Systems
analysis of space industry and motion control Ïf complex
mechanical systems A.P.Alpatov, P.P.Byelonozko Institute of Technical Mechanics of
National Academy of Science of Ukraine and National Space Agency of Ukraine The establishment of the Institute of Technical
Mechanics (ITM) of National Academy of Science of Ukraine (NASU) and National
Space Agency of Ukraine (NSA) is related to Academician M.K.Yangel. In April
1966, on Academician M.K.Yangel's initiative a new academic research unit was
created - the Sector of Engineering Mechanics Problems within the
Dnipropetrovsk Branch of the In 1980, on
the basis of the Dnipropetrovsk Division was created the Institute of Technical
Mechanics of NASU, headed by NASU academician Victor V.Pilipenko. In 1980, the
Institute of Technical Mechanics of NASU, headed by NASU academician Victor V.Pilipenko,
was created on the basis of the Dnipropetrovsk Division. Scientific
directions of the Sector's activities were inherited respectively by the
Dnipropetrovsk Division of the Nowadays,
there are 14 scientific departments in the Institute of Technical Mechanics of
National Academy of Science of In 2000, on
the basis of Control Mechanical Systems Department through uniting with Systems
Analysis Department, the Department of Systems Analysis and Control Problems of
ITM NASU NSAU (hereinafter referred as the Department) was established. The basis of
systems analysis of space industry problems has become one of the scientific
activity fields of ITM NASU NSAU. This was initiated by V.S.Budnik who
contributed his rich industrial experience and knowledge to the development and
improvement of scientific basis for rocket and space systems optimal design. During the
past years, the main customers to enjoy the Department's research and
scientific developments were National Academy of Science of The basic developments
of the Department are directed to solve the problems in the Ukrainian rocket
and space industry. They have the background of the fundamental investigations
that are carried out in accordance with the research plan of NASU. The results
of the fundamental investigations are used as scientific and methodological
support for the rocket and space engineering. The methodological developments
are also employed to assess the efficiency of the national space program
projects and to produce a wide range of analytical materials for the state
authorities. The topical analysis of the Department's investigations and developments
are given in. One can find a carefully prepared list of the monographs and
scientific articles there and the main research results are shown. Now we pass
over to the brief review of the main scientific results during the last years
and more detailed description of some researches in the sphere of dynamics and
motion control of the complex mechanical systems. Systems analysis of
Space industry problems The past years are remarkable for the
Department due to its investigations of the space systems. On the basis of the
systems approach, the general methodology, mathematical models and assessment
methodologies of competitive space transportation systems are developed.
Hierarchical multicriterion approach to analyze the efficiency of space systems
projects for various purposes is elaborated. The analytic and information
support of the investigations is invented. The Department has carried out the
systems analysis of space systems development - satellite systems and
transportation systems. The main world tendencies are determined. The proposals
on the promising branches of development for Ukrainian space transportation
systems are formulated. The method of regressive systems analysis to carry out
the regressive modeling of non-structural objects of various natures with
regard to their operation data is developed and investigated. On the basis of systems investigations, ITM
NASU NSAU has performed the development of and carried out scientific and
technical support of 2002- 2007 Ukrainian State (National) Space Program and
developed the 4th Scientific and Technical Ukrainian State Special Space
Program for the period of 2008- 2012. While performing the systems analysis of the
4th Ukrainian State Space Program, the following priorities were taken into
account: -
development
of a Ukrainian spacecraft group to work on the regular basis for performing the
Earth observations and geophysical monitoring "Sich"; provide its operation and
exploitation; -
development
of National System of Geoinformational support as a part of European system
"GMES" and universal system "GEOSS"; -
improvements
of the system of space-time and navigation support for -
creation
of the conditions for the commercial use of the Ukrainian space launchers
within the projects of "Cyclone- -
creation
of the satellite telecommunications net of general use and special
telecommunications networks applying the National satellite connection; -
manufacture
of space launchers "Zenit", "Cyclone" and "Dnepr"; development of promising
rocket-space complexes and spacecrafts of a new generation; -
space
investigations in the spheres of solar-geo connections, astrophysics, cosmic
biology and material science particularly in the framework of the international
projects "Spectr-P", "International Space Station", "EXPLORATION" and " The Department also carried out the
investigations related to the problem of the space debris. Nowadays, the
problems of prevention of near-Earth space environment from pollution and
flight safety problems are becoming more and more acute. The two aspects of
protection -safety of space flight operation for space technology objects
against the meeting with the space debris fragments and protection of these
objects to sustain their working conditions after meeting with the space debris
fragments - are considered. Apart from the above
mentioned issues, the development of methods and measures to prevent the
pollution of near-Earth space environment during the service life period of
space launchers and spacecrafts as well as during their out-of-service period
is also very important now. The complex of problems related to the
necessity to de-orbit the rocket and space technology objects from their
operational orbits when they ceased to function is investigated. The main
issues of specifications to prevent the pollution of near-Earth space and
enhance the safety of space flights are developed. These issues are harmonized
with the corresponding international documents. Research of free and controlled regimes of large transformable mechanical
space- and ground-based systems operation under a wide range of effects The dynamics of spatially developed mechanical
