NONLINEAR BEHAVIORS OF GEAR SHIFTING DIGITAL PHASE LOCKED LOOPS

2012 ◽  
Vol 22 (08) ◽  
pp. 1250204 ◽  
Author(s):  
XI CHEN ◽  
BINGO WING-KUEN LING ◽  
LI-MIN SUN
Keyword(s):  
Numerical Simulation ◽  
Adaptive Control ◽  
Steady State ◽  
Initial Conditions ◽  
Phase Locked Loops ◽  
Control Parameters ◽  
Dynamical Behaviors ◽  
Digital Phase Locked Loops ◽  
Simulation Results ◽  
Nonlinear Behaviors

Applying gear shifting algorithms to the implementation of Phase Locked Loops (PLLs) can significantly improve their performances. However, the behaviors of gear shifting digital PLLs (GSDPLLs) have not been fully studied due to the existence of newly adaptive control parameters. These parameters play a very important role in the design of GSDPLLs. In this paper, various nonlinear behaviors of GSDPLLs including the steady state periodic behaviors, divergent behaviors and chaotic behaviors, are studied. In particular, the effects of the initial conditions of GSDPLLs on their dynamical behaviors are investigated. The obtained results are useful for the design of GSDPLLs. Numerical simulation results are presented for illustrations.

Influence of Forming Residual Stresses on the Welding Distortions of Two Thick Plates

2009 ◽  
Vol 83-86 ◽  
pp. 125-132 ◽  
Author(s):  
Sebastien Gallée ◽  
Antoine Martin ◽  
Vincent Robin ◽  
Daniel Nelias
Keyword(s):  
Numerical Simulation ◽  
Electron Beam ◽  
Heat Source ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Initial Conditions ◽  
Rolling Process ◽  
Vacuum Vessel ◽  
Thick Plates ◽  
Simulation Results

The manufacturing of the ITER (International Thermonuclear Experimental Reactor) vacuum vessel involves the welding of thick deformed plates. The aim of this study is to investigate the influence of forming residual stresses on the welding distortions of two thick plates. The plates are deformed using a three point rolling process. A first numerical simulation is performed to investigate the residual stresses induced by this process. The forming residual stresses are taken into account as initial conditions to perform the electron beam welding simulation of a deformed plate. This simulation first requires calibrating the heat source. Two welding simulations are then performed: the first one with residual stresses and the second one without. The comparison of the simulation results points out a low effect of the residual stresses on the electron beam welding distortions. As a result, in the next electron beam welding simulations of the vacuum vessel, no forming residual stresses will be taken into account.

NUMERICAL SIMULATION OF AN ELECTRODYNAMIC TRANSDUCER CONTROL OF INSULIN PROVISION IN THE BERGMAN’S AND THE CHENG’S MODELS FOR THE DYNAMICS OF THE COUPLE GLUCOSE-INSULIN IN DIABETICS

2020 ◽  
Vol 20 (08) ◽  
pp. 2050055
Author(s):  
URSULE ESSAMBA MAH ◽  
PAUL WOAFO
Keyword(s):  
Numerical Simulation ◽  
Adaptive Control ◽  
Blood Glucose ◽  
Blood Glucose Level ◽  
Mathematical Models ◽  
Diabetic Patient ◽  
Glucose Level ◽  
Control Parameters ◽  
Level Control ◽  
Diabetic Person

This paper deals with the numerical simulation of a model of blood glucose level control of a diabetic person using an electrodynamic transducer. Two mathematical models describing the dynamics of the couple glucose–insulin are used: the Bergman’s and the Cheng’s models. First, the adaptive control is applied on the dynamics of a reservoir opener by an electrodynamic transducer. Then it is applied on the two models of the glucose–insulin dynamics. It is found that the control of the reservoir opener and that of the glycemia of a diabetic patient are efficient for some values of the control parameters.

scholarly journals Optimal Operation of Building Microgrids with Rooftop Greenhouse Under Component Outages in Islanded Mode

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1930
Author(s):  
Se-Hyeok Choi ◽  
Akhtar Hussain ◽  
Hak-Man Kim
Keyword(s):  
Numerical Simulation ◽  
Optimal Operation ◽  
Weight Matrix ◽  
Normal Operation ◽  
Control Parameters ◽  
Available Energy ◽  
Local Resources ◽  
Islanded Mode ◽  
Simulation Results ◽  
And Control

