Dynamics and Control of Supercavitating Bodies

2004 ◽  
Author(s):  
G. Lin ◽  
B. Balachandran ◽  
E. Abed
Keyword(s):  
Solution Structure ◽  
Piecewise Linear ◽  
Piecewise Linear Function ◽  
Control Analysis ◽  
Describing Function ◽  
Control Schemes ◽  
Loop Dynamics ◽  
Fundamental Understanding ◽  
Dynamics And Control ◽  
And Control

Analytical and numerical investigations conducted into the control of dive-plane dynamics of supercavitating bodies are presented. Particular attention is paid to tail-slap behavior. A fundamental understanding of the solution structure in terms of equilibrium and other solutions developed through the effort is discussed, and control schemes used to realize stable inner loop dynamics are presented. Dominant nonlinearities associated with planning forces are taken into account in the model and controllability of the system with the fin input and/or the cavitator input has been examined. The describing function method is brought to bear upon this problem and the presence of limit cycles in the controlled and uncontrolled cases are explored. The nonlinear planing force associated with tail-slap behavior is approximated as a piecewise linear function and the results obtained from switching feedback control analysis are provided.

Optical modeling for dynamics and control analysis

1991 ◽  
Vol 14 (5) ◽  
pp. 1021-1032 ◽  
Author(s):  
David C. Redding ◽  
William G. Breckenridge
Keyword(s):  
Control Analysis ◽  
Optical Modeling ◽  
Dynamics And Control ◽  
And Control

Process Dynamics and Control Analysis for Electrospinning Nanofibers

2010 ◽  
Author(s):  
Xuri Yan ◽  
Michael Gevelber
Keyword(s):  
Fiber Diameter ◽  
Electrospinning Process ◽  
Open Loop ◽  
Diameter Distribution ◽  
Control Analysis ◽  
Process Dynamics ◽  
Current State ◽  
Dynamics And Control ◽  
Process Reproducibility ◽  
And Control

In many emerging, high value electrospinning applications, the diameter distribution of electrospun fibers has important implications for the product’s performance and process reproducibility. However, the current state-of-the-art electrospinning process results in diameter distribution variations, both during a run and run-to-run. To address these problems, a vision-based, open loop system has been developed to better understand the process dynamics. The effects of process parameters on fiber diameter distributions are investigated, process dynamics are identified, and the relation between measurable variables and the resulting fiber diameter distribution is analyzed.

OTEC Plant Response and Control Analysis

1982 ◽  
Vol 104 (3) ◽  
pp. 208-215 ◽  
Author(s):  
W. L. Owens
Keyword(s):  
Nonlinear Differential Equations ◽  
System Response ◽  
Small Scale ◽  
Control Analysis ◽  
Plant Design ◽  
Operational Control ◽  
Response Curves ◽  
Control Schemes ◽  
Mass Flow Rates ◽  
And Control

An analysis is presented which allows prediction of closed-cycle OTEC power plant system response and control. Two basic operational control schemes are presented, which are primarily related to the type of seawater pumps employed. Variable flow seawater pumps allow optimization of the OTEC thermal-cycle state points for maximization of net generated power. Constant flow pumps are cheaper and simpler, but do not allow direct control over the evaporator and condenser operating temperatures. A system of nonlinear differential equations representing the basic elements of a constant seawater flow OTEC plant with turbine bypass flow control has been formulated for computer solution. Typical normalized response curves are presented for pressures, temperatures, mass flow rates, and generator speed for a small-scale, 50-kW OTEC plant design.

Dynamics and Control of Adaptive Nonlinear Piezothermoelastic Structures With Coupled Electric, Thermal and Mechanical Fields: A Finite Element Approach

2002 ◽  
Author(s):  
H. S. Tzou ◽  
D. W. Wang
Keyword(s):  
Finite Element ◽  
Electric Potential ◽  
Shell Element ◽  
Shell Structures ◽  
Control Analysis ◽  
Control Force ◽  
Vibration Sensing ◽  
Dynamics And Control ◽  
And Control ◽  
Piezoelectric Shell

Piezoelectric sensors and actuators are widely used in smart structures, mechatronic and structronic systems, etc. This paper is to investigate the dynamics and control of nonlinear laminated piezothermoelastic shell structures subjected to the combined mechanical, electrical, and thermal excitations by the finite element method. Governing relations of nonlinear strain-displacement, electric field-electric potential, and temperature gradient-temperature field for a piezothermoelastic shell are presented in a curvilinear coordinate system. Based on the layerwise constant shear angle theory, a generic curved triangular laminated piezothermoelastic shell element is developed. Generic nonlinear finite element formulations for vibration sensing and control analysis of laminated piezoelectric shell structures are derived based on the virtual work principle. Dynamic system equations, equations of electric potential output, and feedback control force are derived and discussed. The modified Newton-Raphson method is used for efficient nonlinear dynamic analysis of complex nonlinear piezoelectric/elastic/control structural systems. For vibration sensing and control, various control algorithms are implemented. The developed nonlinear piezothermoelastic shell element and finite element code are validated and applied to analysis of nonlinear flexible structronic systems. Vibration sensing and control of constant/non-constant curvature piezoelectric shell structures are studied. Thermal effect to static deflection, dynamic response, and control is investigated.

