Sharif Digital Repository

The usual practice in vehicle dynamic modeling is to consider the body and suspension components as rigid elements. The question this paper is trying to answer is; how large the errors will be if flexibility of the components are not considered in vehicle dynamic model. The flexible vehicle model made for this study has 300000 elements which are generated using Super-element analysis in MSC/NASTRAN and made usable in MSC/ADAMS environment using Craig-Bampton theorem. The full vehicle model made in ADAMS has 200 degrees of freedom and includes all bushings, mechanism, power train, and suspension system. The model was used in simulating ride and handling behavior of the vehicle in several... 

Review of waste management models indicate that optimization models based on the chain of waste flow are developed and applied in waste management systems. These models do represent the flow of material through few stages and they lack an integrated approach that may include the flow of material from the point of waste generation in different sectors till the end point at the land fill. It is also argued that the existing models do rarely consider the interrelated issues of economics, environment and social aspects. This conclusion has been followed by the development of an integrated multi stage and multi period dynamic model of waste flow based on quasi dynamic optimization techniques. The... 

In this paper the Extended Kalman Filter (EKF) has been used for the filtering of Electrocardiogram (ECG) signals. The method is based on a previously nonlinear dynamic model proposed for the generation of synthetic ECG signals. The results show that the EKF may be used as a powerful tool for the extraction of ECG signals from noisy measurements; which is the state of the art in applications such as the noninvasive extraction of fetal cardiac signals from maternal abdominal signals. © 2005 IEEE  

The necessity of dynamic equivalents for power system analysis has been well known since the expansion of large interconnected power networks, and has been discussed during the last decades. The present paper proposes a new method for constructing dynamic equivalents of power systems. In this method, at the first step the "study system" is modeled completely via a single machineinfinite bus modeling procedure. Then the "external system" is identified as a MIMO feedback block of this model in such a manner that can include dynamic effects of the latter on the behavior of the former. The method is successfully experimented on a part of the Iranian southern network. Copyright © 2007 The... 

Beside the major objective of providing congestion control, achieving predictable queuing delay, maximizing link utilization, and robustness are the main objectives of an active queue management (AQM) controller. This paper proposes an improved queue dynamic model while incorporating the packet drop probability as well. By applying the improved model, a new compensated PID AQM controller is developed for Transmission Control Protocol/Internet Protocol (TCP/IP) networks. The non-minimum phase characteristic caused by Padé approximation of the network delay restricts the direct application of control methods because of the unstable internal dynamics. In this paper, a parameter-varying dynamic... 

Dynamic modeling of piezo-driven compliant mechanisms is necessary to predict dynamic behavior of nanopositioning systems, and also to optimize their controlling methods. Dynamic tests on a real system or dynamic analyses on a FEM model is very time consuming when they must be carried out iteratively. According to previous works, obtaining static specifications of model is possible within a reasonable error margin. But all geometric dimensions and mass distribution details of the whole moving parts should be considered to calculate dynamic specifications of the model. In this paper, a functional method is described to obtain dynamic specifications of an planar compliant mechanism, by means... 

Greenhouses are complex systems that require considerable amounts of energy. In order to optimize their performance, it is necessary to reduce the amount of energy per unit of crop produced. This requires a combined assessment of greenhouse energy balance and crop growth, as well as their interaction. In this work, more than 30 existing greenhouse models are reviewed and different algorithms are combined to propose an integrated energy-yield model. The physical model of greenhouse energy demand is based on the dynamic energy and mass balance while yield production is based on a physiological crop model. The integrated model is validated with observed energy demand and crop yield datasets... 

Tactile sense is a key element in developing virtual reality simulators or surgical training systems. In this regard, haptic interfaces, the generator of a sense of touch, play a significant role in producing a realistic haptic feedback force. Since the majority of practical control theories are model-based, the identification of the robot dynamic model is a process of high importance and application. The main concern, accordingly, is to find a precise dynamic model for the aforementioned user interfaces. In this research, we have implemented the Lion identification method to characterize the dynamics of a parallel haptic device in actuating a surgery simulation. We chose the Novint Falcon... 

The development of a multiple model-based identification algorithm is addressed in this paper for nonlinear modeling of a conventional aircraft in the entire flight envelope. The dynamic model of an aircraft varies significantly depending on changes in the flight condition of the air vehicle including the altitude and the equivalent air speed. Therefore, the conventional identification approaches for generating a single nonlinear model with time-invariant parameters cannot be used in the entire flight envelope of an aircraft. Accordingly, a multiple model-based approach using nonlinear autoregressive exogenous neural networks is introduced in this paper as a powerful tool in identifying... 

