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Interfaces for Multivariable Control Systems


Graphical User Interfaces for Computer-Aided Analysis and Design of Linear and Nonlinear Multivariable Control Systems

Tech Area / Field

  • MAN-COM/CAD and CAM/Manufacturing Technology
  • INF-SOF/Software/Information and Communications
  • MAN-MPS/Manufacturing, Planning, Processing and Control/Manufacturing Technology
  • SAT-AER/Aeronautics/Space, Aircraft and Surface Transportation

3 Approved without Funding

Registration date

Leading Institute
National Polytechnical University of Armenia, Armenia, Yerevan

Supporting institutes

  • Closed Joint-Stock Company "Infokom-Alpha", Armenia, Yerevan


  • Controllab Products B.V., The Netherlands, Enschede\nCaledonian University, UK, Glasgow\nUS Military Academy, USA, NY, West Point\nMSC. Software GmbH, France, Palaiseau\nUniversity of Calgary, Canada, AB, Calgary\nVisual Solutions, Inc., USA, MA, Westford\nThe Advanced Control Technology Club, UK, Glasgow\nUniversity of Strathclyde / Indistrial Control Center, UK, Glasgow\nNiconet International Society, Belgium, Leuven\nCleveland State University / Fenn College of Engineering, USA, OH, Cleveland\nSENER Ingenieria y Sistemas, Spain, Madrid

Project summary

The problem of Computer-Aided Control System Design (CACSD) is one of the central problems in modern control theory and engineering.

The recognized world leaders in that area are such renowned corporations and firms as The MathWorks, Inc. (the creator of the well-known language for scientific and technical computing MATLAB), The Wolfram Research, Inc. (whose package Mathematica is used in NASA), EASY5 Product (The Сompany Boeing) and some others.

At present, in spite of an evident progress in the methods of CACSD, numerous important applied problems are too far from being solved with the help of these methods. The fact is that most of the real feedback control systems belong to a class of complex multiple-input multiple-output (MIMO) (or multivariable) control systems with interconnected separate channels. Further, the real MIMO systems, like any other control systems, always have in their structure some nonlinear elements, the presence of which may essentially affect the dynamical characteristics of the system and even bring it to failure.

However, the application of the well-known Graphical User Interfaces (GUIs) in the CACSD domain is confined mainly to linear single-input single-output (SISO) control systems (The SISO Design Tool (The MathWorks, Inc.), The Control System Professional (The Wolfram Research, Inc.), Analysis & Simulation Toolkit (EASY5 Product), VisSim (Visual Solutions, Inc.), etc.).

Certain progress in evolving the CACSD tools to linear multivariable systems relates to the methods of robust control theory (for example, The Robust Control и -Analysis and Synthesis Toolboxes in MATLAB). But these methods actually don’t allow to take into consideration such extremely important structural features of the MIMO control systems as uniformity, symmetry, anti-symmetry, etc. That circumstance considerably narrows the application limits of the mentioned methods and reduces the efficiency of the synthesized with their help controllers.

As concerns the means of analytical investigation of nonlinear MIMO control systems, in the advanced packages on CACSD those tasks practically are not touched upon, even for SISO case (in The Nonlinear Control Design Blockset in MATLAB it is supposed beforehand that the initial SISO nonlinear system has already been designed and has no self-oscillations). That situation is due to the fact that nowadays the theory of nonlinear MIMO control systems is not evolved to a sufficient extent and is rather far from many real needs of practice, though the problems of computer modeling of nonlinear MIMO systems are substantially solved in such packages as SIMULINK (MATLAB), Analysis & Simulation Toolkit (EASY5 Product) and others.

In the Project it is planned the development of having no analogues a basic and two specialized GUIs. The basic GUI The MIMO System Design Tool is destined for analysis and design, on the basis of frequency and root methods, of linear and nonlinear MIMO control systems of the main structural types described in technical literature. The specialized GUIs are intended for the following engineering fields (in the brackets are given the GUIs’ names):

1. Multivariable Uniform Process Control with PID Regulators (The MIMO PID Regulator Design Tool).

2. Control Systems for Two-axis and Three-axis Gyro-Stabilized Platforms (The Gyro-Stabilized Platform Design Tool).

In the basic GUI The MIMO System Design Tool it is necessary to emphasize the following expected results, having important scientific and applied significance, which are practically absent in the CACSD packages of the world leading firms:

1. Computing methods and techniques of analysis of one-frequency self-oscillations in nonlinear MIMO systems (on the base of describing function method).
2. Computing methods and procedures of analysis of nonlinear MIMO systems’ absolute stability (on the base of V.M.Popov criterion, circular criteria, etc.).
3. Multidimensional root loci building procedures for linear MIMO systems of the main structural types (uniform, symmetrical, anti-symmetrical, etc.).
4. Interactive procedures and techniques of choosing the correction in linear MIMO systems, on the base of the main frequency and root methods known from classical control theory (Bode, Nyquist, Nichols, Evans, etc.).

