PC based configurable aircraft simulation environment for dynamics and control analysis

Author(s):  
C. Zahringer ◽  
F. Holzapfel ◽  
G. Sachs
1991 ◽  
Vol 14 (5) ◽  
pp. 1021-1032 ◽  
Author(s):  
David C. Redding ◽  
William G. Breckenridge

Author(s):  
Xuri Yan ◽  
Michael Gevelber

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.


Author(s):  
H. S. Tzou ◽  
D. W. Wang

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.


Author(s):  
Aykut C. Satici ◽  
Fabio Ruggiero ◽  
Vincenzo Lippiello ◽  
Bruno Siciliano

Author(s):  
Federico Zenith ◽  
Ulrike Krewer

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.


Author(s):  
G. Lin ◽  
B. Balachandran ◽  
E. Abed

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.


Author(s):  
Bien Duong Xuan

Modern design always aims at reducing mass, simplifying the structure, and reducing the energy consumption of the system especially in robotics. These targets could lead to lowing cost of the material and increasing the operating capacity. The priority direction in robot design is optimal structures with longer lengths of the links, smaller and thinner links, more economical still warranting ability to work. However, all of these structures such as flexible robots are reducing rigidity and motion accuracy because of the effect of elastic deformations. Therefore, taking the effects of elastic factor into consideration is absolutely necessary for kinematic, dynamic modeling, analyzing, and controlling flexible robots. Because of the complexity of modeling and controlling flexible robots, the single-link and two-link flexible robots with only rotational joints are mainly mentioned and studied by most researchers. It is easy to realize that combining the different types of joints of flexible robots can extend their applications, flexibility, and types of structure. However, the models consisting of rotational and translational joints will make the kinematic, dynamic modeling, and control becomes more complex than models that have only rotational joints. This study focuses on the dynamics model and optimal controller based on genetic algorithms (GA) for a single flexible link robot (FLR) with a rigid translational joint. The motion equations of the FLR are built based on the Finite Element Method (FEM) and Lagrange Equations (LE). The difference between flexible manipulators that have only rotational joints and others with the translational joint is presented through boundary conditions. A PID controller is designed with parameters that are optimized by the GA algorithm. The cost function is established based on errors signal of translational joint, elastic displacements of the End-Point (EP) of the FLR. Simulation results show that the errors of the joint variable, the elastic displacements (ED) are destructed in a short time when the system is controlled following the reference point. The results of this study can be basic to research other flexible robots with more joint or combine joint styles.


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