#1(26), 2007



Dynamic investigation of a spherical four-link slot-and-crank mechanism with clearances in kinematic pairs. N. Davitashvili, G. Sharashenidze, D. Balakhadze. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 7-18, (Engl.).

In this paper, the dynamic investigation of a spherical four-link slot-and-crank mechanism with two clearances in rotary and translational kinematic pairs is given. On the first stage of the investigation there are determined all kinematic parameters of an ideal spherical slider-crank mechanism. Further, it is found kinetic energy of the mechanism with clearances, by which it is obtained the systems of differential equations of all forms of complementary and basic motions of a spherical four-link slot-and-crank mechanism. The received results facilitate to conduct comparative analysis between results of ideal and real mechanisms and to investigate the  mechanism by taking into account clearances in kinematic pairs. 3 ill. Bibl. 12. Engl., summ. in Russ.


Influence of Transients in Electric Motors on the Stability of Robotic Systems. K. Zimmermann, I. Zeidis, Yu. Martynenko, A. Sñhneider. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 19-31, (Engl.).

 The stability of the mobile robot – tool system, with the time delay by using an example of drilling is analyzed. This study based on the analytical electromechanics, which involves Lagrange – Maxwell equations that enable one to take into account the transients in the electric actuator within the framework of a self-consistent dynamic model. It is shown that the time delay in the control loop influences the system’s stability. The results of the calculations agree with the results of experiments. 7 ill. Bibl. 6. Engl., summ. in Russ.


The Optimization of a Novel Prismatic Drive. D. Chablat, S. Caro, É. Bouyer. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 32-42, (Engl.).

The design of a mechanical transmission taking into account the transmitted forces is reported in this paper. This transmission is based on Slide-o-Cam, a cam mechanism with multiple rollers mounted on a common translating follower. The design of Slide-o-Cam, a transmission intended to produce a sliding motion from a turning drive, or vice versa, was reported elsewhere. This transmission provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. The pressure angle is a relevant performance index for this transmission because it determines the amount of force transmitted to the load vs. that transmitted to the machine frame. To assess the transmission capability of the mechanism, the Hertz formula is introduced to calculate the stresses on the rollers and on the cams. The final transmission is intended to replace the current ball-screws in the Orthoglide, a three-DOF parallel robot for the production of translational motions, currently under development for machining applications at École Centrale de Nantes. 12 ill. Bibl. 11. Engl., summ. in Russ.


Non-spherical joint for five-side machining by Octapod. D. Sula­manidze, M. Valasek, V. Bauma. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 43-48, (Engl.).

 The problem of developing of new joints with increased mobility is the topic of this paper. It was motivated by the good properties of redundant parallel structures, mainly by the possibility of five-side machining combined with high stiffness and low total mass of moving parts of such structures. The practical contribution of this research is the overcoming of the joints’ restricted mobility, one of the most considerable obstacles that prevent more common application of parallel and redundant parallel kinematic structures in practice. The main goal of the authors was to achieve an increase of the working space of parallel kinematic structures by improving the mobility of the joints. For this purpose new method was developed. This method is based on the application of non-spherical joint with increased mobility reaching 270. The joint was tested to determine its usability for five-side machining in combination with redundantly actuated kinematic structure Octapod. The inverse problem was solved and the required angles were defined. The results of these calculations showed that new non-spherical joint can fully serve for five-machining. 6 ill. Bibl. 7. Engl., summ. in Russ.


VIBROISOLATION OF MECHANICAL OSCILLATION SYSTEMS. M. Chelidze, M. Tedoshvili, H. Tsulaia. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 49-52, (Engl.).

The article covers issues concerning vibro-isolation of mechanical systems with use of  pneumatic insulators of new design. The springy amortization and damping of mechanical oscillatory systems are realized in one closed space of shock absorber. The constructions enable effectively extinguish the amplitudes of  fluctuations and noise of the oscillatory object in broad range of frequencies.  5 ill. Bibl. 4. Engl., summ. in Russ.


The theory of soil-unpacking technological process with the use of gas-dynamical effect. R.M. Makharoblidze, Z.K. Makharoblidze. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 53-69, (Russ.).

The search of resource-saving technologies of soil cultivation and unpacking, and also of development of mountainous agricultural arable lands, with the help of moisture delaing on the slopes, leads us to the use of gas-dynamical effect. Elaboration of the theory of interaction of compressed air and soil environment, with the purpose of substantiation of basic parameters of the technological process and working organ, should favour a creation of the resource-saving technology and technical means for soil cultivation. An attempt is made in the article, to use with that end in view, the achievements and methods of the theory of explosion in deformable environment. The functional dependences of the initial power and depth of feeding of the compressed air, upon the degree of crush, radius and volume of destruction of the packed soil, are established in the form of analytical calculating formulas. For making more exact the stated theory, a practical example of use of the theoretical results and trends of subsequent researches is given. 6 ill. Bibl 7. Russ.



