Сайт Информационных Технологий

Gugushvili A.Sh., Kvertskhishvili D.T., Mamukelashvili I.O.

Georgia, Tbilisi, Georgian Technical University, alik@gtu.edu.ge

METHODS OF MULTIMEDIA FOR STUDYING THE THEORIES OF AUTOMATIC CONTROL

Abstract: Multimedia is already widely used in Georgia and its use well increases in future. Now days there are new possibilities to represent the teaching process better. Multimedia approach used for studying the course "Theory of Automatic Control". It must contain the projecting of pedagogical conception and to bring it to the appropriate model of the material, which we have already realized. To interfere in the process of creating the model which is still the fault of our packet.

Multimedia is implanting in various fields, by means of which is almost impossible to differ the model created for computer model from real. It creates great perspectives in projecting, design, medicine science and educational systems. The status creation of computer arrangements is directed to that the students who use it analyze and acquire it. Yet from the motor of creating computer it was an idea to use its program of computer providence in the teaching process.

The use of computer potency in education is developing quickly and promises the increasing of the quality of studying process.

Multimedia is already widely used in Georgia and its use well increase in future. The knowledge that provides the preparation of skilled specialists is due to quick change. The level development level nowadays especially in techniques requires systematic refreshments and that's why the teaching must effective, quick and mobile.

The researches proved the successful teaching by means of computers. It can mentioned that in the process of working of iteractive program the attention is doubled, the economy of time spent on the studying of concrete questions is 30%, and the acquired knowledge will be mentioned for a long time.

To make a model of any object is very difficult that is connected with great material problems. That's why the problem of the objects visualize is possible to solve by means of computer. It's much easier in this case it's possible to make some changes in model, to observe the heavier of the object in various conditions and so on. The products of Multimedia existed nowadays can cardinal change the instruments developed for graphic works for the last 5 years to work with the multimedia products of high quality is much easier and quicker than with other materials.

Now days there are new possibilities to represent the teaching process better. A student can study theoretical material and conduct laboratory experiments without changing place. When we project the Multimedia model it must be taken info the consideration both pedagogical side the modernization of multimedia methods can give the possibility of using with potentials of traditional teaching process. Teaching methods must be near to adapted teaching ways and style. Teaching by this way can be conceptual and profound. A customer sees visually all the models of product, by which he (she) can learn understand the definite side that interests him (her). As for profound teaching it contains more actual materials of teaching. It relies upon the theories, examples, and demonstrative parts. It contains multimedia technologies with animation, visualization and other. Multimedia approach used for studying the course "Theory of Automatic Control".

For this reason are made multimedia packets:

1. The theory of automatic control;

2. The theory of optimal control;

The Questions of stability are examined on the example of centrifugal regulator of Watt. There are examined as the classical criterions of stability as the fractional method of learning stability.

Let's briefly dwell on some theoretical results.

In modem technology thank to abundance of automatic control instruments the theory of automatic regulation is of great importance. One of the important questions, came up to automatic regulator designer, is a question about the stability work of the system machine- regulator. This question in many cases can be solved on the basis of the theory of Lapunov.

The most existence system of automatic regulation is the system of a steam machine- centrifugal regulator of Watt.

Centrifugal regulator is a vertical bar, mighty to revolve around its vertical base, on the top of which on the hinges are fasten two identical loads at the ends. The bars and; are fasten with the additional hinges, so that to move aside they are able only simultaneously on the same comer , being in the same vertical plane, fastened motionless with the bar.

When the bars and move aside of their vertical position on the comer , they with help of hinges set in motion the special muff, put on the bar, so that the distance of this muff up to the top of the bar is in proportion with . The length of the vertical bars and lets set to 1 and the weight of each loads, fastened on its ands, mark with . If the bar is revolving with the comer speed , and the bars and are moved aside from the vertical position on the corner then on each loads effects the centrifugal power

(1)

In the same time on each loads effects gravity, equal to

(2)

Simplification explanation of the work of centrifugal regulator consists in that, that in given comer speed the bars and move aside under the effect of power (1) and (2) on the comer determined from the equality (Fig. 1)

(3)

From the correlation (3) comer is formed as a single-valued monotonous increased function of the speed .