Drill strings are subjected to complex coupled dynamics. Therefore, accurate dynamic modeling, which can represent the physical behavior of real drill strings, is of great importance for system analysis and control. The most widely used dynamic models for such systems are the lumped element models, which neglect the system distributed feature. In this paper, a dynamic model called neutral-type time delay model is modified to investigate the coupled axial–torsional vibrations in drill strings. This model is derived directly from the distributed parameter model by employing the d’Alembert method. Coupling of axial and torsional vibration modes occurs in the bit–rock interface. For the first... 

This paper presents an efficient algorithm based on a nonlinear dynamical model for the precise extraction of the characteristic points of electrocardiogram (ECG), which facilitates the HRV analysis. Determining the precise position of the waveforms of an ECG signal is complicated due to the varying amplitudes of its waveforms, the ambiguous and changing form of the complex and morphological variations with unknown sources of drift. A model-based approach handles these complications; therefore a method based on the usage of this concept in an extended Kalman filter structure has been developed. The fiducial points are detected using both the parameters of Gaussian-functions of the model, and... 

In this work we used the Liley EEG model as a dynamical model of EEG. Two parameters of the model which are candidates for change during an epileptic seizure are defined as new states in state space representation of this dynamical model. Then SIS particle filter is applied for estimating the defined states over time using the recorded epileptic EEG as the observation of the system. A method for fast numerical solution of the nonlinear coupled equation of the model is proposed. This model is used for tracking the dynamical properties of brain during epileptic seizure. Tracking the changes of these new defined states of the model have good information about the state transition of the model... 

Nitric Oxide (NO) provides myocardial oxygen demands of the heart during exercise and cardiac pacing and also prevents cardiovascular diseases such as atherosclerosis and platelet adhesion and aggregation. However, the direct in vivo measurement of NO in coronary arteries is still challenging. To address this matter, a mathematical model of dynamic changes of calcium and NO concentration in the coronary artery was developed for the first time. The model is able to simulate the effect of NO release in coronary arteries and its impact on the hemodynamics of the coronary arterial tree and also to investigate the vasodilation effects of arteries during cardiac pacing. For these purposes, flow... 

Nowadays, one of the most important challenges in developing greenhouses is meeting their energy demand. The other challenge is the high water consumption of evaporative-cooling systems in arid and semi-arid regions. In this study, a integrated dynamic model is developed to determine the greenhouse relative humidity, carbon dioxide, and temperature, considering transpiration. The model is applied to a greenhouse utilizing a ground to air heat transfer system, located in the Alborz province of Iran and the results are validated with experimental data. Energy and water performance of the greenhouse are evaluated for the case study greenhouse. Then, the model is applied to a greenhouse (similar... 

Since any error in the rotor angle caused by the resolver affects the entire permanent magnet synchronous motor (PMSM) control drive system, it is necessary to investigate its effect on mechanical vibrations. Torsional vibration is accordingly considered in the following study. Thereby, first, the effect of resolver errors on the harmonic content of motor current and, subsequently, torque ripple (TR) was investigated. Then, dynamical modeling is done for the generator-motor-resolver set to get the mechanical frequency response (FR) resulting from the resolver errors. Based on the above modeling, the dynamic equations (DEQs) of the system were derived, and the mechanical characteristics of... 

This paper compares the dynamic and static models of a Lithium-ion battery pack with its electrochemical model as energy storage of an electric vehicle according to the environmental protection agency drive cycles. The dynamic model or the RC equivalent circuit includes a voltage source and double parallel resistor and capacitor networks which are connected in series. The static model includes a voltage source and resistors. Given drive cycles, these models are compared in terms of the battery voltage, state-of-charge, and power loss in an electric vehicle in MapleSim software. Although the state-of-charge and power loss of both models are identical to each other, actually the terminal... 

This paper proposes a comprehensive analytic method for applying various optimal remedial actions to improve critical electromechanical modes damping without jeopardizing damping of non-critical modes and violating security constraints of power system. Generators and reactive power sources redisptach, demand side management and the generators voltage reference tuning are remedial actions that are considered here. Dynamic equations of the flux-decay dynamic model of generators, standard dynamic models of excitation system and power system stabilizer and algebraic equations of active and reactive powers balance are formulated in the quadratic eigenvalue problem framework. With simultaneous use...