Experimental Techniques for Controlling Chaos in Lasers

1998 ◽  
Vol 08 (09) ◽  
pp. 1759-1768 ◽  
Author(s):  
R. Meucci ◽  
A. Labate ◽  
M. Ciofini
Keyword(s):  
Power Spectrum ◽  
Chaotic Dynamics ◽  
Feedback Loop ◽  
Control Parameter ◽  
Experimental Techniques ◽  
Controlling Chaos ◽  
Sinusoidal Modulation ◽  
Control Schemes ◽  
Frequency Components

This paper presents two control schemes for the chaotic dynamics of CO 2 laser with feedback which can be applied after the recognition of a leading frequency of the motion in the power spectrum. The first one is realized by means of a selective feedback loop which rejects all the frequency components except that of the leading cycle to be stabilized. The second one consists in a resonant sinusoidal modulation of the control parameter.

Control of Machine Tools and Robots

1986 ◽  
Vol 39 (9) ◽  
pp. 1331-1338 ◽  
Author(s):  
Yoram Koren
Keyword(s):  
Machine Tools ◽  
Degrees Of Freedom ◽  
Feedback Loop ◽  
Control Structure ◽  
Industrial Robots ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Control Schemes ◽  
Position Feedback ◽  
Recent Developments

The principal control structure of CNC machine tools and industrial robots is similar, since in both systems each axis of motion is separately controlled with a position feedback loop. Nevertheless, the control of robots is more complex, since they include more degrees of freedom and the motion of each joint is not independent of other joints. This paper compares the conventional control schemes of both systems, and summarizes recent developments in adaptive control of machine tools and robots.

Generation of Periodic Orbits from Chaotic Attractors of Weakly Coupled Diode Resonators

1997 ◽  
Vol 07 (04) ◽  
pp. 897-902
Author(s):  
Jong Cheol Shin ◽  
Sook-Il Kwun ◽  
Youngtae Kim
Keyword(s):  
Periodic Orbits ◽  
Chaotic Dynamics ◽  
Chaotic Attractors ◽  
Unstable Periodic Orbits ◽  
Chaotic Motions ◽  
Small Perturbations ◽  
Controlling Chaos ◽  
Weakly Coupled ◽  
Dynamical Properties

We have designed coupled diode resonators to study the effect of small perturbations due to weak symmetric coupling on chaotic dynamics. Our experiment clearly demonstrated that chaos of the diode resonators was suppressed so that chaotic motions were converted into periodic ones with small modifications to the attractor when an appropriate coupling signal perturbed the diode resonators. Many unstable periodic orbits were stabilized and they were very stable depending on the dynamical properties of the coupling signals. Our results suggest that coupling of signals belonging to the same class is effective in controlling chaos.

scholarly journals Algorithms for Controlling chaos: Application to BVP Oscillator

1993 ◽  
Vol 132 ◽  
pp. 45-45
Author(s):  
S. Rajeskar
Keyword(s):  
Computer Simulations ◽  
Limit Cycles ◽  
Digital Computer ◽  
Chaotic Dynamics ◽  
Van Der Pol Oscillator ◽  
Time Dependent ◽  
Van Der Pol ◽  
Small Magnitude ◽  
Controlling Chaos ◽  
Regular Motion

AbstractWe discuss how chaotic dynamics can be converted into regular motion in Bonhoeffer-van der Pol oscillator. Using a control signal proportional to the actual and desired outputs we study the control of fixed points and limit cycles by making time-dependent perturbations of amplitude of external force. We show the round-off induced periodicity in the digital computer simulations of orbits on chaotic attractor. We illustrate the stabilization of unstable periodic or bits by adding periodic pulses of small magnitude.