We'll consider that the power of friction is proportional of the speed. Movement of the weight and has a mark, opposite of this speed, or it has a size -,

were is permanent, so if set to coordinate, determining the position of weight , we'll get for differential equation

A steam machine is a flywheel with a moment inertia J, in revolving movement by the power of steam and capable of doing useful work.

Differential equation of the steam machine can be written in this way , where w is a corner speed of revolving of a flywheel, is a moment of the power of a steam action. is a moment of the power influence on a flywheel gravity cage. The moment of the power influence on the steam , is depended on that how much the lid is open, which is giving the steam to the cylinders of a steam machine and the moment is depended on a chargement of cage.

Centrifugal regulator connect steam machine in order to support the balance if its motion. It measures revolving speed of the flywheel and if it is too high decreases giving the steam, and if it is too low increases giving the steam. For the realization it measures revolving speed of the flywheel and if it is too high decreases giving the steam, and if it is too low increases giving the steam. For the realization of this purpose the flywheel of the steam machine is tied with the help of the gear with the vertical bar of regulator (Fig. 1), so that between the comer speeds and arises permanent communication, where n is so-called transmission number. Such is the influence of the machine on the regulator, in result of which measuring the speed of the flywheel revolving is realized. On the other hand the muff of the regulator is connected with the lid, giving the steam so that

(4)

where is a some kind of middle meaning of , near of which must be supported the meaning of the regulatory quantity of is a meaning of the power of steam influence at , and is a permanent coefficient of proportionality.

Linear equation system of the machine-regulator has the form

(5)

Characteristic polynomial obtained with linear system for

(6)

Coefficient of this polynomial can be as a positive as well a complex.

On the occasion of the positive coefficient condition of stability has the form of ,

where

(7)

is called irregularity motion of the steam machine.

From the formula (7) the following conclusions were done:

1. Increasing the weight of m balls has an injurious effect on stability.

2. Decreasing the coefficient of friction has an injurious effect of stability.

3. Decreasing the moments of inertia of the v flywheel has an injurious affect on stability.

4. Decreasing the irregularity v has an injurious effect on stability.

In the case of complex coefficients the equation (6) gives a chance to built a lot of Mandelbrots. The black color points the stable spheres. The more we move from the black color the more the system became unstable.

The system machine-regulator was modeled in the animated packet "3D studio max R3".

Changing the parameters the corresponding animated models are obtained, which repeat all qualities of real technical apparatus. The attained animation has the sound characteristic for these systems and also has corresponding theoretical commentaries.

For analyzing the stability with the methods of fractional theories in Pascal language corresponding program is written.

Later on a unification of separate parts of multimedia packet takes place. This takes place in the form of encyclopaedia and the program Viewer Project Editor is collecting them.

The second packet of multimedia concepts the usage of multimedia methods and the theoretical and practical study of one of the main method-maximum principles the optimal operation. The structure is selected so that its possible an independent study of different parts. A student can realize well the main principles of optimal operation and get to know landing on the moon softly. This task is the task of optimal operation, we review here the task of extremal operation. Its calculation is rather long that's why speaking of the result at first. The extremal operation must provide the following conditions:

This operation is equals 0 at the beginning interval but at the last interval is equal . It represents the only extremal operation. It must be appalled by the following condition.

There if it's possible to sit softly then there exists operation that gives us right to carry out it with the minimal expense of fuel. This operation must be extremal. It must have u(t) face. Here we try to represent the family of phase trajectories appropriate to u(t) operations.

The soft landing on the moon:

The first condition:

The functional has face:

Now we are getting to the expriment and make an animate picture for one of the variants of program. That is quite easy to use and effective. This file is done "3 Studio max R3" and assembling program this packet is WEBEZPRES,

To our opinion the process of creating multimedia packet must be divided into two parts. 1. It must contain the projecting of pedagogical conception and to bring it to the appropriate model of the material, which we have already realized. 2. To interfere in the process of creating the model which is still the fault of our packet. It's projected the ways of its imorovement.


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