The GUI The MIMO PID Regulator Design Tool is destined for tuning the parameters of PID (Proportional, Integral, Derivative) regulators, which are widely used for controlling the MIMO uniform (that is having identical transfer functions of the separate channels and static cross-connections) Process Control. As examples of such Process Control, one can give the control systems of tuyure-blast distribution in blast-furnaces, technological processes in chemical and steel industry, power and thermal systems, and many others.

In the GUI MIMO PID Regulator Design Tool one can point out the underwritten important results:

1. New theoretical methods and computing algorithms, based on frequency and root domain approaches, destined for design and analysis of uniform Process Control with PID regulators.
2. Systematization of the most wide-spread in practice uniform interconnected Process Control.
3. Mathematical and graphical libraries for typical structural schemes of Process Control.

Also to a class of MIMO systems belong and control systems of gyro-stabilized platforms (The Gyro-Stabilized Platform Design Tool), very wide-spread in cosmonautics, aviation, ship-building, etc., where they are used for solving the tasks of attitude control and navigation. In these systems there are dynamical and are not excluded also kinematical cross-connections among the stabilization channels caused by the gyroscopic properties of servo and/or sensitive elements.

The significant expected results in the GUI The Gyro-Stabilized Platform Design Tool are:

1. Frequency and root domain design methods and respective computational algorithms, which will take into consideration the primary dynamical and kinematical properties of conventional gyro-stabilized platforms.
2. Mathematical and graphical libraries of structural schemes for two-axis and three-axis gyro-stabilized platforms’ control systems.
3. Mathematical libraries of nonlinear and linearized models for the main types of gyroscopic devices.

A distinctive and important feature of the planned GUIs is that all the design procedures will be, regardless of the MIMO system order and the strength of cross-couplings, quite analogous to traditional procedures used in SISO control engineering.

In the specialized GUIs the corresponding control objects (plants) will be considered as multivariable, without any assumptions of negligibility or absence of the interconnections. Such problem statements are not enough presented in the well-known packages on CACSD, what appreciably increases the practical significance, efficiency and commercial value of the GUIs.

The basic GUI The MIMO System Design Tool may find a wide application at institutions and firms, which are engaged in development and manufacture of complex MIMO control systems in various branches of industry and engineering. Besides, it may be used at universities, technical colleges, etc., as a visual and flexible tool presenting the fundamentals of classical and, within the scope of frequency and root methods, modern control theory. The specialized GUIs also may be used, besides the corresponding branches of engineering, when teaching special technical disciplines at educational institutions.

The united theoretical basis of the GUIs is the well-known in multivariable control theory Gain Locus Method proposed by the world renowned British control theorist A.G.MacFarlane, and evolved essentially in the works of O.N.Gasparyan towards engineering applications. That method, connecting, on the base of linear algebraic operators theory, with the initial linear MIMO system of the N-th order a variety of N independent fictitious SISO systems, forms natural and exceptional conditions for extending to multidimensional case all the primary results of linear and nonlinear SISO classical theory. In fact, the distinctive feature of the proposed GUIs will consist in a rigorous replacement of the given linear or linearized MIMO system investigation task by a task of investigation of a certain “equivalent” fictitious SISO system with, in general case, complex parameters.

When developing the basic GUI The MIMO System Design Tool it will be used, in addition to the Gain Locus Method, the methods of computing mathematics, functional analysis, general theory of linear and nonlinear control systems, and robust control theory. Besides, it will be used revised and modernized computing algorithms from the developed by O.N.Gasparyan GUI for linear MIMO systems, the potentialities of which, as a multidimensional control system frequency and root domain design tool, exceed to a certain extent the potentialities of such packages as The Control System Toolbox (The MathWorks, Inc.), The Control System Professional (the Wolfram Research, Inc.), and of many other similar packages.

When designing the specialized GUIs, it will be used the results of research in the corresponding fields of science and technology carried out by the Project participants.

It is planned participation in the Project of 3 Doctors of Engineering Sciences, 6 Candidates of Engineering Sciences, and 14 highly-qualified specialists having more than 15 years experience in the related fields. On the considered topics the Project participants have published more than 160 scientific papers.

The proposed Project completely responds to the primary ISTC objective – to provide to weapons scientists and engineers the opportunity for peaceful scientific and research activity.


The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.


ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.

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