systems is to be singled out as a separate branch of dynamics of rigid bodies
and deformable bodies. It is natural and obvious that 0spatially developed
transformable mechanical systems are large space structures. The name of "large space structures" is widely
used to describe the space systems possessing the following properties: -
large
geometry (in comparison with the conventional spacecrafts); -
necessity
of on-position deployment after placing into the orbit (due to the transport
limits on payload dimensions); -
low
rigidity (due to the transport limits on payload weight); -
low
frequency of natural oscillations (commensurable with controlled motion
spacecraft frequencies); low values of interval damping factor. Design, development and operation of large
space constructions are compounded with a number of difficulties: -
necessity
to develop transformable constructions, which are in fact self-reacting devices
in case of automatic deployment in space; -
difficulties
with the imitation of orbital conditions including zero-gravity conditions and
thermal conditions at ground-based experimental work; -
control
problems with orientation and configuration especially with damping of elastic
vibrations and shaping of the reflecting surfaces; -
specific
character of mathematical simulation of dynamics especially for large objects
and necessity to identify the parameters. Many scientific works published as
long as in 80-s ‑ 90-s are devoted to theoretical and experimental
investigations of large space structures. But the above-mentioned problems
connected with dynamics modeling conducting of ground- and space-based
experiments and the further development of control systems are still urgent
problems. In spite of the complicated technical side and
high costs of large space structures, it may be cited a sequence of current
evidences of reliable and economically efficient systems which have been
performed practically. That is the important step forward for rocket and space
engineering. The following classification is not complete
but singles out the most wide-spread types of large space structures: -
large
reflecting surfaces (satellite-communication antenna, space radio telescope,
solar concentrators, plane reflectors); -
framework
constructions for various applications; -
space
manipulators (multiple-link mechanisms); -
tethered
space systems. From the standpoint of dynamics
modeling, geometry does not have any special bearings on the existing
formalities, but it greatly influences the complex character of an object
design, opportunities to simplify a complex object, and the number of necessary
computation operations. Therefore, modeling of large mechanical systems is not
mathematically quite different from those of small geometry. However, the
problems to choose the method for equation development and rational choice for
simplifying assumptions are still urgent, despite the rapid development of the
computer tools. The commonest simplifying assumptions applied
to choose the mechanical design models for a large mechanical system may be
singled out as follows: -
the
body may be substituted with the particle; -
the
body mass is not considered but those geometric parameters and mechanical
properties which are important for system's proper work are taken into account.
In this case the body is substituted with the constraint; -
the
relativity of the bodies' travel is disregarded; that allows us to consider
several bodies as one; -
the
relativity of the travel of the body's particles is not taken into account; due
to this a deformable body is substituted as non-deformable. The dynamics study of complex
mechanical systems to solve the technical problems on the base of mathematical
model collections of various detail levels has proved to be an efficient
method. The results of the Department's investigation of space manipulator
controlled motion evidence this fact. The investigations were initiated in the
80-s as planned scientific and research investigations and this activity has
been further developed to conclude the contract with Central Research and
Development Institute for Robotics and Technical Cybernetics for designing a
manipulator for "Buran" transport spacecraft, ordered by Rocket and Space
Complex "Energy". Hierarchical collection of dynamic models
developed to be applied for 6-link hand-like mechanism of manipulator under
research may be generalized as follows: -
model
of system of two bodies connected with each other by joint bearing, made up by
rigid mass-free rods and joints; this model is intended for dynamics
interaction investigation of the carried by manipulator payloads and the
spacecraft, determination of controlled torques for the desired trajectories of
payload manipulations, synthesis of control algorithms and designed trajectories; -
the
dynamics model of manipulator with rigid mass links working on the movable base;
the model is to investigate the dynamics of unloaded manipulator or low loaded
manipulator; -
the
above-mentioned models with consideration of the rigidity of rods, connecting
flanges, and gearings in joints; they are to assess the accurateness of
manipulating at typical manipulation regimes of loads placing into, or removal
of transport section; -
the
above-mentioned models with consideration of rigid rods mass; they are intended
to determine the system natural frequency, to study the motion stability of
both the loaded manipulator and the unloaded one, to carry out the testing
analysis; The developed models have been
applied for manipulator control algorithms synthesis as well as for selection
of desired trajectories for payloads motion. The recommendations due to the
results of construction units elasticity analysis have become the base for the
further elaboration of the manipulator of the mechanism under construction. In order to develop the control systems over
the spatial position and configuration of large mechanical systems, there
appears the necessity to employ a great number of drive devices, range-finding
and orientation sensors which are included in the control of the each body. At
conventional control system, each control channel possesses its own transducer
and all the channels have to work simultaneously while at large mechanical
systems operation this solution is not reasonable because this measuring system
turns to be too complex and possesses a big total mass. The fact that the
energy source should be of great power to ensure the simultaneous work of many
drives adds to this problem. Movable control is to be regarded as one of the
solution opportunities of the above-mentioned conventional approach problems.