An optimal operation scheme for a building microgrid with a rooftop greenhouse in islanded mode is proposed in this paper. In islanded mode, the fulfillment of entire demand is challenging due to the absence of connection with the utility grid and the scarcity of local resources. The situation becomes more challenging when one or more pieces of equipment fail during the islanded mode. Therefore, in addition to islanded mode operation, component outage and recovery are also considered in this paper. In order to use the available energy efficiently, prioritization of building loads and control parameters of the greenhouse are proposed. A priority weight matrix is adopted to decide the supply of energy to fulfill the requirements of control parameters in the case of insufficient energy. In addition to the normal operation bounds, new bounds are defined to operate the control parameters if the resources are not sufficient. Additional penalties are imposed if the new bounds are chosen, due to violation of the normal operation range. The microgrid system is rescheduled if any component outage or recovery is detected from the outage point to the end of the scheduling horizon. The performance of the proposed method is evaluated by carrying out several simulations including component outage, component recovery, and simultaneous outage of two or more types of equipment. Numerical simulation results have demonstrated the effectiveness of the proposed operation scheme for optimal operation of building microgrids with a rooftop greenhouse in islanded mode.

scholarly journals Investigation of Chaotic and Strange Nonchaotic Phenomena in Nonautonomous Wien-Bridge Oscillator with Diode Nonlinearity

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
R. Rizwana ◽  
I. Raja Mohamed
Keyword(s):  
Numerical Simulation ◽  
Mean Square Displacement ◽  
Dynamical Variable ◽  
Mean Square ◽  
Maximal Lyapunov Exponent ◽  
Simulation Results ◽  
The One ◽  
Nonlinear Behaviors ◽  
Bifurcation Process ◽  
Electronic Oscillator

We have studied the chaotic and strange nonchaotic phenomena of a simple quasiperiodically forced Wien bridge oscillator circuit with diode as the only nonlinearity in this electronic oscillator system responsible for various nonlinear behaviors. Both the experimental results and the numerical simulation results for their confirmation are provided to show the bifurcation process. Various measures used for the numerical confirmation of SNA are power spectrum, maximal Lyapunov exponent, path of translational variables, mean square displacement, projection of poincaré section, log-log plot, and autocorrelation function. Based upon the numerical results, the birth of SNAs has been identified in the band merging route, intermittency route, and blowout bifurcation route. In addition, the birth of SNAs has been analyzed with peculiar mechanism, namely, “0-1 Test” employing the one state dynamical variable.

scholarly journals Parameter Estimation and Hybrid Lag Synchronization in Hyperchaotic Lü Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Qing Wei ◽  
Zuolei Wang
Keyword(s):  
Numerical Simulation ◽  
Parameter Estimation ◽  
Adaptive Control ◽  
Lyapunov Stability ◽  
Sufficient Conditions ◽  
Lyapunov Stability Theory ◽  
Unknown Parameters ◽  
Lag Synchronization ◽  
Control Approach ◽  
Simulation Results

The antiphase and complete lag synchronization of hyperchaotic Lü systems with unknown parameters is investigated. Based on the Lyapunov stability theory, the sufficient conditions for achieving hybrid lag synchronization are derived. The optimized parameter observers are approached analytically via adaptive control approach. Numerical simulation results are presented to verify the effectiveness of the proposed scheme.

Recent Research and Future Challenges in the Simulation of Hydraulic Seals

2009 ◽  
Author(s):  
Richard F. Salant ◽  
Bo Yang ◽  
Azam Thatte
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Future Research ◽  
Future Challenges ◽  
Simulation Results ◽  
Rod Seals

Recent numerical simulation results of hydraulic rod seals are reviewed. These include steady-state simulations of U-cup seals. Challenges for future research are discussed.

Combined Experimental and Numerical Study for Multiple Microchannel Heat Transfer System

2010 ◽  
Author(s):  
Jingru Zhang ◽  
Yogesh Jaluria ◽  
Tiantian Zhang ◽  
Li Jia
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Steady State ◽  
Numerical Model ◽  
Initial Conditions ◽  
Numerical Study ◽  
Numerical Models ◽  
Three Dimensional ◽  
Variation Versus ◽  
Heat Transfer System

Multiple microchannel heat sinks for potential use for electronic chip cooling are studied experimentally and numerically to characterize their thermal performance. The numerical simulation is driven by experimental data, which are obtained concurrently, to obtain realistic, accurate and validated numerical models. The ultimate goal is to design and optimize thermal systems. The experimental setup was established and liquid flow in the multiple microchannels was studied under different flow rates and heat influx. The temperature variation versus time was recorded by thermocouples, from which the time needed to reach steady state was determined. Temperature variations under steady state conditions were compared with three-dimensional steady state numerical simulation for the same boundary and initial conditions. The experimental data served as input parameters for the validation of the numerical model. In case of discrepancy, the numerical model was improved. A fairly good agreement between the experimental and simulation results was obtained. The numerical model also served to provide input that could be employed to improve and modify the experimental arrangement.

