Determination of the moments of inertia with a self-oscillating electromechanical system

A method is considered for measuring the moments of inertia of products by the frequency of undamped oscillations in an electromechanical system with a contactless electrical machine having an active rotor. A measuring procedure is given and the results of experimental studies are reported.Translated from Izmeritel'naya Tekhnika, No. 4, p. 31–32, April, 1994.     

Generation of single chaotic microwave pulses in a self-oscillating ring system with ferromagnetic film under the action of external noise

The generation of single chaotic microwave pulses in a self-oscillating ring system with ferromagnetic film under the action of external narrow-band noise microwave signal occurring outside the band of frequencies of the chaotic microwave signal was observed. Chaotic generation emerged due to the parametric instability of the magnetostatic surface wave in the ferromagnetic film, whereas formation of single chaotic microwave pulses was caused by the absence of complete suppression of chaos under the action of narrowband noise.     

A route to chaos in a nonlinear oscillator with delay

Summary The paper presents an analysis of the transition from regular to chaotic motion in a Van der Pol-Duffing's oscillator with delay after a Hopf bifurcation. The conditions for the occurrence of the Hopf bifurcation have been determined by means of the approximate method. For the parameters near the bifurcation point a computer simulation of the vibrating system had been performed and the evolution of the system from regular motion to chaos has been analysed at the decrease of the value of the dimensionless damping coefficient.With 2 Figures     

Generation of chaotic microwave pulses in broadband self-oscillating ring system with ferromagnetic film under the action of external pulse-modulated microwave signal

We have experimentally studied specific features of the generation of chaotic microwave pulse trains in a self-oscillating ring system with nonlinear delay line on surface magnetostatic waves, bandpass filter, and power amplifier on GaAs field-effect transistors under the action of an external pulse-modulated microwave signal occurring outside the band of the generated chaotic signal. It is established that a decrease in the off/duty ratio in the external pulse-modulated microwave signal leads to an increase in this ratio for the chaotic microwave pulses. The integral power of the chaotic microwave signal generated under the pulsed external signal action is increased as compared to the power of signal generated in the autonomous regime.     

Dynamical behaviour of a friction oscillator with simultaneous self and external excitation

Friction-induced self-sustained oscillations, also known as stick-slip vibrations, occur in mechanical systems as well as in everyday life. In engineering applications these vibrations are undesirable and should be avoided. In the present paper it is shown how the very robust limit cycles of stick-slip vibrations can be broken up by a harmonic disturbance. Based on a simple model of a friction oscillator with simultaneous self and external excitation the resulting bifurcation behaviour and the routes to chaos are investigated for a wide range of system parameters. The influence of different types of friction characteristics is elaborated and the admissibility of smoothing procedures is examined by comparing results gained for non-smooth and smoothed friction characteristics.     

Transition to phase synchronization in a system with periodic dynamics under the action of a chaotic signal

Intermittent behavior has been studied near the boundary of phase synchronization in an autooscillatory system with periodic dynamics under the action of an external chaotic signal. It is shown that the intermittency obeys the same scenario as that observed in the case of interaction between two coupled chaotic oscillators.     

Determining the state of a potentially hazardous object with restricted initial information

An approach is presented to the determination of accident-rate category for a potentially hazardous object, which is exposed to unregulated factors and subject to restricted initial information. Formulas are derived for combining the information from various sources, which enable one to reduce the mean losses from erroneous decisions. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 19–22, March, 2006.     

A mathematical model of a crystal oscillator and clock in the form of an augmented system of state equations

An analysis of a mathematical model of a crystal oscillator and clock and disturbances in the form of an augmented system of state equations is performed. By means of such a model, it is possible to synthesize an optimal frequency-time stabilization system for the GLONASS/GPS synchronizing reference receiver. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 35–38, April, 2007.     

Control algorithm synthesis for a crystal oscillator and clock by the use of an adaptive state regulator

An optimal state regulator has been designed for a frequency-time stabilization system for the GLONASS/GPS reference synchronizing receiver, in which the controlled object is represented as an extended state-equation system. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 37–39, June, 2007.     

Response of an oscillator with non-linear damping and a softening spring to non-white random excitation

A generalised method of stochastic averaging is applied to a class of non-linear oscillators which have linear-plus-quadratic damping and linear-plus-cubic stiffness, with a softening spring characteristic. It is shown that, by approximating the total energy envelope of the oscillator as a one-dimensional Markov process, expressions for various response statistics can be deduced. A simple modification to the method is proposed which takes further account of the shape of the input spectrum. Comparisons between simulation results and predictions from the proposed theory indicate that the modification to the theory leads to improved accuracy. Comparisons between theory and simulation for the mean first passage time reveal that this statistic is sensitive to the magnitude of the input spectral bandwidth. The application of the theory to the prediction of the roll response of ships and transport barges to irregular wave excitation is discussed briefly.     

On the diagnostics of regular and chaotic motion regimes in a dynamic system using the number of states function

A method for determining the type of dynamic behavior is suggested. The method, based on constructing a function of the number of states of a system, is intended for diagnostics of the laminar and turbulent phases of motion in a system.     

Delay-independent stability of moments of a linear oscillator with delayed state feedback and parametric white noise

The stability of a linear oscillator with delayed state feedback driven by parametric Gaussian white noise is studied in this paper. The first and second order moment equations of the system response are derived by using moment method and Itô differential rule. Based on the moment equations, the delay-independent stable conditions of both moments are proposed: For the first order moment, the sufficient and necessary condition that guarantee delay-independent stability is identified to that of the deterministic system; for the second order moment, the sufficient condition that ensure delay-independent stability depends on noise intensity. The theoretical results are also illustrated with numerical simulations.     

Excitation of a phase-transformation wave in a metal under the action of a square surface heat pulse

We approximate the phase-transformation wave excited in a metal by the action of a square surface heat pulse when its surface density is given and the time of action is varied.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 4, pp. 615–621, April, 1981.     

Influence of the amplitude and phase nonlinearity of a spin-wave delay line on the wideband chaotic microwave generation

Regimes of wideband chaotic microwave generation have been studied in a self-oscillating ring system with a nonlinear delay line, in which magnetostatic backward volume waves (MSBVWs) are excited. It is established that a change in length of the delay line influences on its amplitude and phase nonlineartity, thus making it possible to control the characteristics of the chaotic microwave signal generated in the ring. It is demonstrated for the first time that a wideband chaotic microwave signal with a continuous spectrum and a nearly Gaussian probability density distribution can be generated by exciting MSBVWs in a self-oscillating ring system with a nonlinear delay line based on single ferromagnetic film.