Papers by Keyword: Dynamical Model

Abstract: Econophysics is a new interdiscipline where physics concept and methods are applied to financial analysis. For example, the application of theoretical physics in the modeling of financial markets has aroused wide concern. In the process of random fluctuation of prices in financial markets, many nonlinear dynamical problems are hidden in set coefficients and assumptions, resulting in the invisibility of market price fluctuations and unavailability of hidden benefits in fluctuations. Based on the analysis of price fluctuation mechanism in financial markets, this paper analyzes the characteristics of price fluctuation, and constructs the dynamical model of price fluctuation by means of physics theory, thereby providing a theoretical reference for the control and prevention of transaction risks.

Abstract: This paper addresses motion simulation issues involved in a crane simulator with a 6-Degree-Of-Freedom platform. The crane dynamical models in terms of a range of motion equations are built for the operator cab in various main operating conditions. The ways to make the motion to be reproduced are investigated and the corresponding real-time motion cueing algorithm is proposed based on a special curve-merging approach. The algorithm is of simplified form and the needed computing time is very short, which makes it very practicable. The crane simulation system with this algorithm being adopted has been successfully developed and put into practice. The field application showed that the algorithm is able to ensure achievement of satisfied motion cueing effects. The proposed motion simulation models and the corresponding algorithm will provide significant reference value for developing similar motion simulation systems for all types of large-scale cranes or construction machinery.

Abstract: To study the changes of biomass of plankton and algae in lake environment, a new model was purposed. We applied the methods of qualitative analysis and numerical simulations. The main results were that there was a periodic solution, a globally stable equilibrium in this model under specific conditions, respectively. In conclusion, as increases of rate c, on which plankton are swallowed, there is a static equilibrium, a dynamic equilibrium, and then the equilibrium disappear, and at last the boundary point is globally stable, which means that plankton become extinct.

Abstract: The long length, light weight, low frequency, flexible joint and link of large space manipulators impact dynamic stability and position accuracy seriously. In this paper, dynamical model of space flexible manipulators system is build base on Lagrange method. With three DOF manipulators as the research object, the impact of flexible link, joint stiffness and clearance on the system frequency and end position accuracy of manipulator is simulated and analyzed. The results indicate that the flexible joint lead to low frequency vibration and flexible link lead to high frequency vibration. Low frequency vibration is the dominant impact of end position accuracy, Flexible joint have greater impact on the dynamic characteristics of system than that of flexible link.

Abstract: In order to explore the modal characteristics of the wind turbine, this paper researches how these natural frequencies of the major structural components within the operation speed range to avoid coupled resonance phenomenon. Aiming at 1500kW variable speed variable pitch double-fed wind turbines which are the mature products in market, the whole wind turbine dynamic modal equations are established by Lagrange method, and then process on-site testing is carried out to obtain measured modal characteristic parameters. The results of both theoretical and measured dates show that deviation between theoretical data and measured data, how the subsystem boundary conditions simplified methods to influence the rotor system natural frequencies, how the subsystem boundary conditions simplified methods to change the cross point of the rotor system natural frequencies with rotor speed 3P, and solution for wind turbine pass the cross point. The results will provide a certain extent guidance for the wind turbine development, design and optimization.

Abstract: In order to assess the safety of the explosive anti-riots munition, proceeding with the fragment’s force condition was analyzed in the flying process, the dynamical model of the fragment for the explosive anti-riots munition was deduced, then the velocity decay property of different shape fragments were calculated and analyzed also. The results show that the velocity decay of the spherical fragment is slowest, next came the rectangular fragment and the irregular shape fragment, with the same initial velocity (_v0) and separation angle (α), and the velocity decay of the same fragment at α >0 is more quickly than at α <0, with the same initial velocity (v0).

Abstract: The purpose of this paper is to experimentally validate the performance of a semi-active suspension incorporating a magneto-rheological damper (MR), where the parameters of the numerical models are often poorly adapted to real responses measured experimentally. To ensure a better representation of a real semi-active suspension, we must consider the internal dynamics of the MR damper in its numerical modeling. By adopting models which demonstrate that dynamic, such as the Bingham and Bouc-Wen models, we can approach the measured responses by adjusting their internal parameters. The law control introduction for feedback control of the semi-active suspension incorporating the internal dynamics of the MR damper allows, through the analysis of its robustness and response time, to better assess its performance. To validate the performance of these models, a comparative analysis was made between the experimentally measured responses by the dSPACE system used as an acquisition and control chain and the calculated or predicted responses. A rapprochement between measured responses and those calculated for the same dynamic characteristics of the test bed is possible by adjusting the most influential parameters of Bouc-Wen model.

Abstract: A simple control strategy is presented to control An inverted pendulum. The control strategy is obtained via mathematical derivation based on the dynamical model of the inverted pendulum system. That control law is simple and independent of the model of the controlled plant. It is applicable for the multi input single output systems similar to inverted pendulum systems. A controller based on that method was designed to control an inverted pendulum. The structure of the controller is simple. And the parameter adjusting is relatively easy. Then the simulation study was realized. The simulation result shows that control law is valid for the inverted pendulum system.

Abstract: The performance of a single-chamber pneumatic spring and a dual-chamber pneumatic spring have much difference. Dynamical models of these two types pneumatic springs were built and the characteristics of them were analyzed in this paper. Based on the theory of engineering thermodynamic, gas state equations were established and the dynamical models were obtained. The results show that: the single-chamber pneumatic spring can be equivalent to three stiffness springs in parallel and the dual-chamber pneumatic spring can be equivalent to a stiffness spring and a damping in series, then connect with three stiffness springs in parallel. The stiffness and natural frequency are main influenced by chamber pressure, effective area, volume of the chamber, displacement. The stiffness increases with the chamber pressure increasing and decreases with the volume of the chamber increasing. Such an accurate model for the pneumatic springs would contribute to more effective design or control of vibration isolation systems.

Abstract: The paper deals with a special class of robots, namely the hyper-redundant arm with continuum elements. First, the dynamic model of the tentacle arm during the motion toward the imposed position is analyzed. The dynamic model of the tentacle arm with continuum elements in conjunction with the electro-rheological fluid is discussed. Also, numerical simulations of the arm motion to the imposed target are presented.