One or several channels are under simultaneous control at the movable control
regime. This allows the mass reduction of the measuring system, to make its
construction less complex as well as decrease the total power of the feeding
system. The results of original investigation on the development of movable
control systems over various mechanical systems including large mechanical ones
are generalized in the monograph. Large space transformable reflectors are a promising
branch of the space complex mechanical systems which refer to the large space
structures. Within the framework with the Institute of
Space Constructions, established in Georgia in 1980-s for development of space-
and ground-based deployed antennas with a large reflector diameter (up to The complex of
investigations of the shape-forming processes for the large space reflector of
cable-stayed design is carried out (developed in the The Department has also performed a large
number of investigations on dynamics of tethered space systems, a promising
branch of large transformable systems. The optimization of space launcher
controlled motion is studied. Much attention is given to the identification
problems of the systems beyond the structure classification. The Department's experience gained in the
rocket and space engineering field is also utilized in interdisciplinary
spheres. Studies of medical informational systems, intelligent modules and hardware
for biomechanical human monitoring Biomechanical studies are
directed to create hardware and intelligent module for medical diagnostics and
correction of functional state of human locomotor system. It is proved that
under pathology conditions the human locomotor behaves as a single system where
the problems with peripheral units of locomotorium (conditionally - object of
control) are insepa-rable with those of central nervous system (conditionally -
system of control). The methodo-logical integrity of pathology research of
locomotorium and central nervous system by means of informational-analytical
support allowed deeper understanding of mechanisms of locomotorium adaptive
self-reacting under pathology conditions and conditions of rehabilitation after
trauma and diseases. It is evidenced that biomechanical analysis of human macro
motions is adequate and effective control technology over rehabilitation of
both patients and disadvantaged people suffering from locomotorium pathology.
Micro motion analysis has proved to be the most accurate and effective
technology to control rehabilitation of neurotic patients. Based on biomechanical models methodical
principles for program and technical complexes design are developed. They are
applied for diagnostics, treatment and rehabilitation of human locomotorium.
The conception of multipurpose bank of knowledge for scientific research
support, education and practice in the medical sphere is proposed. The developed program and technical complexes
have undergone the many-year approbation in the leading health care
institutions of Dnipropetrovsk region and have been approved for their
efficiency. The research results are being implemented into the experimental and
practical medicine. All the scientific branches of the
Department are developing intensively, paying attention to the promising
tendencies and modern requirements of science and technology. For example, the
researches on method development for equivalent finite-dimensional
representations of extended spring units design models are currently carried
out. These units belong to the mechanical systems with the enhanced
requirements to the equivalency, considering the dynamics interaction of the
unit with the jointed bodies. The Department possesses the remarkable
scientific staff. The number of scientific workers, engineers, and technicians
who participate in the scientific investigations totals 40. There are 3 Doctors
of Sciences (the second academic degree) and 10 Candidates of Sciences (the
first academic degree, comparable with PhD degree) among them. The research and
methodological base of the Department includes the laboratory equipment for
tethered space systems units investigation, biomechanical stands, measuring
plants, and program complexes to assist in problem solutions in the main
investigation fields. The specialists of the Department are able to solve
efficiently the fundamental problems as well as applied ones to encourage the
development of various branches of rocket and space engineering. |
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