- TITLE:
THEORETICAL CALCULATIONS OF POWER DENSITY VARIATION RANGES AS A FUNCTION OF RATE IN LASER-ASSISTED WELDING
- AUTHOR(S):
D. Nedeva, L. Lazov
- ABSTRACT:
The first phase of studying the process of laser-assisted welding necessarily goes through a preliminary theoretical physical-engineering analysis of the roles of the major manufacturing parameters. This is especially important for the practice when new technologies are being developed. This paper deals with the process of laser-assisted welding with a diode laser (λ=808 nm; 940 nm) by heat conduction of lamella
packs of electrical steel. On the basis of dependencies and correlations between physical quantities and manufacturing parameters of treatment, concrete numerical calculations of critical power density of melting and evaporation for specific values of welding rate have been presented.
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THEORETICAL CALCULATIONS OF POWER DENSITY VARIATION RANGES AS A FUNCTION OF RATE IN LASER-ASSISTED WELDING
- TITLE:
GYROSCOPE-FREE METHOD FOR MEASURING THE PARAMETERS OF MOVING OBJECTS
- AUTHOR(S):
D. Dichev
- ABSTRACT:
This paper presents a novel gyroscope-free method for measuring dynamic values that define oscillations in moving objects as related to the local vertical. The method is based on appropriate algorithm which utilizes signals from linear MEMS accelerometers interconnected in a differential way. High dynamic accuracy is obtained through real time processing of measuring signals by means of algorithm that has been developed as optimization criterion for the minimum of a mean quadratic error. Said algorithm is composed according to Kalman’s method and is intended to eliminate the impact of certain sources of interference each of which, individually, is of secondary importance though their cumulative action may cause a considerable distortion of the measuring signal. The method proposed eliminates the defects of
conventional measuring devices used in this particular area, being based on one hand on substantially simplified mechanical module, and on the achievements in nanotechnologies, microprocessor and computer engineering on the other. In compliance with the fundamental principles of this method there has been developed a special-purpose measuring system designed to measure board and keel rolling, heeling and trim of a ship. Results from experimental investigations, carried out with specially designed test-stand equipment in shape of a hexapode and operating with six degrees of freedom, prove the efficiency of proposed measuring approach.
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GYROSCOPE-FREE METHOD FOR MEASURING THE PARAMETERS OF MOVING OBJECTS
- TITLE:
DESIGN OF SYNCHRONIZATION SCHEMES WITH IMPERMANENT COUPLING BETWEEN TWO CHEN CHAOTIC SYSTEMS
- AUTHOR(S):
D. Chantov
- ABSTRACT:
The aim of this paper is to present an approach to design chaotic synchronization schemes with the possible most “economical” coupling between the master and the slave chaotic systems. The first point is to implement a coupling, in which only one of the master’s variables is used as a synchronization signal. To achieve this the so-called combined synchronization approach, proposed by the author earlier, is used. The second point is to investigate if a chosen coupling can be applied not continuously, as usual, but only for very short periods of time. Is this is possible, the real coupling between the master and the slave systems will exist only occasionally, but they will be constantly synchronized.
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DESIGN OF SYNCHRONIZATION SCHEMES WITH IMPERMANENT COUPLING BETWEEN TWO CHEN CHAOTIC SYSTEMS
- TITLE:
SYNTHESIS OF HYBRID SYNCHRONIZATION SCHEMES ON THE BASIS OF A MODEL OF HYPERCHAOTIC SYSTEM
- AUTHOR(S):
D. Chantov
- ABSTRACT:
Hybrid synchronization schemes for hypechaotic systems are presented in this paper. They are designed in accordance to the Lyapunov stability theory - control functions to the slave hyperchaotic system are designed in such way that the error system to have a stable zero equilibrium point. Hybrid synchronization is characterized with some identical and some reciprocal error functions and has some advantages in chaotic secure communication systems. A known hyperchaotic model – the hyperchaotic Rossler system is chosen for the synchronization system realization.
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SYNTHESIS OF HYBRID SYNCHRONIZATION SCHEMES ON THE BASIS OF A MODEL OF HYPERCHAOTIC SYSTEM