Intrinsic Euler-Lagrange dynamics and control analysis of the ballbot

2016 ◽  
Author(s):  
Aykut C. Satici ◽  
Fabio Ruggiero ◽  
Vincenzo Lippiello ◽  
Bruno Siciliano
Keyword(s):  
Control Analysis ◽  
Dynamics And Control ◽  
And Control

Dynamics and Control of a Portable DMFC System

2009 ◽  
Author(s):  
Federico Zenith ◽  
Ulrike Krewer
Keyword(s):  
Environmental Conditions ◽  
Direct Methanol Fuel Cells ◽  
Control Analysis ◽  
Control Loops ◽  
Current State ◽  
Current Implementation ◽  
Direct Methanol ◽  
Dynamics And Control ◽  
State Of Research ◽  
And Control

The current state of research on direct methanol fuel cells focuses heavily on the cell itself, with only a small minority of published articles about the management of the complete DMFC system. It is of particular importance to learn about the dynamics and control of such systems in order to provide autonomous and robust operation in spite of changing environmental conditions. We simulate and analyse a reference DMFC system consisting of, besides a model of the fuel cell, a mixer, coolers, separators, pumps and a fuel tank. A control analysis of a DMFC system is presented, to understand which variables are to be controlled by what means, and what constraints the system sets on the control loops. Some apparently negative phenomena can be beneficial to control performance: methanol cross-over stabilises the concentration dynamics and allows the usage of simple feedforward controllers. A portable DMFC system may be used in various environments, with very different environmental conditions. It is therefore explored how these conditions influence the system’s operation and control strategy, especially in regard to environmental temperature and humidity. The current implementation of the model has been designed to study the long-term transients, such as overall anode-loop water and energy holdups, assuming pseudo-steady state for most units.

On the Dynamics and Control of a Fractional Form of the Discrete Double Scroll

2019 ◽  
Vol 29 (06) ◽  
pp. 1950078 ◽  
Author(s):  
Adel Ouannas ◽  
Amina-Aicha Khennaoui ◽  
Samir Bendoukha ◽  
Giuseppe Grassi
Keyword(s):  
Fractional Order ◽  
Numerical Results ◽  
Phase Portraits ◽  
Bifurcation Diagrams ◽  
Complete Synchronization ◽  
General Behavior ◽  
Control Schemes ◽  
Dynamics And Control ◽  
And Control

This paper is concerned with the dynamics and control of the fractional version of the discrete double scroll hyperchaotic map. Using phase portraits and bifurcation diagrams, we show that the general behavior of the proposed map depends on the fractional order. We also present two control schemes for the proposed map, one that adaptively stabilizes the map, and another to achieve the complete synchronization of a pair of maps. Numerical results are presented to illustrate the findings.

On the Dynamics and Control of Fractional Chaotic Maps with Sine Terms

2020 ◽  
Vol 21 (6) ◽  
pp. 589-601 ◽  
Author(s):  
Ahlem Gasri ◽  
Adel Ouannas ◽  
Amina-Aicha Khennaoui ◽  
Samir Bendoukha ◽  
Viet-Thanh Pham
Keyword(s):  
Fractional Order ◽  
Chaotic Maps ◽  
Initial Conditions ◽  
Bifurcation Diagrams ◽  
Coexisting Attractors ◽  
Dynamical Behaviors ◽  
Control Schemes ◽  
Dynamics And Control ◽  
Numerical Tools ◽  
And Control

AbstractThis paper studies the dynamics of two fractional-order chaotic maps based on two standard chaotic maps with sine terms. The dynamic behavior of this map is analyzed using numerical tools such as phase plots, bifurcation diagrams, Lyapunov exponents and 0–1 test. With the change of fractional-order, it is shown that the proposed fractional maps exhibit a range of different dynamical behaviors including coexisting attractors. The existence of coexistence attractors is depicted by plotting bifurcation diagram for two symmetrical initial conditions. In addition, three control schemes are introduced. The first two controllers stabilize the states of the proposed maps and ensure their convergence to zero asymptotically whereas the last synchronizes a pair of non-identical fractional maps. Numerical results are used to verify the findings.

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