scholarly journals Investigation of a multi-ball, automatic dynamic balancing mechanism for eccentric rotors

2007 ◽  
Vol 366 (1866) ◽  
pp. 705-728 ◽  
Author(s):  
K Green ◽  
A.R Champneys ◽  
M.I Friswell ◽  
A.M Muñoz
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Steady State ◽  
Transient Response ◽  
Nonlinear Model ◽  
Practical Implementation ◽  
Dynamic Balancing ◽  
Qualitative And Quantitative ◽  
Simulation Results ◽  
Experimental Rig

This paper concerns an analytical and experimental investigation into the dynamics of an automatic dynamic balancer (ADB) designed to quench vibration in eccentric rotors. This fundamentally nonlinear device incorporates several balancing masses that are free to rotate in a circumferentially mounted ball race. An earlier study into the steady state and transient response of the device with two balls is extended to the case of an arbitrary number of balls. Using bifurcation analysis allied to numerical simulation of a fully nonlinear model, the question is addressed of whether increasing the number of balls is advantageous. It is found that it is never possible to perfectly balance the device at rotation speeds comparable with or below the first natural, bending frequency of the rotor. When considering practical implementation of the device, a modification is suggested where individual balls are contained in separate arcs of the ball race, with rigid partitions separating each arc. Simulation results for a partitioned ADB are compared with those from an experimental rig. Close qualitative and quantitative match is found between the theory and the experiment, confirming that for sub-resonant rotation speeds, the ADB at best makes no difference to the imbalance, and can make things substantially worse. Further related configurations worthy of experimental and numerical investigation are proposed.

Multiscroll Hyperchaotic System with Hidden Attractors and Its Circuit Implementation

2019 ◽  
Vol 29 (09) ◽  
pp. 1950117 ◽  
Author(s):  
Xin Zhang ◽  
Chunhua Wang
Keyword(s):  
Numerical Simulation ◽  
Adaptive Control ◽  
Theoretical Analysis ◽  
Chaotic System ◽  
Control Method ◽  
Hyperchaotic System ◽  
Circuit Implementation ◽  
Hidden Attractors ◽  
System A ◽  
Simulation Results

Based on the study on Jerk chaotic system, a multiscroll hyperchaotic system with hidden attractors is proposed in this paper, which has infinite number of equilibriums. The chaotic system can generate [Formula: see text] scroll hyperchaotic hidden attractors. The dynamic characteristics of the multiscroll hyperchaotic system with hidden attractors are analyzed by means of dynamic analysis methods such as Lyapunov exponents and bifurcation diagram. In addition, we have studied the synchronization of the system by applying an adaptive control method. The hardware experiment of the proposed multiscroll hyperchaotic system with hidden attractors is carried out using discrete components. The hardware experimental results are consistent with the numerical simulation results of MATLAB and the theoretical analysis results.

scholarly journals Research on the Numerical Simulation of the Nonlinear Dynamics of a Supercavitating Vehicle

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Tianhong Xiong ◽  
Xianyi Li ◽  
Yipin Lv ◽  
Wenjun Yi
Keyword(s):  
Numerical Simulation ◽  
Bifurcation Diagram ◽  
Control Parameters ◽  
System Parameters ◽  
Supercavitating Vehicle ◽  
Dynamical Behaviors ◽  
Movement Characteristics ◽  
Dimensional Dynamical System ◽  
Physical Phenomena ◽  
Periodic Bifurcation

Little is known about the movement characteristics of the supercavitating vehicle navigating underwater. In this paper, based on a four-dimensional dynamical system of this vehicle, its complicated dynamical behaviors were analyzed in detail by numerical simulation, according to the phase trajectory diagram, the bifurcation diagram, and the Lyapunov exponential spectrum. The influence of control parameters (such as various cavitation numbers and fin deflection angles) on the movement characteristics of the supercavitating vehicle was mainly studied. When the system parameters vary, various complicated physical phenomena, such as Hopf bifurcation, periodic bifurcation, or chaos, can be observed. Most importantly, it was found that the parameter range of the vehicle in a stable movement state can be effectively determined by a two-dimensional bifurcation diagram and that the behavior of the vehicle in the supercavity can be controlled by selecting appropriate control parameters to ensure stable navigation.

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