Abstract 231: Decreased Parasympathetic Activity in the Ovulatory Phase of the Menstrual Cycle

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Andrew Tweedell ◽  
Matthew Tenan ◽  
Anthony C Hackney ◽  
Matthew Brothers ◽  
Lisa Griffin
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Menstrual Cycle ◽  
Power Spectrum ◽  
High Frequency ◽  
Repeated Measures ◽  
Total Power ◽  
Cycle Phase ◽  
Autonomic Nervous ◽  
Frequency Components

The Heart rate variability (HRV) power spectrum is a non-invasive index of parasympathetic and sympathetic branches of the autonomic nervous system (ANS). Sex hormone oscillations may affect autonomic nervous system function; however, no systemic difference in HRV across the menstrual cycle has been shown. The purpose of this study is to test the hypothesis that there are changes in HRV spectral power components across the menstrual cycle. Method: Eleven women (24.4±3.6 years) volunteered for this experiment. Menstrual cycle phase was determined via basal body temperature mapping. Participants were tested once in each cycle phase. A 3 lead ECG was sampled at 1000 Hz. A piezoelectric force transducer, placed around the chest, recorded breathing rate. After 20 minutes of quiet seated rest, 5 minutes of data was collected in the upright seated position. Power spectral density analysis was performed on the R-R interval variations by fast Fourier transformation. The spectrum was divided into low (0.04-0.15, Hz) and high (0.15-0.40 Hz) frequency components. In order to attain data normality, the components were transformed with a natural logarithm. A repeated measures ANCOVA was used with a piece-wise covariate function for breathing rates higher and lower than 10 breaths per minute. Results: A significant decrease in total power spectrum was observed at the ovulatory phase (P=0.04) compared to the early follicular, late follicular and mid luteal phases. Furthermore, high-frequency oscillations were lower (P=0.04) in the ovulatory phase compared to late follicular phase. There were no changes observed (P>0.05) in the low frequency power spectrum across the menstrual cycle. Conclusions: The decrease in the high-frequency components of the HRV power spectrum during the ovulatory phase indicates a decrease in parasympathetic regulation of the heart. The ovulatory phase is characterized by an elevated level of progesterone, follicle stimulating and luteinizing hormones, and a moderate level of estradiol. Thus, the changes in these hormones during ovulation appear to affect ANS function.

Hybridization of Multi-chaotic Dynamics and Adaptive Control Parameter Adjusting jDE Strategy

2017 ◽  
pp. 77-87 ◽  
Author(s):  
Roman Senkerik ◽  
Michal Pluhacek ◽  
Ivan Zelinka ◽  
Adam Viktorin ◽  
Zuzana Kominkova Oplatkova
Keyword(s):  
Adaptive Control ◽  
Chaotic Dynamics ◽  
Control Parameter

CHAOTIC DYNAMICS OF A FIVE-DIMENSIONAL NONLINEAR NETWORK

2007 ◽  
Vol 18 (03) ◽  
pp. 335-342
Author(s):  
XUEWEI JIANG ◽  
DI YUAN ◽  
YI XIAO
Keyword(s):  
Lyapunov Exponent ◽  
Power Spectrum ◽  
Chaotic Dynamics ◽  
Period Doubling ◽  
Chinese Traditional Medicine ◽  
Bifurcation Diagrams ◽  
Nonlinear Network ◽  
Dynamical Behaviors ◽  
Lyapunov Exponent Spectrum ◽  
Period Doubling Bifurcations

The dynamics of a five-dimensional nonlinear network based on the theory of Chinese traditional medicine is studied by the Lyapunov exponent spectrum, Poincaré, power spectrum and bifurcation diagrams. The result shows that this system has complex dynamical behaviors, such as chaotic ones. It also shows that the system evolves into chaos through a series of period-doubling bifurcations.

EXPERIMENTAL EVIDENCE OF DIFFUSIVE DYNAMICS AND “RANDOM WALKING” IN A SIMPLE DETERMINISTIC MECHANICAL SYSTEM: THE SHAKEN PENDULUM

1992 ◽  
Vol 02 (04) ◽  
pp. 983-988 ◽  
Author(s):  
PHILIP V. BAYLY ◽  
LAWRANCE N. VIRGIN
Keyword(s):  
Time Series ◽  
Brownian Motion ◽  
Power Spectrum ◽  
Chaotic Dynamics ◽  
Angular Displacement ◽  
Translational Symmetry ◽  
Random Walking ◽  
Diffusive Dynamics ◽  
Nonlinear Maps ◽  
Deterministic Diffusion

