of various purposes using the support surface effect, based on implementation of modern and perspective capabilities of traffic control automation means are justified;
• The methods of mathematical simulation of wave disturbances applied to motion control systems and measurement of motion parameters, which are based on research and use of normalized spatial spectra of wave surface and its recalculation with the account of mutual arrangement of vehicle and disturbance velocity vectors are designed and approbated;
• The conclusion about a presence of finite spectral components of wave disturbances on zero frequency for fast vehicle is obtained and justified, the analytical expressions for a level of these spectral components, determining the potential filtration abilities are obtained, the new approach to definition of control errors is suggested according to an indicated factor;
• A series of theoretical outcomes on research of casual processes characteristics formed at suspended summarizing of ordinates or speeds of several diverse points of wave surface or at integration on particular segments of such surface at various modes of relative motion and models of disturbance is obtained, the new experimental and mathematical research techniques for surfaces, representable as a superposition of spatial wave systems are suggested;
• The construction principles and optimization methods for a general structure of the informational-control complex of the vehicle for motion near base surface including an instrumental and algorithmic means of motion parameters measurement, measurement of the support surface inequality characteristics, extrapolation means, synthesizer of an optimal desirable motion trajectory and means for realization this trajectory by combined control principle on disagreement and on disturbances are justified;
• The efficiency of new class of onboard devices on the basis of phase radio altimeters which are capable to ensure high-precision measurements of distances up to several meters (not competing with frequency meters in range up to hundreds meters and pulse meters in kilometer range) is justified from the analysis of possible physical principles of construction the sensors of parameters of low-altitude flight above the sea and parameters of sea disturbance; the experimental samples are created, the patenting is carried out;
• The construction principles of noncontacting meters (not existing before) of sea disturbance parameters and other rough surfaces (current ordinates, slopes, characteristics of a spatial anisotropy, integral characteristics), based on an integration of phase radio altimeters and both inertial means and applicable in motion control systems, in oceanology are justified;
• The synthesis methods of robust integrated meters of motion parameters, optimization of structure and location of onboard sensors, optimization of digital algorithms of integration are developed and approbated;
• The construction principles of algorithmic means for autodetection of general direction of sea waves propagation and other integral characteristics of three-dimensional disturbance under the readings of two or more sensors of waves profile with reference to the optimization problem of transport vehicle motion mode, automation of selection of landing direction and other conceptual problems of motion control are designed;
• The principles and efficiency of adapting the operation algorithms for the informational-control complex to motion modes and to disturbances characteristics: number of seaway, 3D-characteristics and spatial correlation characteristics of support surfaces, to a course and speed of motion;
• The problem of prediction of the collisions of fast marine winged vehicles with conflicting objects, whose complexity is stipulated by a high speed at a low altitude and small radius of operation of onboard radar means is uniformly investigated;
• Comparison of potential efficiency characteristics for various types of sea vehicles with dynamic principles of maintenance is carried out; and the ways of its improving are justified; the areas for the most effective application are determined.

Construction project of the integrated space transport system «Ekranoplane - Aerospace plane»

• The system analysis of creation problem of effective means for delivery the freights and passengers to an earth orbit is carried out;
• The comparative research of the single-stage and two-stage configurations of reusable space vehicles with horizontal and vertical start is executed;
• The analysis and prediction of a world level of key technologies for construction the horizontal launch space systems is carried out;
• The use of perspective capabilities of airplanes and ekranoplanes as the aerospace plane accelerators are compared;
• Capability and efficiency of use the ekranoplane for horizontal marine landing of aerospace plane without a wheel landing gear is investigated;
• The technical requirements to ekranoplane-catamaran with a take-off mass about 2000 ton for start and landing manned aerospace plane with a take-off mass 505 ton are researched, the possibility to apply the existing ekranoplanes for start of light pilotless aerospace plane with useful load of 300 kg is analyzed;
• The aerodynamic configuration of ekranoplane, specially oriented to fulfillment of accelerator function and landing platform for a perspective space airplane is suggested and optimized on the basis of research of screen effect fundamental legitimacies;
• The structures of control systems for absolute and relative motion of transport system units «Ekranoplane - aerospace plane» are synthesized, the potential characteristics of its accuracy and reliability are analyzed;
• The kinematic motion schemes of ekranoplane and space airplane in modes of preparation to start and start of aerospace plane designed and the means of their implementation are justified;
• The structure of the automatic docking assembly for reception the space airplane on ekranoplane in a landing mode with local systems of automatic positioning of docking mechanism, processing the residual errors of a control system by relative motion is designed;
• The possible principles of organization and financing, terms of implementation and measure of effectiveness of the international technological project of creation the transport system «Ekranoplane - Aerospace plane» are analyzed, its first stage - investment project «Fitting-out and world presentation of Russian 400 ton ekranoplane, supported by the Department of Defense and Department of Economic Affairs of Russian Federation under the decree 1371/31-442 from 4.06.99 is justified».

Development of onboard system for measurement, control and record of motion parameters of vehicle at motion close or on the rough support surface

The system contains three phase radio altimeters with accuracy ~5 cm, GPS-receiver, inertial and other sensors, hardware and software for digital data processing, advanced interface. The system is most effective at testing the experimental vehicles, because it allows to control and to record simultaneously to the hard drive the parameters of support surface irregularities and parameters of appropriate perturbed motion of the vehicle.

Theory and software for simulation and stabilization of vehicles with flexible structure

The application package allows to research the legitimacies of derivation and oscillations property of configuration elements of vehicles, and also the influence of such oscillations on ability to keep the required motion trajectory and functional characteristics of the vehicle.

Software development for design automation and simulation of onboard systems for obtaining, processing information and control for perspective automobiles

The experimental applied software package allows to optimize a structure and sensors location points on the automobile, structure of information distribution system, obtained from sensors, on all devices-customers of the distributed computer network of the automobile and data file controlling, onboard wiring lines, printed wiring schemes, distributive chocks, safety devices for electric circuits, scheme and algorithms of automated technical diagnostics. It also allows to organize asynchronous action of digital sensors and customers of the current information, to automize the structural design of the database with support of the multibus architecture of automobile digital control system and embedded software.