ROUGH METHOD OF THE PREDICTION OF STABILITY INFRINGEMENTS OF THE HIGH-SPEED MODE OF A TRANSPORT DIESEL ENGINE. A. Muchaidze, Kh. Mgebrishvili. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 70-73, (Russ.).

Possible infringements of uniformity of work of a multicylinder transport diesel engine which can promote occurrence of the compelled fluctuations and the resonant phenomena of an operating conditions are considered. The developed simplified method allows to expect beforehand these oscillatory processes and to warn them. Bibl. 3. Russ.


About drawing up of the mathematical model of spatial movement of the three-mass oscillatory system – analogue of the vibratory technological machine. V. Zviadauri. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 74-80, (Russ.).

The technique of drawing up of mathematical model of spatial movement of three-mass oscillatory system - analogue of the vibrating technological machine is presented. The differential equations are nonlinear interconnected and with their help it is possible to operate the technological process depending on dynamic and kinematic parameters of all system. 2 ill. Bibl. 4. Russ.


formATION Particularities of surface layers of a tool from carbon-free alloys at natural thermo-mechanical working in the cutting process. A. Sahradyan, S. Mamyan. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 81-86, (Russ.).

It is investigated an increase in the physic-mechanical properties of surface contact layers of the tool from carbon-free alloys with intermetallide strengthening of brands B11M7K23, B14M7K25 according to the developed technology of natural self-organizing low-temperature thermo-mechanical treatment (NSLTT) at cutting of steel 45. The advantage of developed technology consists in the fact that practically without using additional equipment, devices and energy, by control and regulation of parameters of the process of cutting it is achieved a change in the structure of thin contact layers on the front surface as a result of deformation-temperature action. In this case a fine-grained structure with developed substructure and increased dispersiveness of strengthened phases is formed; it is increased micro hardness, thermal stability, wear resistance, service life and operating characteristics of the tool. 3 ill. Bibl. 5. Russ.


THE METHOD OF ORGANIZATION OF EXPRESS BUS RUNS ON LONG-DISTANCE ROUTES. O. Gelashvili, N. Butkhuzi. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 87-90, (Russ.).

In this paper the method of organization of express and semi-express runs on international bus routes is developed according to all basic requirements to passenger transportation, which enables to receive mathematical formulas for their definition in concrete conditions of operation. Bibl. 5. Russ.

On a heat transferred to a cutting tool. M.S. Silogava. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 91-97, (Russ.).

To avoid heat accumulation in a cutting tool, for the purpose of improvement of its durability, taking into account speed, forced of cutting, thermo-mechanical parameters of a cutting tool and processing materials, it is determined a quantity of heat passed to the body of a tool for steady-state modes. 3 ill. Bibl. 5. Russ.


UNIFICATION AND TYPIFICATION OF TECHNOLOGICAL PROCESSES OF AUTOMATED ASSEMBLY OF DETAILS OF READI-MADE GARMENTS. T. Uriad­mkho­peli, L. Demetradze. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 98-100, (Russ.).

In the present work the problems of unification and typification of technological processes of processing and assemblage of details of ready-made garments are considered. 1 ill. Bibl. 5. Russ.


THE  APPLIANCE  OF  MODELING THE FLIGHT  DINAMICS. S. Khoshtaria, J. Ebanoidze, T. Labartkhava, M. Abramishvili. “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 101-105, (Russ.).

The  electronic modulator for the flight dynamics is suggested, that fulfils the realization of one of the method of flight imitation offered by the authors. The above-mentioned method implies the shift of the image on the screen of a monitor to the corresponding direction of the flight and angle, creating the effect of flight dynamics. 2 ill. Bibl. 3. Russ.


STUDY AND CALCULATION OF SINGLE-PIECE PARTING OF GARMENT DETAILS AND EXECUTIVE MECHANISMS. T. Uriadmkhopeli, T. Gamezardashvili, L. Demetradze, “Problems of Mechanics”. Tbilisi, 2007, ¹ 1(26), pp. 106-110, (Russ.).

In the present work we investigated the process of single-piece parting of garment details from a pack during the automated assemblage of these details on the assembly machine. 3 ill. Bibl. 9. Russ.