An experimental model of a simple pendulum, harmonically shaken, displays chaotic dynamics. Moreover, in strongly excited chaotic regimes the time series of total angular displacement, which is rarely examined, wanders unboundedly, displaying a power spectrum which falls off as 1/fα over several decades. This behavior corresponds to deterministic diffusion, which has been found in simulations of nonlinear maps with periodic translational symmetry. The displacement time series obtained by sampling the pendulum displacement once per cycle is self-affine and quantitatively similar to Brownian motion.

scholarly journals Study of High Frequency Components in Electrocardiogram by Power Spectrum Analysis

1962 ◽  
Vol 10 (6) ◽  
pp. 870-879 ◽  
Author(s):  
Ernst K. Franke ◽  
John R. Braunstein ◽  
David C. Zellner
Keyword(s):  
Power Spectrum ◽  
Spectrum Analysis ◽  
High Frequency ◽  
Power Spectrum Analysis ◽  
Frequency Components

Stabilisation of Period-1 Orbits of the Hénon Map: Parametric Variation and Additive Noise

2001 ◽  
Author(s):  
Huw G. Davies
Keyword(s):  
Asymptotic Expansions ◽  
Noise Level ◽  
Control Parameter ◽  
Additive Noise ◽  
Period Doubling ◽  
Nonlinear Dynamic System ◽  
Hénon Map ◽  
Henon Map ◽  
Sinusoidal Modulation ◽  
Period Orbit

Abstract Slow sinusoidal modulation of a control parameter can maintain a low period orbit of a nonlinear dynamic system into parameter regions where the low period orbit is unstable, and a higher period orbit would normally occur. We examine this case for a period-doubling bifurcation of the Hénon map. Whether or not effective stabilisation of the period-1 orbit takes place depends on both the frequency of the variation and on the noise. Increasing the frequency tends to stabilise the orbit; increasing the noise level is destabilising. We use matched asymptotic expansions to describe the response, and find explicit expressions for the response which can estimate whether and where an apparent period doubling occurs.

Surface EMG power spectrum and intramuscular pH in human vastus lateralis muscle during dynamic exercise

1989 ◽  
Vol 67 (3) ◽  
pp. 1245-1249 ◽  
Author(s):  
P. Bouissou ◽  
P. Y. Estrade ◽  
F. Goubel ◽  
C. Y. Guezennec ◽  
B. Serrurier
Keyword(s):  
Power Spectrum ◽  
Vastus Lateralis ◽  
Dynamic Exercise ◽  
Vastus Lateralis Muscle ◽  
Muscle Lactate ◽  
Lactate Accumulation ◽  
Lateralis Muscle ◽  
Frequency Components ◽  
Emg Power Spectrum ◽  
Intramuscular Ph

The relationship between intramuscular pH and the frequency components of the surface electromyographic (EMG) power spectrum from the vastus lateralis muscle was studied in eight healthy male subjects during brief dynamic exercise. The studies were carried out in placebo control and metabolic alkalosis induced by oral administration of NaHCO3. At the onset of exercise, blood pH was 0.08 units higher in alkalosis compared with placebo. Muscle lactate accumulation during exercise was higher in alkalosis (32 +/- 5 mmol/kg wet wt) than in placebo (17 +/- 4 mmol/kg wet wt), but no difference in intramuscular pH was found between the two conditions. The EMG power spectrum was shifted toward lower frequencies during fatigue in the control condition (10.1 +/- 0.9%), and these spectral shifts, evaluated from changes in the mean power frequency (MPF) of the EMG power spectrum, were further accentuated in alkalosis (19 +/- 2%). Although the changes in frequency components of EMG correlated with muscle lactate accumulation (r = 0.68, P less than 0.01), no direct relationship with muscle pH was observed. We conclude that alkalosis results in a greater reduction in MPF associated with a higher muscle lactate accumulation. However, the good correlation observed between the two variables is not likely causative, and a dissociation between intramuscular pH and the increase in the low-frequency content of EMG power spectrum appears during muscle fatigue.

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